WorldWideScience

Sample records for satellite-based vehicle tracking

  1. Advanced Tracking of Vehicles

    DEFF Research Database (Denmark)

    Jensen, Christian Søndergaard; Li, K.-J.; Pakalnis, Stardas

    2005-01-01

    With the continued advances in wireless communications, geo-location technologies, and consumer electronics, it is becoming possible to accurately track the time-varying location of each vehicle in a population of vehicles. This paper reports on ongoing research that has as it objective to develop...... efficient tracking techniques. More specifically, while almost all commercially available tracking solutions simply offer time-based sampling of positions, this paper's techniques aim to offer a guaranteed tracking accuracy for each vehicle at the lowest possible costs, in terms of network traffic...... and server-side updates. This is achieved by designing, prototyping, and testing novel tracking techniques that exploit knowledge of the road network and past movement. These resulting tracking techniques are to support mobile services that rely on the existence of a central server that continuously tracks...

  2. TRACKED VEHICLE Rev 75

    Energy Technology Data Exchange (ETDEWEB)

    2007-05-08

    Revision 75 of the Tracked Vehicle software is a soft real-time simulation of a differentially steered, tracked mobile robot, which, because of the track flippers, resembles the iRobot PackBot (http://www.irobot.com/). Open source libraries are used for the physics engine (http://www.ode.org/), the display and user interface (http://www.mathies.com/cpw/), and the program command line and configuration file parameters (http://www.boost.org/). The simulation can be controlled by a USB joystick or the keyboard. The configuration file contains demonstration model parameters of no particular vehicle. This simulation can be used as a starting point for those doing tracked vehicle simulations. This simulation software is essentially a research tool which can be modified and adapted for certain types of tracked vehicle research. An open source license allows an individual researchers to tailor the code to their specific research needs.

  3. Vehicle Tracking and Security

    Science.gov (United States)

    Scorer, A. G.

    1998-09-01

    This paper covers the wide area and short range locational technologies that are available for vehicle tracking in particular and mobile user security in general. It also summarises the radio communications services that can deliver information to the user. It considers the use that can be made of these technologies, when combined with procedures for delivering a response, in the security field, notably in relation to personal security, high-value load protection and the after-theft tracking markets.

  4. Tracking target objects orbiting earth using satellite-based telescopes

    Energy Technology Data Exchange (ETDEWEB)

    De Vries, Willem H; Olivier, Scot S; Pertica, Alexander J

    2014-10-14

    A system for tracking objects that are in earth orbit via a constellation or network of satellites having imaging devices is provided. An object tracking system includes a ground controller and, for each satellite in the constellation, an onboard controller. The ground controller receives ephemeris information for a target object and directs that ephemeris information be transmitted to the satellites. Each onboard controller receives ephemeris information for a target object, collects images of the target object based on the expected location of the target object at an expected time, identifies actual locations of the target object from the collected images, and identifies a next expected location at a next expected time based on the identified actual locations of the target object. The onboard controller processes the collected image to identify the actual location of the target object and transmits the actual location information to the ground controller.

  5. Track Loading Vehicle - TLV

    Data.gov (United States)

    Federal Laboratory Consortium — The TLV is designed to apply forces close to the strength limits of the rails and other track structure components, such as ties, rail fasteners, and ballast, while...

  6. Vehicle Tracking Using Kalman Filter and Features

    Directory of Open Access Journals (Sweden)

    Amir Salarpour

    2011-09-01

    Full Text Available Vehicle tracking has a wide variety of applications. The image resolution of the video available from most traffic camera system is low. In many cases for tracking multi object, distinguishing them from another isn’t easy because of their similarity. In this paper we describe a method, for tracking multiple objects, where the objects are vehicles. The number of vehicles is unknown and varies. We detect all moving objects, and for tracking of vehicle we use the kalman filter and color feature and distance of it from one frame to the next. So the method can distinguish and tracking all vehicles individually. The proposed algorithm can be applied to multiple moving objects.

  7. Code Tracking Algorithms for Mitigating Multipath Effects in Fading Channels for Satellite-Based Positioning

    Directory of Open Access Journals (Sweden)

    Markku Renfors

    2007-12-01

    Full Text Available The ever-increasing public interest in location and positioning services has originated a demand for higher performance global navigation satellite systems (GNSSs. In order to achieve this incremental performance, the estimation of line-of-sight (LOS delay with high accuracy is a prerequisite for all GNSSs. The delay lock loops (DLLs and their enhanced variants (i.e., feedback code tracking loops are the structures of choice for the commercial GNSS receivers, but their performance in severe multipath scenarios is still rather limited. In addition, the new satellite positioning system proposals specify the use of a new modulation, the binary offset carrier (BOC modulation, which triggers a new challenge in the code tracking stage. Therefore, in order to meet this emerging challenge and to improve the accuracy of the delay estimation in severe multipath scenarios, this paper analyzes feedback as well as feedforward code tracking algorithms and proposes the peak tracking (PT methods, which are combinations of both feedback and feedforward structures and utilize the inherent advantages of both structures. We propose and analyze here two variants of PT algorithm: PT with second-order differentiation (Diff2, and PT with Teager Kaiser (TK operator, which will be denoted herein as PT(Diff2 and PT(TK, respectively. In addition to the proposal of the PT methods, the authors propose also an improved early-late-slope (IELS multipath elimination technique which is shown to provide very good mean-time-to-lose-lock (MTLL performance. An implementation of a noncoherent multipath estimating delay locked loop (MEDLL structure is also presented. We also incorporate here an extensive review of the existing feedback and feedforward delay estimation algorithms for direct sequence code division multiple access (DS-CDMA signals in satellite fading channels, by taking into account the impact of binary phase shift keying (BPSK as well as the newly proposed BOC modulation

  8. Dynamic Analysis of a Military- Tracked Vehicle

    Directory of Open Access Journals (Sweden)

    V. Balamurugan

    2000-04-01

    Full Text Available 'The ride dynamic characteristics of a typical medium weight, high speed military-tracked vehicle for negotiating rough cross-counlry terrain have been studied. The vehicle is modelled using finiteelement simulation method with beam and shell elements. An eigenvalue analysis has been done to estimate natural modes ofNibration of the vehicle. The dynamic response of certain salient locations is obtained by carrying out a transient dynamic analysis using implicit Newmark beta method. A constant forwar vehicle speed and non-deformable sinusoidal terrain profile are assumed.

  9. Innovative control systems for tracked vehicle platforms

    CERN Document Server

    2014-01-01

     This book has been motivated by an urgent need for designing and implementation of innovative control algorithms and systems for tracked vehicles. Nowadays the unmanned vehicles are becoming more and more common. Therefore there is a need for innovative mechanical constructions capable of adapting to various applications regardless the ground, air or water/underwater environment. There are multiple various activities connected with tracked vehicles. They can be distributed among three main groups: design and control algorithms, sensoric and vision based in-formation, construction and testing mechanical parts of unmanned vehicles. Scientists and researchers involved in mechanics, control algorithms, image processing, computer vision, data fusion, or IC will find this book useful.

  10. Magnetic navigation and tracking of underwater vehicles

    Digital Repository Service at National Institute of Oceanography (India)

    Teixeira, F.C.; Pascoal, A.M.

    to errors in measurement data; 1 We emphasize that the Euler equation which applies to a local magnetic anomaly cannot be applied to the total ambient field which does not behave as a homogeneous function of the same degree. Tarantola (2005). Commonly..., and max. errors Problem Inversion SQUID FluxGate Navigation Analytic 1.6m n.a. Tracking Analytic 0.13m 1.7m Tracking Monte Carlo 0.4m RMS 0.7m RMS provides the localization of the vehicle relatively to the magnetic landmarks observed in real time...

  11. GPS based Advanced Vehicle Tracking and Vehicle Control System

    Directory of Open Access Journals (Sweden)

    Mashood Mukhtar

    2015-02-01

    Full Text Available Security systems and navigators have always been a necessity of human‟s life. The developments of advanced electronics have brought revolutionary changes in these fields. In this paper, we will present a vehicle tracking system that employs a GPS module and a GSM modem to find the location of a vehicle and offers a range of control features. To complete the design successfully, a GPS unit, two relays, a GSM Modem and two MCU units are used. There are five features introduced in the project. The aim of this project is to remotely track a vehicle‟s location, remotely switch ON and OFF the vehicle‟s ignition system and remotely lock and unlock the doors of the vehicle. An SMS message is sent to the tracking system and the system responds to the users request by performing appropriate actions. Short text messages are assigned to each of these features. A webpage is specifically designed to view the vehicle‟s location on Google maps. By using relay based control concept introduced in this paper, number of control features such as turning heater on/off, radio on/off etc. can be implemented in the same fashion.

  12. A New Damper for Tracked Vehicle Suspension

    Institute of Scientific and Technical Information of China (English)

    FAN Fu-sheng; LI Meng; XING Zhi; L(U) Jian-gang

    2005-01-01

    The passive suspension system of tracked vehicle is designed to get its suspension parameters based on a certain common velocity and a certain road surface roughness. Its performance optimization only exists in a certain operating mode without far-ranging adaptability. Holding the damper basic frame form and applying semi-active suspension system based on MR (magnetorheological) damper, the vehicle can keep its optimum efficiency between energy dissipation and vibration reduction in all kinds of operating modes. Theoretical analysis and experiments show that the damping performances provided by this MRF(magnetorheological fluids) vane damper are same as those provided by traditional damper, and the new damper has the better controllability and adaptability.

  13. Real-time vehicle tracking for traffic monitoring systems

    Institute of Scientific and Technical Information of China (English)

    胡硕

    2016-01-01

    A real-time vehicle tracking method is proposed for traffic monitoring system at road intersec-tions, and the vehicle tracking module consists of an initialization stage and a tracking stage .Li-cense plate location based on edge density and color analysis is used to detect the license plate re -gion for tracking initialization .In the tracking stage , covariance matching is employed to track the license plate .Genetic algorithm is used to reduce the computational cost .Real-time image tracking of multi-lane vehicles is achieved .In the experiment , test videos are recorded in advance by record-ers of actual E-police systems at several different city intersections .In the tracking module , the av-erage false detection rate and missed plates rate are 1.19%, and 1.72%, respectively.

  14. Vision-based multiple vehicle detection and tracking at nighttime

    Science.gov (United States)

    Xu, Wencong; Liu, Hai

    2011-08-01

    In this paper, we develop a robust vision-based approach for real-time traffic data collection at nighttime. The proposed algorithm detects and tracks vehicles through detection and location of vehicle headlights. First, we extract headlights candidates by an adaptive image segmentation algorithm. Then we group headlights candidates that belong to the same vehicle by spatial clustering and generate vehicle hypotheses by rule-based reasoning. The potential vehicles are then tracked over frames by region search and pattern analysis methods. The spatial and temporal continuity extracted from tracking process is used to confirm vehicle's presence. To handle problem of occlusions, we apply Kalman Filter to motion estimation. We test the algorithm on the video clips of nighttime traffic under different conditions. The experimental results show that real-time vehicle counting and tacking for multi-lanes are achieved and the total detection rate is above 96%.

  15. Vision-based vehicle detection and tracking algorithm design

    Science.gov (United States)

    Hwang, Junyeon; Huh, Kunsoo; Lee, Donghwi

    2009-12-01

    The vision-based vehicle detection in front of an ego-vehicle is regarded as promising for driver assistance as well as for autonomous vehicle guidance. The feasibility of vehicle detection in a passenger car requires accurate and robust sensing performance. A multivehicle detection system based on stereo vision has been developed for better accuracy and robustness. This system utilizes morphological filter, feature detector, template matching, and epipolar constraint techniques in order to detect the corresponding pairs of vehicles. After the initial detection, the system executes the tracking algorithm for the vehicles. The proposed system can detect front vehicles such as the leading vehicle and side-lane vehicles. The position parameters of the vehicles located in front are obtained based on the detection information. The proposed vehicle detection system is implemented on a passenger car, and its performance is verified experimentally.

  16. Interaction of railway vehicles with track in cross-winds

    Science.gov (United States)

    Xu, Y. L.; Ding, Q. S.

    2006-04-01

    This paper presents a framework for simulating railway vehicle and track interaction in cross-wind. Each 4-axle vehicle in a train is modeled by a 27-degree-of-freedom dynamic system. Two parallel rails of a track are modeled as two continuous beams supported by a discrete-elastic foundation of three layers with sleepers and ballasts included. The vehicle subsystem and the track subsystem are coupled through contacts between wheels and rails based on contact theory. Vertical and lateral rail irregularities simulated using an inverse Fourier transform are also taken into consideration. The simulation of steady and unsteady aerodynamic forces on a moving railway vehicle in cross-wind is then discussed in the time domain. The Hilber Hughes Taylor α-method is employed to solve the nonlinear equations of motion of coupled vehicle and track systems in cross-wind. The proposed framework is finally applied to a railway vehicle running on a straight track substructure in cross-wind. The safety and comfort performance of the moving vehicle in cross-wind are discussed. The results demonstrate that the proposed framework and the associated computer program can be used to investigate interaction problems of railway vehicles with track in cross-wind.

  17. Ride Dynamics of a Tracked Vehicle with a Finite Element Vehicle Model

    Directory of Open Access Journals (Sweden)

    S. Jothi

    2016-01-01

    Full Text Available Research on tracked vehicle dynamics is by and large limited to multi-rigid body simulation. For realistic prediction of vehicle dynamics, it is better to model the vehicle as multi-flexible body. In this paper, tracked vehicle is modelled as a mass-spring system with sprung and unsprung masses of the physical tracked vehicle by Finite element method. Using the equivalent vehicle model, dynamic studies are carried out by imparting vertical displacement inputs to the road wheels. Ride characteristics of the vehicle are captured by modelling the road wheel arms as flexible elements using Finite element method. In this work, a typical tracked vehicle test terrain viz., Trapezoidal blocks terrain (APG terrain is considered. Through the simulations, the effect of the road wheel arm flexibility is monitored. Result of the analysis of equivalent vehicle model with flexible road wheel arms, is compared with the equivalent vehicle model with rigid road wheel arms and also with the experimental results of physical tracked vehicle. Though there is no major difference in the vertical bounce response between the flexible model and the rigid model, but there is a visible difference in the roll condition. Result of the flexible vehicle model is also reasonably matches with the experimental result.Defence Science Journal, Vol. 66, No. 1, January 2016, pp. 19-25, DOI: http://dx.doi.org/10.14429/dsj.66.9201

  18. Observable dynamics and coordinate systems for vehicle tracking

    CERN Document Server

    Altendorfer, Richard

    2010-01-01

    We investigate several coordinate systems and dynamical vector fields for target tracking to be used in driver assistance systems. We show how to express the discrete dynamics of maneuvering target vehicles in arbitrary coordinates starting from the target's and the own (ego) vehicle's assumed dynamical model in global coordinates. We clarify the notion of "ego compensation" and show how non-inertial effects are to be included when using a body-fixed coordinate system for target tracking. We finally compare the tracking error of different combinations of target tracking coordinates and dynamical vector fields for simulated data.

  19. Multisensor simultaneous vehicle tracking and shape estimation

    NARCIS (Netherlands)

    Elfring, J.; Appeldoorn, R.; Kwakkernaat, M.

    2016-01-01

    This work focuses on vehicle automation applications that require both the estimation of kinematic and geometric information of surrounding vehicles, e.g., automated overtaking or merging. Rather then using one sensor that is able to estimate a vehicle's geometry from each sensor frame, e.g., a lida

  20. Fuzzy Logic Control for Suspension Systems of Tracked Vehicles

    Institute of Scientific and Technical Information of China (English)

    YU Yang; WEI Xue-xia; ZHANG Yong-fa

    2009-01-01

    A scheme of fuzzy logic control for the suspension system of a tracked vehicle is presented.A mechanical model for the whole body of a tracked vehicle,which is totally a fifteen-degree-of-freedom system,is established.The model includes the vertical motion,the pitch motion as well as the roll motion of the tracked vehicle.In contrast to most previous studies,the coupling effect among the vertical,the pitch and the roll motions of the suspension system of a tracked vehicle is considered simultaneously.The simulation of fuzzy logic control under road surface with random excitation shows that the acceleration,pitch angle and roll angle of suspension system can be efficiently controlled.

  1. Close-Range Tracking of Underwater Vehicles Using Light Beacons.

    Science.gov (United States)

    Bosch, Josep; Gracias, Nuno; Ridao, Pere; Istenič, Klemen; Ribas, David

    2016-03-25

    This paper presents a new tracking system for autonomous underwater vehicles (AUVs) navigating in a close formation, based on computer vision and the use of active light markers. While acoustic localization can be very effective from medium to long distances, it is not so advantageous in short distances when the safety of the vehicles requires higher accuracy and update rates. The proposed system allows the estimation of the pose of a target vehicle at short ranges, with high accuracy and execution speed. To extend the field of view, an omnidirectional camera is used. This camera provides a full coverage of the lower hemisphere and enables the concurrent tracking of multiple vehicles in different positions. The system was evaluated in real sea conditions by tracking vehicles in mapping missions, where it demonstrated robust operation during extended periods of time.

  2. Close-Range Tracking of Underwater Vehicles Using Light Beacons

    Science.gov (United States)

    Bosch, Josep; Gracias, Nuno; Ridao, Pere; Istenič, Klemen; Ribas, David

    2016-01-01

    This paper presents a new tracking system for autonomous underwater vehicles (AUVs) navigating in a close formation, based on computer vision and the use of active light markers. While acoustic localization can be very effective from medium to long distances, it is not so advantageous in short distances when the safety of the vehicles requires higher accuracy and update rates. The proposed system allows the estimation of the pose of a target vehicle at short ranges, with high accuracy and execution speed. To extend the field of view, an omnidirectional camera is used. This camera provides a full coverage of the lower hemisphere and enables the concurrent tracking of multiple vehicles in different positions. The system was evaluated in real sea conditions by tracking vehicles in mapping missions, where it demonstrated robust operation during extended periods of time. PMID:27023547

  3. Vehicle path tracking by integrated chassis control

    Institute of Scientific and Technical Information of China (English)

    Saman Salehpour; Yaghoub Pourasad; Seyyed Hadi Taheri

    2015-01-01

    The control problem of trajectory based path following for passenger vehicles is studied. Comprehensive nonlinear vehicle model is utilized for simulation vehicle response during various maneuvers in MATLAB/Simulink. In order to follow desired path, a driver model is developed to enhance closed loop driver/vehicle model. Then, linear quadratic regulator (LQR) controller is developed which regulates direct yaw moment and corrective steering angle on wheels. Particle swam optimization (PSO) method is utilized to optimize the LQR controller for various dynamic conditions. Simulation results indicate that, over various maneuvers, side slip angle and lateral acceleration can be reduced by 10%and 15%, respectively, which sustain the vehicle stable. Also, anti-lock brake system is designed for longitudinal dynamics of vehicle to achieve desired slip during braking and accelerating. Proposed comprehensive controller demonstrates that vehicle steerability can increase by about 15% during severe braking by preventing wheel from locking and reducing stopping distance.

  4. Strong tracking adaptive Kalman filters for underwater vehicle dead reckoning

    Institute of Scientific and Technical Information of China (English)

    XIAO Kun; FANG Shao-ji; PANG Yong-jie

    2007-01-01

    To improve underwater vehicle dead reckoning, a developed strong tracking adaptive kalman filter is proposed. The filter is improved with an additional adaptive factor and an estimator of measurement noise covariance. Since the magnitude of fading factor is changed adaptively, the tracking ability of the filter is still enhanced in low velocity condition of underwater vehicles. The results of simulation tests prove the presented filter effective.

  5. Vision-Based Leader Vehicle Trajectory Tracking for Multiple Agricultural Vehicles.

    Science.gov (United States)

    Zhang, Linhuan; Ahamed, Tofael; Zhang, Yan; Gao, Pengbo; Takigawa, Tomohiro

    2016-04-22

    The aim of this study was to design a navigation system composed of a human-controlled leader vehicle and a follower vehicle. The follower vehicle automatically tracks the leader vehicle. With such a system, a human driver can control two vehicles efficiently in agricultural operations. The tracking system was developed for the leader and the follower vehicle, and control of the follower was performed using a camera vision system. A stable and accurate monocular vision-based sensing system was designed, consisting of a camera and rectangular markers. Noise in the data acquisition was reduced by using the least-squares method. A feedback control algorithm was used to allow the follower vehicle to track the trajectory of the leader vehicle. A proportional-integral-derivative (PID) controller was introduced to maintain the required distance between the leader and the follower vehicle. Field experiments were conducted to evaluate the sensing and tracking performances of the leader-follower system while the leader vehicle was driven at an average speed of 0.3 m/s. In the case of linear trajectory tracking, the RMS errors were 6.5 cm, 8.9 cm and 16.4 cm for straight, turning and zigzag paths, respectively. Again, for parallel trajectory tracking, the root mean square (RMS) errors were found to be 7.1 cm, 14.6 cm and 14.0 cm for straight, turning and zigzag paths, respectively. The navigation performances indicated that the autonomous follower vehicle was able to follow the leader vehicle, and the tracking accuracy was found to be satisfactory. Therefore, the developed leader-follower system can be implemented for the harvesting of grains, using a combine as the leader and an unloader as the autonomous follower vehicle.

  6. Stochastic analysis model for vehicle-track coupled systems subject to earthquakes and track random irregularities

    Science.gov (United States)

    Xu, Lei; Zhai, Wanming

    2017-10-01

    This paper devotes to develop a computational model for stochastic analysis and reliability assessment of vehicle-track systems subject to earthquakes and track random irregularities. In this model, the earthquake is expressed as non-stationary random process simulated by spectral representation and random function, and the track random irregularities with ergodic properties on amplitudes, wavelengths and probabilities are characterized by a track irregularity probabilistic model, and then the number theoretical method (NTM) is applied to effectively select representative samples of earthquakes and track random irregularities. Furthermore, a vehicle-track coupled model is presented to obtain the dynamic responses of vehicle-track systems due to the earthquakes and track random irregularities at time-domain, and the probability density evolution method (PDEM) is introduced to describe the evolutionary process of probability from excitation input to response output by assuming the vehicle-track system as a probabilistic conservative system, which lays the foundation on reliability assessment of vehicle-track systems. The effectiveness of the proposed model is validated by comparing to the results of Monte-Carlo method from statistical viewpoint. As an illustrative example, the random vibrations of a high-speed railway vehicle running on the track slabs excited by lateral seismic waves and track random irregularities are analyzed, from which some significant conclusions can be drawn, e.g., track irregularities will additionally promote the dynamic influence of earthquakes especially on maximum values and dispersion degree of responses; the characteristic frequencies or frequency ranges respectively governed by earthquakes and track random irregularities are greatly different, moreover, the lateral seismic waves will dominate or even change the characteristic frequencies of system responses of some lateral dynamic indices at low frequency.

  7. Hypersonic Vehicle Tracking Based on Improved Current Statistical Model

    Directory of Open Access Journals (Sweden)

    He Guangjun

    2013-11-01

    Full Text Available A new method of tracking the near space hypersonic vehicle is put forward. According to hypersonic vehicles’ characteristics, we improved current statistical model through online identification of the maneuvering frequency. A Monte Carlo simulation is used to analyze the performance of the method. The results show that the improved method exhibits very good tracking performance in comparison with the old method.

  8. Vehicle detection and tracking based on phase-correlation

    Institute of Scientific and Technical Information of China (English)

    Yi He(何毅); Xin Yang(杨新)

    2004-01-01

    This paper presents vehicle detection and tracking algorithms based on real-time background (RTB) and phase-correlation (PC) in the video sequence of urban highway with fixed camera. Firstly moving objects are obtained by subtracting RTB from serial images. After classification, PC is used to determine corresponding regions of moving objects between consecutive frames. The problems of vehicles' merging and splitting, sudden stop, and restart are also considered. Experiments show that the method is practical and can realize real-time detection and tracking of vehicles on highway.

  9. H∞ control for path tracking of autonomous underwater vehicle motion

    Directory of Open Access Journals (Sweden)

    Lin-Lin Wang

    2015-05-01

    Full Text Available In order to simplify the design of path tracking controller and solve the problem relating to nonlinear dynamic model of autonomous underwater vehicle motion planning, feedback linearization method is first adopted to transform the nonlinear dynamic model into an equivalent pseudo-linear dynamic model in horizontal coordinates. Then considering wave disturbance effect, mixed-sensitivity method of H∞ robust control is applied to design state-feedback controller for this equivalent dynamic model. Finally, control law of pseudo-linear dynamic model is transformed into state (surge velocity and yaw angular rate tracking control law of nonlinear dynamic model through inverse coordinate transformation. Simulation indicates that autonomous underwater vehicle path tracking is successfully implemented with this proposed method, and the influence of parameter variation in autonomous underwater vehicle dynamic model on its tracking performance is reduced by H∞ controller. All the results show that the method proposed in this article is effective and feasible.

  10. Moving Vehicle Detection and Tracking Algorithm in Traffic Video

    Directory of Open Access Journals (Sweden)

    Shisong Zhu

    2013-06-01

    Full Text Available Aiming at the defects and shortages of traditional moving vehicles detection algorithms, by the analysis and comparison of the existing detection algorithms, we propose an algorithm that combined with frames with symmetric difference and background difference to detect moving vehicle in this paper. First, two different difference images by using frames with symmetric difference and background difference are gained respectively and two binary images can be gained by the appropriate threshold, then the contour of moving vehicles can be extracted by applying OR operation in the two binary images. Finally, the precise moving vehicles will be gained by mathematic morphological methods. In this paper we use Harris operator, Feature Points such as edges and corners are extracted, followed by block-matching to track the Feature Points in successive viedo frames. Many vehicles can be tracked at the same time automatically since  the  information is obtained from video sequences.

  11. Stereo-Based Tracking-by-Multiple Hypotheses Framework for Multiple Vehicle Detection and Tracking

    Directory of Open Access Journals (Sweden)

    Young-Chul Lim

    2013-07-01

    Full Text Available In this paper, we present a tracking‐by‐multiple hypotheses framework to detect and track multiple vehicles accurately and precisely. The tracking‐by‐ multiple hypotheses framework consists of obstacle detection, vehicle recognition, visual tracking, global position tracking, data association and particle filtering. The multiple hypotheses are from obstacle detection, vehicle recognition and visual tracking. The obstacle detection detects all the obstacles on the road. The vehicle recognition classifies the detected obstacles as vehicles or non-vehicles. 3D feature‐based visual tracking estimates the current target state using the previous target state. The multiple hypotheses should be linked to corresponding tracks to update the target state. The hierarchical data association method assigns multiple tracks to the correct hypotheses with multiple similarity functions. In the particle filter framework, the target state is updated using the Gaussian motion model and the observation model with associated multiple hypotheses. The experimental results demonstrate that the proposed method enhances the accuracy and precision of the region of interest.

  12. Metric Tracking of Launch Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA needs reliable, accurate navigation for launch vehicles and other missions. GPS is the best world-wide navigation system, but operates at low power making it...

  13. 3D Track-keeping Method for Autonomous Underwater Vehicle

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; Bian Xin-Qian; Chang Zong-Hu

    2002-01-01

    In this paper, 3D track-keeping control method for autonomous underwater vehicle (AUV) with and without the influence of ocean current is investigated. Because the system to be controlled is highly nonlinear and strong coupled, an approach is used to divide it into two subsystems. One is to control the heading and the track error on the horizontal plane. The other is to control the pitch and the track error on the vertical plane. The results of computer simulation show that the autopilot works properly, it can capture the current waypoint and turns to track the next path automatically.

  14. PARTICLE FILTER BASED VEHICLE TRACKING APPROACH WITH IMPROVED RESAMPLING STAGE

    Directory of Open Access Journals (Sweden)

    Wei Leong Khong

    2014-02-01

    Full Text Available Optical sensors based vehicle tracking can be widely implemented in traffic surveillance and flow control. The vast development of video surveillance infrastructure in recent years has drawn the current research focus towards vehicle tracking using high-end and low cost optical sensors. However, tracking vehicles via such sensors could be challenging due to the high probability of changing vehicle appearance and illumination, besides the occlusion and overlapping incidents. Particle filter has been proven as an approach which can overcome nonlinear and non-Gaussian situations caused by cluttered background and occlusion incidents. Unfortunately, conventional particle filter approach encounters particle degeneracy especially during and after the occlusion. Particle filter with sampling important resampling (SIR is an important step to overcome the drawback of particle filter, but SIR faced the problem of sample impoverishment when heavy particles are statistically selected many times. In this work, genetic algorithm has been proposed to be implemented in the particle filter resampling stage, where the estimated position can converge faster to hit the real position of target vehicle under various occlusion incidents. The experimental results show that the improved particle filter with genetic algorithm resampling method manages to increase the tracking accuracy and meanwhile reduce the particle sample size in the resampling stage.

  15. Cold Regions Test of Tracked and Wheeled Vehicles

    Science.gov (United States)

    2015-12-11

    ft). (3) Test slopes of 5%, 10%, and 15% grades in asphalt or concrete surfaces and slopes of 20%, 30%, 40%, and 60% in gravel and concrete ...may be modified or otherwise exempted depending on the military requirements. b. All operator and maintenance operations should be attempted...the braking tests. Caution must be exercised when braking of a tracked vehicle at high speed if using rubber track pads without grousers or ice

  16. Detecting traffic hot spots using vehicle tracking data

    Science.gov (United States)

    Xu, Zhimin; Lin, Zhiyong; Zhou, Cheng; Huang, Changqing

    2016-03-01

    Vehicle tracking data for thousands of urban vehicles and the availability of digital map provide urban planners unprecedented opportunities for better understanding urban transportation. In this paper, we aim to detect traffic hot spots on urban road networks using vehicle tracking data. Our approach first proposes an integrated map-matching algorithm based on the road buffer and vehicle driving direction, to find out which road segment the vehicle is travelling on. Then, we estimate travel speed by calculating the average the speed of every vehicle on a certain road segment, which indicates traffic status, and create the spatial weights matrices based on the connectivity of road segments, which expresses the spatial dependence between each road segment. Finally, the measure of global and local spatial autocorrelation is used to evaluate the spatial distribution of the traffic condition and reveal the traffic hot spots on the road networks. Experiments based on the taxi tracking data and urban road network data from Wuhan have been performed to validate the detection effectiveness.

  17. Track-to-track association for object matching in an inter-vehicle communication system

    Science.gov (United States)

    Yuan, Ting; Roth, Tobias; Chen, Qi; Breu, Jakob; Bogdanovic, Miro; Weiss, Christian A.

    2015-09-01

    Autonomous driving poses unique challenges for vehicle environment perception due to the complex driving environment the autonomous vehicle finds itself in and differentiates from remote vehicles. Due to inherent uncertainty of the traffic environments and incomplete knowledge due to sensor limitation, an autonomous driving system using only local onboard sensor information is generally not sufficiently enough for conducting a reliable intelligent driving with guaranteed safety. In order to overcome limitations of the local (host) vehicle sensing system and to increase the likelihood of correct detections and classifications, collaborative information from cooperative remote vehicles could substantially facilitate effectiveness of vehicle decision making process. Dedicated Short Range Communication (DSRC) system provides a powerful inter-vehicle wireless communication channel to enhance host vehicle environment perceiving capability with the aid of transmitted information from remote vehicles. However, there is a major challenge before one can fuse the DSRC-transmitted remote information and host vehicle Radar-observed information (in the present case): the remote DRSC data must be correctly associated with the corresponding onboard Radar data; namely, an object matching problem. Direct raw data association (i.e., measurement-to-measurement association - M2MA) is straightforward but error-prone, due to inherent uncertain nature of the observation data. The uncertainties could lead to serious difficulty in matching decision, especially, using non-stationary data. In this study, we present an object matching algorithm based on track-to-track association (T2TA) and evaluate the proposed approach with prototype vehicles in real traffic scenarios. To fully exploit potential of the DSRC system, only GPS position data from remote vehicle are used in fusion center (at host vehicle), i.e., we try to get what we need from the least amount of information; additional feature

  18. A Robust Algorithm of Contour Extraction for Vehicle Tracking

    Institute of Scientific and Technical Information of China (English)

    FANZhimin; ZHOUJie; GAODashan

    2003-01-01

    Contour extraction of moving vehicle is an important and challenging issue in traffic surveillance. In this paper, a robust algorithm is proposed for contour ex-traction and moving vehicle tracking. First, we establish a modified snake model and utilize the directional infor-mation of the edge map to guide the snaxels' behavior.Then an adaptive shape restriction is embedded into the algorithm to govern the scope of the snake's motion, and Kalman filter is employed to estimate spatio-temporal rela-tionship between successive frames. In addition~ multiple refinements are suggested to compensate for the snake's vulnerability to fake edges. All of them contribute to a ro-bust overall performance in contour extraction and vehicle tracking. Experimental results in real traffic scene prove the effectiveness of our algorithm.The comparison with conventional snakes is also provided.

  19. Mobile system for locating and tracking vehicles in distress

    Science.gov (United States)

    Landi, Giuliano; Stoica, Axente D.

    2000-02-01

    This report relates to a mobile system for tracking and protection of vehicles owned by some banking organizations, security institutions or by some social service for fire, medical rescue or taxicabs, by an operator placed also aboard of a vehicle in which he has at his disposal all the necessary means for precise determination of the position and the state of each vehicle from the fleet that is under his surveying. Therefore in contrast to the operating mode of the localization systems known in present and which have in its composition a stable center for permanent surveying, the operator of the system presented in this report can intervene personally and in an efficient mode in the aid of the vehicle in distress.

  20. Autopilot Control Synthesis for Path Tracking Maneuvers of Underwater Vehicles

    Institute of Scientific and Technical Information of China (English)

    Sam-Sang YOU; Hyeung-Sik CHOI; Hwan-Seong KIM; Han-Il PARK

    2011-01-01

    This paper is concerned with the robust control synthesis of autonomous underwater vehicle (AUV) for general path following maneuvers. First, we present maneuvering kinematics and vehicle dynamics in a unified framework. Based on H loop-shaping procedure, the 2-DOF autopilot controller has been presented to enhance stability and path tracking.By use of model reduction, the high-order control system is reduced to one with reasonable order, and further the scaled low-order controller has been analyzed in both the frequency and the time domains. Finally, it is shown that the autopilot control system provides robust performance and stability against prescribed levels of uncertainty.

  1. Real-time vehicle tracking for driving assistance

    OpenAIRE

    Fossati, Andrea; Schönmann, Patrick; Fua, Pascal

    2010-01-01

    Detecting car taillights at night is a task which can nowadays be accomplished very fast on cheap hardware. We rely on such detections to build a vision-based system that, coupling them in a rule-based fashion, is able to detect and track vehicles. This allows the generation of an interface that informs a driver of the relative distance and velocity of other vehicles in real time and triggers a warning when a potentially dangerous situation arises. We demonstrate the system using sequences sh...

  2. Maneuvering Vehicle Tracking Based on Multi-sensor Fusion

    Institute of Scientific and Technical Information of China (English)

    CHENYing; HANChong-Zhao

    2005-01-01

    Maneuvering targets tracking is a fundamental task in intelligent vehicle research. This paper focuses on the problem of fusion between radar and image sensors in targets tracking. In order to improve positioning accuracy and narrow down the image working area, a novel method that integrates radar filter with image intensity is proposed to establish an adaptive vision window.A weighted Hausdorff distance is introduced to define the functional relationship between image and model projection, and a modified simulated annealing algorithm is used to find optimum orientation parameter. Furthermore, the global state is estimated, which refers to the distributed data fusion algorithm. Experiment results show that our method is accurate.

  3. Combined Optimal Sizing and Control for a Hybrid Tracked Vehicle

    Directory of Open Access Journals (Sweden)

    Huei Peng

    2012-11-01

    Full Text Available The optimal sizing and control of a hybrid tracked vehicle is presented and solved in this paper. A driving schedule obtained from field tests is used to represent typical tracked vehicle operations. Dynamics of the diesel engine-permanent magnetic AC synchronous generator set, the lithium-ion battery pack, and the power split between them are modeled and validated through experiments. Two coupled optimizations, one for the plant parameters, forming the outer optimization loop and one for the control strategy, forming the inner optimization loop, are used to achieve minimum fuel consumption under the selected driving schedule. The dynamic programming technique is applied to find the optimal controller in the inner loop while the component parameters are optimized iteratively in the outer loop. The results are analyzed, and the relationship between the key parameters is observed to keep the optimal sizing and control simultaneously.

  4. Recognizing and tracking humans and vehicles using radar

    Science.gov (United States)

    Tahmoush, David; Silvious, Jerry

    2010-01-01

    Dynamic obstacles like vehicles and animals can be distinguished from humans using their radar micro-Doppler signature. This allows customizing the robotic path algorithm to avoid highly sensitive and unpredictable obstacles like humans and rapidly moving obstacles like vehicles. We demonstrate the extraction of stride rate and other information associated with gait for enhanced person recognition from radar data. We describe the radar sensors used for the measurements, the algorithms used for the detection, tracking, and classification of people and vehicles, as well as describe some of the features that can be extracted. These features can serve as rudimentary identifying information in a scene with multiple subjects. We measure human subjects in indoor and outdoor clutter backgrounds for identification and gather ground truth using video to validate the radar data.

  5. Optimal Vibration Control for Tracked Vehicle Suspension Systems

    Directory of Open Access Journals (Sweden)

    Yan-Jun Liang

    2013-01-01

    Full Text Available Technique of optimal vibration control with exponential decay rate and simulation for vehicle active suspension systems is developed. Mechanical model and dynamic system for a class of tracked vehicle suspension vibration control is established and the corresponding system of state space form is described. In order to prolong the working life of suspension system and improve ride comfort, based on the active suspension vibration control devices and using optimal control approach, an optimal vibration controller with exponential decay rate is designed. Numerical simulations are carried out, and the control effects of the ordinary optimal controller and the proposed controller are compared. Numerical simulation results illustrate the effectiveness of the proposed technique.

  6. An Unmanned Tracked Vehicle for Snow Research Applications

    Directory of Open Access Journals (Sweden)

    R.K. Das

    2016-12-01

    Full Text Available Lightweight robotic vehicles can be designed for over-snow mobility to carry out a variety of snow and glacier related studies like carrying out GPR survey of cracks & crevasses over ice crusts that cannot support foot travel, for collecting snow samples and carrying out sub-surface experiments with penetrometers on terrain that are dangerous for human, GPS mapping of avalanche debris etc. Sinkage, resistance to snow compaction, loss of traction and ingestion of snow into the driving system are some of the challenges that an unmanned lightweight tracked vehicle faces in snowbound terrain. In present work, a lightweight and unmanned remotely operated vehicle (ROV is conceptualized and developed as a technological solution. In this paper design and features of this vehicle, named HimBot, are presented along with the results obtained from tests carried over snow at Solang Nullah field observatory of SASE in February 2013. The outcome of this work will help in developing an optimized design of an ROV for over snow mobility for a variety of applications.

  7. Research on Fuzzy Control for Automatic Transmission of Tracked Vehicles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A principle of fuzzy control for tracked vehicles is proposed to make its automatic transmission system be able to adapt complex running conditions, and a model of its power train is established to be used in simulation. Based on the fuzzy control method, a fuzzy shift control system composed of a basic shift strategy and a fuzzy modification module is developed to improve the dynamic characteristics and cross-country maneuverability. Simulation results show that the fuzzy shift strategy can improve the shift quality under manifold driving conditions and avoid cycled shift effectively. Therefore,the proposed fuzzy shift strategies are proved to be feasible and practicable.

  8. A Low-Cost Vehicle Tracking Platform using Secure SMS

    DEFF Research Database (Denmark)

    Jacobsen, Rune Hylsberg; Aliu, Drini; Ebeid, Emad Samuel Malki

    2017-01-01

    This paper investigates the possibility of elevating SMS (Short Message Service) to support a cloud-based vehicle-tracking platform. A secure application protocol over SMS is introduced to circumvent the security issues that may succumb the SMS. We propose a cost-effective Internet of Things (IoT......) solution to countries dominated with GSM mobile infrastructure taking into close consideration technology usage and the mobile network infrastructure available. A common-off-the-shelf (COTS) IoT device such as the Raspberry Pi single board computer is depicted relying on GPS-GSM technologies envisioned...

  9. Tracking Object Existence From an Autonomous Patrol Vehicle

    Science.gov (United States)

    Wolf, Michael; Scharenbroich, Lucas

    2011-01-01

    An autonomous vehicle patrols a large region, during which an algorithm receives measurements of detected potential objects within its sensor range. The goal of the algorithm is to track all objects in the region over time. This problem differs from traditional multi-target tracking scenarios because the region of interest is much larger than the sensor range and relies on the movement of the sensor through this region for coverage. The goal is to know whether anything has changed between visits to the same location. In particular, two kinds of alert conditions must be detected: (1) a previously detected object has disappeared and (2) a new object has appeared in a location already checked. For the time an object is within sensor range, the object can be assumed to remain stationary, changing position only between visits. The problem is difficult because the upstream object detection processing is likely to make many errors, resulting in heavy clutter (false positives) and missed detections (false negatives), and because only noisy, bearings-only measurements are available. This work has three main goals: (1) Associate incoming measurements with known objects or mark them as new objects or false positives, as appropriate. For this, a multiple hypothesis tracker was adapted to this scenario. (2) Localize the objects using multiple bearings-only measurements to provide estimates of global position (e.g., latitude and longitude). A nonlinear Kalman filter extension provides these 2D position estimates using the 1D measurements. (3) Calculate the probability that a suspected object truly exists (in the estimated position), and determine whether alert conditions have been triggered (for new objects or disappeared objects). The concept of a probability of existence was created, and a new Bayesian method for updating this probability at each time step was developed. A probabilistic multiple hypothesis approach is chosen because of its superiority in handling the

  10. Optimisation of Kinematics for Tracked Vehicle Hydro Gas Suspension System

    Directory of Open Access Journals (Sweden)

    S. Sridhar

    2006-11-01

    Full Text Available The modern-day armoured fighting vehicles (AFVs are basically tracked vehicles equippedwith hydro gas suspensions, in lieu of conventional mechanical suspensions like torsion barand coil spring bogie suspensions. The uniqueness of hydro gas suspension is that it offersa nonlinear spring rate, which is very much required for the cross-country moveability of atracked vehicle. The AFVs have to negotiate different cross-country terrains like sandy, rocky,riverbed, etc. and the road irregularities provide enumerable problems during dynamic loadingsto the design of hydro gas suspension system. Optimising various design parameters demandsinnovative design methodologies to achieve better ride performance. Hence, a comprehensivekinematic analysis is needed. In this study, a methodology has been derived to optimise thekinematics of the suspension by reorienting the cylinder axis and optimising the loadtransferringleverage factor so that the side thrust on the cylinder is minimised to a greaterextent. The optimisation ultimately increases the life of the high-pressure and high-temperaturepiston seals, resulting in enhanced system life for better dependability.

  11. Real-time vehicle detection and tracking in video based on faster R-CNN

    Science.gov (United States)

    Zhang, Yongjie; Wang, Jian; Yang, Xin

    2017-08-01

    Vehicle detection and tracking is a significant part in auxiliary vehicle driving system. Using the traditional detection method based on image information has encountered enormous difficulties, especially in complex background. To solve this problem, a detection method based on deep learning, Faster R-CNN, which has very high detection accuracy and flexibility, is introduced. An algorithm of target tracking with the combination of Camshift and Kalman filter is proposed for vehicle tracking. The computation time of Faster R-CNN cannot achieve realtime detection. We use multi-thread technique to detect and track vehicle by parallel computation for real-time application.

  12. TRACKING VEHICLE IN GSM NETWORK TO SUPPORT INTELLIGENT TRANSPORTATION SYSTEMS

    Directory of Open Access Journals (Sweden)

    Z. Koppanyi

    2012-07-01

    Full Text Available The penetration of GSM capable devices is very high, especially in Europe. To exploit the potential of turning these mobile devices into dynamic data acquisition nodes that provides valuable data for Intelligent Transportation Systems (ITS, position information is needed. The paper describes the basic operation principles of the GSM system and provides an overview on the existing methods for deriving location data in the network. A novel positioning solution is presented that rely on handover (HO zone measurements; the zone geometry properties are also discussed. A new concept of HO zone sequence recognition is introduced that involves application of Probabilistic Deterministic Finite State Automata (PDFA. Both the potential commercial applications and the use of the derived position data in ITS is discussed for tracking vehicles and monitoring traffic flow. As a practical cutting edge example, the integration possibility of the technology in the SafeTRIP platform (developed in an EC FP7 project is presented.

  13. NONLINEAR ESTIMATION METHODS FOR AUTONOMOUS TRACKED VEHICLE WITH SLIP

    Institute of Scientific and Technical Information of China (English)

    ZHOU Bo; HAN Jianda

    2007-01-01

    In order to achieve precise, robust autonomous guidance and control of a tracked vehicle, a kinematic model with longitudinal and lateral slip is established. Four different nonlinear filters are used to estimate both state vector and time-varying parameter vector of the created model jointly. The first filter is the well-known extended Kalman filter. The second filter is an unscented version of the Kalman filter. The third one is a particle filter using the unscented Kalman filter to generate the importance proposal distribution. The last one is a novel and guaranteed filter that uses a linear set-membership estimator and can give an ellipsoid set in which the true state lies. The four different approaches have different complexities, behavior and advantages that are surveyed and compared.

  14. Tracking Vehicle in GSM Network to Support Intelligent Transportation Systems

    Science.gov (United States)

    Koppanyi, Z.; Lovas, T.; Barsi, A.; Demeter, H.; Beeharee, A.; Berenyi, A.

    2012-07-01

    The penetration of GSM capable devices is very high, especially in Europe. To exploit the potential of turning these mobile devices into dynamic data acquisition nodes that provides valuable data for Intelligent Transportation Systems (ITS), position information is needed. The paper describes the basic operation principles of the GSM system and provides an overview on the existing methods for deriving location data in the network. A novel positioning solution is presented that rely on handover (HO) zone measurements; the zone geometry properties are also discussed. A new concept of HO zone sequence recognition is introduced that involves application of Probabilistic Deterministic Finite State Automata (PDFA). Both the potential commercial applications and the use of the derived position data in ITS is discussed for tracking vehicles and monitoring traffic flow. As a practical cutting edge example, the integration possibility of the technology in the SafeTRIP platform (developed in an EC FP7 project) is presented.

  15. Fuzzy Adaptive Control for Trajectory Tracking of Autonomous Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Saeed Nakhkoob

    2014-01-01

    Full Text Available In this paper, the problem of the position and attitude tracking of an autonomous underwater vehicle (AUV in the horizontal plane, under the presence of ocean current disturbances is discussed. The effect of the gradual variation of the parameters is taken into account. The effectiveness of the adaptive controller is compared with a feedback linearization method and fuzzy gain control approach. The proposed strategy has been tested through simulations. Also, the performance of the propos-ed method is compared with other strategies given in some other studies. The boundedness and asymptotic converge-nce properties of the control algorithm and its semi-global stability are analytically proven using Lyapunov stability theory and Barbalat’s lemma.

  16. The Dynamics of a Railway Vehicle on a Disturbed Track

    DEFF Research Database (Denmark)

    Christiansen, Lasse Engbo

    of the main differences between this work and previous ones is that the vertical degrees of freedom are included making the model very realistic as this allows a dynamic calculation of the penetration depth in the contact area. In chapter two the model of the bogie is described, this is followed by a chapter...... describing how the wheel-rail interaction is modelled. The fourth chapter gives a presentation of the numerical algorithms used in this work. The fifth chapter presents the results obtained during this work, it begins with an brief investigation of the dynamics when running on a straight track. The second...... changing the velocity of the railway vehicle and the phase between the sinusoidal irregularities of the rails. In the final section the eigenfrequencies of the bogie are found and the most important modes are described. Chapter six is a discussion of the obtained results, and these are related...

  17. Vehicle tracking and classification in challenging scenarios via slice sampling

    Science.gov (United States)

    Nieto, Marcos; Unzueta, Luis; Barandiaran, Javier; Cortés, Andoni; Otaegui, Oihana; Sánchez, Pedro

    2011-12-01

    This article introduces a 3D vehicle tracking system in a traffic surveillance environment devised for shadow tolling applications. It has been specially designed to operate in real time with high correct detection and classification rates. The system is capable of providing accurate and robust results in challenging road scenarios, with rain, traffic jams, casted shadows in sunny days at sunrise and sunset times, etc. A Bayesian inference method has been designed to generate estimates of multiple variable objects entering and exiting the scene. This framework allows easily mixing different nature information, gathering in a single step observation models, calibration, motion priors and interaction models. The inference of results is carried out with a novel optimization procedure that generates estimates of the maxima of the posterior distribution combining concepts from Gibbs and slice sampling. Experimental tests have shown excellent results for traffic-flow video surveillance applications that can be used to classify vehicles according to their length, width, and height. Therefore, this vision-based system can be seen as a good substitute to existing inductive loop detectors.

  18. PRIMUS: autonomous navigation in open terrain with a tracked vehicle

    Science.gov (United States)

    Schaub, Guenter W.; Pfaendner, Alfred H.; Schaefer, Christoph

    2004-09-01

    The German experimental robotics program PRIMUS (PRogram for Intelligent Mobile Unmanned Systems) is focused on solutions for autonomous driving in unknown open terrain, over several project phases under specific realization aspects for more than 12 years. The main task of the program is to develop algorithms for a high degree of autonomous navigation skills with off-the-shelf available hardware/sensor technology and to integrate this into military vehicles. For obstacle detection a Dornier-3D-LADAR is integrated on a tracked vehicle "Digitized WIESEL 2". For road-following a digital video camera and a visual perception module from the Universitaet der Bundeswehr Munchen (UBM) has been integrated. This paper gives an overview of the PRIMUS program with a focus on the last program phase D (2001 - 2003). This includes the system architecture, the description of the modes of operation and the technology development with the focus on obstacle avoidance and obstacle classification using a 3-D LADAR. A collection of experimental results and a short look at the next steps in the German robotics program will conclude the paper.

  19. Analysis and Comparison of Electric Drive System Projects of Military Tracked Vehicles

    Institute of Scientific and Technical Information of China (English)

    LIAO Zi-li; MA Xiao-jun; ZHAO Yu-hui; ZANG Ke-mao

    2007-01-01

    The electric drive system characteristics of different projects for tracked vehicles are analyzed. For the two most typical projects, the parameters of power, torque and rotating speed and others of drive motor are figured out under the condition of satisfying adequate steering performance of the tracked vehicles. General opinions on the two projects are brought forward and conclusions are drawn.

  20. Fuzzy Control of Model Travel Tracking for Vehicle Semi-Active Suspension

    Institute of Scientific and Technical Information of China (English)

    GUAN Ji-fu; WU Yun-peng; GU Liang; HUANG Hua

    2006-01-01

    The control strategy of the model travel tracking for the vehicle suspension system is presented based on analyzing the responses of the vehicle suspension travel. A fuzzy control system of vehicle suspension is designed, in which the suspension travel output of the adaptive LQG control system is taken as the tracking objective. The simulation results prove that the suspension travel and vertical acceleration can be tracked simultaneously with the simple fuzzy controller,and the tracking effect of fuzzy control is better than that of the PID controller.

  1. Analyses and Simulation of Fuzzy Logic Control for Suspension System of a Track Vehicle

    Institute of Scientific and Technical Information of China (English)

    YU Yang; WEI Xue-xia; ZHANG Yong-fa

    2008-01-01

    The vibration caused by terrible road excitation affects the ride quality and safety of track vehicles. The vibration control of suspension systems is a very important factor for modern track vehicles. A fuzzy logic control for suspension system of a track vehicle is presented. A mechanical model and a system of differential equations of motion taking account of the mass of loading wheel are established. Then the fuzzy logic control is applied to control the vibration of suspension system of track vehicles for sine signal and random road surfaces. Numerical simulation shows that the maximum acceleration of suspension system can be reduced to 44% of the original value for sine signal road surface, and the mean square root of acceleration of suspension system can be reduced to 21% for random road surface. Therefore, the proposed fuzzy logic control is an efficient method for the suspension systems of track vehicles.

  2. Aerial video and ladar imagery fusion for persistent urban vehicle tracking

    Science.gov (United States)

    Cho, Peter; Greisokh, Daniel; Anderson, Hyrum; Sandland, Jessica; Knowlton, Robert

    2007-04-01

    We assess the impact of supplementing two-dimensional video with three-dimensional geometry for persistent vehicle tracking in complex urban environments. Using recent video data collected over a city with minimal terrain content, we first quantify erroneous sources of automated tracking termination and identify those which could be ameliorated by detailed height maps. They include imagery misregistration, roadway occlusion and vehicle deceleration. We next develop mathematical models to analyze the tracking value of spatial geometry knowledge in general and high resolution ladar imagery in particular. Simulation results demonstrate how 3D information could eliminate large numbers of false tracks passing through impenetrable structures. Spurious track rejection would permit Kalman filter coasting times to be significantly increased. Track lifetimes for vehicles occluded by trees and buildings as well as for cars slowing down at corners and intersections could consequently be prolonged. We find high resolution 3D imagery can ideally yield an 83% reduction in the rate of automated tracking failure.

  3. Multi-Perspective Vehicle Detection and Tracking: Challenges, Dataset, and Metrics

    DEFF Research Database (Denmark)

    Dueholm, Jacob Velling; Kristoffersen, Miklas Strøm; Satzoda, Ravi K.;

    2016-01-01

    The research community has shown significant improvements in both vision-based detection and tracking of vehicles, working towards a high level understanding of on-road maneuvers. Behaviors of surrounding vehicles in a highway environment is found as an interesting starting point, of why this dat......The research community has shown significant improvements in both vision-based detection and tracking of vehicles, working towards a high level understanding of on-road maneuvers. Behaviors of surrounding vehicles in a highway environment is found as an interesting starting point, of why...... purposes to be used as traditional detection and tracking, together with tracking of vehicles across perspectives. Each of the four perspectives have been annotated, resulting in more than 4000 bounding boxes in order to evaluate and compare novel methods....

  4. Long-Term Tracking of a Specific Vehicle Using Airborne Optical Camera Systems

    Science.gov (United States)

    Kurz, F.; Rosenbaum, D.; Runge, H.; Cerra, D.; Mattyus, G.; Reinartz, P.

    2016-06-01

    In this paper we present two low cost, airborne sensor systems capable of long-term vehicle tracking. Based on the properties of the sensors, a method for automatic real-time, long-term tracking of individual vehicles is presented. This combines the detection and tracking of the vehicle in low frame rate image sequences and applies the lagged Cell Transmission Model (CTM) to handle longer tracking outages occurring in complex traffic situations, e.g. tunnels. The CTM model uses the traffic conditions in the proximities of the target vehicle and estimates its motion to predict the position where it reappears. The method is validated on an airborne image sequence acquired from a helicopter. Several reference vehicles are tracked within a range of 500m in a complex urban traffic situation. An artificial tracking outage of 240m is simulated, which is handled by the CTM. For this, all the vehicles in the close proximity are automatically detected and tracked to estimate the basic density-flow relations of the CTM model. Finally, the real and simulated trajectories of the reference vehicles in the outage are compared showing good correspondence also in congested traffic situations.

  5. 49 CFR 214.521 - Flagging equipment for on-track roadway maintenance machines and hi-rail vehicles.

    Science.gov (United States)

    2010-10-01

    ... maintenance machines and hi-rail vehicles. 214.521 Section 214.521 Transportation Other Regulations Relating... WORKPLACE SAFETY On-Track Roadway Maintenance Machines and Hi-Rail Vehicles § 214.521 Flagging equipment for on-track roadway maintenance machines and hi-rail vehicles. Each on-track roadway maintenance...

  6. Real-time model for simulating a tracked vehicle on deformable soils

    Directory of Open Access Journals (Sweden)

    Martin Meywerk

    2016-05-01

    Full Text Available Simulation is one possibility to gain insight into the behaviour of tracked vehicles on deformable soils. A lot of publications are known on this topic, but most of the simulations described there cannot be run in real-time. The ability to run a simulation in real-time is necessary for driving simulators. This article describes an approach for real-time simulation of a tracked vehicle on deformable soils. The components of the real-time model are as follows: a conventional wheeled vehicle simulated in the Multi Body System software TRUCKSim, a geometric description of landscape, a track model and an interaction model between track and deformable soils based on Bekker theory and Janosi–Hanamoto, on one hand, and between track and vehicle wheels, on the other hand. Landscape, track model, soil model and the interaction are implemented in MATLAB/Simulink. The details of the real-time model are described in this article, and a detailed description of the Multi Body System part is omitted. Simulations with the real-time model are compared to measurements and to a detailed Multi Body System–finite element method model of a tracked vehicle. An application of the real-time model in a driving simulator is presented, in which 13 drivers assess the comfort of a passive and an active suspension of a tracked vehicle.

  7. Electric vehicle chassis dynamometer test methods at JPL and their correlation to track tests

    Science.gov (United States)

    Marte, J.; Bryant, J.

    1983-01-01

    Early in its electric vehicle (EV) test program, JPL recognized that EV test procedures were too vague and too loosely defined to permit much meaningful data to be obtained from the testing. Therefore, JPL adopted more stringent test procedures and chose the chassis dynamometer rather than the track as its principal test technique. Through the years, test procedures continued to evolve towards a methodology based on chassis dynamometers which would exhibit good correlation with track testing. Based on comparative dynamometer and track test results on the ETV-1 vehicle, the test methods discussed in this report demonstrate a means by which excellent track-to-dynamometer correlation can be obtained.

  8. Speed Tracking Control of a Vehicle Robot Driver System Using Multiple Sliding Surface Control Schemes

    Directory of Open Access Journals (Sweden)

    Gang Chen

    2013-02-01

    Full Text Available To overcome the drawbacks of using a traditional proportional-integral-derivative (PID control method for a robot driver system, such as requiring preliminary offline learning, big overshoot and large speed fluctuation, a new method for speed tracking of a robot driver system based on sliding mode control is proposed in this paper. Firstly, the coordinated control model of multiple manipulators for the robot driver is built, which achieved coordinated control of the throttle mechanical leg, clutch mechanical leg, brake mechanical leg and shift mechanical arm for the robot driver. On the basis of this, a speed tracking sliding mode controller for a vehicle robot driver is designed using the method of multiple sliding surfaces design, and the variable structure control laws of throttle and brake are designed respectively, which realize the speed tracking of the given driving test cycle. Experimental results demonstrate that compared with the PID control method, the proposed method can obviously reduce the overshoot of vehicle speed tracking control and greatly improve the accuracy of vehicle speed tracking. The vehicle speed tracking accuracy stays within a tolerance band of ±2 km/h, which meets the requirements of national vehicle test standards. Furthermore, the action of the speed tracking control in the same driving test cycle using the proposed method is consistent, so that the robot driver has good repeatability. Therefore, it can ensure the effectiveness of the vehicle emission test.

  9. Using Satellite-Based Earth Science Data in a Public Health Decision-Support System to Track and Forecast Pollen Events

    Science.gov (United States)

    Hudspeth, W. B.; Budge, A.

    2013-12-01

    There is widespread recognition within the public health community that ongoing changes in climate are expected to increasingly pose threats to human health. Environmentally induced health risks to populations with respiratory illnesses are a growing concern globally. Of particular concern are dust and smoke events carrying PM2.5 and PM10 particle sizes, ozone, and pollen. There is considerable interest in documenting the precise linkages between changing patterns in the climate and how these shifts impact the prevalence of respiratory illnesses. The establishment of these linkages can drive the development of early warning and forecasting systems to alert health care professionals of impending air-quality events. As a component of a larger NASA-funded project on Integration of Airborne Dust Prediction Systems and Vegetation Phenology to Track Pollen for Asthma Alerts in Public Health Decision Support Systems, the Earth Data Analysis Center (EDAC) at the University of New Mexico, is developing web-based visualization and analysis services for forecasting pollen concentration data. This decision-support system, New Mexico's Environmental Public Health Tracking System (NMEPHTS), funded by the Centers for Disease Control (CDC) Environmental Public Health Tracking Network (EPHTN), aims to improve health awareness and services by linking health effects data with levels and frequency of environmental exposure. The forecast of atmospheric events with high pollen concentrations has employed a modified version of the DREAM (Dust Regional Atmospheric Model, a verified model for atmospheric dust transport modeling. In this application, PREAM (Pollen Regional Atmospheric Model) models pollen emission using a MODIS-derived phenology of Juniperus spp. communities. Model outputs are verified and validated with ground-based records of pollen release timing and quantities. Outputs of the PREAM model are post-processed and archived in EDAC's Geographic Storage, Transformation, and

  10. A guidance and control algorithm for scent tracking micro-robotic vehicle swarms

    Energy Technology Data Exchange (ETDEWEB)

    Dohner, J.L. [Sandia National Labs., Albuquerque, NM (United States). Structural Dynamics Dept.

    1998-03-01

    Cooperative micro-robotic scent tracking vehicles are designed to collectively sniff out locations of high scent concentrations in unknown, geometrically complex environments. These vehicles are programmed with guidance and control algorithms that allow inter cooperation among vehicles. In this paper a cooperative guidance and control algorithm for scent tracking micro-robotic vehicles is presented. This algorithm is comprised of a sensory compensation sub-algorithm using point source cancellation, a guidance sub-algorithm using gradient descent tracking, and a control sub-algorithm using proportional feedback. The concepts of social rank and point source cancellation are new concepts introduced within. Simulation results for cooperative vehicles swarms are given. Limitations are discussed.

  11. Satellite vehicle tracking aiming to increase traffic safety within the Serbian Armed Forces

    Directory of Open Access Journals (Sweden)

    Igor S. Milanović

    2012-10-01

    Full Text Available The purpose of this work is to show how to affect the most important factor of traffic safety - an individual, by using some technical solutions of satellite tracking of vehicles. By using units of the Land Forces as an example, a brief analysis of traffic safety for vehicles less than 5 years old has been performed. It is noticed that the number of traffic accidents with these vehicles involved has increased, so we tried to use one software package commercially available in order to show all advantages and disadvantages which could be noticed during this kind of vehicle tracking. The conclusion is that preventive vehicle tracking can improve traffic safety, but that a techno-economic analysis has to be done as well, in order to create all the necessary conditions for the introduction of this system in the units of the Serbian Armed Forces.

  12. Implementation of an Onboard Visual Tracking System with Small Unmanned Aerial Vehicle (UAV)

    CERN Document Server

    Qadir, Ashraf; Neubert, Jeremiah

    2012-01-01

    This paper presents a visual tracking system that is capable or running real time on-board a small UAV (Unmanned Aerial Vehicle). The tracking system is computationally efficient and invariant to lighting changes and rotation of the object or the camera. Detection and tracking is autonomously carried out on the payload computer and there are two different methods for creation of the image patches. The first method starts detecting and tracking using a stored image patch created prior to flight with previous flight data. The second method allows the operator on the ground to select the interest object for the UAV to track. The tracking system is capable of re-detecting the object of interest in the events of tracking failure. Performance of the tracking system was verified both in the lab and during actual flights of the UAV. Results show that the system can run on-board and track a diverse set of objects in real time.

  13. Coupled Finite Element/Boundary Element Analysis of a Vehicle Moving Along a Railway Track

    DEFF Research Database (Denmark)

    Andersen, Lars; Nielsen, Søren R. K.

    2004-01-01

    Trains running in build-up areas are a source to ground-borne noise. A careful design of the track structure may be one way of minimizing the vibrations in the surroundings. For example, open or in-filled trenches may be constructed along the track, or the soil underneath the track may be improved....... In this work, analyses are carried out with the aim of investigating the influence of the track design and properties on the level of ground vibration due to a vehicle moving with subsonic speed. A coupled finite element and boundary element model of the track and subsoil is employed, adopting a formulation...... in the moving frame of reference following the vehicle. The computations are carried out in the frequency domain, and various combinations of the vehicle speed and the excitation frequency are analysed. The analyses indicate that open trenches are generally more efficient than in-filled trenches or soil...

  14. Challenges in the Tracking and Prediction of Scheduled-Vehicle Journeys

    DEFF Research Database (Denmark)

    Jensen, Christian Søndergaard; Tiesyte, Dalia

    2007-01-01

    this type of knowledge with minimal cost. This paper characterizes the problem of real-time vehicle tracking using wireless communication, and of predicting the future status of the vehicles when their movements are restricted to given routes and when they follow schedules with a best effort. The paper...... discusses challenges related to tracking, to the prediction of future travel times, and to historical data analysis. It also suggests approaches to addressing the challenges....

  15. Lane Changing Trajectory Planning and Tracking Controller Design for Intelligent Vehicle Running on Curved Road

    Directory of Open Access Journals (Sweden)

    Lie Guo

    2014-01-01

    Full Text Available To enhance the active safety and realize the autonomy of intelligent vehicle on highway curved road, a lane changing trajectory is planned and tracked for lane changing maneuver on curved road. The kinematics model of the intelligent vehicle with nonholonomic constraint feature and the tracking error model are established firstly. The longitudinal and lateral coupling and the difference of curvature radius between the outside and inside lane are taken into account, which is helpful to enhance the authenticity of desired lane changing trajectory on curved road. Then the trajectory tracking controller of closed-loop control structure is derived using integral backstepping method to construct a new virtual variable. The Lyapunov theory is applied to analyze the stability of the proposed tracking controller. Simulation results demonstrate that this controller can guarantee the convergences of both the relative position tracking errors and the position tracking synchronization.

  16. Probabilistic Tracking and Trajectory Planning for Autonomous Ground Vehicles in Urban Environments

    Science.gov (United States)

    2016-03-05

    SECURITY CLASSIFICATION OF: The aim of this research is to develop a unified theory for perception and planning in autonomous ground vehicles , with a...Pine Tree Road Ithaca, NY 14850 -2820 ABSTRACT Probabilistic Tracking and Trajectory Planning for Autonomous Ground Vehicles in Urban Environments...Report Title The aim of this research is to develop a unified theory for perception and planning in autonomous ground vehicles , with a specific focus on

  17. A study on the nondestructive test optimum design for a ground tracked combat vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Kim Byeong Ho; Seo, Jae Hyun; Gil, Hyeon Jun [Defence Agency for Technology and Quality, Seoul (Korea, Republic of); Kim, Seon Hyeong [Hanwha Techwin Co.,Ltd., Changwon (Korea, Republic of); Seo, Sang Chul [Changwon National University, Changwon (Korea, Republic of)

    2015-10-15

    In this study, a nondestructive test (NDT) is performed to inspect the optimal design of a ground tracked combat vehicle for self-propelled artillery, tank, and armored vehicles. The minimum qualification required for personnel performing the NDT of a ground tracked combat vehicle was initially established in US military standards, and then applied to the Korean defense specifications to develop a ground tracked combat vehicle. However, the qualification standards of an NDT inspector have been integrated into NAS410 through the military and commercial specifications unification project that were applied in the existing aerospace/defense industry public standard. The design method for this study was verified by applying the optimal design to the liquid penetrant testing Al forging used in self-propelled artillery. This confirmed the reliability and soundness of the product.

  18. 49 CFR 214.525 - Towing with on-track roadway maintenance machines or hi-rail vehicles.

    Science.gov (United States)

    2010-10-01

    ... or hi-rail vehicles. 214.525 Section 214.525 Transportation Other Regulations Relating to... SAFETY On-Track Roadway Maintenance Machines and Hi-Rail Vehicles § 214.525 Towing with on-track roadway maintenance machines or hi-rail vehicles. (a) When used to tow pushcars or other maintenance-of-way...

  19. Effect of rail corrugation on vertical dynamics of railway vehicle coupled with a track

    Institute of Scientific and Technical Information of China (English)

    Xuesong Jin; Kaiyun Wang; Zefeng Wen; Weihua Zhang

    2005-01-01

    The effect of rail corrugation on the vertical dynamics of railway vehicle coupled with a curved track is investigated in detail with a numerical method when a wheelset is steadily curving. In the calculation of rail corrugation we consider the combination of Kalker's rolling contact theory modified, a model of material loss on rail running surface, and a dynamics model of railway vehicle coupled with a curved track. In the establishment of the dynamic model, for simplicity, one fourth of the freight car without lateral motions,namely a wheelset and the equivalent one fourth freight car body above it, is considered. The Euler beam is used to model the rails and the track structure under the rails is replaced with equivalent springs, dampers and mass bodies. The numerical results show the great influence of the rail corrugation on the vibration of the parts of the vehicle and the track, and the some characters of rail corrugation in development.

  20. Perspectives on railway track geometry condition monitoring from in-service railway vehicles

    Science.gov (United States)

    Weston, P.; Roberts, C.; Yeo, G.; Stewart, E.

    2015-07-01

    This paper presents a view of the current state of monitoring track geometry condition from in-service vehicles. It considers technology used to provide condition monitoring; some issues of processing and the determination of location; how things have evolved over the past decade; and what is being, or could/should be done in future research. Monitoring railway track geometry from an in-service vehicle is an attractive proposition that has become a reality in the past decade. However, this is only the beginning. Seeing the same track over and over again provides an opportunity for observing track geometry degradation that can potentially be used to inform maintenance decisions. Furthermore, it is possible to extend the use of track condition information to identify if maintenance is effective, and to monitor the degradation of individual faults such as dipped joints. There are full unattended track geometry measurement systems running on in-service vehicles in the UK and elsewhere around the world, feeding their geometry measurements into large databases. These data can be retrieved, but little is currently done with the data other than the generation of reports of track geometry that exceeds predefined thresholds. There are examples of simpler systems that measure some track geometry parameters more or less directly and accurately, but forego parameters such as gauge. Additionally, there are experimental systems that use mathematics and models to infer track geometry using data from sensors placed on an in-service vehicle. Finally, there are systems that do not claim to measure track geometry, but monitor some other quantity such as ride quality or bogie acceleration to infer poor track geometry without explicitly measuring it.

  1. Impact of mesh tracks and low-ground-pressure vehicle use on blanket peat hydrology

    Science.gov (United States)

    McKendrick-Smith, Kathryn; Holden, Joseph; Parry, Lauren

    2016-04-01

    Peatlands are subject to multiple uses including drainage, farming and recreation. Low-ground-pressure vehicle access is desirable by land owners and tracks facilitate access. However, there is concern that such activity may impact peat hydrology and so granting permission for track installation has been problematic, particularly without evidence for decision-making. We present the first comprehensive study of mesh track and low-ground-pressure vehicle impacts on peatland hydrology. In the sub-arctic oceanic climate of the Moor House World Biosphere Reserve in the North Pennines, UK, a 1.5 km long experimental track was installed to investigate hydrological impacts. Surface vegetation was cut and the plastic mesh track pinned into the peat surface. The experimental track was split into 7 treatments, designed to reflect typical track usage (0 - 5 vehicle passes per week) and varying vehicle weight. The greatest hydrological impacts were expected for sections of track subject to more frequent vehicle use and in close proximity to the track. In total 554 dipwells (including 15 automated recording at 15-min intervals) were monitored for water-table depth, positioned to capture potential spatial variability in response. Before track installation, samples for vertical and lateral hydraulic conductivity (Ks) analysis (using the modified cube method) were taken at 0-10 cm depth from a frequently driven treatment (n = 15), an infrequently driven treatment (0.5 passes per week) (n = 15) and a control site with no track/driving (n = 15). The test was repeated after 16 months of track use. We present a spatially and temporally rich water-table dataset from the study site showing how the impacts of the track on water table are spatially highly variable. Water-table depths across the site were shallow, typically within the upper 10 cm of the peat profile for > 75% of the time. We show that mesh track and low-ground-pressure vehicle impacts on water-table depth were small except

  2. A novel model for determining the amplitude-wavelength limits of track irregularities accompanied by a reliability assessment in railway vehicle-track dynamics

    Science.gov (United States)

    Xu, Lei; Zhai, Wanming

    2017-03-01

    The loads on a vehicle and the vibrations transmitted to track infrastructures due to the operation of rolling stocks are mainly determined by the irregularities of the track profile. Hence, it is rather important to ascertain the limits of track irregularities, including amplitudes and wavelengths, to guarantee the dynamic performance of running vehicles and guiding tracks. Furthermore, the operation and management levels as well as irregularity status for different railways are highly dissimilar. Therefore, it is a necessary to conduct a reliability assessment for a specific railway line. In the present work, a large amount of measured track irregularities are concentrated as a group form of the track irregularity power spectrum density. A track irregularity inversion model is presented to obtain realistic representations of track profile deformations with information regarding amplitudes, wavelengths and probabilities. Then, the methodologies for determining the limits of track irregularities and achieving a reliability assessment are presented by introducing the probability density evolution method and development of a Wavelet-Wigner-Hough method. Using the vehicle-track interaction model, numerical studies for confirming the limits of track irregularities and evaluating the reliability of the dynamic performance of the vehicle can be conducted to provide valuable suggestions. This paper offers new possibilities for studying the limit amplitudes, characteristic wavelengths of track irregularities as well as corresponding reliabilities when a railway vehicle runs under different track geometric conditions.

  3. Vehicle Tracking for an Evasive Manoeuvres Assistant Using Low-Cost Ultrasonic Sensors

    Directory of Open Access Journals (Sweden)

    Felipe Jiménez

    2014-11-01

    Full Text Available Many driver assistance systems require knowledge of the vehicle environment. As these systems are increasing in complexity and performance, this knowledge of the environment needs to be more complete and reliable, so sensor fusion combining long, medium and short range sensors is now being used. This paper analyzes the feasibility of using ultrasonic sensors for low cost vehicle-positioning and tracking in the lane adjacent to the host vehicle in order to identify free areas around the vehicle and provide information to an automatic avoidance collision system that can perform autonomous braking and lane change manoeuvres. A laser scanner is used for the early detection of obstacles in the direction of travel while two ultrasonic sensors monitor the blind spot of the host vehicle. The results of tests on a test track demonstrate the ability of these sensors to accurately determine the kinematic variables of the obstacles encountered, despite a clear limitation in range.

  4. Vehicle tracking for an evasive manoeuvres assistant using low-cost ultrasonic sensors.

    Science.gov (United States)

    Jiménez, Felipe; Naranjo, José E; Gómez, Oscar; Anaya, José J

    2014-11-28

    Many driver assistance systems require knowledge of the vehicle environment. As these systems are increasing in complexity and performance, this knowledge of the environment needs to be more complete and reliable, so sensor fusion combining long, medium and short range sensors is now being used. This paper analyzes the feasibility of using ultrasonic sensors for low cost vehicle-positioning and tracking in the lane adjacent to the host vehicle in order to identify free areas around the vehicle and provide information to an automatic avoidance collision system that can perform autonomous braking and lane change manoeuvres. A laser scanner is used for the early detection of obstacles in the direction of travel while two ultrasonic sensors monitor the blind spot of the host vehicle. The results of tests on a test track demonstrate the ability of these sensors to accurately determine the kinematic variables of the obstacles encountered, despite a clear limitation in range.

  5. Coupled Finite Element/Boundary Element Analysis of a Vehicle Moving Along a Railway Track

    DEFF Research Database (Denmark)

    Andersen, Lars; Nielsen, Søren R. K.

    2004-01-01

    Trains running in build-up areas are a source to ground-borne noise. A careful design of the track structure may be one way of minimizing the vibrations in the surroundings. For example, open or in-filled trenches may be constructed along the track, or the soil underneath the track may be improved....... In this work, analyses are carried out with the aim of investigating the influence of the track design and properties on the level of ground vibration due to a vehicle moving with subsonic speed. A coupled finite element and boundary element model of the track and subsoil is employed, adopting a formulation...... stiffening?even at low frequencies. However, for high-speed vehicles rubber chip barriers may be a promising means of vibration screening...

  6. Platform Independent Launch Vehicle Avionics with GPS Metric Tracking Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For this award, Tyvak proposes to develop a complete suite of avionics for a Nano-Launch Vehicle (NLV) based on the architecture determinations performed during...

  7. Collaborative multi-target tracking using networked micro-robotic vehicles

    Science.gov (United States)

    Biswas, Subir; Gupta, Sonny; Yu, Fan; Wu, Tao

    2007-04-01

    This paper presents a collaborative target tracking framework, in which distributed mechanisms are developed for tracking multiple mobile targets using a team of networked micro robotic vehicles. Applications of such a framework would include detection of multi-agent intrusion, network-assisted attack localization, and other collaborative search scenarios. The key idea of the developed framework is to design distributed algorithms that can be executed by tracking entities using a mobile ad hoc network. The paper comprises the following components. First, the software and hardware architectural detail of a Swarm Capable Autonomous Vehicle (SCAV) system that is used as the mobile platform in our target tracking application is presented. Second, the details of an indoor self-localization and Kalman filter based navigation system for the SCAV are presented. Third, a formal definition of the collaborative multi-target tracking problem and a heuristic based networked solution are developed. Finally, the performance of the proposed tracking framework is evaluated on a laboratory test-bed of a fleet of SCAV vehicles. A detailed system characterization in terms localization, navigation, and collaborative tracking performance is performed on the SCAV test-bed. In addition to valuable implementation insights about the localization, navigation, filtering, and ad hoc networking processes, a number of interesting conclusions about the overall tracking system are presented.

  8. Experimental Research on Jerk Characteristics of Tracked Vehicles at Starting Phase

    Institute of Scientific and Technical Information of China (English)

    LIU Hai-ou; CHEN Hui-yan; ZHAI Yong

    2005-01-01

    Based on detailed analysis of vehicle dynamics, the theoretical jerk characteristics of tracked vehicles at starting phase are expressed. The experimental research on jerk characteristics under different control parameters is carried out during main clutch engaging process of AMT vehicles in terms of acceleration measurement. The test results show jerk calculated from acceleration signal is convincing and basically consistent with the subjective feeling of passengers. And the test results have practical value for the objective evaluation and the improvement of starting smoothness of AMT vehicles.

  9. Research and Development of Engine-Generator Set Control System for Tracked Vehicle Electric Transmission System

    Institute of Scientific and Technical Information of China (English)

    HUANG Ying; HUANG Qian; SUN Feng-chun; LIU Bo-lan; LIU Jia

    2007-01-01

    As an energy generating equipment, the engine-generator set supplies power to the electric transmission. Therefore, its control is one of the key technologies of electric vehicles. Based on the discussion about the demands to the engine-generator set in tracked vehicles, the detailed function of engine-generator and the control strategy are determined. The hardware and software of the control system are also developed and tested in a prototype vehicle. The experiment results show that the control system has good reliability and can satisfy the power requirements of vehicles under all operating conditions.

  10. Investigation of Control Algorithms for Tracked Vehicle Mobility Load Emulation for a Combat Hybrid Electric Power System

    Science.gov (United States)

    2009-07-30

    Investigation of Control Algorithms for Tracked Vehicle Mobility Load Emulation for a Combat Hybrid Electric Power System Jarrett Goodell and...TITLE AND SUBTITLE Investigation of Control Algorithms for Tracked Vehicle Mobility Load Emulation for a Combat Hybrid Electric Power System 5a...for ~ 22 ton tracked vehicle • Tested and Developed: – Motors, Generators, Batteries, Inverters, DC-DC Converters , Thermal Management, Pulse Power

  11. ASSESSMENT OF LEVITATION MOVEMENT ELECTRODYNAMIC VEHICLES IN DIFFERENT POSITIONS OF THE CONTOURS OF THE FLAT TRACK CONSTRUCTION

    Directory of Open Access Journals (Sweden)

    N. O. Radchenko

    2010-02-01

    Full Text Available The results of investigation of spatial oscillations and stability of motion of electrodynamically levitated vehicle are presented. Various shapes of the track contours and their arrangement on a plain track structure are considered

  12. Tracks for Eastern/Western European Future Launch Vehicles Cooperation

    Science.gov (United States)

    Eymar, Patrick; Bertschi, Markus

    2002-01-01

    exclusively upon Western European elements indigenously produced. Yet some private initiatives took place successfully in the second half of the nineties (Eurockot and Starsem) bringing together companies from Western and Eastern Europe. Evolution of these JV's are already envisioned. But these ventures relied mostly on already existing vehicles. broadening the bases in order to enlarge the reachable world market appears attractive, even if structural difficulties are complicating the process. had recently started to analyze, with KSRC counterparts how mixing Russian and Western European based elements would provide potential competitive edges. and RKA in the frame of the new ESA's Future Launch Preparatory Programme (FLPP). main technical which have been considered as the most promising (reusable LOx/Hydrocarbon engine, experimental reentry vehicles or demonstrators and reusable launch vehicle first stage or booster. international approach. 1 patrick.eymar@lanceurs.aeromatra.com 2

  13. Video Tracking for Visual Degraded Aerial Vehicle with H-PMHT

    Directory of Open Access Journals (Sweden)

    A. G. Pakfiliz

    2015-12-01

    Full Text Available The work presented in this paper describes a novel approach for automatic video tracking of visual degraded air vehicles in daylight with sky background. The offered and applied video object tracking method is based on Histogram Probabilistic Multi Hypothesis Tracker algorithm. The H-PMHT is an expectation maximization based algorithm developed for tracking objects in intense clutter environment by using intensity modulated data streams. Basically H-PMHT algorithm is suitable for linear-Gaussian point spread function case. However, recent studies have indicated that the algorithm is also applicable for non-linear and non-Gaussian target shapes. Thus H-PMHT becomes a suitable alternative for tracking applications with sonar, high resolution radars,IR, UV sensors and cameras. In this work H-PMHT algorithm is used for video tracking of visual degraded air vehicles. For this purpose RGB video data is processed by using a reciprocal pixel intensity measurement for meeting the requirements of the tracking process. A simulation study is conducted in order to demonstrate the video tracking performance of H-PMHT against visual degraded air vehicles. Also the results obtained with H-PMHT algorithm are compared with the results of amplitude information added Interacting Multi Model Probabilistic Data Association algorithm.

  14. Challenges in the Tracking and Prediction of Scheduled-Vehicle Journeys

    DEFF Research Database (Denmark)

    Jensen, Christian Søndergaard; Tiesyte, Dalia

    2007-01-01

    A number of applications in areas such as logistics, cargo delivery, and collective transport involve the management of fleets of vehicles that are expected to travel along known routes according to fixed schedules. Due to road construction, accidents, and other unanticipated conditions......, the vehicles deviate from their schedules. At the same time, there is a need for the infrastructure surrounding the vehicles to continually know the actual status of the vehicles. For example, anticipated arrival times of buses may have to be displayed at bus stops. It is a fundamental challenge to maintain...... this type of knowledge with minimal cost. This paper characterizes the problem of real-time vehicle tracking using wireless communication, and of predicting the future status of the vehicles when their movements are restricted to given routes and when they follow schedules with a best effort. The paper...

  15. Steering Dynamic Performance of an Electric Transmission Tracked Vehicle Based on Rotating Speed Control

    Institute of Scientific and Technical Information of China (English)

    SUN Feng-chun; CHEN Shu-yong; ZHANG Cheng-ning

    2006-01-01

    In order to analyze steering dynamic performance of an electric transmission tracked vehicle exactly, modern design theory and methodology-collaborative simulation and virtual prototype are applied. The 3-D multi-body dynamic model of full vehicle running gears and control system model are built based on the simulation platform on dynamic analysis software known as RecurDyn/Track-HM and control system analysis software known as Matlab/Simulink. Theory analysis and collaborative simulation of turning kinematic/dynamic performance in different velocity and turning radius are made. Comparing the test result with theory computation validates the correctness of the model. The method has instructional significance of solving the existent modeling problem, comprehension of turning performance and test debugging strategy,and also forms a new idea of research on dynamic characteristics for the electric transmission tracked vehicle's electric propulsion system.

  16. Two Algorithms for the Detection and Tracking of Moving Vehicle Targets in Aerial Infrared Image Sequences

    Directory of Open Access Journals (Sweden)

    Yutian Cao

    2015-12-01

    Full Text Available In this paper, by analyzing the characteristics of infrared moving targets, a Symmetric Frame Differencing Target Detection algorithm based on local clustering segmentation is proposed. In consideration of the high real-time performance and accuracy of traditional symmetric differencing, this novel algorithm uses local grayscale clustering to accomplish target detection after carrying out symmetric frame differencing to locate the regions of change. In addition, the mean shift tracking algorithm is also improved to solve the problem of missed targets caused by error convergence. As a result, a kernel-based mean shift target tracking algorithm based on detection updates is also proposed. This tracking algorithm makes use of the interaction between detection and tracking to correct the tracking errors in real time and to realize robust target tracking in complex scenes. In addition, the validity, robustness and stability of the proposed algorithms are all verified by experiments on mid-infrared aerial sequences with vehicles as targets.

  17. Vehicle tracking in wide area motion imagery from an airborne platform

    Science.gov (United States)

    van Eekeren, Adam W. M.; van Huis, Jasper R.; Eendebak, Pieter T.; Baan, Jan

    2015-10-01

    Airborne platforms, such as UAV's, with Wide Area Motion Imagery (WAMI) sensors can cover multiple square kilometers and produce large amounts of video data. Analyzing all data for information need purposes becomes increasingly labor-intensive for an image analyst. Furthermore, the capacity of the datalink in operational areas may be inadequate to transfer all data to the ground station. Automatic detection and tracking of people and vehicles enables to send only the most relevant footage to the ground station and assists the image analysts in effective data searches. In this paper, we propose a method for detecting and tracking vehicles in high-resolution WAMI images from a moving airborne platform. For the vehicle detection we use a cascaded set of classifiers, using an Adaboost training algorithm on Haar features. This detector works on individual images and therefore does not depend on image motion stabilization. For the vehicle tracking we use a local template matching algorithm. This approach has two advantages. In the first place, it does not depend on image motion stabilization and it counters the inaccuracy of the GPS data that is embedded in the video data. In the second place, it can find matches when the vehicle detector would miss a certain detection. This results in long tracks even when the imagery is of low frame-rate. In order to minimize false detections, we also integrate height information from a 3D reconstruction that is created from the same images. By using the locations of buildings and roads, we are able to filter out false detections and increase the performance of the tracker. In this paper we show that the vehicle tracks can also be used to detect more complex events, such as traffic jams and fast moving vehicles. This enables the image analyst to do a faster and more effective search of the data.

  18. Observer-based linear parameter varying H∞ tracking control for hypersonic vehicles

    Directory of Open Access Journals (Sweden)

    Yiqing Huang

    2016-11-01

    Full Text Available This article aims to develop observer-based linear parameter varying output feedback H∞ tracking controller for hypersonic vehicles. Due to the complexity of an original nonlinear model of the hypersonic vehicle dynamics, a slow–fast loop linear parameter varying polytopic model is introduced for system stability analysis and controller design. Then, a state observer is developed by linear parameter varying technique in order to estimate the unmeasured attitude angular for slow loop system. Also, based on the designed linear parameter varying state observer, a kind of attitude tracking controller is presented to reduce tracking errors for all bounded reference attitude angular inputs. The closed-loop linear parameter varying system is proved to be quadratically stable by Lypapunov function technique. Finally, simulation results show that the developed linear parameter varying H∞ controller has good tracking capability for reference commands.

  19. The prediction technology study of fatigue life for key parts of a tracked vehicle's suspension system

    Institute of Scientific and Technical Information of China (English)

    WANG Hongyan; RUI Qiang; HE Xiaojun

    2007-01-01

    In allusion to fatigue life of a tracked vehicle torsion bar, a virtual prototype model of the tracked vehicle suspension system including a flexible torsion bar was built based on dynamic simulation software-ADAMS. Node force and stress results of the torsion bar from last step simu- lation were acquired; taking into account the material charac- teristics and influential factors, fatigue life of the flexible body. of the torsion bar was predicted. Engineering results can be acquired through the contrast of the result of virtual test and statistical fatigue.

  20. DOE Phase II SBIR: Spectrally-Assisted Vehicle Tracking - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Villeneuve, Pierre V. [Space Computer Corporation

    2013-02-28

    The goal of this Phase II SBIR has been to develop a prototype software package to demonstrate spectrally-aided vehicle tracking. The primary application is to show improved target vehicle tracking performance in complex environments where traditional spatial tracker systems may show reduced performance. Examples include scenarios where the target vehicle is obscured by a large structure for an extended period of time, or where the target is engaging in extreme maneuvers amongst other civilian vehicles. The target information derived from spatial processing is unable to differentiate between the green versus the red vehicle. Spectral signature exploitation enables comparison of new candidate targets with existing track signatures. The ambiguity in this confusing scenario is resolved by folding spectral analysis results into each target nomination and association processes. The work performed over the two-year effort was divided into three general areas: algorithm refinement, software prototype development, and prototype performance demonstration. The tasks performed under this Phase II resulted in the completion of a software tool suitable for evaluation and testing of advanced tracking concepts.

  1. Numerical simulation of active track tensioning system for autonomous hybrid vehicle

    Science.gov (United States)

    Mȩżyk, Arkadiusz; Czapla, Tomasz; Klein, Wojciech; Mura, Gabriel

    2017-05-01

    One of the most important components of a high speed tracked vehicle is an efficient suspension system. The vehicle should be able to operate both in rough terrain for performance of engineering tasks as well as on the road with high speed. This is especially important for an autonomous platform that operates either with or without human supervision, so that the vibration level can rise compared to a manned vehicle. In this case critical electronic and electric parts must be protected to ensure the reliability of the vehicle. The paper presents a dynamic parameters determination methodology of suspension system for an autonomous high speed tracked platform with total weight of about 5 tonnes and hybrid propulsion system. Common among tracked vehicles suspension solutions and cost-efficient, the torsion-bar system was chosen. One of the most important issues was determining optimal track tensioning - in this case an active hydraulic system was applied. The selection of system parameters was performed with using numerical model based on multi-body dynamic approach. The results of numerical analysis were used to define parameters of active tensioning control system setup. LMS Virtual.Lab Motion was used for multi-body dynamics numerical calculation and Matlab/SIMULINK for control system simulation.

  2. Autonomous & Adaptive Oceanographic Feature Tracking on Board Autonomous Underwater Vehicles

    Science.gov (United States)

    2015-02-01

    vehicles, riding dirt bikes in her backyard, and learning languages. Stephanie earned her Bachelor of Science Degree in Aerospace Engineering with a...Kalina, and Heather as my engineering friends who suffered through quals and classes with me in our first few years. I also owe a huge thanks to my family ...food supplies, and coastal human populations . Although a large portion of oil rises to the surface during a spill event to form a slick, over time (on

  3. The Integration of GPS Navigator Device with Vehicles Tracking System for Rental Cars Firms

    OpenAIRE

    Omarah O. Alharaki; Fahad S. Alaieri; Akram M. Zeki

    2010-01-01

    The aim of this research is to integrate the GPS tracking system (tracking device and web-based application) with GPS navigator for rental cars, allowing the company to use various applications to monitor and manage the cars. This is enable the firms and customers to communicate with each other via the GPS navigator. The system should be developed by applying new features in GPS tracking application devices in vehicles. This paper also proposes new features that can be applied to the GPS Navi...

  4. Vector Pursuit Path Tracking for Autonomous Ground Vehicles

    Science.gov (United States)

    2000-08-01

    collision avoidance for a mobile robot,” Robotica , v12, 1994, p521-527. [30] Saffiotti, A., Ruspini, E. H. and Konolige, K., “Blending Reactivity and...based collision avoidance for a mobile robot,” Robotica , v15, 1997, p627-632. [43] Hoffman, F. and Pfister, G., “Evolutionary Design of a Fuzzy...DeSantis, R. M., “Modeling and path-tracking control of a mobile wheeled robot with a differential drive,” Robotica , v13, 1995, p401-410. [49

  5. Design and Implementation of Browser based GPS/GPRS Vehicle Positioning and Tracking System

    Directory of Open Access Journals (Sweden)

    Zhang Keqiang

    2015-01-01

    Full Text Available This paper mainly describes a vehicle positioning and tracking system which is based on browser, GPS and GPRS. And this system takes advantage of Baidu Map as basic material to show vehicle status, which enables drivers and supervisor to monitor the vehicle’s current and past positions. The vehicle’s location data is got from satellites, and these data is sent to the central server through GPRS, the central server will store formatted data into the database after the data is parsed; Later, these data stored in the database will be used by web application and displayed on the map as markers. This paper also involves the implementation on mobile side, and this system used Baidu map JavaScript interface, Ajax, JSP and JSON to implement the vehicle positioning and tracking system.

  6. Subsea Cable Tracking by Autonomous Underwater Vehicle with Magnetic Sensing Guidance.

    Science.gov (United States)

    Xiang, Xianbo; Yu, Caoyang; Niu, Zemin; Zhang, Qin

    2016-08-20

    The changes of the seabed environment caused by a natural disaster or human activities dramatically affect the life span of the subsea buried cable. It is essential to track the cable route in order to inspect the condition of the buried cable and protect its surviving seabed environment. The magnetic sensor is instrumental in guiding the remotely-operated vehicle (ROV) to track and inspect the buried cable underseas. In this paper, a novel framework integrating the underwater cable localization method with the magnetic guidance and control algorithm is proposed, in order to enable the automatic cable tracking by a three-degrees-of-freedom (3-DOF) under-actuated autonomous underwater vehicle (AUV) without human beings in the loop. The work relies on the passive magnetic sensing method to localize the subsea cable by using two tri-axial magnetometers, and a new analytic formulation is presented to compute the heading deviation, horizontal offset and buried depth of the cable. With the magnetic localization, the cable tracking and inspection mission is elaborately constructed as a straight-line path following control problem in the horizontal plane. A dedicated magnetic line-of-sight (LOS) guidance is built based on the relative geometric relationship between the vehicle and the cable, and the feedback linearizing technique is adopted to design a simplified cable tracking controller considering the side-slip effects, such that the under-actuated vehicle is able to move towards the subsea cable and then inspect its buried environment, which further guides the environmental protection of the cable by setting prohibited fishing/anchoring zones and increasing the buried depth. Finally, numerical simulation results show the effectiveness of the proposed magnetic guidance and control algorithm on the envisioned subsea cable tracking and the potential protection of the seabed environment along the cable route.

  7. Subsea Cable Tracking by Autonomous Underwater Vehicle with Magnetic Sensing Guidance

    Directory of Open Access Journals (Sweden)

    Xianbo Xiang

    2016-08-01

    Full Text Available The changes of the seabed environment caused by a natural disaster or human activities dramatically affect the life span of the subsea buried cable. It is essential to track the cable route in order to inspect the condition of the buried cable and protect its surviving seabed environment. The magnetic sensor is instrumental in guiding the remotely-operated vehicle (ROV to track and inspect the buried cable underseas. In this paper, a novel framework integrating the underwater cable localization method with the magnetic guidance and control algorithm is proposed, in order to enable the automatic cable tracking by a three-degrees-of-freedom (3-DOF under-actuated autonomous underwater vehicle (AUV without human beings in the loop. The work relies on the passive magnetic sensing method to localize the subsea cable by using two tri-axial magnetometers, and a new analytic formulation is presented to compute the heading deviation, horizontal offset and buried depth of the cable. With the magnetic localization, the cable tracking and inspection mission is elaborately constructed as a straight-line path following control problem in the horizontal plane. A dedicated magnetic line-of-sight (LOS guidance is built based on the relative geometric relationship between the vehicle and the cable, and the feedback linearizing technique is adopted to design a simplified cable tracking controller considering the side-slip effects, such that the under-actuated vehicle is able to move towards the subsea cable and then inspect its buried environment, which further guides the environmental protection of the cable by setting prohibited fishing/anchoring zones and increasing the buried depth. Finally, numerical simulation results show the effectiveness of the proposed magnetic guidance and control algorithm on the envisioned subsea cable tracking and the potential protection of the seabed environment along the cable route.

  8. Preceding Vehicle Detection and Tracking Adaptive to Illumination Variation in Night Traffic Scenes Based on Relevance Analysis

    Directory of Open Access Journals (Sweden)

    Junbin Guo

    2014-08-01

    Full Text Available Preceding vehicle detection and tracking at nighttime are challenging problems due to the disturbance of other extraneous illuminant sources coexisting with the vehicle lights. To improve the detection accuracy and robustness of vehicle detection, a novel method for vehicle detection and tracking at nighttime is proposed in this paper. The characteristics of taillights in the gray level are applied to determine the lower boundary of the threshold for taillights segmentation, and the optimal threshold for taillight segmentation is calculated using the OTSU algorithm between the lower boundary and the highest grayscale of the region of interest. The candidate taillight pairs are extracted based on the similarity between left and right taillights, and the non-vehicle taillight pairs are removed based on the relevance analysis of vehicle location between frames. To reduce the false negative rate of vehicle detection, a vehicle tracking method based on taillights estimation is applied. The taillight spot candidate is sought in the region predicted by Kalman filtering, and the disturbed taillight is estimated based on the symmetry and location of the other taillight of the same vehicle. Vehicle tracking is completed after estimating its location according to the two taillight spots. The results of experiments on a vehicle platform indicate that the proposed method could detect vehicles quickly, correctly and robustly in the actual traffic environments with illumination variation.

  9. Pressure tracking control of vehicle ABS using piezo valve modulator

    Science.gov (United States)

    Jeon, Juncheol; Choi, Seung-Bok

    2011-03-01

    This paper presents a wheel slip control for the ABS(anti-lock brake system) of a passenger vehicle using a controllable piezo valve modulator. The ABS is designed to optimize for braking effectiveness and good steerability. As a first step, the principal design parameters of the piezo valve and pressure modulator are appropriately determined by considering the braking pressure variation during the ABS operation. The proposed piezo valve consists of a flapper, pneumatic circuit and a piezostack actuator. In order to get wide control range of the pressure, the pressure modulator is desired. The modulator consists of a dual-type cylinder filled with different substances (fluid and gas) and a piston rod moving vertical axis to transmit the force. Subsequently, a quarter car wheel slip model is formulated and integrated with the governing equation of the piezo valve modulator. A sliding mode controller to achieve the desired slip rate is then designed and implemented. Braking control performances such as brake pressure and slip rate are evaluated via computer simulations.

  10. Investigating the Mobility of Light Autonomous Tracked Vehicles using a High Performance Computing Simulation Capability

    Science.gov (United States)

    Negrut, Dan; Mazhar, Hammad; Melanz, Daniel; Lamb, David; Jayakumar, Paramsothy; Letherwood, Michael; Jain, Abhinandan; Quadrelli, Marco

    2012-01-01

    This paper is concerned with the physics-based simulation of light tracked vehicles operating on rough deformable terrain. The focus is on small autonomous vehicles, which weigh less than 100 lb and move on deformable and rough terrain that is feature rich and no longer representable using a continuum approach. A scenario of interest is, for instance, the simulation of a reconnaissance mission for a high mobility lightweight robot where objects such as a boulder or a ditch that could otherwise be considered small for a truck or tank, become major obstacles that can impede the mobility of the light autonomous vehicle and negatively impact the success of its mission. Analyzing and gauging the mobility and performance of these light vehicles is accomplished through a modeling and simulation capability called Chrono::Engine. Chrono::Engine relies on parallel execution on Graphics Processing Unit (GPU) cards.

  11. Trajectory tracking control for underactuated unmanned surface vehicles with dynamic uncertainties

    Institute of Scientific and Technical Information of China (English)

    廖煜雷; 张铭钧; 万磊; 李晔

    2016-01-01

    The trajectory tracking control problem for underactuated unmanned surface vehicles (USV) was addressed, and the control system took account of the uncertain influences induced by model perturbation, external disturbance, etc. By introducing the reference, trajectory was generated by a virtual USV, and the error equation of trajectory tracking for USV was obtained, which transformed the tracking problem of underactuated USV into the stabilization problem of the trajectory tracking error equation. A backstepping adaptive sliding mode controller was proposed based on backstepping technology and method of dynamic slide model control. By means of theoretical analysis, it is proved that the proposed controller ensures that the solutions of closed loop system have the ultimate boundedness property. Simulation results are presented to illustrate the effectiveness of the proposed controller.

  12. Motion Predicting of Autonomous Tracked Vehicles with Online Slip Model Identification

    Directory of Open Access Journals (Sweden)

    Hao Lu

    2016-01-01

    Full Text Available Precise understanding of the mobility is essential for high performance autonomous tracked vehicles in challenging circumstances, though the complex track/terrain interaction is difficult to model. A slip model based on the instantaneous centers of rotation (ICRs of treads is presented and identified to predict the motion of the vehicle in a short term. Unlike many research studies estimating current ICRs locations using velocity measurements for feedback controllers, we focus on predicting the forward trajectories by estimating ICRs locations using position measurements. ICRs locations are parameterized over both tracks rolling speeds and the kinematic parameters are estimated in real time using an extended Kalman filter (EKF without requiring prior knowledge of terrain parameters. Simulation results verify that the proposed algorithm performs better than the traditional method when the pose measuring frequencies are low. Experiments are conducted on a tracked vehicle with a weight of 13.6 tons. Results demonstrate that the predicted position and heading errors are reduced by about 75% and the reduction of pose errors is over 24% in the absence of the real-time kinematic global positioning system (RTK GPS.

  13. Lane changing trajectory planning and tracking control for intelligent vehicle on curved road.

    Science.gov (United States)

    Wang, Lukun; Zhao, Xiaoying; Su, Hao; Tang, Gongyou

    2016-01-01

    This paper explores lane changing trajectory planning and tracking control for intelligent vehicle on curved road. A novel arcs trajectory is planned for the desired lane changing trajectory. A kinematic controller and a dynamics controller are designed to implement the trajectory tracking control. Firstly, the kinematic model and dynamics model of intelligent vehicle with non-holonomic constraint are established. Secondly, two constraints of lane changing on curved road in practice (LCCP) are proposed. Thirdly, two arcs with same curvature are constructed for the desired lane changing trajectory. According to the geometrical characteristics of arcs trajectory, equations of desired state can be calculated. Finally, the backstepping method is employed to design a kinematic trajectory tracking controller. Then the sliding-mode dynamics controller is designed to ensure that the motion of the intelligent vehicle can follow the desired velocity generated by kinematic controller. The stability of control system is proved by Lyapunov theory. Computer simulation demonstrates that the desired arcs trajectory and state curves with B-spline optimization can meet the requirements of LCCP constraints and the proposed control schemes can make tracking errors to converge uniformly.

  14. Road Target Search and Tracking with Gimballed Vision Sensor on an Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Fredrik Gustafsson

    2012-07-01

    Full Text Available This article considers a sensor management problem where a number of road bounded vehicles are monitored by an unmanned aerial vehicle (UAV with a gimballed vision sensor. The problem is to keep track of all discovered targets and simultaneously search for new targets by controlling the pointing direction of the vision sensor and the motion of the UAV. A planner based on a state-machine is proposed with three different modes; target tracking, known target search, and new target search. A high-level decision maker chooses among these sub-tasks to obtain an overall situational awareness. A utility measure for evaluating the combined search and target tracking performance is also proposed. By using this measure it is possible to evaluate and compare the rewards of updating known targets versus searching for new targets in the same framework. The targets are assumed to be road bounded and the road network information is used both to improve the tracking and sensor management performance. The tracking and search are based on flexible target density representations provided by particle mixtures and deterministic grids.

  15. Distributed output-feedback formation tracking control for unmanned aerial vehicles

    Science.gov (United States)

    He, Lei; Sun, Xiuxia; Lin, Yan

    2016-12-01

    This paper considers the output-feedback formation problem of tracking a desired trajectory for a group of networked unmanned aerial vehicles (UAVs). By introducing a state observer, the controller for the non-holonomic UAV model can be designed without linear and angular velocities measurements. The formation robustness can be improved by applying the virtual structure and synchronising the path parameters. It is proved that, with the proposed control strategy, all the closed-loop signals are bounded and the formation tracking errors asymptotically converge to zero. Simulation results are given to illustrate the effectiveness of the proposed control strategy.

  16. Supervisory controlled operations of UAVs for tracking and surveillance of vehicle targets (SCOUTS)

    Science.gov (United States)

    Fischer, Amber; Denny, Nathan

    2008-04-01

    In this paper, we present SCOUTS, an autonomous system for the allocation of multiple small UAVs equipped with video sensors specifically geared to tracking and reacquisition of vehicle targets in urban environments. To demonstrate SCOUTS performance, we test our system in a simulation incorporating the key challenges encountered by real-time UAV tracking scenarios, including unreliable reports from poor image quality, disruption latency in communication, and temporary gaps in persistent surveillance requiring target re-acquisition strategies. The results provided in this paper establish SCOUTS as a robust approach to this challenging problem.

  17. Multi-Perspective Vehicle Detection and Tracking: Challenges, Dataset, and Metrics

    DEFF Research Database (Denmark)

    Dueholm, Jacob Velling; Kristoffersen, Miklas Strøm; Satzoda, Ravi K.;

    2016-01-01

    this dataset is introduced along with its challenges and evaluation metrics. A vision-based multi-perspective dataset is presented, containing a full panoramic view from a moving platform driving on U.S. highways capturing 2704x1440 resolution images at 12 frames per second. The dataset serves multiple...... purposes to be used as traditional detection and tracking, together with tracking of vehicles across perspectives. Each of the four perspectives have been annotated, resulting in more than 4000 bounding boxes in order to evaluate and compare novel methods....

  18. Resource Saving Approach of Visual Tracking Fiducial Marker Recognition for Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Arunas Andziulis

    2015-01-01

    Full Text Available Unmanned aerial vehicle (UAV tracking fiducial marker is a challenging problem, because of camera system vibration, which causes visible frame-to-frame jitter in the airborne videos and unclear marker vision. Multirotors have very limited weight carrying, controller, and battery power resources. While obtaining and processing motion blurred images, which have no useful information, requires much more image processing subsystem resources. The paper presents blurry image frame elimination based approach of UAV resource saving fiducial marker visual tracking. The proposed approach integrates accelerometer and visual data processing algorithms to predict image blur and skip blurred frames. Experiments have been performed to verify the validity of the proposed approach.

  19. On the possibility of replacing high manganese cast steel military vehicle track pads with ADI

    Directory of Open Access Journals (Sweden)

    M. Kaczorowski

    2010-01-01

    Full Text Available The theoretical considerations of possibility replacing of high manganese cast steel used for military vehicle track pads with ADI are presented. Except these considerations, comparative investigations including tensile strength tests hardness measurements and impact resistance were included. Moreover, the structure investigation was carried out using either conventional light metallography and scanning (SEM. The last one was applied for fractography investigations, the aim of which was to discover the mode of fracture. The discussion of experimental results leads to conclusion that ADI, known as high friction resistant, looks to be concurrent material with respect to high manganese cast steel used now for tang track pads.

  20. 14 CFR 141.91 - Satellite bases.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Satellite bases. 141.91 Section 141.91... OTHER CERTIFICATED AGENCIES PILOT SCHOOLS Operating Rules § 141.91 Satellite bases. The holder of a... assistant chief instructor is designated for each satellite base, and that assistant chief instructor...

  1. A Study on the Dynamic Analysis of A Tracked Vehicle for Ocean Mining on the Deep Seabed

    Institute of Scientific and Technical Information of China (English)

    Hyung-suk HAN

    2003-01-01

    A study is presented on the dynamic analysis of a tracked vehicle for mining on the deep seabed of very soft soil. Equations for the interaction between the track and extremely soft seabed are employed to develop a track/soil interaction module called TVAS. The vehicle is modeled as a multibody dynamic system by the use of a multibody dynamic analysis program. The module developed is cooperated with the multibody dynamic analysis program with a user-defined subroutine. The dynamic behavior and the conceptual design of the mining vehicle on the deep seabed are investigated.

  2. Tracking performance and global stability guaranteed neural control of uncertain hypersonic flight vehicle

    Directory of Open Access Journals (Sweden)

    Tao Teng

    2016-02-01

    Full Text Available In this article, a global adaptive neural dynamic surface control with predefined tracking performance is developed for a class of hypersonic flight vehicles, whose accurate dynamics is hard to obtain. The control scheme developed in this paper overcomes the limitations of neural approximation region by employing a switching mechanism which incorporates an additional robust controller outside the neural approximation region to pull the transient state variables back when they overstep the neural approximation region, such that globally uniformly ultimately bounded stability can be guaranteed. Especially, the developed global adaptive neural control also improves the tracking performance by introducing an error transformation mechanism, such that both transient and steady-state performance can be shaped according to the predefined bounds. Simulation studies on the hypersonic flight vehicle validate that the designed controller has good velocity modulation and velocity stability performance.

  3. Structural Analysis and Improved Design of the Gearbox Casing of a Certain Type of Tracked Vehicle

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xue-sheng; JIA Xiao-ping; CHEN Ya-ning; YU Kui-long

    2011-01-01

    Loads on a gearbox casing of a certain type of tracked vehicle were calculated according to the engine's full load characteristic curve and the worst load condition where the gearbox operated while the tracked vehicle was running, and then stiffness and strength of the casing were analyzed by means of Patran/Nastran software. After a- nalysis, it was found that the casing satisfied the Mises ' yield condition; however, the stress distribution was hetero- geneous, and stresses near the bearing saddle bores of the casing were higher while those in other regions were much less than the allowable stress. For this reason, thicknesses of the casing wall on bearing assembling holes needed in- creasing, while those in other places can decrease. After much structural improving and re-analysis, the optimal casing design was found, and its weight decreased by 5% ; the casing still satisfied the Mises yield criterion and the stress distribution was more homogeneous.

  4. MODELLING AND TORQUE TRACKING CONTROL OF PERMANENT MAGNET SYNCHRONOUS MOTOR FOR HYBRID ELECTRIC VEHICLES

    Directory of Open Access Journals (Sweden)

    Mohd Sabirin Rahmat

    2013-06-01

    Full Text Available This paper presents a detailed derivation of a permanent magnet synchronous motor, which may be used as the electric power train for the simulation of a hybrid electric vehicle. A torque tracking control of the permanent magnet synchronous motor is developed by using an adaptive proportional-integral-derivative controller. Several tests such as step function, saw tooth function, sine wave function and square wave function were used in order to examine the performance of the proposed control structure. The effectiveness of the proposed controller was verified and compared with the same system under a PID controller and the desired control. The result of the observations shows that the proposed control structure proves to be effective in tracking the desired torque with a good response. The findings of this study will be considered in the design, optimisation and experimentation of series hybrid electric vehicle.

  5. Path Planning and Tracking for Vehicle Parallel Parking Based on Preview BP Neural Network PID Controller

    Institute of Scientific and Technical Information of China (English)

    季学武; 王健; 赵又群; 刘亚辉; 臧利国; 李波

    2015-01-01

    In order to diminish the impacts of external disturbance such as parking speed fluctuation and model un-certainty existing in steering kinematics, this paper presents a parallel path tracking method for vehicle based on pre-view back propagation (BP) neural network PID controller. The forward BP neural network can adjust the parameters of PID controller in real time. The preview time is optimized by considering path curvature, change in curvature and road boundaries. A fuzzy controller considering barriers and different road conditions is built to select the starting po-sition. In addition, a kind of path planning technology satisfying the requirement of obstacle avoidance is introduced. In order to solve the problem of discontinuous curvature, cubic B spline curve is used for curve fitting. The simulation results and real vehicle tests validate the effectiveness of the proposed path planning and tracking methods.

  6. Neural Network-Based Adaptive Backstepping Control for Hypersonic Flight Vehicles with Prescribed Tracking Performance

    OpenAIRE

    Zhu Guoqiang; Liu Jinkun

    2015-01-01

    An adaptive neural control scheme is proposed for a class of generic hypersonic flight vehicles. The main advantages of the proposed scheme include the following: (1) a new constraint variable is defined to generate the virtual control that forces the tracking error to fall within prescribed boundaries; (2) RBF NNs are employed to compensate for complex and uncertain terms to solve the problem of controller complexity; (3) only one parameter needs to be updated online at each design step, whi...

  7. Simulation on Dual-stream Transmission System of Unmanned Tracked Armored Vehicle Using ADAMS

    Directory of Open Access Journals (Sweden)

    Sun Wei

    2015-01-01

    Full Text Available For the dual-stream transmission system of unmanned tracked armored vehicle, simulation analysis is carried out. Using SolidWorks to establish three-dimensional model of its chassis, the result of the simulation is processed in AdAMS/Solver. The simulation results are showed in lines. Comparative analysis for each simulation lines is conducted, and it verifies the feasibility of the dual-stream transmission system.

  8. Research on the Effects of Hydropneumatic Parameters on Tracked Vehicle Ride Safety Based on Cosimulation

    Directory of Open Access Journals (Sweden)

    Shousong Han

    2017-01-01

    Full Text Available Ride safety of a tracked vehicle is the key focus of this research. The factors that affect the ride safety of a vehicle are analyzed and evaluation parameters with their criteria are proposed. A multibody cosimulation approach is used to investigate the effects of hydropneumatic parameters on the ride safety and aid with design optimization and tuning of the suspension system. Based on the cosimulation environment, the vehicle multibody dynamics (MBD model and the road model are developed using RecurDyn, which is linked to the hydropneumatic suspension model developed in Lab AMESim. Test verification of a single suspension unit is accomplished and the suspension parameters are implemented within the hydropneumatic model. Virtual tests on a G class road at different speeds are conducted. Effects of the accumulator charge pressure, damping diameter, and the track tensioning pressure on the ride safety are analyzed and quantified. This research shows that low accumulator charge pressure, improper damping diameter, and insufficient track tensioning pressure will deteriorate the ride safety. The results provide useful references for the optimal design and control of the parameters of a hydropneumatic suspension.

  9. ON-BOARD MONITORING OF TECHNICAL STATE FOR POWER UNITS OF WHEELED AND TRACKED VEHICLES

    Directory of Open Access Journals (Sweden)

    Yu. D. Karpievich

    2016-01-01

    Full Text Available The paper considers new methodologies pertaining to on-board diagnosis of wear-out rate for friction linings of a clutch driven disk and friction discs of a hydraulic press clutch of transmission gear boxes which are based on physical process that uses friction work as an integrated indicator. A new methodology in determination of life-span rate for engine oil has been developed in the paper. The paper presents block schematic diagrams for on-board monitoring of technical state for power units of wheeled and tracked vehicles. Usage of friction work as an integrated indicator for determination of wear-out rate for friction linings of clutch driven disk and friction discs of a haydraulic press clutch makes it possible timely at any operational period of wheeled and tracked vehicles to determine their residual operation life and forecast their replacement.While taking volume of the used fuel for determination of engine oil life-span rate it permits quickly and effectively at any operational period of wheeled and tracked vehicles to determine residual useful life of the engine oil and also forecast its replacement.

  10. Longitudinal Acceleration Tracking Control of Low Speed Heavy-Duty Vehicles

    Institute of Scientific and Technical Information of China (English)

    WANG Yuejian; BIN Yang; LI Keqiang

    2008-01-01

    This paper presents a model matching control (MMC) method based on the sliding mode control(SMC) method for longitudinal acceleration tracking control in a vehicular stop-and-go cruise control system.The nonlinearity of the vehicle acceleration response at low speeds was analyzed to develop a transfer function model of the vehicle longitudinal dynamics using the least-mean-square system identification technique.This transfer function was then used to design the MMC controller,including an SMC feedback compensator.The system combines the advantages of the two control methods with robust control and rapid response.Simulations show that the controller enhances the rapid trackability to the vehicle acceleration and improves the system's robustness at low speeds compared with conventional PID MMC controllers.

  11. Tracking Controller Design for Diving Behavior of an Unmanned Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Yi-Hsiang Tseng

    2013-01-01

    Full Text Available The study has investigated the almost disturbance decoupling problem of nonlinear uncertain control systems via the fuzzy feedback linearization approach. The significant dedication of this paper is to organize a control algorithm such that the closed-loop system is active for given initial condition and bounded tracking trajectory with the input-to-state stability and almost disturbance decoupling performance. This study presents a feedback linearization controller for diving control of an unmanned underwater vehicle. Unmanned underwater vehicle proposes difficult control subject due to its nonlinear dynamics, uncertain models, and the existence of disturbances that are difficult to measure. In general, while investigating the diving dynamics of an unmanned underwater vehicle, the pitch angle is always assumed to be small. This assumption is a strong restricting constraint in many interesting practical applications and will be relaxed in this study.

  12. Observer-Based Adaptive Neural Network Trajectory Tracking Control for Remotely Operated Vehicle.

    Science.gov (United States)

    Chu, Zhenzhong; Zhu, Daqi; Yang, Simon X

    2017-07-01

    This paper focuses on the adaptive trajectory tracking control for a remotely operated vehicle (ROV) with an unknown dynamic model and the unmeasured states. Unlike most previous trajectory tracking control approaches, in this paper, the velocity states and the angular velocity states in the body-fixed frame are unmeasured, and the thrust model is inaccurate. Obviously, it is more in line with the actual ROV systems. Since the dynamic model is unknown, a new local recurrent neural network (local RNN) structure with fast learning speed is proposed for online identification. To estimate the unmeasured states, an adaptive terminal sliding-mode state observer based on the local RNN is proposed, so that the finite-time convergence of the trajectory tracking error can be guaranteed. Considering the problem of inaccurate thrust model, an adaptive scale factor is introduced into thrust model, and the thruster control signal is considered as the input of the trajectory tracking system directly. Based on the local RNN output, the adaptive scale factor, and the state estimation values, an adaptive trajectory tracking control law is constructed. The stability of the trajectory tracking control system is analyzed by the Lyapunov theorem. The effectiveness of the proposed control scheme is illustrated by simulations.

  13. A Cost-Effective Tracking Algorithm for Hypersonic Glide Vehicle Maneuver Based on Modified Aerodynamic Model

    Directory of Open Access Journals (Sweden)

    Yu Fan

    2016-10-01

    Full Text Available In order to defend the hypersonic glide vehicle (HGV, a cost-effective single-model tracking algorithm using Cubature Kalman filter (CKF is proposed in this paper based on modified aerodynamic model (MAM as process equation and radar measurement model as measurement equation. In the existing aerodynamic model, the two control variables attack angle and bank angle cannot be measured by the existing radar equipment and their control laws cannot be known by defenders. To establish the process equation, the MAM for HGV tracking is proposed by using additive white noise to model the rates of change of the two control variables. For the ease of comparison several multiple model algorithms based on CKF are presented, including interacting multiple model (IMM algorithm, adaptive grid interacting multiple model (AGIMM algorithm and hybrid grid multiple model (HGMM algorithm. The performances of these algorithms are compared and analyzed according to the simulation results. The simulation results indicate that the proposed tracking algorithm based on modified aerodynamic model has the best tracking performance with the best accuracy and least computational cost among all tracking algorithms in this paper. The proposed algorithm is cost-effective for HGV tracking.

  14. Road boundary estimation to improve vehicle detection and tracking in UAV video

    Institute of Scientific and Technical Information of China (English)

    张立业; 彭仲仁; 李立; 王华

    2014-01-01

    Video processing is one challenge in collecting vehicle trajectories from unmanned aerial vehicle (UAV) and road boundary estimation is one way to improve the video processing algorithms. However, current methods do not work well for low volume road, which is not well-marked and with noises such as vehicle tracks. A fusion-based method termed Dempster-Shafer-based road detection (DSRD) is proposed to address this issue. This method detects road boundary by combining multiple information sources using Dempster-Shafer theory (DST). In order to test the performance of the proposed method, two field experiments were conducted, one of which was on a highway partially covered by snow and another was on a dense traffic highway. The results show that DSRD is robust and accurate, whose detection rates are 100%and 99.8%compared with manual detection results. Then, DSRD is adopted to improve UAV video processing algorithm, and the vehicle detection and tracking rate are improved by 2.7%and 5.5%, respectively. Also, the computation time has decreased by 5%and 8.3%for two experiments, respectively.

  15. Robust tracking control design for a flexible air-breathing hypersonic vehicle

    Institute of Scientific and Technical Information of China (English)

    张垚; 鲜斌; 刁琛; 赵勃; 郭建川

    2014-01-01

    A nonlinear robust controller was presented to improve the tracking control performance of a flexible air-breathing hypersonic vehicle (AHV) which is subjected to system parametric uncertainties and unknown additive time-varying disturbances. The longitudinal dynamic model for the flexible AHV was used for the control development. High-gain observers were designed to compensate for the system uncertainties and additive disturbances. Small gain theorem and Lyapunov based stability analysis were utilized to prove the stability of the closed loop system. Locally uniformly ultimately bounded tracking of the vehicle’s velocity, altitude and attack angle were achieved under aeroelastic effects, system parametric uncertainties and unknown additive disturbances. Matlab/Simulink simulation results were provided to validate the robustness of the proposed control design. The simulation results demonstrate that the tracking errors stay in a small region around zero.

  16. Improved Line Tracking System for Autonomous Navigation of High-Speed Vehicle

    Directory of Open Access Journals (Sweden)

    Yahya Zare Khafri

    2012-07-01

    Full Text Available Line tracking navigation is one of the most widely techniques used in the robot navigation. In this paper, a customized line tracking system is proposed for autonomous navigation of high speed vehicles. In the presented system, auxiliary information -in addition to the road path- is added to the tracking lines such as locations of turn and intersections in the real roads. Moreover, the geometric position of line sensors is re-designed enables the high rate sensing with higher reliability. Finally, a light-weight navigation algorithm is proposed allow the high-speed movement using a reasonable processing power. This system is implemented on a MIPS-based embedded processor and experimental results with this embedded system show more than 98% accuracy at 200km/h with a 1GHz processor is viable.

  17. Pedestrian Detection and Tracking from Low-Resolution Unmanned Aerial Vehicle Thermal Imagery.

    Science.gov (United States)

    Ma, Yalong; Wu, Xinkai; Yu, Guizhen; Xu, Yongzheng; Wang, Yunpeng

    2016-03-26

    Driven by the prominent thermal signature of humans and following the growing availability of unmanned aerial vehicles (UAVs), more and more research efforts have been focusing on the detection and tracking of pedestrians using thermal infrared images recorded from UAVs. However, pedestrian detection and tracking from the thermal images obtained from UAVs pose many challenges due to the low-resolution of imagery, platform motion, image instability and the relatively small size of the objects. This research tackles these challenges by proposing a pedestrian detection and tracking system. A two-stage blob-based approach is first developed for pedestrian detection. This approach first extracts pedestrian blobs using the regional gradient feature and geometric constraints filtering and then classifies the detected blobs by using a linear Support Vector Machine (SVM) with a hybrid descriptor, which sophisticatedly combines Histogram of Oriented Gradient (HOG) and Discrete Cosine Transform (DCT) features in order to achieve accurate detection. This research further proposes an approach for pedestrian tracking. This approach employs the feature tracker with the update of detected pedestrian location to track pedestrian objects from the registered videos and extracts the motion trajectory data. The proposed detection and tracking approaches have been evaluated by multiple different datasets, and the results illustrate the effectiveness of the proposed methods. This research is expected to significantly benefit many transportation applications, such as the multimodal traffic performance measure, pedestrian behavior study and pedestrian-vehicle crash analysis. Future work will focus on using fused thermal and visual images to further improve the detection efficiency and effectiveness.

  18. Pedestrian Detection and Tracking from Low-Resolution Unmanned Aerial Vehicle Thermal Imagery

    Science.gov (United States)

    Ma, Yalong; Wu, Xinkai; Yu, Guizhen; Xu, Yongzheng; Wang, Yunpeng

    2016-01-01

    Driven by the prominent thermal signature of humans and following the growing availability of unmanned aerial vehicles (UAVs), more and more research efforts have been focusing on the detection and tracking of pedestrians using thermal infrared images recorded from UAVs. However, pedestrian detection and tracking from the thermal images obtained from UAVs pose many challenges due to the low-resolution of imagery, platform motion, image instability and the relatively small size of the objects. This research tackles these challenges by proposing a pedestrian detection and tracking system. A two-stage blob-based approach is first developed for pedestrian detection. This approach first extracts pedestrian blobs using the regional gradient feature and geometric constraints filtering and then classifies the detected blobs by using a linear Support Vector Machine (SVM) with a hybrid descriptor, which sophisticatedly combines Histogram of Oriented Gradient (HOG) and Discrete Cosine Transform (DCT) features in order to achieve accurate detection. This research further proposes an approach for pedestrian tracking. This approach employs the feature tracker with the update of detected pedestrian location to track pedestrian objects from the registered videos and extracts the motion trajectory data. The proposed detection and tracking approaches have been evaluated by multiple different datasets, and the results illustrate the effectiveness of the proposed methods. This research is expected to significantly benefit many transportation applications, such as the multimodal traffic performance measure, pedestrian behavior study and pedestrian-vehicle crash analysis. Future work will focus on using fused thermal and visual images to further improve the detection efficiency and effectiveness. PMID:27023564

  19. Pedestrian Detection and Tracking from Low-Resolution Unmanned Aerial Vehicle Thermal Imagery

    Directory of Open Access Journals (Sweden)

    Yalong Ma

    2016-03-01

    Full Text Available Driven by the prominent thermal signature of humans and following the growing availability of unmanned aerial vehicles (UAVs, more and more research efforts have been focusing on the detection and tracking of pedestrians using thermal infrared images recorded from UAVs. However, pedestrian detection and tracking from the thermal images obtained from UAVs pose many challenges due to the low-resolution of imagery, platform motion, image instability and the relatively small size of the objects. This research tackles these challenges by proposing a pedestrian detection and tracking system. A two-stage blob-based approach is first developed for pedestrian detection. This approach first extracts pedestrian blobs using the regional gradient feature and geometric constraints filtering and then classifies the detected blobs by using a linear Support Vector Machine (SVM with a hybrid descriptor, which sophisticatedly combines Histogram of Oriented Gradient (HOG and Discrete Cosine Transform (DCT features in order to achieve accurate detection. This research further proposes an approach for pedestrian tracking. This approach employs the feature tracker with the update of detected pedestrian location to track pedestrian objects from the registered videos and extracts the motion trajectory data. The proposed detection and tracking approaches have been evaluated by multiple different datasets, and the results illustrate the effectiveness of the proposed methods. This research is expected to significantly benefit many transportation applications, such as the multimodal traffic performance measure, pedestrian behavior study and pedestrian-vehicle crash analysis. Future work will focus on using fused thermal and visual images to further improve the detection efficiency and effectiveness.

  20. Modelling, validation and analysis of a three-dimensional railway vehicle-track system model with linear and nonlinear track properties in the presence of wheel flats

    Science.gov (United States)

    Uzzal, R. U. A.; Ahmed, A. K. W.; Bhat, R. B.

    2013-11-01

    This paper presents dynamic contact loads at wheel-rail contact point in a three-dimensional railway vehicle-track model as well as dynamic response at vehicle-track component levels in the presence of wheel flats. The 17-degrees of freedom lumped mass vehicle is modelled as a full car body, two bogies and four wheelsets, whereas the railway track is modelled as two parallel Timoshenko beams periodically supported by lumped masses representing the sleepers. The rail beam is also supported by nonlinear spring and damper elements representing the railpad and ballast. In order to ensure the interactions between the railpads, a shear parameter beneath the rail beams has also been considered into the model. The wheel-rail contact is modelled using nonlinear Hertzian contact theory. In order to solve the coupled partial and ordinary differential equations of the vehicle-track system, modal analysis method is employed. Idealised Haversine wheel flats with the rounded corner are included in the wheel-rail contact model. The developed model is validated with the existing measured and analytical data available in the literature. The nonlinear model is then employed to investigate the wheel-rail impact forces that arise in the wheel-rail interface due to the presence of wheel flats. The validated model is further employed to investigate the dynamic responses of vehicle and track components in terms of displacement, velocity, and acceleration in the presence of single wheel flat.

  1. A Space Based Internet Protocol System for Launch Vehicle Tracking and Control

    Science.gov (United States)

    Bull, Barton; Grant, Charles; Morgan, Dwayne; Streich, Ron; Bauer, Frank (Technical Monitor)

    2001-01-01

    Personnel from the Goddard Space Flight Center Wallops Flight Facility (GSFC/WFF) in Virginia are responsible for the overall management of the NASA Sounding Rocket and Scientific Balloon Programs. Payloads are generally in support of NASA's Space Science Enterprise's missions and return a variety of scientific data as well as providing a reasonably economical means of conducting engineering tests for instruments and devices used on satellites and other spacecraft. Sounding rockets used by NASA can carry payloads of various weights to altitudes from 50 km to more than 1,300 km. Scientific balloons can carry a payload weighing as much as 3,630 Kg to an altitude of 42 km. Launch activities for both are conducted not only from established ranges, but also from remote locations worldwide requiring mobile tracking and command equipment to be transported and set up at considerable expense. The advent of low earth orbit (LEO) commercial communications satellites provides an opportunity to dramatically reduce tracking and control costs of these launch vehicles and Unpiloted Aerial Vehicles (UAVs) by reducing or eliminating this ground infrastructure. Additionally, since data transmission is by packetized Internet Protocol (IP), data can be received and commands initiated from practically any location. A low cost Commercial Off The Shelf (COTS) system is currently under development for sounding rockets that also has application to UAVs and scientific balloons. Due to relatively low data rate (9600 baud) currently available, the system will first be used to provide GPS data for tracking and vehicle recovery. Range safety requirements for launch vehicles usually stipulate at least two independent tracking sources. Most sounding rockets flown by NASA now carry GP receivers that output position data via the payload telemetry system to the ground station. The Flight Modem can be configured as a completely separate link thereby eliminating the requirement for tracking radar. The

  2. Modeling and Performance Prediction of Induction Motor Drive System for Electric Drive Tracked Vehicles

    Institute of Scientific and Technical Information of China (English)

    CHEN Shu-yong; CHEN Quan-shi; SUN Feng-chun

    2007-01-01

    The principle of rotor flux-orientation vector control on 100/150 kW three-phase AC induction motor for electric drive tracked vehicles is analyzed, and the mathematic model is deduced. The drive system of induction motor is modeled and simulated by Matlab/Simulink. The characteristics of motor and drive system are analyzed and evaluated by practical bench test. The simulation and bench test results show that the model is valid, and the driving control system has constant torque under rated speed, constant torque above rated speed, widely variable speed range and better dynamic characteristics. In order to evaluate the practical applications of high power induction motor driving system in electric drive tracked vehicles, a collaborative simulation based on interface technology of Matlab/Simulink and multi-body dynamic analysis software known as RecurDyn is done, the vehicle performances are predicted in the acceleration time (0-32 km/h) and turning characteristic (v=10 km/h, R=B).

  3. Analysis of Rail Vehicle Suspension Spring with Special Emphasis on Curving, Tracking and Tractive Efforts

    Science.gov (United States)

    Kumbhalkar, M. A.; Bhope, D. V.; Vanalkar, A. V.

    2016-09-01

    The dynamics of the rail vehicle represents a balance between the forces acting between wheel and rail, the inertia forces and the forces exerted by suspension and articulation. Axial loading on helical spring causes vertical deflection at straight track but failures calls to investigate for lateral and longitudinal loading at horizontal and vertical curves respectively. Goods carrying vehicle has the frequent failures of middle axle inner suspension spring calls for investigation. The springs are analyzed for effect of stress concentration due to centripetal force and due to tractive and breaking effort. This paper also discusses shear failure analysis of spring at curvature and at uphill at various speeds for different loading condition analytically and by finite element analysis. Two mass rail vehicle suspension systems have been analyzed for vibration responses analytically using mathematical tool Matlab Simulink and the same will be evaluated using FFT vibration analyzer to find peak resonance in vertical, lateral and longitudinal direction. The results prove that the suspension acquires high repeated load in vertical and lateral direction due to tracking and curving causes maximum stress concentration on middle axle suspension spring as height of this spring is larger than end axle spring in primary suspension system and responsible for failure of middle axle suspension spring due to high stress acquisition.

  4. 360-Degree Visual Detection and Target Tracking on an Autonomous Surface Vehicle

    Science.gov (United States)

    Wolf, Michael T; Assad, Christopher; Kuwata, Yoshiaki; Howard, Andrew; Aghazarian, Hrand; Zhu, David; Lu, Thomas; Trebi-Ollennu, Ashitey; Huntsberger, Terry

    2010-01-01

    This paper describes perception and planning systems of an autonomous sea surface vehicle (ASV) whose goal is to detect and track other vessels at medium to long ranges and execute responses to determine whether the vessel is adversarial. The Jet Propulsion Laboratory (JPL) has developed a tightly integrated system called CARACaS (Control Architecture for Robotic Agent Command and Sensing) that blends the sensing, planning, and behavior autonomy necessary for such missions. Two patrol scenarios are addressed here: one in which the ASV patrols a large harbor region and checks for vessels near a fixed asset on each pass and one in which the ASV circles a fixed asset and intercepts approaching vessels. This paper focuses on the ASV's central perception and situation awareness system, dubbed Surface Autonomous Visual Analysis and Tracking (SAVAnT), which receives images from an omnidirectional camera head, identifies objects of interest in these images, and probabilistically tracks the objects' presence over time, even as they may exist outside of the vehicle's sensor range. The integrated CARACaS/SAVAnT system has been implemented on U.S. Navy experimental ASVs and tested in on-water field demonstrations.

  5. Influence of uneven rail irregularities on the dynamic response of the railway track using a three-dimensional model of the vehicle-track system

    Science.gov (United States)

    Naeimi, Meysam; Zakeri, Jabbar Ali; Esmaeili, Morteza; Shadfar, Morad

    2015-01-01

    A mathematical model of the vehicle-track interaction is developed to investigate the coupled behaviour of vehicle-track system, in the presence of uneven irregularities at left/right rails. The railway vehicle is simplified as a 3D multi-rigid-body model, and the track is treated as the two parallel beams on a layered discrete support system. Besides the car-body, the bogies and the wheel sets, the sleepers are assumed to have roll degree of freedom, in order to simulate the in-plane rotation of the components. The wheel-rail interface is treated using a nonlinear Hertzian contact model, coupling the mathematical equations of the vehicle-track systems. The dynamic interaction of the entire system is numerically studied in time domain, employing Newmark's integration method. The track irregularity spectra of both the left/right rails are taken into account, as the inputs of dynamic excitations. The dynamic responses of the track system induced by such irregularities are obtained, particularly in terms of the vertical (bounce) and roll displacements. The numerical model of the present research is validated using several benchmark models reported in the literature, for both the smooth and unsmooth track conditions. Four sample profiles of the measured rail irregularities are considered as the case studies of excitation sources, examining their influences on the dynamic behaviour of the coupled system. The results of numerical simulations demonstrate that the motion of track system is significantly influenced by the presence of uneven irregularities in left/right rails. Dynamic response of the sleepers in the roll direction becomes more sensitive to the rail irregularities, as the unevenness severity of the parallel profiles (quantitative difference between left and right rail spectra) is increased. The severe geometric deformation of the track in the bounce-pitch-roll directions is mainly related to such profile unevenness (cross-level) in left/right rails.

  6. Simultaneous Multi-vehicle Detection and Tracking Framework with Pavement Constraints Based on Machine Learning and Particle Filter Algorithm

    Institute of Scientific and Technical Information of China (English)

    WANG Ke; HUANG Zhi; ZHONG Zhihua

    2014-01-01

    Due to the large variations of environment with ever-changing background and vehicles with different shapes, colors and appearances, to implement a real-time on-board vehicle recognition system with high adaptability, efficiency and robustness in complicated environments, remains challenging. This paper introduces a simultaneous detection and tracking framework for robust on-board vehicle recognition based on monocular vision technology. The framework utilizes a novel layered machine learning and particle filter to build a multi-vehicle detection and tracking system. In the vehicle detection stage, a layered machine learning method is presented, which combines coarse-search and fine-search to obtain the target using the AdaBoost-based training algorithm. The pavement segmentation method based on characteristic similarity is proposed to estimate the most likely pavement area. Efficiency and accuracy are enhanced by restricting vehicle detection within the downsized area of pavement. In vehicle tracking stage, a multi-objective tracking algorithm based on target state management and particle filter is proposed. The proposed system is evaluated by roadway video captured in a variety of traffics, illumination, and weather conditions. The evaluating results show that, under conditions of proper illumination and clear vehicle appearance, the proposed system achieves 91.2% detection rate and 2.6% false detection rate. Experiments compared to typical algorithms show that, the presented algorithm reduces the false detection rate nearly by half at the cost of decreasing 2.7%–8.6% detection rate. This paper proposes a multi-vehicle detection and tracking system, which is promising for implementation in an on-board vehicle recognition system with high precision, strong robustness and low computational cost.

  7. A Mathematical Model and Simulation Results of the Dynamic System Railway Vehicle Wheel–Track with a Wheel Flat

    Directory of Open Access Journals (Sweden)

    Rasa Žygienė

    2014-12-01

    Full Text Available A mathematical model of the system Railway Vehicle Wheel–Track with a wheel flat of a wheelset has been made. The system Railway Vehicle Wheel–Track has been examined on the vertical plane. The mathematical model of the system Railway Vehicle Wheel–Track has employed linear, nonlinear, elastic and damping discrete elements. Rail dynamics haves been described using the finite element method. The unevenness of the rail and the wheel of the wheelset have been evaluated considering the contact between the rail and the wheel flat of the wheelset. The analysis of dynamic processes taking place in a railway vehicle wheel with the wheel flat moving at speed V = 60 km/h has been accomplished. The results of mathematical modelling of the above introduced dynamic system have been presented along with graphically displayed research findings of the conducted research.

  8. Vehicle tracking and navigation systems in mining operations and pulp mills

    Energy Technology Data Exchange (ETDEWEB)

    Harding, T. [Challenger Surveys and Services Ltd., Calgary, AB (Canada)

    1997-12-31

    A vehicle tracking and navigation system used on the Syncrude Aurora site north of Fort McMurray is described. A custom built computer with built in GPS and radio communication is the heart of the system which is used by the auger driver to navigate along ice roads to the auger holes. When the driver completes a hole, he updates the base computer at the Aurora office by means of a portable keypad. Data from the base computer is sent automatically via cell telephone for a near-real time update every 15 minutes to the main computer at Syncrude`s main site 28 km away. All positional data is logged daily for later playback, analysis and use in future planning and optimization of vehicle use.

  9. Fuzzy Logic Control for Semi-Active Suspension System of Tracked Vehicle

    Institute of Scientific and Technical Information of China (English)

    管继富; 顾亮; 侯朝桢; 王国丽

    2004-01-01

    The model of half a tracked vehicle semi-active suspension is established. The fuzzy logic controller of the semi-active suspension system is constructed. The acceleration of driver's seat and its time derivative are used as the inputs of the fuzzy logic controller, and the fuzzy logic controller output determines the semi-active suspension controllable damping force. The fuzzy logic controller is to minimize the mean square root of acceleration of the driver's seat. The control forces of controllable dampers behind the first road wheel are obtained by time delay, and the delay times are determined by the vehicle speed and axles distances. The simulation results show that this control method can decrease the acceleration of driver's seat and the suspension travel of the first road wheel, the ride quality is improved obviously.

  10. Fuzzy Control of Semi-Active Suspension Based on 7-DOF Tracked Vehicle

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ming-ze; ZHANG Yong-fa

    2008-01-01

    On the basis of analyzing the system constitution of tracked vehicle semi-active suspension, which consists of electrorheological (ER) damper and shape memory alloy (SMA) spring, a seven degree of freedom (7-DOF) dynamic model is established. The change of the elasticity of SMA spring and the characteristics of the ER shock absorber are studied. In addition, the study about fuzzy control logic is also carried out. Simulation of a C grade road under random excitations and definite disturbances is performed. Simulation result shows the fuzzy control strategy, which is used in the control of semi-active suspension system with ER damper and SMA springs, is effective, stable and reliable.

  11. Discrete Neural Altitude Control for Hypersonic Vehicle Via Flight Path Angle Tracking

    Directory of Open Access Journals (Sweden)

    Shixing Wang

    2012-09-01

    Full Text Available In this study, the altitude control is analyzed for the longitudinal dynamics of a generic Hypersonic Flight Vehicle (HFV. By transforming altitude command into the tracking of flight path angle with fast dynamics, the system design is focusing on the control of the attitude subsystem. The virtual control is designed with nominal feedback and Neural Network (NN approximation via back-stepping. Under the proposed controller, the Semiglobal Uniform Ultimate Boundedness (SGUUB stability is guaranteed. The slow dynamics are transformed into the parameter estimation problem and the update law is designed. The simulation is presented to show the effectiveness of the proposed control approach.

  12. Study on Modeling and Control Strategy for Electric Drive Motor of Tracked Vehicles

    Institute of Scientific and Technical Information of China (English)

    廖自力; 黄苏融; 马晓军; 庞宾宾

    2012-01-01

    Aimed at the requirements for electric transmission system of a military tracked vehicle, the motor' s design indexes were analysed and calculated. A model based on saturate inductance parameter of interior permanent magnet (IPM) synchronous motor was brought forward by using finite element analysis. And its control strategy based on the largest running capability was studied also. The experiment resuhs for a scale model show that the modelling method improves the model' s accuracy, and the motor' s control strategy is effective.

  13. An optimal consensus tracking control algorithm for autonomous underwater vehicles with disturbances

    CERN Document Server

    Zhang, Jian Yuan Wen-Xia

    2012-01-01

    The optimal disturbance rejection control problem is considered for consensus tracking systems affected by external persistent disturbances and noise. Optimal estimated values of system states are obtained by recursive filtering for the multiple autonomous underwater vehicles modeled to multi-agent systems with Kalman filter. Then the feedforward-feedback optimal control law is deduced by solving the Riccati equations and matrix equations. The existence and uniqueness condition of feedforward-feedback optimal control law is proposed and the optimal control law algorithm is carried out. Lastly, simulations show the result is effectiveness with respect to external persistent disturbances and noise.

  14. Interaction of subway LIM vehicle with ballasted track in polygonal wheel wear development

    Institute of Scientific and Technical Information of China (English)

    Ling Li; Xin-Biao Xiao; Xue-Song Jin

    2011-01-01

    This paper develops a coupled dynamics model for a linear induction motor (LIM) vehicle and a subway track to investigate the influence of polygonal wheels of the vehicle on the dynamic behavior of the system. In the model,the vehicle is modeled as a multi-body system with 35 degrees of freedom. A Timoshenko beam is used to model the rails which are discretely supported by sleepers. The sleepers are modeled as rigid bodies with their vertical, lateral,and rolling motions being considered. In order to simulate the vehicle running along the track, a moving sleeper support model is introduced to simulate the excitation by the discrete sleeper supporters, in which the sleepers are assumed to move backward at a constant speed that is the same as the train speed. The Hertzian contact theory and the ShenHedrick-Elkins' model are utilized to deal with the normal dynamic forces and the tangential forces between wheels and rails, respectively. In order to better characterize the linear metro system (LMS), Euler beam theory based on modal superposition method is used to model LIM and RP. The vertical electric magnetic force and the lateral restoring force between the LIM and RP are also taken into consideration.The former has gap-varying nonlinear characteristics, whilst the latter is considered as a constant restoring force of 1 kN.The numerical analysis considers the effect of the excitation due to polygonal wheels on the dynamic behavior of the system at different wear stages, in which the used data regarding the polygonal wear on the wheel tread are directly measured at the subway site.

  15. Interaction of subway LIM vehicle with ballasted track in polygonal wheel wear development

    Science.gov (United States)

    Li, Ling; Xiao, Xin-Biao; Jin, Xue-Song

    2011-04-01

    This paper develops a coupled dynamics model for a linear induction motor (LIM) vehicle and a subway track to investigate the influence of polygonal wheels of the vehicle on the dynamic behavior of the system. In the model, the vehicle is modeled as a multi-body system with 35 degrees of freedom. A Timoshenko beam is used to model the rails which are discretely supported by sleepers. The sleepers are modeled as rigid bodies with their vertical, lateral, and rolling motions being considered. In order to simulate the vehicle running along the track, a moving sleeper support model is introduced to simulate the excitation by the discrete sleeper supporters, in which the sleepers are assumed to move backward at a constant speed that is the same as the train speed. The Hertzian contact theory and the Shen-Hedrick-Elkins' model are utilized to deal with the normal dynamic forces and the tangential forces between wheels and rails, respectively. In order to better characterize the linear metro system (LMS), Euler beam theory based on modal superposition method is used to model LIM and RP. The vertical electric magnetic force and the lateral restoring force between the LIM and RP are also taken into consideration. The former has gap-varying nonlinear characteristics, whilst the latter is considered as a constant restoring force of 1 kN. The numerical analysis considers the effect of the excitation due to polygonal wheels on the dynamic behavior of the system at different wear stages, in which the used data regarding the polygonal wear on the wheel tread are directly measured at the subway site.

  16. Fuzzy adaptive tracking control within the full envelope for an unmanned aerial vehicle

    Institute of Scientific and Technical Information of China (English)

    Liu Zhi; Wang Yong

    2014-01-01

    Motivated by the autopilot of an unmanned aerial vehicle (UAV) with a wide flight enve-lope span experiencing large parametric variations in the presence of uncertainties, a fuzzy adaptive tracking controller (FATC) is proposed. The controller consists of a fuzzy baseline controller and an adaptive increment, and the main highlight is that the fuzzy baseline controller and adaptation laws are both based on the fuzzy multiple Lyapunov function approach, which helps to reduce the conservatism for the large envelope and guarantees satisfactory tracking performances with strong robustness simultaneously within the whole envelope. The constraint condition of the fuzzy baseline controller is provided in the form of linear matrix inequality (LMI), and it specifies the satisfactory tracking performances in the absence of uncertainties. The adaptive increment ensures the uniformly ultimately bounded (UUB) predication errors to recover satisfactory responses in the presence of uncertainties. Simulation results show that the proposed controller helps to achieve high-accuracy tracking of airspeed and altitude desirable commands with strong robustness to uncertainties throughout the entire flight envelope.

  17. Effective real-time vehicle tracking using discriminative sparse coding on local patches

    Science.gov (United States)

    Chen, XiangJun; Ye, Feiyue; Ruan, Yaduan; Chen, Qimei

    2016-01-01

    A visual tracking framework that provides an object detector and tracker, which focuses on effective and efficient visual tracking in surveillance of real-world intelligent transport system applications, is proposed. The framework casts the tracking task as problems of object detection, feature representation, and classification, which is different from appearance model-matching approaches. Through a feature representation of discriminative sparse coding on local patches called DSCLP, which trains a dictionary on local clustered patches sampled from both positive and negative datasets, the discriminative power and robustness has been improved remarkably, which makes our method more robust to a complex realistic setting with all kinds of degraded image quality. Moreover, by catching objects through one-time background subtraction, along with offline dictionary training, computation time is dramatically reduced, which enables our framework to achieve real-time tracking performance even in a high-definition sequence with heavy traffic. Experiment results show that our work outperforms some state-of-the-art methods in terms of speed, accuracy, and robustness and exhibits increased robustness in a complex real-world scenario with degraded image quality caused by vehicle occlusion, image blur of rain or fog, and change in viewpoint or scale.

  18. Fuzzy adaptive tracking control within the full envelope for an unmanned aerial vehicle

    Directory of Open Access Journals (Sweden)

    Liu Zhi

    2014-10-01

    Full Text Available Motivated by the autopilot of an unmanned aerial vehicle (UAV with a wide flight envelope span experiencing large parametric variations in the presence of uncertainties, a fuzzy adaptive tracking controller (FATC is proposed. The controller consists of a fuzzy baseline controller and an adaptive increment, and the main highlight is that the fuzzy baseline controller and adaptation laws are both based on the fuzzy multiple Lyapunov function approach, which helps to reduce the conservatism for the large envelope and guarantees satisfactory tracking performances with strong robustness simultaneously within the whole envelope. The constraint condition of the fuzzy baseline controller is provided in the form of linear matrix inequality (LMI, and it specifies the satisfactory tracking performances in the absence of uncertainties. The adaptive increment ensures the uniformly ultimately bounded (UUB predication errors to recover satisfactory responses in the presence of uncertainties. Simulation results show that the proposed controller helps to achieve high-accuracy tracking of airspeed and altitude desirable commands with strong robustness to uncertainties throughout the entire flight envelope.

  19. Analysis of the Dynamic Response in the Railway Vehicles to the Track Vertical Irregularities. Part I: The Theoretical Model and the Vehicle Response Functions

    OpenAIRE

    M. Dumitriu

    2015-01-01

    The paper herein focuses on the dynamic response of a two-bogie vehicle to the excitations derived from the track vertical irregularities. The symmetrical and antisymmetrical modes due from the bounce and pitch motions of the axles’ planes in the two bogies are being considered. The analysis of the dynamic response in the vehicle relies on the response functions in three reference points of the carbody, composed by means of these response functions to the symmetrical and antisymme...

  20. Analysis of the dynamic response in the railway vehicles to the track vertical irregularities. Part II: The numerical analysis

    Directory of Open Access Journals (Sweden)

    M. Dumitriu

    2015-11-01

    Full Text Available The paper examines the dynamic response of a two-bogie vehicle to the symmetrical and antisymmetrical excitations, due to bounce and pitch of the axles’ planes, derived from the track vertical irregularities. Part I introduced the theoretical model and the response functions of the vehicle, as well as the theoretical elements required for the analysis of the dynamic response of the vehicle to the track stochastic irregularities. Part II comprises the results of the numerical analysis of the vehicle dynamic response in three reference points of the carbody, based on which a series of properties of the vertical vibrations behaviour of the railway vehicle is pointed out at. The excitation modes that trigger the carbody response in its reference points are identified. Hence, the influence of the geometrical filtering effect of the excitation modes upon the ride quality and ride comfort is established.

  1. Dynamic Response Analysis of an Asymmetric Coupled Vehicle-Track System Generated by Voided Elastic Two-Block Sleeper

    Directory of Open Access Journals (Sweden)

    Zhenxing He

    2016-01-01

    Full Text Available Based on vehicle-track coupled dynamic theory, a three-dimensional asymmetric vehicle-track coupling vibration model is developed to investigate the effect of voided elastic two-block sleepers on vehicle and track system dynamic responses. For the vehicle system, one car body, two frames, and four wheel sets are assumed to be rigid, with 35 degrees of freedom (DOF. For the track system, the rails and the concrete two-block sleepers are the main vibration components. The rails are modelled as Timoshenko beams, and the concrete two-block sleepers are assumed to be rigid mass with vertical and lateral movement. The pads under the rails and the rubber boots under the sleepers provide greater vertical and lateral elasticity for the track. The Hertz nonlinear elastic contact theory is used to calculate the normal wheel/rail force. The wheel/rail tangent creep force is first calculated using Kalker’s linear creep theory and then modified by the Shen-Hedrick-Elkins theory. The results show that the asymmetric voided elastic two-block sleepers have greater effects on the dynamic responses for fasteners and sleepers than on the car body and the wheel/rail forces under measured geometric irregularity and random irregularity. Two or more voided sleepers will greatly affect the vehicle running safety.

  2. Fuzzy distributed cooperative tracking for a swarm of unmanned aerial vehicles with heterogeneous goals

    Science.gov (United States)

    Kladis, Georgios P.; Menon, Prathyush P.; Edwards, Christopher

    2016-12-01

    This article proposes a systematic analysis for a tracking problem which ensures cooperation amongst a swarm of unmanned aerial vehicles (UAVs), modelled as nonlinear systems with linear and angular velocity constraints, in order to achieve different goals. A distributed Takagi-Sugeno (TS) framework design is adopted for the representation of the nonlinear model of the dynamics of the UAVs. The distributed control law which is introduced is composed of both node and network level information. Firstly, feedback gains are synthesised using a parallel distributed compensation (PDC) control law structure, for a collection of isolated UAVs; ignoring communications among the swarm. Then secondly, based on an alternation-like procedure, the resulting feedback gains are used to determine Lyapunov matrices which are utilised at network level to incorporate into the control law, the relative differences in the states of the vehicles, and to induce cooperative behaviour. Eventually stability is guaranteed for the entire swarm. The control synthesis is performed using tools from linear control theory: in particular the design criteria are posed as linear matrix inequalities (LMIs). An example based on a UAV tracking scenario is included to outline the efficacy of the approach.

  3. Tracking error constrained robust adaptive neural prescribed performance control for flexible hypersonic flight vehicle

    Directory of Open Access Journals (Sweden)

    Zhonghua Wu

    2017-02-01

    Full Text Available A robust adaptive neural control scheme based on a back-stepping technique is developed for the longitudinal dynamics of a flexible hypersonic flight vehicle, which is able to ensure the state tracking error being confined in the prescribed bounds, in spite of the existing model uncertainties and actuator constraints. Minimal learning parameter technique–based neural networks are used to estimate the model uncertainties; thus, the amount of online updated parameters is largely lessened, and the prior information of the aerodynamic parameters is dispensable. With the utilization of an assistant compensation system, the problem of actuator constraint is overcome. By combining the prescribed performance function and sliding mode differentiator into the neural back-stepping control design procedure, a composite state tracking error constrained adaptive neural control approach is presented, and a new type of adaptive law is constructed. As compared with other adaptive neural control designs for hypersonic flight vehicle, the proposed composite control scheme exhibits not only low-computation property but also strong robustness. Finally, two comparative simulations are performed to demonstrate the robustness of this neural prescribed performance controller.

  4. Anti-jackknife reverse tracking control of articulated vehicles in the presence of actuator saturation

    Science.gov (United States)

    Yuan, H.; Zhu, H.

    2016-10-01

    It is well known that backward motion control of an articulated vehicle is difficult because it is an open loop unstable system and such motion is also dangerous due to 'jackknifing'. In this paper, an anti-jackknife reverse tracking control strategy for autonomous articulated vehicles is proposed based on the combined longitudinal and lateral control scheme. In the proposed lateral-longitudinal control scheme, the major task is to control the reverse heading of the trailer by automatic steering strategies that observe both the anti-jackknife condition and input limitations. The main contribution of this paper is the development of globally asymptotic anti-jackknife stabilising and tracking controls of heading angles with both state and input constraints considered a priori. The proposed control inherently has an anti-windup mechanism that prevents the hitch angle from going beyond any specified critical value to avoid jackknifing, during which time, the steering angle remains at its limit. Stability of the controller is theoretically proven via the Lyapunov argument. Effectiveness of the proposed approach is demonstrated by CarSim and Simulink joint simulations.

  5. Design and Optimization of the Power Management Strategy of an Electric Drive Tracked Vehicle

    Directory of Open Access Journals (Sweden)

    Qunzhang Tu

    2016-01-01

    Full Text Available This article studies the power management control strategy of electric drive system and, in particular, improves the fuel economy for electric drive tracked vehicles. Combined with theoretical analysis and experimental data, real-time control oriented models of electric drive system are established. Taking into account the workloads of engine and the SOC (state of charge of battery, a fuzzy logic based power management control strategy is proposed. In order to achieve a further improvement in fuel economic, a DEHPSO algorithm (differential evolution based hybrid particle swarm optimization is adopted to optimize the membership functions of fuzzy controller. Finally, to verify the validity of control strategy, a HILS (hardware-in-the-loop simulation platform is built based on dSPACE and related experiments are carried out. The results indicate that the proposed strategy obtained good effects on power management, which achieves high working efficiency and power output capacity. Optimized by DEHPSO algorithm, fuel consumption of the system is decreased by 4.88% and the fuel economy is obviously improved, which will offer an effective way to improve integrated performance of electric drive tracked vehicles.

  6. Dynamic surface tracking controller design for a constrained hypersonic vehicle based on disturbance observer

    Directory of Open Access Journals (Sweden)

    Fang Wang

    2017-05-01

    Full Text Available The tracking control problem of a flexible air-breathing hypersonic vehicle subjects to aerodynamic parameter uncertainty and input constraint is investigated by combining nonlinear disturbance observer and dynamic surface control. To design controller simply, a control-oriented model is firstly derived and divided into two subsystems, velocity subsystem and altitude subsystem based on the engineering backgrounds of flexible air-breathing hypersonic vehicle. In every subsystem, compounded disturbances are included to consider aerodynamic uncertainty and the effect of the flexible modes. Then, disturbance observer is not only used to handle the compounded disturbance but also to handle the input constraint, where the estimation error converges to a random small region through appropriately choosing the observer parameters. To sequel, the disturbance observer–based robust control scheme and the disturbance observer-based dynamic surface control scheme are developed for the velocity subsystem and altitude subsystem, respectively. Besides, novel filters are designed to alleviate the problem of “explosion of terms” induced by backstepping method. On the basis of Lyapunov stability theory, the presented control scheme can assure that tracking error converges to an arbitrarily small neighborhood around zero by rigorous theoretical analysis. At last, simulation result shows the effectiveness of the presented control method.

  7. Hybrid three-dimensional and support vector machine approach for automatic vehicle tracking and classification using a single camera

    Science.gov (United States)

    Kachach, Redouane; Cañas, José María

    2016-05-01

    Using video in traffic monitoring is one of the most active research domains in the computer vision community. TrafficMonitor, a system that employs a hybrid approach for automatic vehicle tracking and classification on highways using a simple stationary calibrated camera, is presented. The proposed system consists of three modules: vehicle detection, vehicle tracking, and vehicle classification. Moving vehicles are detected by an enhanced Gaussian mixture model background estimation algorithm. The design includes a technique to resolve the occlusion problem by using a combination of two-dimensional proximity tracking algorithm and the Kanade-Lucas-Tomasi feature tracking algorithm. The last module classifies the shapes identified into five vehicle categories: motorcycle, car, van, bus, and truck by using three-dimensional templates and an algorithm based on histogram of oriented gradients and the support vector machine classifier. Several experiments have been performed using both real and simulated traffic in order to validate the system. The experiments were conducted on GRAM-RTM dataset and a proper real video dataset which is made publicly available as part of this work.

  8. A study on RFID adoption for vehicle tracking in container terminal

    Directory of Open Access Journals (Sweden)

    S.L. Ting

    2012-06-01

    Full Text Available Purpose: Numerous studies discuss that Radio Frequency Identification (RFID technology can provide better container handling efficiency; however, relative lack of research concerns the tracking and monitoring the movement of vehicle in the container terminal environment. Thus, this study aims at discussing the feasibility of applying RFID for vehicle tracking purpose in a container terminal. Design/methodology/approach: This study makes use of a series of experiments in a container terminal to discuss the factors that affect the use of RFID in the terminal. The possibility and accuracy of using RFID in such challenging environment is also investigated. These propositions are investigated by a case study. Findings: The experimental results indicate that the RFID communication is good at the containers area which occupies nearly all the area in the container terminal. However, in other area such as sea side and free area, the performance is not good and 100% readability only achieved in 5m and 10m in free area and sea side respectively. Originality/value: The container terminal environment, which consists of different transport vehicles for onward transportation, will affect the performance of RFID readability. Poor setup of the RFID reader and tag will lower the feasibility of RFID adoption as well as increase the cost. In order to address the challenges of implementing RFID in the container terminal environment, this paper provides a series of real site testing experiments to study the RFID performance in the container terminal environment. This represents an original contribution of value to future research and practice in the RFID adoptions in container terminal environment.

  9. Satellite-Based Quantum Communications

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Richard J [Los Alamos National Laboratory; Nordholt, Jane E [Los Alamos National Laboratory; McCabe, Kevin P [Los Alamos National Laboratory; Newell, Raymond T [Los Alamos National Laboratory; Peterson, Charles G [Los Alamos National Laboratory

    2010-09-20

    Single-photon quantum communications (QC) offers the attractive feature of 'future proof', forward security rooted in the laws of quantum physics. Ground based quantum key distribution (QKD) experiments in optical fiber have attained transmission ranges in excess of 200km, but for larger distances we proposed a methodology for satellite-based QC. Over the past decade we have devised solutions to the technical challenges to satellite-to-ground QC, and we now have a clear concept for how space-based QC could be performed and potentially utilized within a trusted QKD network architecture. Functioning as a trusted QKD node, a QC satellite ('QC-sat') could deliver secret keys to the key stores of ground-based trusted QKD network nodes, to each of which multiple users are connected by optical fiber or free-space QC. A QC-sat could thereby extend quantum-secured connectivity to geographically disjoint domains, separated by continental or inter-continental distances. In this paper we describe our system concept that makes QC feasible with low-earth orbit (LEO) QC-sats (200-km-2,000-km altitude orbits), and the results of link modeling of expected performance. Using the architecture that we have developed, LEO satellite-to-ground QKD will be feasible with secret bit yields of several hundred 256-bit AES keys per contact. With multiple ground sites separated by {approx} 100km, mitigation of cloudiness over any single ground site would be possible, potentially allowing multiple contact opportunities each day. The essential next step is an experimental QC-sat. A number of LEO-platforms would be suitable, ranging from a dedicated, three-axis stabilized small satellite, to a secondary experiment on an imaging satellite. to the ISS. With one or more QC-sats, low-latency quantum-secured communications could then be provided to ground-based users on a global scale. Air-to-ground QC would also be possible.

  10. Localization and Tracking of Submerged Phytoplankton Bloom Patches by an Autonomous Underwater Vehicle

    Science.gov (United States)

    Godin, M. A.; Ryan, J. P.; Zhang, Y.; Bellingham, J. G.

    2012-12-01

    Observing plankton in their drifting frame of reference permits effective studies of marine ecology from the perspective of microscopic life itself. By minimizing variation caused simply by advection, observations in a plankton-tracking frame of reference focus measurement capabilities on the processes that influence the life history of populations. Further, the patchy nature of plankton populations motivates use of sensor data in real-time to resolve patch boundaries and adapt observing resources accordingly. We have developed capabilities for population-centric plankton observation and sampling by autonomous underwater vehicles (AUVs). Our focus has been on phytoplankton populations, both because of their ecological significance - as the core of the oceanic food web and yet potentially harmful under certain bloom conditions, as well as the accessibility of their signal to simple optical sensing. During the first field deployment of these capabilities in 2010, we tracked a phytoplankton patch containing toxigenic diatoms and found that their toxicity correlated with exposure to resuspended sediments. However, this first deployment was labor intensive as the AUV drove in a pre-programmed pattern centered around a patch-marking drifter; it required a boat deployment of the patch-marking drifter and required full-time operators to periodically estimate of the position of the patch with respect to the drifter and adjust the AUV path accordingly. In subsequent field experiments during 2011 and 2012, the Tethys-class long-range AUVs ran fully autonomous patch tracking algorithms which detected phytoplankton patches and continually updated estimates of each patch center by driving adaptive patterns through the patch. Iterations of the algorithm were generated to overcome the challenges of tracking advecting and evolving patches while minimizing human involvement in vehicle control. Such fully autonomous monitoring will be necessary to perform long-term in

  11. Neural Network-Based Adaptive Backstepping Control for Hypersonic Flight Vehicles with Prescribed Tracking Performance

    Directory of Open Access Journals (Sweden)

    Zhu Guoqiang

    2015-01-01

    Full Text Available An adaptive neural control scheme is proposed for a class of generic hypersonic flight vehicles. The main advantages of the proposed scheme include the following: (1 a new constraint variable is defined to generate the virtual control that forces the tracking error to fall within prescribed boundaries; (2 RBF NNs are employed to compensate for complex and uncertain terms to solve the problem of controller complexity; (3 only one parameter needs to be updated online at each design step, which significantly reduces the computational burden. It is proved that all signals of the closed-loop system are uniformly ultimately bounded. Simulation results are presented to illustrate the effectiveness of the proposed scheme.

  12. Predictive Sliding Mode Control for Attitude Tracking of Hypersonic Vehicles Using Fuzzy Disturbance Observer

    Directory of Open Access Journals (Sweden)

    Xianlei Cheng

    2015-01-01

    Full Text Available We propose a predictive sliding mode control (PSMC scheme for attitude control of hypersonic vehicle (HV with system uncertainties and external disturbances based on an improved fuzzy disturbance observer (IFDO. First, for a class of uncertain affine nonlinear systems with system uncertainties and external disturbances, we propose a predictive sliding mode control based on fuzzy disturbance observer (FDO-PSMC, which is used to estimate the composite disturbances containing system uncertainties and external disturbances. Afterward, to enhance the composite disturbances rejection performance, an improved FDO-PSMC (IFDO-PSMC is proposed by incorporating a hyperbolic tangent function with FDO to compensate for the approximate error of FDO. Finally, considering the actuator dynamics, the proposed IFDO-PSMC is applied to attitude control system design for HV to track the guidance commands with high precision and strong robustness. Simulation results demonstrate the effectiveness and robustness of the proposed attitude control scheme.

  13. A satellite based telemetry link for a UAV application

    Science.gov (United States)

    Bloise, Anthony

    1995-01-01

    The requirements for a satellite based communication facility to service the needs of the Geographical Information System (GIS) data collection community are addressed in this paper. GIS data is supplied in the form of video imagery at sub-television rates in one or more spectral bands / polarizations laced with a position correlated data stream. The limitations and vicissitudes of using a terrestrial based telecommunications link to collect GIS data are illustrated from actual mission scenarios. The expectations from a satellite based communications link by the geophysical data collection community concerning satellite architecture, operating bands, bandwidth, footprint agility, up link and down link hardware configurations on the UAV, the Mobile Control Vehicle and at the Central Command and Data Collection Facility comprise the principle issues discussed in the first section of this paper. The final section of the paper discusses satellite based communication links would have an increased volume and scope of services the GIS data collection community could make available to the GIS user community, and the price the data collection community could afford to pay for access to the communication satellite described in the paper.

  14. DEVELOPMENT OF A SIMULATION TOOL FOR THE DYNAMIC ANALYSIS OF RAILWAY VEHICLE - TRACK INTERACTION

    Directory of Open Access Journals (Sweden)

    Ramy SHALTOUT

    2015-12-01

    Full Text Available The importance of modelling and simulation in the field of railway systems has greatly increased in the last decades. Various commercial simulation packages have been developed and are used to analyse the dynamic performance of railway systems. However, although sometimes the user needs to analyse various non-standard solutions, the possibility to integrate further modifications into the structure of such software is quite limited. Therefore, in some cases, in particular for specific modelling and analysis tasks, a feasible option is to develop flexible and robust simulation tools capable of using different configurations by modifying the models performing the dynamic analysis. The paper presents the mathematical modelling background and the conceptual design of a new of a new computational tool for the dynamic simulation of railway vehicle systems. The formulations employed in the proposed mathematical model are based on the multibody techniques. The developed model uses a combined frame of references that allows the use of independent coordinates without the possibility to have singularity configurations depending on the rotation sequence. The simulation tool is designed in a flexible form that enables the study of different configurations of the railway vehicles, as well as various track combinations.

  15. Optimum municipal solid waste collection using geographical information system (GIS) and vehicle tracking for Pallavapuram municipality.

    Science.gov (United States)

    Kanchanabhan, T E; Abbas Mohaideen, J; Srinivasan, S; Sundaram, V Lenin Kalyana

    2011-03-01

    Waste collection and transportation is the contact point between waste generators and waste management systems. A proposal for an innovative model for the collection and transportation of municipal solid waste (MSW) which is a part of a solid waste management system using a spatial geo database, integrated in a geographical information system (GIS) environment is presented. Pallavapuram is a fast-developing municipality of Chennai city in the southern suburbs about 20 km from Chennai, the state capital of Tamil Nadu in India. The disposal of MSW was previously occurring in an indiscriminate and irrational manner in the municipality. Hence in the present study an attempt was made to develop an engineered design of solid waste collection using GIS with a vehicle tracking system and final disposal by composting with investment costs. The GIS was used to analyse existing maps and data, to digitize the existing ward boundaries and to enter data about the wards and disposal sites. The proposed GIS model for solid waste disposal would give information on the planning of bins, vehicles and the optimal route. In the case of disposal, composting would be a successful strategy to accelerate the decomposition and stabilization of the biodegradable components of waste in MSW.

  16. Modeling and Robust Trajectory Tracking Control for a Novel Six-Rotor Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Chengshun Yang

    2013-01-01

    Full Text Available Modeling and trajectory tracking control of a novel six-rotor unmanned aerial vehicle (UAV is concerned to solve problems such as smaller payload capacity and lack of both hardware redundancy and anticrosswind capability for quad-rotor. The mathematical modeling for the six-rotor UAV is developed on the basis of the Newton-Euler formalism, and a second-order sliding-mode disturbance observer (SOSMDO is proposed to reconstruct the disturbances of the rotational dynamics. In consideration of the under-actuated and strong coupling properties of the six-rotor UAV, a nested double loops trajectory tracking control strategy is adopted. In the outer loop, a position error PID controller is designed, of which the task is to compare the desired trajectory with real position of the six-rotor UAV and export the desired attitude angles to the inner loop. In the inner loop, a rapid-convergent nonlinear differentiator (RCND is proposed to calculate the derivatives of the virtual control signal, instead of using the analytical differentiation, to avoid “differential expansion” in the procedure of the attitude controller design. Finally, the validity and effectiveness of the proposed technique are demonstrated by the simulation results.

  17. Study on turning performance of four-track steering vehicles. Effect of traction force and track speed distribution control; Sodashiki sokisha no senkai seino ni kansuru kenkyu. Kudoryoku haibun to sokudo haibun no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Imamura, M.; Watanabe, K.; Kitano, M. [National Defense Academy, Kanagawa (Japan)

    1997-10-01

    The four-track steering vehicles (4TS) is a new type of off-road vehicle which can replace four wheels with track units to improve the mobility on soft terrains. In this paper, the numerical simulations, under the various types of differential and track velocity control systems, are conducted to predict the turning performance and steer ability of the 4TS vehicles. The results of the numerical analysis demonstrate that the differential systems with realistic combined distribution control systems of the track speed is efficient at a small turning radius. 4 refs., 13 figs.

  18. 75 FR 25927 - Vehicle/Track Interaction Safety Standards; High-Speed and High Cant Deficiency Operations

    Science.gov (United States)

    2010-05-10

    ... From the Federal Register Online via the Government Publishing Office ] Part II Department of Transportation Federal Railroad Administration 49 CFR Parts 213 and 238 Vehicle/Track Interaction Safety Standards; High-Speed and High Cant Deficiency Operations; Proposed Rule #0;#0;Federal Register / Vol....

  19. An adaptive trajectory tracking control of four rotor hover vehicle using extended normalized radial basis function network

    Science.gov (United States)

    ul Amin, Rooh; Aijun, Li; Khan, Muhammad Umer; Shamshirband, Shahaboddin; Kamsin, Amirrudin

    2017-01-01

    In this paper, an adaptive trajectory tracking controller based on extended normalized radial basis function network (ENRBFN) is proposed for 3-degree-of-freedom four rotor hover vehicle subjected to external disturbance i.e. wind turbulence. Mathematical model of four rotor hover system is developed using equations of motions and a new computational intelligence based technique ENRBFN is introduced to approximate the unmodeled dynamics of the hover vehicle. The adaptive controller based on the Lyapunov stability approach is designed to achieve tracking of the desired attitude angles of four rotor hover vehicle in the presence of wind turbulence. The adaptive weight update based on the Levenberg-Marquardt algorithm is used to avoid weight drift in case the system is exposed to external disturbances. The closed-loop system stability is also analyzed using Lyapunov stability theory. Simulations and experimental results are included to validate the effectiveness of the proposed control scheme.

  20. An Method for Vehicle-Flow Detection and Tracking in Real-Time Based on Gaussian Mixture Distribution

    Directory of Open Access Journals (Sweden)

    Ronghui Zhang

    2013-01-01

    Full Text Available Vehicle-flow detection and tracking by digital image are one of the most important technologies in the traffic monitoring system. Gaussian mixture distribution method is used to eliminate the influence of moving vehicle firstly in this text, and then we built the background images for vehicle flow. Combining the advantages of background difference algorithm with inter frame difference operator, the real-time background is segmented integrally and dynamically updated accurately by matching the reconstructed image with current background. In order to ensure the robustness of vehicle detection, three by three window templates are adopted to remove the isolated noise spot in the image of vehicle contour. The template structural element is used to do some graphical morphological filtering. So, the corrosion and expansion sets are obtained. To narrow the target search scope and improve the calculation speed and precision of the algorithm, Kalman filtering model is used to realize the tracking of fast moving vehicles. Experimental results show that the method has good real-time and reliable performance.

  1. Effects of Heavy, Tracked-Vehicle Disturbance on Forest Soil Properties at Fort Benning, Georgia

    Energy Technology Data Exchange (ETDEWEB)

    Garten, C.T.,JR.

    2004-05-20

    The purpose of this report is to describe the effects of heavy, tracked-vehicle disturbance on various measures of soil quality in training compartment K-11 at Fort Benning, Georgia. Predisturbance soil sampling in April and October of 2002 indicated statistically significant differences in soil properties between upland and riparian sites. Soil density was less at riparian sites, but riparian soils had significantly greater C and N concentrations and stocks than upland soils. Most of the C stock in riparian soils was associated with mineral-associated organic matter (i.e., the silt + clay fraction physically separated from whole mineral soil). Topographic differences in soil N availability were highly dependent on the time of sampling. Riparian soils had higher concentrations of extractable inorganic N than upland soils and also exhibited significantly greater soil N availability during the spring sampling. The disturbance experiment was performed in May 2003 by driving a D7 bulldozer through the mixed pine/hardwood forest. Post-disturbance sampling was limited to upland sites because training with heavy, tracked vehicles at Fort Benning is generally confined to upland soils. Soil sampling approximately one month after the experiment indicated that effects of the bulldozer were limited primarily to the forest floor (O-horizon) and the surface (0-10 cm) mineral soil. O-horizon dry mass and C stocks were significantly reduced, relative to undisturbed sites, and there was an indication of reduced mineral soil C stocks in the disturbance zone. Differences in the surface (0-10 cm) mineral soil also indicated a significant increase in soil density as a result of disturbance by the bulldozer. Although there was some tendency for greater soil N availability in disturbed soils, the changes were not significantly different from undisturbed controls. It is expected that repeated soil disturbance over time, which will normally occur in a military training area, would simply

  2. Analysis of the Dynamic Response in the Railway Vehicles to the Track Vertical Irregularities. Part I: The Theoretical Model and the Vehicle Response Functions

    Directory of Open Access Journals (Sweden)

    M. Dumitriu

    2015-11-01

    Full Text Available The paper herein focuses on the dynamic response of a two-bogie vehicle to the excitations derived from the track vertical irregularities. The symmetrical and antisymmetrical modes due from the bounce and pitch motions of the axles’ planes in the two bogies are being considered. The analysis of the dynamic response in the vehicle relies on the response functions in three reference points of the carbody, composed by means of these response functions to the symmetrical and antisymmetrical excitation modes. Similarly, the dynamic response of the vehicle to the track stochastic irregularities is examined and expressed as a power spectral density of the carbody vertical acceleration and the root mean square of the acceleration and the index of the partial comfort to the vertical vibrations is calculated. The paper is structured into two parts. The Part I includes all the theoretical elements required for the analysis of the dynamic response in the vehicle, while Part II introduces the results of the numerical analysis.

  3. Low-elevation tracking technique for X-band unmanned aerial vehicle automatic take-off and landing system

    Science.gov (United States)

    Lin, S.-Y.; Cho, M.-H.; Lin, M.-Y.; Hu, W.-Y.; Sun, J.-S.

    2017-05-01

    In this study, an automatic take-off and landing system (ATOLS) based on radar guidance was developed to provide day/night, all weather, automatic takeoff and landing for unmanned aerial vehicles (UAVs). The ATOLS contains a ground-based tracking radar subsystem and an airborne transponder subsystem. This X-band tracking radar can provide precise position information for UAV-control operations (transponder mode) and fire-control systems (skin mode). It provides 360 degrees of azimuth coverage and therefore can be employed for navigation applications. Its maximum tracking range is about 17 km and accuracy of altitude measurement is about 1 ft with a 50-ft decision height above ground level. To substantiate the proposed ATOLS system, a differential global positioning system (DGPS) was also developed. When a UAV at a low-elevation angle is detected and tracked by a tracking radar, multipath propagation often leads to the degradation of tracking accuracy or even cause the radar to break track. As a result, it becomes a potential risk to flight safety of the ATOLS guidance and control of UAVs. To overcome this technical difficulty, this paper proposes a solution based on optimization of radar parameters to mitigate the interference from multipath signals. The feasibility of proposed method has been experimentally proven through the flight trials of UAVs. Compared to the conventional low-elevation tracking techniques, the proposed one employs the radar signal processing, and does not consume additional hardware and resources.

  4. Performance analysis of IMU-augmented GNSS tracking systems for space launch vehicles

    Science.gov (United States)

    Braun, Benjamin; Markgraf, Markus; Montenbruck, Oliver

    2016-06-01

    European space launch operators consider the potential of GNSS (global navigation satellite system) as a promising novel means of localization for the purpose of range safety of launch vehicles like Ariane and Vega, since it is expected that recurring costs are lower and accuracy is higher than currently existing systems like radar tracking. Range safety requires continuous information about the position and velocity of the launch vehicle to quickly detect the occurrence of catastrophic events. However, GNSS outages due, for example, to high jerks at fairing and stage jettisons or other external interferences like (un-)intentional jamming cannot be precluded. The OCAM-G experiment on Ariane 5 flight VA219 has provided evidence that GNSS is capable of providing a highly accurate position and velocity solution during most of the flight, but that outages of several seconds do occur. To increase the continuity of a GNSS-based localization system, it is proposed that the GNSS receiver is augmented by an inertial measurement unit (IMU), which is able to output a position and velocity solution even during GNSS outages. Since these outages are expected to be short, a tactical- or even consumer-grade IMU is expected to be sufficient. In this paper, the minimum IMU performance that is required to bridge outages of up to 10 s, and thereby meeting the accuracy requirements of range safety, is determined by means of a thorough simulation study. The focus of the analysis is on current generation microelectromechanical system (MEMS)-based IMU, which is lightweight, low-cost, available commercially and has reached acceptable maturity in the last decade.

  5. Adaptive fuzzy tracking control for a constrained flexible air-breathing hypersonic vehicle based on actuator compensation

    Directory of Open Access Journals (Sweden)

    Peng Fei Wang

    2016-10-01

    Full Text Available The design of an adaptive fuzzy tracking control for a flexible air-breathing hypersonic vehicle with actuator constraints is discussed. Based on functional decomposition methodology, velocity and altitude controllers are designed. Fuzzy logic systems are applied to approximate the lumped uncertainty of each subsystem of air-breathing hypersonic vehicle model. Every controllers contain only one adaptive parameter that needs to be updated online with a minimal-learning-parameter scheme. The back-stepping design is not demanded by converting the altitude subsystem into the normal output-feedback formulation, which predigests the design of a controller. The special contribution is that novel auxiliary systems are developed to compensate both the tracking errors and desired control laws, based on which the explored controller can still provide effective tracking of velocity and altitude commands when the inputs are saturated. Finally, reference trajectory tracking simulation shows the effectiveness of the proposed method in its application to air-breathing hypersonic vehicle control.

  6. Investigation on a Power Coupling Steering System for Dual-Motor Drive Tracked Vehicles Based on Speed Control

    Directory of Open Access Journals (Sweden)

    Li Zhai

    2017-08-01

    Full Text Available Double-motor drive tracked vehicles (2MDTV are widely used in the tracked vehicle industry due to the development of electric vehicle drive systems. The aim of this paper is to solve the problem of insufficient propulsion motor torque in low-speed, small-radius steering and insufficient power in high-speed large-radius steering. In order to do this a new type of steering system with a coupling device is designed and a closed-loop control strategy based on speed is adopted to improve the lateral stability of the vehicle. The work done entails modeling and simulating the 2MDTV and the proposed control strategy in RecurDyn and Matlab/Simulink. The simulation results show that the 2MDTV with the coupling device outputs more torque and power in both steering cases compared to the 2MDTV without the coupling device, and the steering stability of the vehicle is improved by using the strategy based on speed.

  7. Asymptotic Vision-Based Tracking Control of the Quadrotor Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Hamed Jabbari Asl

    2015-01-01

    Full Text Available This paper proposes an image-based visual servo (IBVS controller for the 3D translational motion of the quadrotor unmanned aerial vehicles (UAV. The main purpose of this paper is to provide asymptotic stability for vision-based tracking control of the quadrotor in the presence of uncertainty in the dynamic model of the system. The aim of the paper also includes the use of flow of image features as the velocity information to compensate for the unreliable linear velocity data measured by accelerometers. For this purpose, the mathematical model of the quadrotor is presented based on the optic flow of image features which provides the possibility of designing a velocity-free IBVS controller with considering the dynamics of the robot. The image features are defined from a suitable combination of perspective image moments without using the model of the object. This property allows the application of the proposed controller in unknown places. The controller is robust with respect to the uncertainties in the translational dynamics of the system associated with the target motion, image depth, and external disturbances. Simulation results and a comparison study are presented which demonstrate the effectiveness of the proposed approach.

  8. Tracked Vehicle Dynamics Modeling and Simulation Methodology, with Control, using RecurDyn Software Package

    Science.gov (United States)

    2011-09-01

    track segment, with pins connecting each track segment. The modeler must align each segment properly with the track pins with the sprocket teeth and...representative track segment is copied and linked together using a simplified algorithm which assumes each track segment is identical, with force/ torque pairs...simulation, RecurDyn feeds CoLink the desired inputs (error term, speed, direction, etc), CoLink performs the programmed operation (generates torque

  9. Satellite-based terrestrial production efficiency modeling

    Directory of Open Access Journals (Sweden)

    Obersteiner Michael

    2009-09-01

    Full Text Available Abstract Production efficiency models (PEMs are based on the theory of light use efficiency (LUE which states that a relatively constant relationship exists between photosynthetic carbon uptake and radiation receipt at the canopy level. Challenges remain however in the application of the PEM methodology to global net primary productivity (NPP monitoring. The objectives of this review are as follows: 1 to describe the general functioning of six PEMs (CASA; GLO-PEM; TURC; C-Fix; MOD17; and BEAMS identified in the literature; 2 to review each model to determine potential improvements to the general PEM methodology; 3 to review the related literature on satellite-based gross primary productivity (GPP and NPP modeling for additional possibilities for improvement; and 4 based on this review, propose items for coordinated research. This review noted a number of possibilities for improvement to the general PEM architecture - ranging from LUE to meteorological and satellite-based inputs. Current PEMs tend to treat the globe similarly in terms of physiological and meteorological factors, often ignoring unique regional aspects. Each of the existing PEMs has developed unique methods to estimate NPP and the combination of the most successful of these could lead to improvements. It may be beneficial to develop regional PEMs that can be combined under a global framework. The results of this review suggest the creation of a hybrid PEM could bring about a significant enhancement to the PEM methodology and thus terrestrial carbon flux modeling. Key items topping the PEM research agenda identified in this review include the following: LUE should not be assumed constant, but should vary by plant functional type (PFT or photosynthetic pathway; evidence is mounting that PEMs should consider incorporating diffuse radiation; continue to pursue relationships between satellite-derived variables and LUE, GPP and autotrophic respiration (Ra; there is an urgent need for

  10. Adaptive Correlation Space Adjusted Open-Loop Tracking Approach for Vehicle Positioning with Global Navigation Satellite System in Urban Areas.

    Science.gov (United States)

    Ruan, Hang; Li, Jian; Zhang, Lei; Long, Teng

    2015-08-28

    For vehicle positioning with Global Navigation Satellite System (GNSS) in urban areas, open-loop tracking shows better performance because of its high sensitivity and superior robustness against multipath. However, no previous study has focused on the effects of the code search grid size on the code phase measurement accuracy of open-loop tracking. Traditional open-loop tracking methods are performed by the batch correlators with fixed correlation space. The code search grid size, which is the correlation space, is a constant empirical value and the code phase measuring accuracy will be largely degraded due to the improper grid size, especially when the signal carrier-to-noise density ratio (C/N₀) varies. In this study, the Adaptive Correlation Space Adjusted Open-Loop Tracking Approach (ACSA-OLTA) is proposed to improve the code phase measurement dependent pseudo range accuracy. In ACSA-OLTA, the correlation space is adjusted according to the signal C/N₀. The novel Equivalent Weighted Pseudo Range Error (EWPRE) is raised to obtain the optimal code search grid sizes for different C/N₀. The code phase measuring errors of different measurement calculation methods are analyzed for the first time. The measurement calculation strategy of ACSA-OLTA is derived from the analysis to further improve the accuracy but reduce the correlator consumption. Performance simulation and real tests confirm that the pseudo range and positioning accuracy of ASCA-OLTA are better than the traditional open-loop tracking methods in the usual scenarios of urban area.

  11. Optimization Design of Double-parameter Shift Schedule of Tracked Vehicle with Hydrodynamic-mechanical Transmission%Optimization Design of Double-parameter Shift Schedule of Tracked Vehicle with Hydrodynamic-mechanical Transmission

    Institute of Scientific and Technical Information of China (English)

    武景燕; 魏巍; 曲婧瑶; 闫清东

    2011-01-01

    A kind of automatic shift schedule optimization method is provided for a tracked vehicle with hydrodynamic-mechanical transmission in order to improve its dynamic performance. A dynamic model of integrated hydrodynamic-mechanical transmission is built in MATLAB/Simdriveline environment, and an optimum shift schedule is derived by using iSight software to call the dynamic model above, then the shift schedule is achieved after optimization. The simulation results show that the method is significant to improve the dynamic performance and gear-shifting smoothness theoretically and practically.

  12. Reference Command Tracking for a Linearized Model of an Air-Breathing Hypersonic Vehicle

    Science.gov (United States)

    2005-08-01

    developed directly; for the second one, the tracking problem is cast into a regulation problem , to which LQR design can be applied. The linear quadratic...be pursued. It involves casting the tracking problem into a regulation problem and then designing a stabilizing controller using LQR techniques. The

  13. Wear mechanism of heavy load friction contact pairs in tracked vehicle by combined ferrography and surface analysis

    Institute of Scientific and Technical Information of China (English)

    LI Li; ZHU You-li; HUANG Yuan-lin; XU Bin-shi; LI Xiao-yan

    2004-01-01

    Ferrography is deemed as one of the most effective methods for wear particle analysis and failure diagnosis. By analyzing the configuration, content and composition of wear particles in the lubricanting grease and the surface state of the worn surface with combined ferrography and surface analysis techniques, the wear mechanism of the ball groove of the master clutch's release device of a heavy load tracked vehicle was determined. Results show that the controlling wear mechanism is combined of abrasion, adhesion, contact fatigue and corrosion wear, which demonstrates the effectiveness of using combined ferrography and worn surface analysis for the study of wear mechanism of contact surface with friction.

  14. AFSC/ABL: Autonomous underwater vehicle for tracking acoustically-tagged fish 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Autonomous underwater vehicles (AUVs) are increasingly being used to collect physical, chemical, and biological information in the marine environment. Recent efforts...

  15. Flexible Low Cost Avionics for NanoSatellite Launch Vehicle Control and GPS Metric Tracking Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposal, Tyvak Nano-Satellite Systems LLC (Tyvak) will develop nano-launch vehicle avionics solutions based on the latest commercial electronics products...

  16. Satellite-Based Sunshine Duration for Europe

    Directory of Open Access Journals (Sweden)

    Bodo Ahrens

    2013-06-01

    Full Text Available In this study, two different methods were applied to derive daily and monthly sunshine duration based on high-resolution satellite products provided by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT Satellite Application Facility on Climate Monitoring using data from Meteosat Second Generation (MSG SEVIRI (Spinning Enhanced Visible and Infrared Imager. The satellite products were either hourly cloud type or hourly surface incoming direct radiation. The satellite sunshine duration estimates were not found to be significantly different using the native 15-minute temporal resolution of SEVIRI. The satellite-based sunshine duration products give additional spatial information over the European continent compared with equivalent in situ-based products. An evaluation of the satellite sunshine duration by product intercomparison and against station measurements was carried out to determine their accuracy. The satellite data were found to be within ±1 h/day compared to high-quality Baseline Surface Radiation Network or surface synoptic observations (SYNOP station measurements. The satellite-based products differ more over the oceans than over land, mainly because of the treatment of fractional clouds in the cloud type-based sunshine duration product. This paper presents the methods used to derive the satellite sunshine duration products and the performance of the different retrievals. The main benefits and disadvantages compared to station-based products are also discussed.

  17. Desain Kontrol Tracking Underactuated Autonomous Underwater Vehicle (AUV dengan Pengaruh Gangguan Arus Laut

    Directory of Open Access Journals (Sweden)

    Ilmi Rizki I

    2016-11-01

    Full Text Available Paper ini membahas masalah gerak AUV pada bidang horizontal yang dipengaruhi oleh arah sudut yaw. Arah sudut yaw merupakan ukuran utama dalam mengatur gerak horizontal pada AUV. Pengaturan gerak pada AUV berupa perubahan arah sudut yaw merupakan permasalahan kontrol tracking AUV. Kontrol tracking pada paper ini digunakan untuk kebutuhan heading control. Heading control tersebut digunakan untuk mengatur arah sudut yaw AUV agar sesuai dengan sinyal referensi yaw yang diberikan. Kompleksitas dalam mendesain heading control akibat karakteristik-karakteristik dari dinamika AUV yang high nonlinear dan uncertainty parameter yang ditentukan oleh hydrodynamic forces dan environmental forces berupa gangguan ocean current menjadi permasalahan yang tidak mudah dipecahkan. Oleh karena itu dibutuhkan sebuah metode untuk mengatasi permasalahan tersebut, yaitu menggunaan metode State Dependent Riccati Equations berdasarkan Linear Quadratic Tracking (SDRE-LQT. Algoritma ini menghitung perubahan permasalahan tracking pada sudut yaw dan dapat mengatasi gangguan ocean current melalui perhitungan perubahan parameter dari AUV secara online melalui algebraic Riccati equation.sehingga sinyal kontrol yang diberikan ke plant dapat mengikuti perubahan kondisi dari plant itu sendiri, termasuk perubahan parameter akibat gangguan berupa ocean current. Hasil simulasi menunjukkan bahwa metode kontrol yang digunakan mampu membawa sudut yaw pada nilai yang diharapkan dan gangguan arus dapat diatasi dengan memberikan nilai sinyal kontrol yang baru secara online, sehingga AUV dapat melakukan  tracking secara otomatis pada kondisi ada atau tanpa gangguan ocean current dengan dengan nilai error steady state . Kata kunci — AUV, Tracking Control, SDRE-LQT, Ocean Current Disturbance

  18. Finite Element Analysis for the Structure Optimization Design of the CPUE Load-Bearing Wheel of Tracked Vehicle

    Institute of Scientific and Technical Information of China (English)

    于立彪; 郑慕侨; 张英

    2003-01-01

    A new kind of material cast polyurethane elastomers (CPUE) is introduced to take the place of rubber on load-bearing wheel for the first time. Based on load-bearing wheel dimensions, material properties and operating conditions, the structure of wheel flange is optimized by zero-order finite element method. A detailed three-dimensional finite element model of flange of load-bearing wheel is developed and utilized to optimize structure of wheel flange. Its service life, which is affected by flange structure parameter, is analyzed by comparing the optimization results with those of prototype of wheel. The results of optimization are presented and the stress field of load-bearing wheel in optimal dimension obtained by using finite element analysis method is demonstrated. The finite element analysis and optimization results show that the CPUE load-bearing wheel is feasible and suitable for the tracked vehicle and has a guiding value in practice of the weighting design of the whole tracked vehicle.

  19. Adaptive Correlation Space Adjusted Open-Loop Tracking Approach for Vehicle Positioning with Global Navigation Satellite System in Urban Areas

    Directory of Open Access Journals (Sweden)

    Hang Ruan

    2015-08-01

    Full Text Available For vehicle positioning with Global Navigation Satellite System (GNSS in urban areas, open-loop tracking shows better performance because of its high sensitivity and superior robustness against multipath. However, no previous study has focused on the effects of the code search grid size on the code phase measurement accuracy of open-loop tracking. Traditional open-loop tracking methods are performed by the batch correlators with fixed correlation space. The code search grid size, which is the correlation space, is a constant empirical value and the code phase measuring accuracy will be largely degraded due to the improper grid size, especially when the signal carrier-to-noise density ratio (C/N0 varies. In this study, the Adaptive Correlation Space Adjusted Open-Loop Tracking Approach (ACSA-OLTA is proposed to improve the code phase measurement dependent pseudo range accuracy. In ACSA-OLTA, the correlation space is adjusted according to the signal C/N0. The novel Equivalent Weighted Pseudo Range Error (EWPRE is raised to obtain the optimal code search grid sizes for different C/N0. The code phase measuring errors of different measurement calculation methods are analyzed for the first time. The measurement calculation strategy of ACSA-OLTA is derived from the analysis to further improve the accuracy but reduce the correlator consumption. Performance simulation and real tests confirm that the pseudo range and positioning accuracy of ASCA-OLTA are better than the traditional open-loop tracking methods in the usual scenarios of urban area.

  20. Feature selection for appearance-based vehicle tracking in geospatial video

    Science.gov (United States)

    Poostchi, Mahdieh; Bunyak, Filiz; Palaniappan, Kannappan; Seetharaman, Guna

    2013-05-01

    Current video tracking systems often employ a rich set of intensity, edge, texture, shape and object level features combined with descriptors for appearance modeling. This approach increases tracker robustness but is compu- tationally expensive for realtime applications and localization accuracy can be adversely affected by including distracting features in the feature fusion or object classification processes. This paper explores offline feature subset selection using a filter-based evaluation approach for video tracking to reduce the dimensionality of the feature space and to discover relevant representative lower dimensional subspaces for online tracking. We com- pare the performance of the exhaustive FOCUS algorithm to the sequential heuristic SFFS, SFS and RELIEF feature selection methods. Experiments show that using offline feature selection reduces computational complex- ity, improves feature fusion and is expected to translate into better online tracking performance. Overall SFFS and SFS perform very well, close to the optimum determined by FOCUS, but RELIEF does not work as well for feature selection in the context of appearance-based object tracking.

  1. Tracking of Vehicle Movement on a Parking Lot Based on Video Detection

    Directory of Open Access Journals (Sweden)

    Ján HALGAŠ

    2014-06-01

    Full Text Available This article deals with topic of transport vehicles identification for dynamic and static transport based on video detection. It explains some of the technologies and approaches necessary for processing of specific image information (transport situation. The paper also describes a design of algorithm for vehicle detection on parking lot and consecutive record of trajectory into virtual environment. It shows a new approach to moving object detection (vehicles, people, and handlers on an enclosed area with emphasis on secure parking. The created application enables automatic identification of trajectory of specific objects moving within the parking area. The application was created in program language C++ with using an open source library OpenCV.

  2. Multi-sensor field trials for detection and tracking of multiple small unmanned aerial vehicles flying at low altitude

    Science.gov (United States)

    Laurenzis, Martin; Hengy, Sebastien; Hommes, Alexander; Kloeppel, Frank; Shoykhetbrod, Alex; Geibig, Thomas; Johannes, Winfried; Naz, Pierre; Christnacher, Frank

    2017-05-01

    Small unmanned aerial vehicles (UAV) flying at low altitude are becoming more and more a serious threat in civilian and military scenarios. In recent past, numerous incidents have been reported where small UAV were flying in security areas leading to serious danger to public safety or privacy. The detection and tracking of small UAV is a widely discussed topic. Especially, small UAV flying at low altitude in urban environment or near background structures and the detection of multiple UAV at the same time is challenging. Field trials were carried out to investigate the detection and tracking of multiple UAV flying at low altitude with state of the art detection technologies. Here, we present results which were achieved using a heterogeneous sensor network consisting of acoustic antennas, small frequency modulated continuous wave (FMCW) RADAR systems and optical sensors. While acoustics, RADAR and LiDAR were applied to monitor a wide azimuthal area (360°) and to simultaneously track multiple UAV, optical sensors were used for sequential identification with a very narrow field of view.

  3. Autonomous underwater vehicle motion tracking using a Kalman filter for sensor fusion

    CSIR Research Space (South Africa)

    Holtzhausen, S

    2008-11-01

    Full Text Available to be discussed is the IMU. This sensor system consists of three accelerometers and three gyros. The accelerometers are positioned on the X, Y and Z axes and measure acceleration in their respective directions. 15th International conference on Mechatronics... of the vehicle. The accelerometer data can be used to determine linear motion by calculating the double integral of the accelerometer data over time. This will give the calculated movement of the vehicle in the given direction. The accelerometer data can also...

  4. Dynamic Modeling and Control Strategy Optimization for a Hybrid Electric Tracked Vehicle

    Directory of Open Access Journals (Sweden)

    Hong Wang

    2015-01-01

    Full Text Available A new hybrid electric tracked bulldozer composed of an engine generator, two driving motors, and an ultracapacitor is put forward, which can provide high efficiencies and less fuel consumption comparing with traditional ones. This paper first presents the terramechanics of this hybrid electric tracked bulldozer. The driving dynamics for this tracked bulldozer is then analyzed. After that, based on analyzing the working characteristics of the engine, generator, and driving motors, the power train system model and control strategy optimization is established by using MATLAB/Simulink and OPTIMUS software. Simulation is performed under a representative working condition, and the results demonstrate that fuel economy of the HETV can be significantly improved.

  5. China’s vehicle products export on the fast track (Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A total of 340,000 vehicles were exported in 2006, a year on year growth of 99 percent, including 93,000 cars, or a year on year up of 200 percent. The export market also managed to expand its deficit formed in 2005 to up to USD 7.636 billion.

  6. Autonomous underwater vehicle motion tracking using a Kalman Filter for sensor fusion

    CSIR Research Space (South Africa)

    Holtzhausen, S

    2008-01-01

    Full Text Available AUVs are ideal platforms for search and rescue operations. They can also be used for inspection of underwater terrains. These vehicles need to be autonomous and robust to cope with unpredictable current and high pressures. In this paper...

  7. THE STUDY OF THE RAILWAY VEHICLES MOVEMENT ON CURVED TRACK SECTIONS

    Directory of Open Access Journals (Sweden)

    N. A. Radchenko

    2009-07-01

    Full Text Available The results of studies of motion of the rail transport facilities on circular and transition curves are prersented. In particular the questions of vibrations, stationary modes, stability and safety of coach, locomotive and transporter motion not only on straight-line but on curvilinear sections of the railway track are considered.

  8. Efficient integration of spectral features for vehicle tracking utilizing an adaptive sensor

    Science.gov (United States)

    Uzkent, Burak; Hoffman, Matthew J.; Vodacek, Anthony

    2015-03-01

    Object tracking in urban environments is an important and challenging problem that is traditionally tackled using visible and near infrared wavelengths. By inserting extended data such as spectral features of the objects one can improve the reliability of the identification process. However, huge increase in data created by hyperspectral imaging is usually prohibitive. To overcome the complexity problem, we propose a persistent air-to-ground target tracking system inspired by a state-of-the-art, adaptive, multi-modal sensor. The adaptive sensor is capable of providing panchromatic images as well as the spectra of desired pixels. This addresses the data challenge of hyperspectral tracking by only recording spectral data as needed. Spectral likelihoods are integrated into a data association algorithm in a Bayesian fashion to minimize the likelihood of misidentification. A framework for controlling spectral data collection is developed by incorporating motion segmentation information and prior information from a Gaussian Sum filter (GSF) movement predictions from a multi-model forecasting set. An intersection mask of the surveillance area is extracted from OpenStreetMap source and incorporated into the tracking algorithm to perform online refinement of multiple model set. The proposed system is tested using challenging and realistic scenarios generated in an adverse environment.

  9. The single-track road running parallel to the D884 dual carriageway in the Pays de Gex is now closed to motor vehicles

    CERN Multimedia

    DSU Department

    2008-01-01

    The French authorities have informed CERN that, once the corresponding road signs have been installed, the single-track road running parallel to the dual carriageway culminating at Gate E will be closed to all motorised vehicle traffic, with the exception of agricultural plant, motorcycles, and service, emergency and police vehicles. Relations with the Host States Service Tel.: 72848 mailto:relations.secretariat@cern.chhttp://www.cern.ch/relations

  10. Nonlinear Constrained Adaptive Backstepping Tracking Control for a Hypersonic Vehicle with Uncertainty

    Directory of Open Access Journals (Sweden)

    Qin Zou

    2015-01-01

    Full Text Available The control problem of a flexible hypersonic vehicle is presented, where input saturation and aerodynamic uncertainty are considered. A control-oriented model including aerodynamic uncertainty is derived for simple controller design due to the nonlinearity and complexity of hypersonic vehicle model. Then it is separated into velocity subsystem and altitude subsystem. On the basis of the integration of robust adaptive control and backstepping technique, respective controller is designed for each subsystem, where an auxiliary signal provided by an additional dynamic system is used to compensate for the control saturation effect. Then to deal with the “explosion of terms” problem inherent in backstepping control, a novel first-order filter is proposed. Simulation results are included to demonstrate the effectiveness of the adaptive backstepping control scheme.

  11. Path Planning of Unmanned Aerial Vehicles With Terrestrial Wireless Network Tracking

    OpenAIRE

    Bekhti, Mustapha; Abdennebi, Marwen; Achir, Nadjib; Boussetta, Khaled

    2016-01-01

    International audience; The UAVs (Unmanned Aerial Vehicles) market is projected to grow, sustained by the technological progress in different domains related to UAVs and by the emergence of new civilian applications. However, this economical development might be held back due to increased regulation constraints. A major concern of public authorities is to ensure a safe sharing of the airspace, especially over populated areas. To reach this aim, a fundamental mechanism is to provide a permanen...

  12. Vehicle Dynamics Monitoring and Tracking System (VDMTS): Monitoring Mission Impacts in Support of Installation Land Management

    Science.gov (United States)

    2012-06-01

    performed using multiple vehicles at Fort Ri- ley , PTA, and Eglin AFB. The theoretical model results were compared with measured impact values. Additionally...Sample Conversions: $BB209 = -178.75°/s $ESOF2 = 0.806 g $H80BC = 0.094 gauss $J800D = 26.82 OC $S87FE = 4.95 1 V $IBF30 = -0.1 gauss l0004D295

  13. Optimal UAV Path Planning for Tracking a Moving Ground Vehicle with a Gimbaled Camera

    Science.gov (United States)

    2014-03-27

    105 vii List of Figures Figure Page 2.1. Sig Rascal 110 . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.2. Arduino ...necessary baseline for flight testing autonomous UAV convoy tracking. Figure 2.2: Arduino Autopilot - APM 2.5 [1] The APM is an open source autopilot...a C-based programming language and comes with a cor- 21 responding programming environment called Arduino IDE [1]. Within the Arduino IDE, all of the

  14. Tracking Control of Autonomous Underwater Vehicles with Internal Moving Mass%自主水下航行器的变质心跟踪控制

    Institute of Scientific and Technical Information of China (English)

    李家旺; 宋保维; 邵成

    2008-01-01

    The trajectory-tracking control problem is inves-tigated for an autonomous underwater vehicle (AUV) moving in the vertical plane using an internal point mass and a rear thruster as actuators. Combined with the dynamics of the point mass, the AUV is modeled as an underactuated system. A Lyapunov-based tracking controller is proposed by using back-stepping approach to stabilize the error dynamics and forcc the position errors to a small neighborhood of thc origin. Simulation results validate the proposcd tracking approach.

  15. Dynamic vehicle-track interaction in switches and crossings and the influence of rail pad stiffness - field measurements and validation of a simulation model

    Science.gov (United States)

    Pålsson, Björn A.; Nielsen, Jens C. O.

    2015-06-01

    A model for simulation of dynamic interaction between a railway vehicle and a turnout (switch and crossing, S&C) is validated versus field measurements. In particular, the implementation and accuracy of viscously damped track models with different complexities are assessed. The validation data come from full-scale field measurements of dynamic track stiffness and wheel-rail contact forces in a demonstrator turnout that was installed as part of the INNOTRACK project with funding from the European Union Sixth Framework Programme. Vertical track stiffness at nominal wheel loads, in the frequency range up to 20 Hz, was measured using a rolling stiffness measurement vehicle (RSMV). Vertical and lateral wheel-rail contact forces were measured by an instrumented wheel set mounted in a freight car featuring Y25 bogies. The measurements were performed for traffic in both the through and diverging routes, and in the facing and trailing moves. The full set of test runs was repeated with different types of rail pad to investigate the influence of rail pad stiffness on track stiffness and contact forces. It is concluded that impact loads on the crossing can be reduced by using more resilient rail pads. To allow for vehicle dynamics simulations at low computational cost, the track models are discretised space-variant mass-spring-damper models that are moving with each wheel set of the vehicle model. Acceptable agreement between simulated and measured vertical contact forces at the crossing can be obtained when the standard GENSYS track model is extended with one ballast/subgrade mass under each rail. This model can be tuned to capture the large phase delay in dynamic track stiffness at low frequencies, as measured by the RSMV, while remaining sufficiently resilient at higher frequencies.

  16. Framework for performance evaluation of face, text, and vehicle detection and tracking in video: data, metrics, and protocol.

    Science.gov (United States)

    Kasturi, Rangachar; Goldgof, Dmitry; Soundararajan, Padmanabhan; Manohar, Vasant; Garofolo, John; Bowers, Rachel; Boonstra, Matthew; Korzhova, Valentina; Zhang, Jing

    2009-02-01

    Common benchmark data sets, standardized performance metrics, and baseline algorithms have demonstrated considerable impact on research and development in a variety of application domains. These resources provide both consumers and developers of technology with a common framework to objectively compare the performance of different algorithms and algorithmic improvements. In this paper, we present such a framework for evaluating object detection and tracking in video: specifically for face, text, and vehicle objects. This framework includes the source video data, ground-truth annotations (along with guidelines for annotation), performance metrics, evaluation protocols, and tools including scoring software and baseline algorithms. For each detection and tracking task and supported domain, we developed a 50-clip training set and a 50-clip test set. Each data clip is approximately 2.5 minutes long and has been completely spatially/temporally annotated at the I-frame level. Each task/domain, therefore, has an associated annotated corpus of approximately 450,000 frames. The scope of such annotation is unprecedented and was designed to begin to support the necessary quantities of data for robust machine learning approaches, as well as a statistically significant comparison of the performance of algorithms. The goal of this work was to systematically address the challenges of object detection and tracking through a common evaluation framework that permits a meaningful objective comparison of techniques, provides the research community with sufficient data for the exploration of automatic modeling techniques, encourages the incorporation of objective evaluation into the development process, and contributes useful lasting resources of a scale and magnitude that will prove to be extremely useful to the computer vision research community for years to come.

  17. Effectiveness of a Program Using a Vehicle Tracking System, Incentives, and Disincentives to Reduce the Speeding Behavior of Drivers with ADHD

    Science.gov (United States)

    Markham, Paula T.; Porter, Bryan E.; Ball, J. D.

    2013-01-01

    Objective: In this article, the authors investigated the effectiveness of a behavior modification program using global positioning system (GPS) vehicle tracking devices with contingency incentives and disincentives to reduce the speeding behavior of drivers with ADHD. Method: Using an AB multiple-baseline design, six participants drove a 5-mile…

  18. Tracking control of a class of non-linear systems with applications to cruise control of air-breathing hypersonic vehicles

    Science.gov (United States)

    Sun, Hongfei; Yang, Zhiling; Meng, Bin

    2015-05-01

    A new tracking-control method for general non-linear systems is proposed. A virtual controller and some command references are introduced to asymptotically stabilise the system of the tracking error dynamics. Then, the actual controller and command references are derived by solving a system of linear algebraic equations. Compared with other tracking-control methods in the literature, the tracking-controller design in this paper is simple because it needs only to solve a system of linear algebraic equations. The boundedness of the tracking controller and command references is guaranteed by the solvability of the terminal value problem (TVP) of an ordinary differential equation. For non-linear systems with minimum-phase properties, the TVP is automatically solvable. A numerical example shows that the tracking-control method is still available for some systems with non-minimum-phase properties. To enhance the robustness of the tracking controller, a non-linear disturbance observer (NDO) is introduced to estimate the disturbance. The combination of the tracking controller and the NDO is applied to the tracking control of an air-breathing hypersonic vehicle.

  19. 履带式车辆斜坡匀速转向特性分析%Analysis on Uniform Steering of Tracked Vehicles on Ramp

    Institute of Scientific and Technical Information of China (English)

    张战文; 杨福增; 张季琴

    2011-01-01

    根据履带式车辆的运动特点,运用数力学理论,分别对履带式车辆在纵向和横向坡道上的匀速转向特性进行了分析,并在此基础上着重研究了地面纵向坡度、横向坡度对履带式车辆匀速转向的影响,即重力的纵向分力、横向分力对匀速转向的影响,研究在这些外力作用下,履带式车辆的转向运动规律,从而得出履带式车辆转向的最困难条件,为进行转向牵引计算和转向机构强度设计提供根据。%According to the moving characteristics of tracked vehicles,using several mechanics theory,the steering characteristics of tracked vehicles on longitudinal and transverse ramps are respectively analyzed,and based on this study,the influences of longitudinal and transverse ramp on uniform steering for tracked vehicles are particularly studied,that's to say,influences of gravity's longitudinal and transverse force on uniform steering.The steering movement rules of tracked vehicles are obtained under the condition of these outside forces,then the most difficult condition during tracked vehicle steering are also obtained,and which can provide a foundation for steering calculation and strength design of steering mechanism.

  20. Development of SPIES (Space Intelligent Eyeing System) for smart vehicle tracing and tracking

    Science.gov (United States)

    Abdullah, Suzanah; Ariffin Osoman, Muhammad; Guan Liyong, Chua; Zulfadhli Mohd Noor, Mohd; Mohamed, Ikhwan

    2016-06-01

    SPIES or Space-based Intelligent Eyeing System is an intelligent technology which can be utilized for various applications such as gathering spatial information of features on Earth, tracking system for the movement of an object, tracing system to trace the history information, monitoring driving behavior, security and alarm system as an observer in real time and many more. SPIES as will be developed and supplied modularly will encourage the usage based on needs and affordability of users. SPIES are a complete system with camera, GSM, GPS/GNSS and G-Sensor modules with intelligent function and capabilities. Mainly the camera is used to capture pictures and video and sometimes with audio of an event. Its usage is not limited to normal use for nostalgic purpose but can be used as a reference for security and material of evidence when an undesirable event such as crime occurs. When integrated with space based technology of the Global Navigational Satellite System (GNSS), photos and videos can be recorded together with positioning information. A product of the integration of these technologies when integrated with Information, Communication and Technology (ICT) and Geographic Information System (GIS) will produce innovation in the form of information gathering methods in still picture or video with positioning information that can be conveyed in real time via the web to display location on the map hence creating an intelligent eyeing system based on space technology. The importance of providing global positioning information is a challenge but overcome by SPIES even in areas without GNSS signal reception for the purpose of continuous tracking and tracing capability

  1. Quaternion-based nonlinear trajectory tracking control of a quadrotor unmanned aerial vehicle

    Science.gov (United States)

    Zha, Changliu; Ding, Xilun; Yu, Yushu; Wang, Xueqiang

    2017-01-01

    At present, most controllers of quadrotor unmanned aerial vehicles(UAVs) use Euler angles to express attitude. These controllers suffer a singularity problem when the pitch angle is near 90°C, which limits the maneuverability of the UAV. To overcome this problem, based on the quaternion attitude representation, a 6 degree of freedom(DOF) nonlinear controller of a quadrotor UAV is designed using the trajectory linearization control(TLC) method. The overall controller contains a position sub-controller and an attitude sub-controller. The two controllers regulate the translational and rotational motion of the UAV, respectively. The controller is improved by using the commanded value instead of the nominal value as the input of the inner control loop. The performance of controller is tested by simulation before and after the improvement, the results show that the improved controller is better. The proposed controller is also tested via numerical simulation and real flights and is compared with the traditional controller based on Euler angles. The test results confirm the feasibility and the robustness of the proposed nonlinear controller. The proposed controller can successfully solve the singularity problem that usually occurs in the current attitude control of UAV and it is easy to be realized.

  2. Analysis of recurring sinking events of armored tracked vehicles along dirt roads in the agricultural periphery of the Gaza Strip

    Science.gov (United States)

    Roskin, Joel

    2013-04-01

    The second (Al-Aqsa) intifada (Arab violent uprising) which erupted across Israel in 2000 eventually led the Israel Defense Forces to deploy armored tracked vehicles (ATVs) (tanks, armored personal carriers, and D-9 bulldozers) within Israel's agricultural periphery of the Gaza Strip, following daily attempts by Arab terrorists and guerillas to penetrate Israel. Combat movement of the ATVs was mainly concentrated to dirt roads, between agricultural fields, wherever possible. As a result of semi-arid Mediterranean (climate) winter rains, annually averaging 250 - 350 mm, it was reported that ATVs often sank in muddy terrain. This study investigated what caused ATVs to sink. The main data collected concerning the types of vehicles that sank related to: land-use characteristics, soil type, and daily rainfall. Interviews with commanders were also conducted for additional details. Between the fall and spring, surveys and weekly / bi-weekly field soil cone penetrometer tests were conducted at ten sites with different pedological and land-use characteristics. The loess soils, especially in agricultural fields, were generally found to be conducive to ATV traffic, even shortly after rainstorms of 10-30 mm. However, following several rainfall events exceeding 10 mm, ATVs and tanks regularly sank into local topographic depressions in the undulating landscape. These consisted of short segments of dirt roads where runoff and suspended sediment collected. After the early rains in late fall, tank ruts fossilize and become conduits of concentrated runoff and fine particles eroded by ATV activity during the summer months. Tank track ruts that formed in mud, compacted the soil, drastically altered drainage patterns by directing significant surface flow, and suspended sediment into these depressions, creating "tank-traps" whose trafficability ranged from "untrafficable" to "trafficable with constraints." This study shows that intense, routine, defensive military activity operated

  3. Tracking Forest and Open Area Effects on Snow Accumulation by Unmanned Aerial Vehicle Photogrammetry

    Science.gov (United States)

    Lendzioch, T.; Langhammer, J.; Jenicek, M.

    2016-06-01

    Airborne digital photogrammetry is undergoing a renaissance. The availability of low-cost Unmanned Aerial Vehicle (UAV) platforms well adopted for digital photography and progress in software development now gives rise to apply this technique to different areas of research. Especially in determining snow depth spatial distributions, where repetitive mapping of cryosphere dynamics is crucial. Here, we introduce UAV-based digital photogrammetry as a rapid and robust approach for evaluating snow accumulation over small local areas (e.g., dead forest, open areas) and to reveal impacts related to changes in forest and snowpack. Due to the advancement of the technique, snow depth of selected study areas such as of healthy forest, disturbed forest, succession, dead forest, and of open areas can be estimated at a 1 cm spatial resolution. The approach is performed in two steps: 1) developing a high resolution Digital Elevation Model during snow-free and 2) during snow-covered conditions. By substracting these two models the snow depth can be accurately retrieved and volumetric changes of snow depth distribution can be achieved. This is a first proof-of-concept study combining snow depth determination and Leaf Area Index (LAI) retrieval to monitor the impact of forest canopy metrics on snow accumulation in coniferous forest within the Šumava National Park, Czech Republic. Both, downward-looking UAV images and upward-looking LAI-2200 canopy analyser measurements were applied to reveal the LAI, controlling interception and transmitting radiation. For the performance of downward-looking images the snow background instead of the sky fraction was used. In contrast to the classical determination of LAI by hemispherical photography or by LAI plant canopy analyser, our approach will also test the accuracy of LAI measurements by UAV that are taken simultaneously during the snow cover mapping campaigns. Since the LAI parameter is important for snowpack modelling, this method presents

  4. Hanford tank initiative vehicle/based waste retrieval demonstration report phase II, track 2

    Energy Technology Data Exchange (ETDEWEB)

    Berglin, E.J.

    1997-07-31

    Using the versatile TracPUMpTm, Environmental Specialties Group, LLC (ES) performed a successful Phase 11 demonstration of a Vehicle- Based Waste Retrieval System (VWRS) for removal of waste material and residual liquid found in the Hanford Underground Storage Tanks (ousts). The purpose of this demonstration was to address issues pertaining to the use of a VWRS in OUSTS. The demonstration also revealed the waste removal capabilities of the TracPumpTm and the most effective techniques and equipment to safely and effectively remove waste simulants. ES successfully addressed the following primary issues: I . Dislodge and convey the waste forms present in the Hanford OUSTS; 2. Access the UST through tank openings as small as twenty-four inches in diameter; 3. Traverse a variety of terrains including slopes, sludges, rocks and hard, slippery surfaces without becoming mired; 4. Dislodge and convey waste within the confinement of the Decontamination Containment Capture Vessel (DCCV) and with minimal personnel exposure; 5. Decontaminate equipment to acceptable limits during retrieval from the UST; 6. Perform any required maintenance within the confinement of the DCCV; and 7. Maintain contaminate levels ``as low as reasonably achievable`` (ALARA) within the DCCV due to its crevice and comer-free design. The following materials were used to simulate the physical characteristics of wastes found in Hanford`s OUSTS: (1) Hardpan: a clay-type material that has high shear strength; (2) Saltcake: a fertilizer-based material that has high compressive strength; and (3) Wet Sludge.- a sticky, peanut- butter- like material with low shear strength. Four test beds were constructed of plywood and filled with a different simulant to a depth of eight to ten inches. Three of the test beds were of homogenous simulant material, while the fourth bed consisted of a mixture of all three simulant types.

  5. Satellite-based technology, systems testing of fishing vessels: Newfoundland Region (1997) = Essais de systèmes de satellites pour les bateaux de pêche : règion de Terre-Neuve (1997)

    National Research Council Canada - National Science Library

    1998-01-01

    The application of satellite-based technology for monitoring fishing vessels and fishing activity is an effective management tool, permitting two-way communication and electronic tracking and reporting...

  6. TRACKING FOREST AND OPEN AREA EFFECTS ON SNOW ACCUMULATION BY UNMANNED AERIAL VEHICLE PHOTOGRAMMETRY

    Directory of Open Access Journals (Sweden)

    T. Lendzioch

    2016-06-01

    Full Text Available Airborne digital photogrammetry is undergoing a renaissance. The availability of low-cost Unmanned Aerial Vehicle (UAV platforms well adopted for digital photography and progress in software development now gives rise to apply this technique to different areas of research. Especially in determining snow depth spatial distributions, where repetitive mapping of cryosphere dynamics is crucial. Here, we introduce UAV-based digital photogrammetry as a rapid and robust approach for evaluating snow accumulation over small local areas (e.g., dead forest, open areas and to reveal impacts related to changes in forest and snowpack. Due to the advancement of the technique, snow depth of selected study areas such as of healthy forest, disturbed forest, succession, dead forest, and of open areas can be estimated at a 1 cm spatial resolution. The approach is performed in two steps: 1 developing a high resolution Digital Elevation Model during snow-free and 2 during snow-covered conditions. By substracting these two models the snow depth can be accurately retrieved and volumetric changes of snow depth distribution can be achieved. This is a first proof-of-concept study combining snow depth determination and Leaf Area Index (LAI retrieval to monitor the impact of forest canopy metrics on snow accumulation in coniferous forest within the Šumava National Park, Czech Republic. Both, downward-looking UAV images and upward-looking LAI-2200 canopy analyser measurements were applied to reveal the LAI, controlling interception and transmitting radiation. For the performance of downward-looking images the snow background instead of the sky fraction was used. In contrast to the classical determination of LAI by hemispherical photography or by LAI plant canopy analyser, our approach will also test the accuracy of LAI measurements by UAV that are taken simultaneously during the snow cover mapping campaigns. Since the LAI parameter is important for snowpack modelling, this

  7. Non-fragile switching tracking control for a flexible air-breathing hypersonic vehicle based on polytopic LPV model

    Institute of Scientific and Technical Information of China (English)

    Huang Yiqing; Sun Changyin; Qian Chengshan; Wang Li

    2013-01-01

    This article proposes a linear parameter varying (LPV) switching tracking control scheme for a flexible air-breathing hypersonic vehicle (FAHV).First,a polytopic LPV model is constructed to represent the complex nonlinear longitudinal model of the FAHV by using Jacobian linearization and tensor-product (T-P) model transformation approach.Second,for less conservative controller design purpose,the flight envelope is divided into four sub-regions and a non-fragile LPV controller is designed for each parameter sub-region.These non-fragile LPV controllers are then switched in order to guarantee the closed-loop FAHV system to be asymptotically stable and satisfy a specified performance criterion.The desired non-fragile LPV switching controller is found by solving a convex constraint problem which can be efficiently solved using available linear matrix inequality (LMI) techniques,and robust stability analysis of the closed-loop FAHV system is verified based on multiple Lypapunov functions (MLFs).Finally,numerical simulations have demonstrated the effectiveness of the proposed approach.

  8. Maneuvering Vehicle Tracking Based on Multi-sensor Fusion%基于多传感融合的路面机动目标跟踪

    Institute of Scientific and Technical Information of China (English)

    陈莹; 韩崇昭

    2005-01-01

    Maneuvering targets tracking is a fundamental task in intelligent vehicle research. This paper focuses on the problem of fusion between radar and image sensors in targets tracking. In order to improve positioning accuracy and narrow down the image working area, a novel method that integrates radar filter with image intensity is proposed to establish an adaptive vision window.A weighted Hausdorff distance is introduced to define the functional relationship between image and model projection, and a modified simulated annealing algorithm is used to find optimum orientation parameter. Furthermore, the global state is estimated, which refers to the distributed data fusion algorithm. Experiment results show that our method is accurate.

  9. Co-Channel Interference Mitigation Using Satellite Based Receivers

    Science.gov (United States)

    2014-12-01

    While there is some phase noise present in the continuous time-shifted signal, it is important to recognize that this signal is plotted over the [−π...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS CO-CHANNEL INTERFERENCE MITIGATION USING SATELLITE BASED RECEIVERS by John E. Patterson...07-02-2012 to 12-19-2014 4. TITLE AND SUBTITLE CO-CHANNEL INTERFERENCE MITIGATION USING SATELLITE BASED RE- CEIVERS 5. FUNDING NUMBERS 6. AUTHOR(S

  10. Integrated Navigation System for the Second Generation Reusable Launch Vehicle

    Science.gov (United States)

    2002-01-01

    An array of components in a laboratory at NASA's Marshall Space Flight Center (MSFC) is being tested by the Flight Mechanics Office to develop an integrated navigation system for the second generation reusable launch vehicle. The laboratory is testing Global Positioning System (GPS) components, a satellite-based location and navigation system, and Inertial Navigation System (INS) components, sensors on a vehicle that determine angular velocity and linear acceleration at various points. The GPS and INS components work together to provide a space vehicle with guidance and navigation, like the push of the OnStar button in your car assists you with directions to a specific address. The integration will enable the vehicle operating system to track where the vehicle is in space and define its trajectory. The use of INS components for navigation is not new to space technology. The Space Shuttle currently uses them. However, the Space Launch Initiative is expanding the technology to integrate GPS and INS components to allow the vehicle to better define its position and more accurately determine vehicle acceleration and velocity. This advanced technology will lower operational costs and enhance the safety of reusable launch vehicles by providing a more comprehensive navigation system with greater capabilities. In this photograph, Dr. Jason Chuang of MSFC inspects an INS component in the laboratory.

  11. Evaluation of an Efficient Approach for Target Tracking from Acoustic Imagery for the Perception System of an Autonomous Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Sebastián A. Villar

    2014-02-01

    Full Text Available This article describes the core algorithms of the perception system to be included within an autonomous underwater vehicle (AUV. This perception system is based on the acoustic data acquired from side scan sonar (SSS. These data should be processed in an efficient time, so that the perception system is able to detect and recognize a predefined target. This detection and recognition outcome is therefore an important piece of knowledge for the AUVs dynamic mission planner (DMP. Effectively, the DMP should propose different trajectories, navigation depths and other parameters that will change the robot's behaviour according to the perception system output. Hence, the time in which to make a decision is critical in order to assure safe robot operation and to acquire good quality data; consequently, the efficiency of the on-line image processing from acoustic data is a key issue. Current techniques for acoustic data processing are time and computationally intensive. Hence, it was decided to process data coming from a SSS using a technique that is used for radars, due to its efficiency and its amenability to on-line processing. The engineering problem to solve in this case was underwater pipeline tracking for routine inspections in the off-shore industry. Then, an automatic oil pipeline detection system was developed borrowing techniques from the processing of radar measurements. The radar technique is known as Cell Average – Constant False Alarm Rate (CA – CFAR. With a slight variation of the algorithms underlying this radar technique, which consisted of the previous accumulation of partial sums, a great improvement in computing time and effort was achieved. Finally, a comparison with previous approaches over images acquired with a SSS from a vessel in the Salvador de Bahia bay in Brazil showed the feasibility of using this on-board technique for AUV perception.

  12. Tracking multiple moving vehicles under the occlusion conditions%遮挡条件下多运动车辆跟踪研究

    Institute of Scientific and Technical Information of China (English)

    杨婷婷; 陈锋

    2015-01-01

    In order to deal with the problem that the SURF algorithm can extract only a few feature points, the histogram equalization algorithm is intruduced to hold brightness characteristics and then the image features points are extracted through the reconstruction of the SURF′s scale space. In this work,the improved method is combined with Kalman filtring algorithm to track moving vehicles,and the position is approximated using the center of the feature points. The next position of the target vehicle is predicted through Kalman filtering method and the adaptive matching window is built. Our method is used to extract the feature vectors to match the targets vehicles. The results shows that our method can track moving vehicles effectively when the target vehicle has a large rotation, scaling and partial occlusion. The track speed is higher than the R-SURF algorithm by 20%. The tracking accuracy of our method is higher than that of Kalman filtering algorithm for the same vehicle speed.%针对 SURF 算法能够提取到的图像特征点较少的问题,基于保持亮度特性的双直方图均衡算法,通过重构 SURF 尺度空间提取图像特征。将这种方法与卡尔曼滤波相结合进行目标跟踪,用特征点的中心作为跟踪点;通过卡尔曼滤波预测出运动目标的位置,判断遮挡是否发生;最后,应用该方法进行目标特征向量匹配。实验结果表明,该算法对发生旋转、缩放以及遮挡的多运动目标都可进行稳定跟踪,其跟踪速度比 R-SURF 算法提高20%;在跟踪速度相当的情况下,跟踪精度要高于卡尔曼滤波跟踪算法。

  13. Discussion on Design of Track Joining of Departure and Arrival Track of Vehicle Depot of Urban Rail Transit%轨道交通车辆段出入线接轨方案设计探索

    Institute of Scientific and Technical Information of China (English)

    高华

    2012-01-01

    研究目的:车辆段出入线接轨方案研究是轨道交通前期设计中的一个重要课题,本文通过对无锡地铁1号线西漳车辆段出入线的一站接轨方案和两站接轨方案进行比较后,从接轨站车站规模、线路条件、行车干扰程度、折返以及出段作业效率、建设投资等因素出发,综合分析,最终确定了最合理方案.研究结论:(1)出入线应本着方便运营、优化平纵断面条件,减少与正线的行车干扰,提高列车折返、出入段作业效率,降低运营成本等要素来选择合适的接轨方式.(2)在轨道交通设计中,应结合车辆段的段址,正线线路条件、车站规模,行车,运营,投资等多种因素,选择相对合理的接轨方式.有条件时可结合段型布置,实现列车调头转向功能.(3)在选择车辆段出入线的接轨方式时,应从区域规划,项目建成后的社会效益,经济效益等多方面考虑,确定最合理方案.%Research purposes:The research on the track joining of the departure and arrival track of the vehicle depot is a very important work in the prophase design. In this paper, through comprehensively analyzing and comparing the schemes for the one - station track joining and two - station track joining of the departure and arrival track of the Xizhang Vehicle Depot of Line 1 of the Wuxi metro, the analysis is made from areas of the scale of the station where the track joins, track conditions, the interference degree on the traffic, the turn -back operation, the operation efficiency of the train departing the depot and the construction investment so as to decide the most reasonable scheme.Research conclusions: The factors of the easy operation, optimization of the plane and vertical sections conditions, reduction of the traffic interference on the main track, improvement of the operation efficiencies of the train turning back and departing and arriving at the depot and reduction of the operation cost should be

  14. 直行非机动车避让右转车辆轨迹分析%The analysis of the track of no turning non-motorized vehicles when avoiding the vehicles turning right

    Institute of Scientific and Technical Information of China (English)

    潘晓东; 陈丽烨

    2011-01-01

    Based on the observing experiment in which videos are taped at the cross roads, analysis on the unsafe behavior of riders and the conflicts between no turning non-motorized vehicles and vehicles turning right, as well as the avoiding track, are done. Different factors, such as the riders' sex, age or the type of the vehicles, are considered depending on the degree in which they influence the type of the avoiding track. At the same time, the result confirms the danger exists in the conflicts between non-motorized vehicles and large-sized vehicles turning right. Some solutions to improve traffic safety are mentioned at the end.%通过交叉口拍摄视频的观察实验,对非机动车不安全行为进行了分析,对交叉口的直行非机动车与右转机动车之间的冲突现象进行了观察,对冲突发生时非机动车避让机动车的轨迹进行了分析.并从骑行者性别、年龄和车辆类型等角度人手,分析了不同因素对避让轨迹选择的影响,同时,验证了直行非机动车与右转大型车辆冲突时存在的安全隐患.最后,从机动车和非机动车骑行者两个角度出发,提出了相应的管理改善措施.

  15. Analysis of an off road 4WD vehicle's suspension system modification - Case study of aftermarket suspension lift and modification of wheel track size

    Science.gov (United States)

    Ross, J.; Hazrat, M. A.; Rasul, M. G.

    2016-07-01

    In this research, a four wheel drive (4WD) suspension of a vehicle has been modified by increasing the ride height to investigate stability and cornering potential of the vehicle through load transfer and variation of roll angle. Further investigation has been conducted to observe the characteristics which are deemed desirable for off road application but detrimental to the on road application. The Constant Radius Cornering Test (CRCT) was chosen as a base method for experimental investigation to observe the effect of the suspension modifications. The test was carried out by undertaking a known radius and cambered corner at a constant speed. For this test, the acceleration and gyroscopic data were measured to check and compare the accuracy of the analysis performed by OptimumDynamics model. The tests were conducted by means of negotiating the curve at the speed of 80 km/h and it was gradually achieved to allow a good consensus of the amount of body roll the vehicle experienced. Using a surveyor's wheel, the radius of the corner was estimated as 160 m and using the gyroscopic sensor, the corner camber was measured at 4 degrees. While comparing the experimental results with the simulation results, the experimental constraints led to higher values than those of the analytical results. The total load transfer reduced by 2.9% with the increased track size. It has been observed that the dynamic load transfer component is lesser than the standard suspension with the aftermarket suspension lift and the upgraded anti-roll bar (ARB). With the simulation of the fitment of the other modifications aimed to improve the characteristics of the raised vehicle, the vehicle showed a reduced tendency towards roll angle due to the stiffened anti-roll bar and the maximum increased wheel track demonstrated reduced lateral load transfer and body roll. Even with these modifications however, the decrease in load transfer is minimal in comparison to what was expected.

  16. Leader-Follower Tracking System for Agricultural Vehicles: Fusion of Laser and Odometry Positioning Using Extended Kalman Filter

    Directory of Open Access Journals (Sweden)

    Zhang Lin Huan

    2015-03-01

    Full Text Available The aim of this research was to develop a safe human-driven and autonomous leader-follower tracking system for an autonomous tractor. To enable the tracking system, a laser range finder (LRF-based landmark detection system was designed to observe the relative position between a leader and a follower used in agricultural operations. The virtual follower-based formation-tracking algorithm was developed to minimize tracking errors and ensure safety. An extended Kalman filter (EKF was implemented for fusing LRF and odometry position to ensure stability of tracking in noisy farmland conditions. Simulations were conducted for tracking the leader in small and large sinusoidal curved paths. Simulated results verified high accuracy of formation tracking, stable velocity, and regulated steering angle of the follower. The tracking method confirmed the follower could follow the leader with a required formation safely and steadily in noisy conditions. The EKF helped to improve observation accuracy, velocity, and steering angle stability of the follower. As a result of the improved accuracy of observation and motion action, the tracking performance for lateral, longitudinal, and heading were also improved after the EKF was implemented in the tracking system.

  17. Modeling and Simulation of Commercial Vehicle Fuel Economy Based on Vehicle Speed Tracking%基于车速跟踪的商用车燃油经济性建模与仿真

    Institute of Scientific and Technical Information of China (English)

    李刚炎; 史慧平; 涂鸣; 胡剑; 牛子孺

    2015-01-01

    针对燃油经济性仿真模型仅能计算车辆在模态工况下的燃油消耗量的问题,提出了一种基于车速跟踪的燃油经济性仿真模型的建模方法。在建立车辆纵向动力学模型、驾驶意图模型和发动机与传动系统模型的基础上,利用 MATLAB/Simulink 搭建了商用车燃油经济性仿真模型,并以某客车为例进行了试验与仿真对比。对比结果表明:所建模型能对商用车的任意行驶工况进行较好的车速跟踪,并能对商用车在该行驶工况下的燃油消耗量进行较为准确的仿真计算。通过更改仿真模型中的相关车辆参数,可以方便快速地进行不同动力总成配置的商用车的燃油经济性仿真计算。%Most of the fuel economy simulation models can only calculate fuel consumption of the vehicle in modal cycles.To solve the problem,a new method for commercial vehicle fuel economy mod-eling method was proposed based on longitudinal vehicle speed tracking.On the premise of the estab-lishment of vehicle longitudinal dynamics model,driving intention model,engine and transmission sys-tem model,a commercial vehicle fuel economy simulation model was built with MATLAB/Simulink. Taking a bus as an example,a comparison was made between vehicle test and model simulation,the re-sults of which show that:the simulation model can follow any driving cycle of commercial vehicle very well,and calculate the commercial vehicle fuel consumption in the driving cycle accurately.By changing the vehicle related parameters in the simulation model,simulation of fuel economy for commercial ve-hicles with various powertrain configuration can be carried out conveniently and quickly.

  18. Multi-spectral band selection for satellite-based systems

    Energy Technology Data Exchange (ETDEWEB)

    Clodius, W.B.; Weber, P.G.; Borel, C.C.; Smith, B.W.

    1998-09-01

    The design of satellite based multispectral imaging systems requires the consideration of a number of tradeoffs between cost and performance. The authors have recently been involved in the design and evaluation of a satellite based multispectral sensor operating from the visible through the long wavelength IR. The criteria that led to some of the proposed designs and the modeling used to evaluate and fine tune the designs will both be discussed. These criteria emphasized the use of bands for surface temperature retrieval and the correction of atmospheric effects. The impact of cost estimate changes on the final design will also be discussed.

  19. Research on Path Tracking Control of Autonomous Vehicle%无人驾驶车路径跟踪控制研究

    Institute of Scientific and Technical Information of China (English)

    修彩靖; 陈慧

    2012-01-01

    研究被控对象无人驾驶车,基于预瞄控制思想,设计一种无人驾驶车路径跟踪控制器,将控制器分为预瞄控制和补偿控制两部分,预瞄控制模拟驾驶员在驾驶车辆过程中对前方的道路环境信息进行预瞄,根据道路曲率程度决定方向盘转向,补偿控制是对车辆遇到干扰偏离原车道的纠正.仿真实验结果表明,该控制器能够保证无人驾驶车准确跟踪各种参考路径,且具有较好的鲁棒性.%This paper designs path tracking controller based on preview control thought for autonomous vehicle that is non-linear controlled object. Controller includes two parts, preview control and compensation control, preview control previews ahead road by simulation for the process of driving, and generates control signal of steering angle according to the curvature of road, while the compensation control is the amendment for the interference encountered in the vehicle lane deviation from the original correction. Simulation experimental results show that the proposed control algorithm can ensure tracking reference path of autonomous vehicles accurately, and has good robustness.

  20. A Real-Time Method to Detect and Track Moving Objects (DATMO from Unmanned Aerial Vehicles (UAVs Using a Single Camera

    Directory of Open Access Journals (Sweden)

    Bruce MacDonald

    2012-04-01

    Full Text Available We develop a real-time method to detect and track moving objects (DATMO from unmanned aerial vehicles (UAVs using a single camera. To address the challenging characteristics of these vehicles, such as continuous unrestricted pose variation and low-frequency vibrations, new approaches must be developed. The main concept proposed in this work is to create an artificial optical flow field by estimating the camera motion between two subsequent video frames. The core of the methodology consists of comparing this artificial flow with the real optical flow directly calculated from the video feed. The motion of the UAV between frames is estimated with available parallel tracking and mapping techniques that identify good static features in the images and follow them between frames. By comparing the two optical flows, a list of dynamic pixels is obtained and then grouped into dynamic objects. Tracking these dynamic objects through time and space provides a filtering procedure to eliminate spurious events and misdetections. The algorithms have been tested with a quadrotor platform using a commercial camera.

  1. Vehicle traveling track split of track-oriented survey and analysis in urban network%城市路网车辆出行轨迹获取的混合轨迹拆分

    Institute of Scientific and Technical Information of China (English)

    王龙飞; 陈红; 李杨; 邓亚娟

    2013-01-01

    针对采用车牌照进行车辆出行轨迹的调查分析过程中产生的混合轨迹问题,从分析原理、构建解集、拆分决策三方面研究了混合轨迹的拆分方法。建立了一次可达网络模型,阐明了面向轨迹交通调查的工作机理,通过对比分析正常轨迹和混合轨迹特征,采用基于栈式节点存储的深度优先搜索算法构建了车辆出行轨迹拆分解集。在此基础上,考虑时距相符程度、路径模式匹配程度、路径曲折度指标建立轨迹效用函数,利用TOPSIS法进行轨迹拆分的最优解决策,通过算例说明了算法的有效性。%In order to solve mixed track problem in the process of survey and analysis for vehicle track based on plate number, a method of track split is studied by principle analysis, constructing solution set and split decision. A Direct Access Network model (DAN)is established to describe the accessibility relation among survey points, and then the working mechanism based on DAR for track-oriented traffic survey is illustrated. Through the comparative analysis of features of normal track and mixed track, the in-depth priority search algorithm is applied to constructing the solution set of split tracks. According to the correspondence degree between distance and time, matching degree of route patterns and tortuous degree of route, the track utility function is constructed and the optimal decision-making of split track is made using TOPSIS method. An example is given to illustrate the effectiveness of the method.

  2. Validation of an Innovative Satellite-Based UV Dosimeter

    Science.gov (United States)

    Morelli, Marco; Masini, Andrea; Simeone, Emilio; Khazova, Marina

    2016-08-01

    We present an innovative satellite-based UV (ultraviolet) radiation dosimeter with a mobile app interface that has been validated by exploiting both ground-based measurements and an in-vivo assessment of the erythemal effects on some volunteers having a controlled exposure to solar radiation.Both validations showed that the satellite-based UV dosimeter has a good accuracy and reliability needed for health-related applications.The app with this satellite-based UV dosimeter also includes other related functionalities such as the provision of safe sun exposure time updated in real-time and end exposure visual/sound alert. This app will be launched on the global market by siHealth Ltd in May 2016 under the name of "HappySun" and available both for Android and for iOS devices (more info on http://www.happysun.co.uk).Extensive R&D activities are on-going for further improvement of the satellite-based UV dosimeter's accuracy.

  3. Satellite based wind resource assessment over the South China Sea

    DEFF Research Database (Denmark)

    Badger, Merete; Astrup, Poul; Hasager, Charlotte Bay

    2014-01-01

    modeling to develop procedures and best practices for satellite based wind resource assessment offshore. All existing satellite images from the Envisat Advanced SAR sensor by the European Space Agency (2002-12) have been collected over a domain in the South China Sea. Wind speed is first retrieved from...

  4. The Seismic Response of High-Speed Railway Bridges Subjected to Near-Fault Forward Directivity Ground Motions Using a Vehicle-Track-Bridge Element

    Directory of Open Access Journals (Sweden)

    Chen Ling-kun

    2014-01-01

    Full Text Available Based on the Next Generation Attenuation (NGA project ground motion library, the finite element model of the high-speed railway vehicle-bridge system is established. The model was specifically developed for such system that is subjected to near-fault ground motions. In addition, it accounted for the influence of the rail irregularities. The vehicle-track-bridge (VTB element is presented to simulate the interaction between train and bridge, in which a train can be modeled as a series of sprung masses concentrated at the axle positions. For the short period railway bridge, the results from the case study demonstrate that directivity pulse effect tends to increase the seismic responses of the bridge compared with far-fault ground motions or nonpulse-like motions and the directivity pulse effect and high values of the vertical acceleration component can notably influence the hysteretic behaviour of piers.

  5. Satellite-based assessment of yield variation and its determinants in smallholder African systems

    Science.gov (United States)

    Lobell, David B.

    2017-01-01

    The emergence of satellite sensors that can routinely observe millions of individual smallholder farms raises possibilities for monitoring and understanding agricultural productivity in many regions of the world. Here we demonstrate the potential to track smallholder maize yield variation in western Kenya, using a combination of 1-m Terra Bella imagery and intensive field sampling on thousands of fields over 2 y. We find that agreement between satellite-based and traditional field survey-based yield estimates depends significantly on the quality of the field-based measures, with agreement highest (R2 up to 0.4) when using precise field measures of plot area and when using larger fields for which rounding errors are smaller. We further show that satellite-based measures are able to detect positive yield responses to fertilizer and hybrid seed inputs and that the inferred responses are statistically indistinguishable from estimates based on survey-based yields. These results suggest that high-resolution satellite imagery can be used to make predictions of smallholder agricultural productivity that are roughly as accurate as the survey-based measures traditionally used in research and policy applications, and they indicate a substantial near-term potential to quickly generate useful datasets on productivity in smallholder systems, even with minimal or no field training data. Such datasets could rapidly accelerate learning about which interventions in smallholder systems have the most positive impact, thus enabling more rapid transformation of rural livelihoods. PMID:28202728

  6. Study on stability and controllability of high-speed tracked vehicles. ; Linear model and response characteristic. Kosoku soki sharyo no sosa anteisei ni tsuite. ; Senkei model to oto tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Kitano, M.; Watanabe, K.; Nagatomo, N. (National Defence Academy, Kanagawa, (Japan))

    1990-04-01

    The study on the steerability and stability of tracked vehicles is carried out by a linear equation of motion. In order to comprehend systematically the characteristic of motion of tracked vehicles, a linear equation of motion was developed from the conventional non-linear equation. With clarifying the applicable linear range, the validity of the linear model was confirmed by numerical results of the non-linear model and experimental results by using a scale model. It became clear that the motion of tracked vehicles was comprehended through this linear model, and that the motion was stable under some range of vehicle-speed and steering-ratio, because the response of the motion was damped without oscillation. In addition, it became clear through the simulation of transient and frequency responses that for improvement of the dynamics of a high-speed tracked vehicle, increase of the friction coefficient between the track and ground or appropriate selection of steering frequency was very important. 5 refs., 12 figs., 1 tab.

  7. Global trends in satellite-based emergency mapping.

    Science.gov (United States)

    Voigt, Stefan; Giulio-Tonolo, Fabio; Lyons, Josh; Kučera, Jan; Jones, Brenda; Schneiderhan, Tobias; Platzeck, Gabriel; Kaku, Kazuya; Hazarika, Manzul Kumar; Czaran, Lorant; Li, Suju; Pedersen, Wendi; James, Godstime Kadiri; Proy, Catherine; Muthike, Denis Macharia; Bequignon, Jerome; Guha-Sapir, Debarati

    2016-07-15

    Over the past 15 years, scientists and disaster responders have increasingly used satellite-based Earth observations for global rapid assessment of disaster situations. We review global trends in satellite rapid response and emergency mapping from 2000 to 2014, analyzing more than 1000 incidents in which satellite monitoring was used for assessing major disaster situations. We provide a synthesis of spatial patterns and temporal trends in global satellite emergency mapping efforts and show that satellite-based emergency mapping is most intensively deployed in Asia and Europe and follows well the geographic, physical, and temporal distributions of global natural disasters. We present an outlook on the future use of Earth observation technology for disaster response and mitigation by putting past and current developments into context and perspective.

  8. Global trends in satellite-based emergency mapping

    Science.gov (United States)

    Voigt, Stefan; Giulio-Tonolo, Fabio; Lyons, Josh; Kučera, Jan; Jones, Brenda; Schneiderhan, Tobias; Platzeck, Gabriel; Kaku, Kazuya; Hazarika, Manzul Kumar; Czaran, Lorant; Li, Suju; Pedersen, Wendi; James, Godstime Kadiri; Proy, Catherine; Muthike, Denis Macharia; Bequignon, Jerome; Guha-Sapir, Debarati

    2016-01-01

    Over the past 15 years, scientists and disaster responders have increasingly used satellite-based Earth observations for global rapid assessment of disaster situations. We review global trends in satellite rapid response and emergency mapping from 2000 to 2014, analyzing more than 1000 incidents in which satellite monitoring was used for assessing major disaster situations. We provide a synthesis of spatial patterns and temporal trends in global satellite emergency mapping efforts and show that satellite-based emergency mapping is most intensively deployed in Asia and Europe and follows well the geographic, physical, and temporal distributions of global natural disasters. We present an outlook on the future use of Earth observation technology for disaster response and mitigation by putting past and current developments into context and perspective.

  9. Global trends in satellite-based emergency mapping

    Science.gov (United States)

    Voigt, Stefan; Giulio-Tonolo, Fabio; Lyons, Josh; Kučera, Jan; Jones, Brenda; Schneiderhan, Tobias; Platzeck, Gabriel; Kaku, Kazuya; Hazarika, Manzul Kumar; Czaran, Lorant; Li, Suju; Pedersen, Wendi; James, Godstime Kadiri; Proy, Catherine; Muthike, Denis Macharia; Bequignon, Jerome; Guha-Sapir, Debarati

    2016-07-01

    Over the past 15 years, scientists and disaster responders have increasingly used satellite-based Earth observations for global rapid assessment of disaster situations. We review global trends in satellite rapid response and emergency mapping from 2000 to 2014, analyzing more than 1000 incidents in which satellite monitoring was used for assessing major disaster situations. We provide a synthesis of spatial patterns and temporal trends in global satellite emergency mapping efforts and show that satellite-based emergency mapping is most intensively deployed in Asia and Europe and follows well the geographic, physical, and temporal distributions of global natural disasters. We present an outlook on the future use of Earth observation technology for disaster response and mitigation by putting past and current developments into context and perspective.

  10. Trellis-coded CPM for satellite-based mobile communications

    Science.gov (United States)

    Abrishamkar, Farrokh; Biglieri, Ezio

    1988-01-01

    Digital transmission for satellite-based land mobile communications is discussed. To satisfy the power and bandwidth limitations imposed on such systems, a combination of trellis coding and continuous-phase modulated signals are considered. Some schemes based on this idea are presented, and their performance is analyzed by computer simulation. The results obtained show that a scheme based on directional detection and Viterbi decoding appears promising for practical applications.

  11. A nonlinear and fractional derivative viscoelastic model for rail pads in the dynamic analysis of coupled vehicle-slab track systems

    Science.gov (United States)

    Zhu, Shengyang; Cai, Chengbiao; Spanos, Pol D.

    2015-01-01

    A nonlinear and fractional derivative viscoelastic (FDV) model is used to capture the complex behavior of rail pads. It is implemented into the dynamic analysis of coupled vehicle-slab track (CVST) systems. The vehicle is treated as a multi-body system with 10 degrees of freedom, and the slab track is represented by a three layer Bernoulli-Euler beam model. The model for the rail pads is one dimensional, and the force-displacement relation is based on a superposition of elastic, friction, and FDV forces. This model takes into account the influences of the excitation frequency and of the displacement amplitude through a fractional derivative element, and a nonlinear friction element, respectively. The Grünwald representation of the fractional derivatives is employed to numerically solve the fractional and nonlinear equations of motion of the CVST system by means of an explicit integration algorithm. A dynamic analysis of the CVST system exposed to excitations of rail harmonic irregularities is carried out, pointing out the stiffness and damping dependence on the excitation frequency and the displacement amplitude. The analysis indicates that the dynamic stiffness and damping of the rail pads increase with the excitation frequency while they decrease with the displacement amplitude. Furthermore, comparisons between the proposed model and ordinary Kelvin model adopted for the CVST system, under excitations of welded rail joint irregularities and of random track irregularities, are conducted in the time domain as well as in the frequency domain. The proposed model is shown to possess several modeling advantages over the ordinary Kelvin element which overestimates both the stiffness and damping features at high frequencies.

  12. Dynamic simulation analysis for emergent braking of a tracked vehicle%履带车辆紧急制动动力学仿真分析

    Institute of Scientific and Technical Information of China (English)

    李伟; 马吉胜; 李志强; 范兆军

    2009-01-01

    基于虚拟样机技术,用ADAMS/ATV模块建立了某型履带车辆的紧急制动动力学模型.通过实车的行驶试验和紧急制动试验对模型进行了VV&A验证,结果表明所建动力学模型在反映履带车辆行驶及紧急制动动力学行为方面能够满足工程分析的需要.将其作为分析平台,对履带车辆进行了紧急制动动力学仿真分析,分析了3-6档平均车速下紧急制动的动力学响应;并通过紧急制动仿真实验得到了履带车辆的制动特性图.%Based on virtual prototyping technology, the dynamic model for emergent braking of a certain tracked ve- hicle was established by means of ADAMS/ATV software. With travel test and emergent braking test of a tracked vehicle, VV&A of the dynamic model was carried out and its credence was proved. Using it as a simulation base, the dynamic sim- ulation analysis for emergent braking of the tracked vehicle was carried out. The emergent braking dynamic responses at the mean velocity of 3-6 gear ranks were analyzed and the braking characteristic curve was obtained with a simulation test of emergent braking.

  13. Reduction of lateral forces between the railway vehicle and the track in small-radius curves by means of active elements

    Directory of Open Access Journals (Sweden)

    Michálek T.

    2011-12-01

    Full Text Available This paper deals with a possibility of reduction of guiding forces magnitude in small-radius curves by means of active elements. These guiding forces characterize the lateral force interaction between the rail vehicle and the track and influence the wear of wheels and rails in curves. Their magnitudes are assessed in the framework of vehicle authorization process. However, in case of new railway vehicles with axleload of approximately 20t and more it is problematic to meet the condition of maximum value of the quasistatic guiding force which acts on the outer wheel of the 1st wheelset in small-radius curves. One of the possible ways how to reduce these forces is using the system of active yaw dampers. By means of computer simulations of guiding behaviour of a new electric locomotive, comparison of reached values of the quasistatic guiding forces in case of locomotive equipped with active yaw dampers and without them was performed. Influences of magnitude of force generated by the active yaw dampers, friction coefficient in wheel/rail contact and curve radius were analysed in this work, as well.

  14. On-Track Testing as a Validation Method of Computational Fluid Dynamic Simulations of a Formula SAE Vehicle

    Science.gov (United States)

    Weingart, Robert

    This thesis is about the validation of a computational fluid dynamics simulation of a ground vehicle by means of a low-budget coast-down test. The vehicle is built to the standards of the 2014 Formula SAE rules. It is equipped with large wings in the front and rear of the car; the vertical loads on the tires are measured by specifically calibrated shock potentiometers. The coast-down test was performed on a runway of a local airport and is used to determine vehicle specific coefficients such as drag, downforce, aerodynamic balance, and rolling resistance for different aerodynamic setups. The test results are then compared to the respective simulated results. The drag deviates about 5% from the simulated to the measured results. The downforce numbers show a deviation up to 18% respectively. Moreover, a sensitivity analysis of inlet velocities, ride heights, and pitch angles was performed with the help of the computational simulation.

  15. Visual feedback navigation for cable tracking by autonomous underwater vehicles; Jiritsugata kaichu robot no gazo shori ni motozuku cable jido tsuiju

    Energy Technology Data Exchange (ETDEWEB)

    Takai, M.; Ura, T. [The University of Tokyo, Tokyo (Japan). Institute of Industrial Science; Balasuriya, B.; Lam, W. [The University of Tokyo, Tokyo (Japan); Kuroda, Y. [Meiji Univ., Tokyo (Japan)

    1997-08-01

    A vision processing unit was introduced into autonomous underwater vehicles (AUV) to judge the visual situation and to construct an environmental observation platform that can collect wide-range and high-precision measurement data. The cable optionally installed at the bottom of the sea was recognized by vision processing to propose automatic tracking technique. An estimator that compensates for the hough conversion or time delay and a PSA controller that is used as a target value set mechanism or lower-level controller were introduced as the factor technology required for automatic tracking. The feature of the automatic tracking is that a general-purpose platform which can observe the prescribed range environmentally in high precision and density can be constructed because the observation range required by the observer can be prescribed near the sea-bottom surface using a cable. The verification result off Omi Hachiman at Lake Biwa showed that AUV can be used for the high-precision environmental survey in the range prescribed near the sea-bottom surface using a cable. 8 refs., 8 figs., 1 tab.

  16. 四旋翼飞行器建模及位置跟踪控制%Modelling and position tracking control for quadrotor vehicle

    Institute of Scientific and Technical Information of China (English)

    王红雨; 赵健康; 郁文贤; 田蔚风

    2012-01-01

    相对其他无人飞行器平台,四旋翼飞行器有其独特的优势,因而受到广泛的关注.位置跟踪控制对四旋翼飞行器的应用非常重要.在阐述四旋翼飞行器的飞行原理和操控机制的基础上,研究了其动力学模型,并提出了一种简化的数学模型.四旋翼飞行器是欠驱动耦合系统,为了实现系统解耦并得到清晰的控制回路,设计了多回路PID控制方案,其控制目标是位置和偏航角,而姿态角和横滚角由位置误差调节.最后,通过仿真验证了控制方法的有效性.%Quadrotor vehicles have attracted more and more interests for their distinct advantages over other unmanned air vehicles(UAVs).Position tracking control is very important for the application of the quadrotor vehicle.In this paper,the flight theory and manipulative mechanism of the quadrotor vehicle were described.The dynamic model was studied,and a simplified mathematical model was obtained.The quadrotor is a coupled under-actuated rotorcraft.In order to decouple the dynamic system and achieve clear control loops,a multi-loop PID control scheme was employed.The control goal is to make the position and yaw angle stabilized at the reference values,while the pitch and roll angles were regulated by the position errors.At last,a simulation was carried out which verified the effectiveness of the control strategy.

  17. 机车车辆轨道扭曲抗脱轨能力评价%Resistance of Railway Vehicles to Derailment on Twisted Track

    Institute of Scientific and Technical Information of China (English)

    丁雪萍; 罗赟

    2012-01-01

    Method of measuring the safety against derailment by running through a twisted test track in AS 7509.1"Railway Rolling Stock-Dynamic Behavior-Part 1: Locomotive Rolling Stock", which published in 2009 in Australia, was briefly introduced in this thesis. The safety against derailment was calculated based on the standard testing track condition in AS 7509.1 reappeared in the SIMPACK software. Compared with methods of computer simulation of vehicle resistance to flange climbing derailment at low speed in BS EN 14363 "Railway applications-Testing for the acceptance of running characteristics of railway vehicles -Testing of running behavior and stationary tests" published in 2005 in Europe, the AS 7509.1 standard is more reliable and applicable in the evaluation methods of railway vehicle resistance to derailment on twisted track.%介绍了澳大利亚于2009年颁布的AS 7509.1《铁路机车车辆—动力学性能—第1部分:机车车辆》中机车车辆在扭曲测试轨上脱轨安全性测量方法,在SIMPACK软件中模拟AS 7509.1标准中的实验扭曲轨道条件,进行车辆脱轨安全性计算方法.与欧洲在2005年颁布的BS EN 14363《铁路设施—铁路车辆运行特性的验收试验—运行性能试验和稳定性试验》中计算机仿真评价机车车辆低速抗爬轨能力方法进行比较分析得出,AS 7509.1标准比BS EN 14363标准验证车辆适应轨道扭曲能力的计算方法更可靠,适用性更广.

  18. Aggregated GPS tracking of vehicles and its use as a proxy of traffic-related air pollution emissions

    Science.gov (United States)

    Chen, Shimon; Bekhor, Shlomo; Yuval; Broday, David M.

    2016-10-01

    Most air quality models use traffic-related variables as an input. Previous studies estimated nearby vehicular activity through sporadic traffic counts or via traffic assignment models. Both methods have previously produced poor or no data for nights, weekends and holidays. Emerging technologies allow the estimation of traffic through passive monitoring of location-aware devices. Examples of such devices are GPS transceivers installed in vehicles. In this work, we studied traffic volumes that were derived from such data. Additionally, we used these data for estimating ambient nitrogen dioxide concentrations, using a non-linear optimisation model that includes basic dispersion properties. The GPS-derived data show great potential for use as a proxy for pollutant emissions from motor-vehicles.

  19. The Apache Longbow-Hellfire Missile Test at Yuma Proving Ground: Ecological Risk Assessment for Tracked Vehicle Movement across Desert Pavement

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Mark J [ORNL; Efroymson, Rebecca Ann [ORNL; Hargrove, William Walter [ORNL

    2008-01-01

    A multiple stressor risk assessment was conducted at Yuma Proving Ground, Arizona, as a demonstration of the Military Ecological Risk Assessment Framework. The focus was a testing program at Cibola Range, which involved an Apache Longbow helicopter firing Hellfire missiles at moving targets, M60-A1 tanks. This paper describes the ecological risk assessment for the tracked vehicle movement component of the testing program. The principal stressor associated with tracked vehicle movement was soil disturbance, and a resulting, secondary stressor was hydrological change. Water loss to washes and wash vegetation was expected to result from increased infiltration and/or evaporation associated with disturbances to desert pavement. The simulated exposure of wash vegetation to water loss was quantified using estimates of exposed land area from a digital ortho quarter quad aerial photo and field observations, a 30 30 m digital elevation model, the flow accumulation feature of ESRI ArcInfo, and a two-step process in which runoff was estimated from direct precipitation to a land area and from water that flowed from upgradient to a land area. In all simulated scenarios, absolute water loss decreased with distance from the disturbance, downgradient in the washes; however, percentage water loss was greatest in land areas immediately downgradient of a disturbance. Potential effects on growth and survival of wash trees were quantified by using an empirical relationship derived from a local unpublished study of water infiltration rates. The risk characterization concluded that neither risk to wash vegetation growth or survival nor risk to mule deer abundance and reproduction was expected. The risk characterization was negative for both the incremental risk of the test program and the combination of the test and pretest disturbances.

  20. A computer model for evaluation of launch vehicle and target tracking error assignments for direct ascent, deep space ASAT (Anti-satellite) systems

    Science.gov (United States)

    Barclay, R. C.

    1983-12-01

    An unclassified computer model was developed for first order evaluation of deep space Anti-satellite (ASAT) targeting error assignments. Two independent error sources are modeled. With deep space tracking accuracies on the order of kilometers, there is uncertainty in the exact target position. Errors introduced by the launch vehicle guidance system result in uncertainty in the exact position of the ASAT itself. Once the target is acquired by the ASAT sensor subsystem, the maneuver subsystem must then have the capability to make the necessary trajectory corrections to precent a miss. The model assumes a direct ascent vehicle for which the user selects a trajectory by choosing the burnout and intercept position vectors, and a time of flight between them. Monte Carlo simulation is used to generate errors in burnout position and velocity, and intercept position from trivariate normal distributions scaled to user input standard deviations. This is repeated for 500 iterations, from which a mean miss distance and delta V required for trajectory correction can be determined, and used for further analysis.

  1. Tracked Vehicle - Soft Soil Interactions and Design Sensitivities for Path Clearing Systems Utilizing Multi-Body Dynamics Simulation Methods

    Science.gov (United States)

    2013-08-13

    radius – Pot hole: 17 cm deep x 60 cm long – V-ditch: 1.4 m deep x 7.8 m long – Grades: 40%-60% – Cross-country ( clay only) 13 August 2013 3...band track – Flail or roller-rake path clearing implement. • Soft soil mobility events conducted over clay and sand: – Half-round bump: 17.5 cm...Soil Property Sand Clay Exponent Number (n) [] 1.1 0.13 Terrain Stiffness (kC) [kN/m1+n] 0.99 12.7 Terrain

  2. Vehicle Tracking Based on Improved Deterministic Data Association%基于改进的确定性目标关联的车辆跟踪方法

    Institute of Scientific and Technical Information of China (English)

    周俊静; 段建民; 杨光祖

    2014-01-01

    现有的确定性目标关联方法采用全局优化确定目标和跟踪器间的关联,只能对确定数目的目标进行跟踪,不能直接应用于辅助驾驶系统的车辆检测。为将确定性目标关联方法引入到车辆检测系统中,文中提出局部优化的确定性目标关联方法,辅以合适的跟踪器管理策略,根据实际道路情况动态地增加和删除跟踪器,并实现对暂时遮挡或漏检的目标保持跟踪的连贯性。为提高关联的准确性,融合目标的多个特征定义代价方程,将运动特征作为代价方程的主要约束条件,同时考虑目标的外形特征。通过实验验证本文跟踪方法在车辆检测系统中的有效性。%The existing deterministic data association defines the optimal track set by global optimization algorithms, which can only work with prior knowledge of the objects number. Therefore, it is limited to vehicle detection in driver assistance system. A local optimization algorithm is proposed to implement deterministic correspondence in vehicle detection. With the aid of a proper tracker management strategy, the algorithm can handle object entries, object exits and occlusions. To improve the accuracy of correspondence, the cost function is defined by fusing multiple features. The motion feature and the figuration features are taken as main constraint condition and minor ones respectively. The validity of the tracking algorithm in vehicle detection system is verified by experiments.

  3. 履带车辆试验路面统计特性的仿真%Modeling Research on Road Used for Virtual Experiment of Tracked Vehicle

    Institute of Scientific and Technical Information of China (English)

    薛劲橹; 王红岩; 迟宝山

    2012-01-01

    3D stochastic road model for the virtual test of tracked vehicle is built by using Matlab programming, and the power spectral estimation on the toad roughness of single path and the verification on the correlation among different single paths are conducted. A universal algorithm for node creation of 3D road surface suitable for tracked vehicle module ATV in Adams software is created. The effects of mesh size on the accuracy of road surface model are analyzed for both 3D stochastic road and road with definite profile respectively. A virtual test of vehicle straight running on stochastic road is performed. The results show that the 3D and 2D stochastic roads give quite different results of virtual tests. 3D stochastic road can simulate the action of loads in both vertical and lateral directions so is superior to 2D stochastic road.%利用Matlab编程建立了用于履带车辆虚拟试验的三维随机路面模型,并对单道路面不平度进行了功率谱估计和不同单道相关性验证.创建了适用于Adams软件履带车辆模块(ATV)路面模型的三维路面节点生成通用算法.分别分析了三维随机路面和有确定外形路面网格数量对路面模型精度的影响.在随机路面上进行车辆直驶虚拟试验,结果表明,三维随机路面的虚拟试验结果与二维随机路面的有较大不同;三维随机路面可以模拟车辆垂向和侧向两个方向载荷的作用,优于二维随机路面.

  4. Crawling Feasibility Simulation Study on Tracked vehicle for Deep Ocean Mining%深海采矿履带式集矿机行走可行性仿真研究

    Institute of Scientific and Technical Information of China (English)

    王震宇; 刘少军; 李力

    2004-01-01

    履带式行走平台作为深海采矿集矿机子系统的工作平台行走在海底沉积物上进行深海采矿作业.分析了履带式行走平台简单数学模型,基于大型机械系统动力学分析软件履带车辆专用模块(ADAMS/ATV),构建了深海履带式集矿机多刚体系统模型.通过分析软件仿真了履带式集矿机虚拟样机在四种典型海泥路面上行走的过程,分析了仿真实验结果,履带式集矿机的深海行驶性能被证明比较满意.这种软泥上行走履带式车辆的建模和仿真研究方法被证明是一种有效的新方法.%Tracked vehicle platform as the operation platform of the deep-sea mining collector subsystem crawls on the deep-sea sediment. The feasibility of its crawling on the deep-sea soft soil in Chinese deep-ocean mining area is discussed. A new modeling approach Adams Tracked vehicle (ATV) is used to construct the multi-body system model of the tracked vehicle, a special tracked vehicle crawling on the seabed for deep ocean mining. The dynamic analysis software ADAMS/Solver is used to analyze the simulation of the tracked vehicle crawling on the four kinds of virtual seabed terrains respectively, and the simulation results basically tally with the real experimental data. The motion performance of the tracked vehicle is proven to be satisfactory. The new modeling and simulating method is also proven to be an efficient way to modeling a tracked vehicle and to simulating its dynamical performances.

  5. Emergency Braking Dynamic Simulation Analysis of Tracked Vehicle on Downward Slope Road%履带车辆下长坡紧急制动动力学仿真分析

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Based on virtual prototyping technology, emergency braking dynamic model of a certain tracked vehicle was established by means of ADAMS/ATV software. By travel test and emergency braking test of the tracked vehicle, VV&A of the emergency braking dynamic model was carried out and its credence was proved. The results show that the model can meet the needs of engineering analysis on dynamics behavior of travel and emergency braking. Using it as a simulation base, emergency braking dynamic simulation analysis of the tracked vehicle was carried out about the tracked vehicle on different slope of the road with different braking condition. Through the results, it has an important reference value for studying dynamics behavior of the emergency braking of tracked vehicle on the slope road.%  基于虚拟样机技术,用ADAMS/ATV模块建立了某型履带车辆紧急制动的动力学模型。通过实车的行驶试验和紧急制动试验对模型进行了验证,结果表明所建动力学模型在反映履带车辆行驶及紧急制动动力学行为方面能够满足工程分析的需要。将其作为分析平台,对履带车辆进行了下不同坡度路面在不同制动工况下的紧急制动的动力学仿真分析,通过仿真结果,对研究履带车辆下长坡紧急制动的动力学行为具有很大的参考价值。

  6. Global neural dynamic surface tracking control of strict-feedback systems with application to hypersonic flight vehicle.

    Science.gov (United States)

    Xu, Bin; Yang, Chenguang; Pan, Yongping

    2015-10-01

    This paper studies both indirect and direct global neural control of strict-feedback systems in the presence of unknown dynamics, using the dynamic surface control (DSC) technique in a novel manner. A new switching mechanism is designed to combine an adaptive neural controller in the neural approximation domain, together with the robust controller that pulls the transient states back into the neural approximation domain from the outside. In comparison with the conventional control techniques, which could only achieve semiglobally uniformly ultimately bounded stability, the proposed control scheme guarantees all the signals in the closed-loop system are globally uniformly ultimately bounded, such that the conventional constraints on initial conditions of the neural control system can be relaxed. The simulation studies of hypersonic flight vehicle (HFV) are performed to demonstrate the effectiveness of the proposed global neural DSC design.

  7. Satellite-Based EMI Detection, Identification, and Mitigation

    Science.gov (United States)

    Stottler, R.; Bowman, C.

    2016-09-01

    Commanding, controlling, and maintaining the health of satellites requires a clear operating spectrum for communications. Electro Magnetic Interference (EMI) from other satellites can interfere with these communications. Determining which satellite is at fault improves space situational awareness and can be used to avoid the problem in the future. The Rfi detection And Prediction Tool, Optimizing Resources (RAPTOR) monitors the satellite communication antenna signals to detect EMI (also called RFI for Radio Frequency Interference) using a neural network trained on past cases of both normal communications and EMI events. RAPTOR maintains a database of satellites that have violated the reserved spectrum in the past. When satellite-based EMI is detected, RAPTOR first checks this list to determine if any are angularly close to the satellite being communicated with. Additionally, RAPTOR checks the Space Catalog to see if any of its active satellites are angularly close. RAPTOR also consults on-line databases to determine if the described operating frequencies of the satellites match the detected EMI and recommends candidates to be added to the known offenders database, accordingly. Based on detected EMI and predicted orbits and frequencies, RAPTOR automatically reschedules satellite communications to avoid current and future satellite-based EMI. It also includes an intuitive display for a global network of satellite communications antennas and their statuses including the status of their EM spectrum. RAPTOR has been prototyped and tested with real data (amplitudes versus frequency over time) for both satellite communication signals and is currently undergoing full-scale development. This paper describes the RAPTOR technologies and results of testing.

  8. Locally-Delivered T-Cell-Derived Cellular Vehicles Efficiently Track and Deliver Adenovirus Delta24-RGD to Infiltrating Glioma

    Directory of Open Access Journals (Sweden)

    Rutger K. Balvers

    2014-08-01

    Full Text Available Oncolytic adenoviral vectors are a promising alternative for the treatment of glioblastoma. Recent publications have demonstrated the advantages of shielding viral particles within cellular vehicles (CVs, which can be targeted towards the tumor microenvironment. Here, we studied T-cells, often having a natural capacity to target tumors, for their feasibility as a CV to deliver the oncolytic adenovirus, Delta24-RGD, to glioblastoma. The Jurkat T-cell line was assessed in co-culture with the glioblastoma stem cell (GSC line, MGG8, for the optimal transfer conditions of Delta24-RGD in vitro. The effect of intraparenchymal and tail vein injections on intratumoral virus distribution and overall survival was addressed in an orthotopic glioma stem cell (GSC-based xenograft model. Jurkat T-cells were demonstrated to facilitate the amplification and transfer of Delta24-RGD onto GSCs. Delta24-RGD dosing and incubation time were found to influence the migratory ability of T-cells towards GSCs. Injection of Delta24-RGD-loaded T-cells into the brains of GSC-bearing mice led to migration towards the tumor and dispersion of the virus within the tumor core and infiltrative zones. This occurred after injection into the ipsilateral hemisphere, as well as into the non-tumor-bearing hemisphere. We found that T-cell-mediated delivery of Delta24-RGD led to the inhibition of tumor growth compared to non-treated controls, resulting in prolonged survival (p = 0.007. Systemic administration of virus-loaded T-cells resulted in intratumoral viral delivery, albeit at low levels. Based on these findings, we conclude that T-cell-based CVs are a feasible approach to local Delta24-RGD delivery in glioblastoma, although efficient systemic targeting requires further improvement.

  9. Simulation Research on Braking Performance of Tracked Vehicle Hydraulic Energy Storage Braking System%履带车辆液压储能式制动系统制动性能仿真研究

    Institute of Scientific and Technical Information of China (English)

    赵广俊; 吕建刚; 宋彬; 滕飞

    2011-01-01

    为了实现对履带车辆制动能量的回收利用,针对某型履带车辆建立其液压储能式制动系统,分析系统工作模式;在AMESim下建立液压储能式制动系统及车辆模型,在Matlab/Simulink下建立控制系统模型;提出基于踏板行程逻辑门限值的模糊控制策略;在驾驶员不同的制动意图和系统负荷能力条件下,对履带车辆的制动工况进行联合仿真研究.结果表明,在该控制策略下液压储能式制动系统实现了对履带车辆的稳定制动和对制动能量的有效回收.%In order to achieve the tracked vehicle braking energy recovery and utilization, a certain type of tracked vehicle hydraulic energy storage braking system was established, and the working mode was analyzed. The model of hydraulic energy storage braking system and the vehicle was established in AMESim, and the control system model was established in Matlab/Simulink. Fuzzy logic control strategy based on pedal opening threshold was proposed. Under the driver's different braking intention and conditions of system load capacity, the tracked vehicle's braking process was researched under co-simulation. The results show that with the control strategy in the hydraulic energy storage braking system, the stable braking of tracked vehicle and the effective recovery of braking energy were achieved.

  10. Path Tracking Control of High-speed 4WID-4WIS Autonomous Vehicle%高速4WID-4WIS自主车路径跟踪控制

    Institute of Scientific and Technical Information of China (English)

    阮久宏; 李贻斌; 杨福广; 荣学文

    2011-01-01

    高速4WID-4WIS自主车采用独立悬挂结构,所有车轮均可独市驱动、制动和转向.对自主车路径跟踪问题进行几何和运动学上的描述,结合Burckhardt非线性轮胎模型建立自主车作路径跟踪运动时的2阶动力学模型,提出自主车进行路径跟踪的协调控制体系结构,利用白抗扰控制方法设计路径跟踪系统纵向速度、侧向位移和横摆角运动3个动力学通道上的解耦控制器,使用非线性规划方法设计基于轮胎模型的控制分配求解器,并讨论了含系统参数误差的控制扰动问题.在大加速度条件下的双移线路径跟踪仿真结果表明,4WID-4WIS自主车能够快速、准确地跟踪路径,证明了本文路径跟踪控制方法的有效性.%Every wheel of the high-speed four-wheel-independent-drive & steering (4WID-4WIS) autonomous vehicle has its own independent suspension system, and can be driven, braked and steered independently.Firstly, the path tracking control problem of the autonomous vehicle is illustrated at geometry and kinematics levels, and combined with nonlinear Burckhardt tire model, the second-order dynamic models for autonomous vehicle's path tracking are built.Secondly, the path tracking coordinate control architecture of the autonomous vehicle is proposed.The decoupled controllers of the three kinematic channels, the longitudinal velocity, the lateral displacement and the yaw angle motion of the path tracking, are designed based on the active disturbance rejection control (ADRC) method.And the tire model based control allocation solver is subsequently designed by nonlinear programming.The parameter-error-induced control disturbance is then discussed.Lastly,the double-lane-changing path tracking simulations with big acceleration are done.The results show that the 4WID-4WIS autonomous vehicle can track the path rapidly and accurately, and the validity of the proposed path tracking control method is proved.

  11. Evaluating the hydrological consistency of satellite based water cycle components

    KAUST Repository

    Lopez Valencia, Oliver M.

    2016-06-15

    Advances in multi-satellite based observations of the earth system have provided the capacity to retrieve information across a wide-range of land surface hydrological components and provided an opportunity to characterize terrestrial processes from a completely new perspective. Given the spatial advantage that space-based observations offer, several regional-to-global scale products have been developed, offering insights into the multi-scale behaviour and variability of hydrological states and fluxes. However, one of the key challenges in the use of satellite-based products is characterizing the degree to which they provide realistic and representative estimates of the underlying retrieval: that is, how accurate are the hydrological components derived from satellite observations? The challenge is intrinsically linked to issues of scale, since the availability of high-quality in-situ data is limited, and even where it does exist, is generally not commensurate to the resolution of the satellite observation. Basin-scale studies have shown considerable variability in achieving water budget closure with any degree of accuracy using satellite estimates of the water cycle. In order to assess the suitability of this type of approach for evaluating hydrological observations, it makes sense to first test it over environments with restricted hydrological inputs, before applying it to more hydrological complex basins. Here we explore the concept of hydrological consistency, i.e. the physical considerations that the water budget impose on the hydrologic fluxes and states to be temporally and spatially linked, to evaluate the reproduction of a set of large-scale evaporation (E) products by using a combination of satellite rainfall (P) and Gravity Recovery and Climate Experiment (GRACE) observations of storage change, focusing on arid and semi-arid environments, where the hydrological flows can be more realistically described. Our results indicate no persistent hydrological

  12. Interoperability of satellite-based augmentation systems for aircraft navigation

    Science.gov (United States)

    Dai, Donghai

    The Federal Aviation Administration (FAA) is pioneering a transformation of the national airspace system from its present ground based navigation and landing systems to a satellite based system using the Global Positioning System (GPS). To meet the critical safety-of-life aviation positioning requirements, a Satellite-Based Augmentation System (SBAS), the Wide Area Augmentation System (WAAS), is being implemented to support navigation for all phases of flight, including Category I precision approach. The system is designed to be used as a primary means of navigation, capable of meeting the Required Navigation Performance (RNP), and therefore must satisfy the accuracy, integrity, continuity and availability requirements. In recent years there has been international acceptance of Global Navigation Satellite Systems (GNSS), spurring widespread growth in the independent development of SBASs. Besides the FAA's WAAS, the European Geostationary Navigation Overlay Service System (EGNOS) and the Japan Civil Aviation Bureau's MTSAT-Satellite Augmentation System (MSAS) are also being actively developed. Although all of these SBASs can operate as stand-alone, regional systems, there is increasing interest in linking these SBASs together to reduce costs while improving service coverage. This research investigated the coverage and availability improvements due to cooperative efforts among regional SBAS networks. The primary goal was to identify the optimal interoperation strategies in terms of performance, complexity and practicality. The core algorithms associated with the most promising concepts were developed and demonstrated. Experimental verification of the most promising concepts was conducted using data collected from a joint international test between the National Satellite Test Bed (NSTB) and the EGNOS System Test Bed (ESTB). This research clearly shows that a simple switch between SBASs made by the airborne equipment is the most effective choice for achieving the

  13. SAMIRA - SAtellite based Monitoring Initiative for Regional Air quality

    Science.gov (United States)

    Schneider, Philipp; Stebel, Kerstin; Ajtai, Nicolae; Diamandi, Andrei; Horalek, Jan; Nicolae, Doina; Stachlewska, Iwona; Zehner, Claus

    2016-04-01

    Here, we present a new ESA-funded project entitled Satellite based Monitoring Initiative for Regional Air quality (SAMIRA), which aims at improving regional and local air quality monitoring through synergetic use of data from present and upcoming satellites, traditionally used in situ air quality monitoring networks and output from chemical transport models. Through collaborative efforts in four countries, namely Romania, Poland, the Czech Republic and Norway, all with existing air quality problems, SAMIRA intends to support the involved institutions and associated users in their national monitoring and reporting mandates as well as to generate novel research in this area. Despite considerable improvements in the past decades, Europe is still far from achieving levels of air quality that do not pose unacceptable hazards to humans and the environment. Main concerns in Europe are exceedances of particulate matter (PM), ground-level ozone, benzo(a)pyrene (BaP) and nitrogen dioxide (NO2). While overall sulfur dioxide (SO2) emissions have decreased in recent years, regional concentrations can still be high in some areas. The objectives of SAMIRA are to improve algorithms for the retrieval of hourly aerosol optical depth (AOD) maps from SEVIRI, and to develop robust methods for deriving column- and near-surface PM maps for the study area by combining satellite AOD with information from regional models. The benefit to existing monitoring networks (in situ, models, satellite) by combining these datasets using data fusion methods will be tested for satellite-based NO2, SO2, and PM/AOD. Furthermore, SAMIRA will test and apply techniques for downscaling air quality-related EO products to a spatial resolution that is more in line with what is generally required for studying urban and regional scale air quality. This will be demonstrated for a set of study sites that include the capitals of the four countries and the highly polluted areas along the border of Poland and the

  14. PlumeSat: A Micro-Satellite Based Plume Imagery Collection Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ledebuhr, A.G.; Ng, L.C.

    2002-06-30

    This paper describes a technical approach to cost-effectively collect plume imagery of boosting targets using a novel micro-satellite based platform operating in low earth orbit (LEO). The plume collection Micro-satellite or PlueSat for short, will be capable of carrying an array of multi-spectral (UV through LWIR) passive and active (Imaging LADAR) sensors and maneuvering with a lateral divert propulsion system to different observation altitudes (100 to 300 km) and different closing geometries to achieve a range of aspect angles (15 to 60 degrees) in order to simulate a variety of boost phase intercept missions. The PlumeSat will be a cost effective platform to collect boost phase plume imagery from within 1 to 10 km ranges, resulting in 0.1 to 1 meter resolution imagery of a variety of potential target missiles with a goal of demonstrating reliable plume-to-hardbody handover algorithms for future boost phase intercept missions. Once deployed on orbit, the PlumeSat would perform a series phenomenology collection experiments until expends its on-board propellants. The baseline PlumeSat concept is sized to provide from 5 to 7 separate fly by data collects of boosting targets. The total number of data collects will depend on the orbital basing altitude and the accuracy in delivering the boosting target vehicle to the nominal PlumeSat fly-by volume.

  15. Fundamentals of Inertial Navigation, Satellite-based Positioning and their Integration

    CERN Document Server

    Noureldin, Aboelmagd; Georgy, Jacques

    2013-01-01

    Fundamentals of Inertial Navigation, Satellite-based Positioning and their Integration is an introduction to the field of Integrated Navigation Systems. It serves as an excellent reference for working engineers as well as textbook for beginners and students new to the area. The book is easy to read and understand with minimum background knowledge. The authors explain the derivations in great detail. The intermediate steps are thoroughly explained so that a beginner can easily follow the material. The book shows a step-by-step implementation of navigation algorithms and provides all the necessary details. It provides detailed illustrations for an easy comprehension. The book also demonstrates real field experiments and in-vehicle road test results with professional discussions and analysis. This work is unique in discussing the different INS/GPS integration schemes in an easy to understand and straightforward way. Those schemes include loosely vs tightly coupled, open loop vs closed loop, and many more.

  16. Development and validation of satellite based estimates of surface visibility

    Science.gov (United States)

    Brunner, J.; Pierce, R. B.; Lenzen, A.

    2015-10-01

    A satellite based surface visibility retrieval has been developed using Moderate Resolution Imaging Spectroradiometer (MODIS) measurements as a proxy for Advanced Baseline Imager (ABI) data from the next generation of Geostationary Operational Environmental Satellites (GOES-R). The retrieval uses a multiple linear regression approach to relate satellite aerosol optical depth, fog/low cloud probability and thickness retrievals, and meteorological variables from numerical weather prediction forecasts to National Weather Service Automated Surface Observing System (ASOS) surface visibility measurements. Validation using independent ASOS measurements shows that the GOES-R ABI surface visibility retrieval (V) has an overall success rate of 64.5% for classifying Clear (V ≥ 30 km), Moderate (10 km ≤ V skill during June through September, when Heidke skill scores are between 0.2 and 0.4. We demonstrate that the aerosol (clear sky) component of the GOES-R ABI visibility retrieval can be used to augment measurements from the United States Environmental Protection Agency (EPA) and National Park Service (NPS) Interagency Monitoring of Protected Visual Environments (IMPROVE) network, and provide useful information to the regional planning offices responsible for developing mitigation strategies required under the EPA's Regional Haze Rule, particularly during regional haze events associated with smoke from wildfires.

  17. Detection of Vehicle Tracks and Vegetation Damages Caused by use of Snowmobiles in the Longyearbyen Area on Svalbard using Unmanned Aircraft

    Science.gov (United States)

    Storvold, R.; Karlsen, S. R.; Solbø, S. A.; Johansen, B.; Johansen, K.; Høgda, K. A.; Tømmervik, H.; Zmarz, A.; Joly, D.

    2013-12-01

    The study area in the surroundings of Longyearbyen on Svalbard, Arctic Norway, located at 71.2°N and 16°E is characterized by dry Arctic climate with a snow season of more than eight months, annual precipitation of less than 200mm, and a mean July temperature of about 6°C. Longyearbyen is the main settlement on Svalbard, with about 2000 inhabitants. During the last two decades the number of snowmobiles have increased from a few hundred to a number almost equals the number of inhabitants, and snowmobile trips are today the one of the main leisure activities. In addition, thousands of tourist visits every spring, and many of these go on organized snowmobile trips. Due to the often thin snow cover, and use of snowmobile even during the spring snow melt in May and early June, the rapid growth in use of snowmobile has made some damage to the vegetation. Damage on the fragile vegetation caused by the skids and belts of the snowmobile can be observed in most parts of the Adventdalen valley, close to Longyearbyen. The main aim of this study is to explore the feasibility and accuracy of using data from Unmanned Aircraft Systems (UAS) to identify vehicle tracks and damages on vegetation caused by the use of snowmobiles. Use of UAS give the opportunity to carry out research in a manner that minimizes the environmental footprint of the research activities. Small unmanned aircraft, combining both fixed wing multi rotor types allow us to collect image data for vegetation mapping without having any personnel walking into the field disturbing the sensitive High Arctic ecosystems. UAS used here are inexpensive and simple to operate. They are being developed with the goal of providing airborne capabilities for scientists at an affordable cost. The aircraft were instrumented with a normal Canon Powershot S100 RGB compact camera and a modified Canon Powershot SX230 NDVI camera. The fixed wing aircraft was taking pictures from 100 meters altitude with ground resolution of 2.5 cm

  18. 钢弹簧浮置板轨道对车内噪声影响的实测与分析%Measurement and Analysis of Influence of Steel Spring Floating Slab Track on Vehicle Interior Noise

    Institute of Scientific and Technical Information of China (English)

    肖安鑫; 田野

    2012-01-01

    When a train passes through on steel spring floating slab, intermediate and low frequency noises will be generated in its vehicles. Such noises will reduce the traveling comfort. In this paper, the vehicle' s interior noises of floating slab in different tracks are compared and analyzed. The influence of steel spring floating slab track on vehicle' s interior noise is analyzed. The results show that the floating slab track with high damping steel spring can effectively reduce the interior noise.%在列车经过钢弹簧浮置板地段时,车内产生中低频噪声,影响着人们乘车环境舒适性.通过对不同钢弹簧浮置板轨道地段车内噪声的对比测试,分析钢弹簧浮置板轨道对车内噪声的影响,结果表明采用高阻尼钢弹簧浮置板轨道可有效降低车内噪声.

  19. Traffic Information Unit, Traffic Information System, Vehicle Management System, Vehicle, and Method of Controlling a Vehicle

    NARCIS (Netherlands)

    Papp, Z.; Doodeman, G.J.N.; Nelisse, M.W.; Sijs, J.; Theeuwes, J.A.C.; Driessen, B.J.F.

    2010-01-01

    A traffic information unit (MD1, MD2, MD3) according to the invention comprises a facility (MI) for tracking vehicle state information of individual vehicles present at a traffic infrastructure and a facility (T) for transmitting said vehicle state information to a vehicle (70B, 70E). A traffic

  20. Unmanned Aerial Vehicle (UAV) Dynamic-Tracking Directional Wireless Antennas for Low Powered Applications that Require Reliable Extended Range Operations in Time Critical Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Scott G. Bauer; Matthew O. Anderson; James R. Hanneman

    2005-10-01

    The proven value of DOD Unmanned Aerial Vehicles (UAVs) will ultimately transition to National and Homeland Security missions that require real-time aerial surveillance, situation awareness, force protection, and sensor placement. Public services first responders who routinely risk personal safety to assess and report a situation for emergency actions will likely be the first to benefit from these new unmanned technologies. ‘Packable’ or ‘Portable’ small class UAVs will be particularly useful to the first responder. They require the least amount of training, no fixed infrastructure, and are capable of being launched and recovered from the point of emergency. All UAVs require wireless communication technologies for real- time applications. Typically on a small UAV, a low bandwidth telemetry link is required for command and control (C2), and systems health monitoring. If the UAV is equipped with a real-time Electro-Optical or Infrared (EO/Ir) video camera payload, a dedicated high bandwidth analog/digital link is usually required for reliable high-resolution imagery. In most cases, both the wireless telemetry and real-time video links will be integrated into the UAV with unity gain omni-directional antennas. With limited on-board power and payload capacity, a small UAV will be limited with the amount of radio-frequency (RF) energy it transmits to the users. Therefore, ‘packable’ and ‘portable’ UAVs will have limited useful operational ranges for first responders. This paper will discuss the limitations of small UAV wireless communications. The discussion will present an approach of utilizing a dynamic ground based real-time tracking high gain directional antenna to provide extend range stand-off operation, potential RF channel reuse, and assured telemetry and data communications from low-powered UAV deployed wireless assets.

  1. 基于改进的EMD方法提取车辆-轨道垂向耦合系统动态特性%Dynamic characteristics extraction of vehicle-track vertically coupling system based on improved EMD

    Institute of Scientific and Technical Information of China (English)

    陈双喜; 林建辉; 陈建政

    2011-01-01

    In order to extract dynamic characteristics of vehicle-track coupling system, the method of improved empirical mode decomposition (IEMD) was presented. In the method, the field mean of extrema was adopted instead of the points envelope mean and the boundary wave matching algorithm was used to restrain the end effect. Based on the theory of vehicle-track coupling dynamics, the vehicle ballastless-track vertically coupling dynamics model was established. With the rail corrugation and rail irregularity excitation model, dynamic responses of vehicle-track coupling system were calculated at different driving speed. The dynamic responses were decomposed by IEMD, and then the intrinsic mode functions of vertical contact force, bogie acceleration, and car body acceleration were analyzed and compared. The results show: the IEMD can self-adaptively decompose vibration signals to intrinsic mode functions and so effectively extract dynamic characteristics of vehicle-track coupling system.%提出利用一种改进的经验模态分解(EMD)方法提取车辆-轨道耦合系统的动力学特性.该方法以改进的极值域均值代替极值点包络线的均值来提高局部均值的求解精度,以边界波形匹配预测法来抑制端点效应.基于车辆-轨道耦合动力学理论,建立客车-弹性支承块无砟轨道垂向耦合动力学模型,计算车辆-轨道耦合系统在波浪形磨损和轨道不平顺组合激励模型下的振动响应.运用改进的EMD方法对系统的振动响应进行经验模态分解,并且对轮轨力、转向架和车体加速度的本征函数进行分析和比较.研究结果表明:改进的EMD方法自适应地将振动响应分解成本征函数,能有效地提取车辆-轨道耦合系统的动力学特性.

  2. Satellite Based Extrusion Rates for the 2006 Augustine Eruption

    Science.gov (United States)

    Dehn, J.; Bailey, J. E.; Dean, K. G.; Skoog, R.; Valcic, L.

    2006-12-01

    include pyroclastic deposits or ashfall, which are included in the DEM subtraction approach. However the pyroclastics should only account for a small amount of the extruded volume. In spite of its limitations, satellite based extrusion modeling provides a reasonable and safe method to monitor volcanoes and detect change in eruption style in near real time.

  3. Groundwater Modelling For Recharge Estimation Using Satellite Based Evapotranspiration

    Science.gov (United States)

    Soheili, Mahmoud; (Tom) Rientjes, T. H. M.; (Christiaan) van der Tol, C.

    2017-04-01

    Groundwater movement is influenced by several factors and processes in the hydrological cycle, from which, recharge is of high relevance. Since the amount of aquifer extractable water directly relates to the recharge amount, estimation of recharge is a perquisite of groundwater resources management. Recharge is highly affected by water loss mechanisms the major of which is actual evapotranspiration (ETa). It is, therefore, essential to have detailed assessment of ETa impact on groundwater recharge. The objective of this study was to evaluate how recharge was affected when satellite-based evapotranspiration was used instead of in-situ based ETa in the Salland area, the Netherlands. The Methodology for Interactive Planning for Water Management (MIPWA) model setup which includes a groundwater model for the northern part of the Netherlands was used for recharge estimation. The Surface Energy Balance Algorithm for Land (SEBAL) based actual evapotranspiration maps from Waterschap Groot Salland were also used. Comparison of SEBAL based ETa estimates with in-situ abased estimates in the Netherlands showed that these SEBAL estimates were not reliable. As such results could not serve for calibrating root zone parameters in the CAPSIM model. The annual cumulative ETa map produced by the model showed that the maximum amount of evapotranspiration occurs in mixed forest areas in the northeast and a portion of central parts. Estimates ranged from 579 mm to a minimum of 0 mm in the highest elevated areas with woody vegetation in the southeast of the region. Variations in mean seasonal hydraulic head and groundwater level for each layer showed that the hydraulic gradient follows elevation in the Salland area from southeast (maximum) to northwest (minimum) of the region which depicts the groundwater flow direction. The mean seasonal water balance in CAPSIM part was evaluated to represent recharge estimation in the first layer. The highest recharge estimated flux was for autumn

  4. Analysis and Simulation on Dynamic Stress of Tracked Vehicle Sprocket%高速履带车辆主动轮动态应力仿真分析研究

    Institute of Scientific and Technical Information of China (English)

    田政; 陈兵; 尹忠俊; 王文瑞

    2011-01-01

    为研究高速履带车辆主动轮的动态应力强度优化问题,由于车辆在运动中承受交变载荷,主动轮受力较强.为改进结构强度,提出建立履带车辆多体动力学模型和车“履带板一主动轮”的单齿、多齿啮合模型以及刚柔耦合,对务工况设定进行了动态应力仿真.结果表明,履带车辆主动轮齿圈齿根处以及固定螺栓孔壁应力较大且在轮齿边缘部位存在应力集中.通过仿真,结果证明轮齿的受力不会对轮齿的应力产生影响,可为高速履带车辆行驶系统的结构设计及优化提供依据.%In order to research the dynamic stress of the tracked vehicle sprocket, this paper established a highspeed tracked vehicle dynamics model, in which the time loads of sprocket was simulated during the vehicle is running at 60km/h on the D class road. We established the " trackboard- sprocket" models of the single tooth in mesh and multiple teeth in mesh. The dynamic stress of the sprocket' s gear ring was acquired by analysis. Simulation results show that the stress of tracked vehicle sprocket' s gear root and the fixed gear bolt hole are larger, and the stress concentration is observed at the edge of the teeth. The other gear tooth' s forces only increase the stress of the fixed gear bolt hole compared with the results. The simulation results provide the calculation basis for the optimization of the high-speed tracked vehicle system.

  5. 改进强跟踪滤波算法及其在汽车状态估计中的应用%Improved Strong Track Filter and Its Application to Vehicle State Estimation

    Institute of Scientific and Technical Information of China (English)

    周聪; 肖建

    2012-01-01

    准确实时地获取汽车行驶过程中的状态变量,对汽车底盘控制有着重要的意义,而这些关键状态往往难以直接测量或者成本较高.结合纵向、侧向和横摆三自由度非线性汽车模型,将改进强跟踪滤波(Improved strong track filter,ISTF)算法应用到汽车的状态估计中,并改进了算法的稳定性.与扩展卡尔曼滤波(Extended Kalman filter,EKF)算法进行比较分析.通过Carsim和Matlab/Simulink联合仿真和实车双移线实验验证算法,结果表明,该算法在估计精度、跟踪速度、抑制噪声等方面均优于扩展卡尔曼滤波算法,满足汽车状态估计器的软件性能要求.%Accurate and real time acquirement of vehicle state variables in running is of great significance to vehicle chassis control. However, these key state variables are not easy to measure directly or cheaply. An improved strong track filter (ISTF) wh'i'ch-ts much more stable is introduced in this paper. By using a nonlinear 3 degree-of-freedom vehicle model including longitudinal motion, lateral motion, and yaw motion, a state estimation algorithm was established and applied to vehicle state estimation. Comparison was made between extended Kalman filter (EKF) and ISTF. A double lane change test was carried out on Carsim and Matlab/Simulink co-simulation as well as on a real vehicle. The results showed that ISTF is better than EKF in the estimating accuracy, tracking speed, and restraining noise. It was proved that ISTF can satisfy the requirements of vehicle state estimation.

  6. Vehicle infrared video colorization based on contour tracking%基于轮廓跟踪的车载红外视频彩色化方法

    Institute of Scientific and Technical Information of China (English)

    谯帅; 孙韶媛; 谷小婧; 戈曼

    2012-01-01

    A fast algorithm of vehicle infrared video colorization was proposed. Contour feature points tracking was utilized to get the contours and areas of different object classes in each frame. Characteristic colors of different classes were transferred to the corresponding areas in each frame. Firstly, we constructed the characteristic color sets of different classes of scenes. The characteristic colors of different scenes in the natural color images were extracted as the corresponding scenes' colors in the infrared images. Secondly, we clustered and segment the scenes in the key infrared video frame using the improved efficient K-Means clustering method, and the contour feature points were extracted. Thirdly, we tracked the contour feature points using the Kanade-Lucas-Tomasi (KLT) algorithm to get and correct their positions in the next frame. The B-spline interpolation method was used to reconstruct the contours. The contours and areas of different object classes in each frame were obtained. Finally, characteristic colors of different classes were transferred to the corresponding areas in each frame. Infrared video colorization was realized and the scenes were with reasonable colors. Experimental results show that the processing speed of the proposed method is nearly 5 times as fast as that of the algorithm based on motion estimation and it can give a natural color look to the infrared video.%提出一种车载红外视频快速彩色化方法,利用轮廓特征点跟踪获取每帧物体类别的轮廓区域,采用类别特征色彩对各区域传递色彩.构建各景物样本特征色彩集,以各类景物在自然彩色图像中表现出来的特征色彩作为红外图像中对应景物的色彩;利用改进的高效K-Means方法对红外关键帧进行聚类,得到分割区域,提取轮廓特征点;通过KLT算法跟踪特征点,得到其在下一帧中的位置并同时修正,采用B样条插值进行轮廓复原,得到该帧的各类别轮廓区域;最

  7. Road recognition and tracking for intelligent vehicle based on SOPC%基于SOPC的智能车辆道路识别与跟踪

    Institute of Scientific and Technical Information of China (English)

    黄海波; 蒋伟荣; 刘勇; 李学等; 徐娇

    2012-01-01

    对基于PC的道路识别系统进行改进,利用SOPC技术在以单片FPGA芯片为核心的硬件平台上,完成了包括3×3窗口模块、改进的快速中值滤波、基于自适应阈值的Sobel边缘检测和Hough变换等图像预处理功能.通过μC/OS-Ⅱ嵌入式实时操作系统来调度系统初始化、数据接收、道路识别、车辆控制和状态监控等任务,保证了视频导航的实时性要求.静态道路图像识别和实际道路行驶测试表明,该系统在一定干扰的情况下,成功实现了视频导航功能,具有较强的道路识别跟踪能力,且在速度、价格、灵活性上有很大的优势.%The road recognition system based on PC machine is improved. On the hardware platform with single FPGA chip as the core and based on SOPC technology, image processing function modules have been accomplished, which include a 3 × 3 window, improved fast median filtering, Sobel edge detection based on self-adapting threshold, and Hough transform. Embedded real-time operating system μC/OS-Ⅱ is used to schedule all the tasks, such as system initiation, data receiving, road recognition, vehicle control and state monitoring. Static state road image recognition and practical road running test show that under certain disturbance, the system has achieved video navigation function successfully, has strong road recognition and tracking ability, and has great advantages on speed, price and flexibility.

  8. Operational Testing of Satellite based Hydrological Model (SHM)

    Science.gov (United States)

    Gaur, Srishti; Paul, Pranesh Kumar; Singh, Rajendra; Mishra, Ashok; Gupta, Praveen Kumar; Singh, Raghavendra P.

    2017-04-01

    Incorporation of the concept of transposability in model testing is one of the prominent ways to check the credibility of a hydrological model. Successful testing ensures ability of hydrological models to deal with changing conditions, along with its extrapolation capacity. For a newly developed model, a number of contradictions arises regarding its applicability, therefore testing of credibility of model is essential to proficiently assess its strength and limitations. This concept emphasizes to perform 'Hierarchical Operational Testing' of Satellite based Hydrological Model (SHM), a newly developed surface water-groundwater coupled model, under PRACRITI-2 program initiated by Space Application Centre (SAC), Ahmedabad. SHM aims at sustainable water resources management using remote sensing data from Indian satellites. It consists of grid cells of 5km x 5km resolution and comprises of five modules namely: Surface Water (SW), Forest (F), Snow (S), Groundwater (GW) and Routing (ROU). SW module (functions in the grid cells with land cover other than forest and snow) deals with estimation of surface runoff, soil moisture and evapotranspiration by using NRCS-CN method, water balance and Hragreaves method, respectively. The hydrology of F module is dependent entirely on sub-surface processes and water balance is calculated based on it. GW module generates baseflow (depending on water table variation with the level of water in streams) using Boussinesq equation. ROU module is grounded on a cell-to-cell routing technique based on the principle of Time Variant Spatially Distributed Direct Runoff Hydrograph (SDDH) to route the generated runoff and baseflow by different modules up to the outlet. For this study Subarnarekha river basin, flood prone zone of eastern India, has been chosen for hierarchical operational testing scheme which includes tests under stationary as well as transitory conditions. For this the basin has been divided into three sub-basins using three flow

  9. 模拟自治车队行驶过程变工况速度跟踪控制%Speed Tracking Control for a Simulated Intelligent Vehicle Platoon under Variable Road Conditions

    Institute of Scientific and Technical Information of China (English)

    马育林; 吴青; 张蕊; 叶蕾; 严新平

    2011-01-01

    the intelligent vehicle simulation system by adding acceleration sensor, the speed tracking controller is designed by fuzzy sliding mode control based on equivalent control. A given reference speed can be globally stably tracked when the intelligent vehicle drives in variable road conditions. The simulation results show the effectiveness and stability of the controller, the study on the control for a platoon of autonomous vehicles under the coordination between vehicle and highway can be promoted by theories and experiments.

  10. Cross-iterative Algorithm and Its Application to the Analysis of Vehicle-track Nonlinear Coupling Systems%车辆-轨道非线性耦合系统交叉迭代算法及应用

    Institute of Scientific and Technical Information of China (English)

    雷晓燕; 吴神花; 张斌

    2016-01-01

    运用有限元法建立车辆-轨道非线性耦合系统振动分析模型,该模型包含车辆、轨道两个子系统,其中车辆子系统为附有二系弹簧的整车模型,轨道结构子系统为离散的三层弹性梁模型。两子系统通过轮轨非线性接触力和位移协调条件实现耦合。针对车辆-轨道非线性耦合系统动力学方程提出了交叉迭代算法。为加速迭代收敛速度,引入松弛法对轮轨接触力进行修正。为证明算法的正确性,进行了算例验证。同时还给出了CRH3高速动车在有砟轨道上运行时引起车辆和轨道振动的实例,分析中考虑了轮轨线性和非线性接触及不同列车速度对车辆和轨道结构振动的影响。计算结果表明交叉迭代算法具有程序编制简单、收敛速度快、用时少、精度高的优点;采用轮轨线性接触模型得到的车辆和轨道结构的动力响应比轮轨非线性接触模型得到的结果要大,其中位移、加速度最大值和振幅增大范围约在15%以内,轮轨接触力最大值和振幅增大范围约在5%以内。%A model for dynamic analysis of a vehicle-track nonlinear coupling system is established by finite element method. The system is divided into two subsystems, i.e. the vehicle subsystem considered as the secondary spring vehicle model and the track subsystem regarded as the model of three discrete elastic beams. Coupling of the two systems is achieved by equilibrium conditions of wheel-rail nonlinear contact forces and geometrical compatibility conditions. A cross-iterative algorithm is presented to solve the dynamics equations of the vehicles-track nonlinear coupling system. In order to accelerate the iterative convergence rate, the relaxation technique is employed to correct the wheel-rail contact force. Comparing with the example in a reference, the correctness of the algorithm is verified. Examples of the vehicle and track vibration induced by the high

  11. 履带车辆液压机械差速转向系统参数优化%Parameter optimization of hydro-mechanic differential turning system for tracked vehicle

    Institute of Scientific and Technical Information of China (English)

    曹付义; 周志立; 徐立友

    2013-01-01

    液压机械差速转向系统是履带车辆的一种双功率流转向系统,其参数设计属于多参数、多目标、非线性优化问题。该文在对优化参数及评价目标进行理论分析的基础上,建立了包括履带车辆转向动力性、转向灵活性和转向快速性等液压机械差速转向系统参数优化数学模型,根据遗传算法的基本思想,采用层次化划分问题空间方法处理系统参数之间的相互约束和耦合问题,给出了一种基于遗传算法的履带车辆液压机械差速转向系统参数优化方法,结合实例样车设计需要优化出了履带车辆液压机械差速转向系统参数,与已得到实车验证的系统参数偏差最大不超过3.5%,表明所给出的优化方法可满足履带车辆液压机械差速转向系统参数实际工程设计需要。%The hydro-mechanical differential turning system is the double power flow turning system made up of a hydraulic transmission, mechanical transmission, and planetary transmission. It can allow tracked vehicles to accomplish a continuously step-less turning process and exhibits high working efficiency and light operation force. The turning system has good application prospects for tracked tractors, construction machinery, armored vehicle and other heavy machinery. Because the turning system contains several parameters, constraint and coupling are among these parameters. The system parameter design is addressed by a multi-parameter, multi-goal, nonlinear optimization question. Known from literature, the optimized parameters include the characteristic coefficient of planet row, parameters of the hydraulic closed-loop system (rated pressure, motor displacement), rear transmission ratio of the motor, the fixed axis transmission ratio, and other parameters. The turning dynamic, turning flexibility, and turning speed of a tracked vehicle are the evaluation objectives of system parameter optimization. The turning dynamic is

  12. Miniature Autonomous Robotic Vehicle (MARV)

    Energy Technology Data Exchange (ETDEWEB)

    Feddema, J.T.; Kwok, K.S.; Driessen, B.J.; Spletzer, B.L.; Weber, T.M.

    1996-12-31

    Sandia National Laboratories (SNL) has recently developed a 16 cm{sup 3} (1 in{sup 3}) autonomous robotic vehicle which is capable of tracking a single conducting wire carrying a 96 kHz signal. This vehicle was developed to assess the limiting factors in using commercial technology to build miniature autonomous vehicles. Particular attention was paid to the design of the control system to search out the wire, track it, and recover if the wire was lost. This paper describes the test vehicle and the control analysis. Presented in the paper are the vehicle model, control laws, a stability analysis, simulation studies and experimental results.

  13. Cooperative ground moving target track method using two unmanned aerial vehicles%一种双无人机协同跟踪地面移动目标方法

    Institute of Scientific and Technical Information of China (English)

    符小卫; 侯建永; 高晓光; 刘重

    2013-01-01

    This paper investigated the cooperative tracking of a ground moving target using two unmanned aerial vehicles under communication delay,and constructed an algorithm model.Considering the communication delay,it proposed a data fusion method combined with the recursive least squares filtering and the weighted least squres.Then it built the recursive least squares filtering for the prediction of target states,designed a trajectory planning algorithm based on receding horizon and the distributed genetic algorithm to implement the task of cooperative target tracking using two unmanned aerial vehicles.The fitness function consisted of several components including the distance of vehicles and target,the communication distance of vehicles,the communication angle of vehicles.Simulation studies show the cooperative track algorithm can implement the track task well;compared to one vehicle track the target,the position error decreases obviously,the position error during to the communication delay can decrease.%针对通信延时情况下双无人机协同跟踪地面移动目标问题进行研究,构建了基于分布式遗传算法和滚动时域优化结合的目标跟踪航迹规划算法模型.考虑到通信延时会增加目标状态信息数据融合时的误差,导致无人机跟踪任务效果变差,结合递推最小二乘滤波和加权最小二乘估计设计了融合方法,来融合处理目标状态信息;考虑到无人机对目标的观测效果与未来时刻的目标状态信息密切相关,采用递推最小二乘滤波预测目标的状态信息,结合分布式遗传算法和滚动时域优化设计了双无人机目标跟踪航迹规划算法.适应度函数考虑了无人机和目标之间的距离、无人机之间的通信距离、无人机之间的通信角度.仿真结果表明:该协同跟踪方法能够较好地完成跟踪任务;与一架无人机跟踪相比误差明显减小,并且可以减小通信延时带来的跟踪误差.

  14. 基于 eM -Plant 的医用轨道物流传输系统仿真与优化%Simulation and Optimization of Medical Track Vehicle System Based on eM-Plant

    Institute of Scientific and Technical Information of China (English)

    张中; 臧铁钢; 王静静

    2014-01-01

    以轨道物流传输系统为分析对象和参照依据,根据科室间距离和物流传输系统的运输物流量,提出对医院科室布局的相应优化。在此基础上完成系统建模,将问题抽象化为二次分配问题并加以分析。通过物流仿真软件eM-Plant建立计算机仿真模型,使用软件自带的遗传算法工具GAwizard完成医用轨道物流传输系统的仿真与优化。%It takes the medical track vehicle system as research object , proposes a method for hospital depart-ments layout optimization according to the transmission distance and logistics capacity between every department . On this basis, it establishes the system model , abstracts the problem into quadratic assignment model .It gener-ates the computer simulation model with eM -Plant and the genetic algorithm tool GAwizard , realizes the simula-tion and optimization of medical track vehicle system .

  15. Towards a satellite-based sea ice climate data record

    Science.gov (United States)

    Meier, W. N.; Fetterer, F.; Stroeve, J.; Cavalieri, D.; Parkinson, C.; Comiso, J.; Weaver, R.

    2005-12-01

    Sea ice plays an important role in the Earth's climate through its influence on the surface albedo, heat and moisture transfer between the ocean and the atmosphere, and the thermohaline circulation. Satellite data reveal that since 1979, summer Arctic sea ice has, overall, been declining at a rate of almost 8%/decade, with recent summers (beginning in 2002) being particularly low. The receding sea ice is having an effect on wildlife and indigenous peoples in the Arctic, and concern exists that these effects may become increasingly severe. Thus, a long-term, ongoing climate data record of sea ice is crucial for tracking the changes in sea ice and for assessing the significance of long-term trends. Since the advent of passive microwave satellite instruments in the early 1970s, sea ice has been one of the most consistently monitored climate parameters. There is now a 27+ year record of sea ice extent and concentration from multi-channel passive microwave radiometers that has undergone inter-sensor calibration and other quality controls to ensure consistency throughout the record. Several algorithms have been developed over the years to retrieve sea ice extent and concentration and two of the most commonly used algorithms, the NASA Team and Bootstrap, have been applied to the entire SMMR-SSM/I record to obtain a consistent time series. These algorithms were developed at NASA Goddard Space Flight Center and are archived at the National Snow and Ice Data Center. However, the complex surface properties of sea ice affect the microwave signature, and algorithms can yield ambiguous results; no single algorithm has been found to work uniformly well under all sea ice conditions. Thus there are ongoing efforts to further refine the algorithms and the time series. One approach is to develop data fusion methods to optimally combine sea ice fields from two or more algorithms. Another approach is to take advantage of the improved capabilities of JAXA's AMSR-E sensor on NASA's Aqua

  16. Advanced Multipath Mitigation Techniques for Satellite-Based Positioning Applications

    Directory of Open Access Journals (Sweden)

    Mohammad Zahidul H. Bhuiyan

    2010-01-01

    Full Text Available Multipath remains a dominant source of ranging errors in Global Navigation Satellite Systems (GNSS, such as the Global Positioning System (GPS or the future European satellite navigation system Galileo. Multipath is generally considered undesirable in the context of GNSS, since the reception of multipath can make significant distortion to the shape of the correlation function used for time delay estimation. However, some wireless communications techniques exploit multipath in order to provide signal diversity though in GNSS, the major challenge is to effectively mitigate the multipath, since we are interested only in the satellite-receiver transit time offset of the Line-Of-Sight (LOS signal for the receiver's position estimate. Therefore, the multipath problem has been approached from several directions in order to mitigate the impact of multipath on navigation receivers, including the development of novel signal processing techniques. In this paper, we propose a maximum likelihood-based technique, namely, the Reduced Search Space Maximum Likelihood (RSSML delay estimator, which is capable of mitigating the multipath effects reasonably well at the expense of increased complexity. The proposed RSSML attempts to compensate the multipath error contribution by performing a nonlinear curve fit on the input correlation function, which finds a perfect match from a set of ideal reference correlation functions with certain amplitude(s, phase(s, and delay(s of the multipath signal. It also incorporates a threshold-based peak detection method, which eventually reduces the code-delay search space significantly. However, the downfall of RSSML is the memory requirement which it uses to store the reference correlation functions. The multipath performance of other delay-tracking methods previously studied for Binary Phase Shift Keying-(BPSK- and Sine Binary Offset Carrier- (SinBOC- modulated signals is also analyzed in closed loop model with the new Composite

  17. Research on relationship between track condition and metro vehicle vibration%路况与地铁车辆振动关系的测试分析研究

    Institute of Scientific and Technical Information of China (English)

    张华超; 张小栋; 曹广忠

    2011-01-01

    With the development of underground rail, the problem that vehicle vibration affects the vehicle's life-span and harms the health of the passenger has been concerned. A vibration test system has been formed with data collecting instrument and acceleration sensors to collect the signals of the metro vehicle floor when it running at the ATO (auto train operation) mode in the tunnel. The changes of vehicle vibration signal were analyzed v.s. the changes correspond to the route condition, such as curve, slope, and so on. Relationships between the road condition and vehicle vibration were established. The analysis result shows that, the vehicle vibration not only be affected by the structure of the vehicle itself and the geological condition of track, but also has close relationship with the route condition.%随着地下轨道交通的发展,地铁车辆振动对车辆寿命的影响和对人体健康造成损害的问题日益受到人们的重视.利用数据采集仪和振动加速度传感器组建振动测试系统,当地铁车辆在隧道内按照正常运行模式运行时,采集驾驶室及客室地板上的振动信号,分析车辆振动信号随隧道内各种不同路况(如弯道,上、下坡道等)的变化产生的变化规律,得到车辆振动与路况之间的关系.结果表明,地铁车辆振动除受本身结构和轨道铺设的地质条件影响,还与其所运行的轨道线路路况有着密切的关系.

  18. Towards a protocol for validating satellite-based Land Surface Temperature: Theoretical considerations

    Science.gov (United States)

    Schneider, Philipp; Ghent, Darren J.; Corlett, Gary C.; Prata, Fred; Remedios, John J.

    2013-04-01

    Land Surface Temperature (LST) and emissivity are important parameters for environmental monitoring and earth system modelling. LST has been observed from space for several decades using a wide variety of satellite instruments with different characteristics, including both platforms in low-earth orbit and in geostationary orbit. This includes for example the series of Advanced Very High Resolution Radiometers (AVHRR) delivering a continuous thermal infrared (TIR) data stream since the early 1980s, the series of Along-Track Scanning Radiometers (ATSR) providing TIR data since 1991, and the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments onboard NASA's Terra and Aqua platforms, providing data since the year 2000. In addition, the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard of the geostationary Meteosat satellites is now providing LST at unprecedented sub-hour frequency. The data record provided by such instruments is extremely valuable for a wide variety of applications, including climate change, land/atmosphere feedbacks, fire monitoring, modelling, land cover change, geology, crop- and water management. All of these applications, however, require a rigorous validation of the data in order to assess the product quality and the associated uncertainty. Here we report on recent work towards developing a protocol for validation of satellite-based Land Surface Temperature products. Four main validation categories are distinguished within the protocol: A) Comparison with in situ observations, B) Radiance-based validation, C) Inter-comparison with similar LST products, and D) Time-series analysis. Each category is further subdivided into several quality classes, which approximately reflect the validation accuracy that can be achieved by the different approaches, as well as the complexity involved with each method. Advice on best practices is given for methodology common to all categories. For each validation category, recommendations

  19. CDC Vital Signs: Motor Vehicle Crash Deaths

    Science.gov (United States)

    ... government is Tracking the nation’s progress in reducing crash injuries and deaths. www.cdc.gov/psr/national-summary/ ... Motor Vehicle Crash Deaths Vital Signs: Motor Vehicle Crash Injuries Vital Signs: Child Passenger Safety CDC: Child Passenger ...

  20. Cooperative tracking of ground moving target using unmanned aerial vehicles in cluttered environment%复杂环境下多无人机协作式地面移动目标跟踪

    Institute of Scientific and Technical Information of China (English)

    王林; 彭辉; 朱华勇; 沈林成

    2011-01-01

    针对多无人机(UAV)协同地面移动目标跟踪问题展开研究.提出一种基于主动感知的问题求解框架,建立多UAV协同目标跟踪问题模型;在此基础上,采用分布式无色信息滤波实现目标状态融合估计与预测;然后,基于预测目标状态,结合滚动时域控制与遗传算法设计一种多UAV在线协同航迹规划算法.仿真结果表明:结合预测目标状态在线优化UAV航迹能够获得更好的目标跟踪性能.%We investigate the cooperative tracking of a ground moving target in a cluttered environment by using unmanned aerial vehicles(UAV). Firstly, a model the cooperative target tracking by UAV is developed based on active sensing;secondly, a distributed unscented information filter is built for the estimation fusion and the prediction of target states. Finally, an online trajectory planning algorithm based on the receding horizon control and the genetic algorithm is designed and implemented, with the predicted target states as the inputs to this planning algorithm. Numerical simulations demonstrate that the proposed method effectively improves the performance of target tracking.

  1. Severe thunderstorm activity over Bihar on 21st April, 2015: a simulation study by satellite based Nowcasting technique

    Science.gov (United States)

    Goyal, Suman; Kumar, Ashish; Sangar, Ghansham; Mohapatra, M.

    2016-05-01

    Satellite based Nowcasting technique is customized version of Forecast and Tracking the Evolution of Cloud Clusters (ForTraCC), it uses the extrapolation technique that allows for the tracking of Mesoscale convective systems (MCS) radiative and morphological properties and forecasts the evolution of these properties (based on cloud-top brightness temperature and area of the cloud cluster) up to 360 minutes, using infrared satellite imagery. The Thermal Infrared (TIR) channel of the weather satellite has been broadly used to study the behaviour of the cloud systems associated with deep convection. The main advantage of this approach is that for most of the globe the best statistics can only be obtained from satellite observations. Such a satellite survey would provide the statistics of MCSs covering the range of meteorological conditions needed to generalize the result and on the other hand only satellite observations can cover the very large range of space and time scale. The algorithm script is taken from Brazilian Scientist Dr. Danial Vila and implemented it into the Indian environment and made compatible with INSAT-3D hdf5 data format. For Indian region it utilizes the INSAT-3D satellite data of TIR1 (10.8 μm) channel and creates nowcast. The output is made compatible with GUI based software MIAS by generating the output in hdf5 format for better understanding and analysis of forecast. The main features of this algorithm are detection of Cloud Cluster based on Cloud Top Brightness Temperature (CTBT) and area i.e. ≤235 ºK and ≥2400 km2 respectively. The tracking technique based on MCS overlapping areas in successive images. The script has been automized in Auxiliary Data Processing System (ADPS) and generating the forecast file in every half an hour and convert the output file in geotiff format. The geotiff file is easily converted into KMZ file format using ArcGIS software to overlay it on google map and hosted on the web server.

  2. Validation of PV performance models using satellite-based irradiance measurements : a case study.

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Joshua S.; Parkins, Andrew (Clean Power Research); Perez, Richard (University at Albany)

    2010-05-01

    Photovoltaic (PV) system performance models are relied upon to provide accurate predictions of energy production for proposed and existing PV systems under a wide variety of environmental conditions. Ground based meteorological measurements are only available from a relatively small number of locations. In contrast, satellite-based radiation and weather data (e.g., SUNY database) are becoming increasingly available for most locations in North America, Europe, and Asia on a 10 x 10 km grid or better. This paper presents a study of how PV performance model results are affected when satellite-based weather data is used in place of ground-based measurements.

  3. Efficient enhancing scheme for TCP performance over satellite-based internet

    Institute of Scientific and Technical Information of China (English)

    Wang Lina; Gu Xuemai

    2007-01-01

    Satellite link characteristics drastically degrade transport control protocol (TCP) performance. An efficient performance enhancing scheme is proposed. The improvement of TCP performance over satellite-based Intemet is accomplished by protocol transition gateways at each end ora satellite link. The protocol which runs over a satellite link executes the receiver-driven flow control and acknowledgements- and timeouts-based error control strategies. The validity of this TCP performance enhancing scheme is verified by a series of simulation experiments. Results show that the proposed scheme can efficiently enhance the TCP performance over satellite-based Intemet and ensure that the available bandwidth resources of the satellite link are fully utilized.

  4. GPS Metric Tracking Unit

    Science.gov (United States)

    2008-01-01

    As Global Positioning Satellite (GPS) applications become more prevalent for land- and air-based vehicles, GPS applications for space vehicles will also increase. The Applied Technology Directorate of Kennedy Space Center (KSC) has developed a lightweight, low-cost GPS Metric Tracking Unit (GMTU), the first of two steps in developing a lightweight, low-cost Space-Based Tracking and Command Subsystem (STACS) designed to meet Range Safety's link margin and latency requirements for vehicle command and telemetry data. The goals of STACS are to improve Range Safety operations and expand tracking capabilities for space vehicles. STACS will track the vehicle, receive commands, and send telemetry data through the space-based asset, which will dramatically reduce dependence on ground-based assets. The other step was the Low-Cost Tracking and Data Relay Satellite System (TDRSS) Transceiver (LCT2), developed by the Wallops Flight Facility (WFF), which allows the vehicle to communicate with a geosynchronous relay satellite. Although the GMTU and LCT2 were independently implemented and tested, the design collaboration of KSC and WFF engineers allowed GMTU and LCT2 to be integrated into one enclosure, leading to the final STACS. In operation, GMTU needs only a radio frequency (RF) input from a GPS antenna and outputs position and velocity data to the vehicle through a serial or pulse code modulation (PCM) interface. GMTU includes one commercial GPS receiver board and a custom board, the Command and Telemetry Processor (CTP) developed by KSC. The CTP design is based on a field-programmable gate array (FPGA) with embedded processors to support GPS functions.

  5. An Antenna Tracking Method Using Phased Array and Servo for Vehicle Satellite Communication on the Move%相控阵结合伺服辅助的车载动中通天线跟踪方法

    Institute of Scientific and Technical Information of China (English)

    蒋文丰

    2016-01-01

    天线跟踪功能是车载动中通系统( SOTM)提供无线通信能力的前提,相控阵天线能提供较好的跟踪性能,但是存在波束扫描范围有限的问题。为实现相控阵天线全方位跟踪能力,提出了一种相控阵+伺服辅助的方法。给出了算法数据处理流程,并完成了原理样机设计。根据原理样机工作原理给出了跟踪角误差计算公式,测试结果与计算结果相符。测试结果表明:在(57.88~115.76)。/s角速度下,通信链路信噪比损失小于0.5 dB。%The antenna tracking function is the foundation for the vehicle satellite communication on the move( SOTM) to offer wireless communications,and the phased array antenna can provide better tracking performance,but the beam scanning range is limited. In order to realize the phased array antenna tracking in the entire orientation,a method using phased array antenna and servo is presented. The data processing flow of algorithm is provided, and the prototype has been developed. According to the prototype working principle,the formula to calculate the tracking angle error is given. The test result matches with the calcu-lating result,and the signal-to-noise ratio(SNR) loss is smaller than 0. 5 dB at the angle speed between (57. 88~115. 76)./s.

  6. Satellite-based empirical models linking river plume dynamics with hypoxic area andvolume

    Science.gov (United States)

    Satellite-based empirical models explaining hypoxic area and volume variation were developed for the seasonally hypoxic (O2 < 2 mg L−1) northern Gulf of Mexico adjacent to the Mississippi River. Annual variations in midsummer hypoxic area and ...

  7. Satellite-Based actual evapotranspiration over drying semiarid terrain in West-Africa

    NARCIS (Netherlands)

    Schuttemeyer, D.; Schillings, Ch.; Moene, A.F.; Bruin, de H.A.R.

    2007-01-01

    A simple satellite-based algorithm for estimating actual evaporation based on Makkink¿s equation is applied to a seasonal cycle in 2002 at three test sites in Ghana, West Africa: at a location in the humid tropical southern region and two in the drier northern region. The required input for the algo

  8. A Study on Lateral Control Method for the Path Tracking of Intelligent Vehicles%智能车辆路径跟踪横向控制方法的研究

    Institute of Scientific and Technical Information of China (English)

    赵熙俊; 陈慧岩

    2011-01-01

    A lateral control system for the path tracking of intelligent vehicles is proposed. The control system consists of a desired heading error generator based on vehicle-road kinematic relation and a feedback control system using robust PID controller based on vehicle-road dynamics model. Based on the analysis on system characteristics, a robust fixed gain PID controller and prefilter with optimum ITAE performance indicator are designed for a base speed. And after the analysis on the effects of longitudinal speed on feedback system, the-applicable speed range for the parameters of fixed gain PID is given. The effects of PID parameters on closed-loop feedback system are analyzed and the PID parameters for other speed range are adjusted. The results of validation test on real vehicle show that the lateral control system proposed has good performance in path tracking.%提出了一种智能车辆的路径跟踪横向控制系统.系统由期望航向偏差生成器和反馈控制系统两部分组成.期望航向偏差根据车辆-道路之间运动学关系来确定;而反馈控制系统则采用基于车辆-道路动力学模型的鲁棒PID控制器.在分析系统特性的基础上设计以某一速度为基准的、ITAE性能指标最优的固定增益鲁棒PID控制器和前置滤波器.在分析纵向速度对反馈系统影响的前提下,给出固定增益PID参数所适用的车速范围;分析了PID参数对闭环反馈系统的影响,调整了其他车速区间的PID参数.实车试验验证的结果表明,所提出的路径跟踪横向控制系统具有良好的路径跟踪能力.

  9. Assessment of the aerosol optical depths measured by satellite-based passive remote sensors in the Alberta oil sands region

    Science.gov (United States)

    Sioris, Christopher E.; McLinden, Chris A.; Shephard, Mark W.; Fioletov, Vitali E.; Abboud, Ihab

    2017-02-01

    Several satellite aerosol optical depth (AOD) products are assessed in terms of their data quality in the Alberta oil sands region. The instruments consist of MODIS (Moderate Resolution Imaging Spectroradiometer), POLDER (Polarization and Directionality of Earth Reflectances), MISR (Multi-angle Imaging SpectroRadiometer), and AATSR (Advanced Along-Track Scanning Radiometer). The AOD data products are examined in terms of multiplicative and additive biases determined using local Aerosol Robotic Network (AERONET) (AEROCAN) stations. Correlation with ground-based data is used to assess whether the satellite-based AODs capture day-to-day, month-to-month, and spatial variability. The ability of the satellite AOD products to capture interannual variability is assessed at Albian mine and Shell Muskeg River, two neighbouring sites in the northern mining region where a statistically significant positive trend (2002-2015) in PM2.5 mass density exists. An increasing trend of similar amplitude (˜ 5 % year-1) is observed in this northern mining region using some of the satellite AOD products.

  10. Patrol car and agent tracking/suspect tagging and tracking

    Science.gov (United States)

    Wilkins, Steven C.

    1997-01-01

    Emerging technologies in the field of law enforcement are providing today's law enforcement personnel with the advantage of an innovative and faster means of providing safety and service to the public. The use of open such technology, the Automatic Vehicle Locator (AVL) tracking device, is fast becoming a commonplace and cost-effective solution for agencies to efficiently command and control their 'officer' assets. Through the use of AVL's global positioning satellite-based system, the response time of law enforcement is greatly enhanced by permitting a dispatcher to visually identify and assign the officer closest to the location of an accident or incident. The system is effective in reducing delays due to highway blockages, improving the level of protection to the motoring public, and promoting the flow of traffic on busy freeways. Likewise, an officer or agent in distress can be assured that a dispatcher will be constantly aware of his or her location in the field. In the 1990's the demands on law enforcement agencies have grown tremendously. this is due primarily to population increases, limited funding or resources, and increases in drug, property and violent crimes. Frequently, the automobile is used for escape after the commission of these crimes. This often results in high speed pursuits involving law enforcement agencies. In California, by statute, the California Highway Patrol is the central repository for data regarding all pursuits involving state and local law enforcement agencies. Statistics show that more than 10 percent of pursuits result in injuries to the violator and/or innocent bystanders. Most pursuits last less than 10 minutes, and the AVL system provides a tremendous advantage to law enforcement's ability to immediately deploy and direct units into pursuits for rapid closure of the incident. AVL systems not only reduce the risk of personal injury by minimizing public exposure to the unsafe incident, but also enhance officer safety during the

  11. Tracking telecommuting

    Energy Technology Data Exchange (ETDEWEB)

    Stastny, P.

    2007-03-15

    Many employees are now choosing to work from home using laptops and telephones. Employers in the oil and gas industry are now reaping a number of benefits from their telecommuting employees, including increased productivity; higher levels of employee satisfaction, and less absenteeism. Providing a telecommunication option can prove to be advantageous for employers wishing to hire or retain employees. Telecommuting may also help to reduce greenhouse gas (GHG) emissions. This article provided details of Teletrips Inc., a company that aids in the production of corporate social responsibility reports. Teletrips provides reports that document employee savings in time, vehicle depreciation maintenance, and gasoline costs. Teletrips currently tracks 12 companies in Calgary, and plans to grow through the development of key technology partnerships. The company is also working with the federal government to provide their clients with emission trading credits, and has forged a memorandum of understanding with the British Columbia government for tracking emissions. Calgary now openly supports telecommuting and is encouraging businesses in the city to adopt telecommuting on a larger scale. It was concluded that the expanding needs for road infrastructure and the energy used by cars to move workers in and out of the city are a massive burden to the city's tax base. 1 fig.

  12. Design and Test of Pneumatic AMT Control Device for Tracked Armored Vehicle%履带式装甲车气动 AMT 机构设计与试验

    Institute of Scientific and Technical Information of China (English)

    李国强; 王兴野; 张进秋; 张磊

    2014-01-01

    针对某型履带式装甲车换挡操纵费力、驾驶员劳动强度大等问题,分析了该型装甲车变速操纵装置的结构和原理,根据该型车辆的结构特点和换挡过程中对换挡机构的要求,设计了气动 AMT 操纵机构,给出了关键元件的确定原则。对该型装甲车进行了实车改装与试验,试验结果表明:该气动 AMT 操纵机构工作稳定可靠,能够快速实现平稳、准确换挡,满足了车辆自动变速系统的要求。%In allusion to that it is strenuous to shift gears for a certain type of tracked armored vehicle, and the labor intensity is high for the drivers,the structure and work principle of the vehicle’s gearshift control device is analyzed.According to its structure characteristics and the request in the process of gearshift,a pneumatic AMT control device is designed and the designating principle of the key component is presented.After having a modification on the tracked armored vehicle and conducting a test,it is veri-fied that the new designed device works stably and reliably,achieves the target to shift gears stably and precisely,satisfies the request of the vehicle’s automatic transmission system.

  13. Capture Scheme of the Antenna in Ka-band for Launch Vehicle Based on Tracking and Data Relay Satellite%运载火箭Ka频段天基测控的天线捕获方法

    Institute of Scientific and Technical Information of China (English)

    宫长辉; 曾贵明; 张恒

    2011-01-01

    In order to transmit the space-based signal, the capture and track between the tracking and data relay satellite(TDRS) antenna and the user's aerocraft antenna should be completed firstly. In this paper, the uncertain area of the antenna scan is analyzed, adopting antenna-scan capture scheme for capturing the antenna on TORS by the phased-array antenna on launch vehicle. The values of the antenna array and EIRP are conformed and the capture time is given by computer simulation.%为实现天基信息的传输,首先要完成中继卫星天线与用户飞行器天线之间的捕获与跟踪.针对箭载相控阵天线对中继卫星的捕获,采用Ka频段相控阵天线扫描捕获策略,分析了天线扫描的不确定区域,确定了天线阵元数及EIRP值,给出了捕获时间的仿真结果,为工程应用提供参考.

  14. Application of Neural Network-aided Kalman Filtering Technique in Target Tracking of Hypersonic Vehicle%神经网络校正的EKF在高超声速目标跟踪中的应用

    Institute of Scientific and Technical Information of China (English)

    周延延; 王柯; 高育鹏; 李小兵

    2014-01-01

    针对临近空间高超声速目标高度非线性、强耦合、高机动、时变参数、和独特气动特性等特点,综合运用军事运筹学理论与方法、系统建模技术、神经网络技术以及计算机仿真等,提出基于神经网络校正的扩展卡尔曼滤波(EKF)算法,并在高超声速目标跟踪中进行了应用研究。采取神经网络的学习能力来克服卡尔曼滤波发散问题,通过卡尔曼滤波后加一级误差处理环节使滤波收敛。仿真结果表明:该算法在目标发生较大机动时仍能保持较高的跟踪精度。%Aiming at the characteristics of nonlinearity,strong coupling and maneuvering,parameter varity and unique aerodynamics and so on in hypersonic vehicle,the method of neural network aided Kalman fil-tering for the near space hypersonic vehicle is proposed,and be applied to study of hypersonic target track-ing by synthetically applying military operational research theory and method,system modeling technique, neural network technique and computer simulation technique,etc.The basic thought is making use of study capability of BP neural network to overcome the divergence problem in extended Kalman filter.After the extended Kalman filter,adding an error processing section makes filter concentrated.The simulation study shows that the algorithm is better than ones by extended Kalman filter.The Algorithm will have certain reference in target interception of hypersonic vehicle in Near Space.

  15. 地铁钢轨波磨对车辆和轨道动态行为的影响%Effect of metro rail corrugation on dynamic behaviors of vehicle and track

    Institute of Scientific and Technical Information of China (English)

    李伟; 曾全君; 朱士友; 樊嘉峰; 金学松

    2015-01-01

    The characteristics of rail corrugation were measured by using corrugation analysis trolley,the vibration accelerations of vehicle and track components were measured by using acceleration and displacement sensors before and after rail grinding,and the effect of rail corrugation on the vibrations of vehicle and track components was analyzed.Vehicle-track coupling dynamics model was established to analyze the effect of rail corrugation on wheel/rail interaction force and to determine the limit value of rail grinding.Study result shows that the main wavelength of rail corrugation is 30-40 mm and the secondary wavelength is 16 mm.The vibrations of railhead and fastener clip at 650-800 Hz and the vibrations of axle box at 670-800 Hz are in accordance with the passing vibration behaviors of vehicle with wavelength of 30-40 mm. So the short-pitch rail corrugation leads to the strong vibration of metro vehicle and track components,and it is the main cause of fatigue fracture of primary suspension springs and track fastener clips.Rail grinding can effectively solve fatigue fracture problem.Before rail grinding the root mean square values of vibration accelerations of railhead,fastener clip,sleeper and ballast bed are 243.4,309.3,17.1 and 2.6 m ·s-2 respectively,and after rail grinding they decrease to 51.5,8.8,1.5 and 0.5 m·s-2 respectively.When the depth of rail corrugation is 0.1 mm,wheel/rail vertical forces are 307 and 109 kN with wavelengths of 35 and 80 mm respectively,and wheel/rail transverse forces are 56 and 25 kN with wavelengths of 35 and 80 mm respectively. So wheel/rail vertical and transverse forces are very sensitive to the wavelength of rail corrugation.When vehicle operation speed is 90-120 km·h-1 ,the depth of rail corrugation with wavelength of 35 mm is 0.05-0.08 mm according to the limited criterion of wheel unloading rate,and the depth is 0.03-0.06 mm according to the limited criterion of wheel/rail vertical force.So rail grinding should be carried

  16. Sensors in Unmanned Robotic Vehicle

    Directory of Open Access Journals (Sweden)

    B. Rohini

    2008-05-01

    Full Text Available Unmanned tracked vehicles are developed for deployment in dangerous zones that are notsafe for human existence. These vehicles are to be fitted with various sensors for safe manoeuvre.Wide range of sensors for vehicle control, vision, and navigation are employed. The main purposeof the sensors is to infer the intended parameter precisely for further utilisation. Software isinseparable part of the sensors and plays major role in scaling, noise reduction, and fusion.Sensor fusion is normally adapted to enhance the decision-making. Vehicle location  andorientation can be sensed through global positioning system, accelerometer, gyroscope, andcompass. The unmanned vehicle can be navigated with the help of CCD camera, radar, lidar,ultrasonic sensor, piezoelectric sensor, microphone, etc.  Proximity sensors like capacitive andRF proximity detectors can detect obstacles in close vicinity.  This paper presents an overviewof sensors normally deployed in unmanned tracked vehicles.

  17. Implementing earth observation and advanced satellite based atmospheric sounders for water resource and climate modelling

    DEFF Research Database (Denmark)

    Boegh, E.; Dellwik, Ebba; Hahmann, Andrea N.;

    This paper discusses preliminary remote sensing (MODIS) based hydrological modelling results for the Danish island Sjælland (7330 km2) in relation to project objectives and methodologies of a new research project “Implementing Earth observation and advanced satellite based atmospheric sounders...... for effective land surface representation in water resource modeling” (2009- 2012). The purpose of the new research project is to develop remote sensing based model tools capable of quantifying the relative effects of site-specific land use change and climate variability at different spatial scales....... For this purpose, a) internal catchment processes will be studied using a Distributed Temperature Sensing (DTS) system, b) Earth observations will be used to upscale from field to regional scales, and c) at the largest scale, satellite based atmospheric sounders and meso-scale climate modelling will be used...

  18. Pneumatic vehicle. Research and design

    Directory of Open Access Journals (Sweden)

    Lokodi Zsolt

    2011-12-01

    Full Text Available This experimental vehicle was designed for an international competition organized by Bosch Rexroth yearly in Hungary. The purpose of this competition is to design, build and race vehicles with a fuel source of compressed gas. The race consists of multiple events: longest run distance, the smartness track and the best acceleration event. These events test to the limit the capabilities of the designed vehicles.

  19. Satellite-based assessment of climate controls on US burned area

    OpenAIRE

    D. C. Morton; G. J. Collatz; Wang, D.; Randerson, J. T.; Giglio, L.; Chen, Y.

    2013-01-01

    Climate regulates fire activity through the buildup and drying of fuels and the conditions for fire ignition and spread. Understanding the dynamics of contemporary climate–fire relationships at national and sub-national scales is critical to assess the likelihood of changes in future fire activity and the potential options for mitigation and adaptation. Here, we conducted the first national assessment of climate controls on US fire activity using two satellite-based estimates of monthly burne...

  20. The Analysis and Creation of Track Irregularities Using TRAKVU

    OpenAIRE

    1998-01-01

    The accuracy of the results from a rail vehicle dynamic model is dependent on the realism of the track input to the model. An important part of the track input is the irregularities that exist on actual track. This study analyzes the irregularities inherent in railroad track geometry data, and provides an analytical method for creating track data with the irregularities for use as the input to a dynamic model. Track data, measured from various classes of track, was ...

  1. 未知风场扰动下无人机三维航迹跟踪鲁棒最优控制%Robust Optimal Control for Unmanned Aerial Vehicles'' Three-dimensional Trajectory Tracking in Wind Disturbance

    Institute of Scientific and Technical Information of China (English)

    张坤; 高晓光

    2015-01-01

    This paper presents a robust optimal guidance control law for precise three-dimensional (3D) trajectory tracking of an Unmanned Aerial Vehicle (UAV) in wind disturbance. The wind disturbance is considered in the UAV''s kinematic model. The reference path is considered as a trajectory of a virtual target. Feedback linearization is used to transform the nonlinear dynamics of the UAV to linear state equations. Based on the assumption that the wind disturbance can be known precisely, an optimal control law is derived for the UAV''s 3D trajectory tracking using the LQR (Linear Quadratic Regulator). Then considering the unknown wind disturbance, a robust term is designed to replace the unknown wind disturbance, and a robust optimal control law is obtained. Global asymptotic stability of the closed-loop system is proved by Lyapunov stability theory. Simulations show that the proposed control law can achieve precise 3D UAV trajectory tracking with wind disturbance attenuation, and has good tracking performance.%该文提出一种未知风场扰动下无人机精确3维航路跟踪的鲁棒最优控制律.该控制律基于跟踪虚拟目标的思想,将风场扰动加入无人机运动方程,采用反馈线性化将无人机的非线性动力学方程变换为线性状态方程.假设风场扰动已知的条件下,采用线性二次型调节器推导出能够跟踪3维航路的最优控制律.进一步考虑未知的风场扰动,设计鲁棒控制项代替最优控制律中的风场参数,得到能够抑制未知有界风场干扰的鲁棒最优控制律,并采用Lyapunov稳定性理论证明该闭环系统的全局渐近稳定性.仿真表明该控制律能够实现在未知风场扰动下无人机精确3维航迹跟踪,且具有良好的跟踪性能.

  2. Large scale tracking algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Ross L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Love, Joshua Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Melgaard, David Kennett [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Karelitz, David B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pitts, Todd Alan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zollweg, Joshua David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Anderson, Dylan Z. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nandy, Prabal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Whitlow, Gary L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bender, Daniel A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Byrne, Raymond Harry [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-01-01

    Low signal-to-noise data processing algorithms for improved detection, tracking, discrimination and situational threat assessment are a key research challenge. As sensor technologies progress, the number of pixels will increase signi cantly. This will result in increased resolution, which could improve object discrimination, but unfortunately, will also result in a significant increase in the number of potential targets to track. Many tracking techniques, like multi-hypothesis trackers, suffer from a combinatorial explosion as the number of potential targets increase. As the resolution increases, the phenomenology applied towards detection algorithms also changes. For low resolution sensors, "blob" tracking is the norm. For higher resolution data, additional information may be employed in the detection and classfication steps. The most challenging scenarios are those where the targets cannot be fully resolved, yet must be tracked and distinguished for neighboring closely spaced objects. Tracking vehicles in an urban environment is an example of such a challenging scenario. This report evaluates several potential tracking algorithms for large-scale tracking in an urban environment.

  3. Large scale tracking algorithms.

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Ross L.; Love, Joshua Alan; Melgaard, David Kennett; Karelitz, David B.; Pitts, Todd Alan; Zollweg, Joshua David; Anderson, Dylan Z.; Nandy, Prabal; Whitlow, Gary L.; Bender, Daniel A.; Byrne, Raymond Harry

    2015-01-01

    Low signal-to-noise data processing algorithms for improved detection, tracking, discrimination and situational threat assessment are a key research challenge. As sensor technologies progress, the number of pixels will increase signi cantly. This will result in increased resolution, which could improve object discrimination, but unfortunately, will also result in a significant increase in the number of potential targets to track. Many tracking techniques, like multi-hypothesis trackers, suffer from a combinatorial explosion as the number of potential targets increase. As the resolution increases, the phenomenology applied towards detection algorithms also changes. For low resolution sensors, "blob" tracking is the norm. For higher resolution data, additional information may be employed in the detection and classfication steps. The most challenging scenarios are those where the targets cannot be fully resolved, yet must be tracked and distinguished for neighboring closely spaced objects. Tracking vehicles in an urban environment is an example of such a challenging scenario. This report evaluates several potential tracking algorithms for large-scale tracking in an urban environment.

  4. Generative models for pedestrian track analysis

    NARCIS (Netherlands)

    Kooij, J.F.P.

    2015-01-01

    Various problems in tracking and track analysis are addressed, with a focus on applications in the surveillance and intelligent vehicle domains, such as pedestrian path prediction, learning spatial and temporal structure of behavior patterns in data, anomalous track detection, and data association w

  5. Generative models for pedestrian track analysis

    NARCIS (Netherlands)

    Kooij, J.F.P.

    2015-01-01

    Various problems in tracking and track analysis are addressed, with a focus on applications in the surveillance and intelligent vehicle domains, such as pedestrian path prediction, learning spatial and temporal structure of behavior patterns in data, anomalous track detection, and data association

  6. Influence of dynamic stiffness of primary suspension on vehicle-track coupled vibration%一系螺旋弹簧动刚度对车辆-轨道耦合振动影响分析

    Institute of Scientific and Technical Information of China (English)

    孙文静; 宫岛; 周劲松; 李卓

    2015-01-01

    The dynamic model of helical spring in axle box of primary suspension,which can be solved by using dynamic stiffness matrix method,was established to get its dynamic stiffness for studying the effect of waves propagating in helical spring on the vibration isolation performance of primary suspension.Then,the dynamic stiffness characteristics were introduced into the vehicle-track coupled dynamic model which was then solved with Green's function method for comparing the dynamic performances between the models with constant stiffness and dynamic stiffness.The results show that the frequency-dependent stiffness can be calculated efficiently with the dynamic stiffness matrix method and the spring stiffness has a thousand-flod dramatic change at the frequency higher than the first modal frequency.This conclusion was verified with the finite element method.This change led to high vibration displacement transmission rate from wheel to bogie at high frequencies,it was shown that it is nearly equal to 1,while the tramission rate from wheel to car body is about 10 -3 .There are lots of vibration peaks at high frequencies on car body and bogie in vehicle-track coupled dynamic simulation,which are much stronger than those on wheel or rail;the vehicle model including dynamic stiffness of primary suspension spring is more realistic;in order to reduce vehicle vibration,the modal frequency of spring should be raised and the varying of dynamic stiffness amplitude should be as small as possible.%建立准确表征一系悬挂轴箱螺旋弹簧波动特性的力学模型,运用动刚度矩阵法求解,研究其对悬挂系统隔振性能影响。结合基于格林函数法的车辆-轨道耦合动力学模型,引入弹簧刚度频变特性,对比分析考虑一系螺旋弹簧频变刚度前后车辆动力学性能之间的差异。结果表明,动刚度矩阵法可以精确求解螺旋弹簧随频率变化的动刚度特性,在一阶模态振动

  7. An Enhanced Satellite-Based Algorithm for Detecting and Tracking Dust Outbreaks by Means of SEVIRI Data

    Directory of Open Access Journals (Sweden)

    Francesco Marchese

    2017-05-01

    Full Text Available Dust outbreaks are meteorological phenomena of great interest for scientists and authorities (because of their impact on the climate, environment, and human activities, which may be detected, monitored, and characterized from space using different methods and procedures. Among the recent dust detection algorithms, the RSTDUST multi-temporal technique has provided good results in different geographic areas (e.g., Mediterranean basin; Arabian Peninsula, exhibiting a better performance than traditional split window methods, in spite of some limitations. In this study, we present an optimized configuration of this technique, which better exploits data provided by Spinning Enhanced Visible and Infrared Imager (SEVIRI aboard Meteosat Second Generation (MSG satellites to address those issues (e.g., sensitivity reduction over arid and semi-arid regions; dependence on some meteorological clouds. Three massive dust events affecting Europe and the Mediterranean basin in May 2008/2010 are analysed in this work, using information provided by some independent and well-established aerosol products to assess the achieved results. The study shows that the proposed algorithm, christened eRSTDUST (i.e., enhanced RSTDUST, which provides qualitative information about dust outbreaks, is capable of increasing the trade-off between reliability and sensitivity. The results encourage further experimentations of this method in other periods of the year, also exploiting data provided by different satellite sensors, for better evaluating the advantages arising from the use of this dust detection technique in operational scenarios.

  8. Vehicle to Vehicle Services

    DEFF Research Database (Denmark)

    Brønsted, Jeppe Rørbæk

    2008-01-01

    , mobility, and availability of services. The dissertation consists of two parts. Part I gives an overview of service oriented architecture for pervasive computing systems and describes the contributions of the publications listed in part II. We investigate architecture for vehicular technology applications......As computing devices, sensors, and actuators pervade our surroundings, new applications emerge with accompanying research challenges. In the transportation domain vehicles are being linked by wireless communication and equipped with an array of sensors and actuators that make is possible to provide...... location aware infotainment, increase safety, and lessen environmental strain. This dissertation is about service oriented architecture for pervasive computing with an emphasis on vehicle to vehicle applications. If devices are exposed as services, applications can be created by composing a set of services...

  9. Advanced Vehicle Testing and Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Garetson, Thomas [The Clarity Group, Incorporated, Chicago, IL (United States)

    2013-03-31

    The objective of the United States (U.S.) Department of Energy's (DOEs) Advanced Vehicle Testing and Evaluation (AVTE) project was to provide test and evaluation services for advanced technology vehicles, to establish a performance baseline, to determine vehicle reliability, and to evaluate vehicle operating costs in fleet operations.Vehicles tested include light and medium-duty vehicles in conventional, hybrid, and all-electric configurations using conventional and alternative fuels, including hydrogen in internal combustion engines. Vehicles were tested on closed tracks and chassis dynamometers, as well as operated on public roads, in fleet operations, and over prescribed routes. All testing was controlled by procedures developed specifically to support such testing.

  10. Advanced Vehicle Testing and Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Garetson, Thomas [The Clarity Group, Incorporated, Chicago, IL (United States)

    2013-03-31

    The objective of the United States (U.S.) Department of Energy's (DOEs) Advanced Vehicle Testing and Evaluation (AVTE) project was to provide test and evaluation services for advanced technology vehicles, to establish a performance baseline, to determine vehicle reliability, and to evaluate vehicle operating costs in fleet operations.Vehicles tested include light and medium-duty vehicles in conventional, hybrid, and all-electric configurations using conventional and alternative fuels, including hydrogen in internal combustion engines. Vehicles were tested on closed tracks and chassis dynamometers, as well as operated on public roads, in fleet operations, and over prescribed routes. All testing was controlled by procedures developed specifically to support such testing.

  11. Persistent Aerial Tracking

    KAUST Repository

    Mueller, Matthias

    2016-04-13

    In this thesis, we propose a new aerial video dataset and benchmark for low altitude UAV target tracking, as well as, a photo-realistic UAV simulator that can be coupled with tracking methods. Our benchmark provides the rst evaluation of many state of-the-art and popular trackers on 123 new and fully annotated HD video sequences captured from a low-altitude aerial perspective. Among the compared trackers, we determine which ones are the most suitable for UAV tracking both in terms of tracking accuracy and run-time. We also present a simulator that can be used to evaluate tracking algorithms in real-time scenarios before they are deployed on a UAV "in the field", as well as, generate synthetic but photo-realistic tracking datasets with free ground truth annotations to easily extend existing real-world datasets. Both the benchmark and simulator will be made publicly available to the vision community to further research in the area of object tracking from UAVs. Additionally, we propose a persistent, robust and autonomous object tracking system for unmanned aerial vehicles (UAVs) called Persistent Aerial Tracking (PAT). A computer vision and control strategy is applied to a diverse set of moving objects (e.g. humans, animals, cars, boats, etc.) integrating multiple UAVs with a stabilized RGB camera. A novel strategy is employed to successfully track objects over a long period, by \\'handing over the camera\\' from one UAV to another. We integrate the complete system into an off-the-shelf UAV, and obtain promising results showing the robustness of our solution in real-world aerial scenarios.

  12. 新型竖向载荷布置方式下的低地板轻轨车辆曲线通过能力分析%Analysis of the Pass Ability of New Type Structure Low-floor Vehicles on Curved Track

    Institute of Scientific and Technical Information of China (English)

    王鹏博; 沈钢; 李学良

    2013-01-01

    A new structure of low-floor vehicle proposed on the basis of the original low-floor vehicles' characteristics is presented. The response of the new low-floor vehicles on curved track is analyzed by establishing a dynamic simulation model. Compared with the results of the simulation model of a traditional low-floor vehicle, it confirms that the contact arrangement of the gravity of car-body center and bogie center can improve the responses of low-floor vehicles on curved track.%根据低地板轻轨车辆受力特点,提出新型的车辆结构布置方式,建立动力学仿真模型分析新型低地板车辆的曲线通过能力.与传统低地板车辆模型仿真结果进行比较,证实了采用车体重心与转向架中心重合的布置方式有利于提高低地板车辆的曲线通过能力.

  13. Differences in estimating terrestrial water flux from three satellite-based Priestley-Taylor algorithms

    Science.gov (United States)

    Yao, Yunjun; Liang, Shunlin; Yu, Jian; Zhao, Shaohua; Lin, Yi; Jia, Kun; Zhang, Xiaotong; Cheng, Jie; Xie, Xianhong; Sun, Liang; Wang, Xuanyu; Zhang, Lilin

    2017-04-01

    Accurate estimates of terrestrial latent heat of evaporation (LE) for different biomes are essential to assess energy, water and carbon cycles. Different satellite- based Priestley-Taylor (PT) algorithms have been developed to estimate LE in different biomes. However, there are still large uncertainties in LE estimates for different PT algorithms. In this study, we evaluated differences in estimating terrestrial water flux in different biomes from three satellite-based PT algorithms using ground-observed data from eight eddy covariance (EC) flux towers of China. The results reveal that large differences in daily LE estimates exist based on EC measurements using three PT algorithms among eight ecosystem types. At the forest (CBS) site, all algorithms demonstrate high performance with low root mean square error (RMSE) (less than 16 W/m2) and high squared correlation coefficient (R2) (more than 0.9). At the village (HHV) site, the ATI-PT algorithm has the lowest RMSE (13.9 W/m2), with bias of 2.7 W/m2 and R2 of 0.66. At the irrigated crop (HHM) site, almost all models algorithms underestimate LE, indicating these algorithms may not capture wet soil evaporation by parameterization of the soil moisture. In contrast, the SM-PT algorithm shows high values of R2 (comparable to those of ATI-PT and VPD-PT) at most other (grass, wetland, desert and Gobi) biomes. There are no obvious differences in seasonal LE estimation using MODIS NDVI and LAI at most sites. However, all meteorological or satellite-based water-related parameters used in the PT algorithm have uncertainties for optimizing water constraints. This analysis highlights the need to improve PT algorithms with regard to water constraints.

  14. Characterization of satellite based proxies for estimating nucleation mode particles over South Africa

    Directory of Open Access Journals (Sweden)

    A.-M. Sundström

    2014-10-01

    Full Text Available In this work satellite observations from the NASA's A-Train constellation were used to derive the values of primary emission and regional nucleation proxies over South Africa to estimate the potential for new particle formation. As derived in Kulmala et al. (2011, the satellite based proxies consist of source terms (NO2, SO2 and UV-B radiation, and a sink term describing the pre-existing aerosols. The first goal of this work was to study in detail the use of satellite aerosol optical depth (AOD as a substitute to the in situ based condensation sink (CS. One of the major factors affecting the agreement of CS and AOD was the elevated aerosol layers that increased the value of column integrated AOD but not affected the in situ CS. However, when the AOD in the proxy sink was replaced by an estimate from linear bivariate fit between AOD and CS, the agreement with the actual nucleation mode number concentration improved somewhat. The second goal of the work was to estimate how well the satellite based proxies can predict the potential for new particle formation. For each proxy the highest potential for new particle formation were observed over the Highveld industrial area, where the emissions were high but the sink due to pre-existing aerosols was relatively low. Best agreement between the satellite and in situ based proxies were obtained for NO2/AOD and UV-B/AOD2, whereas proxies including SO2 in the source term had lower correlation. Even though the OMI SO2 boundary layer product showed reasonable spatial pattern and detected the major sources over the study area, some of the known minor point sources were not detected. When defining the satellite proxies only for days when new particle formation event was observed, it was seen that for all the satellite based proxies the event day medians were higher than the entire measurement period median.

  15. GNSS Hardware-In-The-Loop Formation and Tracking Control

    OpenAIRE

    2016-01-01

    Formation and tracking control are critical for of today's vehicle applications in and this will be true for future vehicle technologies as well. Although the general function of these controls is for data collection and military applications, formation and tracking control may be applied to automobiles, drones, submarines, and spacecraft. The primary application here is the investigation of formation keeping and tracking solutions for realistic, real-time, and multi-vehicle simulations. This...

  16. 基于车-地通信的朔黄铁路列车追踪优化研究%Research on Train Tracking Optimization of Shuo-Huang Railway Based on Vehicle-to-round Communication

    Institute of Scientific and Technical Information of China (English)

    孙永生

    2016-01-01

    为优化朔黄铁路列车追踪,通过增加地面调度优化系统和车载辅助智能操控系统,建立基于LTE-R网络的连续车-地通信,使车载设备获得更多的前方线路信息,并实时监督列车的追踪间隔,从而实现列车精确定位以及临时限速和行车许可即时传递,通过比对分析,优化后不仅能提高效益,更能保证列车运行安全。%To optimize the train tracking on Shuo-Huang railway, LTE-R-network-based continuous vehicle-to-ground communication is established by adding more ground optimized dispatching and on-board intelligent auxiliary control system to get more information of the line ahead and monitor train intervals in real-time. Thus, precision train location is achieved and temporary speed limit and traffic permit are delivered immediately. With comparison and analysis, the optimization can not only improve the efficiency, but also ensure the safety of the train operation.

  17. Evaluation of Clear Sky Models for Satellite-Based Irradiance Estimates

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, M.; Gotseff, P.

    2013-12-01

    This report describes an intercomparison of three popular broadband clear sky solar irradiance model results with measured data, as well as satellite-based model clear sky results compared to measured clear sky data. The authors conclude that one of the popular clear sky models (the Bird clear sky model developed by Richard Bird and Roland Hulstrom) could serve as a more accurate replacement for current satellite-model clear sky estimations. Additionally, the analysis of the model results with respect to model input parameters indicates that rather than climatological, annual, or monthly mean input data, higher-time-resolution input parameters improve the general clear sky model performance.

  18. Analysis of Performance of Jerk Models in Tracking High Speed Maneuvering Vehicles%Jerk模型用于高速机动飞行器跟踪的性能分析

    Institute of Scientific and Technical Information of China (English)

    梁小虎; 朱武宣; 郭军海; 赵华

    2013-01-01

    A review is given on four Jerk models for tracking HSMV (High Speed Maneuvering Vehicles),namely,SJ (Singer Jerk),CSJ (Current Statistic Jerk),MCSJ (Modified Current Statistic Jerk) and αJ.Their modeling hypotheses,designed parameters and constraints in real applications are compared.Based on UKF (Unscented Kalman Filter) algorithm,tracking simulation is performed for near space high speed gliding vehicles using the four models under single-radar and dual-radar measurement conditions and with three filtering parameter sets.The real trajectory is generated by solving simplified dynamics formula using Runge-Kutta method.Simulation results show that all four jerk models have good robustness in filter initial value and good robustness for model parameters in weak maneuvering course.In strong maneuvering course,SJ,CSJ and MCSJ models have poor robustness and the estimate errors increase sharply while αJ has good robustness.To track HSMV,αJ has the best comprehensive performance while MCSJ is the worst one.%针对高速机动飞行器的跟踪应用,对SJ (Singer Jerk)、CSJ(当前统计Jerk)、MCSJ(修正当前统计Jerk)和αJ等4种主要Jerk模型进行了综述.比较了它们的建模假设、设计参数以及实际应用时的限制因素.基于UKF(无迹卡尔曼滤波)算法,分别在单台和2台雷达的测量条件下,在3种滤波参数集设置下,利用各模型对近空高速滑翔飞行器进行了跟踪仿真.飞行器真实飞行轨迹根据简化动力学方程通过四阶龙格库塔数值积分方法得到.仿真结果表明:4种模型都具有很好的初值鲁棒性;在目标弱机动段落,4种模型具有较好的参数鲁棒性;但在强机动段落,SJ、CSJ、MCSJ等3种模型的参数鲁棒性很差,滤波误差发生严重突跳,αJ模型的参数鲁棒性最好.针对高速机动飞行器的跟踪应用,αJ模型的综合性能最优,而MCSJ模型最差.

  19. 76 FR 51120 - Denial of Motor Vehicle Defect Petition

    Science.gov (United States)

    2011-08-17

    ... National Highway Traffic Safety Administration Denial of Motor Vehicle Defect Petition AGENCY: National Highway Traffic Safety Administration (NHTSA), Department of Transportation. ACTION: Denial of motor... System (FARS) tracks all fatal crashes involving motor vehicles in the United States. An analysis...

  20. Tropic Testing of Vehicles

    Science.gov (United States)

    2014-08-27

    kilometer track running through tropical forest . The track is a combination of a bauxite/dirt base with grades on the road up to 20 percent and log...TYPE Final 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Test Operations Procedure (TOP) 02-2-817A Tropic Testing of Vehicles 5a...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) U.S. Army Yuma Proving Ground Tropic Regions Test Center (TEDT-YPT) 301 C. Street Yuma, AZ

  1. Simultaneous ground- and satellite-based observation of MF/HF auroral radio emissions

    Science.gov (United States)

    Sato, Yuka; Kumamoto, Atsushi; Katoh, Yuto; Shinbori, Atsuki; Kadokura, Akira; Ogawa, Yasunobu

    2016-05-01

    We report on the first simultaneous measurements of medium-high frequency (MF/HF) auroral radio emissions (above 1 MHz) by ground- and satellite-based instruments. Observational data were obtained by the ground-based passive receivers in Iceland and Svalbard, and by the Plasma Waves and Sounder experiment (PWS) mounted on the Akebono satellite. We observed two simultaneous appearance events, during which the frequencies of the auroral roar and MF bursts detected at ground level were different from those of the terrestrial hectometric radiation (THR) observed by the Akebono satellite passing over the ground-based stations. This frequency difference confirms that auroral roar and THR are generated at different altitudes across the F peak. We did not observe any simultaneous observations that indicated an identical generation region of auroral roar and THR. In most cases, MF/HF auroral radio emissions were observed only by the ground-based detector, or by the satellite-based detector, even when the satellite was passing directly over the ground-based stations. A higher detection rate was observed from space than from ground level. This can primarily be explained in terms of the idea that the Akebono satellite can detect THR emissions coming from a wider region, and because a considerable portion of auroral radio emissions generated in the bottomside F region are masked by ionospheric absorption and screening in the D/E regions associated with ionization which results from auroral electrons and solar UV radiation.

  2. Eliminating Obliquity Error from the Estimation of Ionospheric Delay in a Satellite-Based Augmentation System

    Science.gov (United States)

    Sparks, Lawrence

    2013-01-01

    Current satellite-based augmentation systems estimate ionospheric delay using algorithms that assume the electron density of the ionosphere is non-negligible only in a thin shell located near the peak of the actual profile. In its initial operating capability, for example, the Wide Area Augmentation System incorporated the thin shell model into an estimation algorithm that calculates vertical delay using a planar fit. Under disturbed conditions or at low latitude where ionospheric structure is complex, however, the thin shell approximation can serve as a significant source of estimation error. A recent upgrade of the system replaced the planar fit algorithm with an algorithm based upon kriging. The upgrade owes its success, in part, to the ability of kriging to mitigate the error due to this approximation. Previously, alternative delay estimation algorithms have been proposed that eliminate the need for invoking the thin shell model altogether. Prior analyses have compared the accuracy achieved by these methods to the accuracy achieved by the planar fit algorithm. This paper extends these analyses to include a comparison with the accuracy achieved by kriging. It concludes by examining how a satellite-based augmentation system might be implemented without recourse to the thin shell approximation.

  3. Development of satellite-based drought monitoring and warning system in Asian Pacific countries

    Science.gov (United States)

    Takeuchi, W.; Oyoshi, K.; Muraki, Y.

    2013-12-01

    This research focuses on a development of satellite-based drought monitoring warning system in Asian Pacific countries. Drought condition of cropland is evaluated by using Keeth-Byram Drought Index (KBDI) computed from rainfall measurements with GSMaP product, land surface temperature by MTSAT product and vegetation phenology by MODIS NDVI product at daily basis. The derived information is disseminated as a system for an application of space based technology (SBT) in the implementation of the Core Agriculture Support Program. The benefit of this system are to develop satellite-based drought monitoring and early warning system (DMEWS) for Asian Pacific counties using freely available data, and to develop capacity of policy makers in those countries to apply the developed system in policy making. A series of training program has been carried out in 2013 to officers and researchers of ministry of agriculture and relevant agencies in Greater Mekong Subregion countries including Cambodia, China, Myanmar, Laos, Thailand and Vietnam. This system is running as fully operational and can be accessed at http://webgms.iis.u-tokyo.ac.jp/DMEWS/.

  4. Intelligent Vehicle Health Management

    Science.gov (United States)

    Paris, Deidre E.; Trevino, Luis; Watson, Michael D.

    2005-01-01

    objectives: Guidance and Navigation; Communications and Tracking; Vehicle Monitoring; Information Transport and Integration; Vehicle Diagnostics; Vehicle Prognostics; Vehicle mission Planning; Automated Repair and Replacement; Vehicle Control; Human Computer Interface; and Onboard Verification and Validation. Furthermore, the presented framework provides complete vehicle management which not only allows for increased crew safety and mission success through new intelligence capabilities, but also yields a mechanism for more efficient vehicle operations. The representative IVHM technologies for computer platform using heterogeneous communication, 3) coupled electromagnetic oscillators for enhanced communications, 4) Linux-based real-time systems, 5) genetic algorithms, 6) Bayesian Networks, 7) evolutionary algorithms, 8) dynamic systems control modeling, and 9) advanced sensing capabilities. This paper presents IVHM technologies developed under NASA's NFFP pilot project and the integration of these technologies forms the framework for IIVM.

  5. Video surveillance of pedestrians and vehicles

    Science.gov (United States)

    Gutchess, Daniel; Ablavsky, Vitaly; Thangali, Ashwin; Sclaroff, Stan; Snorrason, Magnús

    2007-04-01

    In this paper, we focus on the problem of automated surveillance in a parking lot scenario. We call our research system VANESSA, for Video Analysis for Nighttime Surveillance and Situational Awareness. VANESSA is capable of: 1) detecting moving objects via background modeling and false motion suppression, 2) tracking and classifying pedestrians and vehicles, and 3) detecting events such as person entering or exiting a vehicle. Moving object detection utilizes a multi-stage cascading approach to identify pixels that belong to the true objects and reject any spurious motion, (e.g., due to vehicle headlights or moving foliage). Pedestrians and vehicles are tracked using a multiple hypothesis tracker coupled with a particle filter for state estimation and prediction. The space-time trajectory of each tracked object is stored in an SQL database along with sample imagery to support video forensics applications. The detection of pedestrians entering/exiting vehicles is accomplished by first estimating the three-dimensional pose and the corresponding entry and exit points of each tracked vehicle in the scene. A pedestrian activity model is then used to probabilistically assign pedestrian tracks that appear or disappear in the vicinity of these entry/exit points. We evaluate the performance of tracking and pedestrian-vehicle association on an extensive data set collected in a challenging real-world scenario.

  6. Assessing the performance of satellite-based precipitation products over the Mediterranean region

    Science.gov (United States)

    Xaver, Angelika; Dorigo, Wouter; Brocca, Luca; Ciabatta, Luca

    2017-04-01

    Detailed knowledge about the spatial and temporal patterns and quantities of precipitation is of high importance. This applies especially in the Mediterranean region, where water demand for agricultural, industrial and touristic needs is growing and climate projections foresee a decrease of precipitation amounts and an increase in variability. In this region, ground-based rain gauges are available only limited in number, particularly in northern Africa and the Middle East and lack to capture the high spatio-temporal character of precipitation over large areas. This has motivated the development of a large number of remote sensing products for monitoring rainfall. Satellite-based precipitation products are based on various observation principles and retrieval approaches, i.e. from thermal infra-red and microwaves. Although, many individual validation studies on the performance of these precipitation datasets exist, they mostly examine only one or a few of these rainfall products at the same time and are not targeted at the Mediterranean basin as a whole. Here, we present an extensive comparative study of seven different satellite-based precipitation products, namely CMORPH 30-minutes, CMORPH 3-hourly, GPCP, PERSIANN, SM2Rain CCI, TRMM TMPA 3B42, and TRMM TMPA 3B42RT, focusing on the whole Mediterranean region and on individual Mediterranean catchments. The time frame of investigation is restricted by the common availability of all precipitation products and covers the period 2000-2013. We assess the skill of the satellite products against gridded gauge-based data provided by GPCC and E-OBS. Apart from common characteristics like biases and temporal correlations we evaluate several sophisticated dataset properties that are of particular interest for Mediterranean hydrology, including the capability of the remotely sensed products to capture extreme events and trends. A clear seasonal dependency of the correlation results can be observed for the whole Mediterranean

  7. Bias reduction for Satellite Based Precipitation Estimates using statistical transformations in Guiana Shield

    Science.gov (United States)

    Ringard, Justine; Becker, Melanie; Seyler, Frederique; Linguet, Laurent

    2016-04-01

    Currently satellite-based precipitation estimates exhibit considerable biases, and there have been many efforts to reduce these biases by merging surface gauge measurements with satellite-based estimates. In Guiana Shield all products exhibited better performances during the dry season (August- December). All products greatly overestimate very low intensities (50 mm). Moreover the responses of each product are different according to hydro climatic regimes. The aim of this study is to correct spatially the bias of precipitation, and compare various correction methods to define the best methods depending on the rainfall characteristic correcting (intensity, frequency). Four satellites products are used: Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) research product (3B42V7) and real time product (3B42RT), the Precipitation Estimation from Remotely-Sensed Information using Artificial Neural Network (PERSIANN) and the NOAA Climate Prediction Center (CPC) Morphing technique (CMORPH), for six hydro climatic regimes between 2001 and 2012. Several statistical transformations are used to correct the bias. Statistical transformations attempt to find a function h that maps a simulated variable Ps such that its new distribution equals the distribution of the observed variable Po. The first is the use of a distribution derived transformations which is a mixture of the Bernoulli and the Gamma distribution, where the Bernoulli distribution is used to model the probability of precipitation occurrence and the Gamma distribution used to model precipitation intensities. The second a quantile-quantile relation using parametric transformation, and the last one is a common approach using the empirical CDF of observed and modelled values instead of assuming parametric distributions. For each correction 30% of both, simulated and observed data sets, are used to calibrate and the other part used to validate. The validation are test with statistical

  8. Research on the Damage Characteristics of Double-Block Ballastless Track Bed Slab under Temperature and Vehicle Dynamic Loads%温度和列车动荷载作用下双块式无砟轨道道床板损伤特性研究

    Institute of Scientific and Technical Information of China (English)

    朱胜阳; 蔡成标

    2012-01-01

    采用混凝土损伤塑性模型描述双块式无砟轨道道床板的力学行为,以变温作用下道床板最大损伤状态作为初始条件、车辆—双块式轨道耦合动力分析得到的各钢轨支点压力作为轨道路基的外部激励,进行变温和列车动荷载共同作用下道床板损伤的演变规律及道床板损伤对结构受力影响的研究.结果表明:在降温过程中道床板会发生横向弯曲变形,产生损伤,导致受拉承载力下降;在升温过程中由于降温导致的道床板拉伸损伤不可恢复,所以道床板损伤值不变,最终保持在0.23左右,但刚度出现恢复现象;车辆经过已损伤的道床板时,道床板内部裂纹交替张开与闭合,刚度出现短暂的部分恢复阶段,刚度退化系数最大幅值为0.057,而道床板损伤值不变,且道床板的位移和加速度幅值、支承层与基床表面的动应力幅值均比无损伤时增大,拉应力幅值减小;损伤塑性模型能很好地反映道床板混凝土的软化及刚度退化行为.%The concrete damaged plasticity model was adopted to describe the mechanical characteristics of double-block ballastless track bed slab. Setting the maximum damaged state of track bed slab under changing temperature as the initial condition and taking the rail supporting force obtained by vehicle-double-block ballastless track coupled dynamic simulation as an external excitation of track-subgrade structures, the damage evolution law of track bed slab and the influence of track bed slab on the mechanical behavior of structure were analyzed under the joint action of changing temperature and vehicle dynamic load. Results show that the track bed slab presents lateral bending deformation and produces damage which weakens the tensile capacity in temperature dropping process. While in the temperature rising process, the damage value of track bed slab remains unchanged and keeps around 0. 23 due to the tension damage produced by

  9. Engineering satellite-based navigation and timing global navigation satellite systems, signals, and receivers

    CERN Document Server

    Betz, J

    2016-01-01

    This book describes the design and performance analysis of satnav systems, signals, and receivers. It also provides succinct descriptions and comparisons of all the world’s satnav systems. Its comprehensive and logical structure addresses all satnav signals and systems in operation and being developed. Engineering Satellite-Based Navigation and Timing: Global Navigation Satellite Systems, Signals, and Receivers provides the technical foundation for designing and analyzing satnav signals, systems, and receivers. Its contents and structure address all satnav systems and signals: legacy, modernized, and new. It combines qualitative information with detailed techniques and analyses, providing a comprehensive set of insights and engineering tools for this complex multidisciplinary field. Part I describes system and signal engineering including orbital mechanics and constellation design, signal design principles and underlying considerations, link budgets, qua tifying receiver performance in interference, and e...

  10. Satellite-based detection of volcanic sulphur dioxide from recent eruptions in Central and South America

    Directory of Open Access Journals (Sweden)

    D. Loyola

    2008-01-01

    Full Text Available Volcanic eruptions can emit large amounts of rock fragments and fine particles (ash into the atmosphere, as well as several gases, including sulphur dioxide (SO2. These ejecta and emissions are a major natural hazard, not only to the local population, but also to the infrastructure in the vicinity of volcanoes and to aviation. Here, we describe a methodology to retrieve quantitative information about volcanic SO2 plumes from satellite-borne measurements in the UV/Visible spectral range. The combination of a satellite-based SO2 detection scheme and a state-of-the-art 3D trajectory model enables us to confirm the volcanic origin of trace gas signals and to estimate the plume height and the effective emission height. This is demonstrated by case-studies for four selected volcanic eruptions in South and Central America, using the GOME, SCIAMACHY and GOME-2 instruments.

  11. Estimating crop yield using a satellite-based light use efficiency model

    DEFF Research Database (Denmark)

    Yuan, Wenping; Chen, Yang; Xia, Jiangzhou

    2016-01-01

    for simulating crops’ GPP. At both irrigated and rainfed sites, the EC-LUE model exhibits a similar level of performance. However, large errors are found when simulating yield based on crop harvest index. This analysis highlights the need to improve the representation of the harvest index and carbon allocation...... primary production (GPP) and yield of crops. The EC-LUE model can explain on average approximately 90% of the variability in GPP for 36 FLUXNET sites globally. The results indicate that a universal set of parameters, independent of crop species (except for C4 crops), can be adopted in the EC-LUE model...... for improving crop yield estimations from satellite-based methods....

  12. Trellis coding with Continuous Phase Modulation (CPM) for satellite-based land-mobile communications

    Science.gov (United States)

    1989-01-01

    This volume of the final report summarizes the results of our studies on the satellite-based mobile communications project. It includes: a detailed analysis, design, and simulations of trellis coded, full/partial response CPM signals with/without interleaving over various Rician fading channels; analysis and simulation of computational cutoff rates for coherent, noncoherent, and differential detection of CPM signals; optimization of the complete transmission system; analysis and simulation of power spectrum of the CPM signals; design and development of a class of Doppler frequency shift estimators; design and development of a symbol timing recovery circuit; and breadboard implementation of the transmission system. Studies prove the suitability of the CPM system for mobile communications.

  13. DIGITAL VIDEO BROADCAST RETURN CHANNEL VIA SATELLITE (DVB-RCS HUB FOR SATELLITE BASED E-LEARNING

    Directory of Open Access Journals (Sweden)

    N.G.Vasantha Kumar

    2011-02-01

    Full Text Available This paper discusses in-house designed and developed scale-down DVB-RCS hub along with the performance of the realized hub. This development is intended to support the Satellite Based e-Learning initiative in India. The scale-down DVB-RCS HUB is implemented around a single PC with other subsystems making it very cost effective and unique of its kind. This realization will drastically reduce the total cost of Satellite based Education Networks as very low cost commercially available Satellite Interactive Terminals (SITs complying to open standard could be used at remote locations. The system is successfully tested to work with a commercial SIT using a GEO satellite EDUSAT which is especially dedicated for satellite based e-Learning. The internal detail of the DVB-RCS Forward and Return Link Organization and how it manages the Satellite Interactive Terminals access to the satellite channel using MF-TDMA approach has been described.

  14. Developing an improved soil moisture dataset by blending passive and active microwave satellite-based retrievals

    Directory of Open Access Journals (Sweden)

    Y. Y. Liu

    2011-02-01

    Full Text Available Combining information derived from satellite-based passive and active microwave sensors has the potential to offer improved estimates of surface soil moisture at global scale. We develop and evaluate a methodology that takes advantage of the retrieval characteristics of passive (AMSR-E and active (ASCAT microwave satellite estimates to produce an improved soil moisture product. First, volumetric soil water content (m3 m−3 from AMSR-E and degree of saturation (% from ASCAT are rescaled against a reference land surface model data set using a cumulative distribution function matching approach. While this imposes any bias of the reference on the rescaled satellite products, it adjusts them to the same range and preserves the dynamics of original satellite-based products. Comparison with in situ measurements demonstrates that where the correlation coefficient between rescaled AMSR-E and ASCAT is greater than 0.65 ("transitional regions", merging the different satellite products increases the number of observations while minimally changing the accuracy of soil moisture retrievals. These transitional regions also delineate the boundary between sparsely and moderately vegetated regions where rescaled AMSR-E and ASCAT, respectively, are used for the merged product. Therefore the merged product carries the advantages of better spatial coverage overall and increased number of observations, particularly for the transitional regions. The combination method developed has the potential to be applied to existing microwave satellites as well as to new missions. Accordingly, a long-term global soil moisture dataset can be developed and extended, enhancing basic understanding of the role of soil moisture in the water, energy and carbon cycles.

  15. Advancing land surface model development with satellite-based Earth observations

    Science.gov (United States)

    Orth, Rene; Dutra, Emanuel; Trigo, Isabel F.; Balsamo, Gianpaolo

    2017-04-01

    The land surface forms an essential part of the climate system. It interacts with the atmosphere through the exchange of water and energy and hence influences weather and climate, as well as their predictability. Correspondingly, the land surface model (LSM) is an essential part of any weather forecasting system. LSMs rely on partly poorly constrained parameters, due to sparse land surface observations. With the use of newly available land surface temperature observations, we show in this study that novel satellite-derived datasets help to improve LSM configuration, and hence can contribute to improved weather predictability. We use the Hydrology Tiled ECMWF Scheme of Surface Exchanges over Land (HTESSEL) and validate it comprehensively against an array of Earth observation reference datasets, including the new land surface temperature product. This reveals satisfactory model performance in terms of hydrology, but poor performance in terms of land surface temperature. This is due to inconsistencies of process representations in the model as identified from an analysis of perturbed parameter simulations. We show that HTESSEL can be more robustly calibrated with multiple instead of single reference datasets as this mitigates the impact of the structural inconsistencies. Finally, performing coupled global weather forecasts we find that a more robust calibration of HTESSEL also contributes to improved weather forecast skills. In summary, new satellite-based Earth observations are shown to enhance the multi-dataset calibration of LSMs, thereby improving the representation of insufficiently captured processes, advancing weather predictability and understanding of climate system feedbacks. Orth, R., E. Dutra, I. F. Trigo, and G. Balsamo (2016): Advancing land surface model development with satellite-based Earth observations. Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-628

  16. Evaluation of satellite-based precipitation estimates in winter season using an object-based approach

    Science.gov (United States)

    Li, J.; Hsu, K.; AghaKouchak, A.; Sorooshian, S.

    2012-12-01

    Verification has become an integral component of satellite precipitation algorithms and products. A number of object-based verification methods have been proposed to provide diagnostic information regarding the precipitation products' ability to capture the spatial pattern, intensity, and placement of precipitation. However, most object-based methods are not capable of investigating precipitation objects at the storm-scale. In this study, an image processing approach known as watershed segmentation was adopted to detect the storm-scale rainfall objects. Then, a fuzzy logic-based technique was utilized to diagnose and analyze storm-scale object attributes, including centroid distance, area ratio, intersection area ratio and orientation angle difference. Three verification metrics (i.e., false alarm ratio, missing ratio and overall membership score) were generated for validation and verification. Three satellite-based precipitation products, including PERSIANN, CMORPH, 3B42RT, were evaluated against NOAA stage IV MPE multi-sensor composite rain analysis at 0.25° by 0.25° on a daily scale in the winter season of 2010 over the contiguous United States. Winter season is dominated by frontal systems which usually have larger area coverage. All three products and the stage IV observation tend to find large size storm objects. With respect to the evaluation attributes, PERSIANN tends to obtain larger area ratio and consequently has larger centroid distance to the stage IV observations, while 3B42RT are found to be closer to the stage IV for the object size. All evaluation products give small orientation angle differences but vary significantly for the missing ratio and false alarm ratio. This implies that satellite estimates can fail to detect storms in winter. The overall membership scores are close for all three different products which indicate that all three satellite-based precipitation products perform well for capturing the spatial and geometric characteristics of

  17. Validation of the Global NASA Satellite-based Flood Detection System in Bangladesh

    Science.gov (United States)

    Moffitt, C. B.

    2009-12-01

    Floods are one of the most destructive natural forces on earth, affecting millions of people annually. Nations lying in the downstream end of an international river basin often suffer the most damage during flooding and could benefit from the real-time communication of rainfall and stream flow data from countries upstream. This is less likely to happen among developing nations due to a lack of freshwater treaties (Balthrop and Hossain, Water Policy, 2009). A more viable option is for flood-prone developing nations to utilize the global satellite rainfall and modeled runoff data that is independently and freely available from the NASA Satellite-based Global Flood Detection System. Although the NASA Global Flood Detection System has been in operation in real-time since 2006, the ‘detection’ capability of flooding has only been validated against qualitative reports in news papers and other types of media. In this study, a more quantitative validation against in-situ measurements of the flood detection system over Bangladesh is presented. Using ground-measured stream flow data as well as satellite-based flood potential and rainfall data, the study looks into the relationship between rainfall and flood potential, rainfall and stream flow, and stream flow and flood potential for three very distinct river systems in Bangladesh - 1) Ganges- a snow-fed river regulated by upstream India 2) Brahmaputra - a snow-fed river that is also braided 3) Meghna - a rain-fed river. The quantitative assessment will show the effectiveness of the NASA Global Flood Detection System for a very humid and flood prone region like Bangladesh that is also faced with tremendous transboundary hurdles that can only be resolved from the vantage of space.

  18. Bias adjustment of satellite-based precipitation estimation using gauge observations: A case study in Chile

    Science.gov (United States)

    Yang, Zhongwen; Hsu, Kuolin; Sorooshian, Soroosh; Xu, Xinyi; Braithwaite, Dan; Verbist, Koen M. J.

    2016-04-01

    Satellite-based precipitation estimates (SPEs) are promising alternative precipitation data for climatic and hydrological applications, especially for regions where ground-based observations are limited. However, existing satellite-based rainfall estimations are subject to systematic biases. This study aims to adjust the biases in the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Cloud Classification System (PERSIANN-CCS) rainfall data over Chile, using gauge observations as reference. A novel bias adjustment framework, termed QM-GW, is proposed based on the nonparametric quantile mapping approach and a Gaussian weighting interpolation scheme. The PERSIANN-CCS precipitation estimates (daily, 0.04°×0.04°) over Chile are adjusted for the period of 2009-2014. The historical data (satellite and gauge) for 2009-2013 are used to calibrate the methodology; nonparametric cumulative distribution functions of satellite and gauge observations are estimated at every 1°×1° box region. One year (2014) of gauge data was used for validation. The results show that the biases of the PERSIANN-CCS precipitation data are effectively reduced. The spatial patterns of adjusted satellite rainfall show high consistency to the gauge observations, with reduced root-mean-square errors and mean biases. The systematic biases of the PERSIANN-CCS precipitation time series, at both monthly and daily scales, are removed. The extended validation also verifies that the proposed approach can be applied to adjust SPEs into the future, without further need for ground-based measurements. This study serves as a valuable reference for the bias adjustment of existing SPEs using gauge observations worldwide.

  19. Magnetic Launch Assist Experimental Track

    Science.gov (United States)

    1999-01-01

    In this photograph, a futuristic spacecraft model sits atop a carrier on the Magnetic Launch Assist System, formerly known as the Magnetic Levitation (MagLev) System, experimental track at the Marshall Space Flight Center (MSFC). Engineers at MSFC have developed and tested Magnetic Launch Assist technologies that would use magnetic fields to levitate and accelerate a vehicle along a track at very high speeds. Similar to high-speed trains and roller coasters that use high-strength magnets to lift and propel a vehicle a couple of inches above a guideway, a Magnetic Launch Assist system would electromagnetically drive a space vehicle along the track. A full-scale, operational track would be about 1.5-miles long and capable of accelerating a vehicle to 600 mph in 9.5 seconds. This track is an advanced linear induction motor. Induction motors are common in fans, power drills, and sewing machines. Instead of spinning in a circular motion to turn a shaft or gears, a linear induction motor produces thrust in a straight line. Mounted on concrete pedestals, the track is 100-feet long, about 2-feet wide, and about 1.5-feet high. The major advantages of launch assist for NASA launch vehicles is that it reduces the weight of the take-off, the landing gear, the wing size, and less propellant resulting in significant cost savings. The US Navy and the British MOD (Ministry of Defense) are planning to use magnetic launch assist for their next generation aircraft carriers as the aircraft launch system. The US Army is considering using this technology for launching target drones for anti-aircraft training.

  20. Infrared Measurements of Wheeled and Tracked Vehicles

    Science.gov (United States)

    2011-10-14

    International Range Instrumentation Group ( IRIG ) time, and run logging data). (3) Digital recording devices with IRIG time. (4) Global...spectrum) IRIG International Range Instrumentation Group K Kelvin km kilometer km/hr kilometer per hour LWIR Longwave-InfraRed (LWIR

  1. Tethered Vehicle Control and Tracking System

    Science.gov (United States)

    North, David D. (Inventor); Aull, Mark J. (Inventor)

    2017-01-01

    A kite system includes a kite and a ground station. The ground station includes a sensor that can be utilized to determine an angular position and velocity of the kite relative to the ground station. A controller utilizes a fuzzy logic control system to autonomously fly the kite. The system may include a ground station having powered winding units that generate power as the lines to the kite are unreeled. The control system may be configured to fly the kite in a crosswind trajectory to increase line tension for power generation. The sensors for determining the position of the kite are preferably ground-based.

  2. Dynamic model of vertical vehicle-subgrade coupled system under secondary suspension

    Institute of Scientific and Technical Information of China (English)

    LIANG Bo; LUO Hong; MA Xue-ning

    2007-01-01

    As it is known, track transportation can be divided into track system above and track system below. While the train is moving, the parts above and below are interacted and influenced. Therefore, in fact, the problem of track transportation is the match between the vehicle and the railway line system. In this paper, on a basis of dynamic analysis of the vehicle-subgrade model of vertical coupled system under primary suspension,utilizing track maintenance standard and simulating track irregularity excitation, the dynamic interaction of vehicle-track-subgrade system is researched in theory and dynamic model of the vertical vehicle-track-subgrade coupled system under secondary suspension is established by compatibility condition of deformation. Even this model considers the actual structure of a vehicle, also considers vibration characteristic of the substructure of track including subgrade and foundation. All these work want to be benefit for understanding and design about the dynamic characters of subgrade in high speed railway.

  3. Control design and implementation for a line tracker vehicle

    OpenAIRE

    Prats Martinho, Ivan Odair

    2016-01-01

    The aim of this project is to implement control algorithms in a line tracker vehicle. The vehicle should be built and controlled to track a path and the evaluation of the different control performances should be reported. The main goal of this work is to build a two-wheeled robot emulating a vehicle in a road. The aim of the overall project is to apply control techniques to different scenarios of communicated vehicles, such as: platooning, autonomous vehicles, overtaking maneuvers, automat...

  4. Electric vehicles

    Science.gov (United States)

    1990-03-01

    Quiet, clean, and efficient, electric vehicles (EVs) may someday become a practical mode of transportation for the general public. Electric vehicles can provide many advantages for the nation's environment and energy supply because they run on electricity, which can be produced from many sources of energy such as coal, natural gas, uranium, and hydropower. These vehicles offer fuel versatility to the transportation sector, which depends almost solely on oil for its energy needs. Electric vehicles are any mode of transportation operated by a motor that receives electricity from a battery or fuel cell. EVs come in all shapes and sizes and may be used for different tasks. Some EVs are small and simple, such as golf carts and electric wheel chairs. Others are larger and more complex, such as automobile and vans. Some EVs, such as fork lifts, are used in industries. In this fact sheet, we will discuss mostly automobiles and vans. There are also variations on electric vehicles, such as hybrid vehicles and solar-powered vehicles. Hybrid vehicles use electricity as their primary source of energy, however, they also use a backup source of energy, such as gasoline, methanol or ethanol. Solar-powered vehicles are electric vehicles that use photovoltaic cells (cells that convert solar energy to electricity) rather than utility-supplied electricity to recharge the batteries. These concepts are discussed.

  5. Demonstration of Heavy Hybrid Diesel Fleet Vehicles

    Science.gov (United States)

    2016-03-01

    losses due to uneven pavement , and representative of most installations. • Track Weather Station: ATC setup equipment to measure and record weather...the conventional utility truck provide a better, more rigid ride. Acceleration of the vehicle is very poor. The vehicles continuously fall behind

  6. GIO-EMS and International Collaboration in Satellite based Emergency Mapping

    Science.gov (United States)

    Kucera, Jan; Lemoine, Guido; Broglia, Marco

    2013-04-01

    During the last decade, satellite based emergency mapping has developed into a mature operational stage. The European Union's GMES Initial Operations - Emergency Management Service (GIO-EMS), is operational since April 2012. It's set up differs from other mechanisms (for example from the International Charter "Space and Major Disasters"), as it extends fast satellite tasking and delivery with the value adding map production as a single service, which is available, free of charge, to the authorized users of the service. Maps and vector datasets with standard characteristics and formats ranging from post-disaster damage assessment to recovery and disaster prevention are covered by this initiative. Main users of the service are European civil protection authorities and international organizations active in humanitarian aid. All non-sensitive outputs of the service are accessible to the public. The European Commission's in-house science service Joint Research Centre (JRC) is the technical and administrative supervisor of the GIO-EMS. The EC's DG ECHO Monitoring and Information Centre acts as the service's focal point and DG ENTR is responsible for overall service governance. GIO-EMS also aims to contribute to the synergy with similar existing mechanisms at national and international level. The usage of satellite data for emergency mapping has increased during the last years and this trend is expected to continue because of easier accessibility to suitable satellite and other relevant data in the near future. Furthermore, the data and analyses coming from volunteer emergency mapping communities are expected to further enrich the content of such cartographic products. In the case of major disasters the parallel activity of more providers is likely to generate non-optimal use of resources, e.g. unnecessary duplication; whereas coordination may lead to reduced time needed to cover the disaster area. Furthermore the abundant number of geospatial products of different

  7. Satellite based radar interferometry to estimate large-scale soil water depletion from clay shrinkage: possibilities and limitations

    NARCIS (Netherlands)

    Brake, te B.; Hanssen, R.F.; Ploeg, van der M.J.; Rooij, de G.H.

    2013-01-01

    Satellite-based radar interferometry is a technique capable of measuring small surface elevation changes at large scales and with a high resolution. In vadose zone hydrology, it has been recognized for a long time that surface elevation changes due to swell and shrinkage of clayey soils can serve as

  8. Providing satellite-based early warnings of fires to reduce fire flashovers on South Africa’s transmission lines

    CSIR Research Space (South Africa)

    Frost, PE

    2007-07-01

    Full Text Available The Advanced Fire Information System (AFIS) is the first near real time operational satellite-based fire monitoring system of its kind in Africa. The main aim of AFIS is to provide information regarding the prediction, detection and assessment...

  9. Multi-variable calibration of a semi-distributed hydrological model using streamflow data and satellite-based evapotranspiration

    NARCIS (Netherlands)

    Rientjes, T.H.M.; Muthuwatta, L.P.; Bos, M.G.; Booij, M.J.; Bhatti, H.A.

    2013-01-01

    In this study, streamflow (Qs) and satellite-based actual evapotranspiration (ETa) are used in a multi-variable calibration framework to reproduce the catchment water balance. The application is for the HBV rainfall–runoff model at daily time-step for the Karkheh River Basin (51,000 km2) in Iran. Mo

  10. Satellite based radar interferometry to estimate large-scale soil water depletion from clay shrinkage: possibilities and limitations

    NARCIS (Netherlands)

    Brake, te B.; Hanssen, R.F.; Ploeg, van der M.J.; Rooij, de G.H.

    2013-01-01

    Satellite-based radar interferometry is a technique capable of measuring small surface elevation changes at large scales and with a high resolution. In vadose zone hydrology, it has been recognized for a long time that surface elevation changes due to swell and shrinkage of clayey soils can serve as

  11. The Satellite based Monitoring Initiative for Regional Air quality (SAMIRA): Project summary and first results

    Science.gov (United States)

    Schneider, Philipp; Stebel, Kerstin; Ajtai, Nicolae; Diamandi, Andrei; Horalek, Jan; Nemuc, Anca; Stachlewska, Iwona; Zehner, Claus

    2017-04-01

    We present a summary and some first results of a new ESA-funded project entitled Satellite based Monitoring Initiative for Regional Air quality (SAMIRA), which aims at improving regional and local air quality monitoring through synergetic use of data from present and upcoming satellite instruments, traditionally used in situ air quality monitoring networks and output from chemical transport models. Through collaborative efforts in four countries, namely Romania, Poland, the Czech Republic and Norway, all with existing air quality problems, SAMIRA intends to support the involved institutions and associated users in their national monitoring and reporting mandates as well as to generate novel research in this area. The primary goal of SAMIRA is to demonstrate the usefulness of existing and future satellite products of air quality for improving monitoring and mapping of air pollution at the regional scale. A total of six core activities are being carried out in order to achieve this goal: Firstly, the project is developing and optimizing algorithms for the retrieval of hourly aerosol optical depth (AOD) maps from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) onboard of Meteosat Second Generation. As a second activity, SAMIRA aims to derive particulate matter (PM2.5) estimates from AOD data by developing robust algorithms for AOD-to-PM conversion with the support from model- and Lidar data. In a third activity, we evaluate the added value of satellite products of atmospheric composition for operational European-scale air quality mapping using geostatistics and auxiliary datasets. The additional benefit of satellite-based monitoring over existing monitoring techniques (in situ, models) is tested by combining these datasets using geostatistical methods and demonstrated for nitrogen dioxide (NO2), sulphur dioxide (SO2), and aerosol optical depth/particulate matter. As a fourth activity, the project is developing novel algorithms for downscaling coarse

  12. Impacts of Satellite-Based Snow Albedo Assimilation on Offline and Coupled Land Surface Model Simulations.

    Directory of Open Access Journals (Sweden)

    Tao Wang

    Full Text Available Seasonal snow cover in the Northern Hemisphere is the largest component of the terrestrial cryosphere and plays a major role in the climate system through strong positive feedbacks related to albedo. The snow-albedo feedback is invoked as an important cause for the polar amplification of ongoing and projected climate change, and its parameterization across models is an important source of uncertainty in climate simulations. Here, instead of developing a physical snow albedo scheme, we use a direct insertion approach to assimilate satellite-based surface albedo during the snow season (hereafter as snow albedo assimilation into the land surface model ORCHIDEE (ORganizing Carbon and Hydrology In Dynamic EcosystEms and assess the influences of such assimilation on offline and coupled simulations. Our results have shown that snow albedo assimilation in both ORCHIDEE and ORCHIDEE-LMDZ (a general circulation model of Laboratoire de Météorologie Dynamique improve the simulation accuracy of mean seasonal (October throughout May snow water equivalent over the region north of 40 degrees. The sensitivity of snow water equivalent to snow albedo assimilation is more pronounced in the coupled simulation than the offline simulation since the feedback of albedo on air temperature is allowed in ORCHIDEE-LMDZ. We have also shown that simulations of air temperature at 2 meters in ORCHIDEE-LMDZ due to snow albedo assimilation are significantly improved during the spring in particular over the eastern Siberia region. This is a result of the fact that high amounts of shortwave radiation during the spring can maximize its snow albedo feedback, which is also supported by the finding that the spatial sensitivity of temperature change to albedo change is much larger during the spring than during the autumn and winter. In addition, the radiative forcing at the top of the atmosphere induced by snow albedo assimilation during the spring is estimated to be -2.50 W m-2, the

  13. Impacts of Satellite-Based Snow Albedo Assimilation on Offline and Coupled Land Surface Model Simulations.

    Science.gov (United States)

    Wang, Tao; Peng, Shushi; Krinner, Gerhard; Ryder, James; Li, Yue; Dantec-Nédélec, Sarah; Ottlé, Catherine

    2015-01-01

    Seasonal snow cover in the Northern Hemisphere is the largest component of the terrestrial cryosphere and plays a major role in the climate system through strong positive feedbacks related to albedo. The snow-albedo feedback is invoked as an important cause for the polar amplification of ongoing and projected climate change, and its parameterization across models is an important source of uncertainty in climate simulations. Here, instead of developing a physical snow albedo scheme, we use a direct insertion approach to assimilate satellite-based surface albedo during the snow season (hereafter as snow albedo assimilation) into the land surface model ORCHIDEE (ORganizing Carbon and Hydrology In Dynamic EcosystEms) and assess the influences of such assimilation on offline and coupled simulations. Our results have shown that snow albedo assimilation in both ORCHIDEE and ORCHIDEE-LMDZ (a general circulation model of Laboratoire de Météorologie Dynamique) improve the simulation accuracy of mean seasonal (October throughout May) snow water equivalent over the region north of 40 degrees. The sensitivity of snow water equivalent to snow albedo assimilation is more pronounced in the coupled simulation than the offline simulation since the feedback of albedo on air temperature is allowed in ORCHIDEE-LMDZ. We have also shown that simulations of air temperature at 2 meters in ORCHIDEE-LMDZ due to snow albedo assimilation are significantly improved during the spring in particular over the eastern Siberia region. This is a result of the fact that high amounts of shortwave radiation during the spring can maximize its snow albedo feedback, which is also supported by the finding that the spatial sensitivity of temperature change to albedo change is much larger during the spring than during the autumn and winter. In addition, the radiative forcing at the top of the atmosphere induced by snow albedo assimilation during the spring is estimated to be -2.50 W m-2, the magnitude of

  14. Satellite-based RAR performance simulation for measuring directional ocean wave spectrum based on SAR inversion spectrum

    Institute of Scientific and Technical Information of China (English)

    REN Lin; MAO Zhihua; HUANG Haiqing; GONG Fang

    2010-01-01

    Some missions have been carried out to measure wave directional spectrum by synthetic aperture radar (SAR) and airborne real aperture radar (RAR) at a low incidence. Both them have their own advantages and limitations. Scientists hope that SAR and satellite-based RAR can complement each other for the research on wave properties in the future. For this study, the authors aim to simulate the satellite-based RAR system to validate performance for measuring the directional wave spectrum. The principal measurements are introduced and the simulation methods based on the one developed by Hauser are adopted and slightly modified. To enhance the authenticity of input spectrum and the wave spectrum measuring consistency for SAR and satellite-based RAR, the wave height spectrum inversed from Envisat ASAR data by cross spectrum technology is used as the input spectrum of the simulation system. In the process of simulation, the sea surface, backscattering signal, modulation spectrum and the estimated wave height spectrum are simulated in each look direction. Directional wave spectrum are measured based on the simulated observations from 0° to 360~. From the estimated wave spectrum, it has an 180° ambiguity like SAR, but it has no special high wave number cut off in all the direction. Finally, the estimated spectrum is compared with the input one in terms of the dominant wave wavelength, direction and SWH and the results are promising. The simulation shows that satellite-based RAR should be capable of measuring the directional wave properties. Moreover, it indicates satellite-based RAR basically can measure waves that SAR can measure.

  15. A new, long-term daily satellite-based rainfall dataset for operational monitoring in Africa

    Science.gov (United States)

    Maidment, Ross I.; Grimes, David; Black, Emily; Tarnavsky, Elena; Young, Matthew; Greatrex, Helen; Allan, Richard P.; Stein, Thorwald; Nkonde, Edson; Senkunda, Samuel; Alcántara, Edgar Misael Uribe

    2017-05-01

    Rainfall information is essential for many applications in developing countries, and yet, continually updated information at fine temporal and spatial scales is lacking. In Africa, rainfall monitoring is particularly important given the close relationship between climate and livelihoods. To address this information gap, this paper describes two versions (v2.0 and v3.0) of the TAMSAT daily rainfall dataset based on high-resolution thermal-infrared observations, available from 1983 to the present. The datasets are based on the disaggregation of 10-day (v2.0) and 5-day (v3.0) total TAMSAT rainfall estimates to a daily time-step using daily cold cloud duration. This approach provides temporally consistent historic and near-real time daily rainfall information for all of Africa. The estimates have been evaluated using ground-based observations from five countries with contrasting rainfall climates (Mozambique, Niger, Nigeria, Uganda, and Zambia) and compared to other satellite-based rainfall estimates. The results indicate that both versions of the TAMSAT daily estimates reliably detects rainy days, but have less skill in capturing rainfall amount—results that are comparable to the other datasets.

  16. Performance tests of a satellite-based asymmetric communication network for the 'hyper hospital'.

    Science.gov (United States)

    Yamaguchi, T

    1997-01-01

    The Hyper Hospital is a prototype networked telemedicine system which uses virtual reality. We measured the performance of a novel multimedia network based on satellite communications. The network was a hybrid system consisting of a satellite channel in one direction and a terrestrial channel in the other. Each user was equipped with a standard satellite communication receiver and a telephone connection. Requests from the users were sent by modern and telephone line and responses were received by satellite. The user requests were initiated by clicking buttons on a World Wide Web browser screen. The transmission rates of satellite and normal telephone-line communications were compared for standardized text data. Satellite communication was three to five times faster. The transmission rate was also measured for standardized graphical data (GIF format). With a file size of about 400 kByte, satellite-mediated communication was 10 times faster than telephone lines. The effect of simultaneous access on performance was also explored. For simultaneous access of nine users to a single graphics file, 78% of the transmission speed was obtained in comparison with that of a single user. The satellite-based system showed excellent high-speed communication performance, particularly for multimedia data.

  17. Characterization of absorbing aerosol types using ground and satellites based observations over an urban environment

    Science.gov (United States)

    Bibi, Samina; Alam, Khan; Chishtie, Farrukh; Bibi, Humera

    2017-02-01

    In this paper, for the first time, an effort has been made to seasonally characterize the absorbing aerosols into different types using ground and satellite based observations. For this purpose, optical properties of aerosol retrieved from AErosol RObotic NETwork (AERONET) and Ozone Monitoring Instrument (OMI) were utilized over Karachi for the period 2012 to 2014. Firstly, OMI AODabs was validated with AERONET AODabs and found to have a high degree of correlation. Then, based on this validation, characterization was conducted by analyzing aerosol Fine Mode Fraction (FMF), Angstrom Exponent (AE), Absorption Angstrom Exponent (AAE), Single Scattering Albedo (SSA) and Aerosol Index (AI) and their mutual correlation, to identify the absorbing aerosol types and also to examine the variability in seasonal distribution. The absorbing aerosols were characterized into Mostly Black Carbon (BC), Mostly Dust and Mixed BC & Dust. The results revealed that Mostly BC aerosols contributed dominantly during winter and postmonsoon whereas, Mostly Dust were dominant during summer and premonsoon. These types of absorbing aerosol were also confirmed with MODerate resolution Imaging Spectroradiometer (MODIS) and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) observations.

  18. Hydrological Modelling using Satellite-Based Crop Coefficients: A Comparison of Methods at the Basin Scale

    Directory of Open Access Journals (Sweden)

    Johannes E. Hunink

    2017-02-01

    Full Text Available The parameterization of crop coefficients (kc is critical for determining a water balance. We used satellite-based and literature-based methods to derive kc values for a distributed hydrologic model. We evaluated the impact of different kc parametrization methods on the water balance and simulated hydrologic response at the basin and sub-basin scale. The hydrological model SPHY was calibrated and validated for a period of 15 years for the upper Segura basin (~2500 km2 in Spain, which is characterized by a wide range of terrain, soil, and ecosystem conditions. The model was then applied, using six kc parameterization methods, to determine their spatial and temporal impacts on actual evapotranspiration, streamflow, and soil moisture. The parameterization methods used include: (i Normalized Difference Vegetation Index (NDVI observations from MODIS; (ii seasonally-averaged NDVI patterns, cell-based and landuse-based; and (iii literature-based tabular values per land use type. The analysis shows that the influence of different kc parametrization methods on basin-level streamflow is relatively small and constant throughout the year, but it has a bigger effect on seasonal evapotranspiration and soil moisture. In the autumn especially, deviations can go up to about 15% of monthly streamflow. At smaller, sub-basin scale, deviations from the NDVI-based reference run can be more than 30%. Overall, the study shows that modeling of future hydrological changes can be improved by using remote sensing information for the parameterization of crop coefficients.

  19. Development and validation of satellite-based estimates of surface visibility

    Science.gov (United States)

    Brunner, J.; Pierce, R. B.; Lenzen, A.

    2016-02-01

    A satellite-based surface visibility retrieval has been developed using Moderate Resolution Imaging Spectroradiometer (MODIS) measurements as a proxy for Advanced Baseline Imager (ABI) data from the next generation of Geostationary Operational Environmental Satellites (GOES-R). The retrieval uses a multiple linear regression approach to relate satellite aerosol optical depth, fog/low cloud probability and thickness retrievals, and meteorological variables from numerical weather prediction forecasts to National Weather Service Automated Surface Observing System (ASOS) surface visibility measurements. Validation using independent ASOS measurements shows that the GOES-R ABI surface visibility retrieval (V) has an overall success rate of 64.5 % for classifying clear (V ≥ 30 km), moderate (10 km ≤ V skill during June through September, when Heidke skill scores are between 0.2 and 0.4. We demonstrate that the aerosol (clear-sky) component of the GOES-R ABI visibility retrieval can be used to augment measurements from the United States Environmental Protection Agency (EPA) and National Park Service (NPS) Interagency Monitoring of Protected Visual Environments (IMPROVE) network and provide useful information to the regional planning offices responsible for developing mitigation strategies required under the EPA's Regional Haze Rule, particularly during regional haze events associated with smoke from wildfires.

  20. Satellite-based detection of global urban heat-island temperature influence

    Science.gov (United States)

    Gallo, K.P.; Adegoke, Jimmy O.; Owen, T.W.; Elvidge, C.D.

    2002-01-01

    This study utilizes a satellite-based methodology to assess the urban heat-island influence during warm season months for over 4400 stations included in the Global Historical Climatology Network of climate stations. The methodology includes local and regional satellite retrievals of an indicator of the presence green photosynthetically active vegetation at and around the stations. The difference in local and regional samples of the normalized difference vegetation index (NDVI) is used to estimate differences in mean air temperature. Stations classified as urban averaged 0.90??C (N. Hemisphere) and 0.92??C (S. Hemisphere) warmer than the surrounding environment on the basis of the NDVI-derived temperature estimates. Additionally, stations classified as rural averaged 0.19??C (N. Hemisphere) and 0.16??C (S. Hemisphere) warmer than the surrounding environment. The NDVI-derived temperature estimates were found to be in reasonable agreement with temperature differences observed between climate stations. The results suggest that satellite-derived data sets can be used to estimate the urban heat-island temperature influence on a global basis and that a more detailed analysis of rural stations and their surrounding environment may be necessary to assure that temperature trends derived from assumed rural environments are not influenced by changes in land use/land cover. Copyright 2002 by the American Geophysical Union.

  1. An Exploitation of Satellite-based Observation for Health Information: The UFOS Project

    Energy Technology Data Exchange (ETDEWEB)

    Mangin, A.; Morel, M.; Fanton d' Andon, O

    2000-07-01

    Short, medium and long-term trends of UV intensity levels are of crucial importance for either assessing effective biological impacts on human population, or implementing adequate preventive behaviours. Better information on a large spatial scale and increased public awareness of the short-term variations in UV values will help to support health agencies' goals of educating the public on UV risks. The Ultraviolet Forecast Operational Service Project (UFAS), financed in part by the European Commission/DG Information Society (TEN-TELECOM programme), aims to exploit satellite-based observations and to supply a set of UV products directly useful to health care. The short-term objective is to demonstrate the technical and economical feasibility and benefits that could be brought by such a system. UFOS is carried out by ACRI, with the support of an Advisory Group chaired by WHO and involving representation from the sectors of Health (WHO, INTERSUN collaborating centres, ZAMBON), Environment (WMO, IASB), and Telecommunications (EURECOM, IMET). (author)

  2. Satellite-based Studies on Large-Scale Vegetation Changes in China

    Institute of Scientific and Technical Information of China (English)

    Xia Zhao; Daojing Zhou; Jingyun Fang

    2012-01-01

    Remotely-sensed vegetation indices,which indicate the density and photosynthetic capacity of vegetation,have been widely used to monitor vegetation dynamics over broad areas.In this paper,we reviewed satellite-based studies on vegetation cover changes,biomass and productivity variations,phenological dynamics,desertification,and grassland degradation in China that occurred over the past 2-3 decades.Our review shows that the satellite-derived index (Normalized Difference Vegetation Index,NDVI) during growing season and the vegetation net primary productivity in major terrestrial ecosystems (for example forests,grasslands,shrubs,and croplands) have significantly increased,while the number of fresh lakes and vegetation coverage in urban regions have experienced a substantial decline.The start of the growing season continually advanced in China's temperate regions until the 1990s,with a large spatial heterogeneity.We also found that the coverage of sparsely-vegetated areas declined,and the NDVI per unit in vegetated areas increased in arid and semi-arid regions because of increased vegetation activity in grassland and oasis areas.However,these results depend strongly not only on the periods chosen for investigation,but also on factors such as data sources,changes in detection methods,and geospatial heterogeneity.Therefore,we should be cautious when applying remote sensing techniques to monitor vegetation structures,functions,and changes.

  3. Heavy rainfall prediction applying satellite-based cloud data assimilation over land

    Science.gov (United States)

    Seto, Rie; Koike, Toshio; Rasmy, Mohamed

    2016-08-01

    To optimize flood management, it is crucial to determine whether rain will fall within a river basin. This requires very fine precision in prediction of rainfall areas. Cloud data assimilation has great potential to improve the prediction of precipitation area because it can directly obtain information on locations of rain systems. Clouds can be observed globally by satellite-based microwave remote sensing. Microwave observation also includes information of latent heat and water vapor associated with cloud amount, which enables the assimilation of not only cloud itself but also the cloud-affected atmosphere. However, it is difficult to observe clouds over land using satellite microwave remote sensing, because their emissivity is much lower than that of the land surface. To overcome this challenge, we need appropriate representation of heterogeneous land emissivity. We developed a coupled atmosphere and land data assimilation system with the Weather Research and Forecasting Model (CALDAS-WRF), which can assimilate soil moisture, vertically integrated cloud water content over land, and heat and moisture within clouds simultaneously. We applied this system to heavy rain events in Japan. Results show that the system effectively assimilated cloud signals and produced very accurate cloud and precipitation distributions. The system also accurately formed a consistent atmospheric field around the cloud. Precipitation intensity was also substantially improved by appropriately representing the local atmospheric field. Furthermore, combination of the method and operationally analyzed dynamical and moisture fields improved prediction of precipitation duration. The results demonstrate the method's promise in dramatically improving predictions of heavy rain and consequent flooding.

  4. Towards the Development of a Global, Satellite-based, Terrestrial Snow Mission Planning Tool

    Science.gov (United States)

    Forman, Bart; Kumar, Sujay; Le Moigne, Jacqueline; Nag, Sreeja

    2017-01-01

    A global, satellite-based, terrestrial snow mission planning tool is proposed to help inform experimental mission design with relevance to snow depth and snow water equivalent (SWE). The idea leverages the capabilities of NASAs Land Information System (LIS) and the Tradespace Analysis Tool for Constellations (TAT C) to harness the information content of Earth science mission data across a suite of hypothetical sensor designs, orbital configurations, data assimilation algorithms, and optimization and uncertainty techniques, including cost estimates and risk assessments of each hypothetical orbital configuration.One objective the proposed observing system simulation experiment (OSSE) is to assess the complementary or perhaps contradictory information content derived from the simultaneous collection of passive microwave (radiometer), active microwave (radar), and LIDAR observations from space-based platforms. The integrated system will enable a true end-to-end OSSE that can help quantify the value of observations based on their utility towards both scientific research and applications as well as to better guide future mission design. Science and mission planning questions addressed as part of this concept include:1. What observational records are needed (in space and time) to maximize terrestrial snow experimental utility?2. How might observations be coordinated (in space and time) to maximize utility? 3. What is the additional utility associated with an additional observation?4. How can future mission costs being minimized while ensuring Science requirements are fulfilled?

  5. The satellite based augmentation system – EGNOS for non-precision approach global navigation satellite system

    Directory of Open Access Journals (Sweden)

    Andrzej FELLNER

    2012-01-01

    Full Text Available First in the Poland tests of the EGNOS SIS (Signal in Space were conducted on 5th October 2007 on the flight inspection with SPAN (The Synchronized Position Attitude Navigation technology at the Mielec airfield. This was an introduction to a test campaign of the EGNOS-based satellite navigation system for air traffic. The advanced studies will be performed within the framework of the EGNOS-APV project in 2011. The implementation of the EGNOS system to APV-I precision approach operations, is conducted according to ICAO requirements in Annex 10. Definition of usefulness and certification of EGNOS as SBAS (Satellite Based Augmentation System in aviation requires thorough analyses of accuracy, integrity, continuity and availability of SIS. Also, the project will try to exploit the excellent accuracy performance of EGNOS to analyze the implementation of GLS (GNSS Landing System approaches (Cat I-like approached using SBAS, with a decision height of 200 ft. Location of the EGNOS monitoring station Rzeszów, located near Polish-Ukrainian border, being also at the east border of planned EGNOS coverage for ECAC states is very useful for SIS tests in this area. According to current EGNOS programmed schedule, the project activities will be carried out with EGNOS system v2.2, which is the version released for civil aviation certification. Therefore, the project will allow demonstrating the feasibility of the EGNOS certifiable version for civil applications.

  6. Application of Satellite-Based Spectrally-Resolved Solar Radiation Data to PV Performance Studies

    Directory of Open Access Journals (Sweden)

    Ana Maria Gracia Amillo

    2015-04-01

    Full Text Available In recent years, satellite-based solar radiation data resolved in spectral bands have become available. This has for the first time made it possible to produce maps of the geographical variation in the solar spectrum. It also makes it possible to estimate the influence of these variations on the performance of photovoltaic (PV modules. Here, we present a study showing the magnitude of the spectral influence on PV performance over Europe and Africa. The method has been validated using measurements of a CdTe module in Ispra, Italy, showing that the method predicts the spectral influence to within ±2% on a monthly basis and 0.1% over a 19-month period. Application of the method to measured spectral responses of crystalline silicon, CdTe and single-junction amorphous silicon (a-Si modules shows that the spectral effect is smallest over desert areas for all module types, higher in temperate Europe and highest in tropical Africa, where CdTe modules would be expected to yield +6% and single- junction a-Si modules up to +10% more energy due to spectral effects. In contrast, the effect for crystalline silicon modules is less than ±1% in nearly all of Africa and Southern Europe, rising to +1% or +2% in Northern Europe.

  7. ROLLING NOISE SIMULATION OF A RAILWAY VEHICLE

    Directory of Open Access Journals (Sweden)

    Traian MAZILU

    2013-05-01

    Full Text Available Rolling noise of the railway vehicles is occurred by the wheel/rail vibration excited bythe rolling surfaces roughness. This paper presents an acoustic model able to predict the rollingnoise level of a railway vehicle. The acoustic model is based on a wheel/rail vibration modelwhich takes into account the structural wheel vibration (Remington model and the bendingvertical waves of the rail. To this, the track model with an infinite Euler Bernoulli beam elasticallysupported on two layers is applied to simulate the effect of the ballasted track. The influence of therolling surfaces roughness and vehicle velocity on the rolling noise is investigated.

  8. Ground moving target processing for tracking selected targets

    Science.gov (United States)

    Nichols, Howard; Majumder, Uttam; Owirka, Gregory; Finn, Lucas

    2016-05-01

    BAE Systems has developed a baseline real-time selected vehicle (SV) radar tracking capability that successfully tracked multiple civilian vehicles in real-world traffic conditions within challenging semi-urban clutter. This real-time tracking capability was demonstrated in laboratory setting. Recent enhancements to the baseline capability include multiple detection modes, improvements to the system-level design, and a wide-area tracking mode. The multiple detection modes support two tracking regimes; wide-area and localized selected vehicle tracking. These two tracking regimes have distinct challenges that may be suited to different trackers. Incorporation of a wide-area tracking mode provides both situational awareness and the potential for enhancing SV track initiation. Improvements to the system-level design simplify the integration of multiple detection modes and more realistic SV track initiation capabilities. Improvements are designed to contribute to a comprehensive tracking capability that exploits a continuous stare paradigm. In this paper, focus will be on the challenges, design considerations, and integration of selected vehicle tracking.

  9. Tabletop Experimental Track for Magnetic Launch Assist

    Science.gov (United States)

    2000-01-01

    Marshall Space Flight Center's (MSFC's) Advanced Space Transportation Program has developed the Magnetic Launch Assist System, formerly known as the Magnetic Levitation (MagLev) technology that could give a space vehicle a running start to break free from Earth's gravity. A Magnetic Launch Assist system would use magnetic fields to levitate and accelerate a vehicle along a track at speeds up to 600 mph. The vehicle would shift to rocket engines for launch into orbit. Similar to high-speed trains and roller coasters that use high-strength magnets to lift and propel a vehicle a couple of inches above a guideway, a Magnetic Launch Assist system would electromagnetically propel a space vehicle along the track. The tabletop experimental track for the system shown in this photograph is 44-feet long, with 22-feet of powered acceleration and 22-feet of passive braking. A 10-pound carrier with permanent magnets on its sides swiftly glides by copper coils, producing a levitation force. The track uses a linear synchronous motor, which means the track is synchronized to turn the coils on just before the carrier comes in contact with them, and off once the carrier passes. Sensors are positioned on the side of the track to determine the carrier's position so the appropriate drive coils can be energized. MSFC engineers have conducted tests on the indoor track and a 50-foot outdoor track. The major advantages of launch assist for NASA launch vehicles is that it reduces the weight of the take-off, the landing gear, the wing size, and less propellant resulting in significant cost savings. The US Navy and the British MOD (Ministry of Defense) are planning to use magnetic launch assist for their next generation aircraft carriers as the aircraft launch system. The US Army is considering using this technology for launching target drones for anti-aircraft training.

  10. Torque vectoring for improving stability of small electric vehicles

    Science.gov (United States)

    Grzegożek, W.; Weigel-Milleret, K.

    2016-09-01

    The electric vehicles solutions based on the individually controlled electric motors propel a single wheel allow to improve the dynamic properties of the vehicle by varying the distribution of the driving torque. Most of the literature refer to the vehicles with a track typical for passenger cars. This paper examines whether the narrow vehicle (with a very small track) torque vectoring bring a noticeable change of the understeer characteristics and whether torque vectoring is possible to use in securing a narrow vehicle from roll over (roll mitigation). The paper contains road tests of the steering characteristics (steady state understeer characteristic quasi-static acceleration with a fixed steering wheel (SH = const) and on the constant radius track (R = const)) of the narrow vehicle. The vehicle understeer characteristic as a function of a power distribution is presented.

  11. Vehicle management system-system analysis and design

    Institute of Scientific and Technical Information of China (English)

    CHENG Ke-fei; LONG Hua; ZHANG Cong

    2004-01-01

    This paper presents one of GPS Vehicle Monitor System on base of Web-GIS technology, which is very important in vehicle tracking, scheduling and management. In the paper, a real GPS vehicle monitor system which using Internet technology is introduced. This system have been putted into practice successfully.

  12. Categorizing natural disaster damage assessment using satellite-based geospatial techniques

    Directory of Open Access Journals (Sweden)

    S. W. Myint

    2008-07-01

    Full Text Available Remote sensing of a natural disaster's damage offers an exciting backup and/or alternative to traditional means of on-site damage assessment. Although necessary for complete assessment of damage areas, ground-based damage surveys conducted in the aftermath of natural hazard passage can sometimes be potentially complicated due to on-site difficulties (e.g., interaction with various authorities and emergency services and hazards (e.g., downed power lines, gas lines, etc., the need for rapid mobilization (particularly for remote locations, and the increasing cost of rapid physical transportation of manpower and equipment. Satellite image analysis, because of its global ubiquity, its ability for repeated independent analysis, and, as we demonstrate here, its ability to verify on-site damage assessment provides an interesting new perspective and investigative aide to researchers. Using one of the strongest tornado events in US history, the 3 May 1999 Oklahoma City Tornado, as a case example, we digitized the tornado damage path and co-registered the damage path using pre- and post-Landsat Thematic Mapper image data to perform a damage assessment. We employed several geospatial approaches, specifically the Getis index, Geary's C, and two lacunarity approaches to categorize damage characteristics according to the original Fujita tornado damage scale (F-scale. Our results indicate strong relationships between spatial indices computed within a local window and tornado F-scale damage categories identified through the ground survey. Consequently, linear regression models, even incorporating just a single band, appear effective in identifying F-scale damage categories using satellite imagery. This study demonstrates that satellite-based geospatial techniques can effectively add spatial perspectives to natural disaster damages, and in particular for this case study, tornado damages.

  13. Categorizing natural disaster damage assessment using satellite-based geospatial techniques

    Science.gov (United States)

    Myint, S. W.; Yuan, M.; Cerveny, R. S.; Giri, C.

    2008-07-01

    Remote sensing of a natural disaster's damage offers an exciting backup and/or alternative to traditional means of on-site damage assessment. Although necessary for complete assessment of damage areas, ground-based damage surveys conducted in the aftermath of natural hazard passage can sometimes be potentially complicated due to on-site difficulties (e.g., interaction with various authorities and emergency services) and hazards (e.g., downed power lines, gas lines, etc.), the need for rapid mobilization (particularly for remote locations), and the increasing cost of rapid physical transportation of manpower and equipment. Satellite image analysis, because of its global ubiquity, its ability for repeated independent analysis, and, as we demonstrate here, its ability to verify on-site damage assessment provides an interesting new perspective and investigative aide to researchers. Using one of the strongest tornado events in US history, the 3 May 1999 Oklahoma City Tornado, as a case example, we digitized the tornado damage path and co-registered the damage path using pre- and post-Landsat Thematic Mapper image data to perform a damage assessment. We employed several geospatial approaches, specifically the Getis index, Geary's C, and two lacunarity approaches to categorize damage characteristics according to the original Fujita tornado damage scale (F-scale). Our results indicate strong relationships between spatial indices computed within a local window and tornado F-scale damage categories identified through the ground survey. Consequently, linear regression models, even incorporating just a single band, appear effective in identifying F-scale damage categories using satellite imagery. This study demonstrates that satellite-based geospatial techniques can effectively add spatial perspectives to natural disaster damages, and in particular for this case study, tornado damages.

  14. Magnetic resonance imaging research in sub-Saharan Africa: challenges and satellite-based networking implementation.

    Science.gov (United States)

    Latourette, Matthew T; Siebert, James E; Barto, Robert J; Marable, Kenneth L; Muyepa, Anthony; Hammond, Colleen A; Potchen, Michael J; Kampondeni, Samuel D; Taylor, Terrie E

    2011-08-01

    As part of an NIH-funded study of malaria pathogenesis, a magnetic resonance (MR) imaging research facility was established in Blantyre, Malaŵi to enhance the clinical characterization of pediatric patients with cerebral malaria through application of neurological MR methods. The research program requires daily transmission of MR studies to Michigan State University (MSU) for clinical research interpretation and quantitative post-processing. An intercontinental satellite-based network was implemented for transmission of MR image data in Digital Imaging and Communications in Medicine (DICOM) format, research data collection, project communications, and remote systems administration. Satellite Internet service costs limited the bandwidth to symmetrical 384 kbit/s. DICOM routers deployed at both the Malaŵi MRI facility and MSU manage the end-to-end encrypted compressed data transmission. Network performance between DICOM routers was measured while transmitting both mixed clinical MR studies and synthetic studies. Effective network latency averaged 715 ms. Within a mix of clinical MR studies, the average transmission time for a 256 × 256 image was ~2.25 and ~6.25 s for a 512 × 512 image. Using synthetic studies of 1,000 duplicate images, the interquartile range for 256 × 256 images was [2.30, 2.36] s and [5.94, 6.05] s for 512 × 512 images. Transmission of clinical MRI studies between the DICOM routers averaged 9.35 images per minute, representing an effective channel utilization of ~137% of the 384-kbit/s satellite service as computed using uncompressed image file sizes (including the effects of image compression, protocol overhead, channel latency, etc.). Power unreliability was the primary cause of interrupted operations in the first year, including an outage exceeding 10 days.

  15. On the value of satellite-based river discharge and river flood data

    Science.gov (United States)

    Kettner, A. J.; Brakenridge, R.; van Praag, E.; Borrero, S.; Slayback, D. A.; Young, C.; Cohen, S.; Prades, L.; de Groeve, T.

    2015-12-01

    Flooding is the most common natural hazard worldwide. According to the World Resources Institute, floods impact 21 million people every year and affect the global GDP by $96 billion. Providing accurate flood maps in near-real time (NRT) is critical to their utility to first responders. Also, in times of flooding, river gauging stations on location, if any, are of less use to monitor stage height as an approximation for water surface area, as often the stations themselves get washed out or peak water levels reach much beyond their design measuring capacity. In a joint effort with NASA Goddard Space Flight Center, the European Commission Joint Research Centre and the University of Alabama, the Dartmouth Flood Observatory (DFO) measures NRT: 1) river discharges, and 2) water inundation extents, both with a global coverage on a daily basis. Satellite-based passive microwave sensors and hydrological modeling are utilized to establish 'remote-sensing based discharge stations'. Once calibrated, daily discharge time series span from 1998 to the present. Also, the two MODIS instruments aboard the NASA Terra and Aqua satellites provide daily floodplain inundation extent with global coverage at a spatial resolution of 250m. DFO's mission is to provide easy access to NRT river and flood data products. Apart from the DFO web portal, several water extent products can be ingested by utilizing a Web Map Service (WMS), such as is established with for Latin America and the Caribbean (LAC) region through the GeoSUR program portal. This effort includes implementing over 100 satellite discharge stations showing in NRT if a river is flooding, normal, or in low flow. New collaborative efforts have resulted in flood hazard maps which display flood extent as well as exceedance probabilities. The record length of our sensors allows mapping the 1.5 year, 5 year and 25 year flood extent. These can provide key information to water management and disaster response entities.

  16. Satellite-based technique for nowcasting of thunderstorms over Indian region

    Indian Academy of Sciences (India)

    Suman Goyal; Ashish Kumar; M Mohapatra; L S Rathore; S K Dube; Rahul Saxena; R K Giri

    2017-08-01

    India experiences severe thunderstorms during the months, March–June. But these systems are not predicted well, mainly due to the absence of mesoscale observational network over Indian region and the expert system. As these are short lived systems, the nowcast is attempted worldwide based on satellite and radar observations. Due to inadequate radar network, satellite plays the dominant role for nowcast of these thunderstorms. In this study, a nowcast based algorithm ForTracc developed by Vila et al. (Weather Forecast 23:233–245, 2008) has been examined over the Indian region using Infrared Channel (10.8 μm) of INSAT-3D for prediction of Mesoscale Convective Systems (MCS). In this technique, the current location and intensity in terms of Cloud Top Brightness Temperature (CTBT) of the MCS are extrapolated. The purpose of this study is to validate this satellite-based nowcasting technique for Convective Cloud Clusters that helps in optimum utilization of satellite data and improve the nowcasting. The model could predict reasonably the minimum CTBT of the convective cell with average absolute error (AAE) of <7 K for different lead periods (30–180 min). However, it was underestimated for all the lead periods of forecasts. The AAE in the forecasts of size of the cluster varies from about 3×104 km2 for 30-min forecast to 7×104 km2 for 120-min forecast. The mean absolute error in prediction of size is above 31–38% of actual size for different lead periods of forecasts from 30 to 180 min. There is over estimation in prediction of size for 30 and 60 min forecasts (17% and 2.6% of actual size of the cluster, respectively) and underestimation in 90 to 180-min forecasts (–2.4% to –28%). The direct position error (DPE) based on the location of minimum CTBT ranges from 70 to 144 km for 30–180-min forecast respectively.

  17. Adjusting thresholds of satellite-based convective initiation interest fields based on the cloud environment

    Science.gov (United States)

    Jewett, Christopher P.; Mecikalski, John R.

    2013-11-01

    The Time-Space Exchangeability (TSE) concept states that similar characteristics of a given property are closely related statistically for objects or features within close proximity. In this exercise, the objects considered are growing cumulus clouds, and the data sets to be considered in a statistical sense are geostationary satellite infrared (IR) fields that help describe cloud growth rates, cloud top heights, and whether cloud tops contain significant amounts of frozen hydrometeors. In this exercise, the TSE concept is applied to alter otherwise static thresholds of IR fields of interest used within a satellite-based convective initiation (CI) nowcasting algorithm. The convective environment in which the clouds develop dictate growth rate and precipitation processes, and cumuli growing within similar mesoscale environments should have similar growth characteristics. Using environmental information provided by regional statistics of the interest fields, the thresholds are examined for adjustment toward improving the accuracy of 0-1 h CI nowcasts. Growing cumulus clouds are observed within a CI algorithm through IR fields for many 1000 s of cumulus cloud objects, from which statistics are generated on mesoscales. Initial results show a reduction in the number of false alarms of ~50%, yet at the cost of eliminating approximately ~20% of the correct CI forecasts. For comparison, static thresholds (i.e., with the same threshold values applied across the entire satellite domain) within the CI algorithm often produce a relatively high probability of detection, with false alarms being a significant problem. In addition to increased algorithm performance, a benefit of using a method like TSE is that a variety of unknown variables that influence cumulus cloud growth can be accounted for without need for explicit near-cloud observations that can be difficult to obtain.

  18. A Comparison of Different Regression Algorithms for Downscaling Monthly Satellite-Based Precipitation over North China

    Directory of Open Access Journals (Sweden)

    Wenlong Jing

    2016-10-01

    Full Text Available Environmental monitoring of Earth from space has provided invaluable information for understanding land–atmosphere water and energy exchanges. However, the use of satellite-based precipitation observations in hydrologic and environmental applications is often limited by their coarse spatial resolutions. In this study, we propose a downscaling approach based on precipitation–land surface characteristics. Daytime land surface temperature, nighttime land surface temperature, and day–night land surface temperature differences were introduced as variables in addition to the Normalized Difference Vegetation Index (NDVI, the Digital Elevation Model (DEM, and geolocation (longitude, latitude. Four machine learning regression algorithms, the classification and regression tree (CART, the k-nearest neighbors (k-NN, the support vector machine (SVM, and random forests (RF, were implemented to downscale monthly TRMM 3B43 V7 precipitation data from 25 km to 1 km over North China for the purpose of comparison of algorithm performance. The downscaled results were validated based on observations from meteorological stations and were also compared to a previous downscaling algorithm. According to the validation results, the RF-based model produced the results with the highest accuracy. It was followed by SVM, CART, and k-NN, but the accuracy of the downscaled results using SVM relied greatly on residual correction. The downscaled results were well correlated with the observations during the year, but the accuracies were relatively lower in July to September. Downscaling errors increase as monthly total precipitation increases, but the RF model was less affected by this proportional effect between errors and observation compared with the other algorithms. The variable importances of the land surface temperature (LST feature variables were higher than those of NDVI, which indicates the significance of considering the precipitation–land surface temperature

  19. Long-term change analysis of satellite-based evapotranspiration over Indian vegetated surface

    Science.gov (United States)

    Gupta, Shweta; Bhattacharya, Bimal K.; Krishna, Akhouri P.

    2016-05-01

    In the present study, trend of satellite based annual evapotranspiration (ET) and natural forcing factors responsible for this were analyzed. Thirty years (1981-2010) of ET data at 0.08° grid resolution, generated over Indian region from opticalthermal observations from NOAA PAL and MODIS AQUA satellites, were used. Long-term data on gridded (0.5° x 0.5°) annual rainfall (RF), annual mean surface soil moisture (SSM) ERS scatterometer at 25 km resolution and annual mean incoming shortwave radiation from MERRA-2D reanalysis were also analyzed. Mann-Kendall tests were performed with time series data for trend analysis. Mean annual ET loss from Indian ago-ecosystem was found to be almost double (1100 Cubic Km) than Indian forest ecosystem (550 Cubic Km). Rainfed vegetation systems such as forest, rainfed cropland, grassland showed declining ET trend @ - 4.8, -0.6 &-0.4 Cubic Kmyr-1, respectively during 30 years. Irrigated cropland initially showed ET decline upto 1995 @ -0.8 cubic Kmyr-1 which could possibly be due to solar dimming followed by increasing ET @ 0.9 cubic Kmyr-1 after 1995. A cross-over point was detected between forest ET decline and ET increase in irrigated cropland during 2008. During 2001-2010, the four agriculturally important Indian states eastern, central, western and southern showed significantly increasing ET trend with S-score of 15-25 and Z-score of 1.09-2.9. Increasing ET in western and southern states was found to be coupled with increase in annual rainfall and SSM. But in eastern and central states no significant trend in rainfall was observed though significant increase in ET was noticed. The study recommended to investigate the influence of anthropogenic factors such as increase in area under irrigation, increased use of water for irrigation through ground water pumping, change in cropping pattern and cultivars on increasing ET.

  20. Satellite Based Analysis of Carbon Monoxide Levels Over Alberta Oil Sand

    Science.gov (United States)

    Marey, H. S.; Hashisho, Z.; Fu, L.; Gille, J. C.

    2014-12-01

    The rapid expansion of oil sands activities and massive energy requirements to extract and upgrade the bitumen require a comprehensive understanding of their potential environmental impacts, particularly on air quality. In this study, satellite-based analysis of carbon monoxide (CO) levels was used to assess the magnitude and distribution of this pollutant throughout Alberta oil sands region. Measurements of Pollution in the Troposphere (MOPITT) V5 multispectral product that uses both near-infrared and the thermal-infrared radiances for CO retrieval were used. MOPITT-based climatology and inter-annual variations were examined for 12 years (2002-2013) on spatial and temporal scales. Seasonal climatological maps for CO total columns indicated conspicuous spatial variations in all seasons except in winter where the CO spatial variations are less prominent. High CO loadings are observed to extend from the North East to North West regions of Alberta, with highest values in spring. The CO mixing ratios at the surface level in winter and spring seasons exhibited dissimilar spatial distribution pattern where the enhancements are detected in south eastern rather than northern Alberta. Analyzing spatial distributions of Omega at 850 mb pressure level for four seasons implied that, conditions in northeastern Alberta are more favorable for up lofting while in southern Alberta, subsidence of CO emissions are more likely. Time altitude CO profile climatology as well as the inter-annual variability were investigated for the oil sands and main urban regions in Alberta to assess the impact of various sources on CO loading. Monthly variations over urban regions are consistent with the general seasonal cycle of CO in Northern Hemisphere which exhibits significant enhancement in winter and spring, and minimum mixing ratios in summer. The typical seasonal CO variations over the oil sands region are less prominent. This study has demonstrated the potential use of multispectral CO

  1. South African Weather Service operational satellite based precipitation estimation technique: applications and improvements

    Directory of Open Access Journals (Sweden)

    E. de Coning

    2010-11-01

    Full Text Available Extreme weather related to heavy or more frequent precipitation events seem to be a likely possibility for the future of our planet. While precipitation measurements can be done by means of rain gauges, the obvious disadvantages of point measurements are driving meteorologists towards remotely sensed precipitation methods. In South Africa more sophisticated and expensive nowcasting technology such as radar and lightning networks are available, supported by a fairly dense rain gauge network of about 1500 gauges. In the rest of southern Africa rainfall measurements are more difficult to obtain. The availability of the local version of the Unified Model and the Meteosat Second Generation satellite data make these products ideal components of precipitation measurement in data sparse regions such as Africa. In this article the local version of the Hydroestimator (originally from NOAA/NESDIS is discussed as well as its applications for precipitation measurement in this region. Hourly accumulations of the Hydroestimator are currently used as a satellite based precipitation estimator for the South African Flash Flood Guidance system. However, the Hydroestimator is by no means a perfect representation of the real rainfall. In this study the Hydroestimator and the stratiform rainfall field from the Unified Model are both bias corrected and then combined into a new precipitation field which can feed into the South African Flash Flood Guidance system. This new product should provide a more accurate and comprehensive input to the Flash Flood Guidance systems in South Africa as well as southern Africa. In this way the southern African region where data is sparse and very few radars are available can have access to more accurate flash flood guidance.

  2. Developing an improved soil moisture dataset by blending passive and active microwave satellite-based retrievals

    Directory of Open Access Journals (Sweden)

    Y. Y. Liu

    2010-09-01

    Full Text Available Combining information derived from satellite-based passive and active microwave sensors has the potential to offer improved retrievals of surface soil moisture variations at global scales. Here we propose a technique to take advantage of retrieval characteristics of passive (AMSR-E and active (ASCAT microwave satellite estimates over sparse-to-moderately vegetated areas to obtain an improved soil moisture product. To do this, absolute soil moisture values from AMSR-E and relative soil moisture derived from ASCAT are rescaled against a reference land surface model date set using a cumulative distribution function (CDF matching approach. While this technique imposes the bias of the reference to the rescaled satellite products, it adjusts both satellite products to the same range and almost preserves the correlation between satellite products and in situ measurements. Comparisons with in situ data demonstrated that over the regions where the correlation coefficient between rescaled AMSR-E and ASCAT is above 0.65 (hereafter referred to as transitional regions, merging the different satellite products together increases the number of observations while minimally changing the accuracy of soil moisture retrievals. These transitional regions also delineate the boundary between sparsely and moderately vegetated regions where rescaled AMSR-E and ASCAT are respectively used in the merged product. Thus the merged product carries the advantages of better spatial coverage overall and increased number of observations particularly for the transitional regions. The combination approach developed in this study has the potential to be applied to existing microwave satellites as well as to new microwave missions. Accordingly, a long-term global soil moisture dataset can be developed and extended, enhancing basic understanding of the role of soil moisture in the water, energy and carbon cycles.

  3. Categorizing natural disaster damage assessment using satellite-based geospatial techniques

    Science.gov (United States)

    Myint, S.W.; Yuan, M.; Cerveny, R.S.; Giri, C.

    2008-01-01

    Remote sensing of a natural disaster's damage offers an exciting backup and/or alternative to traditional means of on-site damage assessment. Although necessary for complete assessment of damage areas, ground-based damage surveys conducted in the aftermath of natural hazard passage can sometimes be potentially complicated due to on-site difficulties (e.g., interaction with various authorities and emergency services) and hazards (e.g., downed power lines, gas lines, etc.), the need for rapid mobilization (particularly for remote locations), and the increasing cost of rapid physical transportation of manpower and equipment. Satellite image analysis, because of its global ubiquity, its ability for repeated independent analysis, and, as we demonstrate here, its ability to verify on-site damage assessment provides an interesting new perspective and investigative aide to researchers. Using one of the strongest tornado events in US history, the 3 May 1999 Oklahoma City Tornado, as a case example, we digitized the tornado damage path and co-registered the damage path using pre- and post-Landsat Thematic Mapper image data to perform a damage assessment. We employed several geospatial approaches, specifically the Getis index, Geary's C, and two lacunarity approaches to categorize damage characteristics according to the original Fujita tornado damage scale (F-scale). Our results indicate strong relationships between spatial indices computed within a local window and tornado F-scale damage categories identified through the ground survey. Consequently, linear regression models, even incorporating just a single band, appear effective in identifying F-scale damage categories using satellite imagery. This study demonstrates that satellite-based geospatial techniques can effectively add spatial perspectives to natural disaster damages, and in particular for this case study, tornado damages.

  4. A method to develop mission critical data processing systems for satellite based instruments. The spinning mode case

    CERN Document Server

    Lazzarotto, Francesco; Costa, Enrico; Del Monte, Ettore; Di Persio, Giuseppe; Donnarumma, Immacolata; Evangelista, Yuri; Feroci, Marco; Pacciani, Luigi; Rubini, Alda; Soffitta, Paolo

    2011-01-01

    Modern satellite based experiments are often very complex real-time systems, composed by flight and ground segments, that have challenging resource related constraints, in terms of size, weight, power, requirements for real-time response, fault tolerance, and specialized input/output hardware-software, and they must be certified to high levels of assurance. Hardware-software data processing systems have to be responsive to system degradation and to changes in the data acquisition modes, and actions have to be taken to change the organization of the mission operations. A big research & develop effort in a team composed by scientists and technologists can lead to produce software systems able to optimize the hardware to reach very high levels of performance or to pull degraded hardware to maintain satisfactory features. We'll show real-life examples describing a system, processing the data of a X-Ray detector on satellite-based mission in spinning mode.

  5. Assessing the utility of satellite-based whitecap fraction to estimate sea spray production and CO2 transfer velocity

    Science.gov (United States)

    Anguelova, M. D.

    2016-05-01

    The utility of a satellite-based whitecap database for estimates of surface sea spray production and bubble-mediated gas transfer on a global scale is presented. Existing formulations of sea spray production and bubble-mediated CO2 transfer velocity involve whitecap fraction parametrization as a function of wind speed at 10 m reference height W(U 10) based on photographic measurements of whitecaps. Microwave radiometric measurements of whitecaps from satellites provide whitecap fraction data over the world oceans for all seasons. Parametrizations W(U 10) based on such radiometric data are thus applicable for a wide range of conditions and can account for influences secondary to the primary forcing factor, the wind speed. Radiometric satellite-based W(U 10) relationship was used as input to: (i) the Coupled Ocean-Atmosphere Response Experiment Gas transfer (COAREG) algorithm to obtain CO2 transfer velocity and total CO2 flux; and (ii) the sea spray source function (SSSF) recommended by Andreas in 2002 to obtain fluxes of sea spray number and mass. The outputs of COAREG and SSSF obtained with satellite-based W(U 10) are compared with respective outputs obtained with the nominal W(U 10) relationship based on photographic data. Good comparisons of the gas and sea spray fluxes with direct measurements and previous estimates imply that the satellite- based whitecap database can be useful to obtain surface fluxes of particles and gases in regions and conditions difficult to access and sample in situ. Satellite and in situ estimates of surface sea spray production and bubble-mediated gas transfer thus complement each other: accurate in situ observations can constrain radiometric whitecap fraction and mass flux estimates, while satellite observations can provide global coverage of whitecap fraction and mass flux estimates.

  6. Comparison of Historical Satellite-Based Estimates of Solar Radiation Resources with Recent Rotating Shadowband Radiometer Measurements: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Myers, D. R.

    2009-03-01

    The availability of rotating shadow band radiometer measurement data at several new stations provides an opportunity to compare historical satellite-based estimates of solar resources with measurements. We compare mean monthly daily total (MMDT) solar radiation data from eight years of NSRDB and 22 years of NASA hourly global horizontal and direct beam solar estimates with measured data from three stations, collected after the end of the available resource estimates.

  7. Pixel Intensity Based Cumulative Features for Moving Object Tracking (MOT) in Darkness

    Science.gov (United States)

    Saba, Tanzila

    2016-06-01

    Moving Object Tracking (MOT) is one of the frequent used tasks in computer vision systems and on the same time a challenging issue particularly in darkness. Vehicle tracking involves finding new position of vehicles in consecutive frames. This paper presents MOT algorithm that is developed for advanced driver safety applications like automatic high beam control, forward collision warning. Accordingly, the proposed approach targets vehicle tracking in the dark environment. Hence, a camera is mounted on the host vehicle to capture video frames of the traffic ahead. The scope involves tracking of both oncoming and preceding vehicles. The vehicles are tracked in consecutive frames using grayscale information and robust structure features. The features representation of the vehicle region is based on cumulative pixel intensity information. The implementation for feature extraction is optimized by using a dynamic programming approach to meet the constraints of a real time application. Simulation results thus obtained are promising in state of the art.

  8. Navigation and control of an autonomous vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Simon, A.; Soehnitz, I.; Becker, J.C.; Schumacher, W. [Technical Univ. Braunschweig (Germany). Inst. of Control Engineering

    2000-07-01

    This paper describes the fusion of sensor data for the navigation of an autonomous vehicle as well as two lateral control concepts to track the vehicle along a desired path. The fusion of navigation data is based on information provided by multiple object-detecting sensors. The object data is fused to increase the accuracy and to obtain the vehicle's state from the relative movement w.r.t. the objects. The presented lateral control methods are an LQG/H{sub 2}-design and an input-output linearizing algorithm. These control schemes were both implemented on a test vehicle. (orig.)

  9. Abandoned vehicles

    CERN Multimedia

    Relations with the Host States Service

    2004-01-01

    The services in charge of managing the CERN site have recently noted an increase in the number of abandoned vehicles. This poses a risk from the point of view of safety and security and, on the eve of several important events in honour of CERN's fiftieth anniversary, is detrimental to the Organization's image. Owners of vehicles that have been left immobile for some time on the CERN site, including on the external car park by the flags, are therefore invited to contact the Reception and Access Control Service (service-parking-longterm@cern.ch) before 1st October 2004 and, where appropriate, move their vehicle to a designated long-term parking area. After this date, any vehicle whose owner has failed to respond to this request and which is without a number plate, has been stationary for several weeks or is out of service, may be impounded at the owner's risk and expense. Relations with the Host States Service Tel. 72848

  10. Adaptive vehicle motion estimation and prediction

    Science.gov (United States)

    Zhao, Liang; Thorpe, Chuck E.

    1999-01-01

    Accurate motion estimation and reliable maneuver prediction enable an automated car to react quickly and correctly to the rapid maneuvers of the other vehicles, and so allow safe and efficient navigation. In this paper, we present a car tracking system which provides motion estimation, maneuver prediction and detection of the tracked car. The three strategies employed - adaptive motion modeling, adaptive data sampling, and adaptive model switching probabilities - result in an adaptive interacting multiple model algorithm (AIMM). The experimental results on simulated and real data demonstrate that our tracking system is reliable, flexible, and robust. The adaptive tracking makes the system intelligent and useful in various autonomous driving tasks.

  11. Selection of the best initial orbital elements of satellite based on fuzzy integration evaluation method

    Institute of Scientific and Technical Information of China (English)

    Yang Yong'an; Zhang Hongwei; Feng Zuren; Luo Yongjin

    2006-01-01

    The fuzzy integration evaluation method (FIEM) is studied in order to select the best orbital elements from the multi-group initial orbits determined by a satellite TT&C (Tracking, Telemetry and Control) center with all kinds of data sources. By employing FIEM together with the experience of TT&C experts, the index system to evaluate the selection of the best initial orbits is established after the data sources and orbit determination theories are studied. Besides, the concrete steps in employing the method are presented. Moreover, by taking the objects to be evaluated as evaluation experts, the problem of how to generate evaluation matrices is solved. Through practical application, the method to select the best initial orbital elements has been proved to be flexible and effective. The originality of the method is to find a new evaluation criterion (comparing the actually tracked orbits) replacing the traditional one (comparing the nominal orbits) for selecting the best orbital elements.

  12. Satellite based Observations of Saharan Dust Source Areas - Comparison and Variability

    Science.gov (United States)

    Schepanski, K.; Tegen, I.; Macke, A.

    2012-04-01

    Satellite remote sensing products such as Meteosat Second Generation (MSG) Infra Red (IR) dust index and Ozone Monitoring Instrument (OMI) Aerosol Index (AI) are commonly used to infer dust source areas. We compare two different methods for dust source identification, (1) a "back-tacking" method applied to 4 years of 15-minute MSG IR dust index, and (2) a "frequency" method applied to daily OMI AI and daily MODIS DeepBlue Aerosol Optical Thickness (AOT) data for the same time period. Using the "back-tracking" method, dust source areas are inferred by tracking individual dust plumes back to their place of origin, allowed by the high temporal resolution of the MSG images. OMI AI and MODIS Deep Blue AOT products are available on daily resolution only, which disables for back-tracking of individual dust plumes. Thus, dust source areas are retrieved by relating the frequencies of occurrence of high dust loadings to source areas. The spatial distribution of inferred dust source areas from the two methods shows significant differences. The MSG back-tracking method highlights frequent dust emission from sources within complex terrain, while frequencies of high OMI AI values emphasise topographic basins as important dust source areas. Dust source areas retrieved from DeepBlue AOTs are generally placed further south towards the Sahel region. This study shows that the temporal resolution of satellite dust products is a key issue in retrieving dust source areas. Both, the spatial distribution of dust sources and their annual cycle strongly depend on the acquisition time related to the start of dust emission.

  13. Magnetic Launch Assist Vehicle-Artist's Concept

    Science.gov (United States)

    1999-01-01

    This artist's concept depicts a Magnetic Launch Assist vehicle clearing the track and shifting to rocket engines for launch into orbit. The system, formerly referred as the Magnetic Levitation (MagLev) system, is a launch system developed and tested by Engineers at the Marshall Space Flight Center (MSFC) that could levitate and accelerate a launch vehicle along a track at high speeds before it leaves the ground. Using an off-board electric energy source and magnetic fields, a Magnetic Launch Assist system would drive a spacecraft along a horizontal track until it reaches desired speeds. The system is similar to high-speed trains and roller coasters that use high-strength magnets to lift and propel a vehicle a couple of inches above a guideway. A full-scale, operational track would be about 1.5-miles long, capable of accelerating a vehicle to 600 mph in 9.5 seconds, and the vehicle would then shift to rocket engines for launch into orbit. The major advantages of launch assist for NASA launch vehicles is that it reduces the weight of the take-off, the landing gear, the wing size, and less propellant resulting in significant cost savings. The US Navy and the British MOD (Ministry of Defense) are planning to use magnetic launch assist for their next generation aircraft carriers as the aircraft launch system. The US Army is considering using this technology for launching target drones for anti-aircraft training.

  14. Using R for analysing spatio-temporal datasets: a satellite-based precipitation case study

    Science.gov (United States)

    Zambrano-Bigiarini, Mauricio

    2017-04-01

    Increasing computer power and the availability of remote-sensing data measuring different environmental variables has led to unprecedented opportunities for Earth sciences in recent decades. However, dealing with hundred or thousands of files, usually in different vectorial and raster formats and measured with different temporal frequencies, impose high computation challenges to take full advantage of all the available data. R is a language and environment for statistical computing and graphics which includes several functions for data manipulation, calculation and graphical display, which are particularly well suited for Earth sciences. In this work I describe how R was used to exhaustively evaluate seven state-of-the-art satellite-based rainfall estimates (SRE) products (TMPA 3B42v7, CHIRPSv2, CMORPH, PERSIANN-CDR, PERSIAN-CCS-adj, MSWEPv1.1 and PGFv3) over the complex topography and diverse climatic gradients of Chile. First, built-in functions were used to automatically download the satellite-images in different raster formats and spatial resolutions and to clip them into the Chilean spatial extent if necessary. Second, the raster package was used to read, plot, and conduct an exploratory data analysis in selected files of each SRE product, in order to detect unexpected problems (rotated spatial domains, order or variables in NetCDF files, etc). Third, raster was used along with the hydroTSM package to aggregate SRE files into different temporal scales (daily, monthly, seasonal, annual). Finally, the hydroTSM and hydroGOF packages were used to carry out a point-to-pixel comparison between precipitation time series measured at 366 stations and the corresponding grid cell of each SRE. The modified Kling-Gupta index of model performance was used to identify possible sources of systematic errors in each SRE, while five categorical indices (PC, POD, FAR, ETS, fBIAS) were used to assess the ability of each SRE to correctly identify different precipitation intensities

  15. Satellite-based monitoring of particulate matter pollution at very high resolution: the HOTBAR method

    Science.gov (United States)

    Wilson, Robin; Milton, Edward; Nield, Joanna

    2016-04-01

    Particulate matter air pollution is a major health risk, and is responsible for millions of premature deaths each year. Concentrations tend to be highest in urban areas - particularly in the mega-cities of rapidly industrialising countries, where there are limited ground monitoring networks. Satellite-based monitoring has been used for many years to assess regional-scale trends in air quality, but currently available satellite products produce data at 1-10km resolution: too coarse to discern the small-scale patterns of sources and sinks seen in urban areas. Higher-resolution satellite products are required to provide accurate assessments of particulate matter concentrations in these areas, and to allow analysis of localised air quality effects on health. The Haze Optimized Transform-based Aerosol Retrieval (HOTBAR) method is a novel method which provides estimates of PM2.5 concentrations from high-resolution (approximately 30m) satellite imagery. This method is designed to work over a wide range of land covers and performs well over the complex land-cover mosaic found in urban areas. It requires only standard visible and near-infrared data, making it applicable to a range of data from sensors such as Landsat, SPOT and Sentinel-2. The method is based upon an extension of the Haze Optimized Transform (HOT), which was originally designed for assessing areas of thick haze in satellite imagery. This was done by calculating a 'haziness' value for each pixel in an image as the distance from a 'Clear Line' in feature space, defined by the high correlation between visible bands. Here, we adapt the HOT method and use it to estimate Aerosol Optical Thickness (a measure of the column-integrated haziness of the atmosphere) instead, from which PM2.5 concentrations can then be estimated. Significant extensions to the original HOT method include Monte Carlo estimation of the 'Clear Line', object-based correction for land cover, and estimation of AOT from the haziness values

  16. Utility and Value of Satellite-Based Frost Forecasting for Kenya's Tea Farming Sector

    Science.gov (United States)

    Morrison, I.

    2016-12-01

    Frost damage regularly inflicts millions of dollars of crop losses in the tea-growing highlands of western Kenya, a problem that the USAID/NASA Regional Visualization and Monitoring System (SERVIR) program is working to mitigate through a frost monitoring and forecasting product that uses satellite-based temperature and soil moisture data to generate up to three days of advanced warning before frost events. This paper presents the findings of a value of information (VOI) study assessing the value of this product based on Kenyan tea farmers' experiences with frost and frost-damage mitigation. Value was calculated based on historic trends of frost frequency, severity, and extent; likelihood of warning receipt and response; and subsequent frost-related crop-loss aversion. Quantification of these factors was derived through inferential analysis of survey data from 400 tea-farming households across the tea-growing regions of Kericho and Nandi, supplemented with key informant interviews with decision-makers at large estate tea plantations, historical frost incident and crop-loss data from estate tea plantations and agricultural insurance companies, and publicly available demographic and economic data. At this time, the product provides a forecasting window of up to three days, and no other frost-prediction methods are used by the large or small-scale farmers of Kenya's tea sector. This represents a significant opportunity for preemptive loss-reduction via Earth observation data. However, the tea-growing community has only two realistic options for frost-damage mitigation: preemptive harvest of available tea leaves to minimize losses, or skiving (light pruning) to facilitate fast recovery from frost damage. Both options are labor-intensive and require a minimum of three days of warning to be viable. As a result, the frost forecasting system has a very narrow margin of usefulness, making its value highly dependent on rapid access to the warning messages and flexible access

  17. The development of potassium tantalate niobate thin films for satellite-based pyroelectric detectors

    Energy Technology Data Exchange (ETDEWEB)

    Cherry, Hilary B.B. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

    1997-05-01

    Potassium tantalate niobate (KTN) pyroelectric detectors are expected to provide detectivities, of 3.7 x 1011 cmHz 1/2W-1 for satellite-based infrared detection at 90 K. The background limited detectivity for a room-temperature thermal detector is 1.8 x 1010 cmHz1/2W-1 . KTN is a unique ferroelectric for this application because of the ability to tailor the temperature of its pyroelectric response by adjusting its ratio of tantalum to niobium. The ability to fabricate high quality KTN thin films on Si-based substrates is crucial to the development of KTN pyroelectric detectors. SixNymembranes created on the Si substrate will provide the weak thermal link necessary to reach background limited detectivities. The device dimensions obtainable by thin film processing are expected to increase the ferroelectric response by 20 times over bulk fabricated KTN detectors. In addition, microfabrication techniques allow for easier array development. This is the first reported attempt at growth of KTN films on Si-based substrates. Pure phase perovskite films were grown by pulsed laser deposition on SrRuO3/Pt/Ti/SixNy/Si and SrRuO3/SixNy/Si structures; room temperature dielectric permittivities for the KTN films were 290 and 2.5, respectively. The dielectric permittivity for bulk grown, single crystal KTN is ~380. In addition to depressed dielectric permittivities, no ferroelectric hysteresis was found between 80 and 300 K for either structure. RBS, AES, TEM and multi-frequency dielectric measurements were used to investigate the origin of this apparent lack of ferroelectricity. Other issues addressed by this dissertation include: the role of oxygen and target density during pulsed laser deposition of KTN thin films; the use of YBCO, LSC and Pt as direct contact bottom electrodes to the KTN films, and the adhesion of the bottom

  18. Assessment of Satellite-based Precipitation Products (TRMM) in Hydrologic Modeling: Case Studies from Northern Morocco

    Science.gov (United States)

    EL kadiri, R.; Milewski, A.; Durham, M.

    2012-12-01

    Precipitation is the most important forcing parameter in hydrological modeling, yet it is largely unknown in the arid Middle East. We assessed the magnitude, probability of detection, and false alarm rates of various rainfall satellite products (e.g., TRMM, RFE2.0) compared to in situ gauge data (~79 stations) across the Our Er Rbia, Sebou, and Melouya Watersheds in Northern Morocco. Precipitation over the area is relatively high with an average of ~400mm/year according to TRMM (1998-2008). The existing gauges indicate that the average annual precipitation across the Tadla and Coastal Plains region is 260mm/year and 390mm/year across the Atlas Mountains. Following the assessment of satellite products against in situ gauge data, we evaluated the effects (e.g., runoff and recharge amounts) of using satellite driven hydrologic models using SWAT. Specifically, we performed a four-fold exercise: (1) The first stage focused on the analysis of the rainfall products; (2) the second stage involved the construction of a rainfall-runoff model using gauge data; (3) the third stage entailed the calibration of the model against flow gauges and/or dams storage variability, and (4) model simulation using satellite based rainfall products using the calibrated parameters from the initial simulation. Results suggest the TRMM V7 has a much better correlation with the field data over the Oum Er Rbia watershed. The Correlation E (Nash-Suncliffe coefficient) has a positive value of 0.5, while the correlation coefficient of TRMM V6 vs. gauges data is a negative value of -0.25. This first order evaluation of the TRMM V7 shows the new algorithm has partially overcame the underestimation effect in the semi-arid environments. However, more research needs to be done to increase the usability of TRMM V7 in hydrologic models. Low correlations are most likely a result of the following: (1) snow at the high elevations in the Oum Er Rbia watershed, (2) the ocean effect on TRMM measurements along

  19. Satellite-based Estimates of Ambient Air Pollution and Global Variations in Childhood Asthma Prevalence

    Science.gov (United States)

    Anderson, H. Ross; Butland, Barbara K.; Donkelaar, Aaron Matthew Van; Brauer, Michael; Strachan, David P.; Clayton, Tadd; van Dingenen, Rita; Amann, Marcus; Brunekreef, Bert; Cohen, Aaron; Dentener, Frank; Lai, Christopher; Lamsal, Lok N.; Martin, Randall V.

    2012-01-01

    Background: The effect of ambient air pollution on global variations and trends in asthma prevalence is unclear. Objectives: Our goal was to investigate community-level associations between asthma prevalence data from the International Study of Asthma and Allergies in Childhood (ISAAC) and satellite-based estimates of particulate matter with aerodynamic diameter prevalence of severe asthma as the outcome and multilevel models to adjust for gross national income (GNI) and center- and country-level sex, climate, and population density. We examined associations (adjusting for GNI) between air pollution and asthma prevalence over time in centers with data from ISAAC Phase One (mid-1900s) and Phase Three (2001-2003). Results: For the 13- to 14-year age group (128 centers in 28 countries), the estimated average within-country change in center-level asthma prevalence per 100 children per 10% increase in center-level PM2.5 and NO2 was -0.043 [95% confidence interval (CI): -0.139, 0.053] and 0.017 (95% CI: -0.030, 0.064) respectively. For ozone the estimated change in prevalence per parts per billion by volume was -0.116 (95% CI: -0.234, 0.001). Equivalent results for the 6- to 7-year age group (83 centers in 20 countries), though slightly different, were not significantly positive. For the 13- to 14-year age group, change in center-level asthma prevalence over time per 100 children per 10% increase in PM2.5 from Phase One to Phase Three was -0.139 (95% CI: -0.347, 0.068). The corresponding association with ozone (per ppbV) was -0.171 (95% CI: -0.275, -0.067). Conclusion: In contrast to reports from within-community studies of individuals exposed to traffic pollution, we did not find evidence of a positive association between ambient air pollution and asthma prevalence as measured at the community level.

  20. Advanced Oil Spill Detection Algorithms For Satellite Based Maritime Environment Monitoring

    Science.gov (United States)

    Radius, Andrea; Azevedo, Rui; Sapage, Tania; Carmo, Paulo

    2013-12-01

    During the last years, the increasing pollution occurrence and the alarming deterioration of the environmental health conditions of the sea, lead to the need of global monitoring capabilities, namely for marine environment management in terms of oil spill detection and indication of the suspected polluter. The sensitivity of Synthetic Aperture Radar (SAR) to the different phenomena on the sea, especially for oil spill and vessel detection, makes it a key instrument for global pollution monitoring. The SAR performances in maritime pollution monitoring are being operationally explored by a set of service providers on behalf of the European Maritime Safety Agency (EMSA), which has launched in 2007 the CleanSeaNet (CSN) project - a pan-European satellite based oil monitoring service. EDISOFT, which is from the beginning a service provider for CSN, is continuously investing in R&D activities that will ultimately lead to better algorithms and better performance on oil spill detection from SAR imagery. This strategy is being pursued through EDISOFT participation in the FP7 EC Sea-U project and in the Automatic Oil Spill Detection (AOSD) ESA project. The Sea-U project has the aim to improve the current state of oil spill detection algorithms, through the informative content maximization obtained with data fusion, the exploitation of different type of data/ sensors and the development of advanced image processing, segmentation and classification techniques. The AOSD project is closely related to the operational segment, because it is focused on the automation of the oil spill detection processing chain, integrating auxiliary data, like wind information, together with image and geometry analysis techniques. The synergy between these different objectives (R&D versus operational) allowed EDISOFT to develop oil spill detection software, that combines the operational automatic aspect, obtained through dedicated integration of the processing chain in the existing open source NEST

  1. Comparison of Satellite-based Basal and Adjusted Evapotranspiration for Several California Crops

    Science.gov (United States)

    Johnson, L.; Lund, C.; Melton, F. S.

    2013-12-01

    _adj throughout each monitoring period was lower than cumulative ETb for most crops, indicating that effect of water stress tended to exceed that of soil evaporation relative to basal conditions. We present results from the analysis and discuss implications for operational use of satellite-based Kcb and ETcb estimates for agricultural water resource management.

  2. The development of potassium tantalate niobate thin films for satellite-based pyroelectric detectors

    Energy Technology Data Exchange (ETDEWEB)

    Cherry, H B.B. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

    1997-05-01

    Potassium tantalate niobate (KTN) pyroelectric detectors are expected to provide detectivities, of 3.7 x 10{sup 11} cmHz {sup {1/2}}W{sup {minus}1} for satellite-based infrared detection at 90 K. The background limited detectivity for a room-temperature thermal detector is 1.8 x 10{sup 10} cmHz{sup {1/2}}W{sup {minus}1}. KTN is a unique ferroelectric for this application because of the ability to tailor the temperature of its pyroelectric response by adjusting its ratio of tantalum to niobium. The ability to fabricate high quality KTN thin films on Si-based substrates is crucial to the development of KTN pyroelectric detectors. Si{sub x}N{sub y} membranes created on the Si substrate will provide the weak thermal link necessary to reach background limited detectivities. The device dimensions obtainable by thin film processing are expected to increase the ferroelectric response by 20 times over bulk fabricated KTN detectors. In addition, microfabrication techniques allow for easier array development. This is the first reported attempt at growth of KTN films on Si-based substrates. Pure phase perovskite films were grown by pulsed laser deposition on SrRuO{sub 3}/Pt/Ti/Si{sub x}N{sub y}/Si and SrRuO{sub 3}/Si{sub x}N{sub y}/Si structures; room temperature dielectric permittivities for the KTN films were 290 and 2.5, respectively. The dielectric permittivity for bulk grown, single crystal KTN is {approximately}380. In addition to depressed dielectric permittivities, no ferroelectric hysteresis was found between 80 and 300 K for either structure. RBS, AES, TEM and multi-frequency dielectric measurements were used to investigate the origin of this apparent lack of ferroelectricity. Other issues addressed by this dissertation include: the role of oxygen and target density during pulsed laser deposition of KTN thin films; the use of YBCO, LSC and Pt as direct contact bottom electrodes to the KTN films, and the adhesion of the bottom electrode layers to Si{sub x}N{sub y}/Si.

  3. The Satellite Based Hydrological Model (SHM): Routing Scheme and its Evaluation

    Science.gov (United States)

    kumari, Nikul; Paul, Pranesh Kumar; Singh, Rajendra; Panigrahy, Niranjan; Mishra, Ashok; Gupta, Praveen Kumar; Singh, Raghavendra P.

    2016-04-01

    The collection of spatially extensive data by using the traditional methods of data acquisition is a challenging task for a large territory like India. To overcome such problems, the Satellite based Hydrological Model (SHM), a large scale conceptual hydrological model for the Indian Territory, is being developed under the PRACRITI-2 program of the Space Applications Centre (SAC), Ahmedabad. The model aims at preparing sustainable water management scenarios using remote sensing data from Indian satellites to handle the fresh water crisis in India. There are five modules namely, Surface Water (SW), Forest (F), Snow (S), Groundwater (GW) and Routing (ROU) in the SHM. The SW, F and S modules convert rainfall into surface runoff and generate input (infiltration and percolation) for the GW module, and GW generates baseflow using that input. In this study, a cell-to-cell routing (ROU) module has been developed for SHM. It is based on the principle of Time Variant Spatially Distributed Direct Hydrograph (SDDH) to route the generated runoff and baseflow generated by various modules upto the outlet. The entire India is divided into 5km x 5km grid cells and properties at the center of the cell are assumed to represent the property of the cell. In the routing scheme, for each cell a single downstream cell is defined in the direction of steepest descent, to create the flow network. These grid cells are classified into overland cells and channel cells based on the threshold value taken into consideration. The overland flow travel time of each overland cell is estimated by combining a steady state kinematic wave approximation with Manning's equation and the channel flow travel time of each channel cell is estimated using Manning's equation and the steady state continuity equation. The travel time for each cell is computed by dividing the travel distance through that cell with cell velocity. The cumulative travel time from each grid cell to the watershed outlet is the sum of

  4. Satellite-based assessment of climate controls on US burned area

    Directory of Open Access Journals (Sweden)

    D. C. Morton

    2013-01-01

    Full Text Available Climate regulates fire activity through the buildup and drying of fuels and the conditions for fire ignition and spread. Understanding the dynamics of contemporary climate–fire relationships at national and sub-national scales is critical to assess the likelihood of changes in future fire activity and the potential options for mitigation and adaptation. Here, we conducted the first national assessment of climate controls on US fire activity using two satellite-based estimates of monthly burned area (BA, the Global Fire Emissions Database (GFED, 1997–2010 and Monitoring Trends in Burn Severity (MTBS, 1984–2009 BA products. For each US National Climate Assessment (NCA region, we analyzed the relationships between monthly BA and potential evaporation (PE derived from reanalysis climate data at 0.5° resolution. US fire activity increased over the past 25 yr, with statistically significant increases in MTBS BA for the entire US and the Southeast and Southwest NCA regions. Monthly PE was strongly correlated with US fire activity, yet the climate driver of PE varied regionally. Fire season temperature and shortwave radiation were the primary controls on PE and fire activity in Alaska, while water deficit (precipitation – PE was strongly correlated with fire activity in the Plains regions and Northwest US. BA and precipitation anomalies were negatively correlated in all regions, although fuel-limited ecosystems in the Southern Plains and Southwest exhibited positive correlations with longer lead times (6–12 months. Fire season PE increased from the 1980's–2000's, enhancing climate-driven fire risk in the southern and western US where PE–BA correlations were strongest. Spatial and temporal patterns of increasing fire season PE and BA during the 1990's–2000's highlight the potential sensitivity of US fire activity to climate change in coming decades. However, climate-fire relationships at the national scale are complex, based on the

  5. Satellite-based assessment of climate controls on US burned area

    Directory of Open Access Journals (Sweden)

    D. C. Morton

    2012-06-01

    Full Text Available Climate regulates fire activity through the buildup and drying of fuels and the conditions for fire ignition and spread. Understanding the dynamics of contemporary climate-fire relationships at national and sub-national scales is critical to assess the likelihood of changes in future fire activity and the potential options for mitigation and adaptation. Here, we conducted the first national assessment of climate controls on US fire activity using two satellite-based estimates of monthly burned area (BA, the Global Fire Emissions Database (GFED, 1997–2010 and Monitoring Trends in Burn Severity (MTBS, 1984–2009 BA products. For each US National Climate Assessment (NCA region, we analyzed the relationships between monthly BA and potential evaporation (PE derived from reanalysis climate data at 0.5° resolution. US fire activity increased over the past 25 yr, with statistically significant increases in MTBS BA for entire US and the Southeast and Southwest NCA regions. Monthly PE was strongly correlated with US fire activity, yet the climate driver of PE varied regionally. Fire season temperature and shortwave radiation were the primary controls on PE} and fire activity in the Alaska, while water deficit (precipitation – PE was strongly correlated with fire activity in the Plains regions and Northwest US. BA and precipitation anomalies were negatively correlated in all regions, although fuel-limited ecosystems in the Southern Plains and Southwest exhibited positive correlations with longer lead times (6–12 months. Fire season PE increased from the 1980s–2000s, enhancing climate-driven fire risk in the southern and western US where PE-BA correlations were strongest. Spatial and temporal patterns of increasing fire season PE and BA during the 1990s–2000s highlight the potential sensitivity of US fire activity to climate change in coming decades. However, climate-fire relationships at the national scale are complex, based on the diversity of

  6. Satellite-based assessment of climate controls on US burned area

    Science.gov (United States)

    Morton, D. C.; Collatz, G. J.; Wang, D.; Randerson, J. T.; Giglio, L.; Chen, Y.

    2013-01-01

    Climate regulates fire activity through the buildup and drying of fuels and the conditions for fire ignition and spread. Understanding the dynamics of contemporary climate-fire relationships at national and sub-national scales is critical to assess the likelihood of changes in future fire activity and the potential options for mitigation and adaptation. Here, we conducted the first national assessment of climate controls on US fire activity using two satellite-based estimates of monthly burned area (BA), the Global Fire Emissions Database (GFED, 1997-2010) and Monitoring Trends in Burn Severity (MTBS, 1984-2009) BA products. For each US National Climate Assessment (NCA) region, we analyzed the relationships between monthly BA and potential evaporation (PE) derived from reanalysis climate data at 0.5° resolution. US fire activity increased over the past 25 yr, with statistically significant increases in MTBS BA for the entire US and the Southeast and Southwest NCA regions. Monthly PE was strongly correlated with US fire activity, yet the climate driver of PE varied regionally. Fire season temperature and shortwave radiation were the primary controls on PE and fire activity in Alaska, while water deficit (precipitation - PE) was strongly correlated with fire activity in the Plains regions and Northwest US. BA and precipitation anomalies were negatively correlated in all regions, although fuel-limited ecosystems in the Southern Plains and Southwest exhibited positive correlations with longer lead times (6-12 months). Fire season PE increased from the 1980's-2000's, enhancing climate-driven fire risk in the southern and western US where PE-BA correlations were strongest. Spatial and temporal patterns of increasing fire season PE and BA during the 1990's-2000's highlight the potential sensitivity of US fire activity to climate change in coming decades. However, climate-fire relationships at the national scale are complex, based on the diversity of fire types

  7. Predicting Mobility Performance of a Small, Lightweight Track System Using the Computer-Aided Method NTVPM

    Science.gov (United States)

    2015-04-24

    track system on sandy soil. The cross-country (tractive) performance of the track system predicted by NTVPM is compared with experimental data obtained...of large, heavy tracked vehicles (Wong, 2008; Wong 2010), to predicting the performance of a small, lightweight single track system on sandy soil...and the sprocket at the rear. The track is made of rubber (a 92 shore A durometer toothed rubber belt produced by BrecoFlex). The track (belt) width

  8. Dynamic analysis of rail transit elevated bridge with ladder track

    Institute of Scientific and Technical Information of China (English)

    He XIA; Yushu DENG; Yongwei ZOU; Guido DE ROECK; Geert DEGRANDE

    2009-01-01

    In this paper, a dynamic analysis model of an elevated bridge with ladder tracks under moving train load is established. The whole process of a train running through an elevated bridge at different speeds is simulated.The dynamic responses of the elevated bridge with ladder track and the running safety and comfort index of train vehicles are evaluated. Compared with the dynamic responses of an elevated bridge with ordinary non-ballasted slab track, the ladder track's effect on reducing the vibration of an elevated bridge is analyzed. The analysis results show that the ladder track has good vibration reduction characteristics as compared to ordinary non-ballasted track.

  9. Hermes vehicle

    Science.gov (United States)

    Cretenet, J. C.

    1985-11-01

    The presence of Europe in the future developments of spatial programs, which are foreseen, for the 1990s and further, needs the availability of vehicles, modules and all related technologies adapted to operational use of low earth orbit station. The manned HERMES vehicle shall be part of the in-orbit infrastructure realized either in the European context or in cooperation between Europe and the United States. The main mission for this vehicle will be to run a shuttle with the station that means transport and change of the crews, its safe return in abort condition and cargo transport of consumable and experimental equipment. Secondary missions could be servicing on automatic platform, making autonomous scientific experiments. Lastly, the vehicle, by means of its on-board propulsion capability, could be used to accomplish in-orbit tow and assembly missions. Studies which are undertaken now about the vehicle are devoted to the aerodynamic shape (research of a compromise between aerothermic and overall fitting), the system (functional architecture, ground and flight configuration); further works dealing with technology are presently on hand in the field of thermal protection, aerodynamics, power generation with a high massic yield.

  10. electric vehicle

    Directory of Open Access Journals (Sweden)

    W. R. Lee

    1999-01-01

    Full Text Available A major problem facing battery-powered electric vehicles is in their batteries: weight and charge capacity. Thus, a battery-powered electric vehicle only has a short driving range. To travel for a longer distance, the batteries are required to be recharged frequently. In this paper, we construct a model for a battery-powered electric vehicle, in which driving strategy is to be obtained such that the total travelling time between two locations is minimized. The problem is formulated as an optimization problem with switching times and speed as decision variables. This is an unconventional optimization problem. However, by using the control parametrization enhancing technique (CPET, it is shown that this unconventional optimization is equivalent to a conventional optimal parameter selection problem. Numerical examples are solved using the proposed method.

  11. Railway vehicle performance optimisation using virtual homologation

    Science.gov (United States)

    Magalhães, H.; Madeira, J. F. A.; Ambrósio, J.; Pombo, J.

    2016-09-01

    Unlike regular automotive vehicles, which are designed to travel in different types of roads, railway vehicles travel mostly in the same route during their life cycle. To accept the operation of a railway vehicle in a particular network, a homologation process is required according to local standard regulations. In Europe, the standards EN 14363 and UIC 518, which are used for railway vehicle acceptance, require on-track tests and/or numerical simulations. An important advantage of using virtual homologation is the reduction of the high costs associated with on-track tests by studying the railway vehicle performance in different operation conditions. This work proposes a methodology for the improvement of railway vehicle design with the objective of its operation in selected railway tracks by using optimisation. The analyses required for the vehicle improvement are performed under control of the optimisation method global and local optimisation using direct search. To quantify the performance of the vehicle, a new objective function is proposed, which includes: a Dynamic Performance Index, defined as a weighted sum of the indices obtained from the virtual homologation process; the non-compensated acceleration, which is related to the operational velocity; and a penalty associated with cases where the vehicle presents an unacceptable dynamic behaviour according to the standards. Thus, the optimisation process intends not only to improve the quality of the vehicle in terms of running safety and ride quality, but also to increase the vehicle availability via the reduction of the time for a journey while ensuring its operational acceptance under the standards. The design variables include the suspension characteristics and the operational velocity of the vehicle, which are allowed to vary in an acceptable range of variation. The results of the optimisation lead to a global minimum of the objective function in which the suspensions characteristics of the vehicle are

  12. Hybrid vehicles

    Energy Technology Data Exchange (ETDEWEB)

    West, J.G.W. [Electrical Machines (United Kingdom)

    1997-07-01

    The reasons for adopting hybrid vehicles result mainly from the lack of adequate range from electric vehicles at an acceptable cost. Hybrids can offer significant improvements in emissions and fuel economy. Series and parallel hybrids are compared. A combination of series and parallel operation would be the ideal. This can be obtained using a planetary gearbox as a power split device allowing a small generator to transfer power to the propulsion motor giving the effect of a CVT. It allows the engine to run at semi-constant speed giving better fuel economy and reduced emissions. Hybrid car developments are described that show the wide range of possible hybrid systems. (author)

  13. Japanese Global Precipitation Measurement (GPM) mission status and application of satellite-based global rainfall map

    Science.gov (United States)

    Kachi, Misako; Shimizu, Shuji; Kubota, Takuji; Yoshida, Naofumi; Oki, Riko; Kojima, Masahiro; Iguchi, Toshio; Nakamura, Kenji

    2010-05-01

    . Collaboration with GCOM-W is not only limited to its participation to GPM constellation but also coordination in areas of algorithm development and validation in Japan. Generation of high-temporal and high-accurate global rainfall map is one of targets of the GPM mission. As a proto-type for GPM era, JAXA has developed and operates the Global Precipitation Map algorithm in near-real-time since October 2008, and hourly and 0.1-degree resolution binary data and images available at http://sharaku.eorc.jaxa.jp/GSMaP/ four hours after observation. The algorithms are based on outcomes from the Global Satellite Mapping for Precipitation (GSMaP) project, which was sponsored by the Japan Science and Technology Agency (JST) under the Core Research for Evolutional Science and Technology (CREST) framework between 2002 and 2007 (Okamoto et al., 2005; Aonashi et al., 2009; Ushio et al., 2009). Target of GSMaP project is to produce global rainfall maps that are highly accurate and in high temporal and spatial resolution through the development of rain rate retrieval algorithms based on reliable precipitation physical models by using several microwave radiometer data, and comprehensive use of precipitation radar and geostationary infrared imager data. Near-real-time GSMaP data is distributed via internet and utilized by end users. Purpose of data utilization by each user covers broad areas and in world wide; Science researches (model validation, data assimilation, typhoon study, etc.), weather forecast/service, flood warning and rain analysis over river basin, oceanographic condition forecast, agriculture, and education. Toward the GPM era, operational application should be further emphasized as well as science application. JAXA continues collaboration with hydrological communities to utilize satellite-based precipitation data as inputs to future flood prediction and warning system, as well as with meteorological agencies to proceed further data utilization in numerical weather prediction

  14. Source mass eruption rate retrieved from satellite-based data using statistical modelling

    Science.gov (United States)

    Gouhier, Mathieu; Guillin, Arnaud; Azzaoui, Nourddine; Eychenne, Julia; Valade, Sébastien

    2015-04-01

    Ash clouds emitted during volcanic eruptions have long been recognized as a major hazard likely to have dramatic consequences on aircrafts, environment and people. Thus, the International Civil Aviation Organization (ICAO) established nine Volcanic Ash Advisory Centers (VAACs) around the world, whose mission is to forecast the location and concentration of ash clouds over hours to days, using volcanic ash transport and dispersion models (VATDs). Those models use input parameters such as plume height (PH), particle size distribution (PSD), and mass eruption rate (MER), the latter being a key parameter as it directly controls the amount of ash injected into the atmosphere. The MER can be obtained rather accurately from detailed ground deposit studies, but this method does not match the operational requirements in case of a volcanic crisis. Thus, VAACs use empirical laws to determine the MER from the estimation of the plume height. In some cases, this method can be difficult to apply, either because plume height data are not available or because uncertainties related to this method are too large. We propose here an alternative method based on the utilization of satellite data to assess the MER at the source, during explosive eruptions. Satellite-based techniques allow fine ash cloud loading to be quantitatively retrieved far from the source vent. Those measurements can be carried out in a systematic and real-time fashion using geostationary satellite, in particular. We tested here the relationship likely to exist between the amount of fine ash dispersed in the atmosphere and of coarser tephra deposited on the ground. The sum of both contributions yielding an estimate of the MER. For this purpose we examined 19 eruptions (of known duration) in detail for which both (i) the amount of fine ash dispersed in the atmosphere, and (ii) the mass of tephra deposited on the ground have been estimated and published. We combined these data with contextual information that may

  15. Assimilation of Satellite Based Soil Moisture Data in the National Weather Service's Flash Flood Guidance System

    Science.gov (United States)

    Seo, D.; Lakhankar, T.; Cosgrove, B.; Khanbilvardi, R.

    2012-12-01

    potential sources of remotely sensed soil moisture data. SMOS measures the microwave radiation emitted from the Earth's surface operating at L-band (1.20-1.41 GHz) to measure surface soil moisture directly. Microwave radiation at this wavelength offers relatively deeper penetration and has lower sensitivity to vegetation impacts. The main objective of this research is to evaluate the contribution of remote sensing technology to quantifiable improvements in flash flood applications as well as adding a remote sensing component to the NWS FFG Algorithm. The challenge of this study is employing the direct soil moisture data from SMOS to replace the model-calculated soil moisture state which is based on the soil water balance in 4 km x 4 km Hydrologic Rainfall Analysis Project (HRAP) grid cells. In order to determine the value of the satellite data to NWS operations, the streamflow generated by HL-RDHM with and without soil moisture assimilation will be compared to USGS gauge data. Furthermore, we will apply the satellite-based soil moisture data with the FFG algorithm to evaluate how many hits, misses and false alarms are generated. This study will evaluate the value of remote sensing data in constraining the state of the system for main-stem and flash flood forecasting.

  16. Evaluating the hydrological consistency of evaporation products using satellite-based gravity and rainfall data

    Science.gov (United States)

    López, Oliver; Houborg, Rasmus; McCabe, Matthew Francis

    2017-01-01

    Advances in space-based observations have provided the capacity to develop regional- to global-scale estimates of evaporation, offering insights into this key component of the hydrological cycle. However, the evaluation of large-scale evaporation retrievals is not a straightforward task. While a number of studies have intercompared a range of these evaporation products by examining the variance amongst them, or by comparison of pixel-scale retrievals against ground-based observations, there is a need to explore more appropriate techniques to comprehensively evaluate remote-sensing-based estimates. One possible approach is to establish the level of product agreement between related hydrological components: for instance, how well do evaporation patterns and response match with precipitation or water storage changes? To assess the suitability of this consistency-based approach for evaluating evaporation products, we focused our investigation on four globally distributed basins in arid and semi-arid environments, comprising the Colorado River basin, Niger River basin, Aral Sea basin, and Lake Eyre basin. In an effort to assess retrieval quality, three satellite-based global evaporation products based on different methodologies and input data, including CSIRO-PML, the MODIS Global Evapotranspiration product (MOD16), and Global Land Evaporation: the Amsterdam Methodology (GLEAM), were evaluated against rainfall data from the Global Precipitation Climatology Project (GPCP) along with Gravity Recovery and Climate Experiment (GRACE) water storage anomalies. To ensure a fair comparison, we evaluated consistency using a degree correlation approach after transforming both evaporation and precipitation data into spherical harmonics. Overall we found no persistent hydrological consistency in these dryland environments. Indeed, the degree correlation showed oscillating values between periods of low and high water storage changes, with a phase difference of about 2-3 months

  17. Simulation of large-scale soil water systems using groundwater data and satellite based soil moisture

    Science.gov (United States)

    Kreye, Phillip; Meon, Günter

    2016-04-01

    Complex concepts for the physically correct depiction of dominant processes in the hydrosphere are increasingly at the forefront of hydrological modelling. Many scientific issues in hydrological modelling demand for additional system variables besides a simulation of runoff only, such as groundwater recharge or soil moisture conditions. Models that include soil water simulations are either very simplified or require a high number of parameters. Against this backdrop there is a heightened demand of observations to be used to calibrate the model. A reasonable integration of groundwater data or remote sensing data in calibration procedures as well as the identifiability of physically plausible sets of parameters is subject to research in the field of hydrology. Since this data is often combined with conceptual models, the given interfaces are not suitable for such demands. Furthermore, the application of automated optimisation procedures is generally associated with conceptual models, whose (fast) computing times allow many iterations of the optimisation in an acceptable time frame. One of the main aims of this study is to reduce the discrepancy between scientific and practical applications in the field of hydrological modelling. Therefore, the soil model DYVESOM (DYnamic VEgetation SOil Model) was developed as one of the primary components of the hydrological modelling system PANTA RHEI. DYVESOMs structure provides the required interfaces for the calibrations made at runoff, satellite based soil moisture and groundwater level. The model considers spatial and temporal differentiated feedback of the development of the vegetation on the soil system. In addition, small scale heterogeneities of soil properties (subgrid-variability) are parameterized by variation of van Genuchten parameters depending on distribution functions. Different sets of parameters are operated simultaneously while interacting with each other. The developed soil model is innovative regarding concept

  18. Electric-Drive Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Septon, Kendall K [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-11

    Electric-drive vehicles use electricity as their primary fuel or to improve the efficiency of conventional vehicle designs. These vehicles can be divided into three categories: Hybrid electric vehicles (HEVs), Plug-in hybrid electric vehicles (PHEVs), All-electric vehicles (EVs). Together, PHEVs and EVs can also be referred to as plug-in electric vehicles (PEVs).

  19. U32: Vehicle Stability and Dynamics: Longer Combination Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Petrolino, Joseph [National Transportation Research Center (NTRC); Spezia, Tony [National Transportation Research Center (NTRC); Arant, Michael [Clemson University; Broshears, Eric [Auburn University, Auburn, Alabama; Chitwood, Caleb [Battelle; Colbert, Jameson [Auburn University, Auburn, Alabama; Hathaway, Richard [Western Michigan University; Keil, Mitch [Western Michigan University; LaClair, Tim J [ORNL; Pape, Doug [Battelle; Patterson, Jim [Hendrickson; Pittro, Collin [Battelle

    2011-01-01

    This study investigated the safety and stability of longer combination vehicles (LCVs), in particular a triple trailer combination behind a commercial tractor, which has more complicated dynamics than the more common tractor in combination with a single semitrailer. The goal was to measure and model the behavior of LCVs in simple maneuvers. Example maneuvers tested and modeled were single and double lane changes, a gradual lane change, and a constant radius curve. In addition to test track data collection and a brief highway test, two computer models of LCVs were developed. One model is based on TruckSim , a lumped parameter model widely used for single semitrailer combinations. The other model was built in Adams software, which more explicitly models the geometry of the components of the vehicle, in terms of compliant structural members. Among other results, the models were able to duplicate the experimentally measured rearward amplification behavior that is characteristic of multi-unit combination vehicles.

  20. Advancing satellite-based solar power forecasting through integration of infrared channels for automatic detection of coastal marine inversion layer

    Energy Technology Data Exchange (ETDEWEB)

    Kostylev, Vladimir; Kostylev, Andrey; Carter, Chris; Mahoney, Chad; Pavlovski, Alexandre; Daye, Tony [Green Power Labs Inc., Dartmouth, NS (Canada); Cormier, Dallas Eugene; Fotland, Lena [San Diego Gas and Electric Co., San Diego, CA (United States)

    2012-07-01

    The marine atmospheric boundary layer is a layer or cool, moist maritime air with the thickness of a few thousand feet immediately below a temperature inversion. In coastal areas as moist air rises from the ocean surface, it becomes trapped and is often compressed into fog above which a layer of stratus clouds often forms. This phenomenon is common for satellite-based solar radiation monitoring and forecasting. Hour ahead satellite-based solar radiation forecasts are commonly using visible spectrum satellite images, from which it is difficult to automatically differentiate low stratus clouds and fog from high altitude clouds. This provides a challenge for cloud motion tyracking and cloud cover forecasting. San Diego Gas and Electric {sup registered} (SDG and E {sup registered}) Marine Layer Project was undertaken to obtain information for integration with PV forecasts, and to develop a detailed understanding of long-term benefits from forecasting Marine Layer (ML) events and their effects on PV production. In order to establish climatological ML patterns, spatial extent and distribution of marine layer, we analyzed visible and IR spectrum satellite images (GOES WEST) archive for the period of eleven years (2000 - 2010). Historical boundaries of marine layers impact were established based on the cross-classification of visible spectrum (VIS) and infrared (IR) images. This approach is successfully used by us and elsewhere for evaluating cloud albedo in common satellite-based techniques for solar radiation monitoring and forecasting. The approach allows differentiation of cloud cover and helps distinguish low laying fog which is the main consequence of marine layer formation. ML occurrence probability and maximum extent inland was established for each hour and day of the analyzed period and seasonal/patterns were described. SDG and E service area is the most affected region by ML events with highest extent and probability of ML occurrence. Influence of ML was the

  1. Use of satellite-based aerosol optical depth and spatial clustering to predict ambient PM2.5 concentrations

    OpenAIRE

    2012-01-01

    Satellite-based PM2.5 monitoring has the potential to complement ground PM2.5 monitoring networks, especially for regions with sparsely distributed monitors. Satellite remote sensing provides data on aerosol optical depth (AOD), which reflects particle abundance in the atmospheric column. Thus AOD has been used in statistical models to predict ground-level PM2.5 concentrations. However, previous studies have shown that AOD may not be a strong predictor of PM2.5 ground levels. Another shortcom...

  2. Tracking Porters

    DEFF Research Database (Denmark)

    Bruun, Maja Hojer; Krause-Jensen, Jakob; Saltofte, Margit

    2015-01-01

    Anthropology attempts to gain insight into people's experiential life-worlds through long-term fieldwork. The quality of anthropological knowledge production, however, does not depend solely on the duration of the stay in the field, but also on a particular way of seeing social situations. The an...... the students followed the work of a group of porters. Drawing on anthropological concepts and research strategies the students gained crucial insights about the potential effects of using tracking technologies in the hospital....

  3. Artificial Potential Field Approach to Path Tracking for a Non-Holonomic Mobile Robot

    DEFF Research Database (Denmark)

    Sørensen, M.J.

    2003-01-01

    This paper introduces a novel path tracking controller for an over-actuated robotic vehicle moving in an agricultural field. The vehicle itself is a four wheel steered, four wheel driven vehicle subject to the two non-holonomic constraints of free rolling and non-slipping wheels. A dynamic model...... of the vehicle is developed and used, together with an artificial potential field method, to synthesize a path tracking controller. The controller drives the vehicle to its destination way-point while avoiding crossing obstacles, e. g. crop rows. One of the key features of the controller is a novel method...... of relating artificial forces with the drive torques of the vehicle....

  4. ROLLING NOISE SIMULATION OF A RAILWAY VEHICLE

    OpenAIRE

    Traian MAZILU

    2013-01-01

    Rolling noise of the railway vehicles is occurred by the wheel/rail vibration excited bythe rolling surfaces roughness. This paper presents an acoustic model able to predict the rollingnoise level of a railway vehicle. The acoustic model is based on a wheel/rail vibration modelwhich takes into account the structural wheel vibration (Remington model) and the bendingvertical waves of the rail. To this, the track model with an infinite Euler Bernoulli beam elasticallysupported on two layers is a...

  5. Satellite-based retrieval of particulate matter concentrations over the United Arab Emirates (UAE)

    Science.gov (United States)

    Zhao, Jun; Temimi, Marouane; Hareb, Fahad; Eibedingil, Iyasu

    2016-04-01

    In this study, an empirical algorithm was established to retrieve particulate matter (PM) concentrations (PM2.5 and PM10) using satellite-derived aerosol optical depth (AOD) over the United Arab Emirates (UAE). Validation of the proposed algorithm using ground truth data demonstrates its good accuracy. Time series of in situ measured PM concentrations between 2014 and 2015 showed high values in summer and low values in winter. Estimated and in situ measured PM concentrations were higher in 2015 than 2014. Remote sensing is an essential tool to reveal and back track the seasonality and inter-annual variations of PM concentrations and provide valuable information on the protection of human health and the response of air quality to anthropogenic activities and climate change.

  6. Launch Vehicle Design Process Characterization Enables Design/Project Tool

    Science.gov (United States)

    Blair, J. C.; Ryan, R. S.; Schutzenhofer, L. A.; Robinson, Nancy (Technical Monitor)

    2001-01-01

    The objectives of the project described in this viewgraph presentation included the following: (1) Provide an overview characterization of the launch vehicle design process; and (2) Delineate design/project tool to identify, document, and track pertinent data.

  7. Sensor Architecture and Task Classification for Agricultural Vehicles and Environments

    Directory of Open Access Journals (Sweden)

    Francisco Rovira-Más

    2010-12-01

    Full Text Available The long time wish of endowing agricultural vehicles with an increasing degree of autonomy is becoming a reality thanks to two crucial facts: the broad diffusion of global positioning satellite systems and the inexorable progress of computers and electronics. Agricultural vehicles are currently the only self-propelled ground machines commonly integrating commercial automatic navigation systems. Farm equipment manufacturers and satellite-based navigation system providers, in a joint effort, have pushed this technology to unprecedented heights; yet there are many unresolved issues and an unlimited potential still to uncover. The complexity inherent to intelligent vehicles is rooted in the selection and coordination of the optimum sensors, the computer reasoning techniques to process the acquired data, and the resulting control strategies for automatic actuators. The advantageous design of the network of onboard sensors is necessary for the future deployment of advanced agricultural vehicles. This article analyzes a variety of typical environments and situations encountered in agricultural fields, and proposes a sensor architecture especially adapted to cope with them. The strategy proposed groups sensors into four specific subsystems: global localization, feedback control and vehicle pose, non-visual monitoring, and local perception. The designed architecture responds to vital vehicle tasks classified within three layers devoted to safety, operative information, and automatic actuation. The success of this architecture, implemented and tested in various agricultural vehicles over the last decade, rests on its capacity to integrate redundancy and incorporate new technologies in a practical way.

  8. Air-sea fluxes and satellite-based estimation of water masses formation

    Science.gov (United States)

    Sabia, Roberto; Klockmann, Marlene; Fernandez-Prieto, Diego; Donlon, Craig

    2015-04-01

    Recent work linking satellite-based measurements of sea surface salinity (SSS) and sea surface temperature (SST) with traditional physical oceanography has demonstrated the capability of generating routinely satellite-derived surface T-S diagrams [1] and analyze the distribution/dynamics of SSS and its relative surface density with respect to in-situ measurements. Even more recently [2,3], this framework has been extended by exploiting these T-S diagrams as a diagnostic tool to derive water masses formation rates and areas. A water mass describes a water body with physical properties distinct from the surrounding water, formed at the ocean surface under specific conditions which determine its temperature and salinity. The SST and SSS (and thus also density) at the ocean surface are largely determined by fluxes of heat and freshwater. The surface density flux is a function of the latter two and describes the change of the density of seawater at the surface. To obtain observations of water mass formation is of great interest, since they serve as indirect observations of the thermo-haline circulation. The SSS data which has become available through the SMOS [4] and Aquarius [5] satellite missions will provide the possibility of studying also the effect of temporally-varying SSS fields on water mass formation. In the present study, the formation of water masses as a function of SST and SSS is derived from the surface density flux by integrating the latter over a specific area and time period in bins of SST and SSS and then taking the derivative of the total density flux with respect to density. This study presents a test case using SMOS SSS, OSTIA SST, as well as Argo ISAS SST and SSS for comparison, heat fluxes from the NOCS Surface Flux Data Set v2.0, OAFlux evaporation and CMORPH precipitation. The study area, initially referred to the North Atlantic, is extended over two additional ocean basins and the study period covers the 2011-2012 timeframe. Yearly, seasonal

  9. Modelling landscape-scale erosion potential related to vehicle disturbances along the U.S.-Mexico border

    Science.gov (United States)

    Villarreal, Miguel; Webb, Robert H.; Norman, Laura M.; Psillas, Jennifer L.; Rosenberg, Abigail S.; Carmichael, Shinji; Petrakis, Roy E.; Sparks, Philip E.

    2014-01-01

    Decades of intensive off-road vehicle use for border security, immigration, smuggling, recreation, and military training along the USA–Mexico border have prompted concerns about long-term human impacts on sensitive desert ecosystems. To help managers identify areas susceptible to soil erosion from anthropogenic activities, we developed a series of erosion potential models based on factors from the Universal Soil Loss Equation (USLE). To better express the vulnerability of soils to human disturbances, we refined two factors whose categorical and spatial representations limit the application of the USLE for non-agricultural landscapes: the C-factor (vegetation cover) and the P-factor (support practice/management). A soil compaction index (P-factor) was calculated as the difference in saturated hydrologic conductivity (Ks) between disturbed and undisturbed soils, which was then scaled up to maps of vehicle disturbances digitized from aerial photography. The C-factor was improved using a satellite-based vegetation index, which was better correlated with estimated ground cover (r2 = 0·77) than data derived from land cover (r2 = 0·06). We identified 9,780 km of unauthorized off-road tracks in the 2,800-km2 study area. Maps of these disturbances, when integrated with soil compaction data using the USLE, provided landscape-scale information on areas vulnerable to erosion from both natural processes and human activities and are detailed enough for adaptive management and restoration planning. The models revealed erosion potential hotspots adjacent to the border and within areas managed as critical habitat for the threatened flat-tailed horned lizard and endangered Sonoran pronghorn.

  10. Sensitivity of a Floodplain Hydrodynamic Model to Satellite-Based DEM Scale and Accuracy: Case Study—The Atchafalaya Basin

    Directory of Open Access Journals (Sweden)

    Hahn Chul Jung

    2015-06-01

    Full Text Available The hydrodynamics of low-lying riverine floodplains and wetlands play a critical role in hydrology and ecosystem processes. Because small topographic features affect floodplain storage and flow velocity, a hydrodynamic model setup of these regions imposes more stringent requirements on the input Digital Elevation Model (DEM compared to upland regions with comparatively high slopes. This current study provides a systematic approach to evaluate the required relative vertical accuracy and spatial resolution of current and future satellite-based altimeters within the context of DEM requirements for 2-D floodplain hydrodynamic models. A case study is presented for the Atchafalaya Basin with a model domain of 1190 km2. The approach analyzes the sensitivity of modeled floodplain water elevation and velocity to typical satellite-based DEM grid-box scale and vertical error, using a previously calibrated version of the physically-based flood inundation model (LISFLOOD-ACC. Results indicate a trade-off relationship between DEM relative vertical error and grid-box size. Higher resolution models are the most sensitive to vertical accuracy, but the impact diminishes at coarser resolutions because of spatial averaging. The results provide guidance to engineers and scientists when defining the observation scales of future altimetry missions such as the   Surface Water and Ocean Topography (SWOT mission from the perspective of numerical modeling requirements for large floodplains of O[103] km2 and greater.

  11. Improving satellite-based PM2.5 estimates in China using Gaussian processes modeling in a Bayesian hierarchical setting.

    Science.gov (United States)

    Yu, Wenxi; Liu, Yang; Ma, Zongwei; Bi, Jun

    2017-08-01

    Using satellite-based aerosol optical depth (AOD) measurements and statistical models to estimate ground-level PM2.5 is a promising way to fill the areas that are not covered by ground PM2.5 monitors. The statistical models used in previous studies are primarily Linear Mixed Effects (LME) and Geographically Weighted Regression (GWR) models. In this study, we developed a new regression model between PM2.5 and AOD using Gaussian processes in a Bayesian hierarchical setting. Gaussian processes model the stochastic nature of the spatial random effects, where the mean surface and the covariance function is specified. The spatial stochastic process is incorporated under the Bayesian hierarchical framework to explain the variation of PM2.5 concentrations together with other factors, such as AOD, spatial and non-spatial random effects. We evaluate the results of our model and compare them with those of other, conventional statistical models (GWR and LME) by within-sample model fitting and out-of-sample validation (cross validation, CV). The results show that our model possesses a CV result (R(2) = 0.81) that reflects higher accuracy than that of GWR and LME (0.74 and 0.48, respectively). Our results indicate that Gaussian process models have the potential to improve the accuracy of satellite-based PM2.5 estimates.

  12. Using satellite-based evapotranspiration estimates to improve the structure of a simple conceptual rainfall-runoff model

    Science.gov (United States)

    Roy, Tirthankar; Gupta, Hoshin V.; Serrat-Capdevila, Aleix; Valdes, Juan B.

    2017-02-01

    Daily, quasi-global (50° N-S and 180° W-E), satellite-based estimates of actual evapotranspiration at 0.25° spatial resolution have recently become available, generated by the Global Land Evaporation Amsterdam Model (GLEAM). We investigate the use of these data to improve the performance of a simple lumped catchment-scale hydrologic model driven by satellite-based precipitation estimates to generate streamflow simulations for a poorly gauged basin in Africa. In one approach, we use GLEAM to constrain the evapotranspiration estimates generated by the model, thereby modifying daily water balance and improving model performance. In an alternative approach, we instead change the structure of the model to improve its ability to simulate actual evapotranspiration (as estimated by GLEAM). Finally, we test whether the GLEAM product is able to further improve the performance of the structurally modified model. Results indicate that while both approaches can provide improved simulations of streamflow, the second approach also improves the simulation of actual evapotranspiration significantly, which substantiates the importance of making diagnostic structural improvements to hydrologic models whenever possible.

  13. Scalable Track Detection in SAR CCD Images

    Energy Technology Data Exchange (ETDEWEB)

    Chow, James G [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Quach, Tu-Thach [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-03-01

    Existing methods to detect vehicle tracks in coherent change detection images, a product of combining two synthetic aperture radar images ta ken at different times of the same scene, rely on simple, fast models to label track pixels. These models, however, are often too simple to capture natural track features such as continuity and parallelism. We present a simple convolutional network architecture consisting of a series of 3-by-3 convolutions to detect tracks. The network is trained end-to-end to learn natural track features entirely from data. The network is computationally efficient and improves the F-score on a standard dataset to 0.988, up fr om 0.907 obtained by the current state-of-the-art method.

  14. INNER TRACKING

    CERN Multimedia

    P. Sharp

    The CMS Inner Tracking Detector continues to make good progress. The Objective for 2006 was to complete all of the CMS Tracker sub-detectors and to start the integration of the sub-detectors into the Tracker Support Tube (TST). The Objective for 2007 is to deliver to CMS a completed, installed, commissioned and calibrated Tracking System (Silicon Strip and Pixels) aligned to < 100µ in April 2008 ready for the first physics collisions at LHC. In November 2006 all of the sub-detectors had been delivered to the Tracker Integration facility (TIF) at CERN and the tests and QA procedures to be carried out on each sub-detector before integration had been established. In December 2006, TIB/TID+ was integrated into TOB+, TIB/TID- was being prepared for integration, and TEC+ was undergoing tests at the final tracker operating temperature (-100 C) in the Lyon cold room. In February 2007, TIB/TID- has been integrated into TOB-, and the installation of the pixel support tube and the services for TI...

  15. Assessing Satellite-Based Fire Data for use in the National Emissions Inventory

    Science.gov (United States)

    Soja, Amber J.; Al-Saadi, Jassim; Giglio, Louis; Randall, Dave; Kittaka, Chieko; Pouliot, George; Kordzi, Joseph J.; Raffuse, Sean; Pace, Thompson G.; Pierce, Thomas E.; Moore, Tom; Biswadev, Roy; Pierce, R. Bradley; Szykman, James J.

    2009-01-01

    Biomass burning is significant to emission estimates because: (1) it can be a major contributor of particulate matter and other pollutants; (2) it is one of the most poorly documented of all sources; (3) it can adversely affect human health; and (4) it has been identified as a significant contributor to climate change through feedbacks with the radiation budget. Additionally, biomass burning can be a significant contributor to a regions inability to achieve the National Ambient Air Quality Standards for PM 2.5 and ozone, particularly on the top 20% worst air quality days. The United States does not have a standard methodology to track fire occurrence or area burned, which are essential components to estimating fire emissions. Satellite imagery is available almost instantaneously and has great potential to enhance emission estimates and their timeliness. This investigation compares satellite-derived fire data to ground-based data to assign statistical error and helps provide confidence in these data. The largest fires are identified by all satellites and their spatial domain is accurately sensed. MODIS provides enhanced spatial and temporal information, and GOES ABBA data are able to capture more small agricultural fires. A methodology is presented that combines these satellite data in Near-Real-Time to produce a product that captures 81 to 92% of the total area burned by wildfire, prescribed, agricultural and rangeland burning. Each satellite possesses distinct temporal and spatial capabilities that permit the detection of unique fires that could be omitted if using data from only one satellite.

  16. Modeling of miner track system during steering motion

    Institute of Scientific and Technical Information of China (English)

    刘少军; 韩庆珏

    2015-01-01

    Equipment for deep sea mining has risen from a position of virtual non-existence to a major industrial significance and in deep sea bed mining, the miner is the key equipment of the whole system that charges with the most complex and dangerous task. Evaluation of trafficability for tracked vehicles for deep sea mining is essential. Rare earth elements (REEs) are used in a wide range of modern applications. These applications are highly specific and substitutes are inferior or unknown. One possible source of the REE could be the poly-metallic nodule, at present explored in the tropical part of the Pacific Ocean. In developing miners of high performance, dynamic behaviour should be investigated under various traveling conditions. The mechanics of tracked vehicles is of continuing interest to organizations and agencies that specify design and operate tracked vehicles. Most works done are on the complete track vehicle system but in this work the research activity is aimed only at the track system with the basic aim of optimizing the track system design so that it can be manufactured by using the minimum resources. Equations and models are developed for the track system of a miner during steering motion. These equations and models could further be used for design optimization of the track system.

  17. Investigation of Torsional Oscillations in Railway Vehicles

    Directory of Open Access Journals (Sweden)

    Fridrichovský Tomáš

    2016-01-01

    Full Text Available The development of semiconductor electro-technics during last decades allowed us to produce railway vehicles with very high tractive power. High performances reveal new problems that were unknown until these days. One of these problems are torsional oscillations of running wheelsets, which may appear and compromise the safety of railway vehicles. This article analyzes dynamical events that may occur in drives of the vehicles and that are bound with transmission of the torque to the wheels during the operation of the vehicle, which is exposed to the variable external influences (adhesion conditions, track irregularities, variation of wheel forces, etc.. This is based on the idea of a model of simplified drive of the real railway vehicle, which is used for simulation purposes. The model serves for the parametric analysis of individual components, to make an effective design or control remedy.

  18. RFID in Space: Exploring the Feasibility and Performance of Gen 2 Tags as a Means of Tracking Equipment, Supplies, and Consumable Products in Cargo Transport Bags onboard a Space Vehicle or Habitat

    Science.gov (United States)

    Jones, Erick C.; Richards, Casey; Herstein, Kelli; Franca, Rodrigo; Yagoda, Evan L.; Vasquez, Reuben

    2008-01-01

    Current inventory management techniques for consumables and supplies aboard space vehicles are burdensome and time consuming. Inventory of food, clothing, and supplies are taken periodically by manually scanning the barcodes on each item. The inaccuracy of reading barcodes and the excessive amount of time it takes for the astronauts to perform this function would be better spent doing scientific experiments. Therefore, there is a need for an alternative method of inventory control by NASA astronauts. Radio Frequency Identification (RFID) is an automatic data capture technology that has potential to create a more effective and user-friendly inventory management system (IMS). In this paper we introduce a Design for Six Sigma Research (DFSS-R) methodology that allows for reliability testing of RFID systems. The research methodology uses a modified sequential design of experiments process to test and evaluate the quality of commercially available RFID technology. The results from the experimentation are compared to the requirements provided by NASA to evaluate the feasibility of using passive Generation 2 RFID technology to improve inventory control aboard crew exploration vehicles.

  19. Robust Vehicle and Traffic Information Extraction for Highway Surveillance

    Directory of Open Access Journals (Sweden)

    C.-C. Jay Kuo

    2005-08-01

    Full Text Available A robust vision-based traffic monitoring system for vehicle and traffic information extraction is developed in this research. It is challenging to maintain detection robustness at all time for a highway surveillance system. There are three major problems in detecting and tracking a vehicle: (1 the moving cast shadow effect, (2 the occlusion effect, and (3 nighttime detection. For moving cast shadow elimination, a 2D joint vehicle-shadow model is employed. For occlusion detection, a multiple-camera system is used to detect occlusion so as to extract the exact location of each vehicle. For vehicle nighttime detection, a rear-view monitoring technique is proposed to maintain tracking and detection accuracy. Furthermore, we propose a method to improve the accuracy of background extraction, which usually serves as the first step in any vehicle detection processing. Experimental results are given to demonstrate that the proposed techniques are effective and efficient for vision-based highway surveillance.

  20. Satellites Based Annual Carbon Dynamics of Africa Tropical Vegetation During the 2003-2014 Period

    Science.gov (United States)

    Baccini, A.

    2015-12-01

    Tracking terrestrial carbon fluxes and predicting how tropical forests will respond to continuous global change requires accurate estimates of annual changes in the density and distribution of carbon stocks at local to global scales. Existing evidence for tropical forests as a carbon sink is based on a limited number of repeated field measurements (Phillips et al. 1998,Lewis et al. 2009, Brienen et al. 2015), while spatially explicit estimates over large areas are limited to emissions derived from deforestation without being able to account for degradation and gain (Harris et al. 2012, Hansen et al. 2013). Here we use 12 years (2003-2014) of satellite data to quantify wall-to-wall annual net changes in aboveground carbon density, showing that Africa tropical forests are a net carbon source on the order of 72.1 ± 32.9 Tg C yr-1. This net release of carbon consists of losses of 205.0 ± 24.7 Tg C yr1 and gains of -132.9 ± 19.3 Tg C yr1. The net gains result from forest growth; net losses result from both reductions in forest area due to deforestation and in biomass density within forests due to degradation; this last accounting overall for 68.9 % of the losses. We anticipate several advantages over the traditional estimates. It measures carbon lost from forest degradation as well as from deforestation. It measures the gains of carbon in forest growth. Data are available to determine annual changes with associated uncertainty. The approach focuses directly on changes in carbon. While global emissions from fossil fuel stabilized in 2014 for the first time in the past 40 years, results from this study indicate that the annual rate of emissions from tropical forests has tended upward over the latest years of the 2003-2014 period.

  1. Resource Tracking Model Updates and Trade Studies

    Science.gov (United States)

    Chambliss, Joe; Stambaugh, Imelda; Moore, Michael

    2016-01-01

    The Resource Tracking Model has been updated to capture system manager and project manager inputs. Both the Trick/General Use Nodal Network Solver Resource Tracking Model (RTM) simulator and the RTM mass balance spreadsheet have been revised to address inputs from system managers and to refine the way mass balance is illustrated. The revisions to the RTM included the addition of a Plasma Pyrolysis Assembly (PPA) to recover hydrogen from Sabatier Reactor methane, which was vented in the prior version of the RTM. The effect of the PPA on the overall balance of resources in an exploration vehicle is illustrated in the increased recycle of vehicle oxygen. Case studies have been run to show the relative effect of performance changes on vehicle resources.

  2. Vibro-acoustic performance of newly designed tram track structures

    Science.gov (United States)

    Haladin, Ivo; Lakušić, Stjepan; Ahac, Maja

    2017-09-01

    Rail vehicles in interaction with a railway structure induce vibrations that are propagating to surrounding structures and cause noise disturbance in the surrounding areas. Since tram tracks in urban areas often share the running surface with road vehicles one of top priorities is to achieve low maintenance and long lasting structure. Research conducted in scope of this paper gives an overview of newly designed tram track structures designated for use on Zagreb tram network and their performance in terms of noise and vibration mitigation. Research has been conducted on a 150 m long test section consisted of three tram track types: standard tram track structure commonly used on tram lines in Zagreb, optimized tram structure for better noise and vibration mitigation and a slab track with double sleepers embedded in a concrete slab, which presents an entirely new approach of tram track construction in Zagreb. Track has been instrumented with acceleration sensors, strain gauges and revision shafts for inspection. Relative deformations give an insight into track structure dynamic load distribution through the exploitation period. Further the paper describes vibro-acoustic measurements conducted at the test site. To evaluate the track performance from the vibro-acoustical standpoint, detailed analysis of track decay rate has been analysed. Opposed to measurement technique using impact hammer for track decay rate measurements, newly developed measuring technique using vehicle pass by vibrations as a source of excitation has been proposed and analysed. Paper gives overview of the method, it’s benefits compared to standard method of track decay rate measurements and method evaluation based on noise measurements of the vehicle pass by.

  3. Track dynamic behavior at rail welds at high speed

    Science.gov (United States)

    Xiao, Guangwen; Xiao, Xinbiao; Guo, Jun; Wen, Zefeng; Jin, Xuesong

    2010-06-01

    As a vehicle passing through a track with different weld irregularities, the dynamic performance of track components is investigated in detail by using a coupled vehicle-track model. In the model, the vehicle is modeled as a multi-body system with 35 degrees of freedom, and a Timoshenko beam is used to model the rails which are discretely supported by sleepers. In the track model, the sleepers are modeled as rigid bodies accounting for their vertical, lateral and rolling motions and assumed to move backward at a constant speed to simulate the vehicle running along the track at the same speed. In the study of the coupled vehicle and track dynamics, the Hertizian contact theory and the theory proposed by Shen-Hedrick-Elkins are, respectively, used to calculate normal and creep forces between the wheel and the rails. In the calculation of the normal forces, the coefficient of the normal contact stiffness is determined by transient contact condition of the wheel and rail surface. In the calculation of the creepages, the lateral, roll-over motions of the rail and the fact that the relative velocity between the wheel and rail in their common normal direction is equal to zero are simultaneously taken into account. The motion equations of the vehicle and track are solved by means of an explicit integration method, in which the rail weld irregularities are modeled as local track vertical deviations described by some ideal cosine functions. The effects of the train speed, the axle load, the wavelength and depth of the irregularities, and the weld center position in a sleeper span on the wheel-rail impact loading are analyzed. The numerical results obtained are greatly useful in the tolerance design of welded rail profile irregularity caused by hand-grinding after rail welding and track maintenances.

  4. Wheel-rail dynamic forces induced by random vertical track irregularities

    Science.gov (United States)

    Spiroiu, M. A.

    2016-08-01

    The present paper investigates the wheel-rail dynamic forces produced by railway vehicles in motion, which are an important issue especially for the high-speed rail transport from the point of view of traffic safety, ride quality and undesirable effects on vehicles, on track and on the land in the vicinity of railways. The research is carried out on a model which includes track system, vehicle unsprung mass, vehicle primary suspension and the bogie sprung mass. The wheel-rail dynamic overloads are evaluated assuming random vertical irregularities of the track. The estimation of wheel-rail dynamic forces is made for a range of vehicle speeds up to 300 km/h and the influence of track and vehicle various parameters is investigated.

  5. Hydrodynamics Research on Amphibious Vehicle Systems:Modeling Theory

    Institute of Scientific and Technical Information of China (English)

    JU Nai-jun

    2006-01-01

    For completing the hydrodynamics software development and the engineering application research on the amphibious vehicle systems, hydrodynamic modeling theory of the amphibious vehicle systems is elaborated, which includes to build up the dynamic system model of amphibious vehicle motion on water, gun tracking-aiming-firing, bullet hit and armored check-target, gunner operating control, and the simulation computed model of time domain for random sea wave.

  6. Small Orbital Stereo Tracking Camera Technology Development

    Science.gov (United States)

    Bryan, Tom; MacLeod, Todd; Gagliano, Larry

    2016-01-01

    On-Orbit Small Debris Tracking and Characterization is a technical gap in the current National Space Situational Awareness necessary to safeguard orbital assets and crew. This poses a major risk of MOD damage to ISS and Exploration vehicles. In 2015 this technology was added to NASA's Office of Chief Technologist roadmap. For missions flying in or assembled in or staging from LEO, the physical threat to vehicle and crew is needed in order to properly design the proper level of MOD impact shielding and proper mission design restrictions. Need to verify debris flux and size population versus ground RADAR tracking. Use of ISS for In-Situ Orbital Debris Tracking development provides attitude, power, data and orbital access without a dedicated spacecraft or restricted operations on-board a host vehicle as a secondary payload. Sensor Applicable to in-situ measuring orbital debris in flux and population in other orbits or on other vehicles. Could enhance safety on and around ISS. Some technologies extensible to monitoring of extraterrestrial debris as well To help accomplish this, new technologies must be developed quickly. The Small Orbital Stereo Tracking Camera is one such up and coming technology. It consists of flying a pair of intensified megapixel telephoto cameras to evaluate Orbital Debris (OD) monitoring in proximity of International Space Station. It will demonstrate on-orbit optical tracking (in situ) of various sized objects versus ground RADAR tracking and small OD models. The cameras are based on Flight Proven Advanced Video Guidance Sensor pixel to spot algorithms (Orbital Express) and military targeting cameras. And by using twin cameras we can provide Stereo images for ranging & mission redundancy. When pointed into the orbital velocity vector (RAM), objects approaching or near the stereo camera set can be differentiated from the stars moving upward in background.

  7. Using NASA's Giovanni Web Portal to Access and Visualize Satellite-based Earth Science Data in the Classroom

    Science.gov (United States)

    Lloyd, Steven; Acker, James G.; Prados, Ana I.; Leptoukh, Gregory G.

    2008-01-01

    One of the biggest obstacles for the average Earth science student today is locating and obtaining satellite-based remote sensing data sets in a format that is accessible and optimal for their data analysis needs. At the Goddard Earth Sciences Data and Information Services Center (GES-DISC) alone, on the order of hundreds of Terabytes of data are available for distribution to scientists, students and the general public. The single biggest and time-consuming hurdle for most students when they begin their study of the various datasets is how to slog through this mountain of data to arrive at a properly sub-setted and manageable data set to answer their science question(s). The GES DISC provides a number of tools for data access and visualization, including the Google-like Mirador search engine and the powerful GES-DISC Interactive Online Visualization ANd aNalysis Infrastructure (Giovanni) web interface.

  8. Experimental free-space distribution of entangled photon pairs over 13 km: towards satellite-based global quantum communication.

    Science.gov (United States)

    Peng, Cheng-Zhi; Yang, Tao; Bao, Xiao-Hui; Zhang, Jun; Jin, Xian-Min; Feng, Fa-Yong; Yang, Bin; Yang, Jian; Yin, Juan; Zhang, Qiang; Li, Nan; Tian, Bao-Li; Pan, Jian-Wei

    2005-04-22

    We report free-space distribution of entangled photon pairs over a noisy ground atmosphere of 13 km. It is shown that the desired entanglement can still survive after both entangled photons have passed through the noisy ground atmosphere with a distance beyond the effective thickness of the aerosphere. This is confirmed by observing a spacelike separated violation of Bell inequality of 2.45+/-0.09. On this basis, we exploit the distributed entangled photon source to demonstrate the Bennett-Brassard 1984 quantum cryptography scheme. The distribution distance of entangled photon pairs achieved in the experiment is for the first time well beyond the effective thickness of the aerosphere, hence presenting a significant step towards satellite-based global quantum communication.

  9. Satellite-based measurements of surface deformation reveal fluid flow associated with the geological storage of carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Vasco, D.W.; Rucci, A.; Ferretti, A.; Novali, F.; Bissell, R.; Ringrose, P.; Mathieson, A.; Wright, I.

    2009-10-15

    Interferometric Synthetic Aperture Radar (InSAR), gathered over the In Salah CO{sub 2} storage project in Algeria, provides an early indication that satellite-based geodetic methods can be effective in monitoring the geological storage of carbon dioxide. An injected volume of 3 million tons of carbon dioxide, from one of the first large-scale carbon sequestration efforts, produces a measurable surface displacement of approximately 5 mm/year. Using geophysical inverse techniques we are able to infer flow within the reservoir layer and within a seismically detected fracture/ fault zone intersecting the reservoir. We find that, if we use the best available elastic Earth model, the fluid flow need only occur in the vicinity of the reservoir layer. However, flow associated with the injection of the carbon dioxide does appear to extend several kilometers laterally within the reservoir, following the fracture/fault zone.

  10. Validation and in vivo assessment of an innovative satellite-based solar UV dosimeter for a mobile app dedicated to skin health.

    Science.gov (United States)

    Morelli, M; Masini, A; Simeone, E; Khazova, M

    2016-09-31

    We present an innovative satellite-based solar UV (ultraviolet) radiation dosimeter with a mobile app interface that has been validated by exploiting both ground-based measurements and an in vivo assessment of the erythemal effects on some volunteers having controlled exposure to solar radiation. The app with this satellite-based UV dosimeter also includes other related functionalities such as the provision of safe sun exposure time updated in real-time and end exposure visual/sound alert. Both validations showed that the system has a good accuracy and reliability needed for health-related applications. This app will be launched on the market by siHealth Ltd in May 2016 under the name of "HappySun" and is available for both Android and iOS devices (more info on ). Extensive R&D activities are on-going for the further improvement of the satellite-based UV dosimeter's accuracy.

  11. 基于物联网的景区观光车跟踪与管理系统设计%System Design for the Scenic Sightseeing Vehicle Tracking and Management Based on the Internet of Things

    Institute of Scientific and Technical Information of China (English)

    关明; 赵志科

    2014-01-01

    针对景区观光车因缺乏自动定位而难以管理的问题,设计一种基于物联网的观光车自动跟踪及管理系统。将射频技术与物联网引入对景区观光车自动跟踪系统的设计,分析该跟踪定位系统的基本组成、过程分析、整体运行。以低成本、低功耗的 RFID 电子标签代替高成本的 GPS 设备,采用三边测量法及 RSSI 算法来实现对观光车的准确定位,并且利用电子化的数据处理模块,来对 RFID 电子标签信息进行读写,从而省去了人工登记景区观光车的借还过程,实现智能化、无人化管理。%This is difficult to manage the scenic sightseeing cars due to lack of automatic positioning sys-tem.This paper is to design a kind of automatic tracking and management based on Internet of things.The radio frequency technology and the Internet of things is introduced to research the automatic tracking sys-tem of the scenic sightseeing cars.And the positioning and tracking system,process analysis,the basic component of the overall operation are analyzed in this paper.In this design,he high cost of GPS devices are replaced the RFID electronic tag with low cost,low power consumption,the trilateral measurement method is adopted and RSSI algorithm tare used to implement the accurate positioning.The design is to read and write the RFID electronic tag information by using of electronic data processing module.This method is easy to realize intelligent and unmanned management,and omits the artificial registration process of scenic sightseeing car.

  12. Effects of the partitioning of diffuse and direct solar radiation on satellite-based modeling of crop gross primary production

    Science.gov (United States)

    Xin, Qinchuan; Gong, Peng; Suyker, Andrew E.; Si, Yali

    2016-08-01

    Modeling crop gross primary production (GPP) is critical to understanding the carbon dynamics of agro-ecosystems. Satellite-based studies have widely used production efficiency models (PEM) to estimate cropland GPP, wherein light use efficiency (LUE) is a key model parameter. One factor that has not been well considered in many PEMs is that canopy LUE could vary with illumination conditions. This study investigates how the partitioning of diffuse and direct solar radiation influences cropland GPP using both flux tower and satellite data. The field-measured hourly LUE under cloudy conditions was 1.50 and 1.70 times higher than that under near clear-sky conditions for irrigated corn and soybean, respectively. We applied a two-leaf model to simulate the canopy radiative transfer process, where modeled photosynthetically active radiation (PAR) absorbed by canopy agreed with tower measurements (R2 = 0.959 and 0.914 for corn and soybean, respectively). Derived canopy LUE became similar after accounting for the impact of light saturation on leaf photosynthetic capacity under varied illumination conditions. The impacts of solar radiation partitioning on satellite-based modeling of crop GPP was examined using vegetation indices (VI) derived from MODIS data. Consistent with the field modeling results, the relationship between daily GPP and PAR × VI under varied illumination conditions showed different patterns in terms of regression slope and intercept. We proposed a function to correct the influences of direct and diffuse radiation partitioning and the explained variance of flux tower GPP increased in all experiments. Our results suggest that the non-linear response of leaf photosynthesis to light absorption contributes to higher canopy LUE on cloudy days than on clear days. We conclude that accounting for the impacts of solar radiation partitioning is necessary for modeling crop GPP on a daily or shorter basis.

  13. Evaluation of three satellite-based latent heat flux algorithms over forest ecosystems using eddy covariance data.

    Science.gov (United States)

    Yao, Yunjun; Zhang, Yuhu; Zhao, Shaohua; Li, Xianglan; Jia, Kun

    2015-06-01

    We have evaluated the performance of three satellite-based latent heat flux (LE) algorithms over forest ecosystems using observed data from 40 flux towers distributed across the world on all continents. These are the revised remote sensing-based Penman-Monteith LE (RRS-PM) algorithm, the modified satellite-based Priestley-Taylor LE (MS-PT) algorithm, and the semi-empirical Penman LE (UMD-SEMI) algorithm. Sensitivity analysis illustrates that both energy and vegetation terms has the highest sensitivity compared with other input variables. The validation results show that three algorithms demonstrate substantial differences in algorithm performance for estimating daily LE variations among five forest ecosystem biomes. Based on the average Nash-Sutcliffe efficiency and root-mean-squared error (RMSE), the MS-PT algorithm has high performance over both deciduous broadleaf forest (DBF) (0.81, 25.4 W/m(2)) and mixed forest (MF) (0.62, 25.3 W/m(2)) sites, the RRS-PM algorithm has high performance over evergreen broadleaf forest (EBF) (0.4, 28.1 W/m(2)) sites, and the UMD-SEMI algorithm has high performance over both deciduous needleleaf forest (DNF) (0.78, 17.1 W/m(2)) and evergreen needleleaf forest (ENF) (0.51, 28.1 W/m(2)) sites. Perhaps the lower uncertainties in the required forcing data for the MS-PT algorithm, the complicated algorithm structure for the RRS-PM algorithm, and the calibrated coefficients of the UMD-SEMI algorithm based on ground-measured data may explain these differences.

  14. Correcting satellite-based precipitation products from SMOS soil moisture data assimilation using two models of different complexity

    Science.gov (United States)

    Román-Cascón, Carlos; Pellarin, Thierry; Gibon, François

    2017-04-01

    Real-time precipitation information at the global scale is quite useful information for many applications. However, satellite-based precipitation products in real time are known to be biased from real values observed in situ. On the other hand, the information about precipitation contained in soil moisture data can be very useful to improve precipitation estimation, since the evolution of this variable is highly influenced by the amount of rainfall at a certain area after a rain event. In this context, the soil moisture data from the Soil Moisture Ocean Salinity (SMOS) satellite is used to correct the precipitation provided by real-time satellite-based products such as CMORPH, TRMM-3B42RT or PERSIANN. In this work, we test an assimilation algorithm based on the data assimilation of SMOS measurements in two models of different complexity: a simple hydrological model (Antecedent Precipitation Index (API)) and a state-of-the-art complex land-surface model (Surface Externalisée (SURFEX)). We show how the assimilation technique, based on a particle filter method, leads to the improvement of correlation and root mean squared error (RMSE) of precipitation estimates, with slightly better results for the simpler (and less expensive computationally) API model. This methodology has been evaluated for six years in ten sites around the world with different features, showing the limitations of the methodology in regions affected by mountainous terrain or by high radio-frequency interferences (RFI), which notably affect the quality of the soil moisture retrievals from brightness temperatures by SMOS. The presented results are promising for a potential near-real time application at the global scale.

  15. Validation and Application of the Modified Satellite-Based Priestley-Taylor Algorithm for Mapping Terrestrial Evapotranspiration

    Directory of Open Access Journals (Sweden)

    Yunjun Yao

    2014-01-01

    Full Text Available Satellite-based vegetation indices (VIs and Apparent Thermal Inertia (ATI derived from temperature change provide valuable information for estimating evapotranspiration (LE and detecting the onset and severity of drought. The modified satellite-based Priestley-Taylor (MS-PT algorithm that we developed earlier, coupling both VI and ATI, is validated based on observed data from 40 flux towers distributed across the world on all continents. The validation results illustrate that the daily LE can be estimated with the Root Mean Square Error (RMSE varying from 10.7 W/m2 to 87.6 W/m2, and with the square of correlation coefficient (R2 from 0.41 to 0.89 (p < 0.01. Compared with the Priestley-Taylor-based LE (PT-JPL algorithm, the MS-PT algorithm improves the LE estimates at most flux tower sites. Importantly, the MS-PT algorithm is also satisfactory in reproducing the inter-annual variability at flux tower sites with at least five years of data. The R2 between measured and predicted annual LE anomalies is 0.42 (p = 0.02. The MS-PT algorithm is then applied to detect the variations of long-term terrestrial LE over Three-North Shelter Forest Region of China and to monitor global land surface drought. The MS-PT algorithm described here demonstrates the ability to map regional terrestrial LE and identify global soil moisture stress, without requiring precipitation information.

  16. 基于OpenGL的卫星跟踪仿真%A Simulation of Tracking a Satellite Based on OpenGL

    Institute of Scientific and Technical Information of China (English)

    黄权; 徐学军

    2007-01-01

    基于开放式三维图形程序标准OpenGL的卫星三维仿真实现,论述了在VC + + 6.0中利用OpenGL进行三维仿真的优点,以及卫星几何模型的构建、卫星运动轨迹的确定、仿真过程的动态显示以及系统软件的主要功能和实现.由此得到了效果比较好的卫星跟踪仿真图.因受限于目前的计算机技术尚不能做到对卫星上所有设备进行图形显示监测,但是卫星三维视觉仿真对于卫星检测系统和卫星管理系统依然具有很大的实用价值.

  17. Use of multiple tracking data in the calibration of short baseline arrays.

    OpenAIRE

    Gembarski, Joseph A.

    1992-01-01

    Approved for public release; distribution is unlimited The calibration problem of a Short Baseline Underwater Vehicle Tracking Range is concerned largely with the coherency of path as the target vehicle passes from the domain of one array into that of another. The arrays are placed approximately in a hexagonal mesh. Thus there are regular locations (triple overlap regions) where the vehicle is tracked simultaneously by three separate arrays. Longbase methods can be use...

  18. Velocity Controller for a Class of Vehicles

    Directory of Open Access Journals (Sweden)

    Herman Przemyslaw

    2017-02-01

    Full Text Available This paper addresses the problem of velocity tracking control for various fully-actuated robotic vehicles. The presented method, which is based on transformation of equations of motion allows one to use, in the control gain matrix, the dynamical couplings existing in the system. Consequently, the dynamics of the vehicle is incorporated into the control process what leads to fast velocity error convergence. The stability of the system under the controller is derived based on Lyapunov argument. Moreover, the robustness of the proposed controller is shown too. The general approach is valid for 6 DOF models as well as other reduced models of vehicles. Simulation results on a 6 DOF indoor airship validate the described velocity tracking methodology.

  19. Artificial Potential Field Approach to Path Tracking for a Non-Holonomic Mobile Robot

    DEFF Research Database (Denmark)

    Sørensen, M.J.

    2003-01-01

    This paper introduces a novel path tracking controller for an over-actuated robotic vehicle moving in an agricultural field. The vehicle itself is a four wheel steered, four wheel driven vehicle subject to the two non-holonomic constraints of free rolling and non-slipping wheels. A dynamic model...... of the vehicle is developed and used, together with an artificial potential field method, to synthesize a path tracking controller. The controller drives the vehicle to its destination way-point while avoiding crossing obstacles, e. g. crop rows. One of the key features of the controller is a novel method...

  20. Tracking Clean Energy Progress 2013

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-06-01

    Tracking Clean Energy Progress 2013 (TCEP 2013) examines progress in the development and deployment of key clean energy technologies. Each technology and sector is tracked against interim 2020 targets in the IEA Energy Technology Perspectives 2012 2°C scenario, which lays out pathways to a sustainable energy system in 2050. Stark message emerge: progress has not been fast enough; large market failures are preventing clean energy solutions from being taken up; considerable energy efficiency remains untapped; policies need to better address the energy system as a whole; and energy-related research, development and demonstration need to accelerate. Alongside these grim conclusions there is positive news. In 2012, hybrid-electric vehicle sales passed the 1 million mark. Solar photovoltaic systems were being installed at a record pace. The costs of most clean energy technologies fell more rapidly than anticipated.

  1. "Bait vehicle" technologies and motor vehicle theft along the southwest border.

    Energy Technology Data Exchange (ETDEWEB)

    Aldridge, Chris D.

    2007-09-01

    In 2005, over 33% of all the vehicles reported stolen in the United States occurred in the four southwestern border states of California, Arizona, New Mexico, and Texas, which all have very high vehicle theft rates in comparison to the national average. This report describes the utilization of 'bait vehicles' and associated technologies in the context of motor vehicle theft along the southwest border of the U.S. More than 100 bait vehicles are estimated to be in use by individual agencies and auto theft task forces in the southwestern border states. The communications, tracking, mapping, and remote control technologies associated with bait vehicles provide law enforcement with an effective tool to obtain arrests in vehicle theft 'hot spots'. Recorded audio and video from inside the vehicle expedite judicial proceedings as offenders rarely contest the evidence presented. At the same time, law enforcement is very interested in upgrading bait vehicle technology through the use of live streaming video for enhanced officer safety and improved situational awareness. Bait vehicle effectiveness could be enhanced by dynamic analysis of motor theft trends through exploitation of geospatial, timeline, and other analytical tools to better inform very near-term operational decisions, including the selection of particular vehicle types. This 'information-led' capability would especially benefit from more precise and timely information on the location of vehicles stolen in the United States and found in Mexico. Introducing Automated License Plate Reading (ALPR) technology to collect information associated with stolen motor vehicles driven into Mexico could enhance bait vehicle effectiveness.

  2. Towards a protocol for validating satellite-based Land Surface Temperature: Application to AATSR data

    Science.gov (United States)

    Ghent, Darren; Schneider, Philipp; Remedios, John

    2013-04-01

    Land surface temperature (LST) retrieval accuracy can be challenging as a result of emissivity variability and atmospheric effects. Surface emissivities can be highly variable owing to the heterogeneity of the land; a problem which is amplified in regions of high topographic variance or for larger viewing angles. Atmospheric effects caused by the presence of aerosols and by water vapour absorption can give a bias to the underlying LST. Combined, atmospheric effects and emissivity variability can result in retrieval errors of several degrees. If though these are appropriately handled satellite-derived LST products can be used to improve our ability to monitor and to understand land surface and climate change processes, such as desertification, urbanization, deforestation and land/atmosphere coupling. Here we present validation of an improved LST data record from the Advanced Along-Track Scanning Radiometer (AATSR) and illustrate the improvements in accuracy and precision compared with the standard ESA LST product. Validation is a critical part of developing any satellite product, although over the land heterogeneity ensures this is a challenging undertaking. A substantial amount of previous effort has gone into the area of structuring and standardizing calibration and validation approaches within the field of Earth Observation. However, no unified approach for accomplishing this for LST has yet to be practised by the LST community. Recent work has attempted to address this situation with the development of a protocol for validating LST (Schneider et al., 2012) under the auspices of ESA and the support of the wider LST community. We report here on a first application of this protocol to satellite LST data. The approach can briefly be summarised thus: in situ validation is performed where ground-based observations are available - being predominantly homogeneous sites; heterogeneous pixels are validated by way of established radiometric-based techniques (Wan and Li

  3. INNER TRACKING

    CERN Multimedia

    P. Sharp

    The CMS Inner Tracking Detector continues to make good progress. The successful commissioning of ~ 25% of the Silicon Strip Tracker was completed in the Tracker Integration Facility (TIF) at CERN in July 2007 and the Tracker has since been prepared for moving and installation into CMS at P5. The Tracker was ready to move on schedule in September 2007. The Installation of the Tracker cooling pipes and LV cables between Patch Panel 1 (PP1) on the inside the CMS magnet cryostat, and the cooling plants and power system racks on the balconies has been completed. The optical fibres from PP1 to the readout FEDs in the USC have been installed, together with the Tracker cable channels, in parallel with the installation of the EB/HB services. All of the Tracker Safety, Power, DCS and the VME Readout Systems have been installed at P5 and are being tested and commissioned with CMS. It is planned to install the Tracker into CMS before Christmas. The Tracker will then be connected to the pre-installed services on Y...

  4. INNER TRACKING

    CERN Multimedia

    P. Sharp

    The CMS Inner Tracking Detector continues to make good progress. The successful commissioning of ~ 25% of the Silicon Strip Tracker was completed in the Tracker Integration Facility (TIF) at CERN on 18 July 2007 and the Tracker has since been prepared for moving and installation into CMS at P5. The Tracker will be ready to move on schedule in September 2007. The Installation of the Tracker cooling pipes and LV cables between Patch Panel 1 (PP1) on the inside the CMS magnet cryostat, and the cooling plants and power system racks on the balconies has been completed. The optical fibres from PP1 to the readout FEDs in the USC will be installed in parallel with the installation of the EB/HB services, and will be completed in October. It is planned to install the Tracker into CMS at the end of October, after the completion of the installation of the EB/HB services. The Tracker will then be connected to the pre-installed services on YB0 and commissioned with CMS in December. The FPix and BPix continue to make ...

  5. Patient Treatment Tracking Chart

    Science.gov (United States)

    ... ZIP code here Hepatitis C Treatment Tracking Chart Patient Treatment Tracking Chart Patient Treatment Tracking Chart Sample Chart This chart is ... this website Submit Share this page Related Resource Patient Treatment Tutorial return to top CONNECT Veterans Crisis ...

  6. A Night Time Application for a Real-Time Vehicle Detection Algorithm Based on Computer Vision

    Directory of Open Access Journals (Sweden)

    Shifu Zhou

    2013-03-01

    Full Text Available Vehicle detection technology is the key technology of intelligent transportation systems, attracting the attention of many researchers. Although much literature has been published concerning daytime vehicle detection, little has been published concerning nighttime vehicle detection. In this study, a nighttime vehicle detection algorithm, consisting of headlight segmentation, headlight pairing and headlight tracking, is proposed. First, the pixels of the headlights are segmented in nighttime traffic images, through the use of the thresholding method. Then the pixels of the headlights are grouped and labeled, to analyze the characteristics of related components, such as area, location and size. Headlights are paired based on their location and size and then tracked via a tracking procedure designed to detect vehicles. Vehicles with only one headlight or those with three or four headlights are also detected. Experimental results show that the proposed algorithm is robust and effective in detecting vehicles in nighttime traffic.

  7. Space Ops 2002: Bringing Space Operations into the 21st Century. Track 3: Operations, Mission Planning and Control. 2nd Generation Reusable Launch Vehicle-Concepts for Flight Operations

    Science.gov (United States)

    Hagopian, Jeff

    2002-01-01

    With the successful implementation of the International Space Station (ISS), the National Aeronautics and Space Administration (NASA) enters a new era of opportunity for scientific research. The ISS provides a working laboratory in space, with tremendous capabilities for scientific research. Utilization of these capabilities requires a launch system capable of routinely transporting crew and logistics to/from the ISS, as well as supporting ISS assembly and maintenance tasks. The Space Shuttle serves as NASA's launch system for performing these functions. The Space Shuttle also serves as NASA's launch system for supporting other science and servicing missions that require a human presence in space. The Space Shuttle provides proof that reusable launch vehicles are technically and physically implementable. However, a couple of problems faced by NASA are the prohibitive cost of operating and maintaining the Space Shuttle and its relative inability to support high launch rates. The 2nd Generation Reusable Launch Vehicle (2nd Gen RLV) is NASA's solution to this problem. The 2nd Gen RLV will provide a robust launch system with increased safety, improved reliability and performance, and less cost. The improved performance and reduced costs of the 2nd Gen RLV will free up resources currently spent on launch services. These resource savings can then be applied to scientific research, which in turn can be supported by the higher launch rate capability of the 2nd Gen RLV. The result is a win - win situation for science and NASA. While meeting NASA's needs, the 2nd Gen RLV also provides the United States aerospace industry with a commercially viable launch capability. One of the keys to achieving the goals of the 2nd Gen RLV is to develop and implement new technologies and processes in the area of flight operations. NASA's experience in operating the Space Shuttle and the ISS has brought to light several areas where automation can be used to augment or eliminate functions

  8. The sophisticated control of the tram bogie on track

    Directory of Open Access Journals (Sweden)

    Radovan DOLECEK

    2015-09-01

    Full Text Available The paper deals with the problems of routing control algorithms of new conception of tram vehicle bogie. The main goal of these research activities is wear reduction of rail wheels and tracks, wear reduction of traction energy losses and increasing of running comfort. The testing experimental tram vehicle with special bogie construction powered by traction battery is utilized for these purposes. This vehicle has a rotary bogie with independent rotating wheels driven by permanent magnets synchronous motors and a solid axle. The wheel forces in bogie are measured by large amounts of the various sensors placed on the testing experimental tram vehicle. Nowadays the designed control algorithms are implemented to the vehicle superset control system. The traction requirements and track characteristics have an effect to these control algorithms. This control including sophisticated routing brings other improvements which is verified and corrected according to individual traction and driving characteristics, and opens new possibilities.

  9. Persistent Aerial Tracking system for UAVs

    KAUST Repository

    Mueller, Matthias

    2016-12-19

    In this paper, we propose a persistent, robust and autonomous object tracking system for unmanned aerial vehicles (UAVs) called Persistent Aerial Tracking (PAT). A computer vision and control strategy is applied to a diverse set of moving objects (e.g. humans, animals, cars, boats, etc.) integrating multiple UAVs with a stabilized RGB camera. A novel strategy is employed to successfully track objects over a long period, by ‘handing over the camera’ from one UAV to another. We evaluate several state-of-the-art trackers on the VIVID aerial video dataset and additional sequences that are specifically tailored to low altitude UAV target tracking. Based on the evaluation, we select the leading tracker and improve upon it by optimizing for both speed and performance, integrate the complete system into an off-the-shelf UAV, and obtain promising results showing the robustness of our solution in real-world aerial scenarios.

  10. 多无人机协同目标跟踪闭环最优控制方法%A Closed-loop Optimal Control for Multiple Unmanned Aerial Vehicles Cooperative Target Tracking

    Institute of Scientific and Technical Information of China (English)

    钟春梅; 赵振宇; 孙海波; 周锐

    2012-01-01

    Considering the problems of poor real-time property or optimization for the existing methods, a closed-loop optimal control method for cooperative target tracking based on the optimal condition was proposed for the control of approaching and loitering stages. The adaptive azimuth control of UAVs was implemented according to the relative distance and angle between the UAV and target in order to gain the optimal observing geometry as quickly as possible. The simulation results demonstrated that the optimal observing geometry during approaching and loitering stages was achieved with high real-time and optimization.%针对目前多机协同目标跟踪方法缺乏实时性和最优性等问题.提出了一种由趋近和盘旋两阶段组成的多无人机协同目标跟踪闭环最优控制方法.当距离目标远时自适应调节无人机方位角优先且尽快趋近目标;而当距离近时则自适应调节无人机方位角优先且尽快实现最优观测视线夹角.仿真结果证明了:在靠近和盘旋阶段均确保了最优性观测条件,且具有较好的实时性和最优性.

  11. Broadband vehicle-to-vehicle communication using an extended autonomous cruise control sensor

    Science.gov (United States)

    Heddebaut, M.; Rioult, J.; Ghys, J. P.; Gransart, Ch; Ambellouis, S.

    2005-06-01

    For several years road vehicle autonomous cruise control (ACC) systems as well as anti-collision radar have been developed. Several manufacturers currently sell this equipment. The current generation of ACC sensors only track the first preceding vehicle to deduce its speed and position. These data are then used to compute, manage and optimize a safety distance between vehicles, thus providing some assistance to car drivers. However, in real conditions, to elaborate and update a real time driving solution, car drivers use information about speed and position of preceding and following vehicles. This information is essentially perceived using the driver's eyes, binocular stereoscopic vision performed through the windscreens and rear-view mirrors. Furthermore, within a line of vehicles, the frontal road perception of the first vehicle is very particular and highly significant. Currently, all these available data remain strictly on-board the vehicle that has captured the perception information and performed these measurements. To get the maximum effectiveness of all these approaches, we propose that this information be shared in real time with the following vehicles, within the convoy. On the basis of these considerations, this paper technically explores a cost-effective solution to extend the basic ACC sensor function in order to simultaneously provide a vehicle-to-vehicle radio link. This millimetre wave radio link transmits relevant broadband perception data (video, localization...) to following vehicles, along the line of vehicles. The propagation path between the vehicles uses essentially grazing angles of incidence of signals over the road surface including millimetre wave paths beneath the cars.

  12. Vehicle Development Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports the development of prototype deployment platform vehicles for offboard countermeasure systems.DESCRIPTION: The Vehicle Development Laboratory is...

  13. Vehicle Development Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Supports the development of prototype deployment platform vehicles for offboard countermeasure systems. DESCRIPTION: The Vehicle Development Laboratory is...

  14. Relation between Ocean SST Dipoles and Downwind Continental Croplands Assessed for Early Management Using Satellite-based Photosynthesis Models

    Science.gov (United States)

    Kaneko, Daijiro

    2015-04-01

    Crop-monitoring systems with the unit of carbon-dioxide sequestration for environmental issues related to climate adaptation to global warming have been improved using satellite-based photosynthesis and meteorological conditions. Early management of crop status is desirable for grain production, stockbreeding, and bio-energy providing that the seasonal climate forecasting is sufficiently accurate. Incorrect seasonal forecasting of crop production can damage global social activities if the recognized conditions are unsatisfied. One cause of poor forecasting related to the atmospheric dynamics at the Earth surface, which reflect the energy budget through land surface, especially the oceans and atmosphere. Recognition of the relation between SST anomalies (e.g. ENSO, Atlantic Niño, Indian dipoles, and Ningaloo Niño) and crop production, as expressed precisely by photosynthesis or the sequestrated-carbon rate, is necessary to elucidate the mechanisms related to poor production. Solar radiation, surface air temperature, and water stress all directly affect grain vegetation photosynthesis. All affect stomata opening, which is related to the water balance or definition by the ratio of the Penman potential evaporation and actual transpiration. Regarding stomata, present data and reanalysis data give overestimated values of stomata opening because they are extended from wet models in forests rather than semi-arid regions commonly associated with wheat, maize, and soybean. This study applies a complementary model based on energy conservation for semi-arid zones instead of the conventional Penman-Monteith method. Partitioning of the integrated Net PSN enables precise estimation of crop yields by modifying the semi-closed stomata opening. Partitioning predicts production more accurately using the cropland distribution already classified using satellite data. Seasonal crop forecasting should include near-real-time monitoring using satellite-based process crop models to avoid

  15. Using NASA's Giovanni Web Portal to Access and Visualize Satellite-Based Earth Science Data in the Classroom

    Science.gov (United States)

    Lloyd, S. A.; Acker, J. G.; Prados, A. I.; Leptoukh, G. G.

    2008-12-01

    One of the biggest obstacles for the average Earth science student today is locating and obtaining satellite- based remote sensing datasets in a format that is accessible and optimal for their data analysis needs. At the Goddard Earth Sciences Data and Information Services Center (GES-DISC) alone, on the order of hundreds of Terabytes of data are available for distribution to scientists, students and the general public. The single biggest and time-consuming hurdle for most students when they begin their study of the various datasets is how to slog through this mountain of data to arrive at a properly sub-setted and manageable dataset to answer their science question(s). The GES DISC provides a number of tools for data access and visualization, including the Google-like Mirador search engine and the powerful GES-DISC Interactive Online Visualization ANd aNalysis Infrastructure (Giovanni) web interface. Giovanni provides a simple way to visualize, analyze and access vast amounts of satellite-based Earth science data. Giovanni's features and practical examples of its use will be demonstrated, with an emphasis on how satellite remote sensing can help students understand recent events in the atmosphere and biosphere. Giovanni is actually a series of sixteen similar web-based data interfaces, each of which covers a single satellite dataset (such as TRMM, TOMS, OMI, AIRS, MLS, HALOE, etc.) or a group of related datasets (such as MODIS and MISR for aerosols, SeaWIFS and MODIS for ocean color, and the suite of A-Train observations co-located along the CloudSat orbital path). Recently, ground-based datasets have been included in Giovanni, including the Northern Eurasian Earth Science Partnership Initiative (NEESPI), and EPA fine particulate matter (PM2.5) for air quality. Model data such as the Goddard GOCART model and MERRA meteorological reanalyses (in process) are being increasingly incorporated into Giovanni to facilitate model- data intercomparison. A full suite of data

  16. Carbon export fluxes in the Southern Ocean: results from inverse modeling and comparison with satellite-based estimates

    Science.gov (United States)

    Schlitzer, Reiner

    The use of dissolved nutrients and carbon for photosynthesis in the euphotic zone and the subsequent downward transport of particulate and dissolved organic material strongly affect carbon concentrations in surface water and thus the air-sea exchange of CO 2. Efforts to quantify the downward carbon flux for the whole ocean or on basin-scales are hampered by the sparseness of direct productivity or flux measurements. Here, a global ocean circulation, biogeochemical model is used to determine rates of export production and vertical carbon fluxes in the Southern Ocean. The model exploits the existing large sets of hydrographic, oxygen, nutrient and carbon data that contain information on the underlying biogeochemical processes. The model is fitted to the data by systematically varying circulation, air-sea fluxes, production, and remineralization rates simultaneously. Use of the adjoint method yields model property simulations that are in very good agreement with measurements. In the model, the total integrated export flux of particulate organic matter necessary for the realistic reproduction of nutrient data is significantly larger than export estimates derived from primary productivity maps. Of the 10,000 TgC yr -1(10 GtC yr -1) required globally, the Southern Ocean south of 30°S contributes about 3000 TgC yr -1 (33%), most of it occurring in a zonal belt along the Antarctic Circumpolar Current and in the Peru, Chile and Namibia coastal upwelling regions. The export flux of POC for the area south of 50°S amounts to 1000±210 TgC yr -1, and the particle flux in 1000 m for the same area is 115±20 TgC yr -1. Unlike for the global ocean, the contribution of the downward flux of dissolved organic carbon is significant in the Southern Ocean in the top 500 m of the water column. Comparison with satellite-based productivity estimates (CZCS and SeaWiFS) shows a relatively good agreement over most of the ocean except for the Southern Ocean south of 50°S, where the model

  17. Path Tracking Control of Automatic Parking Cloud Model considering the Influence of Time Delay

    Directory of Open Access Journals (Sweden)

    Yiding Hua

    2017-01-01

    Full Text Available This paper establishes the kinematic model of the automatic parking system and analyzes the kinematic constraints of the vehicle. Furthermore, it solves the problem where the traditional automatic parking system model fails to take into account the time delay. Firstly, based on simulating calculation, the influence of time delay on the dynamic trajectory of a vehicle in the automatic parking system is analyzed under the transverse distance Dlateral between different target spaces. Secondly, on the basis of cloud model, this paper utilizes the tracking control of an intelligent path closer to human intelligent behavior to further study the Cloud Generator-based parking path tracking control method and construct a vehicle path tracking control model. Moreover, tracking and steering control effects of the model are verified through simulation analysis. Finally, the effectiveness and timeliness of automatic parking controller in the aspect of path tracking are tested through a real vehicle experiment.

  18. Solar tracking system

    Energy Technology Data Exchange (ETDEWEB)

    Okandan, Murat; Nielson, Gregory N.

    2016-07-12

    Solar tracking systems, as well as methods of using such solar tracking systems, are disclosed. More particularly, embodiments of the solar tracking systems include lateral supports horizontally positioned between uprights to support photovoltaic modules. The lateral supports may be raised and lowered along the uprights or translated to cause the photovoltaic modules to track the moving sun.

  19. DynaMax+ ground-tracking algorithm

    Science.gov (United States)

    Smock, Brandon; Gader, Paul; Wilson, Joseph

    2011-06-01

    In this paper, we propose a new method for performing ground-tracking using ground-penetrating radar (GPR). Ground-tracking involves identifying the air-ground interface, which is usually the dominant feature in a radar image but frequently is obscured or mimicked by other nearby elements. It is an important problem in landmine detection using vehicle-mounted systems because antenna motion, caused by bumpy ground, can introduce distortions in downtrack radar images, which ground-tracking makes it possible to correct. Because landmine detection is performed in real-time, any algorithm for ground-tracking must be able to run quickly, prior to other, more computationally expensive algorithms for detection. In this investigation, we first describe an efficient algorithm, based on dynamic programming, that can be used in real-time for tracking the ground. We then demonstrate its accuracy through a quantitative comparison with other proposed ground-tracking methods, and a qualitative comparison showing that its ground-tracking is consistent with human observations in challenging terrain.

  20. Improving snow process modeling with satellite-based estimation of near-surface-air-temperature lapse rate

    Science.gov (United States)

    Wang, Lei; Sun, Litao; Shrestha, Maheswor; Li, Xiuping; Liu, Wenbin; Zhou, Jing; Yang, Kun; Lu, Hui; Chen, Deliang

    2016-10-01

    In distributed hydrological modeling, surface air temperature (Tair) is of great importance in simulating cold region processes, while the near-surface-air-temperature lapse rate (NLR) is crucial to prepare Tair (when interpolating Tair from site observations to model grids). In this study, a distributed biosphere hydrological model with improved snow physics (WEB-DHM-S) was rigorously evaluated in a typical cold, large river basin (e.g., the upper Yellow River basin), given a mean monthly NLRs. Based on the validated model, we have examined the influence of the NLR on the simulated snow processes and streamflows. We found that the NLR has a large effect on the simulated streamflows, with a maximum difference of greater than 24% among the various scenarios for NLRs considered. To supplement the insufficient number of monitoring sites for near-surface-air-temperature at developing/undeveloped mountain regions, the nighttime Moderate Resolution Imaging Spectroradiometer land surface temperature is used as an alternative to derive the approximate NLR at a finer spatial scale (e.g., at different elevation bands, different land covers, different aspects, and different snow conditions). Using satellite-based estimation of NLR, the modeling of snow processes has been greatly refined. Results show that both the determination of rainfall/snowfall and the snowpack process were significantly improved, contributing to a reduced summer evapotranspiration and thus an improved streamflow simulation.