The Lateral Tracking Control for the Intelligent Vehicle Based on Adaptive PID Neural Network

Directory of Open Access Journals (Sweden)

Gaining Han

2017-05-01

Full Text Available The intelligent vehicle is a complicated nonlinear system, and the design of a path tracking controller is one of the key technologies in intelligent vehicle research. This paper mainly designs a lateral control dynamic model of the intelligent vehicle, which is used for lateral tracking control. Firstly, the vehicle dynamics model (i.e., transfer function is established according to the vehicle parameters. Secondly, according to the vehicle steering control system and the CARMA (Controlled Auto-Regression and Moving-Average model, a second-order control system model is built. Using forgetting factor recursive least square estimation (FFRLS, the system parameters are identified. Finally, a neural network PID (Proportion Integral Derivative controller is established for lateral path tracking control based on the vehicle model and the steering system model. Experimental simulation results show that the proposed model and algorithm have the high real-time and robustness in path tracing control. This provides a certain theoretical basis for intelligent vehicle autonomous navigation tracking control, and lays the foundation for the vertical and lateral coupling control.

Visual Vehicle Tracking Based on Deep Representation and Semisupervised Learning

Directory of Open Access Journals (Sweden)

Yingfeng Cai

2017-01-01

Full Text Available Discriminative tracking methods use binary classification to discriminate between the foreground and background and have achieved some useful results. However, the use of labeled training samples is insufficient for them to achieve accurate tracking. Hence, discriminative classifiers must use their own classification results to update themselves, which may lead to feedback-induced tracking drift. To overcome these problems, we propose a semisupervised tracking algorithm that uses deep representation and transfer learning. Firstly, a 2D multilayer deep belief network is trained with a large amount of unlabeled samples. The nonlinear mapping point at the top of this network is subtracted as the feature dictionary. Then, this feature dictionary is utilized to transfer train and update a deep tracker. The positive samples for training are the tracked vehicles, and the negative samples are the background images. Finally, a particle filter is used to estimate vehicle position. We demonstrate experimentally that our proposed vehicle tracking algorithm can effectively restrain drift while also maintaining the adaption of vehicle appearance. Compared with similar algorithms, our method achieves a better tracking success rate and fewer average central-pixel errors.

Analysis of orbit determination from Earth-based tracking for relay satellites in a perturbed areostationary orbit

Science.gov (United States)

Romero, P.; Pablos, B.; Barderas, G.

2017-07-01

Areostationary satellites are considered a high interest group of satellites to satisfy the telecommunications needs of the foreseen missions to Mars. An areostationary satellite, in an areoequatorial circular orbit with a period of 1 Martian sidereal day, would orbit Mars remaining at a fixed location over the Martian surface, analogous to a geostationary satellite around the Earth. This work addresses an analysis of the perturbed orbital motion of an areostationary satellite as well as a preliminary analysis of the aerostationary orbit estimation accuracy based on Earth tracking observations. First, the models for the perturbations due to the Mars gravitational field, the gravitational attraction of the Sun and the Martian moons, Phobos and Deimos, and solar radiation pressure are described. Then, the observability from Earth including possible occultations by Mars of an areostationary satellite in a perturbed areosynchronous motion is analyzed. The results show that continuous Earth-based tracking is achievable using observations from the three NASA Deep Space Network Complexes in Madrid, Goldstone and Canberra in an occultation-free scenario. Finally, an analysis of the orbit determination accuracy is addressed considering several scenarios including discontinuous tracking schedules for different epochs and different areoestationary satellites. Simulations also allow to quantify the aerostationary orbit estimation accuracy for various tracking series durations and observed orbit arc-lengths.

Multi-Perspective Vehicle Detection and Tracking

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......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....

Correlation of track irregularities and vehicle responses based on measured data

Science.gov (United States)

Karis, Tomas; Berg, Mats; Stichel, Sebastian; Li, Martin; Thomas, Dirk; Dirks, Babette

2018-06-01

Track geometry quality and dynamic vehicle response are closely related, but do not always correspond with each other in terms of maximum values and standard deviations. This can often be seen to give poor results in analyses with correlation coefficients or regression analysis. Measured data from both the EU project DynoTRAIN and the Swedish Green Train (Gröna Tåget) research programme is used in this paper to evaluate track-vehicle response for three vehicles. A single degree of freedom model is used as an inspiration to divide track-vehicle interaction into three parts, which are analysed in terms of correlation. One part, the vertical axle box acceleration divided by vehicle speed squared (?) and the second spatial derivative of the vertical track irregularities (?), is shown to be the weak link with lower correlation coefficients than the other parts. Future efforts should therefore be directed towards investigating the relation between axle box accelerations and track irregularity second derivatives.

Satellite Images-Based Obstacle Recognition and Trajectory Generation for Agricultural Vehicles

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Mehmet Bodur

2015-12-01

Full Text Available In this study, a method for the generation of tracking trajectory points, detection and positioning of obstacles in agricultural fields have been presented. Our principal contribution is to produce traceable GPS trajectories for agricultural vehicles to be utilized by path planning algorithms, rather than a new path planning algorithm. The proposed system works with minimal initialization requirements, specifically, a single geographical coordinate entry of an agricultural field. The automation of agricultural plantation requires many aspects to be addressed, many of which have been covered in previous studies. Depending on the type of crop, different agricultural vehicles may be used in the field. However, regardless of their application, they all follow a specified trajectory in the field. This study takes advantage of satellite images for the detection and positioning of obstacles, and the generation of GPS trajectories in the agricultural realm. A set of image processing techniques is applied in Matlab for detection and positioning.

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

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Guo, Junbin; Wang, Jianqiang; Guo, Xiaosong; Yu, Chuanqiang; Sun, Xiaoyan

2014-01-01

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. PMID:25195855

Consensus seeking, formation keeping, and trajectory tracking in multiple vehicle cooperative control

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Ren, Wei

Cooperative control problems for multiple vehicle systems can be categorized as either formation control problems with applications to mobile robots, unmanned air vehicles, autonomous underwater vehicles, satellites, aircraft, spacecraft, and automated highway systems, or non-formation control problems such as task assignment, cooperative transport, cooperative role assignment, air traffic control, cooperative timing, and cooperative search. The cooperative control of multiple vehicle systems poses significant theoretical and practical challenges. For cooperative control strategies to be successful, numerous issues must be addressed. We consider three important and correlated issues: consensus seeking, formation keeping, and trajectory tracking. For consensus seeking, we investigate algorithms and protocols so that a team of vehicles can reach consensus on the values of the coordination data in the presence of imperfect sensors, communication dropout, sparse communication topologies, and noisy and unreliable communication links. The main contribution of this dissertation in this area is that we show necessary and/or sufficient conditions for consensus seeking with limited, unidirectional, and unreliable information exchange under fixed and switching interaction topologies (through either communication or sensing). For formation keeping, we apply a so-called "virtual structure" approach to spacecraft formation flying and multi-vehicle formation maneuvers. As a result, single vehicle path planning and trajectory generation techniques can be employed for the virtual structure while trajectory tracking strategies can be employed for each vehicle. The main contribution of this dissertation in this area is that we propose a decentralized architecture for multiple spacecraft formation flying in deep space with formation feedback introduced. This architecture ensures the necessary precision in the presence of actuator saturation, internal and external disturbances, and

Tracked vehicles in hazardous environments

International Nuclear Information System (INIS)

Jones, S.; Walton, P.J.

1993-01-01

A programme of remote inspections has been conducted on the Magnox steel reactor pressure vessel at Trawsfynydd Power Station using climbing vehicles. Tracked remotely operated vehicles supported the inspection programme by assisting with the delivery and recovery of the climbing vehicles and facilitating the use of various accessory packages. This paper presents details of the support project, the tracked vehicles and of the uses made of them during the inspection programme. (author)

Vehicle track interaction safety standards

Science.gov (United States)

2014-04-02

Vehicle/Track Interaction (VTI) Safety Standards aim to : reduce the risk of derailments and other accidents attributable : to the dynamic interaction between moving vehicles and the : track over which they operate. On March 13, 2013, the Federal : R...

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.

Disturbance observer-based L1 robust tracking control for hypersonic vehicles with T-S disturbance modeling

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Yang Yi

2016-11-01

Full Text Available This article concerns a disturbance observer-based L1 robust anti-disturbance tracking algorithm for the longitudinal models of hypersonic flight vehicles with different kinds of unknown disturbances. On one hand, by applying T-S fuzzy models to represent those modeled disturbances, a disturbance observer relying on T-S disturbance models can be constructed to track the dynamics of exogenous disturbances. On the other hand, L1 index is introduced to analyze the attenuation performance of disturbance for those unmodeled disturbances. By utilizing the existing convex optimization algorithm, a disturbance observer-based proportional-integral-controlled input is proposed such that the stability of hypersonic flight vehicles can be ensured and the tracking error for velocity and altitude in hypersonic flight vehicle models can converge to equilibrium point. Furthermore, the satisfactory disturbance rejection and attenuation with L1 index can be obtained simultaneously. Simulation results on hypersonic flight vehicle models can reflect the feasibility and effectiveness of the proposed control algorithm.

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

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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.

Relative tracking control of constellation satellites considering inter-satellite link

Science.gov (United States)

Fakoor, M.; Amozegary, F.; Bakhtiari, M.; Daneshjou, K.

2017-11-01

In this article, two main issues related to the large-scale relative motion of satellites in the constellation are investigated to establish the Inter Satellite Link (ISL) which means the dynamic and control problems. In the section related to dynamic problems, a detailed and effective analytical solution is initially provided for the problem of satellite relative motion considering perturbations. The direct geometric method utilizing spherical coordinates is employed to achieve this solution. The evaluation of simulation shows that the solution obtained from the geometric method calculates the relative motion of the satellite with high accuracy. Thus, the proposed analytical solution will be applicable and effective. In the section related to control problems, the relative tracking control system between two satellites will be designed in order to establish a communication link between the satellites utilizing analytical solution for relative motion of satellites with respect to the reference trajectory. Sliding mode control approach is employed to develop the relative tracking control system for body to body and payload to payload tracking control. Efficiency of sliding mode control approach is compared with PID and LQR controllers. Two types of payload to payload tracking control considering with and without payload degree of freedom are designed and suitable one for practical ISL applications is introduced. Also, Fuzzy controller is utilized to eliminate the control input in the sliding mode controller.

Robotic vehicle with multiple tracked mobility platforms

Science.gov (United States)

Salton, Jonathan R [Albuquerque, NM; Buttz, James H [Albuquerque, NM; Garretson, Justin [Albuquerque, NM; Hayward, David R [Wetmore, CO; Hobart, Clinton G [Albuquerque, NM; Deuel, Jr., Jamieson K.

2012-07-24

A robotic vehicle having two or more tracked mobility platforms that are mechanically linked together with a two-dimensional coupling, thereby forming a composite vehicle of increased mobility. The robotic vehicle is operative in hazardous environments and can be capable of semi-submersible operation. The robotic vehicle is capable of remote controlled operation via radio frequency and/or fiber optic communication link to a remote operator control unit. The tracks have a plurality of track-edge scallop cut-outs that allow the tracks to easily grab onto and roll across railroad tracks, especially when crossing the railroad tracks at an oblique angle.

Satellite tracking of threatened species

Science.gov (United States)

Williams, M.; Lunsford, A.; Ellis, D.; Robinson, J.; Coronado, P.; Campbell, W.

1998-01-01

In 1990, a joint effort of two U.S. federal agencies, NASA Goddard Space Flight Center (GSFC) and the Patuxent Wildlife Research Center, began. We initially joined forces in a project that used satellite telemetry to discover the winter home of a tiny dwindling population of Siberian Cranes. Since then several projects have emerged, and a web site was created to follow some of these activities. This web site is called the Satellite Tracking of Threatened Species and its location is http://sdcd.gsfc.nasa.gov/ISTO/satellite_tracking. It describes the overall program, and links you to three subsections that describe the projects in more detail: Satellite Direct Readout, Birdtracks, and Birdworld.

Pedestrian Tracking Based on Camshift with Kalman Prediction for Autonomous Vehicles

Directory of Open Access Journals (Sweden)

Lie Guo

2016-06-01

Full Text Available Pedestrian detection and tracking is the key to autonomous vehicle navigation systems avoiding potentially dangerous situations. Firstly, the probability distribution of colour information is established after a pedestrian is located in an image. Then the detected results are utilized to initialize a Kalman filter to predict the possible position of the pedestrian centroid in the future frame. A Camshift tracking algorithm is used to track the pedestrian in the specific search window of the next frame based on the prediction results. The actual position of the pedestrian centroid is output from the Camshift tracking algorithm to update the gain and error covariance matrix of the Kalman filter. Experimental results in real traffic situations show the proposed pedestrian tracking algorithm can achieve good performance even when they are partly occluded in inconsistent illumination circumstances.

Stability control for high speed tracked unmanned vehicles

Science.gov (United States)

Pape, Olivier; Morillon, Joel G.; Houbloup, Philippe; Leveque, Stephane; Fialaire, Cecile; Gauthier, Thierry; Ropars, Patrice

2005-05-01

The French Military Robotic Study Program (introduced in Aerosense 2003), sponsored by the French Defense Procurement Agency and managed by Thales as the prime contractor, focuses on about 15 robotic themes which can provide an immediate "operational add-on value". The paper details the "automatic speed adjustment" behavior (named SYR4), developed by Giat Industries Company, which main goal is to secure the teleoperated mobility of high speed tracked vehicles on rough grounds; more precisely, the validated low level behavior continuously adjusts the vehicle speed taking into account the teleperator wish AND the maximum speed that the vehicle can manage safely according to the commanded radius of curvature. The algorithm is based on a realistic physical model of the ground-tracks relation, taking into account many vehicle and ground parameters (such as ground adherence and dynamic specificities of tracked vehicles). It also deals with the teleoperator-machine interface, providing a balanced strategy between both extreme behaviors: a) maximum speed reduction before initiating the commanded curve; b) executing the minimum possible radius without decreasing the commanded speed. The paper presents the results got from the military acceptance tests performed on tracked SYRANO vehicle (French Operational Demonstrator).

Highlights of satellite-based forest change recognition and tracking using the ForWarn System

Science.gov (United States)

Steven P. Norman; William W. Hargrove; Joseph P. Spruce; William M. Christie; Sean W. Schroeder

2013-01-01

For a higher resolution version of this file, please use the following link: www.geobabble.orgSatellite-based remote sensing can assist forest managers with their need to recognize disturbances and track recovery. Despite the long...

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

Automated tracking for advanced satellite laser ranging systems

Science.gov (United States)

McGarry, Jan F.; Degnan, John J.; Titterton, Paul J., Sr.; Sweeney, Harold E.; Conklin, Brion P.; Dunn, Peter J.

1996-06-01

NASA's Satellite Laser Ranging Network was originally developed during the 1970's to track satellites carrying corner cube reflectors. Today eight NASA systems, achieving millimeter ranging precision, are part of a global network of more than 40 stations that track 17 international satellites. To meet the tracking demands of a steadily growing satellite constellation within existing resources, NASA is embarking on a major automation program. While manpower on the current systems will be reduced to a single operator, the fully automated SLR2000 system is being designed to operate for months without human intervention. Because SLR2000 must be eyesafe and operate in daylight, tracking is often performed in a low probability of detection and high noise environment. The goal is to automatically select the satellite, setup the tracking and ranging hardware, verify acquisition, and close the tracking loop to optimize data yield. TO accomplish the autotracking tasks, we are investigating (1) improved satellite force models, (2) more frequent updates of orbital ephemerides, (3) lunar laser ranging data processing techniques to distinguish satellite returns from noise, and (4) angular detection and search techniques to acquire the satellite. A Monte Carlo simulator has been developed to allow optimization of the autotracking algorithms by modeling the relevant system errors and then checking performance against system truth. A combination of simulator and preliminary field results will be presented.

A method for attitude measurement of a test vehicle based on the tracking of vectors

International Nuclear Information System (INIS)

Yang, Ning; Yang, Ming; Huo, Ju

2015-01-01

In the vehicle simulation test, in order to improve the measuring precision for the attitude of a test vehicle, a measuring method based on the vectors of light beams is presented, in which light beams are mounted on the test vehicle as the cooperation target, and the attitude of the test vehicle is calculated with the light beams’ vectors in the test vehicle’s coordinate system and the world coordinate system. Meanwhile, in order to expand the measuring range of the attitude parameters, cooperation targets and light beams in each cooperation target are increased. On this basis, the concept of an attitude calculation container is defined, and the selection method for the attitude calculation container that participates in the calculation is given. Simultaneously, the vectors of light beams are tracked so as to ensure the normal calculation of the attitude parameters. The experiments results show that this measuring method based on the tracking of vectors can achieve the high precision and wide range of measurement for the attitude of the test vehicle. (paper)

Air-Breathing Hypersonic Vehicle Tracking Control Based on Adaptive Dynamic Programming.

Science.gov (United States)

Mu, Chaoxu; Ni, Zhen; Sun, Changyin; He, Haibo

2017-03-01

In this paper, we propose a data-driven supplementary control approach with adaptive learning capability for air-breathing hypersonic vehicle tracking control based on action-dependent heuristic dynamic programming (ADHDP). The control action is generated by the combination of sliding mode control (SMC) and the ADHDP controller to track the desired velocity and the desired altitude. In particular, the ADHDP controller observes the differences between the actual velocity/altitude and the desired velocity/altitude, and then provides a supplementary control action accordingly. The ADHDP controller does not rely on the accurate mathematical model function and is data driven. Meanwhile, it is capable to adjust its parameters online over time under various working conditions, which is very suitable for hypersonic vehicle system with parameter uncertainties and disturbances. We verify the adaptive supplementary control approach versus the traditional SMC in the cruising flight, and provide three simulation studies to illustrate the improved performance with the proposed approach.

Emergency Brake for Tracked Vehicles

Science.gov (United States)

Green, G. L.; Hooper, S. L.

1986-01-01

Caliper brake automatically stops tracked vehicle as vehicle nears end of travel. Bar on vehicle, traveling to right, dislodges block between brake pads. Pads then press against bar, slowing vehicle by friction. Emergencybraking system suitable for elevators, amusement rides and machine tools.

A Region Tracking-Based Vehicle Detection Algorithm in Nighttime Traffic Scenes

Directory of Open Access Journals (Sweden)

Jianqiang Wang

2013-12-01

Full Text Available The preceding vehicles detection technique in nighttime traffic scenes is an important part of the advanced driver assistance system (ADAS. This paper proposes a region tracking-based vehicle detection algorithm via the image processing technique. First, the brightness of the taillights during nighttime is used as the typical feature, and we use the existing global detection algorithm to detect and pair the taillights. When the vehicle is detected, a time series analysis model is introduced to predict vehicle positions and the possible region (PR of the vehicle in the next frame. Then, the vehicle is only detected in the PR. This could reduce the detection time and avoid the false pairing between the bright spots in the PR and the bright spots out of the PR. Additionally, we present a thresholds updating method to make the thresholds adaptive. Finally, experimental studies are provided to demonstrate the application and substantiate the superiority of the proposed algorithm. The results show that the proposed algorithm can simultaneously reduce both the false negative detection rate and the false positive detection rate.

The Accuracy Assessment of Determining the Axis of Railway Track Basing on the Satellite Surveying

Science.gov (United States)

Koc, Władysław; Specht, Cezary; Chrostowski, Piotr; Palikowska, Katarzyna

2012-09-01

In 2009, at the Gdansk University of Technology there have been carried out, for the first time, continuous satellite surveying of railway track by the use of the relative phase method based on geodesic active network ASG-EUPOS and NAVGEO service. Still continuing research works focused on the GNSS multi-receivers platform evaluation for projecting and stock-taking. In order to assess the accuracy of the railway track axis position, the values of deviations of transverse position XTE (Cross Track Error) were evaluated. In order to eliminate the influence of random measurement errors and to obtain the coordinates representing the actual shape of the track, the XTE variable was analyzed by signal analysis methods (Chebyshev low-pass filtering and fast Fourier transform). At the end the paper presents the module of the computer software SATTRACK which currently has been developing at the Gdansk University of Technology. The program serves visualization, assessment and design process of railway track, adapted to the technique of continuous satellite surveying. The module called TRACK STRAIGHT is designed to assess the straight sections. A description of its operation as well as examples of its functions has been presented.

Terminal Sliding Mode Tracking Controller Design for Automatic Guided Vehicle

Science.gov (United States)

Chen, Hongbin

2018-03-01

Based on sliding mode variable structure control theory, the path tracking problem of automatic guided vehicle is studied, proposed a controller design method based on the terminal sliding mode. First of all, through analyzing the characteristics of the automatic guided vehicle movement, the kinematics model is presented. Then to improve the traditional expression of terminal sliding mode, design a nonlinear sliding mode which the convergence speed is faster than the former, verified by theoretical analysis, the design of sliding mode is steady and fast convergence in the limited time. Finally combining Lyapunov method to design the tracking control law of automatic guided vehicle, the controller can make the automatic guided vehicle track the desired trajectory in the global sense as well as in finite time. The simulation results verify the correctness and effectiveness of the control law.

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.

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.

Vehicle Detection with Occlusion Handling, Tracking, and OC-SVM Classification: A High Performance Vision-Based System

Science.gov (United States)

Velazquez-Pupo, Roxana; Sierra-Romero, Alberto; Torres-Roman, Deni; Shkvarko, Yuriy V.; Romero-Delgado, Misael

2018-01-01

This paper presents a high performance vision-based system with a single static camera for traffic surveillance, for moving vehicle detection with occlusion handling, tracking, counting, and One Class Support Vector Machine (OC-SVM) classification. In this approach, moving objects are first segmented from the background using the adaptive Gaussian Mixture Model (GMM). After that, several geometric features are extracted, such as vehicle area, height, width, centroid, and bounding box. As occlusion is present, an algorithm was implemented to reduce it. The tracking is performed with adaptive Kalman filter. Finally, the selected geometric features: estimated area, height, and width are used by different classifiers in order to sort vehicles into three classes: small, midsize, and large. Extensive experimental results in eight real traffic videos with more than 4000 ground truth vehicles have shown that the improved system can run in real time under an occlusion index of 0.312 and classify vehicles with a global detection rate or recall, precision, and F-measure of up to 98.190%, and an F-measure of up to 99.051% for midsize vehicles. PMID:29382078

GPS-based system for satellite tracking and geodesy

Science.gov (United States)

Bertiger, Willy I.; Thornton, Catherine L.

1989-01-01

High-performance receivers and data processing systems developed for GPS are reviewed. The GPS Inferred Positioning System (GIPSY) and the Orbiter Analysis and Simulation Software (OASIS) are described. The OASIS software is used to assess GPS system performance using GIPSY for data processing. Consideration is given to parameter estimation for multiday arcs, orbit repeatability, orbit prediction, daily baseline repeatability, agreement with VLBI, and ambiguity resolution. Also, the dual-frequency Rogue receiver, which can track up to eight GPS satellites simultaneously, is discussed.

Vehicle tracking based technique for radiation monitoring during nuclear or radiological emergency

International Nuclear Information System (INIS)

Saindane, Shashank S.; Otari, Anil D.; Suri, M.M.K.; Patil, S.S.; Pradeepkumar, K.S.; Sharma, D.N.

2010-01-01

Radiation Safety Systems Division, BARC has developed an advanced online radiation measurement cum vehicle tracking system for use. For the preparedness for response to any nuclear/radiological emergency scenario which may occur anywhere, the system designed is a Global System for Mobile (GSM) based Radiation Monitoring System (GRaMS) along with a Global Positioning System (GPS). It uses an energy compensated GM detector for radiation monitoring and is attached with commercially available Global Positioning System (GPS) for online acquisition of positional coordinates with time, and GSM modem for online data transfer to a remote control centre. The equipment can be operated continuously while the vehicle is moving

The limits of direct satellite tracking with the Global Positioning System (GPS)

Science.gov (United States)

Bertiger, W. I.; Yunck, T. P.

1988-01-01

Recent advances in high precision differential Global Positioning System-based satellite tracking can be applied to the more conventional direct tracking of low earth satellites. To properly evaluate the limiting accuracy of direct GPS-based tracking, it is necessary to account for the correlations between the a-priori errors in GPS states, Y-bias, and solar pressure parameters. These can be obtained by careful analysis of the GPS orbit determination process. The analysis indicates that sub-meter accuracy can be readily achieved for a user above 1000 km altitude, even when the user solution is obtained with data taken 12 hours after the data used in the GPS orbit solutions.

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.

Evaluating the accuracy of vehicle tracking data obtained from Unmanned Aerial Vehicles

Directory of Open Access Journals (Sweden)

Giuseppe Guido

2016-10-01

Full Text Available This paper presents a methodology for tracking moving vehicles that integrates Unmanned Aerial Vehicles with video processing techniques. The authors investigated the usefulness of Unmanned Aerial Vehicles to capture reliable individual vehicle data by using GPS technology as a benchmark. A video processing algorithm for vehicles trajectory acquisition is introduced. The algorithm is based on OpenCV libraries. In order to assess the accuracy of the proposed video processing algorithm an instrumented vehicle was equipped with a high precision GPS. The video capture experiments were performed in two case studies. From the field, about 24,000 positioning data were acquired for the analysis. The results of these experiments highlight the versatility of the Unmanned Aerial Vehicles technology combined with video processing technique in monitoring real traffic data.

Semi-active control of tracked vehicle suspension incorporating magnetorheological dampers

Science.gov (United States)

Ata, W. G.; Salem, A. M.

2017-05-01

In past years, the application of magnetorheological (MR) and electrorheological dampers in vehicle suspension has been widely studied, mainly for the purpose of vibration control. This paper presents theoretical study to identify an appropriate semi-active control method for MR-tracked vehicle suspension. Three representative control algorithms are simulated including the skyhook, hybrid and fuzzy-hybrid controllers. A seven degrees-of-freedom tracked vehicle suspension model incorporating MR dampers has been adopted for comparison between the performance of the three controllers. The model differential equations are derived based on Newton's second law of motion and the proposed control methods are developed. The performance of each control method under bump and sinusoidal road profiles for different vehicle speeds is simulated and compared with the performance of the conventional suspension system in time and frequency domains. The results show that the performance of tracked vehicle suspension with MR dampers is substantially improved. Moreover, the fuzzy-hybrid controller offers an excellent integrated performance in reducing the body accelerations as well as wheel bounce responses compared with the classical skyhook and hybrid controllers.

Tracking and data relay satellite system (TDRSS) capabilities

Science.gov (United States)

Spearing, R. E.

1985-10-01

The Tracking and Data Relay Satellite System (TDRSS) is the latest implementation to tracking and data acquisition network for near-earth orbiting satellite support designed to meet the requirements of the current and projected (to the year 2000) satellite user community. The TDRSS consists of a space segment (SS) and a ground segment (GS) that fit within NASA's Space Network (SN) complex controlled at the Goddard Space Flight Center. The SS currently employs a single satellite, TDRS-1, with two additional satellites to be deployed in January 1986 and July 1986. The GS contains the communications and equipment required to manage the three TDR satellites and to transmit and receive information to and from TDRSS user satellites. Diagrams and tables illustrating the TDRSS signal characteristics, the situation of TDRSS within the SN, the SN operations and element interrelationships, as well as future plans for new missions are included.

Reinforcement Learning–Based Energy Management Strategy for a Hybrid Electric Tracked Vehicle

Directory of Open Access Journals (Sweden)

Teng Liu

2015-07-01

Full Text Available This paper presents a reinforcement learning (RL–based energy management strategy for a hybrid electric tracked vehicle. A control-oriented model of the powertrain and vehicle dynamics is first established. According to the sample information of the experimental driving schedule, statistical characteristics at various velocities are determined by extracting the transition probability matrix of the power request. Two RL-based algorithms, namely Q-learning and Dyna algorithms, are applied to generate optimal control solutions. The two algorithms are simulated on the same driving schedule, and the simulation results are compared to clarify the merits and demerits of these algorithms. Although the Q-learning algorithm is faster (3 h than the Dyna algorithm (7 h, its fuel consumption is 1.7% higher than that of the Dyna algorithm. Furthermore, the Dyna algorithm registers approximately the same fuel consumption as the dynamic programming–based global optimal solution. The computational cost of the Dyna algorithm is substantially lower than that of the stochastic dynamic programming.

Probing the earth's gravity field by means of satellite-to-satellite tracking

Science.gov (United States)

Vonbun, F. O.

1977-01-01

Two satellite-to-satellite tracking (sst) tests are described in detail: (1) the ATS-6/Geos-3 and (2) the ATS-6/Apollo-Soyuz experiment. The main purpose of these two experiments was to track via ATS-6 the Geos-3, as well as the Apollo-Soyuz and to use these tracking data to determine both of the orbits at the same time, each of the orbits alone, and to test the two sst links to study local gravity anomalies. A second purpose was to test communications, command and data transmission from the ground via ATS-6 to these spacecraft and back again to the ground.

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.

Suborbital Reusable Launch Vehicles as an Opportunity to Consolidate and Calibrate Ground Based and Satellite Instruments

Science.gov (United States)

Papadopoulos, K.

2014-12-01

XCOR Aerospace, a commercial space company, is planning to provide frequent, low cost access to near-Earth space on the Lynx suborbital Reusable Launch Vehicle (sRLV). Measurements in the external vacuum environment can be made and can launch from most runways on a limited lead time. Lynx can operate as a platform to perform suborbital in situ measurements and remote sensing to supplement models and simulations with new data points. These measurements can serve as a quantitative link to existing instruments and be used as a basis to calibrate detectors on spacecraft. Easier access to suborbital data can improve the longevity and cohesiveness of spacecraft and ground-based resources. A study of how these measurements can be made on Lynx sRLV will be presented. At the boundary between terrestrial and space weather, measurements from instruments on Lynx can help develop algorithms to optimize the consolidation of ground and satellite based data as well as assimilate global models with new data points. For example, current tides and the equatorial electrojet, essential to understanding the Thermosphere-Ionosphere system, can be measured in situ frequently and on short notice. Furthermore, a negative-ion spectrometer and a Faraday cup, can take measurements of the D-region ion composition. A differential GPS receiver can infer the spatial gradient of ionospheric electron density. Instruments and optics on spacecraft degrade over time, leading to calibration drift. Lynx can be a cost effective platform for deploying a reference instrument to calibrate satellites with a frequent and fast turnaround and a successful return of the instrument. A calibrated reference instrument on Lynx can make collocated observations as another instrument and corrections are made for the latter, thus ensuring data consistency and mission longevity. Aboard a sRLV, atmospheric conditions that distort remotely sensed data (ground and spacecraft based) can be measured in situ. Moreover, an

Dynamic sensor tasking and IMM EKF estimation for tracking impulsively maneuvering satellites

Science.gov (United States)

Lace, Arthur A.

In order to efficiently maintain space situational awareness, care must be taken to optimally allocate expensive observation resources. In most situations the available sensors capable of tracking spacecraft have their time split between many different monitoring responsibilities. Tracking maneuvering spacecraft can be especially difficult as the schedule of maneuvers may not be known and will often throw off previous orbital models. Effectively solving this tasking problem is an ongoing focus of research in the area of space situational awareness. Most methods of automated tasking do not make use of interacting multiple model extended Kalman filter techniques to better track satellites during maneuvers. This paper proposes a modification to a Fisher information gain and estimated state covariance based sensor tasking method to take maneuver probability and multiple model dynamics into account. By incorporating the probabilistic maneuvering model, sensor tasking can be improved during satellite maneuvers using constrained resources. The proposed methods are verified through the use of numerical simulations with multiple maneuvering satellites and both orbital and ground-based sensors.

A linear complementarity method for the solution of vertical vehicle-track interaction

Science.gov (United States)

Zhang, Jian; Gao, Qiang; Wu, Feng; Zhong, Wan-Xie

2018-02-01

A new method is proposed for the solution of the vertical vehicle-track interaction including a separation between wheel and rail. The vehicle is modelled as a multi-body system using rigid bodies, and the track is treated as a three-layer beam model in which the rail is considered as an Euler-Bernoulli beam and both the sleepers and the ballast are represented by lumped masses. A linear complementarity formulation is directly established using a combination of the wheel-rail normal contact condition and the generalised-α method. This linear complementarity problem is solved using the Lemke algorithm, and the wheel-rail contact force can be obtained. Then the dynamic responses of the vehicle and the track are solved without iteration based on the generalised-α method. The same equations of motion for the vehicle and track are adopted at the different wheel-rail contact situations. This method can remove some restrictions, that is, time-dependent mass, damping and stiffness matrices of the coupled system, multiple equations of motion for the different contact situations and the effect of the contact stiffness. Numerical results demonstrate that the proposed method is effective for simulating the vehicle-track interaction including a separation between wheel and rail.

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.

A Leader-path-following formation system for AGVs with multi-sensor data fusion based vehicle tracking

Science.gov (United States)

Yao, Wen; Zhao, Xijun; Yu, Yufeng; Fang, Yongkun; Wang, Chao; Yang, Tianfu

2017-09-01

Caravans composed of vehicles with different functionality or trafficability raise the demand that formation system structure shall allow vehicles to deviate from the path to be followed when necessary. In this paper, a formation system is developed for autonomous ground vehicles (AGVs) who follow the path of a leader vehicle while retaining the ability of deviation from the reference path. In addition, it improves robustness of preceding vehicle localization by fusing Lidar tracking, camera tracking results with predecessor’s global position within an extended Kalman filter (EKF) in case that one or more sources of preceding vehicle localization is not reliable. The system is applied on real AGV platforms and won the 3rd place in an AGV competition in China.

A New Algorithm for ABS/GPS Integration Based on Fuzzy-Logic in Vehicle Navigation System

Directory of Open Access Journals (Sweden)

Ali Amin Zadeh

2011-10-01

Full Text Available GPS based vehicle navigation systems have difficulties in tracking vehicles in urban canyons due to poor satellite availability. ABS (Antilock Brake System Navigation System consists of self-contained optical encoders mounted on vehicle wheels that can continuously provide accurate short-term positioning information. In this paper, a new concept regarding GPS/ABS integration, based on Fuzzy Logic is presented. The proposed algorithm is used to identify GPS position accuracy based on environment and vehicle dynamic knowledge. The GPS is used as reference during the time it is in a good condition and replaced by ABS positioning system when GPS information is unreliable. We compare our proposed algorithm with other common algorithm in real environment. Our results show that the proposed algorithm can significantly improve the stability and reliability of ABS/GPS navigation system.

Bird migration and avian influenza: a comparison of hydrogen stable isotopes and satellite tracking methods

Science.gov (United States)

Bridge, Eli S.; Kelly, Jeffrey F.; Xiao, Xiangming; Takekawa, John Y.; Hill, Nichola J.; Yamage, Mat; Haque, Enam Ul; Islam, Mohammad Anwarul; Mundkur, Taej; Yavuz, Kiraz Erciyas; Leader, Paul; Leung, Connie Y.H.; Smith, Bena; Spragens, Kyle A.; Vandegrift, Kurt J.; Hosseini, Parviez R.; Saif, Samia; Mohsanin, Samiul; Mikolon, Andrea; Islam, Ausrafal; George, Acty; Sivananinthaperumal, Balachandran; Daszak, Peter; Newman, Scott H.

2014-01-01

Satellite-based tracking of migratory waterfowl is an important tool for understanding the potential role of wild birds in the long-distance transmission of highly pathogenic avian influenza. However, employing this technique on a continental scale is prohibitively expensive. This study explores the utility of stable isotope ratios in feathers in examining both the distances traveled by migratory birds and variation in migration behavior. We compared the satellite-derived movement data of 22 ducks from 8 species captured at wintering areas in Bangladesh, Turkey, and Hong Kong with deuterium ratios (δD) in the feathers of these and other individuals captured at the same locations. We derived likely molting locations from the satellite tracking data and generated expected isotope ratios based on an interpolated map of δD in rainwater. Although δD was correlated with the distance between wintering and molting locations, surprisingly, measured δD values were not correlated with either expected values or latitudes of molting sites. However, population-level parameters derived from the satellite-tracking data, such as mean distance between wintering and molting locations and variation in migration distance, were reflected by means and variation of the stable isotope values. Our findings call into question the relevance of the rainfall isotope map for Asia for linking feather isotopes to molting locations, and underscore the need for extensive ground truthing in the form of feather-based isoscapes. Nevertheless, stable isotopes from feathers could inform disease models by characterizing the degree to which regional breeding populations interact at common wintering locations. Feather isotopes also could aid in surveying wintering locations to determine where high-resolution tracking techniques (e.g. satellite tracking) could most effectively be employed. Moreover, intrinsic markers such as stable isotopes offer the only means of inferring movement information from

Tracking System : Suaineadh satellite experiment

OpenAIRE

Brengesjö, Carl; Selin, Martine

2011-01-01

The purpose of this bachelor thesis is to present a tracking system for the Suaineadh satellite experiment. The experiment is a part of the REXUS (Rocket EXperiments for University Students) program and the objective is to deploy a foldable web in space. The assignment of this thesis is to develop a tracking system to find the parts from the Suaineadh experiment that will land on Earth. It is important to find the parts and recover all the data that the experiment performed during the travel ...

Comparative Analysis of Lightweight Robotic Wheeled and Tracked Vehicle

OpenAIRE

Johnson, Christopher Patrick

2012-01-01

This study focuses on conducting a benchmarking analysis for light wheeled and tracked robotic vehicles. Vehicle mobility has long been a key aspect of research for many organizations. According to the Department of Defense vehicle mobility is defined as, "the overall capacity to move from place to place while retaining its ability to perform its primary mission"[1]. Until recently this definition has been applied exclusively to large scale wheeled and tracked vehicles. With new development l...

Ground Simulation of an Autonomous Satellite Rendezvous and Tracking System Using Dual Robotic Systems

Science.gov (United States)

Trube, Matthew J.; Hyslop, Andrew M.; Carignan, Craig R.; Easley, Joseph W.

2012-01-01

A hardware-in-the-loop ground system was developed for simulating a robotic servicer spacecraft tracking a target satellite at short range. A relative navigation sensor package "Argon" is mounted on the end-effector of a Fanuc 430 manipulator, which functions as the base platform of the robotic spacecraft servicer. Machine vision algorithms estimate the pose of the target spacecraft, mounted on a Rotopod R-2000 platform, relay the solution to a simulation of the servicer spacecraft running in "Freespace", which performs guidance, navigation and control functions, integrates dynamics, and issues motion commands to a Fanuc platform controller so that it tracks the simulated servicer spacecraft. Results will be reviewed for several satellite motion scenarios at different ranges. Key words: robotics, satellite, servicing, guidance, navigation, tracking, control, docking.

Commercial vehicle route tracking using video detection.

Science.gov (United States)

2010-10-31

Interstate commercial vehicle traffic is a major factor in the life of any road surface. The ability to track : these vehicles and their routes through the state can provide valuable information to planning : activities. We propose a method using vid...

Fuzzy path tracking and position estimation of autonomous vehicles using differential GPS

OpenAIRE

Rodríguez Castaño, Ángel; Heredia Benot, José Guillermo; Ollero Baturone, Aníbal

2000-01-01

This paper presents an autonomous vehicle position estimation system based on GPS, that uses a fuzzy sensor fusion technique. A fuzzy path tracking algorithm is also proposed. Both systems have been implemented in the ROMEO-4R vehicle developed at the University of Seville.

Design of tracking mount and controller for mobile satellite laser ranging system

Science.gov (United States)

Park, Cheol Hoon; Son, Young Su; Kim, Byung In; Ham, Sang Young; Lee, Sung Whee; Lim, Hyung Chul

2012-01-01

In this study, we have proposed and implemented a design for the tracking mount and controller of the ARGO-M (Accurate Ranging system for Geodetic Observation - Mobile) which is a mobile satellite laser ranging (SLR) system developed by the Korea Astronomy and Space Science Institute (KASI) and Korea Institute of Machinery and Materials (KIMM). The tracking mount comprises a few core components such as bearings, driving motors and encoders. These components were selected as per the technical specifications for the tracking mount of the ARGO-M. A three-dimensional model of the tracking mount was designed. The frequency analysis of the model predicted that the first natural frequency of the designed tracking mount was high enough. The tracking controller is simulated using MATLAB/xPC Target to achieve the required pointing and tracking accuracy. In order to evaluate the system repeatability and tracking accuracy of the tracking mount, a prototype of the ARGO-M was fabricated, and repeatability tests were carried out using a laser interferometer. Tracking tests were conducted using the trajectories of low earth orbit (LEO) and high earth orbit (HEO) satellites. Based on the test results, it was confirmed that the prototype of the tracking mount and controller of the ARGO-M could achieve the required repeatability along with a tracking accuracy of less than 1 arcsec.

Blossom Point Satellite Tracking and Command Station

Data.gov (United States)

Federal Laboratory Consortium — FUNCTION: The Blossom Point Satellite Command and Tracking Facility (BP) provides engineering and operational support to several complex space systems for the Navy...

Parametric fault estimation based on H∞ optimization in a satellite launch vehicle

DEFF Research Database (Denmark)

Soltani, Mohsen; Izadi-Zamanabadi, Roozbeh; Stoustrup, Jakob

2008-01-01

Correct diagnosis under harsh environmental conditions is crucial for space vehiclespsila health management systems to avoid possible hazardous situations. Consequently, the diagnosis methods are required to be robust toward these conditions. Design of a parametric fault detector, where the fault...... for the satellite launch vehicle and the results are discussed....

Orbit and clock determination of BDS regional navigation satellite system based on IGS M-GEX and WHU BETS tracking network

Science.gov (United States)

GENG, T.; Zhao, Q.; Shi, C.; Shum, C.; Guo, J.; Su, X.

2013-12-01

BeiDou Navigation Satellite System (BDS) began to provide the regional open service on December 27th 2012 and will provide the global open service by the end of 2020. Compared to GPS, the space segment of BDS Regional System consists of 5 Geostationary Earth Orbit satellites (GEO), 5 Inclined Geosynchronous Orbit satellites (IGSO) and 4 Medium Earth orbit (MEO) satellites. Since 2011, IGS Multiple-GNSS Experiment (M-GEX) focuses on tracking the newly available GNSS signals. This includes all signals from the modernized satellites of the GPS and GLONASS systems, as well as signals of the BDS, Galileo and QZSS systems. Up to now, BDS satellites are tracked by around 25 stations with a variety of different antennas and receivers from different GNSS manufacture communities in M-GEX network. Meanwhile, there are 17 stations with Unicore Communications Incorporation's GPS/BDS receivers in BeiDou Experimental Tracking Stations (BETS) network by Wuhan University. In addition, 5 BDS satellites have been tracking by the International Laser Ranging Service (ILRS). BDS performance is expected to be further studied by the GNSS communities. Following an introduction of the BDS system and above different tracking network, this paper discusses the achieved BDS characterization and performance assessment. Firstly, the BDS signal and measurement quality are analyzed with different antennas and receivers in detail compared to GPS. This includes depth of coverage for satellite observation, carrier-to-noise-density ratios, code noise and multipath, carrier phase errors. Secondly, BDS Precise Orbit Determination (POD) is processed. Different arc lengths and sets of orbit parameters are tested using Position And Navigation Data Analysis software (PANDA) which is developed at the Wuhan University. GEO, IGSO and MEO satellites orbit quality will be assessed using overlap comparison, 2-day orbit fit and external validations with Satellite Laser Range (SLR). Then BDS satellites are equipped

Parking Space Detection and Trajectory Tracking Control for Vehicle Auto-Parking

OpenAIRE

Shiuh-Jer Huang; Yu-Sheng Hsu

2017-01-01

On-board available parking space detecting system, parking trajectory planning and tracking control mechanism are the key components of vehicle backward auto-parking system. Firstly, pair of ultrasonic sensors is installed on each side of vehicle body surface to detect the relative distance between ego-car and surrounding obstacle. The dimension of a found empty space can be calculated based on vehicle speed and the time history of ultrasonic sensor detecting information. This result can be u...

Real-Time Vehicle Speed Estimation Based on License Plate Tracking in Monocular Video Sequences

Directory of Open Access Journals (Sweden)

Aleksej MAKAROV

2016-02-01

Full Text Available A method of estimating the vehicle speed from images obtained by a fixed over-the-road monocular camera is presented. The method is based on detecting and tracking vehicle license plates. The contrast between the license plate and its surroundings is enhanced using infrared light emitting diodes and infrared camera filters. A range of the license plate height values is assumed a priori. The camera vertical angle of view is measured prior to installation. The camera tilt is continuously measured by a micro-electromechanical sensor. The distance of the license plate from the camera is theoretically derived in terms of its pixel coordinates. Inaccuracies due to the frame rate drift, to the tilt and the angle of view measurement errors, to edge pixel detection and to a coarse assumption of the vehicle license plate height are analyzed and theoretically formulated. The resulting system is computationally efficient, inexpensive and easy to install and maintain along with the existing ALPR cameras.

A Novel SHLNN Based Robust Control and Tracking Method for Hypersonic Vehicle under Parameter Uncertainty

Directory of Open Access Journals (Sweden)

Chuanfeng Li

2017-01-01

Full Text Available Hypersonic vehicle is a typical parameter uncertain system with significant characteristics of strong coupling, nonlinearity, and external disturbance. In this paper, a combined system modeling approach is proposed to approximate the actual vehicle system. The state feedback control strategy is adopted based on the robust guaranteed cost control (RGCC theory, where the Lyapunov function is applied to get control law for nonlinear system and the problem is transformed into a feasible solution by linear matrix inequalities (LMI method. In addition, a nonfragile guaranteed cost controller solved by LMI optimization approach is employed to the linear error system, where a single hidden layer neural network (SHLNN is employed as an additive gain compensator to reduce excessive performance caused by perturbations and uncertainties. Simulation results show the stability and well tracking performance for the proposed strategy in controlling the vehicle system.

A model predictive control approach combined unscented Kalman filter vehicle state estimation in intelligent vehicle trajectory tracking

Directory of Open Access Journals (Sweden)

Hongxiao Yu

2015-05-01

Full Text Available Trajectory tracking and state estimation are significant in the motion planning and intelligent vehicle control. This article focuses on the model predictive control approach for the trajectory tracking of the intelligent vehicles and state estimation of the nonlinear vehicle system. The constraints of the system states are considered when applying the model predictive control method to the practical problem, while 4-degree-of-freedom vehicle model and unscented Kalman filter are proposed to estimate the vehicle states. The estimated states of the vehicle are used to provide model predictive control with real-time control and judge vehicle stability. Furthermore, in order to decrease the cost of solving the nonlinear optimization, the linear time-varying model predictive control is used at each time step. The effectiveness of the proposed vehicle state estimation and model predictive control method is tested by driving simulator. The results of simulations and experiments show that great and robust performance is achieved for trajectory tracking and state estimation in different scenarios.

Probing the earth's gravity field using Satellite-to-Satellite Tracking (SST)

Science.gov (United States)

Vonbun, F. O.

1976-01-01

Satellite-to-Satellite (SST) tests, namely: (a) the ATS-6/GEOS-3 and (b) the ATS-6/Apollo-Soyuz experiment and some of the results obtained are described. The main purpose of these two experiments was first to track via ATS-6 the GEOS-3 as well as the Apollo-Soyuz and to use these tracking data to determine (a) both orbits, that is, ATS-6, GEOS-3 and/or the Apollo-Soyuz orbits at the same time; (b) each of these orbits alone; and (c) test the ATS-6/GEOS-3 and/or Apollo-Soyuz SST link to study local gravity anomalies; and, second, to test communications, command, and data transmission from the ground via ATS-6 to these spacecraft and back again to the ground. The Apollo-Soyuz Geodynamics Experiment is discussed in some detail.

Underground vehicle monitoring and material tracking by wireless data transmission; Untertaegige Fahrzeugueberwachung und Materialverfolgung mittels drahtloser Datenuebertragung

Energy Technology Data Exchange (ETDEWEB)

Huenefeld, R. [Technische Hochschule Aachen (Germany). Lehrstuhl und Inst. fuer Bergwerks- und Huettenmaschinenkunde; Kuepper, T. [XGraphic Ingenieurgesellschaft mbH, Aachen (Germany)

2008-04-17

Satellite-assisted navigation and position detection by GPS (Global Positioning System) are the state of the art in surface fleet management. The system cannot, of course, be used underground. With the introduction of WLAN networks, pocket PCs and WLAN Handys a technological platform, on the basis of which comparable services can be offered, has meanwhile become available also in the underground mining industry. Various applications, which were developed for the specified technological environment, are described in this contribution. They are used for communication, vehicle monitoring and position tracking, but are also suitable for complicated tasks. A typical example is the automation of monorails, in which communication with the vehicle and visualisation of the vehicle data and position are important. (orig.)

Integrating small satellite communication in an autonomous vehicle network: A case for oceanography

Science.gov (United States)

Guerra, André G. C.; Ferreira, António Sérgio; Costa, Maria; Nodar-López, Diego; Aguado Agelet, Fernando

2018-04-01

Small satellites and autonomous vehicles have greatly evolved in the last few decades. Hundreds of small satellites have been launched with increasing functionalities, in the last few years. Likewise, numerous autonomous vehicles have been built, with decreasing costs and form-factor payloads. Here we focus on combining these two multifaceted assets in an incremental way, with an ultimate goal of alleviating the logistical expenses in remote oceanographic operations. The first goal is to create a highly reliable and constantly available communication link for a network of autonomous vehicles, taking advantage of the small satellite lower cost, with respect to conventional spacecraft, and its higher flexibility. We have developed a test platform as a proving ground for this network, by integrating a satellite software defined radio on an unmanned air vehicle, creating a system of systems, and several tests have been run successfully, over land. As soon as the satellite is fully operational, we will start to move towards a cooperative network of autonomous vehicles and small satellites, with application in maritime operations, both in-situ and remote sensing.

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.

High Precision Control of Ship-Mounted Satellite Tracking Antenna

DEFF Research Database (Denmark)

Mohsen, Soltani; Izadi-Zamanabadi, Roozbeh; Wisniewski, Rafal

2007-01-01

The telecommunication on a modern merchandise ship is maintained by means of satellite communication. The task of the tracking system is to position the on-board antenna toward a chosen satellite. The control system is capable of rejecting the external disturbances which affect on the under...

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

International Nuclear Information System (INIS)

Dohner, J.L.

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

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.

Design of a Path-Tracking Steering Controller for Autonomous Vehicles

Directory of Open Access Journals (Sweden)

Chuanyang Sun

2018-06-01

Full Text Available This paper presents a linearization method for the vehicle and tire models under the model predictive control (MPC scheme, and proposes a linear model-based MPC path-tracking steering controller for autonomous vehicles. The steering controller is designed to minimize lateral path-tracking deviation at high speeds. The vehicle model is linearized by a sequence of supposed steering angles, which are obtained by assuming the vehicle can reach the desired path at the end of the MPC prediction horizon and stay in a steady-state condition. The lateral force of the front tire is directly used as the control input of the model, and the rear tire’s lateral force is linearized by an equivalent cornering stiffness. The course-direction deviation, which is the angle between the velocity vector and the path heading, is chosen as a control reference state. The linearization model is validated through the simulation, and the results show high prediction accuracy even in regions of large steering angle. This steering controller is tested through simulations on the CarSim-Simulink platform (R2013b, MathWorks, Natick, MA, USA, showing the improved performance of the present controller at high speeds.

Dynamic Modeling and Simulation of Marine Satellite Tracking Antenna Using Lagrange Method

DEFF Research Database (Denmark)

Wang, Yunlong; Soltani, Mohsen; Hussain, Dil muhammed Akbar

2016-01-01

Marine Satellite Tracking Antenna (MSTA) is a necessary device in ships for receiving satellite signals when they are sailing on the sea. This paper presents a simple methodology to obtain the dynamic equations of MSTA through Lagrange method, which is fundamental in design of modelbased controll......Marine Satellite Tracking Antenna (MSTA) is a necessary device in ships for receiving satellite signals when they are sailing on the sea. This paper presents a simple methodology to obtain the dynamic equations of MSTA through Lagrange method, which is fundamental in design of modelbased...

Dynamics of a railway vehicle on a laterally disturbed track

DEFF Research Database (Denmark)

Christiansen, Lasse Engbo; True, Hans

2017-01-01

In this article a theoretical investigation of the dynamics of a railway bogie running on a tangent track with a periodic disturbance of the lateral track geometry is presented. The dynamics is computed for two values of the speed of the vehicle in combination with different values of the wavelen......In this article a theoretical investigation of the dynamics of a railway bogie running on a tangent track with a periodic disturbance of the lateral track geometry is presented. The dynamics is computed for two values of the speed of the vehicle in combination with different values...

A model predictive speed tracking control approach for autonomous ground vehicles

Science.gov (United States)

Zhu, Min; Chen, Huiyan; Xiong, Guangming

2017-03-01

This paper presents a novel speed tracking control approach based on a model predictive control (MPC) framework for autonomous ground vehicles. A switching algorithm without calibration is proposed to determine the drive or brake control. Combined with a simple inverse longitudinal vehicle model and adaptive regulation of MPC, this algorithm can make use of the engine brake torque for various driving conditions and avoid high frequency oscillations automatically. A simplified quadratic program (QP) solving algorithm is used to reduce the computational time, and the approach has been applied in a 16-bit microcontroller. The performance of the proposed approach is evaluated via simulations and vehicle tests, which were carried out in a range of speed-profile tracking tasks. With a well-designed system structure, high-precision speed control is achieved. The system can robustly model uncertainty and external disturbances, and yields a faster response with less overshoot than a PI controller.

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.

Kalman filter-based tracking of moving objects using linear ultrasonic sensor array for road vehicles

Science.gov (United States)

Li, Shengbo Eben; Li, Guofa; Yu, Jiaying; Liu, Chang; Cheng, Bo; Wang, Jianqiang; Li, Keqiang

2018-01-01

Detection and tracking of objects in the side-near-field has attracted much attention for the development of advanced driver assistance systems. This paper presents a cost-effective approach to track moving objects around vehicles using linearly arrayed ultrasonic sensors. To understand the detection characteristics of a single sensor, an empirical detection model was developed considering the shapes and surface materials of various detected objects. Eight sensors were arrayed linearly to expand the detection range for further application in traffic environment recognition. Two types of tracking algorithms, including an Extended Kalman filter (EKF) and an Unscented Kalman filter (UKF), for the sensor array were designed for dynamic object tracking. The ultrasonic sensor array was designed to have two types of fire sequences: mutual firing or serial firing. The effectiveness of the designed algorithms were verified in two typical driving scenarios: passing intersections with traffic sign poles or street lights, and overtaking another vehicle. Experimental results showed that both EKF and UKF had more precise tracking position and smaller RMSE (root mean square error) than a traditional triangular positioning method. The effectiveness also encourages the application of cost-effective ultrasonic sensors in the near-field environment perception in autonomous driving systems.

A Two-Dimensional Solar Tracking Stationary Guidance Method Based on Feature-Based Time Series

Directory of Open Access Journals (Sweden)

Keke Zhang

2018-01-01

Full Text Available The amount of satellite energy acquired has a direct impact on operational capacities of the satellite. As for practical high functional density microsatellites, solar tracking guidance design of solar panels plays an extremely important role. Targeted at stationary tracking problems incurred in a new system that utilizes panels mounted in the two-dimensional turntable to acquire energies to the greatest extent, a two-dimensional solar tracking stationary guidance method based on feature-based time series was proposed under the constraint of limited satellite attitude coupling control capability. By analyzing solar vector variation characteristics within an orbit period and solar vector changes within the whole life cycle, such a method could be adopted to establish a two-dimensional solar tracking guidance model based on the feature-based time series to realize automatic switching of feature-based time series and stationary guidance under the circumstance of different β angles and the maximum angular velocity control, which was applicable to near-earth orbits of all orbital inclination. It was employed to design a two-dimensional solar tracking stationary guidance system, and a mathematical simulation for guidance performance was carried out in diverse conditions under the background of in-orbit application. The simulation results show that the solar tracking accuracy of two-dimensional stationary guidance reaches 10∘ and below under the integrated constraints, which meet engineering application requirements.

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.

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.

Nonlinear Uncertainty Propagation of Satellite State Error for Tracking and Conjunction Risk Assessment

Science.gov (United States)

2017-12-18

AFRL-RV-PS- AFRL-RV-PS- TR-2017-0177 TR-2017-0177 NONLINEAR UNCERTAINTY PROPAGATION OF SATELLITE STATE ERROR FOR TRACKING AND CONJUNCTION RISK...Uncertainty Propagation of Satellite State Error for Tracking and Conjunction Risk Assessment 5a. CONTRACT NUMBER FA9453-16-1-0084 5b. GRANT NUMBER...prediction and satellite conjunction analysis. Statistical approach utilizes novel methods to build better uncertainty state characterization in the context

Laser technology for high precision satellite tracking

Science.gov (United States)

Plotkin, H. H.

1974-01-01

Fixed and mobile laser ranging stations have been developed to track satellites equipped with retro-reflector arrays. These have operated consistently at data rates of once per second with range precision better than 50 cm, using Q-switched ruby lasers with pulse durations of 20 to 40 nanoseconds. Improvements are being incorporated to improve the precision to 10 cm, and to permit ranging to more distant satellites. These include improved reflector array designs, processing and analysis of the received reflection pulses, and use of sub-nanosecond pulse duration lasers.

FDTD Seismic Simulation of Moving Tracked Vehicle

National Research Council Canada - National Science Library

Ketcham, Stephen

2000-01-01

This paper describes the utility of a large finite-difference time domain (FDTD) simulation of seismic wave propagation from a spatially and time varying source that generically represents a moving tracked vehicle...

Gravity model improvement using the DORIS tracking system on the SPOT 2 satellite

Science.gov (United States)

Nerem, R. S.; Lerch, F. J.; Williamson, R. G.; Klosko, S. M.; Robbins, J. W.; Patel, G. B.

1994-01-01

A high-precision radiometric satellite tracking system, Doppler Orbitography and Radio-positioning Integrated by Satellite system (DORIS), has recently been developed by the French space agency, Centre National d'Etudes Spatiales (CNES). DORIS was designed to provide tracking support for missions such as the joint United States/French TOPEX/Poseidon. As part of the flight testing process, a DORIS package was flown on the French SPOT 2 satellite. A substantial quantity of geodetic quality tracking data was obtained on SPOT 2 from an extensive international DORIS tracking network. These data were analyzed to assess their accuracy and to evaluate the gravitational modeling enhancements provided by these data in combination with the Goddard Earth Model-T3 (GEM-T3) gravitational model. These observations have noise levels of 0.4 to 0.5 mm/s, with few residual systematic effects. Although the SPOT 2 satellite experiences high atmospheric drag forces, the precision and global coverage of the DORIS tracking data have enabled more extensive orbit parameterization to mitigate these effects. As a result, the SPOT 2 orbital errors have been reduced to an estimated radial accuracy in the 10-20 cm RMS range. The addition of these data, which encompass many regions heretofore lacking in precision satellite tracking, has significantly improved GEM-T3 and allowed greatly improved orbit accuracies for Sun-synchronous satellites like SPOT 2 (such as ERS 1 and EOS). Comparison of the ensuing gravity model with other contemporary fields (GRIM-4C2, TEG2B, and OSU91A) provides a means to assess the current state of knowledge of the Earth's gravity field. Thus, the DORIS experiment on SPOT 2 has provided a strong basis for evaluating this new orbit tracking technology and has demonstrated the important contribution of the DORIS network to the success of the TOPEX/Poseidon mission.

GPS-based tracking system for TOPEX orbit determination

Science.gov (United States)

Melbourne, W. G.

1984-01-01

A tracking system concept is discussed that is based on the utilization of the constellation of Navstar satellites in the Global Positioning System (GPS). The concept involves simultaneous and continuous metric tracking of the signals from all visible Navstar satellites by approximately six globally distributed ground terminals and by the TOPEX spacecraft at 1300-km altitude. Error studies indicate that this system could be capable of obtaining decimeter position accuracies and, most importantly, around 5 cm in the radial component which is key to exploiting the full accuracy potential of the altimetric measurements for ocean topography. Topics covered include: background of the GPS, the precision mode for utilization of the system, past JPL research for using the GPS in precision applications, the present tracking system concept for high accuracy satellite positioning, and results from a proof-of-concept demonstration.

Reliability analysis of high-speed tracked vehicles in the polish army

Directory of Open Access Journals (Sweden)

Kończak Jarosław

2017-06-01

Full Text Available The Polish Armed Forces use tracked vehicles that serve as a core element of the ground combat forces. These vehicles are capable of fighting in all kinds of terrain conditions, in any season of the year. Combat missions are often fought in areas where even no dirt roads are available. The present paper assesses the reliability of tracked vehicles in the context of their irregular operation, as well as service- and maintenance-related vulnerability.

Comparison of different "along the track" high resolution satellite stereo-pair for DSM extraction

Science.gov (United States)

Nikolakopoulos, Konstantinos G.

2013-10-01

The possibility to create DEM from stereo pairs is based on the Pythagoras theorem and on the principles of photogrammetry that are applied to aerial photographs stereo pairs for the last seventy years. The application of these principles to digital satellite stereo data was inherent in the first satellite missions. During the last decades the satellite stereo-pairs were acquired across the track in different days (SPOT, ERS etc.). More recently the same-date along the track stereo-data acquisition seems to prevail (Terra ASTER, SPOT5 HRS, Cartosat, ALOS Prism) as it reduces the radiometric image variations (refractive effects, sun illumination, temporal changes) and thus increases the correlation success rate in any image matching.Two of the newest satellite sensors with stereo collection capability is Cartosat and ALOS Prism. Both of them acquire stereopairs along the track with a 2,5m spatial resolution covering areas of 30X30km. In this study we compare two different satellite stereo-pair collected along the track for DSM creation. The first one is created from a Cartosat stereopair and the second one from an ALOS PRISM triplet. The area of study is situated in Chalkidiki Peninsula, Greece. Both DEMs were created using the same ground control points collected with a Differential GPS. After a first control for random or systematic errors a statistical analysis was done. Points of certified elevation have been used to estimate the accuracy of these two DSMs. The elevation difference between the different DEMs was calculated. 2D RMSE, correlation and the percentile value were also computed and the results are presented.

Multiple Model-Based Synchronization Approaches for Time Delayed Slaving Data in a Space Launch Vehicle Tracking System

Directory of Open Access Journals (Sweden)

Haryong Song

2016-01-01

Full Text Available Due to the inherent characteristics of the flight mission of a space launch vehicle (SLV, which is required to fly over very large distances and have very high fault tolerances, in general, SLV tracking systems (TSs comprise multiple heterogeneous sensors such as radars, GPS, INS, and electrooptical targeting systems installed over widespread areas. To track an SLV without interruption and to hand over the measurement coverage between TSs properly, the mission control system (MCS transfers slaving data to each TS through mission networks. When serious network delays occur, however, the slaving data from the MCS can lead to the failure of the TS. To address this problem, in this paper, we propose multiple model-based synchronization (MMS approaches, which take advantage of the multiple motion models of an SLV. Cubic spline extrapolation, prediction through an α-β-γ filter, and a single model Kalman filter are presented as benchmark approaches. We demonstrate the synchronization accuracy and effectiveness of the proposed MMS approaches using the Monte Carlo simulation with the nominal trajectory data of Korea Space Launch Vehicle-I.

Comparing autonomous underwater vehicle (AUV) and vessel-based tracking performance for locating acoustically tagged fish

OpenAIRE

Eiler, John H.; Grothues, Thomas M.; Dobarro, Joseph A.; Masuda, Michele M.

2013-01-01

Autonomous underwater vehicles (AUV’s) are increasingly used to collect physical, chemical, and biological information in the marine environment. Recent efforts include merging AUV technology with acoustic telemetry to provide information on the distribution and movements of marine fish. We compared surface vessel and AUV tracking capabilities under rigorous conditions in coastal waters near Juneau, Alaska. Tracking surveys were conducted with a REMUS 100 AUV equipped with an integrated acous...

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.

On-Line Path Generation and Tracking for High-Speed Wheeled Autonomous Vehicles

Science.gov (United States)

2006-02-17

On-Line Path Generation and Tracking for High-Speed Wheeled Autonomous Vehicles Report Title ABSTRACT In this work we proposed two semi-analytic...298-102 Enclosure 1 On-Line Path Generation and Tracking for High-Speed Wheeled Autonomous Vehicles by...Specifically, the following problems will be addressed during this project: 2.1 Challenges The problem of trajectory planning for high-speed autonomous vehicles is

A Semiactive and Adaptive Hybrid Control System for a Tracked Vehicle Hydropneumatic Suspension Based on Disturbance Identification

Directory of Open Access Journals (Sweden)

Shousong Han

2017-01-01

Full Text Available The riding conditions for a high-speed tracked vehicle are quite complex. To enhance the adaptability of suspension systems to different riding conditions, a semiactive and self-adaptive hybrid control strategy based on disturbance velocity and frequency identification was proposed. A mathematical model of the semiactive, self-adaptive hybrid suspension control system, along with a performance evaluation function, was established. Based on a two-degree-of-freedom (DOF suspension system, the kinematic relations and frequency zero-crossing detection method were defined, and expressions for the disturbance velocity and disturbance frequency of the road were obtained. Optimal scheduling of the semiactive hybrid damping control gain (csky, cground, chybrid and self-adaptive control gain (cv under different disturbances were realized by exploiting the particle swarm multiobjective optimization algorithm. An experimental study using a carefully designed test rig was performed under a number of typical riding conditions of tracked vehicles, and the results showed that the proposed control strategy is capable of accurately recognizing different disturbances, shifting between control modes (semiactive/self-adaptive, and scheduling the damping control gain according to the disturbance identification outcomes; hence, the proposed strategy could achieve a good trade-off between ride comfort and ride safety and efficiently increase the overall performance of the suspension under various riding conditions.

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

Independent review : statistical analyses of relationship between vehicle curb weight, track width, wheelbase and fatality rates.

Science.gov (United States)

2011-03-01

"NHTSA selected the vehicle footprint (the measure of a vehicles wheelbase multiplied by its average track width) as the attribute upon which to base the CAFE standards for model year 2012-2016 passenger cars and light trucks. These standards are ...

The integrated satellite-acoustic telemetry (iSAT) system for tracking marine megafauna

KAUST Repository

De la Torre, Pedro

2012-10-06

This document describes the integrated satellite-acoustic telemetry (iSAT) system: an autonomous modular system for tracking the movements of large pelagic fish using acoustic telemetry and satellite communications. The sensor platform is described along with the propulsion and navigation systems. An application for tracking the whale shark (Rhincodon typus) in the Red Sea is included along with a discussion of the technical difficulties that such a system faces.

The integrated satellite-acoustic telemetry (iSAT) system for tracking marine megafauna

KAUST Repository

De la Torre, Pedro; Berumen, Michael L.; Salama, Khaled N.; Smith, E. Lloyd

2012-01-01

This document describes the integrated satellite-acoustic telemetry (iSAT) system: an autonomous modular system for tracking the movements of large pelagic fish using acoustic telemetry and satellite communications. The sensor platform is described along with the propulsion and navigation systems. An application for tracking the whale shark (Rhincodon typus) in the Red Sea is included along with a discussion of the technical difficulties that such a system faces.

Trajectory Tracking of a Tri-Rotor Aerial Vehicle Using an MRAC-Based Robust Hybrid Control Algorithm

Directory of Open Access Journals (Sweden)

Zain Anwar Ali

2017-01-01

Full Text Available In this paper, a novel Model Reference Adaptive Control (MRAC-based hybrid control algorithm is presented for the trajectory tracking of a tri-rotor Unmanned Aerial Vehicle (UAV. The mathematical model of the tri-rotor is based on the Newton–Euler formula, whereas the MRAC-based hybrid controller consists of Fuzzy Proportional Integral Derivative (F-PID and Fuzzy Proportional Derivative (F-PD controllers. MRAC is used as the main controller for the dynamics, while the parameters of the adaptive controller are fine-tuned by the F-PD controller for the altitude control subsystem and the F-PID controller for the attitude control subsystem of the UAV. The stability of the system is ensured and proven by Lyapunov stability analysis. The proposed control algorithm is tested and verified using computer simulations for the trajectory tracking of the desired path as an input. The effectiveness of our proposed algorithm is compared with F-PID and the Fuzzy Logic Controller (FLC. Our proposed controller exhibits much less steady state error, quick error convergence in the presence of disturbance or noise, and model uncertainties.

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.......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...

Orbit Determination from Tracking Data of Artificial Satellite Using the Method of Differential Correction

OpenAIRE

Byoung-Sun Lee; Jung-Hyun Jo; Sang-Young Park; Kyu-Hong Choi; Chun-Hwey Kim

1988-01-01

The differential correction process determining osculating orbital elements as correct as possible at a given instant of time from tracking data of artificial satellite was accomplished. Preliminary orbital elements were used as an initial value of the differential correction procedure and iterated until the residual of real observation(O) and computed observation(C) was minimized. Tracking satellite was NOAA-9 or TIROS-N series. Two types of tracking data were prediction data precomputed fro...

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 machine...

Tracking Small Satellites using Translated GPS

OpenAIRE

Lefevre, Don; Mulally, Daniel

1991-01-01

This paper discusses using translated GPS for tracking small satellites, the technical trade-offs involved, and the position and timing accuracies which are achievable using translated GPS. The Global Positioning System (GPS) uses the relative times-of-arrival of multiple spread-spectrum signals at an antenna to determine the position of the antenna. The system can also determine the time the antenna was at that position. The direct sequence spread spectrum signals are transmitted from GPS sa...

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...

Tracking Object Existence From an Autonomous Patrol Vehicle

Science.gov (United States)

Wolf, Michael; Scharenbroich, Lucas

2011-01-01

uncertainty arising from errors in sensors and upstream processes. However, traditional target tracking methods typically assume a stationary detection volume of interest, whereas in this case, one must make adjustments for being able to see only a small portion of the region of interest and understand when an alert situation has occurred. To track object existence inside and outside the vehicle's sensor range, a probability of existence was defined for each hypothesized object, and this value was updated at every time step in a Bayesian manner based on expected characteristics of the sensor and object and whether that object has been detected in the most recent time step. Then, this value feeds into a sequential probability ratio test (SPRT) to determine the status of the object (suspected, confirmed, or deleted). Alerts are sent upon selected status transitions. Additionally, in order to track objects that move in and out of sensor range and update the probability of existence appropriately a variable probability detection has been defined and the hypothesis probability equations have been re-derived to accommodate this change. Unsupervised object tracking is a pervasive issue in automated perception systems. This work could apply to any mobile platform (ground vehicle, sea vessel, air vehicle, or orbiter) that intermittently revisits regions of interest and needs to determine whether anything interesting has changed.

A Fuzzy Rule-based Controller For Automotive Vehicle Guidance

OpenAIRE

Hessburg, Thomas; Tomizuka, Masayoshi

1991-01-01

A fuzzy rule-based controller is applied to lateral guidance of a vehicle for an automated highway system. The fuzzy rules, based on human drivers' experiences, are developed to track the center of a lane in the presence of external disturbances and over a range of vehicle operating conditions.

Visual tracking strategies for intelligent vehicle highway systems

Science.gov (United States)

Smith, Christopher E.; Papanikolopoulos, Nikolaos P.; Brandt, Scott A.; Richards, Charles

1995-01-01

The complexity and congestion of current transportation systems often produce traffic situations that jeopardize the safety of the people involved. These situations vary from maintaining a safe distance behind a leading vehicle to safely allowing a pedestrian to cross a busy street. Environmental sensing plays a critical role in virtually all of these situations. Of the sensors available, vision sensors provide information that is richer and more complete than other sensors, making them a logical choice for a multisensor transportation system. In this paper we present robust techniques for intelligent vehicle-highway applications where computer vision plays a crucial role. In particular, we demonstrate that the controlled active vision framework can be utilized to provide a visual sensing modality to a traffic advisory system in order to increase the overall safety margin in a variety of common traffic situations. We have selected two application examples, vehicle tracking and pedestrian tracking, to demonstrate that the framework can provide precisely the type of information required to effectively manage the given situation.

Robust FDI for A Ship-mounted Satellite Tracking Antenna: A Nonlinear Approach

DEFF Research Database (Denmark)

Soltani, Mohsen; Izadi-Zamanabadi, Roozbeh; Wisniewski, Rafal

2008-01-01

Overseas telecommunication is preserved by means of satellite communication. Tracking system postures the on-board antenna toward a chosen satellite while the external disturbances affect the antenna. Certain faults (beam sensor malfunction or signal blocking) cause interruption in the communicat...

Satellite tracking of manta rays highlights challenges to their conservation.

Directory of Open Access Journals (Sweden)

Rachel T Graham

Full Text Available We describe the real-time movements of the last of the marine mega-vertebrate taxa to be satellite tracked - the giant manta ray (or devil fish, Manta birostris, the world's largest ray at over 6 m disc width. Almost nothing is known about manta ray movements and their environmental preferences, making them one of the least understood of the marine mega-vertebrates. Red listed by the International Union for the Conservation of Nature as 'Vulnerable' to extinction, manta rays are known to be subject to direct and incidental capture and some populations are declining. Satellite-tracked manta rays associated with seasonal upwelling events and thermal fronts off the Yucatan peninsula, Mexico, and made short-range shuttling movements, foraging along and between them. The majority of locations were received from waters shallower than 50 m deep, representing thermally dynamic and productive waters. Manta rays remained in the Mexican Exclusive Economic Zone for the duration of tracking but only 12% of tracking locations were received from within Marine Protected Areas (MPAs. Our results on the spatio-temporal distribution of these enigmatic rays highlight opportunities and challenges to management efforts.

Satellite tracking of manta rays highlights challenges to their conservation.

Science.gov (United States)

Graham, Rachel T; Witt, Matthew J; Castellanos, Dan W; Remolina, Francisco; Maxwell, Sara; Godley, Brendan J; Hawkes, Lucy A

2012-01-01

We describe the real-time movements of the last of the marine mega-vertebrate taxa to be satellite tracked - the giant manta ray (or devil fish, Manta birostris), the world's largest ray at over 6 m disc width. Almost nothing is known about manta ray movements and their environmental preferences, making them one of the least understood of the marine mega-vertebrates. Red listed by the International Union for the Conservation of Nature as 'Vulnerable' to extinction, manta rays are known to be subject to direct and incidental capture and some populations are declining. Satellite-tracked manta rays associated with seasonal upwelling events and thermal fronts off the Yucatan peninsula, Mexico, and made short-range shuttling movements, foraging along and between them. The majority of locations were received from waters shallower than 50 m deep, representing thermally dynamic and productive waters. Manta rays remained in the Mexican Exclusive Economic Zone for the duration of tracking but only 12% of tracking locations were received from within Marine Protected Areas (MPAs). Our results on the spatio-temporal distribution of these enigmatic rays highlight opportunities and challenges to management efforts.

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

A Path Tracking Algorithm Using Future Prediction Control with Spike Detection for an Autonomous Vehicle Robot

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Muhammad Aizzat Zakaria

2013-08-01

Full Text Available Trajectory tracking is an important aspect of autonomous vehicles. The idea behind trajectory tracking is the ability of the vehicle to follow a predefined path with zero steady state error. The difficulty arises due to the nonlinearity of vehicle dynamics. Therefore, this paper proposes a stable tracking control for an autonomous vehicle. An approach that consists of steering wheel control and lateral control is introduced. This control algorithm is used for a non-holonomic navigation problem, namely tracking a reference trajectory in a closed loop form. A proposed future prediction point control algorithm is used to calculate the vehicle's lateral error in order to improve the performance of the trajectory tracking. A feedback sensor signal from the steering wheel angle and yaw rate sensor is used as feedback information for the controller. The controller consists of a relationship between the future point lateral error, the linear velocity, the heading error and the reference yaw rate. This paper also introduces a spike detection algorithm to track the spike error that occurs during GPS reading. The proposed idea is to take the advantage of the derivative of the steering rate. This paper aims to tackle the lateral error problem by applying the steering control law to the vehicle, and proposes a new path tracking control method by considering the future coordinate of the vehicle and the future estimated lateral error. The effectiveness of the proposed controller is demonstrated by a simulation and a GPS experiment with noisy data. The approach used in this paper is not limited to autonomous vehicles alone since the concept of autonomous vehicle tracking can be used in mobile robot platforms, as the kinematic model of these two platforms is similar.

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 equipment...

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.

First satellite tracks of neonate sea turtles redefine the ‘lost years’ oceanic niche

Science.gov (United States)

Mansfield, Katherine L.; Wyneken, Jeanette; Porter, Warren P.; Luo, Jiangang

2014-01-01

Few at-sea behavioural data exist for oceanic-stage neonate sea turtles, a life-stage commonly referred to as the sea turtle ‘lost years’. Historically, the long-term tracking of small, fast-growing organisms in the open ocean was logistically or technologically impossible. Here, we provide the first long-term satellite tracks of neonate sea turtles. Loggerheads (Caretta caretta) were remotely tracked in the Atlantic Ocean using small solar-powered satellite transmitters. We show that oceanic-stage turtles (i) rarely travel in Continental Shelf waters, (ii) frequently depart the currents associated with the North Atlantic Subtropical Gyre, (iii) travel quickly when in Gyre currents, and (iv) select sea surface habitats that are likely to provide a thermal benefit or refuge to young sea turtles, supporting growth, foraging and survival. Our satellite tracks help define Atlantic loggerhead nursery grounds and early loggerhead habitat use, allowing us to re-examine sea turtle ‘lost years’ paradigms. PMID:24598420

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

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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.

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

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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.

Experiments in teleoperator and autonomous control of space robotic vehicles

Science.gov (United States)

Alexander, Harold L.

1991-01-01

A program of research embracing teleoperator and automatic navigational control of freely flying satellite robots is presented. Current research goals include: (1) developing visual operator interfaces for improved vehicle teleoperation; (2) determining the effects of different visual interface system designs on operator performance; and (3) achieving autonomous vision-based vehicle navigation and control. This research program combines virtual-environment teleoperation studies and neutral-buoyancy experiments using a space-robot simulator vehicle currently under development. Visual-interface design options under investigation include monoscopic versus stereoscopic displays and cameras, helmet-mounted versus panel-mounted display monitors, head-tracking versus fixed or manually steerable remote cameras, and the provision of vehicle-fixed visual cues, or markers, in the remote scene for improved sensing of vehicle position, orientation, and motion.

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.

Orbit Determination from Tracking Data of Artificial Satellite Using the Method of Differential Correction

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Byoung-Sun Lee

1988-06-01

Full Text Available The differential correction process determining osculating orbital elements as correct as possible at a given instant of time from tracking data of artificial satellite was accomplished. Preliminary orbital elements were used as an initial value of the differential correction procedure and iterated until the residual of real observation(O and computed observation(C was minimized. Tracking satellite was NOAA-9 or TIROS-N series. Two types of tracking data were prediction data precomputed from mean orbital elements of TBUS and real data obtained from tracking 1.707GHz HRPT signal of NOAA-9 using 5 meter auto-track antenna in Radio Research Laboratory. According to tracking data either Gauss method or Herrick-Gibbs method was applied to preliminary orbit determination. In the differential correction stage we used both of the Escobal(1975's analytical method and numerical ones are nearly consistent. And the differentially corrected orbit converged to the same value in spite of the differences between preliminary orbits of each time span.

PEMODELAN DISTRIBUSI KESESUAIAN HABITAT SINGGAH SIKEP MADU ASIA (Pernis ptilorhynchus DI PULAU RUPAT BERDASARKAN DATA SATELLITE- TRACKING

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Hendry Pramono

2016-01-01

Full Text Available Birds of prey are one of environmental changes indicators because of their position as top predator. Many of them are migratory species that migrate from northern hemisphere to southern hemisphere, and use Rupat Island (in Riau Province as stopover habitat. One of them is Oriental Honey Buzzard (Pernis ptilorhynchus whose satellite tracking information (from 2006-2009 are available. This study aimed at identifying distribution characteristics of stopover habitats of Oriental Honey-buzzard in Rupat Island based on satellite tracking data using geographic information system (GIS. Several environmental variables (i.e. slope, elevation, land cover were processed into distance to the nearest map and analyzed using logistic regression analysis. The result showed that distribution of stopover habitats covered 1 276.67 km2 (87% of totally Rupat Island (1 461.95 km2. This distribution was mostly influenced by food availability and thermal wind. Identification of these habitat characteristics provides a baseline data for managing their stopover habitats and ecologically-based development of Rupat Island. Keywords: Logistic Regretion, Pernis ptilorhynchus, Rupat Island, Sattelite-tracking, Stopover habitat characteristic

A Study on the Tracking and Position Predictions of Artificial Satellite (II

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Pil-Ho Park

1991-06-01

Full Text Available We developed a software system called IODS (ISSA Orbit Determination System, which can predict the orbit of arbitrary artificial satellite using the numerical method. For evaluating the orbit prediction accuracy of IODS, the orbital data predicted for the meteorological satellite NOAA-11 and the stationary satellite INTELSAT-V are intercompared with those tracked at the Central Bureau of Meteorology and the Kum-San Satellites Communication Station. And the Perturbation affecting the orbit of these artificial satellites are quantitatively analyzed. The orbital variation and the eclipse phenomina due to the earth shadow are analyzed for a hypothetical geostationary satellite called KORSAT-1 which is assumed to be located in longitude 110°E.

A Small Ku-Band Polarization Tracking Active Phased Array for Mobile Satellite Communications

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Wei Shi

2013-01-01

Full Text Available A compact polarization tracking active phased array for Ku-band mobile satellite signal reception is presented. In contrast with conventional mechanically tracking antennas, the approach presented here meets the requirements of beam tracking and polarization tracking simultaneously without any servo components. The two-layer stacked square patch fed by two probes is used as antenna element. The impedance bandwidth of 16% for the element covers the operating frequency range from 12.25 GHz to 12.75 GHz. In the presence of mutual coupling, the dimensional parameters for each element of the small 7 × 7 array are optimized during beam scanning and polarization tracking. The compact polarization tracking modules based on the low-temperature cofired ceramic (LTCC system-in-package (SiP technology are proposed. A small active phased array prototype with the size of 120 mm (length × 120 mm (width × 55 mm (height is developed. The measured polarization tracking patterns of the prototype are given. The polarization tracking beam can be steered in the elevation up to 50°. The gain of no less than 16.0 dBi and the aperture efficiency of more than 50% are obtained. The measured and simulated polarization tracking patterns agreed well.

Impacts of tracked vehicles on sediment from a desert soil

Science.gov (United States)

Erek H. Fuchs; Karl M. Wood; Tim L. Jones; Brent Racher

2003-01-01

Off-road military vehicle traffic is a major consideration in the management of military lands. The objective of this study was to determine the impacts of military tracked M1A1 heavy combat tank vehicles on sediment loss from runoff, surface plant cover, and surface microtopography in a desert military training environment. A randomized block design was used which had...

Remote Sensing-based Models of Soil Vulnerability to Compaction and Erosion from Off-highway Vehicles

Science.gov (United States)

Villarreal, M. L.; Webb, R. H.; Norman, L.; Psillas, J.; Rosenberg, A.; Carmichael, S.; Petrakis, R.; Sparks, P.

2014-12-01

Intensive off-road vehicle use for immigration, smuggling, and security of the United States-Mexico border has prompted concerns about long-term human impacts on sensitive desert ecosystems. To help managers identify areas susceptible to soil erosion from vehicle disturbances, we developed a series of erosion potential models based on factors from the Revised Universal Soil Loss Equation (RUSLE), with particular focus on the management factor (P-factor) and vegetation cover (C-factor). To better express the vulnerability of soils to human disturbances, a soil compaction index (applied as the P-factor) was calculated as the difference in saturated hydrologic conductivity (Ks) between disturbed and undisturbed soils, which was then scaled up to remote sensing-based maps of vehicle tracks and digital soils maps. 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 regional land cover maps (r2 = 0.06). RUSLE factors were normalized to give equal weight to all contributing factors, which provided more management-specific information on vulnerable areas where vehicle compaction of sensitive soils intersects with steep slopes and low vegetation cover. Resulting spatial data on vulnerability and erosion potential provide land managers with information to identify critically disturbed areas and potential restoration sites where off-road driving should be restricted to reduce further degradation.

PaTAVTT: A Hardware-in-the-Loop Scaled Platform for Testing Autonomous Vehicle Trajectory Tracking

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Zhigang Xu

2017-01-01

Full Text Available With the advent of autonomous vehicles, in particular its adaptability to harsh conditions, the research and development of autonomous vehicles attract significant attention by not only academia but also practitioners. Due to the high risk, high cost, and difficulty to test autonomous vehicles under harsh conditions, the hardware-in-the-loop (HIL scaled platform has been proposed as it is a safe, inexpensive, and effective test method. This platform system consists of scaled autonomous vehicle, scaled roadway, monitoring center, transmission device, positioning device, and computers. This paper uses a case of the development process of tracking control for high-speed U-turn to build the tracking control function. Further, a simplified vehicle dynamics model and a trajectory tracking algorithm have been considered to build the simulation test. The experiment results demonstrate the effectiveness of the HIL scaled platform.

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.

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

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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.

Straight-Line Target Tracking for Unmanned Surface Vehicles

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Morten Breivik

2008-10-01

Full Text Available This paper considers the subject of straight-line target tracking for unmanned surface vehicles (USVs. Target-tracking represents motion control scenarios where no information about the target behavior is known in advance, i.e., the path that the target traverses is not defined apriori. Specifically, this work presents the design of a motion control system which enables an underactuated USV to track a target that moves in a straight line at high speed. The motion control system employs a guidance principle originally developed for interceptor missiles, as well as a novel velocity controller inspired by maneuverability and agility concepts found in fighter aircraft literature. The performance of the suggested design is illustrated through full-scale USV experiments in the Trondheimsfjord.

Satellite tracking of radioactive shipments - High technology solution to tough institutional problems

International Nuclear Information System (INIS)

Harmon, L.H.; Grimm, P.D.

1987-01-01

Three troublesome institutional issues face every large-quantity radioactive materials shipment. They are routing, pre-notification, and emergency response. The Transportation Communications System (TRANSCOM), under development by DOE, is based on a rapidly developing technology to determine geographical location using geo-positioning satellite systems. This technology will be used to track unclassified radioactive materials shipments in real-time. It puts those charged with monitoring transportation status on top of very shipment. Besides its practical benefits in the areas of logistics planning and execution, it demonstrates emergency preparedness has indeed been considered and close monitoring is possible. This paper describes TRANSCOM in its technical detail and DOE plans and policy for its implementation. The state of satellite positioning technology and its business future is also discussed

Optimal Design of a Novel Hybrid Electric Powertrain for Tracked Vehicles

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Zhaobo Qin

2017-12-01

Full Text Available Tracked vehicles have been widely used in construction, agriculture, and the military. Major problems facing the industry, however, are high emissions and fuel consumption. Hybrid electric tracked vehicles have thus become increasingly popular because of their improved fuel economy and reduced emissions. While the series hybrid system has drawn the most attention and has been applied in most cases, the low efficiency caused by energy conversion losses and large propulsion motors has limited its development. A novel multi-mode powertrain with two output shafts controlling each side of the track independently is first proposed. The powertrain is a three-planetary-gear power-split system with one engine, three motors, and an ultracapacitor pack. Compared with the existing technologies, the proposed powertrain can realize skid steering without an extra steering mechanism, and significantly improve the overall efficiency. To demonstrate the advantages of the novel powertrain, a topology-control-size integrated optimization problem is solved based on drivability, fuel economy, and cost. Final simulation results show that the optimized design with downsized components can produce about a 30% improvement in drivability and a 15% improvement in fuel economy compared with the commonly used series hybrid benchmark. Moreover, the optimized design is verified to be much more economical taking cumulative cost into account, which is very attractive for potential industrial applications in the future.

Part-based Pedestrian Detection and Feature-based Tracking for Driver Assistance

DEFF Research Database (Denmark)

Prioletti, Antonio; Møgelmose, Andreas; Grislieri, Paolo

2013-01-01

Detecting pedestrians is still a challenging task for automotive vision systems due to the extreme variability of targets, lighting conditions, occlusion, and high-speed vehicle motion. Much research has been focused on this problem in the last ten years and detectors based on classifiers have...... on a prototype vehicle and offers high performance in terms of several metrics, such as detection rate, false positives per hour, and frame rate. The novelty of this system relies on the combination of a HOG part-based approach, tracking based on a specific optimized feature, and porting on a real prototype....

Migratory herbivorous waterfowl track satellite-derived green wave index.

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Mitra Shariatinajafabadi

Full Text Available Many migrating herbivores rely on plant biomass to fuel their life cycles and have adapted to following changes in plant quality through time. The green wave hypothesis predicts that herbivorous waterfowl will follow the wave of food availability and quality during their spring migration. However, testing this hypothesis is hampered by the large geographical range these birds cover. The satellite-derived normalized difference vegetation index (NDVI time series is an ideal proxy indicator for the development of plant biomass and quality across a broad spatial area. A derived index, the green wave index (GWI, has been successfully used to link altitudinal and latitudinal migration of mammals to spatio-temporal variations in food quality and quantity. To date, this index has not been used to test the green wave hypothesis for individual avian herbivores. Here, we use the satellite-derived GWI to examine the green wave hypothesis with respect to GPS-tracked individual barnacle geese from three flyway populations (Russian n = 12, Svalbard n = 8, and Greenland n = 7. Data were collected over three years (2008-2010. Our results showed that the Russian and Svalbard barnacle geese followed the middle stage of the green wave (GWI 40-60%, while the Greenland geese followed an earlier stage (GWI 20-40%. Despite these differences among geese populations, the phase of vegetation greenness encountered by the GPS-tracked geese was close to the 50% GWI (i.e. the assumed date of peak nitrogen concentration, thereby implying that barnacle geese track high quality food during their spring migration. To our knowledge, this is the first time that the migration of individual avian herbivores has been successfully studied with respect to vegetation phenology using the satellite-derived GWI. Our results offer further support for the green wave hypothesis applying to long-distance migrants on a larger scale.

An Attitude Heading and Reference System For Marine Satellite Tracking Antenna

DEFF Research Database (Denmark)

Wang, Yunlong; Soltani, Mohsen; Hussain, Dil muhammed Akbar

2017-01-01

One of the most challenging problems for marine satellite tracking antennas (MSTAs) is to estimate the antenna attitude, which is affected by the ship motion, especially the ship vibration and rotational motions caused by ocean waves. To overcome this problem, an attitude heading and reference...... conditions, an attitude estimator based on virtual horizontal reference is introduced for situations of accelerometer malfunction, where the ship is suffering from wave shocks in high sea states. The performance of the designed AHRS for MSTA is assessed through hardware experiments using a Stewart platform...

Species distribution models for a migratory bird based on citizen science and satellite tracking data

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Christopher L. Coxen

2017-07-01

Full Text Available Species distribution models can provide critical baseline distribution information for the conservation of poorly understood species. Here, we compared the performance of band-tailed pigeon (Patagioenas fasciata species distribution models created using Maxent and derived from two separate presence-only occurrence data sources in New Mexico: 1 satellite tracked birds and 2 observations reported in eBird basic data set. Both models had good accuracy (test AUC > 0.8 and True Skill Statistic > 0.4, and high overlap between suitability scores (I statistic 0.786 and suitable habitat patches (relative rank 0.639. Our results suggest that, at the state-wide level, eBird occurrence data can effectively model similar species distributions as satellite tracking data. Climate change models for the band-tailed pigeon predict a 35% loss in area of suitable climate by 2070 if CO2 emissions drop to 1990 levels by 2100, and a 45% loss by 2070 if we continue current CO2 emission levels through the end of the century. These numbers may be conservative given the predicted increase in drought, wildfire, and forest pest impacts to the coniferous forests the species inhabits in New Mexico. The northern portion of the species’ range in New Mexico is predicted to be the most viable through time.

Species distribution models for a migratory bird based on citizen science and satellite tracking data

Science.gov (United States)

Coxen, Christopher L.; Frey, Jennifer K.; Carleton, Scott A.; Collins, Daniel P.

2017-01-01

Species distribution models can provide critical baseline distribution information for the conservation of poorly understood species. Here, we compared the performance of band-tailed pigeon (Patagioenas fasciata) species distribution models created using Maxent and derived from two separate presence-only occurrence data sources in New Mexico: 1) satellite tracked birds and 2) observations reported in eBird basic data set. Both models had good accuracy (test AUC > 0.8 and True Skill Statistic > 0.4), and high overlap between suitability scores (I statistic 0.786) and suitable habitat patches (relative rank 0.639). Our results suggest that, at the state-wide level, eBird occurrence data can effectively model similar species distributions as satellite tracking data. Climate change models for the band-tailed pigeon predict a 35% loss in area of suitable climate by 2070 if CO2 emissions drop to 1990 levels by 2100, and a 45% loss by 2070 if we continue current CO2 emission levels through the end of the century. These numbers may be conservative given the predicted increase in drought, wildfire, and forest pest impacts to the coniferous forests the species inhabits in New Mexico. The northern portion of the species’ range in New Mexico is predicted to be the most viable through time.

Target tracking control and semi-physical simulation of Qball-X4 quad-rotor unmanned aerial vehicle

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Lu Liu

2017-01-01

Full Text Available In this article, a set of integrated ground target tracking flight system has been proposed based on the Qball-X4 quad-rotor unmanned aerial vehicle hardware platform and the QuaRC software platform. Both of the hardware and software platforms are developed by Quanser Company, Canada. The proposed tracking and positioning algorithm could be divided into several stages. First, a tracker is developed based on an optical flow method to track the target; and then, in order to improve the reliability of tracking algorithm and also help in retrieving the lost target, a cascade target detector is developed; meanwhile, a model updated scheme aiming at some possible errors in tracking and detecting process is presented based on Positive-Negative (P-N learning system; at last, a monocular visual positioning system is designed based on the corresponding navigation message. In addition, the effectiveness of the proposed flight control system is verified by both simulation and hardware-in-loop system results in several tracking flight tests.

Measurement-based perturbation theory and differential equation parameter estimation with applications to satellite gravimetry

Science.gov (United States)

Xu, Peiliang

2018-06-01

The numerical integration method has been routinely used by major institutions worldwide, for example, NASA Goddard Space Flight Center and German Research Center for Geosciences (GFZ), to produce global gravitational models from satellite tracking measurements of CHAMP and/or GRACE types. Such Earth's gravitational products have found widest possible multidisciplinary applications in Earth Sciences. The method is essentially implemented by solving the differential equations of the partial derivatives of the orbit of a satellite with respect to the unknown harmonic coefficients under the conditions of zero initial values. From the mathematical and statistical point of view, satellite gravimetry from satellite tracking is essentially the problem of estimating unknown parameters in the Newton's nonlinear differential equations from satellite tracking measurements. We prove that zero initial values for the partial derivatives are incorrect mathematically and not permitted physically. The numerical integration method, as currently implemented and used in mathematics and statistics, chemistry and physics, and satellite gravimetry, is groundless, mathematically and physically. Given the Newton's nonlinear governing differential equations of satellite motion with unknown equation parameters and unknown initial conditions, we develop three methods to derive new local solutions around a nominal reference orbit, which are linked to measurements to estimate the unknown corrections to approximate values of the unknown parameters and the unknown initial conditions. Bearing in mind that satellite orbits can now be tracked almost continuously at unprecedented accuracy, we propose the measurement-based perturbation theory and derive global uniformly convergent solutions to the Newton's nonlinear governing differential equations of satellite motion for the next generation of global gravitational models. Since the solutions are global uniformly convergent, theoretically speaking

Virtual target tracking (VTT) as applied to mobile satellite communication networks

Science.gov (United States)

Amoozegar, Farid

1999-08-01

Traditionally, target tracking has been used for aerospace applications, such as, tracking highly maneuvering targets in a cluttered environment for missile-to-target intercept scenarios. Although the speed and maneuvering capability of current aerospace targets demand more efficient algorithms, many complex techniques have already been proposed in the literature, which primarily cover the defense applications of tracking methods. On the other hand, the rapid growth of Global Communication Systems, Global Information Systems (GIS), and Global Positioning Systems (GPS) is creating new and more diverse challenges for multi-target tracking applications. Mobile communication and computing can very well appreciate a huge market for Cellular Communication and Tracking Devices (CCTD), which will be tracking networked devices at the cellular level. The objective of this paper is to introduce a new concept, i.e., Virtual Target Tracking (VTT) for commercial applications of multi-target tracking algorithms and techniques as applied to mobile satellite communication networks. It would be discussed how Virtual Target Tracking would bring more diversity to target tracking research.

High Dynamic Optimized Carrier Loop Improvement for Tracking Doppler Rates

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Amirhossein Fereidountabar

2015-01-01

Full Text Available Mathematical analysis and optimization of a carrier tracking loop are presented. Due to fast changing of the carrier frequency in some satellite systems, such as Low Earth Orbit (LEO or Global Positioning System (GPS, or some planes like Unmanned Aerial Vehicles (UAVs, high dynamic tracking loops play a very important role. In this paper an optimized tracking loop consisting of a third-order Phase Locked Loop (PLL assisted by a second-order Frequency Locked Loop (FLL for UAVs is proposed and discussed. Based on this structure an optimal loop has been designed. The main advantages of this approach are the reduction of the computation complexity and smaller phase error. The paper shows the simulation results, comparing them with a previous work.

AUV-Based Plume Tracking: A Simulation Study

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Awantha Jayasiri

2016-01-01

Full Text Available This paper presents a simulation study of an autonomous underwater vehicle (AUV navigation system operating in a GPS-denied environment. The AUV navigation method makes use of underwater transponder positioning and requires only one transponder. A multirate unscented Kalman filter is used to determine the AUV orientation and position by fusing high-rate sensor data and low-rate information. The paper also proposes a gradient-based, efficient, and adaptive novel algorithm for plume boundary tracking missions. The algorithm follows a centralized approach and it includes path optimization features based on gradient information. The proposed algorithm is implemented in simulation on the AUV-based navigation system and successful boundary tracking results are obtained.

Network design consideration of a satellite-based mobile communications system

Science.gov (United States)

Yan, T.-Y.

1986-01-01

Technical considerations for the Mobile Satellite Experiment (MSAT-X), the ground segment testbed for the low-cost spectral efficient satellite-based mobile communications technologies being developed for the 1990's, are discussed. The Network Management Center contains a flexible resource sharing algorithm, the Demand Assigned Multiple Access scheme, which partitions the satellite transponder bandwidth among voice, data, and request channels. Satellite use of multiple UHF beams permits frequency reuse. The backhaul communications and the Telemetry, Tracking and Control traffic are provided through a single full-coverage SHF beam. Mobile Terminals communicate with the satellite using UHF. All communications including SHF-SHF between Base Stations and/or Gateways, are routed through the satellite. Because MSAT-X is an experimental network, higher level network protocols (which are service-specific) will be developed only to test the operation of the lowest three levels, the physical, data link, and network layers.

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.

Launch Vehicles Based on Advanced Hybrid Rocket Motors: An Enabling Technology for the Commercial Small and Micro Satellite Planetary Science

Science.gov (United States)

Karabeyoglu, Arif; Tuncer, Onur; Inalhan, Gokhan

2016-07-01

Mankind is relient on chemical propulsion systems for space access. Nevertheless, this has been a stagnant area in terms of technological development and the technology base has not changed much almost for the past forty years. This poses a vicious circle for launch applications such that high launch costs constrain the demand and low launch freqencies drive costs higher. This also has been a key limiting factor for small and micro satellites that are geared towards planetary science. Rather this be because of the launch frequencies or the costs, the access of small and micro satellites to orbit has been limited. With today's technology it is not possible to escape this circle. However the emergence of cost effective and high performance propulsion systems such as advanced hybrid rockets can decrease launch costs by almost an order or magnitude. This paper briefly introduces the timeline and research challenges that were overcome during the development of advanced hybrid LOX/paraffin based rockets. Experimental studies demonstrated effectiveness of these advanced hybrid rockets which incorporate fast burning parafin based fuels, advanced yet simple internal balistic design and carbon composite winding/fuel casting technology that enables the rocket motor to be built from inside out. A feasibility scenario is studied using these rocket motors as building blocks for a modular launch vehicle capable of delivering micro satellites into low earth orbit. In addition, the building block rocket motor can be used further solar system missions providing the ability to do standalone small and micro satellite missions to planets within the solar system. This enabling technology therefore offers a viable alternative in order to escape the viscous that has plagued the space launch industry and that has limited the small and micro satellite delivery for planetary science.

Advanced Emergency Braking Control Based on a Nonlinear Model Predictive Algorithm for Intelligent Vehicles

Directory of Open Access Journals (Sweden)

Ronghui Zhang

2017-05-01

Full Text Available Focusing on safety, comfort and with an overall aim of the comprehensive improvement of a vision-based intelligent vehicle, a novel Advanced Emergency Braking System (AEBS is proposed based on Nonlinear Model Predictive Algorithm. Considering the nonlinearities of vehicle dynamics, a vision-based longitudinal vehicle dynamics model is established. On account of the nonlinear coupling characteristics of the driver, surroundings, and vehicle itself, a hierarchical control structure is proposed to decouple and coordinate the system. To avoid or reduce the collision risk between the intelligent vehicle and collision objects, a coordinated cost function of tracking safety, comfort, and fuel economy is formulated. Based on the terminal constraints of stable tracking, a multi-objective optimization controller is proposed using the theory of non-linear model predictive control. To quickly and precisely track control target in a finite time, an electronic brake controller for AEBS is designed based on the Nonsingular Fast Terminal Sliding Mode (NFTSM control theory. To validate the performance and advantages of the proposed algorithm, simulations are implemented. According to the simulation results, the proposed algorithm has better integrated performance in reducing the collision risk and improving the driving comfort and fuel economy of the smart car compared with the existing single AEBS.

Evolution of NASA's Near-Earth Tracking and Data Relay Satellite System (TDRSS)

Science.gov (United States)

Flaherty, Roger; Stocklin, Frank; Weinberg, Aaron

2006-01-01

NASA's Tracking and Data Relay Satellite System (TDRSS) is now in its 23rd year of operations and its spacecraft fleet includes three second-generation spacecraft launched since the year 2000; a figure illustrates the first generation TDRSS spacecraft. During this time frame the TDRSS has provided communications relay support to a broad range of missions, with emphasis on low-earth-orbiting (LEO) spacecraft that include unmanned science spacecraft (e.g., Hubble Space Telescope), and human spaceflight (Space Shuttle and Space Station). Furthermore, the TDRSS has consistently demonstrated its uniqueness and adaptability in several ways. First, its S- and K-band services, combined with its multi-band/steerable single-access (SA) antennas and ground-based configuration flexibility, have permitted the mission set to expand to unique users such as scientific balloons and launch vehicles. Second, the bent-pipe nature of the system has enabled the introduction of new/improved services via technology insertion and upgrades at each of the ground terminals; a specific example here is the Demand Access Service (DAS), which, for example, is currently providing science-alert support to NASA science missions Third, the bent-pipe nature of the system, combined with the flexible ground-terminal signal processing architecture has permitted the demonstration/vaIidation of new techniques/services/technologies via a real satellite channel; over the past 10+ years these have, for example, included demonstrations/evaluations of emerging modulation/coding techniques. Given NASA's emerging Exploration plans, with missions beginning later this decade and expanding for decades to come, NASA is currently planning the development of a seamless, NASA-wide architecture that must accommodate missions from near-earth to deep space. Near-earth elements include Ground-Network (GN) and Near-Earth Relay (NER) components and both must efficiently and seamlessly support missions that encompass: earth

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.

Target Detection Based on EBPSK Satellite Passive Radar

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Lu Zeyuan

2015-05-01

Full Text Available Passive radar is a topic anti stealth technology with simple structure, and low cost. Radiation source model, signal transmission model, and target detection are the key points of passive radar technology research. The paper analyzes the characteristics of EBPSK signal modulation and target detection method aspect of spaceborne radiant source. By comparison with other satellite navigation and positioning system, the characteristics of EBPSK satellite passive radar system are analyzed. It is proved that the maximum detection range of EBPSK satellite signal can satisfy the needs of the proposed model. In the passive radar model, sparse representation is used to achieve high resolution DOA detection. The comparison with the real target track by simulation demonstrates that effective detection of airborne target using EBPSK satellite passive radar system based on sparse representation is efficient.

Cooperative vehicle control, feature tracking and ocean sampling

Science.gov (United States)

Fiorelli, Edward A.

This dissertation concerns the development of a feedback control framework for coordinating multiple, sensor-equipped, autonomous vehicles into mobile sensing arrays to perform adaptive sampling of observed fields. The use of feedback is central; it maintains the array, i.e. regulates formation position, orientation, and shape, and directs the array to perform its sampling mission in response to measurements taken by each vehicle. Specifically, we address how to perform autonomous gradient tracking and feature detection in an unknown field such as temperature or salinity in the ocean. Artificial potentials and virtual bodies are used to coordinate the autonomous vehicles, modelled as point masses (with unit mass). The virtual bodies consist of linked, moving reference points called virtual leaders. Artificial potentials couple the dynamics of the vehicles and the virtual bodies. The dynamics of the virtual body are then prescribed allowing the virtual body, and thus the vehicle group, to perform maneuvers that include translation, rotation and contraction/expansion, while ensuring that the formation error remains bounded. This methodology is called the Virtual Body and Artificial Potential (VBAP) methodology. We then propose how to utilize these arrays to perform autonomous gradient climbing and front tracking in the presence of both correlated and uncorrelated noise. We implement various techniques for estimation of gradients (first-order and higher), including finite differencing, least squares error minimization, averaging, and Kalman filtering. Furthermore, we illustrate how the estimation error can be used to optimally choose the formation size. To complement our theoretical work, we present an account of sea trials performed with a fleet of autonomous underwater gliders in Monterey Bay during the Autonomous Ocean Sampling Network (AOSN) II project in August 2003. During these trials, Slocum autonomous underwater gliders were coordinated into triangle

Technique applied in electrical power distribution for Satellite Launch Vehicle

Directory of Open Access Journals (Sweden)

João Maurício Rosário

2010-09-01

Full Text Available The Satellite Launch Vehicle electrical network, which is currently being developed in Brazil, is sub-divided for analysis in the following parts: Service Electrical Network, Controlling Electrical Network, Safety Electrical Network and Telemetry Electrical Network. During the pre-launching and launching phases, these electrical networks are associated electrically and mechanically to the structure of the vehicle. In order to succeed in the integration of these electrical networks it is necessary to employ techniques of electrical power distribution, which are proper to Launch Vehicle systems. This work presents the most important techniques to be considered in the characterization of the electrical power supply applied to Launch Vehicle systems. Such techniques are primarily designed to allow the electrical networks, when submitted to the single-phase fault to ground, to be able of keeping the power supply to the loads.

GSFC network operations with Tracking and Data Relay Satellites

Science.gov (United States)

Spearing, R.; Perreten, D. E.

The Tracking and Data Relay Satellite System (TDRSS) Network (TN) has been developed to provide services to all NASA User spacecraft in near-earth orbits. Three inter-relating entities will provide these services. The TN has been transformed from a network continuously changing to meet User specific requirements to a network which is flexible to meet future needs without significant changes in operational concepts. Attention is given to the evolution of the TN network, the TN capabilities-space segment, forward link services, tracking services, return link services, the three basic capabilities, single access services, multiple access services, simulation services, the White Sands Ground Terminal, the NASA communications network, and the network control center.

A GPS measurement system for precise satellite tracking and geodesy

Science.gov (United States)

Yunck, T. P.; Wu, S.-C.; Lichten, S. M.

1985-01-01

NASA is pursuing two key applications of differential positioning with the Global Positioning System (GPS): sub-decimeter tracking of earth satellites and few-centimeter determination of ground-fixed baselines. Key requirements of the two applications include the use of dual-frequency carrier phase data, multiple ground receivers to serve as reference points, simultaneous solution for use position and GPS orbits, and calibration of atmospheric delays using water vapor radiometers. Sub-decimeter tracking will be first demonstrated on the TOPEX oceanographic satellite to be launched in 1991. A GPS flight receiver together with at least six ground receivers will acquire delta range data from the GPS carriers for non-real-time analysis. Altitude accuracies of 5 to 10 cm are expected. For baseline measurements, efforts will be made to obtain precise differential pseudorange by resolving the cycle ambiguity in differential carrier phase. This could lead to accuracies of 2 or 3 cm over a few thousand kilometers. To achieve this, a high-performance receiver is being developed, along with improved calibration and data processing techniques. Demonstrations may begin in 1986.

A Remote Characterization System and a fault-tolerant tracking system for subsurface mapping of buried waste sites

International Nuclear Information System (INIS)

Sandness, G.A.; Bennett, D.W.; Martinson, L.; Bingham, D.N.; Anderson, A.A.

1992-08-01

This paper describes two closely related projects that will provide new technology for characterizing hazardous waste burial sites. The first project, a collaborative effort by five of the national laboratories, involves the development and demonstration of a remotely controlled site characterization system. The Remote Characterization System (RCS) includes a unique low-signature survey vehicle, a base station, radio telemetry data links, satellite-based vehicle tracking, stereo vision, and sensors for noninvasive inspection of the surface and subsurface. The second project, conducted by the Idaho National Engineering Laboratory (INEL), involves the development of a position sensing system that can track a survey vehicle or instrument in the field. This system can coordinate updates at a rate of 200/s with an accuracy better than 0.1% of the distance separating the target and the sensor. It can employ acoustic or electromagnetic signals in a wide range of frequencies and can be operated as a passive or active device

Sand dune tracking from satellite laser altimetry

Science.gov (United States)

Dabboor, Mohammed

Substantial problems arise from sand movement in arid and semi-arid countries. Sand poses a threat to infrastructure, agricultural and urban areas. These issues are caused by the encroachment of sand on roads and railway tracks, farmland, towns and villages, and airports, to name a few. Sand movement highly depends on geomorphology including vegetation cover, shape and height of the terrain, and grain size of the sand. However, wind direction and speed are the most important factors that affect efficient sand movement. The direction of the movement depends on the main direction of the wind, but it has been shown that a minimum wind speed is required, e.g. wind gusts, to initiate sand transport. This fact prevents a simple calculation of sand transport from conventional wind data as wind records rarely contain sub-minute intervals masking out any wind gusts. An alternative of predicting sand transport is the direct observation of sand advance by in situ measurements or via satellite. Until recently, satellite imagery was the only means to compare dune shape and position for predicting dune migration over several years. In 2003, the NASA laser altimetry mission ICESat became operational and monitors elevations over all surface types including sand dunes with an accuracy of about 10-20 cm. In this study, ICESat observations from repeat tracks (tracks overlapping eachother within 50 m) are used to derive sand dune advance and direction. The method employs a correlation of the elevation profiles over several dunes and was sucessfully validated with synthetic data. The accuracy of this method is 5 meters of dune advance. One of the most active areas exhibiting sand and dune movement is the area of the Arabian Peninsula. Approximately one-third of the Arabian Peninsula is covered by sand dunes. Different wind regimes (Shamal, Kaus) cause sand dune movement in the selected study area in the eastern part of the Arabian Peninsula between 20-25 degrees North and 45-55 degrees

Hyperspectral Vehicle BRDF Learning: An Exploration of Vehicle Reflectance Variation and Optimal Measures of Spectral Similarity for Vehicle Reacquisition and Tracking Algorithms

Science.gov (United States)

Svejkosky, Joseph

The spectral signatures of vehicles in hyperspectral imagery exhibit temporal variations due to the preponderance of surfaces with material properties that display non-Lambertian bi-directional reflectance distribution functions (BRDFs). These temporal variations are caused by changing illumination conditions, changing sun-target-sensor geometry, changing road surface properties, and changing vehicle orientations. To quantify these variations and determine their relative importance in a sub-pixel vehicle reacquisition and tracking scenario, a hyperspectral vehicle BRDF sampling experiment was conducted in which four vehicles were rotated at different orientations and imaged over a six-hour period. The hyperspectral imagery was calibrated using novel in-scene methods and converted to reflectance imagery. The resulting BRDF sampled time-series imagery showed a strong vehicle level BRDF dependence on vehicle shape in off-nadir imaging scenarios and a strong dependence on vehicle color in simulated nadir imaging scenarios. The imagery also exhibited spectral features characteristic of sampling the BRDF of non-Lambertian targets, which were subsequently verified with simulations. In addition, the imagery demonstrated that the illumination contribution from vehicle adjacent horizontal surfaces significantly altered the shape and magnitude of the vehicle reflectance spectrum. The results of the BRDF sampling experiment illustrate the need for a target vehicle BRDF model and detection scheme that incorporates non-Lambertian BRDFs. A new detection algorithm called Eigenvector Loading Regression (ELR) is proposed that learns a hyperspectral vehicle BRDF from a series of BRDF measurements using regression in a lower dimensional space and then applies the learned BRDF to make test spectrum predictions. In cases of non-Lambertian vehicle BRDF, this detection methodology performs favorably when compared to subspace detections algorithms and graph-based detection algorithms that

Combined Optimal Sizing and Control for a Hybrid Tracked Vehicle

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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.

Automatic tracking of dynamical evolutions of oceanic mesoscale eddies with satellite observation data

Science.gov (United States)

Sun, Liang; Li, Qiu-Yang

2017-04-01

The oceanic mesoscale eddies play a major role in ocean climate system. To analyse spatiotemporal dynamics of oceanic mesoscale eddies, the Genealogical Evolution Model (GEM) based on satellite data is developed, which is an efficient logical model used to track dynamic evolution of mesoscale eddies in the ocean. It can distinguish different dynamic processes (e.g., merging and splitting) within a dynamic evolution pattern, which is difficult to accomplish using other tracking methods. To this end, a mononuclear eddy detection method was firstly developed with simple segmentation strategies, e.g. watershed algorithm. The algorithm is very fast by searching the steepest descent path. Second, the GEM uses a two-dimensional similarity vector (i.e. a pair of ratios of overlap area between two eddies to the area of each eddy) rather than a scalar to measure the similarity between eddies, which effectively solves the ''missing eddy" problem (temporarily lost eddy in tracking). Third, for tracking when an eddy splits, GEM uses both "parent" (the original eddy) and "child" (eddy split from parent) and the dynamic processes are described as birth and death of different generations. Additionally, a new look-ahead approach with selection rules effectively simplifies computation and recording. All of the computational steps are linear and do not include iteration. Given the pixel number of the target region L, the maximum number of eddies M, the number N of look-ahead time steps, and the total number of time steps T, the total computer time is O (LM(N+1)T). The tracking of each eddy is very smooth because we require that the snapshots of each eddy on adjacent days overlap one another. Although eddy splitting or merging is ubiquitous in the ocean, they have different geographic distribution in the Northern Pacific Ocean. Both the merging and splitting rates of the eddies are high, especially at the western boundary, in currents and in "eddy deserts". GEM is useful not only for

UFIR Filtering for GPS-Based Tracking over WSNs with Delayed and Missing Data

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Karen Uribe-Murcia

2018-01-01

Full Text Available In smart cities, vehicles tracking is organized to increase safety by localizing cars using the Global Positioning System (GPS. The GPS-based system provides accurate tracking but is also required to be reliable and robust. As a main estimator, we propose using the unbiased finite impulse response (UFIR filter, which meets these needs as being more robust than the Kalman filter (KF. The UFIR filter is developed for vehicle tracking in discrete-time state-space over wireless sensor networks (WSNs with time-stamped data discretely delayed on k-step-lags and missing data. The state-space model is represented in a way such that the UFIR filter, KF, and H∞ filter can be used universally. Applications are given for measurement data, which are cooperatively transferred from a vehicle to a central station through several nodes with k-step-lags. Better tracking performance of the UFIR filter is shown experimentally.

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.

Using Satellite Imagery to Identify Tornado Damage Tracks and Recovery from the April 27, 2011 Severe Weather Outbreak

Science.gov (United States)

Cole, Tony A.; Molthan, Andrew L.; Bell, Jordan R.

2014-01-01

Emergency response to natural disasters requires coordination between multiple local, state, and federal agencies. Single, relatively weak tornado events may require comparatively simple response efforts; but larger "outbreak" events with multiple strong, long-track tornadoes can benefit from additional tools to help expedite these efforts. Meteorologists from NOAA's National Weather Service conduct field surveys to map tornado tracks, assess damage, and determine the tornado intensity following each event. Moderate and high resolution satellite imagery can support these surveys by providing a high-level view of the affected areas. Satellite imagery could then be used to target areas for immediate survey or to corroborate the results of the survey after it is completed. In this study, the feasibility of using satellite imagery to identify tornado damage tracks was determined by comparing the characteristics of tracks observed from low-earth orbit to tracks assessed during the official NWS storm survey process. Of the 68 NWS confirmed centerlines, 24 tracks (35.3%) could be distinguished from other surface features using satellite imagery. Within each EF category, 0% of EF-0, 3% of EF-1, 50% of EF-2, 77.7% of EF-3, 87.5% of EF-4 and 100% of EF-5 tornadoes were detected. It was shown that satellite data can be used to identify tornado damage tracks in MODIS and ASTER NDVI imagery, where damage to vegetation creates a sharp drop in values though the minimum EF-category which can be detected is dependent upon the type of sensor used and underlying vegetation. Near-real time data from moderate resolution sensors compare favorably to field surveys after the event and suggest that the data can provide some value in the assessment process.

GPS Navigation and Tracking Device

Directory of Open Access Journals (Sweden)

Yahya Salameh Khraisat

2011-10-01

Full Text Available Since the introduction of GPS Navigation systems in the marketplace, consumers and businesses have been coming up with innovative ways to use the technology in their everyday life. GPS Navigation and Tracking systems keep us from getting lost when we are in strange locations, they monitor children when they are away from home, keep track of business vehicles and can even let us know where a philandering partner is at all times. Because of this we attend to build a GPS tracking device to solve the mentioned problems. Our work consists of the GPS module that collects data from satellites and calculates the position information before transmitting them to the user’s PC (of Navigation system or observers (of Tracking System using wireless technology (GSM.

A preliminary study of level 1A data processing of a low–low satellite to satellite tracking mission

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Peng Xu

2015-09-01

Full Text Available With the Gravity Recovery and Climate Experiment (GRACE mission as the prime example, an overview is given on the management and processing of Level 1A data of a low–low satellite to satellite tracking mission. To illustrate the underlying principle and algorithm, a detailed study is made on the K-band ranging (KBR assembly, which includes the measurement principles, modeling of noises, the generation of Level 1A data from that of Level 0 as well as Level 1A to Level 1B data processing.

New Opportunitie s for Small Satellite Programs Provided by the Falcon Family of Launch Vehicles

Science.gov (United States)

Dinardi, A.; Bjelde, B.; Insprucker, J.

2008-08-01

The Falcon family of launch vehicles, developed by Space Exploration Technologies Corporation (SpaceX), are designed to provide the world's lowest cost access to orbit. Highly reliable, low cost launch services offer considerable opportunities for risk reduction throughout the life cycle of satellite programs. The significantly lower costs of Falcon 1 and Falcon 9 as compared with other similar-class launch vehicles results in a number of new business case opportunities; which in turn presents the possibility for a paradigm shift in how the satellite industry thinks about launch services.

Satellite tracking of a young Steppe Eagle from the United Arab ...

African Journals Online (AJOL)

Following recovery and successful rehabilitation, a young Steppe Eagle Aquila nipalensis was tagged with a 45 g GPS satellite transmitter to track its migration and identify potential wintering and summering areas of the species passing through the United Arab Emirates (UAE). The study is part of a larger study on ...

Earth Observatory Satellite system definition study. Report 1: Orbit/launch vehicle trade-off studies and recommendations

Science.gov (United States)

1974-01-01

A summary of the constraints and requirements on the Earth Observatory Satellite (EOS-A) orbit and launch vehicle analysis is presented. The propulsion system (hydrazine) and the launch vehicle (Delta 2910) selected for EOS-A are examined. The rationale for the selection of the recommended orbital altitude of 418 nautical miles is explained. The original analysis was based on the EOS-A mission with the Thematic Mapper and the High Resolution Pointable Imager. The impact of the revised mission model is analyzed to show how the new mission model affects the previously defined propulsion system, launch vehicle, and orbit. A table is provided to show all aspects of the EOS multiple mission concepts. The subjects considered include the following: (1) mission orbit analysis, (2) spacecraft parametric performance analysis, (3) launch system performance analysis, and (4) orbits/launch vehicle selection.

Satellite Imagery Assisted Road-Based Visual Navigation System

Science.gov (United States)

Volkova, A.; Gibbens, P. W.

2016-06-01

There is a growing demand for unmanned aerial systems as autonomous surveillance, exploration and remote sensing solutions. Among the key concerns for robust operation of these systems is the need to reliably navigate the environment without reliance on global navigation satellite system (GNSS). This is of particular concern in Defence circles, but is also a major safety issue for commercial operations. In these circumstances, the aircraft needs to navigate relying only on information from on-board passive sensors such as digital cameras. An autonomous feature-based visual system presented in this work offers a novel integral approach to the modelling and registration of visual features that responds to the specific needs of the navigation system. It detects visual features from Google Earth* build a feature database. The same algorithm then detects features in an on-board cameras video stream. On one level this serves to localise the vehicle relative to the environment using Simultaneous Localisation and Mapping (SLAM). On a second level it correlates them with the database to localise the vehicle with respect to the inertial frame. The performance of the presented visual navigation system was compared using the satellite imagery from different years. Based on comparison results, an analysis of the effects of seasonal, structural and qualitative changes of the imagery source on the performance of the navigation algorithm is presented. * The algorithm is independent of the source of satellite imagery and another provider can be used

Differential GNSS and Vision-Based Tracking to Improve Navigation Performance in Cooperative Multi-UAV Systems

Directory of Open Access Journals (Sweden)

Amedeo Rodi Vetrella

2016-12-01

Full Text Available Autonomous navigation of micro-UAVs is typically based on the integration of low cost Global Navigation Satellite System (GNSS receivers and Micro-Electro-Mechanical Systems (MEMS-based inertial and magnetic sensors to stabilize and control the flight. The resulting navigation performance in terms of position and attitude accuracy may not suffice for other mission needs, such as the ones relevant to fine sensor pointing. In this framework, this paper presents a cooperative UAV navigation algorithm that allows a chief vehicle, equipped with inertial and magnetic sensors, a Global Positioning System (GPS receiver, and a vision system, to improve its navigation performance (in real time or in the post processing phase exploiting formation flying deputy vehicles equipped with GPS receivers. The focus is set on outdoor environments and the key concept is to exploit differential GPS among vehicles and vision-based tracking (DGPS/Vision to build a virtual additional navigation sensor whose information is then integrated in a sensor fusion algorithm based on an Extended Kalman Filter. The developed concept and processing architecture are described, with a focus on DGPS/Vision attitude determination algorithm. Performance assessment is carried out on the basis of both numerical simulations and flight tests. In the latter ones, navigation estimates derived from the DGPS/Vision approach are compared with those provided by the onboard autopilot system of a customized quadrotor. The analysis shows the potential of the developed approach, mainly deriving from the possibility to exploit magnetic- and inertial-independent accurate attitude information.

SeaTrack: Ground station orbit prediction and planning software for sea-viewing satellites

Science.gov (United States)

Lambert, Kenneth S.; Gregg, Watson W.; Hoisington, Charles M.; Patt, Frederick S.

1993-01-01

An orbit prediction software package (Sea Track) was designed to assist High Resolution Picture Transmission (HRPT) stations in the acquisition of direct broadcast data from sea-viewing spacecraft. Such spacecraft will be common in the near future, with the launch of the Sea viewing Wide Field-of-view Sensor (SeaWiFS) in 1994, along with the continued Advanced Very High Resolution Radiometer (AVHRR) series on NOAA platforms. The Brouwer-Lyddane model was chosen for orbit prediction because it meets the needs of HRPT tracking accuracies, provided orbital elements can be obtained frequently (up to within 1 week). Sea Track requires elements from the U.S. Space Command (NORAD Two-Line Elements) for the satellite's initial position. Updated Two-Line Elements are routinely available from many electronic sources (some are listed in the Appendix). Sea Track is a menu-driven program that allows users to alter input and output formats. The propagation period is entered by a start date and end date with times in either Greenwich Mean Time (GMT) or local time. Antenna pointing information is provided in tabular form and includes azimuth/elevation pointing angles, sub-satellite longitude/latitude, acquisition of signal (AOS), loss of signal (LOS), pass orbit number, and other pertinent pointing information. One version of Sea Track (non-graphical) allows operation under DOS (for IBM-compatible personal computers) and UNIX (for Sun and Silicon Graphics workstations). A second, graphical, version displays orbit tracks, and azimuth-elevation for IBM-compatible PC's, but requires a VGA card and Microsoft FORTRAN.

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.

A Robust Vehicle Localization Approach Based on GNSS/IMU/DMI/LiDAR Sensor Fusion for Autonomous Vehicles

Directory of Open Access Journals (Sweden)

Xiaoli Meng

2017-09-01

Full Text Available Precise and robust localization in a large-scale outdoor environment is essential for an autonomous vehicle. In order to improve the performance of the fusion of GNSS (Global Navigation Satellite System/IMU (Inertial Measurement Unit/DMI (Distance-Measuring Instruments, a multi-constraint fault detection approach is proposed to smooth the vehicle locations in spite of GNSS jumps. Furthermore, the lateral localization error is compensated by the point cloud-based lateral localization method proposed in this paper. Experiment results have verified the algorithms proposed in this paper, which shows that the algorithms proposed in this paper are capable of providing precise and robust vehicle localization.

A Robust Vehicle Localization Approach Based on GNSS/IMU/DMI/LiDAR Sensor Fusion for Autonomous Vehicles.

Science.gov (United States)

Meng, Xiaoli; Wang, Heng; Liu, Bingbing

2017-09-18

Precise and robust localization in a large-scale outdoor environment is essential for an autonomous vehicle. In order to improve the performance of the fusion of GNSS (Global Navigation Satellite System)/IMU (Inertial Measurement Unit)/DMI (Distance-Measuring Instruments), a multi-constraint fault detection approach is proposed to smooth the vehicle locations in spite of GNSS jumps. Furthermore, the lateral localization error is compensated by the point cloud-based lateral localization method proposed in this paper. Experiment results have verified the algorithms proposed in this paper, which shows that the algorithms proposed in this paper are capable of providing precise and robust vehicle localization.

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

Science.gov (United States)

2016-03-05

Vehicles in Urban Environments The views, opinions and/or findings contained in this report are those of the author(s) and should not contrued as an...Pine Tree Road Ithaca, NY 14850 -2820 ABSTRACT Probabilistic Tracking and Trajectory Planning for Autonomous Ground Vehicles in Urban Environments...Probabilistic Anticipation for Autonomous Robots in Urban Environments, IEEE Transactions on Robotics, (04 2014): 0. doi: 10.1109/TRO.2013.2291620 Isaac

Stair Climbing Control for 4-DOF Tracked Vehicle Based on Internal Sensors

Directory of Open Access Journals (Sweden)

Daisuke Endo

2017-01-01

Full Text Available In search-and-rescue missions, multi-degrees-of-freedom (DOF tracked robots that are equipped with subtracks are commonly used. These types of robots have superior locomotion performance on rough terrain. However, in teleoperated missions, the performance of tracked robots depends largely on the operators’ ability to control every subtrack appropriately. Therefore, an autonomous traversal function can significantly help in the teleoperation of such robots. In this paper, we propose a planning and control method for 4-DOF tracked robots climbing up/down known stairs automatically based on internal sensors. Experimental results obtained using mockup stairs verify the effectiveness of the proposed method.

Tracking Unmanned Aerial Vehicle CTU FTS - Application of equipment

Directory of Open Access Journals (Sweden)

David Hůlek

2015-10-01

Full Text Available Article which is about the Tracking Unmanned Aerial Vehicle continues in the description of the project development dealing with the utilization of the UAV (unmanned aerial vehicle. Documentation of the project progresses builds on the previous article. In that article the selection of observation and transmission equipment was summarized. In the article, the reader learns about an installation of the equipment on the UAV (helicopter, about an interconnection of the equipment to create complete and functional system, about testing of the UAV, about the solutions of the problems which came into being during testing and about protection of the equipment against unfavourable effects. The location of equipment on the unmanned vehicle was chosen after a considering of several parameters. These parameters are preservation of the functionality or an influence to the balance. To find out how the added equipment affect the centre of gravity of the UAV the tabular method of the centre of gravity calculation was used. The results of the existing work on the project are location and attaching of the equipment to the unmanned vehicle, balance of the unmanned vehicle, solutions of the problems coming into being during the testing and design of the equipment protection against unfavourable effects.

Robotics Vision-based Heuristic Reasoning for Underwater Target Tracking and Navigation

OpenAIRE

Kia, Chua; Arshad, Mohd Rizal

2006-01-01

This paper presents a robotics vision-based heuristic reasoning system for underwater target tracking and navigation. This system is introduced to improve the level of automation of underwater Remote Operated Vehicles (ROVs) operations. A prototype which combines computer vision with an underwater robotics system is successfully designed and developed to perform target tracking and intelligent navigation. This study focuses on developing image processing algorithms and fuzzy inference system ...

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.

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.

Performance-based analysis of current South African semi-trailer designs

CSIR Research Space (South Africa)

Thorogood, R

2009-07-01

Full Text Available , performance based standards, dynamic stability, tractor semi- trailers, directional response, static rollover threshold Introduction South African heavy vehicles are currently designed according to prescriptive standards designed and enforced... productivity. These include Central Tyre Inflation (CTI), on-board weighing, new materials such as Domex and vehicle satellite tracking, all leading towards increased payloads and reduced costs. There have also been improvements in technology...

Side-suspended High- Tc Superconducting Maglev Prototype Vehicle Running at a High Speed in an Evacuated Circular Test Track

International Nuclear Information System (INIS)

Zhou, Dajin; Zhao, Lifeng; Cui, Chenyu; Zhang, Yong; Guo, Jianqiang; Zhao, Yong

2017-01-01

High- T c superconductor (HTS) and permanent magnetic guideway (PMG) based maglev train is intensively studied in China, Japan, Germany and Brazil, mainly through static or vibration test. Amongst these studies, only a few of reports are available for the direct and effective assessment on the dynamic performance of the HTS maglev vehicle by running on a straight or circular PMG track. The highest running speed of these experiments is lower than 50 km/h. In this paper, a side-suspended HTS permanent magnetic guideway maglev system was proposed and constructed in order to increase the running speed in a circular track. By optimizing the arrangement of YBCO bulks besides the PMG, the side-suspended HTS maglev prototype vehicle was successfully running stably at a speed as high as 150 km/h in a circular test track with 6.5 m in diameter, and in an evacuated tube environment, in which the pressure is 5 × 10 3 Pa. (paper)

Side-suspended High-Tc Superconducting Maglev Prototype Vehicle Running at a High Speed in an Evacuated Circular Test Track

Science.gov (United States)

Zhou, Dajin; Zhao, Lifeng; Cui, Chenyu; Zhang, Yong; Guo, Jianqiang; Zhao, Yong

2017-07-01

High-T c superconductor (HTS) and permanent magnetic guideway (PMG) based maglev train is intensively studied in China, Japan, Germany and Brazil, mainly through static or vibration test. Amongst these studies, only a few of reports are available for the direct and effective assessment on the dynamic performance of the HTS maglev vehicle by running on a straight or circular PMG track. The highest running speed of these experiments is lower than 50 km/h. In this paper, a side-suspended HTS permanent magnetic guideway maglev system was proposed and constructed in order to increase the running speed in a circular track. By optimizing the arrangement of YBCO bulks besides the PMG, the side-suspended HTS maglev prototype vehicle was successfully running stably at a speed as high as 150 km/h in a circular test track with 6.5 m in diameter, and in an evacuated tube environment, in which the pressure is 5 × 103 Pa.

Research on Dynamic Coupled Characteristics of A Tracked Vehicle Gearbox

Directory of Open Access Journals (Sweden)

Hui Liu

2011-12-01

Full Text Available A tracked vehicle gearbox is divided into two subsystems-housing and gear train. Dynamic behaviors of the two subsystems are coupled practically. And the coupled characteristics describe the integrative dynamic behaviors of gearbox. This study proposes a coupled simulation model to investigate the interrelationship between dynamics of two subsystems. Multi-source excitations are numerically calculated to provide boundary conditions. The flexibility of transmission shafts and housing is mathematically described based on mode superposition. The coupled dynamic characteristics are analyzed with dynamics simulation computation. The flexibility of housing is one of the main causes to induce the fluctuation of dynamic responses of transmission shafts. The experimental results show that the proposed method is accurate through comparison of simulation results and test data.

A survey on the automatic object tracking technology using video signals

International Nuclear Information System (INIS)

Lee, Jae Cheol; Jun, Hyeong Seop; Choi, Yu Rak; Kim, Jae Hee

2003-01-01

Recently, automatic identification and tracking of the object are actively studied according to the rapid development of signal processing and vision technology using improved hardware and software. The object tracking technology can be applied to various fields such as road watching of the vehicles, weather satellite, traffic observation, intelligent remote video-conferences and autonomous mobile robots. Object tracking system receives subsequent pictures from the camera and detects motions of the objects in these pictures. In this report, we investigate various object tracking techniques such as brightness change using histogram characteristic, differential image analysis, contour and feature extraction, and try to find proper methods that can be used to mobile robots actually

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.

Integrated development of light armored vehicles based on wargaming simulators

Science.gov (United States)

Palmarini, Marc; Rapanotti, John

2004-08-01

Vehicles are evolving into vehicle networks through improved sensors, computers and communications. Unless carefully planned, these complex systems can result in excessive crew workload and difficulty in optimizing the use of the vehicle. To overcome these problems, a war-gaming simulator is being developed as a common platform to integrate contributions from three different groups. The simulator, OneSAF, is used to integrate simplified models of technology and natural phenomena from scientists and engineers with tactics and doctrine from the military and analyzed in detail by operations analysts. This approach ensures the modelling of processes known to be important regardless of the level of information available about the system. Vehicle survivability can be improved as well with better sensors, computers and countermeasures to detect and avoid or destroy threats. To improve threat detection and reliability, Defensive Aids Suite (DAS) designs are based on three complementary sensor technologies including: acoustics, visible and infrared optics and radar. Both active armour and softkill countermeasures are considered. In a typical scenario, a search radar, providing continuous hemispherical coverage, detects and classifies the threat and cues a tracking radar. Data from the tracking radar is processed and an explosive grenade is launched to destroy or deflect the threat. The angle of attack and velocity from the search radar can be used by the soft-kill system to carry out an infrared search and track or an illuminated range-gated scan for the threat platform. Upon detection, obscuration, countermanoeuvres and counterfire can be used against the threat. The sensor suite is completed by acoustic detection of muzzle blast and shock waves. Automation and networking at the platoon level contribute to improved vehicle survivability. Sensor data fusion is essential in avoiding catastrophic failure of the DAS. The modular DAS components can be used with Light Armoured

78 FR 16051 - Vehicle/Track Interaction Safety Standards; High-Speed and High Cant Deficiency Operations

Science.gov (United States)

2013-03-13

..., without the need for obtaining a waiver. In order to take advantage of high cant deficiency operations and... attention. In addition, to improve the process for analyzing data while vehicles are negotiating spiral... the last few decades, computer models of rail vehicles interacting with track have become practical...

Using the Theory of Combined Friction when Making Mathematical Models of Curvilinear Motion of Tracked Vehicles

Directory of Open Access Journals (Sweden)

M. V. Vyaznikov

2014-01-01

Full Text Available The paper presents study results of the nonlinear interaction processes between the supporting surface of the track Assembly and the ground in the contact patch, using the mathematical models of friction. For the case blaskapelle motion of a caterpillar, when the resultant of the elementary friction forces is limited by the coupling due to the sliding tracks on the ground, it appears that the increase of the lateral component leads to a decrease of the longitudinal component and the change of direction of the resulting force. As a result, with increasing angular velocity of the tracked vehicle a longitudinal component of the friction force decreases, which is the geometric factor and is defined by the locus of friction for a given type of soil. In the development of this well-known model is considered the general case of friction, which describes the effect of reducing the coefficient of friction in the contact patch at increasing the angular velocity of rotation. To describe this process is used the model of the combined friction which occurs when the surface of the body is doing at the same time the rotational and translational motion. The resulting expression for the resultant of forces of friction and the moment of resistance to rotation based on the decomposition of the first order Pade for a flat spot track Assembly with ground of rectangular shape. With combined friction any arbitrarily small perturbation force acting parallel to the surface of the contact spot, leads to slip. The paper considers the possibility of using the model of the combined friction to research a sustainability curvilinear motion of tracked vehicles. The proposed motion of the machine in the mode of skidding on the basis of the frictionslip. The interpretation of the physical processes occurring in the contact area, on the basis of the theory of the combined friction would allow using this mathematical model in the algorithm structure of automatic traffic control

Regeneratively-Cooled, Pump-Fed Propulsion Technology for Nano / Micro Satellite Launch Vehicles, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Ventions proposes the development of a pump-fed, 2-stage nano launch vehicle for low-cost on demand placement of cube and nano-satellites into LEO. The proposed...

Estimation of Road Loads and Vibration Transmissibility of Torsion Bar Suspension System in a Tracked Vehicle

Science.gov (United States)

Gagneza, G. P. S.; Chandramohan, Sujatha

2018-05-01

Designing the suspension system of a tracked combat vehicle (CV) is really challenging as it has to satisfy conflicting requirements of good ride comfort, vehicle handling and stability characteristics. Many studies in this field have been reported in literature and it has been found that torsion bars satisfy the designer's conflicting requirements of good ride and handling and thus have reserved a place for themselves as the most widely used suspension system for military track vehicles. Therefore, it is imperative to evaluate the effectiveness of the torsion bar under dynamic conditions of undulating terrain and validating the same by correlating it with computer simulation results. Thus in the present work, the dynamic simulation of a 2N + 4 degrees of freedom (DOF) mathematical model has been carried out using MATLAB Simulink and the vibration levels were also measured experimentally on a 12 wheel stationed high mobility military tracked infantry combat vehicle (ICV BMP-II) traversing different terrain, that is, Aberdeen proving ground (APG) and Sinusoidal, at a constant vehicle speed. The dynamic force transmitted to the hull CG through the 12 torsion bar suspension systems was computed to be around 26,700 N and found to match the measured values. The vibration isolation of the torsion bar in bounce was found to be effective, with a transmissibility from the road wheel to the hull of about 0.6.

Tracking and Data Relay Satellite System user impact and network compatibility study. [antenna design and telecommunication links

Science.gov (United States)

1973-01-01

The report contains data on antenna configurations for the low data rate users of the Tracking and Data Relay Satellite System (TDRSS). It treats the coverage and mutual visibility considerations between the user satellites and the relay satellites and relates these considerations to requirements of antenna beamwidth and fractional user orbital coverage. A final section includes user/TDRS telecommunication link budgets and forward and return link data rate tradeoffs.

Orbit Determination of the SELENE Satellites Using Multi-Satellite Data Types and Evaluation of SELENE Gravity Field Models

Science.gov (United States)

Goossens, S.; Matsumoto, K.; Noda, H.; Araki, H.; Rowlands, D. D.; Lemoine, F. G.

2011-01-01

The SELENE mission, consisting of three separate satellites that use different terrestrial-based tracking systems, presents a unique opportunity to evaluate the contribution of these tracking systems to orbit determination precision. The tracking data consist of four-way Doppler between the main orbiter and one of the two sub-satellites while the former is over the far side, and of same-beam differential VLBI tracking between the two sub-satellites. Laser altimeter data are also used for orbit determination. The contribution to orbit precision of these different data types is investigated through orbit overlap analysis. It is shown that using four-way and VLBI data improves orbit consistency for all satellites involved by reducing peak values in orbit overlap differences that exist when only standard two-way Doppler and range data are used. Including laser altimeter data improves the orbit precision of the SELENE main satellite further, resulting in very smooth total orbit errors at an average level of 18m. The multi-satellite data have also resulted in improved lunar gravity field models, which are assessed through orbit overlap analysis using Lunar Prospector tracking data. Improvements over a pre-SELENE model are shown to be mostly in the along-track and cross-track directions. Orbit overlap differences are at a level between 13 and 21 m with the SELENE models, depending on whether l-day data overlaps or I-day predictions are used.

An adaptive Multiplicative Extened Kalman Filter for Attitude Estimation of Marine Satellite Tracking Antenna

DEFF Research Database (Denmark)

Wang, Yunlong; Soltani, Mohsen; Hussain, Dil muhammed Akbar

2016-01-01

, an adaptive Multiplicative Extended Kalman Filter (MEKF) for attitude estimation of Marine Satellite Tracking Antenna (MSTA) is presented with the measurement noise covariance matrix adjusted according to the norm of accelerometer measurements, which can significantly reduce the slamming influence from waves...

High-order tracking differentiator based adaptive neural control of a flexible air-breathing hypersonic vehicle subject to actuators constraints.

Science.gov (United States)

Bu, Xiangwei; Wu, Xiaoyan; Tian, Mingyan; Huang, Jiaqi; Zhang, Rui; Ma, Zhen

2015-09-01

In this paper, an adaptive neural controller is exploited for a constrained flexible air-breathing hypersonic vehicle (FAHV) based on high-order tracking differentiator (HTD). By utilizing functional decomposition methodology, the dynamic model is reasonably decomposed into the respective velocity subsystem and altitude subsystem. For the velocity subsystem, a dynamic inversion based neural controller is constructed. By introducing the HTD to adaptively estimate the newly defined states generated in the process of model transformation, a novel neural based altitude controller that is quite simpler than the ones derived from back-stepping is addressed based on the normal output-feedback form instead of the strict-feedback formulation. Based on minimal-learning parameter scheme, only two neural networks with two adaptive parameters are needed for neural approximation. Especially, a novel auxiliary system is explored to deal with the problem of control inputs constraints. Finally, simulation results are presented to test the effectiveness of the proposed control strategy in the presence of system uncertainties and actuators constraints. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

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.

Astrometry and Geostationary Satellites in Venezuela

Science.gov (United States)

Lacruz, E.; Abad, C.

2015-10-01

We present the current status and the first results of the astrometric project CIDA - ABAE for tracking geo-stationary satellites. This project aims to determine a preliminary orbit for the Venezuelan satellite VENESAT-1, using astrometric positions obtained from an optical telescope. The results presented here are based on observations from the Luepa space tracking ground station in Venezuela, which were processed using astrometric procedures.

Tracking big and small agriculture with new satellite sensors

Science.gov (United States)

Lobell, D. B.; Azzari, G.; Jin, Z.

2017-12-01

New sensors from both the public and private sector are opening up exciting possibilities for monitoring agriculture and its use of water. This talk will present selected examples from recent work using data from Planet's Planetscope and Skysat sensors as well as Sentinel-1 and Sentinel-2 missions that are part of Europe's Copernicus program. Among other things, these satellites are now helping to track crop types and productivity for fields in rainfed cropping systems of East Africa and irrigated systems in South Asia. This information should contribute to understanding land and water use decisions throughout the world.

S-band multiple-access interference study for advanced tracking and data relay satellite systems

Science.gov (United States)

Peng, Wei-Chung; Yang, Chau-Chin

1990-01-01

The results of a study on the effect of mutual interference among S-band multiple access (SMA) system users of advanced tracking and data relay satellite system (ATDRSS) are presented. In the ATDRSS era, the SMA system is required to support data rates ranging from 10 kb/s to 3 Mb/s. The system will consist of four advanced tracking and data relay satellites (ATDRS) each supporting up to five telemetry links. All users have 10 MHz bandwidth with their carrier frequency equal to 2.2875 GHz. A hybrid SDMA/CDMA scheme is used to mitigate the effect of the interference among system users. SMA system interference probability is evaluated with CLASS software. User link margin degradation due to mutual interference between two users is evaluated. System interference probability is evaluated for the projected 1996 mission model, a reference mission model, and a modified reference mission model.

Cyclone track forecasting based on satellite images using artificial neural networks

OpenAIRE

Kovordanyi, Rita; Roy, Chandan

2009-01-01

Many places around the world are exposed to tropical cyclones and associated storm surges. In spite of massive efforts, a great number of people die each year as a result of cyclone events. To mitigate this damage, improved forecasting techniques must be developed. The technique presented here uses artificial neural networks to interpret NOAA-AVHRR satellite images. A multi-layer neural network, resembling the human visual system, was trained to forecast the movement of cyclones based on sate...

LauncherOne: Virgin Orbit's Dedicated Launch Vehicle for Small Satellites & Impact to the Space Enterprise Vision

Science.gov (United States)

Vaughn, M.; Kwong, J.; Pomerantz, W.

Virgin Orbit is developing a space transportation service to provide an affordable, reliable, and responsive dedicated ride to orbit for smaller payloads. No longer will small satellite users be forced to make a choice between accepting the limitations of flight as a secondary payload, paying dramatically more for a dedicated launch vehicle, or dealing with the added complexity associated with export control requirements and international travel to distant launch sites. Virgin Orbit has made significant progress towards first flight of a new vehicle that will give satellite developers and operators a better option for carrying their small satellites into orbit. This new service is called LauncherOne (See the figure below). LauncherOne is a two stage, air-launched liquid propulsion (LOX/RP) rocket. Air launched from a specially modified 747-400 carrier aircraft (named “Cosmic Girl”), this system is designed to conduct operations from a variety of locations, allowing customers to select various launch azimuths and increasing available orbital launch windows. This provides small satellite customers an affordable, flexible and dedicated option for access to space. In addition to developing the LauncherOne vehicle, Virgin Orbit has worked with US government customers and across the new, emerging commercial sector to refine concepts for resiliency, constellation replenishment and responsive launch elements that can be key enables for the Space Enterprise Vision (SEV). This element of customer interaction is being led by their new subsidiary company, VOX Space. This paper summarizes technical progress made on LauncherOne in the past year and extends the thinking of how commercial space, small satellites and this new emerging market can be brought to bear to enable true space system resiliency.

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.

A stereo vision-based obstacle detection system in vehicles

Science.gov (United States)

Huh, Kunsoo; Park, Jaehak; Hwang, Junyeon; Hong, Daegun

2008-02-01

Obstacle detection is a crucial issue for driver assistance systems as well as for autonomous vehicle guidance function and it has to be performed with high reliability to avoid any potential collision with the front vehicle. The vision-based obstacle detection systems are regarded promising for this purpose because they require little infrastructure on a highway. However, the feasibility of these systems in passenger car requires accurate and robust sensing performance. In this paper, an obstacle detection system using stereo vision sensors is developed. This system utilizes feature matching, epipoplar constraint and feature aggregation in order to robustly detect the initial corresponding pairs. After the initial detection, the system executes the tracking algorithm for the obstacles. The proposed system can detect a front obstacle, a leading vehicle and a vehicle cutting into the lane. Then, the position parameters of the obstacles and leading vehicles can be obtained. The proposed obstacle detection system is implemented on a passenger car and its performance is verified experimentally.

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.

Development of an FPGA Based Embedded System for High Speed Object Tracking

Directory of Open Access Journals (Sweden)

Chandrashekar MATHAM

2010-01-01

Full Text Available This paper deals with the development and implementation of system on chip (SOC for object tracking using histograms. To acquire the distance and velocity information of moving vehicles such as military tanks, to identify the type of target within the range from 100 m to 3 km and to estimate the movements of the vehicle. The VHDL code is written for the above objectives and implemented using Xilinx’s VERTEX-4 based PCI card family.

Tracking of nuclear shipments with automatic vehicle location systems

International Nuclear Information System (INIS)

Colhoun, C.J.K.

1989-01-01

A complete Automatic Vehicle Location System (AVL) consists of three main elements: (1) the location sensor in the vehicle, this device constantly determines the coordinates of the vehicles position; (2) the radio link between vehicle and central base; (3) the data processing and display in the central base. For all three elements there are several solutions. The optimal combination of the different techniques depends on the requirements of the special application

Detection and Tracking of Road Barrier Based on Radar and Vision Sensor Fusion

Directory of Open Access Journals (Sweden)

Taeryun Kim

2016-01-01

Full Text Available The detection and tracking algorithms of road barrier including tunnel and guardrail are proposed to enhance performance and reliability for driver assistance systems. Although the road barrier is one of the key features to determine a safe drivable area, it may be recognized incorrectly due to performance degradation of commercial sensors such as radar and monocular camera. Two frequent cases among many challenging problems are considered with the commercial sensors. The first case is that few tracks of radar to road barrier are detected due to material type of road barrier. The second one is inaccuracy of relative lateral position by radar, thus resulting in large variance of distance between a vehicle and road barrier. To overcome the problems, the detection and estimation algorithms of tracks corresponding to road barrier are proposed. Then, the tracking algorithm based on a probabilistic data association filter (PDAF is used to reduce variation of lateral distance between vehicle and road barrier. Finally, the proposed algorithms are validated via field test data and their performance is compared with that of road barrier measured by lidar.

Tracking- and Scintillation-Aware Channel Model for GEO Satellite to Land Mobile Terminals at Ku-Band

Directory of Open Access Journals (Sweden)

Ali M. Al-Saegh

2015-01-01

Full Text Available Recent advances in satellite to land mobile terminal services and technologies, which utilize high frequencies with directional antennas, have made the design of an appropriate model for land mobile satellite (LMS channels a necessity. This paper presents LMS channel model at Ku-band with features that enhance accuracy, comprehensiveness, and reliability. The effect of satellite tracking loss at different mobile terminal speeds is considered for directional mobile antenna systems, a reliable tropospheric scintillation model for an LMS scenario at tropical and temperate regions is presented, and finally a new quality indicator module for different modulation and coding schemes is included. The proposed extended LMS channel (ELMSC model is designed based on actual experimental measurements and can be applied to narrow- and wide-band signals at different regions and at different speeds and multichannel states. The proposed model exhibits lower root mean square error (RMSE and significant performance observation compared with the conventional model in terms of the signal fluctuations, fade depth, signal-to-noise ratio (SNR, and quality indicators accompanied for several transmission schemes.

Soft Sensor of Vehicle State Estimation Based on the Kernel Principal Component and Improved Neural Network

Directory of Open Access Journals (Sweden)

Haorui Liu

2016-01-01

Full Text Available In the car control systems, it is hard to measure some key vehicle states directly and accurately when running on the road and the cost of the measurement is high as well. To address these problems, a vehicle state estimation method based on the kernel principal component analysis and the improved Elman neural network is proposed. Combining with nonlinear vehicle model of three degrees of freedom (3 DOF, longitudinal, lateral, and yaw motion, this paper applies the method to the soft sensor of the vehicle states. The simulation results of the double lane change tested by Matlab/SIMULINK cosimulation prove the KPCA-IENN algorithm (kernel principal component algorithm and improved Elman neural network to be quick and precise when tracking the vehicle states within the nonlinear area. This algorithm method can meet the software performance requirements of the vehicle states estimation in precision, tracking speed, noise suppression, and other aspects.

Software Design of Mobile Antenna for Auto Satellite Tracking Using Modem Correction and Elevation Azimuth Method

Directory of Open Access Journals (Sweden)

Djamhari Sirat

2010-10-01

Full Text Available Pointing accuracy is an important thing in satellite communication. Because the satellite’s distance to the surface of the earth's satellite is so huge, thus 1 degree of pointing error will make the antenna can not send data to satellites. To overcome this, the auto-tracking satellite controller is made. This system uses a microcontroller as the controller, with the GPS as the indicator location of the antenna, digital compass as the beginning of antenna pointing direction, rotary encoder as sensor azimuth and elevation, and modem to see Eb/No signal. The microcontroller use serial communication to read the input. Thus the programming should be focused on in the UART and serial communication software UART. This controller use 2 phase in the process of tracking satellites. Early stages is the method Elevation-Azimuth, where at this stage with input from GPS, Digital Compass, and the position of satellites (both coordinates, and height that are stored in microcontroller. Controller will calculate the elevation and azimuth angle, then move the antenna according to the antenna azimuth and elevation angle. Next stages is correction modem, where in this stage controller only use modem as the input, and antenna movement is set up to obtain the largest value of Eb/No signal. From the results of the controller operation, there is a change in the value of the original input level from -81.7 dB to -30.2 dB with end of Eb/No value, reaching 5.7 dB.

VEHICLE TRACKING AND MONITORING SYSTEM USING GPS AND GSM/GPRS.

OpenAIRE

*Arsheen Barnagarwala, *Aziz Buriwala

2017-01-01

Abstract: This system offers an affordable and compact design implemented for tracking and monitoring vehicle’s Instantaneous speed, peak speed, distance and current location with the help of Global Positioning System (GPS) and Global System for Mobile Communication (GSM). The system consist of two parts, one is ambulatory and incorporated in the target vehicle which comprises of a GPS receiver, a microcontroller and a GSM modem with periphery display and power units. Other is stable at a rem...

Powertrain preheating system of tracked hybrid electric vehicle in cold weather

International Nuclear Information System (INIS)

Wang, Rui; Wang, Yichun; Feng, Chaoqing; Zhang, Xilong

2015-01-01

In order to make sure that the heavy duty tracked vehicle can work in various conditions, especially severe cold weather, preheating system of powertrain should be adopted, and a novel preheating system is presented for the tracked hybrid electric vehicle (HEV) in which heat is generated by the low-speed drive motor. The new preheating system can meet the need of cold start without adding any additional device. The characteristic of heat generation by motor is tested when the rotor of motor is rotated in very low speed. The heat loss from power cabin to external environment has been simulated, and the relevant test has been done to verify the simulation results. Combining the characteristic of heat generation and heat loss situation about preheating system, the heat transfer model of preheating system was implemented by MATLAB. The total energy required for preheating in different ambient temperature was calculated by this model. The results showed that: the minimum heating power was 70 kW and energy required was about 180 MJ when the HEV worked in −46 °C. If lithium ferrous phosphate (LFP) battery was used in power system, the minimum battery capacity is about 290 A h. - Highlights: • A novel preheating method was proposed for heavy duty tracked HEV. • Thermal energy in preheating system is produced by the PMSM in driving system. • This method can achieve preheating target by its own components without any adding. • Analyzing low temperature performance of power battery and select its capacity.

A Customized Vision System for Tracking Humans Wearing Reflective Safety Clothing from Industrial Vehicles and Machinery

Science.gov (United States)

Mosberger, Rafael; Andreasson, Henrik; Lilienthal, Achim J.

2014-01-01

This article presents a novel approach for vision-based detection and tracking of humans wearing high-visibility clothing with retro-reflective markers. Addressing industrial applications where heavy vehicles operate in the vicinity of humans, we deploy a customized stereo camera setup with active illumination that allows for efficient detection of the reflective patterns created by the worker's safety garments. After segmenting reflective objects from the image background, the interest regions are described with local image feature descriptors and classified in order to discriminate safety garments from other reflective objects in the scene. In a final step, the trajectories of the detected humans are estimated in 3D space relative to the camera. We evaluate our tracking system in two industrial real-world work environments on several challenging video sequences. The experimental results indicate accurate tracking performance and good robustness towards partial occlusions, body pose variation, and a wide range of different illumination conditions. PMID:25264956

An Orientation Sensor-Based Head Tracking System for Driver Behaviour Monitoring

Directory of Open Access Journals (Sweden)

Yifan Zhao

2017-11-01

Full Text Available Although at present legislation does not allow drivers in a Level 3 autonomous vehicle to engage in a secondary task, there may become a time when it does. Monitoring the behaviour of drivers engaging in various non-driving activities (NDAs is crucial to decide how well the driver will be able to take over control of the vehicle. One limitation of the commonly used face-based head tracking system, using cameras, is that sufficient features of the face must be visible, which limits the detectable angle of head movement and thereby measurable NDAs, unless multiple cameras are used. This paper proposes a novel orientation sensor based head tracking system that includes twin devices, one of which measures the movement of the vehicle while the other measures the absolute movement of the head. Measurement error in the shaking and nodding axes were less than 0.4°, while error in the rolling axis was less than 2°. Comparison with a camera-based system, through in-house tests and on-road tests, showed that the main advantage of the proposed system is the ability to detect angles larger than 20° in the shaking and nodding axes. Finally, a case study demonstrated that the measurement of the shaking and nodding angles, produced from the proposed system, can effectively characterise the drivers’ behaviour while engaged in the NDAs of chatting to a passenger and playing on a smartphone.

Video-based lane estimation and tracking for driver assistance: Survey, system, and evaluation

OpenAIRE

McCall, J C; Trivedi, Mohan Manubhai

2006-01-01

Driver-assistance systems that monitor driver intent, warn drivers of lane departures, or assist in vehicle guidance are all being actively considered. It is therefore important to take a critical look at key aspects of these systems, one of which is lane-position tracking. It is for these driver-assistance objectives that motivate the development of the novel "video-based lane estimation and tracking" (VioLET) system. The system is designed using steerable filters for robust and accurate lan...

European Telecommunications Satellite II (EUTELSAT II)

Science.gov (United States)

Laemmel, G.; Brittinger, P.

1991-01-01

EUTELSAT II is a regional public telecommunications system for Europe. The services which will be provided are telephone and television. The satellites will be placed at a geostationary orbit within the arcs of 6 degrees east to 19 degrees east or 26 degrees to 36 degrees east. The designed lifetime is 7 years. After separation of the satellites from the launch vehicles, telemetry, telecommand, and ranging will be performed within the S-band frequencies. After positioning of the satellite at its final geostationary orbit, the Ku-band telecommunication equipment will be activated. From this time on, all satellite control operations will be performed in Ku-band. The Deep Space Network (DSN) will support the transfer and drift orbit mission phases. The coverage will consist of the 26-m antennas at Goldstone and Canberra as prime support for the transfer and drift orbits. Maximum support will consist of a 7-day period, plus 14 days of contingency support. Information is given in tabular form for DSN support, frequency assignments, telemetry, command, and tracking support responsibility.

The along track scanning radiometer - an analysis of coincident ship and satellite measurements

Science.gov (United States)

Barton, I. J.; Prata, A. J.; Llewellyn-Jones, D. T.

1993-05-01

Following the successful launch of the ERS-1 satellite in July 1991 we have undertaken several geophysical validation cruises in the Coral Sea. The prime aim of these cruises was to compare the sea surface temperature (SST) derived from the Along Track Scanning Radiometer (ATSR) with that measured using precision radiometers mounted on the ships. On most occasions when simultaneous satellite and ship measurements were taken we also launched a radiosonde from one of the research vessels. The results suggest that the ATSR is able to measure the ``skin'' temperature of the sea surface with an accuracy suitable for climate research applications. A case study comparison between the AVHRR and ATSR SST products will also be presented.

Fuzzy Sliding Mode Lateral Control of Intelligent Vehicle Based on Vision

Directory of Open Access Journals (Sweden)

Linhui Li

2013-01-01

Full Text Available The lateral control of intelligent vehicle is studied in this paper, with the intelligent vehicle DLUIV-1 based on visual navigation as the object of research. Firstly, the lateral control model based on visual preview is established. The kinematics model based on visual preview, including speed and other factors, is used to calculate the lateral error and direction error. Secondly, according to the characteristics of lateral control, an efficient strategy of intelligent vehicle lateral mode is proposed. The integration of the vehicle current lateral error and direction error is chosen as the parameter of the sliding mode switching function to design the sliding surface. The control variables are adjusted according to the fuzzy control rules to ensure that they meet the existence and reaching condition. The sliding mode switching function is regarded as the control objective, to ensure the stability of the steering wheel rotation. Simulation results show that the lateral controller can guarantee high path-tracking accuracy and strong robustness for the change of model parameters.

Integration of Satellite Tracking Data and Satellite Images for Detailed Characteristics of Wildlife Habitats

Science.gov (United States)

Dobrynin, D. V.; Rozhnov, V. V.; Saveliev, A. A.; Sukhova, O. V.; Yachmennikova, A. A.

2017-12-01

Methods of analysis of the results got from satellite tracking of large terrestrial mammals differ in the level of their integration with additional geographic data. The reliable fine-scale cartographic basis for assessing specific wildlife habitats can be developed through the interpretation of multispectral remote sensing data and extrapolation of the results to the entire estimated species range. Topographic maps were ordinated according to classified features using self-organizing maps (Kohonen's SOM). The satellite image of the Ussuriiskyi Nature Reserve area was interpreted for the analysis of movement conditions for seven wild Amur tigers ( Panthera tigris altaica) equipped with GPS collars. 225 SOM classes for cartographic visualization are sufficient for the detailed mapping of all natural complexes that were identified as a result of interpretation. During snow-free periods, tigers preferred deciduous and shrub associations at lower elevations, as well as mixed forests in the valleys of streams that are adjacent to sparse forests and shrub watershed in the mountain ranges; during heavy snow periods, the animals preferred the entire range of plant communities in different relief types, except for open sites in meadows and abandoned fields at foothills. The border zones of different biotopes were typically used by the tigers during all seasons. Amur tigers preferred coniferous forests for long-term movements.

NASA to launch second business communications satellite

Science.gov (United States)

1981-01-01

The two stage Delta 3910 launch vehicle was chosen to place the second small business satellite (SBS-B) into a transfer orbit with an apogee of 36,619 kilometers and a perigee of 167 km, at an inclination of 27.7 degrees to Earth's equator. The firing and separation sequence and the inertial guidance system are described as well as the payload assist module. Facilities and services for tracking and control by NASA, COMSAT, Intelsat, and SBS are outlined and prelaunch operations are summarized.

New insights into the short pitch corrugation development enigma based on 3D-FE dynamic vehicle-track coupled modelling in frictional rolling contact

NARCIS (Netherlands)

Li, S.; Li, Z.; Nunez Vicencio, Alfredo; Dollevoet, R.P.B.J.

2017-01-01

A three-dimensional (3D) finite element (FE) dynamic frictional rolling contact model is presented for the study of short pitch corrugation that considers direct and instantaneous coupling between the contact mechanics and the structural dynamics in a vehicle-track system. In this study, we examine

Track in the field : telematics services are improving efficiency and safety by closing the communications gap

Energy Technology Data Exchange (ETDEWEB)

Budd, G.

2010-09-15

High-tech wireless communications tools and equipment monitoring systems are available to fleet vehicle managers who must deal with a variety of hazards, including inadequate equipment diagnostics, irregular vehicle maintenance, employees with erratic driving habits and service roads in remote locations. This paper described Quadrant, a web-based software developed by WebTech Wireless Inc. The tracking and reporting software integrated a global positioning system with cellular and satellite technology, vehicle monitoring systems, and software applications to provide clients with a range of critical data in an automated real-time basis. The data include information on vehicle location, speeding incidents, idling duration, distances, braking and acceleration patterns, fuel usage and engine diagnostic trouble codes. To accommodate Alberta's oilpatch, WebTech added an overlay of Alberta's legal subdivision grid to its mapping system to include relevant off-highway and rural data. Emergency systems have been modified for sites that ban all radio transmission. 1 ref., 1 fig.

Space Solar Power Satellite Systems, Modern Small Satellites, and Space Rectenna

Science.gov (United States)

Bergsrud, Corey Alexis Marvin

Space solar power satellite (SSPS) systems is the concept of placing large satellite into geostationary Earth orbit (GEO) to harvest and convert massive amounts of solar energy into microwave energy, and to transmit the microwaves to a rectifying antenna (rectenna) array on Earth. The rectenna array captures and converts the microwave power into usable power that is injected into the terrestrial electric grid for use. This work approached the microwave power beam as an additional source of power (with solar) for lower orbiting satellites. Assuming the concept of retrodirectivity, a GEO-SSPS antenna array system tracks and delivers microwave power to lower orbiting satellites. The lower orbiting satellites are equipped with a stacked photovoltaic (PV)/rectenna array hybrid power generation unit (HPGU) in order to harvest solar and/or microwave energy for on-board use during orbit. The area, and mass of the PV array part of the HPGU was reduced at about 32% beginning-of-life power in order to achieve the spacecraft power requirements. The HPGU proved to offer a mass decrease in the PGU, and an increase in mission life due to longer living component life of the rectenna array. Moreover, greater mission flexibility is achieved through a track and power delivery concept. To validate the potential advantages offered by a HPGU, a mission concept was presented that utilizes modern small satellites as technology demonstrators. During launch, a smaller power receiving "daughter" satellite sits inside a larger power transmitting "mother" satellite. Once separated from the launch vehicle the daughter satellite is ejected away from the mother satellite, and each satellite deploys its respective power transmitting or power receiving hardware's for experimentation. The concept of close proximity mission operations between the satellites is considered. To validate the technology of the space rectenna array part of the HPGU, six milestones were completed in the design. The first

Multi-GNSS orbit determination using satellite laser ranging

Science.gov (United States)

Bury, Grzegorz; Sośnica, Krzysztof; Zajdel, Radosław

2018-04-01

Galileo, BeiDou, QZSS, and NavIC are emerging global navigation satellite systems (GNSSs) and regional navigation satellite systems all of which are equipped with laser retroreflector arrays for range measurements. This paper summarizes the GNSS-intensive tracking campaigns conducted by the International Laser Ranging Service and provides results from multi-GNSS orbit determination using solely SLR observations. We consider the whole constellation of GLONASS, all active Galileo, four BeiDou satellites: 1 MEO, 3 IGSO, and one QZSS. We analyze the influence of the number of SLR observations on the quality of the 3-day multi-GNSS orbit solution. About 60 SLR observations are needed for obtaining MEO orbits of sufficient quality with the root mean square (RMS) of 3 cm for the radial component when compared to microwave-based orbits. From the analysis of a minimum number of tracking stations, when considering the 3-day arcs, 5 SLR stations do not provide a sufficient geometry of observations. The solution obtained using ten stations is characterized with RMS of 4, 9, and 18 cm in the radial, along-track, and cross-track direction, respectively, for MEO satellites. We also investigate the impact of the length of orbital arc on the quality of SLR-derived orbits. Hence, 5- and 7-day arcs constitute the best solution, whereas 3-day arcs are of inferior quality due to an insufficient number of SLR observations and 9-day arcs deteriorate the along-track component. The median RMS from the comparison between 7-day orbital arcs determined using SLR data with microwave-based orbits assumes values in the range of 3-4, 11-16, and 15-27 cm in radial, along-track, and cross-track, respectively, for MEO satellites. BeiDou IGSO and QZSS are characterized by RMS values higher by a factor of 8 and 24, respectively, than MEO orbits.

Advanced laser-based tracking device for motor vehicle lane position monitoring and steering assistance

Science.gov (United States)

Bachalo, William D.; Inenaga, Andrew; Schuler, Carlos A.

1995-12-01

Aerometrics is developing an innovative laser-diode based device that provides a warning signal when a motor-vehicle deviates from the center of the lane. The device is based on a sensor that scans the roadway on either side of the vehicle and determines the lateral position relative to the existing painted lines marking the lane. No additional markings are required. A warning is used to alert the driver of excessive weaving or unanticipated departure from the center of the lane. The laser beams are at invisible wavelengths to that operation of the device does not pose a distraction to the driver or other motorists: When appropriate markers are not present on the road, the device is capable of detecting this condition and warn the driver. The sensor system is expected to work well irrespective of ambient light levels, fog and rain. This sensor has enormous commercial potential. It could be marketed as an instrument to warn drivers that they are weaving, used as a research tool to monitor driving patterns, be required equipment for those previously convicted of driving under the influence, or used as a backup sensor for vehicle lateral position control. It can also be used in storage plants to guide robotic delivery vehicles. In this paper, the principles of operation of the sensor, and the results of Aerometrics ongoing testing will be presented.

Design and control of the precise tracking bed based on complex electromechanical design theory

Science.gov (United States)

Ren, Changzhi; Liu, Zhao; Wu, Liao; Chen, Ken

2010-05-01

The precise tracking technology is wide used in astronomical instruments, satellite tracking and aeronautic test bed. However, the precise ultra low speed tracking drive system is one high integrated electromechanical system, which one complexly electromechanical design method is adopted to improve the efficiency, reliability and quality of the system during the design and manufacture circle. The precise Tracking Bed is one ultra-exact, ultra-low speed, high precision and huge inertial instrument, which some kind of mechanism and environment of the ultra low speed is different from general technology. This paper explores the design process based on complex electromechanical optimizing design theory, one non-PID with a CMAC forward feedback control method is used in the servo system of the precise tracking bed and some simulation results are discussed.

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.

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.

German telecommunications satellite (Deutscher fernmelde satellit) (DFS-1 and -2)

Science.gov (United States)

Hiendlmeier, G.; Schmeller, H.

1991-01-01

The German Telecommunications Satellite (DFS) Program is to provide telecommunications service for high data rate transmission of text and video data to the Federal Republic of Germany within the 11-14 GHz and 20-30 GHz bands. The space segment of this program is composed of three satellites, DFS-1, DFS-2, and DFS-3, which will be located at 23.5 degrees E longitude of the geostationary orbit. The DFS will be launched from the Center Spatial Guyanis in French Giana on an Ariane launch vehicle. The mission follows the typical injection sequence: parking orbit, transfer orbit, and earth orbit. Attitude maneuvers will be performed to orient the spacecraft prior to Apogee Kick Motor (AKM) firing. After AKM firing, drift phase orbital and attitude maneuvers will be performed to place the spacecraft in its final geostationary position. The Deep Space Network (DSN) will support the transfer and drift orbit mission phases. Information is presented in tabular form for the following areas: DSN support, compatibility testing, frequency assignments, telemetry, command, and tracking support responsibilities.

Neural network based satellite tracking for deep space applications

Science.gov (United States)

Amoozegar, F.; Ruggier, C.

2003-01-01

The objective of this paper is to provide a survey of neural network trends as applied to the tracking of spacecrafts in deep space at Ka-band under various weather conditions and examine the trade-off between tracing accuracy and communication link performance.

AN AUTONOMOUS GPS-DENIED UNMANNED VEHICLE PLATFORM BASED ON BINOCULAR VISION FOR PLANETARY EXPLORATION

Directory of Open Access Journals (Sweden)

M. Qin

2018-04-01

Full Text Available Vision-based navigation has become an attractive solution for autonomous navigation for planetary exploration. This paper presents our work of designing and building an autonomous vision-based GPS-denied unmanned vehicle and developing an ARFM (Adaptive Robust Feature Matching based VO (Visual Odometry software for its autonomous navigation. The hardware system is mainly composed of binocular stereo camera, a pan-and tilt, a master machine, a tracked chassis. And the ARFM-based VO software system contains four modules: camera calibration, ARFM-based 3D reconstruction, position and attitude calculation, BA (Bundle Adjustment modules. Two VO experiments were carried out using both outdoor images from open dataset and indoor images captured by our vehicle, the results demonstrate that our vision-based unmanned vehicle is able to achieve autonomous localization and has the potential for future planetary exploration.

An Autonomous Gps-Denied Unmanned Vehicle Platform Based on Binocular Vision for Planetary Exploration

Science.gov (United States)

Qin, M.; Wan, X.; Shao, Y. Y.; Li, S. Y.

2018-04-01

Vision-based navigation has become an attractive solution for autonomous navigation for planetary exploration. This paper presents our work of designing and building an autonomous vision-based GPS-denied unmanned vehicle and developing an ARFM (Adaptive Robust Feature Matching) based VO (Visual Odometry) software for its autonomous navigation. The hardware system is mainly composed of binocular stereo camera, a pan-and tilt, a master machine, a tracked chassis. And the ARFM-based VO software system contains four modules: camera calibration, ARFM-based 3D reconstruction, position and attitude calculation, BA (Bundle Adjustment) modules. Two VO experiments were carried out using both outdoor images from open dataset and indoor images captured by our vehicle, the results demonstrate that our vision-based unmanned vehicle is able to achieve autonomous localization and has the potential for future planetary exploration.

Development of a PC-based ground support system for a small satellite instrument

Science.gov (United States)

Deschambault, Robert L.; Gregory, Philip R.; Spenler, Stephen; Whalen, Brian A.

1993-11-01

The importance of effective ground support for the remote control and data retrieval of a satellite instrument cannot be understated. Problems with ground support may include the need to base personnel at a ground tracking station for extended periods, and the delay between the instrument observation and the processing of the data by the science team. Flexible solutions to such problems in the case of small satellite systems are provided by using low-cost, powerful personal computers and off-the-shelf software for data acquisition and processing, and by using Internet as a communication pathway to enable scientists to view and manipulate satellite data in real time at any ground location. The personal computer based ground support system is illustrated for the case of the cold plasma analyzer flown on the Freja satellite. Commercial software was used as building blocks for writing the ground support equipment software. Several levels of hardware support, including unit tests and development, functional tests, and integration were provided by portable and desktop personal computers. Satellite stations in Saskatchewan and Sweden were linked to the science team via phone lines and Internet, which provided remote control through a central point. These successful strategies will be used on future small satellite space programs.

Road Vehicle Monitoring System Based on Intelligent Visual Internet of Things

Directory of Open Access Journals (Sweden)

Qingwu Li

2015-01-01

Full Text Available In recent years, with the rapid development of video surveillance infrastructure, more and more intelligent surveillance systems have employed computer vision and pattern recognition techniques. In this paper, we present a novel intelligent surveillance system used for the management of road vehicles based on Intelligent Visual Internet of Things (IVIoT. The system has the ability to extract the vehicle visual tags on the urban roads; in other words, it can label any vehicle by means of computer vision and therefore can easily recognize vehicles with visual tags. The nodes designed in the system can be installed not only on the urban roads for providing basic information but also on the mobile sensing vehicles for providing mobility support and improving sensing coverage. Visual tags mentioned in this paper consist of license plate number, vehicle color, and vehicle type and have several additional properties, such as passing spot and passing moment. Moreover, we present a fast and efficient image haze removal method to deal with haze weather condition. The experiment results show that the designed road vehicle monitoring system achieves an average real-time tracking accuracy of 85.80% under different conditions.

Positioning Reduction of Deep Space Probes Based on VLBI Tracking

Science.gov (United States)

Qiao, S. B.

2011-11-01

In the background of the Chinese Lunar Exploration Project and the Yinghuo Project, through theoretical analysis, algorithm study, software development, data simulation, real data processing and so on, the positioning reductions of the European lunar satellite Smart-1 and Mars Express (MEX) satellite, as well as the Chinese Chang'e-1 (CE-1) and Chang'e-2 (CE-2) satellites are accomplished by using VLBI and USB tracking data in this dissertation. The progress is made in various aspects including the development of theoretical model, the construction of observation equation, the analysis of the condition of normal equation, the selection and determination of the constraint, the analysis of data simulation, the detection of outliers in observations, the maintenance of the stability of the solution of parameters, the development of the practical software system, the processing of the real tracking data and so on. The details of the research progress in this dissertation are written as follows: (1) The algorithm is analyzed concerning the positioning reduction of the deep spacecraft based on VLBI tracking data. Through data simulation, it is analyzed for the effects of the bias in predicted orbit, the white noises and systematic errors in VLBI delays, and USB ranges on the positioning reduction of spacecraft. Results show that it is preferable to suppress the dispersion of positioning data points by applying the constraint of geocentric distance of spacecraft when there are only VLBI tracking data. The positioning solution is a biased estimate via observations of three VLBI stations. For the case of four tracking stations, the uncertainty of the constraint should be in accordance with the bias in the predicted orbit. White noises in delays and ranges mainly result in dispersion of the sequence of positioning data points. If there is the systematic error of observations, the systematic offset of the positioning results is caused, and there are trend jumps in the shape of

Satellite tracking and stable isotope analysis link wintering and feeding grounds of North Atlantic baleen whales

NARCIS (Netherlands)

e Silva, Monica Almeida; Prieto, Rui; Gauffier, Pauline; Palsboll, Per; Bérubé, Martine; Colaco, Ana

2017-01-01

Knowledge of the distribution of baleen whales throughout their annual cycle is critical for understanding their ecology, life history and behavior, and for their effective conservation. We combined analysis of stable isotopes (δ15N and δ13C) and satellite tracking data of blue (Balaenoptera

Automated time activity classification based on global positioning system (GPS) tracking data.

Science.gov (United States)

Wu, Jun; Jiang, Chengsheng; Houston, Douglas; Baker, Dean; Delfino, Ralph

2011-11-14

Air pollution epidemiological studies are increasingly using global positioning system (GPS) to collect time-location data because they offer continuous tracking, high temporal resolution, and minimum reporting burden for participants. However, substantial uncertainties in the processing and classifying of raw GPS data create challenges for reliably characterizing time activity patterns. We developed and evaluated models to classify people's major time activity patterns from continuous GPS tracking data. We developed and evaluated two automated models to classify major time activity patterns (i.e., indoor, outdoor static, outdoor walking, and in-vehicle travel) based on GPS time activity data collected under free living conditions for 47 participants (N = 131 person-days) from the Harbor Communities Time Location Study (HCTLS) in 2008 and supplemental GPS data collected from three UC-Irvine research staff (N = 21 person-days) in 2010. Time activity patterns used for model development were manually classified by research staff using information from participant GPS recordings, activity logs, and follow-up interviews. We evaluated two models: (a) a rule-based model that developed user-defined rules based on time, speed, and spatial location, and (b) a random forest decision tree model. Indoor, outdoor static, outdoor walking and in-vehicle travel activities accounted for 82.7%, 6.1%, 3.2% and 7.2% of manually-classified time activities in the HCTLS dataset, respectively. The rule-based model classified indoor and in-vehicle travel periods reasonably well (Indoor: sensitivity > 91%, specificity > 80%, and precision > 96%; in-vehicle travel: sensitivity > 71%, specificity > 99%, and precision > 88%), but the performance was moderate for outdoor static and outdoor walking predictions. No striking differences in performance were observed between the rule-based and the random forest models. The random forest model was fast and easy to execute, but was likely less robust

Satellite tracking reveals habitat use by juvenile green sea turtles Chelonia mydas in the Everglades, Florida, USA

Science.gov (United States)

Hart, Kristen M.; Fujisaki, Ikuko

2010-01-01

We tracked the movements of 6 juvenile green sea turtles captured in coastal areas of southwest Florida within Everglades National Park (ENP) using satellite transmitters for periods of 27 to 62 d in 2007 and 2008 (mean ± SD: 47.7 ± 12.9 d). Turtles ranged in size from 33.4 to 67.5 cm straight carapace length (45.7 ± 12.9 cm) and 4.4 to 40.8 kg in mass (16.0 ± 13.8 kg). These data represent the first satellite tracking data gathered on juveniles of this endangered species at this remote study site, which may represent an important developmental habitat and foraging ground. Satellite tracking results suggested that these immature turtles were resident for several months very close to capture and release sites, in waters from 0 to 10 m in depth. Mean home range for this springtime tracking period as represented by minimum convex polygon (MCP) was 1004.9 ± 618.8 km2 (range 374.1 to 2060.1 km2), with 4 of 6 individuals spending a significant proportion of time within the ENP boundaries in 2008 in areas with dense patches of marine algae. Core use areas determined by 50% kernel density estimates (KDE) ranged from 5.0 to 54.4 km2, with a mean of 22.5 ± 22.1 km2. Overlap of 50% KDE plots for 6 turtles confirmed use of shallow-water nearshore habitats =0.6 m deep within the park boundary. Delineating specific habitats used by juvenile green turtles in this and other remote coastal areas with protected status will help conservation managers to prioritize their efforts and increase efficacy in protecting endangered species.

iSAT: The Integrated Satellite and Acoustic Telemetry system for tracking marine megafauna

KAUST Repository

De La Torre, Pedro R.

2014-05-01

In this dissertation an innovative technology to study whale sharks, Rhincodon typus is presented. The Integrated Satellite and Acoustic Telemetry project (iSAT) combines underwater acoustic telemetry, autonomous navigation and radio frequency communications into a standalone system. The whale shark, a resident of the Saudi Arabian Red Sea, is the target of the study. The technology presented is designed to help close current gaps in the knowledge of whale shark biology; these are gaps that prohibit the design of optimal conservation strategies. Unfortunately, the various existing tracking technologies each have limitations and are unable to solve all the unanswered questions. Whale shark populations are increasingly threatened by anthropogenic activities such as targeted and indirect fishing pressure, creating an urgent need for better management practices. This dissertation addresses the current state-of-the-art of relevant technologies, including autonomous surface vehicles (ASVs), sensors for research in the ocean and remote monitoring of wild fauna (biotelemetry). iSAT contains components of all of these technologies, but the primary achievement of this dissertation is the development of iSAT’s Acoustic Tracking System (ATS). Underwater, the most efficient way of transmitting energy through long distances is sound. An electronic tag is attached to an animal and works as its acoustic identifier. iSAT’s hydrophone array detects the presence and direction of the acoustic signal generated by the tag. The expected performance, range, and capacity to tell the direction to the tag are explained and compared to the actual measured values. The first operational iSAT ATS is demonstrated. This work represents significant advancement towards a fully autonomous iSAT system. Developments on the power electronics, navigation, renewable energy harvesting, and other modules are included in this research. With the recent integration of digital acquisition systems, i

Mathematical pointing model establishment of the visual tracking theodolite for satellites in two kinds of observation methods.

Science.gov (United States)

Zhang, Yuncheng

The mathematical pointing model is establishment of the visual tracking theodolite for satellites in two kinds of observation methods at Yunnan Observatory, which is related to the digitalisation reform and the optical-electronic technique reform, is introduced respectively in this paper.

A Robust Vision-based Runway Detection and Tracking Algorithm for Automatic UAV Landing

KAUST Repository

Abu Jbara, Khaled F.

2015-05-01

This work presents a novel real-time algorithm for runway detection and tracking applied to the automatic takeoff and landing of Unmanned Aerial Vehicles (UAVs). The algorithm is based on a combination of segmentation based region competition and the minimization of a specific energy function to detect and identify the runway edges from streaming video data. The resulting video-based runway position estimates are updated using a Kalman Filter, which can integrate other sensory information such as position and attitude angle estimates to allow a more robust tracking of the runway under turbulence. We illustrate the performance of the proposed lane detection and tracking scheme on various experimental UAV flights conducted by the Saudi Aerospace Research Center. Results show an accurate tracking of the runway edges during the landing phase under various lighting conditions. Also, it suggests that such positional estimates would greatly improve the positional accuracy of the UAV during takeoff and landing phases. The robustness of the proposed algorithm is further validated using Hardware in the Loop simulations with diverse takeoff and landing videos generated using a commercial flight simulator.

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

Tracking a convoy of multiple targets using acoustic sensor data

Science.gov (United States)

Damarla, T. R.

2003-08-01

In this paper we present an algorithm to track a convoy of several targets in a scene using acoustic sensor array data. The tracking algorithm is based on template of the direction of arrival (DOA) angles for the leading target. Often the first target is the closest target to the sensor array and hence the loudest with good signal to noise ratio. Several steps were used to generate a template of the DOA angle for the leading target, namely, (a) the angle at the present instant should be close to the angle at the previous instant and (b) the angle at the present instant should be within error bounds of the predicted value based on the previous values. Once the template of the DOA angles of the leading target is developed, it is used to predict the DOA angle tracks of the remaining targets. In order to generate the tracks for the remaining targets, a track is established if the angles correspond to the initial track values of the first target. Second the time delay between the first track and the remaining tracks are estimated at the highest correlation points between the first track and the remaining tracks. As the vehicles move at different speeds the tracks either compress or expand depending on whether a target is moving fast or slow compared to the first target. The expansion and compression ratios are estimated and used to estimate the predicted DOA angle values of the remaining targets. Based on these predicted DOA angles of the remaining targets the DOA angles obtained from the MVDR or Incoherent MUSIC will be appropriately assigned to proper tracks. Several other rules were developed to avoid mixing the tracks. The algorithm is tested on data collected at Aberdeen Proving Ground with a convoy of 3, 4 and 5 vehicles. Some of the vehicles are tracked and some are wheeled vehicles. The tracking algorithm results are found to be good. The results will be presented at the conference and in the paper.

Roll-to-Roll Screen Printed Radio Frequency Identification Transponder Antennas for Vehicle Tracking Systems

Science.gov (United States)

Zichner, Ralf; Baumann, Reinhard R.

2013-05-01

Vehicle tracking systems based on ultra high frequency (UHF) radio frequency identification (RFID) technology are already introduced to control the access to car parks and corporate premises. For this field of application so-called Windshield RFID transponder labels are used, which are applied to the inside of the windshield. State of the art for manufacturing these transponder antennas is the traditional lithography/etching approach. Furthermore the performance of these transponders is limited to a reading distance of approximately 5 m which results in car speed limit of 5 km/h for identification. However, to achieve improved performance compared to existing all-purpose transponders and a dramatic cost reduction, an optimized antenna design is needed which takes into account the special dielectric and in particular metallic car environment of the tag and an roll-to-roll (R2R) printing manufacturing process. In this paper we focus on the development of a customized UHF RFID transponder antenna design, which is adopted for vehicle geometry as well as R2R screen printing manufacturing processes.

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.

Satellite and ground-based sensors for the Urban Heat Island analysis in the city of Rome

DEFF Research Database (Denmark)

Fabrizi, Roberto; Bonafoni, Stefania; Biondi, Riccardo

2010-01-01

In this work, the trend of the Urban Heat Island (UHI) of Rome is analyzed by both ground-based weather stations and a satellite-based infrared sensor. First, we have developed a suitable algorithm employing satellite brightness temperatures for the estimation of the air temperature belonging...... and nighttime scenes taken between 2003 and 2006 have been processed. Analysis of the Canopy Layer Heat Island (CLHI) during summer months reveals a mean growth in magnitude of 3-4 K during nighttime and a negative or almost zero CLHI intensity during daytime, confirmed by the weather stations. © 2010...... by the authors; licensee MDPI, Basel, Switzerland. Keyword: Thermal pollution,Summer months,Advanced-along track scanning radiometers,Urban heat island,Remote sensing,Canopy layer,Atmospheric temperature,Ground based sensors,Weather information services,Satellite remote sensing,Infra-red sensor,Weather stations...

High-resolution sensing for precision agriculture: from Earth-observing satellites to unmanned aerial vehicles

Science.gov (United States)

McCabe, Matthew F.; Houborg, Rasmus; Lucieer, Arko

2016-10-01

With global population projected to approach 9 billion by 2050, it has been estimated that a 40% increase in cereal production will be required to satisfy the worlds growing nutritional demands. Any such increases in agricultural productivity are likely to occur within a system that has limited room for growth and in a world with a climate that is different from that of today. Fundamental to achieving food and water security, is the capacity to monitor the health and condition of agricultural systems. While space-agency based satellites have provided the backbone for earth observation over the last few decades, many developments in the field of high-resolution earth observation have been advanced by the commercial sector. These advances relate not just to technological developments in the use of unmanned aerial vehicles (UAVs), but also the advent of nano-satellite constellations that offer a radical shift in the way earth observations are now being retrieved. Such technologies present opportunities for improving our description of the water, energy and carbon cycles. Efforts towards developing new observational techniques and interpretative frameworks are required to provide the tools and information needed to improve the management and security of agricultural and related sectors. These developments are one of the surest ways to better manage, protect and preserve national food and water resources. Here we review the capabilities of recently deployed satellite systems and UAVs and examine their potential for application in precision agriculture.

High-resolution sensing for precision agriculture: from Earth-observing satellites to unmanned aerial vehicles

KAUST Repository

McCabe, Matthew

2016-10-25

With global population projected to approach 9 billion by 2050, it has been estimated that a 40% increase in cereal production will be required to satisfy the worlds growing nutritional demands. Any such increases in agricultural productivity are likely to occur within a system that has limited room for growth and in a world with a climate that is different from that of today. Fundamental to achieving food and water security, is the capacity to monitor the health and condition of agricultural systems. While space-Agency based satellites have provided the backbone for earth observation over the last few decades, many developments in the field of high-resolution earth observation have been advanced by the commercial sector. These advances relate not just to technological developments in the use of unmanned aerial vehicles (UAVs), but also the advent of nano-satellite constellations that offer a radical shift in the way earth observations are now being retrieved. Such technologies present opportunities for improving our description of the water, energy and carbon cycles. Efforts towards developing new observational techniques and interpretative frameworks are required to provide the tools and information needed to improve the management and security of agricultural and related sectors. These developments are one of the surest ways to better manage, protect and preserve national food and water resources. Here we review the capabilities of recently deployed satellite systems and UAVs and examine their potential for application in precision agriculture.

The methods for diagnostic of the technical condition of vehicles employing high precise satellite data

Directory of Open Access Journals (Sweden)

Anatoliy KULIK

2014-03-01

Full Text Available The paper presents a methodology for diagnostic of the technical condition of vehicle. The high accuracy of the actual trajectory of the transport aggregate (TA is provided by the use of local differential mode of global navigation satellite system (GNSS. Comparing the real and rational trajectories will determine the kinematic and dynamic characteristics of the car.

Mobility management in satellite networks

Science.gov (United States)

Johanson, Gary A.

1995-01-01

This paper addresses the methods used or proposed for use in multi-beam and/or multi-satellite networks designed to provide Mobile Satellite Services (MSS). Specific topics include beam crossover in the North American Mobile Satellite (MSAT) system as well as registration and live call hand-off for a multi-regional geosynchronous (GEO) satellite based system and a global coverage Low Earth Orbiting (LEO) system. In the MSAT system, the individual satellite beams cover very large geographic areas so the need for live call hand-off was not anticipated. This paper discusses the methods used to keep track of the beam location of the users so that incoming call announcements or other messages may be directed to them. Proposed new GEO systems with large numbers of beams will provide much smaller geographic coverage in individual beams and thus the need arises to keep track of the user's location as well as to provide live call hand-off as the user traverses from beam to beam. This situation also occurs in proposed LEO systems where the problems are worsened by the need for satellite to satellite hand-off as well as beam to beam hand-off within a single satellite. The paper discusses methods to accomplish these handoffs and proposes system architectures to address the various hand-off scenarios.

Multi-vehicle detection with identity awareness using cascade Adaboost and Adaptive Kalman filter for driver assistant system.

Science.gov (United States)

Wang, Baofeng; Qi, Zhiquan; Chen, Sizhong; Liu, Zhaodu; Ma, Guocheng

2017-01-01

Vision-based vehicle detection is an important issue for advanced driver assistance systems. In this paper, we presented an improved multi-vehicle detection and tracking method using cascade Adaboost and Adaptive Kalman filter(AKF) with target identity awareness. A cascade Adaboost classifier using Haar-like features was built for vehicle detection, followed by a more comprehensive verification process which could refine the vehicle hypothesis in terms of both location and dimension. In vehicle tracking, each vehicle was tracked with independent identity by an Adaptive Kalman filter in collaboration with a data association approach. The AKF adaptively adjusted the measurement and process noise covariance through on-line stochastic modelling to compensate the dynamics changes. The data association correctly assigned different detections with tracks using global nearest neighbour(GNN) algorithm while considering the local validation. During tracking, a temporal context based track management was proposed to decide whether to initiate, maintain or terminate the tracks of different objects, thus suppressing the sparse false alarms and compensating the temporary detection failures. Finally, the proposed method was tested on various challenging real roads, and the experimental results showed that the vehicle detection performance was greatly improved with higher accuracy and robustness.

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.

Precise orbit determination for BDS3 experimental satellites using iGMAS and MGEX tracking networks

Science.gov (United States)

Li, Xingxing; Yuan, Yongqiang; Zhu, Yiting; Huang, Jiande; Wu, Jiaqi; Xiong, Yun; Zhang, Xiaohong; Li, Xin

2018-04-01

In this contribution, we focus on the precise orbit determination (POD) for BDS3 experimental satellites with the international GNSS Monitoring and Assessment System (iGMAS) and Multi-GNSS Experiment (MGEX) tracking networks. The datasets of DOY (day of year) 001-230 in 2017 are analyzed with different processing strategies. By comparing receiver clock biases and receiver B1I-B3I DCBs, it is confirmed that there is no obvious systematic bias between experimental BDS3 and BDS2 in the common B1I and B3I signals, which indicates that experimental BDS3 and BDS2 can be treated as one system when performing combined POD. With iGMAS-only BDS3 stations, the 24-h overlap RMS of BDS3 + BDS2 + GPS combined POD is 24.3, 16.1 and 8.4 cm in along-track, cross-track and radial components, which is better than BDS3-only POD by 80-90% and better than BDS3+BDS2 combined POD by about 10%. With more stations (totally 20 stations from both iGMAS and MGEX) and the proper ambiguity resolution strategy (GEO ambiguities are float and BDS3 ambiguities are fixed), the performance of BDS3 POD can be further improved to 14.6, 7.9 and 3.7 cm, respectively, in along-track, cross-track and radial components, which is comparable to the performance of BDS2 POD. The 230-day SLR validations of C32, C33 and C34 show that the mean differences of - 3.48 , 7.81 and 8.19 cm can be achieved, while the STD is 13.35, 13.46 and 13.11 cm, respectively. Furthermore, the 230-day overlap comparisons reveal that C31 most likely still uses an orbit-normal mode and exhibits similar orbit modeling problems in orbit-normal periods as found in most of the BDS2 satellites.

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.

Vision based guidance and flight control in problems of aerial tracking

Science.gov (United States)

Stepanyan, Vahram

The use of visual sensors in providing the necessary information for the autonomous guidance and navigation of the unmanned-air vehicles (UAV) or micro-air vehicles (MAV) applications is inspired by biological systems and is motivated first of all by the reduction of the navigational sensor cost. Also, visual sensors can be more advantageous in military operations since they are difficult to detect. However, the design of a reliable guidance, navigation and control system for aerial vehicles based only on visual information has many unsolved problems, ranging from hardware/software development to pure control-theoretical issues, which are even more complicated when applied to the tracking of maneuvering unknown targets. This dissertation describes guidance law design and implementation algorithms for autonomous tracking of a flying target, when the information about the target's current position is obtained via a monocular camera mounted on the tracking UAV (follower). The visual information is related to the target's relative position in the follower's body frame via the target's apparent size, which is assumed to be constant, but otherwise unknown to the follower. The formulation of the relative dynamics in the inertial frame requires the knowledge of the follower's orientation angles, which are assumed to be known. No information is assumed to be available about the target's dynamics. The follower's objective is to maintain a desired relative position irrespective of the target's motion. Two types of guidance laws are designed and implemented in the dissertation. The first one is a smooth guidance law that guarantees asymptotic tracking of a target, the velocity of which is viewed as a time-varying disturbance, the change in magnitude of which has a bounded integral. The second one is a smooth approximation of a discontinuous guidance law that guarantees bounded tracking with adjustable bounds when the target's acceleration is viewed as a bounded but otherwise

77 FR 6949 - Tracking and Data Relay Satellite System (TDRSS) Rates for Non-U.S. Government Customers

Science.gov (United States)

2012-02-10

... Tracking and Data Relay Satellite System (TDRSS) Rates for Non- U.S. Government Customers AGENCY: National... customer flexibility, allowing more efficient use of the system. This notion was never implemented in the... commercial customers, as well as Arctic and Antarctic science programs. In this direct final rule, NASA is...

Real-time object tracking system based on field-programmable gate array and convolution neural network

Directory of Open Access Journals (Sweden)

Congyi Lyu

2016-12-01

Full Text Available Vision-based object tracking has lots of applications in robotics, like surveillance, navigation, motion capturing, and so on. However, the existing object tracking systems still suffer from the challenging problem of high computation consumption in the image processing algorithms. The problem can prevent current systems from being used in many robotic applications which have limitations of payload and power, for example, micro air vehicles. In these applications, the central processing unit- or graphics processing unit-based computers are not good choices due to the high weight and power consumption. To address the problem, this article proposed a real-time object tracking system based on field-programmable gate array, convolution neural network, and visual servo technology. The time-consuming image processing algorithms, such as distortion correction, color space convertor, and Sobel edge, Harris corner features detector, and convolution neural network were redesigned using the programmable gates in field-programmable gate array. Based on the field-programmable gate array-based image processing, an image-based visual servo controller was designed to drive a two degree of freedom manipulator to track the target in real time. Finally, experiments on the proposed system were performed to illustrate the effectiveness of the real-time object tracking system.

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 is...

A hybrid positioning strategy for vehicles in a tunnel based on RFID and in-vehicle sensors.

Science.gov (United States)

Song, Xiang; Li, Xu; Tang, Wencheng; Zhang, Weigong; Li, Bin

2014-12-05

Many intelligent transportation system applications require accurate, reliable, and continuous vehicle positioning. How to achieve such positioning performance in extended GPS-denied environments such as tunnels is the main challenge for land vehicles. This paper proposes a hybrid multi-sensor fusion strategy for vehicle positioning in tunnels. First, the preliminary positioning algorithm is developed. The Radio Frequency Identification (RFID) technology is introduced to achieve preliminary positioning in the tunnel. The received signal strength (RSS) is used as an indicator to calculate the distances between the RFID tags and reader, and then a Least Mean Square (LMS) federated filter is designed to provide the preliminary position information for subsequent global fusion. Further, to improve the positioning performance in the tunnel, an interactive multiple model (IMM)-based global fusion algorithm is developed to fuse the data from preliminary positioning results and low-cost in-vehicle sensors, such as electronic compasses and wheel speed sensors. In the actual implementation of IMM, the strong tracking extended Kalman filter (STEKF) algorithm is designed to replace the conventional extended Kalman filter (EKF) to achieve model individual filtering. Finally, the proposed strategy is evaluated through experiments. The results validate the feasibility and effectiveness of the proposed strategy.

A Hybrid Positioning Strategy for Vehicles in a Tunnel Based on RFID and In-Vehicle Sensors

Directory of Open Access Journals (Sweden)

Xiang Song

2014-12-01

Full Text Available Many intelligent transportation system applications require accurate, reliable, and continuous vehicle positioning. How to achieve such positioning performance in extended GPS-denied environments such as tunnels is the main challenge for land vehicles. This paper proposes a hybrid multi-sensor fusion strategy for vehicle positioning in tunnels. First, the preliminary positioning algorithm is developed. The Radio Frequency Identification (RFID technology is introduced to achieve preliminary positioning in the tunnel. The received signal strength (RSS is used as an indicator to calculate the distances between the RFID tags and reader, and then a Least Mean Square (LMS federated filter is designed to provide the preliminary position information for subsequent global fusion. Further, to improve the positioning performance in the tunnel, an interactive multiple model (IMM-based global fusion algorithm is developed to fuse the data from preliminary positioning results and low-cost in-vehicle sensors, such as electronic compasses and wheel speed sensors. In the actual implementation of IMM, the strong tracking extended Kalman filter (STEKF algorithm is designed to replace the conventional extended Kalman filter (EKF to achieve model individual filtering. Finally, the proposed strategy is evaluated through experiments. The results validate the feasibility and effectiveness of the proposed strategy.

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.

Elastomers for Tracked Vehicles: 1980-1997 Program to Improve Durability of Rubber Tank Pads for Army Tracked Vehicles

Science.gov (United States)

2015-06-01

elastomeric compound coded NBR -12 was developed. This compound was based on a highly saturated nitrile rubber or hydrogenated acrylonitrile-butadiene...at Fort Belvoir, VA, produced a patented rubber formulation ( NBR -12) based on hydrogenated nitrile rubber (HNBR)1,2 with a novel curing and filler...performance vehicles. • Acrylonitrile butadiene or nitrile rubber ( NBR )10: NBR is the generic name given to emulsion polymerized copolymers of

Improving BeiDou precise orbit determination using observations of onboard MEO satellite receivers

Science.gov (United States)

Ge, Haibo; Li, Bofeng; Ge, Maorong; Shen, Yunzhong; Schuh, Harald

2017-12-01

In recent years, the precise orbit determination (POD) of the regional Chinese BeiDou Navigation Satellite System (BDS) has been a hot spot because of its special constellation consisting of five geostationary earth orbit (GEO) satellites and five inclined geosynchronous satellite orbit (IGSO) satellites besides four medium earth orbit (MEO) satellites since the end of 2012. GEO and IGSO satellites play an important role in regional BDS applications. However, this brings a great challenge to the POD, especially for the GEO satellites due to their geostationary orbiting. Though a number of studies have been carried out to improve the POD performance of GEO satellites, the result is still much worse than that of IGSO and MEO, particularly in the along-track direction. The major reason is that the geostationary characteristic of a GEO satellite results in a bad geometry with respect to the ground tracking network. In order to improve the tracking geometry of the GEO satellites, a possible strategy is to mount global navigation satellite system (GNSS) receivers on MEO satellites to collect the signals from GEO/IGSO GNSS satellites so as that these observations can be used to improve GEO/IGSO POD. We extended our POD software package to simulate all the related observations and to assimilate the MEO-onboard GNSS observations in orbit determination. Based on GPS and BDS constellations, simulated studies are undertaken for various tracking scenarios. The impact of the onboard GNSS observations is investigated carefully and presented in detail. The results show that MEO-onboard observations can significantly improve the orbit precision of GEO satellites from metres to decimetres, especially in the along-track direction. The POD results of IGSO satellites also benefit from the MEO-onboard data and the precision can be improved by more than 50% in 3D direction.

Satellite and acoustic tracking device

KAUST Repository

Berumen, Michael L.

2014-02-20

The present invention relates a method and device for tracking movements of marine animals or objects in large bodies of water and across significant distances. The method and device can track an acoustic transmitter attached to an animal or object beneath the ocean surface by employing an unmanned surface vessel equipped with a hydrophone array and GPS receiver.

Satellite and acoustic tracking device

KAUST Repository

Berumen, Michael L.; De la Torre, Pedro

2014-01-01

The present invention relates a method and device for tracking movements of marine animals or objects in large bodies of water and across significant distances. The method and device can track an acoustic transmitter attached to an animal or object beneath the ocean surface by employing an unmanned surface vessel equipped with a hydrophone array and GPS receiver.

Multi-vehicle detection with identity awareness using cascade Adaboost and Adaptive Kalman filter for driver assistant system.

Directory of Open Access Journals (Sweden)

Baofeng Wang

Full Text Available Vision-based vehicle detection is an important issue for advanced driver assistance systems. In this paper, we presented an improved multi-vehicle detection and tracking method using cascade Adaboost and Adaptive Kalman filter(AKF with target identity awareness. A cascade Adaboost classifier using Haar-like features was built for vehicle detection, followed by a more comprehensive verification process which could refine the vehicle hypothesis in terms of both location and dimension. In vehicle tracking, each vehicle was tracked with independent identity by an Adaptive Kalman filter in collaboration with a data association approach. The AKF adaptively adjusted the measurement and process noise covariance through on-line stochastic modelling to compensate the dynamics changes. The data association correctly assigned different detections with tracks using global nearest neighbour(GNN algorithm while considering the local validation. During tracking, a temporal context based track management was proposed to decide whether to initiate, maintain or terminate the tracks of different objects, thus suppressing the sparse false alarms and compensating the temporary detection failures. Finally, the proposed method was tested on various challenging real roads, and the experimental results showed that the vehicle detection performance was greatly improved with higher accuracy and robustness.

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.

Visual Odometry and Place Recognition Fusion for Vehicle Position Tracking in Urban Environments.

Science.gov (United States)

Ouerghi, Safa; Boutteau, Rémi; Savatier, Xavier; Tlili, Fethi

2018-03-22

In this paper, we address the problem of vehicle localization in urban environments. We rely on visual odometry, calculating the incremental motion, to track the position of the vehicle and on place recognition to correct the accumulated drift of visual odometry, whenever a location is recognized. The algorithm used as a place recognition module is SeqSLAM, addressing challenging environments and achieving quite remarkable results. Specifically, we perform the long-term navigation of a vehicle based on the fusion of visual odometry and SeqSLAM. The template library for this latter is created online using navigation information from the visual odometry module. That is, when a location is recognized, the corresponding information is used as an observation of the filter. The fusion is done using the EKF and the UKF, the well-known nonlinear state estimation methods, to assess the superior alternative. The algorithm is evaluated using the KITTI dataset and the results show the reduction of the navigation errors by loop-closure detection. The overall position error of visual odometery with SeqSLAM is 0.22% of the trajectory, which is much smaller than the navigation errors of visual odometery alone 0.45%. In addition, despite the superiority of the UKF in a variety of estimation problems, our results indicate that the UKF performs as efficiently as the EKF at the expense of an additional computational overhead. This leads to the conclusion that the EKF is a better choice for fusing visual odometry and SeqSlam in a long-term navigation context.

Containment control of networked autonomous underwater vehicles: A predictor-based neural DSC design.

Science.gov (United States)

Peng, Zhouhua; Wang, Dan; Wang, Wei; Liu, Lu

2015-11-01

This paper investigates the containment control problem of networked autonomous underwater vehicles in the presence of model uncertainty and unknown ocean disturbances. A predictor-based neural dynamic surface control design method is presented to develop the distributed adaptive containment controllers, under which the trajectories of follower vehicles nearly converge to the dynamic convex hull spanned by multiple reference trajectories over a directed network. Prediction errors, rather than tracking errors, are used to update the neural adaptation laws, which are independent of the tracking error dynamics, resulting in two time-scales to govern the entire system. The stability property of the closed-loop network is established via Lyapunov analysis, and transient property is quantified in terms of L2 norms of the derivatives of neural weights, which are shown to be smaller than the classical neural dynamic surface control approach. Comparative studies are given to show the substantial improvements of the proposed new method. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

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.

Sky-Hook Control and Kalman Filtering in Nonlinear Model of Tracked Vehicle Suspension System

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Jurkiewicz Andrzej

2017-09-01

Full Text Available The essence of the undertaken topic is application of the continuous sky-hook control strategy and the Extended Kalman Filter as the state observer in the 2S1 tracked vehicle suspension system. The half-car model of this suspension system consists of seven logarithmic spiral springs and two magnetorheological dampers which has been described by the Bingham model. The applied continuous sky-hook control strategy considers nonlinear stiffness characteristic of the logarithmic spiral springs. The control is determined on estimates generated by the Extended Kalman Filter. Improve of ride comfort is verified by comparing simulation results, under the same driving conditions, of controlled and passive vehicle suspension systems.

Multi-UAV Doppler Information Fusion for Target Tracking Based on Distributed High Degrees Information Filters

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Hamza Benzerrouk

2018-03-01

Full Text Available Multi-Unmanned Aerial Vehicle (UAV Doppler-based target tracking has not been widely investigated, specifically when using modern nonlinear information filters. A high-degree Gauss–Hermite information filter, as well as a seventh-degree cubature information filter (CIF, is developed to improve the fifth-degree and third-degree CIFs proposed in the most recent related literature. These algorithms are applied to maneuvering target tracking based on Radar Doppler range/range rate signals. To achieve this purpose, different measurement models such as range-only, range rate, and bearing-only tracking are used in the simulations. In this paper, the mobile sensor target tracking problem is addressed and solved by a higher-degree class of quadrature information filters (HQIFs. A centralized fusion architecture based on distributed information filtering is proposed, and yielded excellent results. Three high dynamic UAVs are simulated with synchronized Doppler measurement broadcasted in parallel channels to the control center for global information fusion. Interesting results are obtained, with the superiority of certain classes of higher-degree quadrature information filters.

Satellite Power Systems (SPS) concept definition study. Volume 5: Special emphasis studies. [rectenna and solar power satellite design studies

Science.gov (United States)

Hanley, G. M.

1980-01-01

Satellite configurations based on the Satellite Power System baseline requirements were analyzed and a preferred concept selected. A satellite construction base was defined, precursor operations incident to establishment of orbital support facilities identified, and the satellite construction sequence and procedures developed. Rectenna construction requirement were also addressed. Mass flow to orbit requirements were revised and traffic models established based on construction of 60 instead of 120 satellites. Analyses were conducted to determine satellite control, resources, manufacturing, and propellant requirements. The impact of the laser beam used for space-to-Earth power transmission upon the intervening atmosphere was examined as well as the inverse effect. The significant space environments and their effects on spacecraft components were investigated to define the design and operational limits imposed by the environments on an orbit transfer vehicle. The results show that LEO altitude 300 nmi and transfer orbit duration 6 months are preferrable.

Vision-based Vehicle Detection Survey

Directory of Open Access Journals (Sweden)

Alex David S

2016-03-01

Full Text Available Nowadays thousands of drivers and passengers were losing their lives every year on road accident, due to deadly crashes between more than one vehicle. There are number of many research focuses were dedicated to the development of intellectual driver assistance systems and autonomous vehicles over the past decade, which reduces the danger by monitoring the on-road environment. In particular, researchers attracted towards the on-road detection of vehicles in recent years. Different parameters have been analyzed in this paper which includes camera placement and the various applications of monocular vehicle detection, common features and common classification methods, motion- based approaches and nighttime vehicle detection and monocular pose estimation. Previous works on the vehicle detection listed based on camera poisons, feature based detection and motion based detection works and night time detection.

A trajectory tracking controller for an underwater hexapod vehicle.

Science.gov (United States)

Plamondon, N; Nahon, M

2009-09-01

This paper describes work done in the modeling and control of a low speed underwater vehicle that uses paddles instead of thrusters to move in the water. A review of previously modeled vehicles and of controller designs for underwater applications is presented. Then, a method to accurately predict the thrust produced by an oscillating flexible paddle is developed and validated. This is followed by the development of a method to determine the ideal paddle motion to produce a desired thrust. Several controllers are then developed and tested using a numerical simulation of the vehicle. We found that some model-based controllers could improve the performance of the system while others showed no benefit. Finally, we report results from experimental trials performed in an open water environment comparing the performance of the controllers. The experimental results showed that all the model-based controllers outperform the simple proportional-derivative controller. The controller giving the best performance was the model-based nonlinear controller. We also found that the vehicle was able to follow a change of a roll angle of 90 degrees in 0.7 s and to precisely follow a sinusoidal trajectory with a period of 6.28 s and an amplitude of 5 degrees.

A trajectory tracking controller for an underwater hexapod vehicle

International Nuclear Information System (INIS)

Plamondon, N; Nahon, M

2009-01-01

This paper describes work done in the modeling and control of a low speed underwater vehicle that uses paddles instead of thrusters to move in the water. A review of previously modeled vehicles and of controller designs for underwater applications is presented. Then, a method to accurately predict the thrust produced by an oscillating flexible paddle is developed and validated. This is followed by the development of a method to determine the ideal paddle motion to produce a desired thrust. Several controllers are then developed and tested using a numerical simulation of the vehicle. We found that some model-based controllers could improve the performance of the system while others showed no benefit. Finally, we report results from experimental trials performed in an open water environment comparing the performance of the controllers. The experimental results showed that all the model-based controllers outperform the simple proportional-derivative controller. The controller giving the best performance was the model-based nonlinear controller. We also found that the vehicle was able to follow a change of a roll angle of 90 deg. in 0.7 s and to precisely follow a sinusoidal trajectory with a period of 6.28 s and an amplitude of 5 deg.

Vehicle Reference Generator for Collision-Free Trajectories in Hazardous Maneuvers

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Cuauhtémoc Acosta Lúa

2018-01-01

Full Text Available This paper presents a reference generator for ground vehicles, based on potential fields adapted to the case of vehicular dynamics. The reference generator generates signals to be tracked by the vehicle, corresponding to a trajectory avoiding collisions with obstacles. This generator integrates artificial forces of potential fields of the object surrounding the vehicle. The reference generator is used with a controller to ensure the tracking of the accident-free reference. This approach can be used for vehicle autonomous driving or for active control of manned vehicles. Simulation results, presented for the autonomous driving, consider a scenario inspired by the so-called moose (or elk test, with the presence of other collaborative vehicles.

Performance analysis of an IMU-augmented GNSS tracking system on board the MAIUS-1 sounding rocket

Science.gov (United States)

Braun, Benjamin; Grillenberger, Andreas; Markgraf, Markus

2018-05-01

Satellite navigation receivers are adequate tracking sensors for range safety of both orbital launch vehicles and suborbital sounding rockets. Due to high accuracy and its low system complexity, satellite navigation is seen as well-suited supplement or replacement of conventional tracking systems like radar. Having the well-known shortcomings of satellite navigation like deliberate or unintentional interferences in mind, it is proposed to augment the satellite navigation receiver by an inertial measurement unit (IMU) to enhance continuity and availability of localization. The augmented receiver is thus enabled to output at least an inertial position solution in case of signal outages. In a previous study, it was shown by means of simulation using the example of Ariane 5 that the performance of a low-grade microelectromechanical IMU is sufficient to bridge expected outages of some ten seconds, and still meeting the range safety requirements in effect. In this publication, these theoretical findings shall be substantiated by real flight data that were recorded on MAIUS-1, a sounding rocket launched from Esrange, Sweden, in early 2017. The analysis reveals that the chosen representative of a microelectromechanical IMU is suitable to bridge outages of up to thirty seconds.

Robust Vehicle and Traffic Information Extraction for Highway Surveillance

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Yeh Chia-Hung

2005-01-01

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.

Operational Satellite-based Surface Oil Analyses (Invited)

Science.gov (United States)

Streett, D.; Warren, C.

2010-12-01

During the Deepwater Horizon spill, NOAA imagery analysts in the Satellite Analysis Branch (SAB) issued more than 300 near-real-time satellite-based oil spill analyses. These analyses were used by the oil spill response community for planning, issuing surface oil trajectories and tasking assets (e.g., oil containment booms, skimmers, overflights). SAB analysts used both Synthetic Aperture Radar (SAR) and high resolution visible/near IR multispectral satellite imagery as well as a variety of ancillary datasets. Satellite imagery used included ENVISAT ASAR (ESA), TerraSAR-X (DLR), Cosmo-Skymed (ASI), ALOS (JAXA), Radarsat (MDA), ENVISAT MERIS (ESA), SPOT (SPOT Image Corp.), Aster (NASA), MODIS (NASA), and AVHRR (NOAA). Ancillary datasets included ocean current information, wind information, location of natural oil seeps and a variety of in situ oil observations. The analyses were available as jpegs, pdfs, shapefiles and through Google, KML files and also available on a variety of websites including Geoplatform and ERMA. From the very first analysis issued just 5 hours after the rig sank through the final analysis issued in August, the complete archive is still publicly available on the NOAA/NESDIS website http://www.ssd.noaa.gov/PS/MPS/deepwater.html SAB personnel also served as the Deepwater Horizon International Disaster Charter Project Manager (at the official request of the USGS). The Project Manager’s primary responsibility was to acquire and oversee the processing and dissemination of satellite data generously donated by numerous private companies and nations in support of the oil spill response including some of the imagery described above. SAB has begun to address a number of goals that will improve our routine oil spill response as well as help assure that we are ready for the next spill of national significance. We hope to (1) secure a steady, abundant and timely stream of suitable satellite imagery even in the absence of large-scale emergencies such as

Defining management units for cetaceans by combining genetics, morphology, acoustics and satellite tracking

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Signe Sveegaard

2015-01-01

Full Text Available Managing animal units is essential in biological conservation and requires spatial and temporal identification of such units. Since even neighbouring populations often have different conservation status and face different levels of anthropogenic pressure, detailed knowledge of population structure, seasonal range and overlap with animals from neighbouring populations is required to manage each unit separately. Previous studies on genetic structure and morphologic separation suggests three distinct populations of harbour porpoises with limited geographic overlap in the North Sea (NS, the Belt Sea (BS and the Baltic Proper (BP region. In this study, we aim to identify a management unit for the BS population of harbour porpoises. We use Argos satellite data and genetics from biopsies of tagged harbour porpoises as well as acoustic data from 40 passive acoustic data loggers to determine management areas with the least overlap between populations and thus the least error when abundance and population status is estimated. Discriminant analysis of the satellite tracking data from the BS and NS populations showed that the best fit of the management unit border during the summer months was an east–west line from Denmark to Sweden at latitude 56.95°N. For the border between BS and BP, satellite tracking data indicate a sharp decline in population density at 13.5°E, with 90% of the locations being west of this line. This was supported by the acoustic data with the average daily detection rate being 27.5 times higher west of 13.5°E as compared to east of 13.5°E. By using this novel multidisciplinary approach, we defined a management unit for the BS harbour porpoise population. We recommend that these boundaries are used for future monitoring efforts of this population under the EU directives. The boundaries may also be used for conservation efforts during the summer months, while seasonal movements of harbour porpoises should be considered during

Centriolar satellites

DEFF Research Database (Denmark)

Tollenaere, Maxim A X; Mailand, Niels; Bekker-Jensen, Simon

2015-01-01

Centriolar satellites are small, microscopically visible granules that cluster around centrosomes. These structures, which contain numerous proteins directly involved in centrosome maintenance, ciliogenesis, and neurogenesis, have traditionally been viewed as vehicles for protein trafficking...... highlight newly discovered regulatory mechanisms targeting centriolar satellites and their functional status, and we discuss how defects in centriolar satellite components are intimately linked to a wide spectrum of human diseases....

Tracking control of air-breathing hypersonic vehicles with non-affine dynamics via improved neural back-stepping design.

Science.gov (United States)

Bu, Xiangwei; He, Guangjun; Wang, Ke

2018-04-01

This study considers the design of a new back-stepping control approach for air-breathing hypersonic vehicle (AHV) non-affine models via neural approximation. The AHV's non-affine dynamics is decomposed into velocity subsystem and altitude subsystem to be controlled separately, and robust adaptive tracking control laws are developed using improved back-stepping designs. Neural networks are applied to estimate the unknown non-affine dynamics, which guarantees the addressed controllers with satisfactory robustness against uncertainties. In comparison with the existing control methodologies, the special contributions are that the non-affine issue is handled by constructing two low-pass filters based on model transformations, and virtual controllers are treated as intermediate variables such that they aren't needed for back-stepping designs any more. Lyapunov techniques are employed to show the uniformly ultimately boundedness of all closed-loop signals. Finally, simulation results are presented to verify the tracking performance and superiorities of the investigated control strategy. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

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

Target Tracking in 3-D Using Estimation Based Nonlinear Control Laws for UAVs

Directory of Open Access Journals (Sweden)

Mousumi Ahmed

2016-02-01

Full Text Available This paper presents an estimation based backstepping like control law design for an Unmanned Aerial Vehicle (UAV to track a moving target in 3-D space. A ground-based sensor or an onboard seeker antenna provides range, azimuth angle, and elevation angle measurements to a chaser UAV that implements an extended Kalman filter (EKF to estimate the full state of the target. A nonlinear controller then utilizes this estimated target state and the chaser’s state to provide speed, flight path, and course/heading angle commands to the chaser UAV. Tracking performance with respect to measurement uncertainty is evaluated for three cases: (1 stationary white noise; (2 stationary colored noise and (3 non-stationary (range correlated white noise. Furthermore, in an effort to improve tracking performance, the measurement model is made more realistic by taking into consideration range-dependent uncertainties in the measurements, i.e., as the chaser closes in on the target, measurement uncertainties are reduced in the EKF, thus providing the UAV with more accurate control commands. Simulation results for these cases are shown to illustrate target state estimation and trajectory tracking performance.

Satellite and Ground-Based Sensors for the Urban Heat Island Analysis in the City of Rome

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Roberto Fabrizi

2010-05-01

Full Text Available In this work, the trend of the Urban Heat Island (UHI of Rome is analyzed by both ground-based weather stations and a satellite-based infrared sensor. First, we have developed a suitable algorithm employing satellite brightness temperatures for the estimation of the air temperature belonging to the layer of air closest to the surface. UHI spatial characteristics have been assessed using air temperatures measured by both weather stations and brightness temperature maps from the Advanced Along Track Scanning Radiometer (AATSR on board ENVISAT polar-orbiting satellite. In total, 634 daytime and nighttime scenes taken between 2003 and 2006 have been processed. Analysis of the Canopy Layer Heat Island (CLHI during summer months reveals a mean growth in magnitude of 3–4 K during nighttime and a negative or almost zero CLHI intensity during daytime, confirmed by the weather stations.

Fault-Tolerant Region-Based Control of an Underwater Vehicle with Kinematically Redundant Thrusters

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Zool H. Ismail

2014-01-01

Full Text Available This paper presents a new control approach for an underwater vehicle with a kinematically redundant thruster system. This control scheme is derived based on a fault-tolerant decomposition for thruster force allocation and a region control scheme for the tracking objective. Given a redundant thruster system, that is, six or more pairs of thrusters are used, the proposed redundancy resolution and region control scheme determine the number of thruster faults, as well as providing the reference thruster forces in order to keep the underwater vehicle within the desired region. The stability of the presented control law is proven in the sense of a Lyapunov function. Numerical simulations are performed with an omnidirectional underwater vehicle and the results of the proposed scheme illustrate the effectiveness in terms of optimizing the thruster forces.

Evolving earth-based and in-situ satellite network architectures for Mars communications and navigation support

Science.gov (United States)

Hastrup, Rolf; Weinberg, Aaron; McOmber, Robert

1991-09-01

Results of on-going studies to develop navigation/telecommunications network concepts to support future robotic and human missions to Mars are presented. The performance and connectivity improvements provided by the relay network will permit use of simpler, lower performance, and less costly telecom subsystems for the in-situ mission exploration elements. Orbiting relay satellites can serve as effective navigation aids by supporting earth-based tracking as well as providing Mars-centered radiometric data for mission elements approaching, in orbit, or on the surface of Mars. The relay satellite orbits may be selected to optimize navigation aid support and communication coverage for specific mission sets.

A performance study of unmanned aerial vehicle-based sensor networks under cyber attack

Science.gov (United States)

Puchaty, Ethan M.

In UAV-based sensor networks, an emerging area of interest is the performance of these networks under cyber attack. This study seeks to evaluate the performance trade-offs from a System-of-Systems (SoS) perspective between various UAV communications architecture options in the context two missions: tracking ballistic missiles and tracking insurgents. An agent-based discrete event simulation is used to model a sensor communication network consisting of UAVs, military communications satellites, ground relay stations, and a mission control center. Network susceptibility to cyber attack is modeled with probabilistic failures and induced data variability, with performance metrics focusing on information availability, latency, and trustworthiness. Results demonstrated that using UAVs as routers increased network availability with a minimal latency penalty and communications satellite networks were best for long distance operations. Redundancy in the number of links between communication nodes helped mitigate cyber-caused link failures and add robustness in cases of induced data variability by an adversary. However, when failures were not independent, redundancy and UAV routing were detrimental in some cases to network performance. Sensitivity studies indicated that long cyber-caused downtimes and increasing failure dependencies resulted in build-ups of failures and caused significant degradations in network performance.

Sensing and control for autonomous vehicles applications to land, water and air vehicles

CERN Document Server

Pettersen, Kristin; Nijmeijer, Henk

2017-01-01

This edited volume includes thoroughly collected on sensing and control for autonomous vehicles. Guidance, navigation and motion control systems for autonomous vehicles are increasingly important in land-based, marine and aerial operations. Autonomous underwater vehicles may be used for pipeline inspection, light intervention work, underwater survey and collection of oceanographic/biological data. Autonomous unmanned aerial systems can be used in a large number of applications such as inspection, monitoring, data collection, surveillance, etc. At present, vehicles operate with limited autonomy and a minimum of intelligence. There is a growing interest for cooperative and coordinated multi-vehicle systems, real-time re-planning, robust autonomous navigation systems and robust autonomous control of vehicles. Unmanned vehicles with high levels of autonomy may be used for safe and efficient collection of environmental data, for assimilation of climate and environmental models and to complement global satellite sy...

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

Model-Based Motion Tracking of Infants

DEFF Research Database (Denmark)

Olsen, Mikkel Damgaard; Herskind, Anna; Nielsen, Jens Bo

2014-01-01

Even though motion tracking is a widely used technique to analyze and measure human movements, only a few studies focus on motion tracking of infants. In recent years, a number of studies have emerged focusing on analyzing the motion pattern of infants, using computer vision. Most of these studies...... are based on 2D images, but few are based on 3D information. In this paper, we present a model-based approach for tracking infants in 3D. The study extends a novel study on graph-based motion tracking of infants and we show that the extension improves the tracking results. A 3D model is constructed...

Precise Object Tracking under Deformation

International Nuclear Information System (INIS)

Saad, M.H.

2010-01-01

The precise object tracking is an essential issue in several serious applications such as; robot vision, automated surveillance (civil and military), inspection, biomedical image analysis, video coding, motion segmentation, human-machine interface, visualization, medical imaging, traffic systems, satellite imaging etc. This framework focuses on the precise object tracking under deformation such as scaling, rotation, noise, blurring and change of illumination. This research is a trail to solve these serious problems in visual object tracking by which the quality of the overall system will be improved. Developing a three dimensional (3D) geometrical model to determine the current pose of an object and predict its future location based on FIR model learned by the OLS. This framework presents a robust ranging technique to track a visual target instead of the traditional expensive ranging sensors. The presented research work is applied to real video stream and achieved high precession results. xiiiThe precise object tracking is an essential issue in several serious applications such as; robot vision, automated surveillance (civil and military), inspection, biomedical image analysis, video coding, motion segmentation, human-machine interface, visualization, medical imaging, traffic systems, satellite imaging etc. This framework focuses on the precise object tracking under deformation such as scaling, rotation, noise, blurring and change of illumination. This research is a trail to solve these serious problems in visual object tracking by which the quality of the overall system will be improved. Developing a three dimensional (3D) geometrical model to determine the current pose of an object and predict its future location based on FIR model learned by the OLS. This framework presents a robust ranging technique to track a visual target instead of the traditional expensive ranging sensors. The presented research work is applied to real video stream and achieved high

Wheel Slip Control of Vehicle ABS Using Piezoactuator-Based Valve System

Directory of Open Access Journals (Sweden)

Juncheol Jeon

2014-04-01

Full Text Available This paper presents a novel piezoactuator-based valve for vehicle ABS. The piezoactuator located in one side of a rigid beam makes a displacement required to control the pressure at a flapper-nozzle of the pneumatic valve. In order to obtain the wide control range of the pressure, a pressure modulator comprised of dual-type cylinder and piston is proposed. The governing equation of the piezovalve system which consists of the proposed piezoactuator-based valve and the pressure modulator is obtained. The longitudinal vehicle dynamics and the wheel slip condition are then formulated. In order to evaluate the performance of the proposed piezovalve system from the viewpoint of the vehicle ABS, a sliding mode controller is designed for wheel slip control. The tracking control performances for the desired wheel slip rate are evaluated and the braking performances in terms of braking distance are then presented on different road conditions (dry asphalt, wet asphalt, and wet jennite. It is clearly shown that the desired wheel slip rate is well achieved and the braking distance and braking time can be significantly reduced by using the proposed piezovalve system associated with the slip rate controller.

Randomness-Based Scale-Chromatic Image Analysis for Interactive Mapping on Satellite-Roadway-Vehicle Network

Directory of Open Access Journals (Sweden)

Kohji Kamejima

2007-08-01

Full Text Available A new framework is presented for integrating satellite/avionics sensors with onboard vision to support information intensive maneuvering. Real time bindings of the bird's eye observation and the driver's view via GPS provides \\textit{as-is} basis for perception and decision. Randomness-based roadway pattern model is implemented by fractal coding scheme associating bird's eye and frontal views. The feasibility of the framework with resquirements for vison system is discussed through concept modeling and experimental studies.

Randomness-Based Scale-Chromatic Image Analysis for Interactive Mapping on Satellite-Roadway-Vehicle Network

Directory of Open Access Journals (Sweden)

Kohji Kamejima

2007-08-01

Full Text Available A new framework is presented for integrating satellite/avionics sensors with onboard vision to support information intensive maneuvering. Real time bindings of the bird's eye observation and the driver's view via GPS provides extit{as-is} basis for perception and decision. Randomness-based roadway pattern model is implemented by fractal coding scheme associating bird's eye and frontal views. The feasibility of the framework with resquirements for vison system is discussed through concept modeling and experimental studies.

Optical neural network system for pose determination of spinning satellites

Science.gov (United States)

Lee, Andrew; Casasent, David

1990-01-01

An optical neural network architecture and algorithm based on a Hopfield optimization network are presented for multitarget tracking. This tracker utilizes a neuron for every possible target track, and a quadratic energy function of neural activities which is minimized using gradient descent neural evolution. The neural net tracker is demonstrated as part of a system for determining position and orientation (pose) of spinning satellites with respect to a robotic spacecraft. The input to the system is time sequence video from a single camera. Novelty detection and filtering are utilized to locate and segment novel regions from the input images. The neural net multitarget tracker determines the correspondences (or tracks) of the novel regions as a function of time, and hence the paths of object (satellite) parts. The path traced out by a given part or region is approximately elliptical in image space, and the position, shape and orientation of the ellipse are functions of the satellite geometry and its pose. Having a geometric model of the satellite, and the elliptical path of a part in image space, the three-dimensional pose of the satellite is determined. Digital simulation results using this algorithm are presented for various satellite poses and lighting conditions.

Simulation of an advanced small aperture track system

Science.gov (United States)

Williams, Tommy J.; Crockett, Gregg A.; Brunson, Richard L.; Beatty, Brad; Zahirniak, Daniel R.; Deuto, Bernard G.

2001-08-01

Simulation development for EO Systems has progressed to new levels with the advent of COTS software tools such as Matlab/Simulink. These tools allow rapid reuse of simulation library routines. We have applied these tools to newly emerging Acquisition Tracking and Pointing (ATP) systems using many routines developed through a legacy to High Energy Laser programs such as AirBorne Laser, Space Based Laser, Tactical High Energy Laser, and The Air Force Research Laboratory projects associated with the Starfire Optical Range. The simulation architecture allows ease in testing various track algorithms under simulated scenes with the ability to rapidly vary system hardware parameters such as track sensor and track loop control systems. The atmospheric turbulence environment and associated optical distortion is simulated to high fidelity levels through the application of an atmospheric phase screen model to produce scintillation of the laser illuminator uplink. The particular ATP system simulated is a small transportable system for tracking satellites in a daytime environment and projects a low power laser and receives laser return from retro-reflector equipped satellites. The primary application of the ATP system (and therefore the simulation) is the determination of the illuminator beam profile, jitter, and scintillation of the low power laser at the satellite. The ATP system will serve as a test bed for satellite tracking in a high background during daytime. Of particular interest in this simulation is the ability to emulate the hardware modelogic within the simulation to test and refine system states and mode change decisions. Additionally, the simulation allows data from the hardware system tests to be imported into Matlab and to thereby drive the simulation or to be easily compared to simulation results.

Earth Observatory Satellite system definition study. Report no. 1: Orbit/launch vehicle tradeoff studies and recommendations

Science.gov (United States)

1974-01-01

A study was conducted to determine the recommended orbit for the Earth Observatory Satellite (EOS) Land Resources Mission. It was determined that a promising sun synchronous orbit is 366 nautical miles when using an instrument with a 100 nautical mile swath width. The orbit has a 17 day repeat cycle and a 14 nautical mile swath overlap. Payloads were developed for each mission, EOS A through F. For each mission, the lowest cost booster that was capable of lifting the payload to the EOS orbit was selected. The launch vehicles selected for the missions are identified on the basis of tradeoff studies and recommendations. The reliability aspects of the launch vehicles are analyzed.

STAR: FPGA-based software defined satellite transponder

Science.gov (United States)

Davalle, Daniele; Cassettari, Riccardo; Saponara, Sergio; Fanucci, Luca; Cucchi, Luca; Bigongiari, Franco; Errico, Walter

2013-05-01

This paper presents STAR, a flexible Telemetry, Tracking & Command (TT&C) transponder for Earth Observation (EO) small satellites, developed in collaboration with INTECS and SITAEL companies. With respect to state-of-the-art EO transponders, STAR includes the possibility of scientific data transfer thanks to the 40 Mbps downlink data-rate. This feature represents an important optimization in terms of hardware mass, which is important for EO small satellites. Furthermore, in-flight re-configurability of communication parameters via telecommand is important for in-orbit link optimization, which is especially useful for low orbit satellites where visibility can be as short as few hundreds of seconds. STAR exploits the principles of digital radio to minimize the analog section of the transceiver. 70MHz intermediate frequency (IF) is the interface with an external S/X band radio-frequency front-end. The system is composed of a dedicated configurable high-speed digital signal processing part, the Signal Processor (SP), described in technology-independent VHDL working with a clock frequency of 184.32MHz and a low speed control part, the Control Processor (CP), based on the 32-bit Gaisler LEON3 processor clocked at 32 MHz, with SpaceWire and CAN interfaces. The quantization parameters were fine-tailored to reach a trade-off between hardware complexity and implementation loss which is less than 0.5 dB at BER = 10-5 for the RX chain. The IF ports require 8-bit precision. The system prototype is fitted on the Xilinx Virtex 6 VLX75T-FF484 FPGA of which a space-qualified version has been announced. The total device occupation is 82 %.

Antarctic Iceberg Tracking Based on Time Series of Aqua AMSRE Microwave Brightness Temperature Measurements

Science.gov (United States)

Blonski, Slawomir; Peterson, Craig

2006-01-01

Observations of icebergs are identified as one of the requirements for the GEOSS (Global Earth Observation System of Systems) in the area of reducing loss of life and property from natural and human-induced disasters. However, iceberg observations are not included among targets in the GEOSS 10-Year Implementation Plan, and thus there is an unfulfilled need for iceberg detection and tracking in the near future. Large Antarctic icebergs have been tracked by the National Ice Center and by the academic community using a variety of satellite sensors including both passive and active microwave imagers, such as SSM/I (Special Sensor Microwave/Imager) deployed on the DMSP (Defense Meteorological Satellite Program) spacecraft. Improvements provided in recent years by NASA and non-NASA satellite radars, scatterometers, and radiometers resulted in an increased number of observed icebergs and even prompted a question: Is The Number of Antarctic Icebergs Really Increasing? [D.G. Long, J. Ballantyne, and C. Bertoia, Eos, Transactions of the American Geophysical Union 83 (42): 469 & 474, 15 October 2002]. AMSR-E (Advanced Microwave Scanning Radiometer for the Earth Observing System) represents an improvement over SSM/I, its predecessor. AMSR-E has more measurement channels and higher spatial resolution than SSM/I. For example, the instantaneous field of view of the AMSR-E s 89-GHz channels is 6 km by 4 km versus 16 km by 14 km for SSM/I s comparable 85-GHz channels. AMSR-E, deployed on the Aqua satellite, scans across a 1450-km swath and provides brightness temperature measurements with nearglobal coverage every one or two days. In polar regions, overlapping swaths generate coverage up to multiple times per day and allow for creation of image time series with high temporal resolution. Despite these advantages, only incidental usage of AMSR-E data for iceberg tracking has been reported so far, none in an operational environment. Therefore, an experiment was undertaken in the RPC

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

NOAA-L satellite arrives at Vandenberg AFB

Science.gov (United States)

2000-01-01

Outside the B16-10 spacecraft processing hangar at Vandenberg Air Force Base, Calif., a crated National Oceanic and Atmospheric Administration (NOAA-L) satellite is lowered to the ground before being moved inside. NOAA-L is part of the Polar-Orbiting Operational Environmental Satellite (POES) program that provides atmospheric measurements of temperature, humidity, ozone and cloud images, tracking weather patterns that affect the global weather and climate. The launch of the NOAA-L satellite is scheduled no earlier than Sept. 12 aboard a Lockheed Martin Titan II rocket. Polar bears from space: Assessing satellite imagery as a tool to track Arctic wildlife

Science.gov (United States)

Stapleton, Seth P.; LaRue, Michelle A.; Lecomte, Nicolas; Atkinson, Stephen N.; Garshelis, David L.; Porter, Claire; Atwood, Todd C.

2014-01-01

Development of efficient techniques for monitoring wildlife is a priority in the Arctic, where the impacts of climate change are acute and remoteness and logistical constraints hinder access. We evaluated high resolution satellite imagery as a tool to track the distribution and abundance of polar bears. We examined satellite images of a small island in Foxe Basin, Canada, occupied by a high density of bears during the summer ice-free season. Bears were distinguished from other light-colored spots by comparing images collected on different dates. A sample of ground-truthed points demonstrated that we accurately classified bears. Independent observers reviewed images and a population estimate was obtained using mark- recapture models. This estimate (N: 94; 95% Confidence Interval: 92-105) was remarkably similar to an abundance estimate derived from a line transect aerial survey conducted a few days earlier (N: 102; 95% CI: 69-152). Our findings suggest that satellite imagery is a promising tool for monitoring polar bears on land, with implications for use with other Arctic wildlife. Large scale applications may require development of automated detection processes to expedite review and analysis. Future research should assess the utility of multi-spectral imagery and examine sites with different environmental characteristics.

Polar bears from space: assessing satellite imagery as a tool to track Arctic wildlife.

Directory of Open Access Journals (Sweden)

Seth Stapleton

Full Text Available Development of efficient techniques for monitoring wildlife is a priority in the Arctic, where the impacts of climate change are acute and remoteness and logistical constraints hinder access. We evaluated high resolution satellite imagery as a tool to track the distribution and abundance of polar bears. We examined satellite images of a small island in Foxe Basin, Canada, occupied by a high density of bears during the summer ice-free season. Bears were distinguished from other light-colored spots by comparing images collected on different dates. A sample of ground-truthed points demonstrated that we accurately classified bears. Independent observers reviewed images and a population estimate was obtained using mark-recapture models. This estimate (N: 94; 95% Confidence Interval: 92-105 was remarkably similar to an abundance estimate derived from a line transect aerial survey conducted a few days earlier (N: 102; 95% CI: 69-152. Our findings suggest that satellite imagery is a promising tool for monitoring polar bears on land, with implications for use with other Arctic wildlife. Large scale applications may require development of automated detection processes to expedite review and analysis. Future research should assess the utility of multi-spectral imagery and examine sites with different environmental characteristics.

Polar bears from space: assessing satellite imagery as a tool to track Arctic wildlife.

Science.gov (United States)

Stapleton, Seth; LaRue, Michelle; Lecomte, Nicolas; Atkinson, Stephen; Garshelis, David; Porter, Claire; Atwood, Todd

2014-01-01

Development of efficient techniques for monitoring wildlife is a priority in the Arctic, where the impacts of climate change are acute and remoteness and logistical constraints hinder access. We evaluated high resolution satellite imagery as a tool to track the distribution and abundance of polar bears. We examined satellite images of a small island in Foxe Basin, Canada, occupied by a high density of bears during the summer ice-free season. Bears were distinguished from other light-colored spots by comparing images collected on different dates. A sample of ground-truthed points demonstrated that we accurately classified bears. Independent observers reviewed images and a population estimate was obtained using mark-recapture models. This estimate (N: 94; 95% Confidence Interval: 92-105) was remarkably similar to an abundance estimate derived from a line transect aerial survey conducted a few days earlier (N: 102; 95% CI: 69-152). Our findings suggest that satellite imagery is a promising tool for monitoring polar bears on land, with implications for use with other Arctic wildlife. Large scale applications may require development of automated detection processes to expedite review and analysis. Future research should assess the utility of multi-spectral imagery and examine sites with different environmental characteristics.

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...

Effective star tracking method based on optical flow analysis for star trackers.

Science.gov (United States)

Sun, Ting; Xing, Fei; Wang, Xiaochu; Li, Jin; Wei, Minsong; You, Zheng

2016-12-20

Benefiting from rapid development of imaging sensor technology, modern optical technology, and a high-speed computing chip, the star tracker's accuracy, dynamic performance, and update rate have been greatly improved with low power consumption and miniature size. The star tracker is currently one of the most competitive attitude measurement sensors. However, due to restrictions of the optical imaging system, difficulties still exist in moving star spot detection and star tracking when in special motion conditions. An effective star tracking method based on optical flow analysis for star trackers is proposed in this paper. Spot-based optical flow, based on a gray gradient between two adjacent star images, is analyzed to distinguish the star spot region and obtain an accurate star spot position so that the star tracking can keep continuous under high dynamic conditions. The obtained star vectors and extended Kalman filter (EKF) are then combined to conduct an angular velocity estimation to ensure region prediction of the star spot; this can be combined with the optical flow analysis result. Experiment results show that the method proposed in this paper has advantages in conditions of large angular velocity and large angular acceleration, despite the presence of noise. Higher functional density and better performance can be achieved; thus, the star tracker can be more widely applied in small satellites, remote sensing, and other complex space missions.

Study on Two-segment Electric-mechanical Composite Braking Strategy of Tracked Vehicle Hybrid Transmission System

OpenAIRE

Ma, Tian; Gai, Jiangtao; Ma, Xiaofeng

2010-01-01

In order to lighten abrasion of braking system of hybrid electric tracked vehicle, according to characteristic of hybrid electric transmission, electric-mechanical composite braking method was proposed. By means of analyzing performance of electric braking and mechanical braking and three-segment composite braking strategy, two-segment electric-mechanical composite braking strategy was put forward in this paper. Simulation results of Matlab/Simulink indicated that the two-segment electric-mec...

Future Satellite Gravimetry and Earth Dynamics

CERN Document Server

Flury, Jakob

2005-01-01

Currently, a first generation of dedicated satellite missions for the precise mapping of the Earth’s gravity field is in orbit (CHAMP, GRACE, and soon GOCE). The gravity data from these satellite missions provide us with very new information on the dynamics of planet Earth. In particular, on the mass distribution in the Earth’s interior, the entire water cycle (ocean circulation, ice mass balance, continental water masses, and atmosphere), and on changes in the mass distribution. The results are fascinating, but still rough with respect to spatial and temporal resolution. Technical progress in satellite-to-satellite tracking and in gravity gradiometry will allow more detailed results in the future. In this special issue, Earth scientists develop visions of future applications based on follow-on high-precision satellite gravimetry missions.

Automated Vehicle Monitoring System

OpenAIRE

Wibowo, Agustinus Deddy Arief; Heriansyah, Rudi

2014-01-01

An automated vehicle monitoring system is proposed in this paper. The surveillance system is based on image processing techniques such as background subtraction, colour balancing, chain code based shape detection, and blob. The proposed system will detect any human's head as appeared at the side mirrors. The detected head will be tracked and recorded for further action.

Tracking Control Based on Control Allocation with an Innovative Control Effector Aircraft Application

Directory of Open Access Journals (Sweden)

Chaoyang Dong

2016-01-01

Full Text Available This paper proposes a control allocation method for the tracking control problem of a class of morphing aircraft with special actuators which are different from the conventional actuation surfaces. This design of actuators can bring about some potential advantages to the flight vehicles; however, due to the integral constraints, the desired control cannot be performed accurately; therefore, it leads to undesirable tracking errors, so influencing the performance of the system. Because the system could be control allocated, based on the designed cost function that describes the tracking errors, the cuckoo search algorithm (CSA is introduced to search for the optimum solution within the calculated actuator execution commands that are equivalent to the desired commands. Several improvement measures are proposed for boosting the efficiency of the CSA and ensuring reasonable solutions. Simulation results show that the proposed control allocation method is necessary and effective, and the improvement measures are helpful in obtaining the optimum solution.

Ultra-Wideband Tracking System Design for Relative Navigation

Science.gov (United States)

Ni, Jianjun David; Arndt, Dickey; Bgo, Phong; Dekome, Kent; Dusl, John

2011-01-01

This presentation briefly discusses a design effort for a prototype ultra-wideband (UWB) time-difference-of-arrival (TDOA) tracking system that is currently under development at NASA Johnson Space Center (JSC). The system is being designed for use in localization and navigation of a rover in a GPS deprived environment for surface missions. In one application enabled by the UWB tracking, a robotic vehicle carrying equipments can autonomously follow a crewed rover from work site to work site such that resources can be carried from one landing mission to the next thereby saving up-mass. The UWB Systems Group at JSC has developed a UWB TDOA High Resolution Proximity Tracking System which can achieve sub-inch tracking accuracy of a target within the radius of the tracking baseline [1]. By extending the tracking capability beyond the radius of the tracking baseline, a tracking system is being designed to enable relative navigation between two vehicles for surface missions. A prototype UWB TDOA tracking system has been designed, implemented, tested, and proven feasible for relative navigation of robotic vehicles. Future work includes testing the system with the application code to increase the tracking update rate and evaluating the linear tracking baseline to improve the flexibility of antenna mounting on the following vehicle.

Small Orbital Stereo Tracking Camera Technology Development

Science.gov (United States)

Gagliano, L.; Bryan, T.; MacLeod, T.

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 NASAs 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.

Real-Time Implementation of an Asynchronous Vision-Based Target Tracking System for an Unmanned Aerial Vehicle

Science.gov (United States)

2007-06-01

Chin Khoon Quek. “Vision Based Control and Target Range Estimation for Small Unmanned Aerial Vehicle.” Master’s Thesis, Naval Postgraduate School...December 2005. [6] Kwee Chye Yap. “Incorporating Target Mensuration System for Target Motion Estimation Along a Road Using Asynchronous Filter

Determining origin in a migratory marine vertebrate: a novel method to integrate stable isotopes and satellite tracking

Science.gov (United States)

Vander Zanden, Hannah B.; Tucker, Anton D.; Hart, Kristen M.; Lamont, Margaret M.; Fujisaki, Ikuko; Addison, David S.; Mansfield, Katherine L.; Phillips, Katrina F.; Wunder, Michael B.; Bowen, Gabriel J.; Pajuelo, Mariela; Bolten, Alan B.; Bjorndal, Karen A.

2015-01-01

Stable isotope analysis is a useful tool to track animal movements in both terrestrial and marine environments. These intrinsic markers are assimilated through the diet and may exhibit spatial gradients as a result of biogeochemical processes at the base of the food web. In the marine environment, maps to predict the spatial distribution of stable isotopes are limited, and thus determining geographic origin has been reliant upon integrating satellite telemetry and stable isotope data. Migratory sea turtles regularly move between foraging and reproductive areas. Whereas most nesting populations can be easily accessed and regularly monitored, little is known about the demographic trends in foraging populations. The purpose of the present study was to examine migration patterns of loggerhead nesting aggregations in the Gulf of Mexico (GoM), where sea turtles have been historically understudied. Two methods of geographic assignment using stable isotope values in known-origin samples from satellite telemetry were compared: 1) a nominal approach through discriminant analysis and 2) a novel continuous-surface approach using bivariate carbon and nitrogen isoscapes (isotopic landscapes) developed for this study. Tissue samples for stable isotope analysis were obtained from 60 satellite-tracked individuals at five nesting beaches within the GoM. Both methodological approaches for assignment resulted in high accuracy of foraging area determination, though each has advantages and disadvantages. The nominal approach is more appropriate when defined boundaries are necessary, but up to 42% of the individuals could not be considered in this approach. All individuals can be included in the continuous-surface approach, and individual results can be aggregated to identify geographic hotspots of foraging area use, though the accuracy rate was lower than nominal assignment. The methodological validation provides a foundation for future sea turtle studies in the region to inexpensively

Sliding mode based trajectory linearization control for hypersonic reentry vehicle via extended disturbance observer.

Science.gov (United States)

Xingling, Shao; Honglun, Wang

2014-11-01

This paper proposes a novel hybrid control framework by combing observer-based sliding mode control (SMC) with trajectory linearization control (TLC) for hypersonic reentry vehicle (HRV) attitude tracking problem. First, fewer control consumption is achieved using nonlinear tracking differentiator (TD) in the attitude loop. Second, a novel SMC that employs extended disturbance observer (EDO) to counteract the effect of uncertainties using a new sliding surface which includes the estimation error is integrated to address the tracking error stabilization issues in the attitude and angular rate loop, respectively. In addition, new results associated with EDO are examined in terms of dynamic response and noise-tolerant performance, as well as estimation accuracy. The key feature of the proposed compound control approach is that chattering free tracking performance with high accuracy can be ensured for HRV in the presence of multiple uncertainties under control constraints. Based on finite time convergence stability theory, the stability of the resulting closed-loop system is well established. Also, comparisons and extensive simulation results are presented to demonstrate the effectiveness of the control strategy. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

X-Ray Pulsar Profile Recovery Based on Tracking-Differentiator

Directory of Open Access Journals (Sweden)

Dapeng Zhang

2016-01-01

Full Text Available The profile recovery is an important work in X-ray pulsar-based navigation. It is a key step for the analysis on the pulsar signal’s characteristic and the computing of time of arrival (TOA. This paper makes an argument for an algorithm based on the tracking-differentiator (TD to recover the profile from the low Signal-to-Noise Ratio (SNR signals. In the method, a TD filter with cascade structure is designed which has very low phase delay and amplitude distortion. In the simulation experiment, two typical pulsars (PSR B0531+21 and PSR B1937+21 are used to verify the algorithm’s performance. The simulation results show that the method satisfies the application requirements in the aspects of SNR and profile fidelity. By processing the data collected by the Rossi X-Ray Timing Explorer (RXTE satellite in space, similar results can also be achieved.

Steerability Analysis of Tracked Vehicles: Theory and User’s Guide for Computer Program TVSTEER

Science.gov (United States)

1986-08-01

Baladi , Donald E. Barnes, Rebecca P. BergerC oStructures Laboratory NDEPARTMENT OF THE ARMY ___ Waterways Experiment Station, Corps of Engineers . U P0 Box...Analysis of Tracked Vehicles: Theory and User’s Guide for Computer Program TVSTEER - 12 PERSONAL AUTHOR(S) Baladi , George Y., Barnes, Donald E...mathematical model was formulated by Drs. George Y. Baladi and Behzad Rohani. The logic and computer programming were accomplished by Dr. Baladi and

RFID-based vehicle positioning and its applications in connected vehicles.

Science.gov (United States)

Wang, Jianqiang; Ni, Daiheng; Li, Keqiang

2014-03-04

This paper proposed an RFID-based vehicle positioning approach to facilitate connected vehicles applications. When a vehicle passes over an RFID tag, the vehicle position is given by the accurate position stored in the tag. At locations without RFID coverage, the vehicle position is estimated from the most recent tag location using a kinematics integration algorithm till updates from the next tag. The accuracy of RFID positioning is verified empirically in two independent ways with one using radar and the other a photoelectric switch. The former is designed to verify whether the dynamic position obtained from RFID tags matches the position measured by radar that is regarded as accurate. The latter aims to verify whether the position estimated from the kinematics integration matches the position obtained from RFID tags. Both means supports the accuracy of RFID-based positioning. As a supplement to GPS which suffers from issues such as inaccuracy and loss of signal, RFID positioning is promising in facilitating connected vehicles applications. Two conceptual applications are provided here with one in vehicle operational control and the other in Level IV intersection control.

Integrated robust controller for vehicle path following

Energy Technology Data Exchange (ETDEWEB)

Mashadi, Behrooz; Ahmadizadeh, Pouyan, E-mail: p-ahmadizadeh@iust.ac.ir; Majidi, Majid, E-mail: m-majidi@iust.ac.ir [Iran University of Science and Technology, School of Automotive Engineering (Iran, Islamic Republic of); Mahmoodi-Kaleybar, Mehdi, E-mail: m-mahmoodi-k@iust.ac.ir [Iran University of Science and Technology, School of Mechanical Engineering (Iran, Islamic Republic of)

2015-02-15

The design of an integrated 4WS+DYC control system to guide a vehicle on a desired path is presented. The lateral dynamics of the path follower vehicle is formulated by considering important parameters. To reduce the effect of uncertainties in vehicle parameters, a robust controller is designed based on a μ-synthesis approach. Numerical simulations are performed using a nonlinear vehicle model in MATLAB environment in order to investigate the effectiveness of the designed controller. Results of simulations show that the controller has a profound ability to making the vehicle track the desired path in the presence of uncertainties.

Integrated robust controller for vehicle path following

International Nuclear Information System (INIS)

Mashadi, Behrooz; Ahmadizadeh, Pouyan; Majidi, Majid; Mahmoodi-Kaleybar, Mehdi

2015-01-01

The design of an integrated 4WS+DYC control system to guide a vehicle on a desired path is presented. The lateral dynamics of the path follower vehicle is formulated by considering important parameters. To reduce the effect of uncertainties in vehicle parameters, a robust controller is designed based on a μ-synthesis approach. Numerical simulations are performed using a nonlinear vehicle model in MATLAB environment in order to investigate the effectiveness of the designed controller. Results of simulations show that the controller has a profound ability to making the vehicle track the desired path in the presence of uncertainties

Automated vehicle for railway track fault detection

Science.gov (United States)

Bhushan, M.; Sujay, S.; Tushar, B.; Chitra, P.

2017-11-01

For the safety reasons, railroad tracks need to be inspected on a regular basis for detecting physical defects or design non compliances. Such track defects and non compliances, if not detected in a certain interval of time, may eventually lead to severe consequences such as train derailments. Inspection must happen twice weekly by a human inspector to maintain safety standards as there are hundreds and thousands of miles of railroad track. But in such type of manual inspection, there are many drawbacks that may result in the poor inspection of the track, due to which accidents may cause in future. So to avoid such errors and severe accidents, this automated system is designed.Such a concept would surely introduce automation in the field of inspection process of railway track and can help to avoid mishaps and severe accidents due to faults in the track.

Multisensor simultaneous vehicle tracking and shape estimation

NARCIS (Netherlands)

Elfring, J.; Appeldoorn, R.P.W.; Kwakkernaat, M.R.J.A.E.

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

Development of Bushing Compounds for Tracked Vehicles

Science.gov (United States)

1990-10-01

unwanted stepchild - part of called anti patented NBR -12 formulation the family (system), but devoid of needed indicated that service life could be...as Development and Engineering Center’s long. Bushings currently used in the M I track Rubber and Coated Fabrics Research Group assembly typically fail...formulations of should be improved. Numerous selected candidate natural rubber , propylene formulations-based on natural rubber , oxide, and silicone

Design of γ-ray vehicle patrol system based on GPS

International Nuclear Information System (INIS)

Zhang Wen; Li Changjin

2011-01-01

In order to detect the radiation in the surrounding environment of Nuclear facilities in a wide range, the γ-Ray vehicle patrol system based radiation on GPS and composed of γ-Ray detection terminal and PC is designed. The γ-Ray detection terminal uses controller ATmega128L as control core, detecting the radiation intensity of γ-Ray with G-M counter tube and getting the location with GPS module LR9548S, packing a data frame with γ-Ray radiation and location information according to the agreed protocol which will be sent to PC through UART interface; The PC can processes, display and analyze the data, backup to database Access2003, also can paint the measuring track and distributed picture of radiation intensity. The system can be equipped with a variety of vehicles for mobile patrol to use in the fields of searching radioactive sources, emergency monitoring and measurement of environmental radiation levels. (authors)

Optical Tracking Data Validation and Orbit Estimation for Sparse Observations of Satellites by the OWL-Net.

Science.gov (United States)

Choi, Jin; Jo, Jung Hyun; Yim, Hong-Suh; Choi, Eun-Jung; Cho, Sungki; Park, Jang-Hyun

2018-06-07

An Optical Wide-field patroL-Network (OWL-Net) has been developed for maintaining Korean low Earth orbit (LEO) satellites' orbital ephemeris. The OWL-Net consists of five optical tracking stations. Brightness signals of reflected sunlight of the targets were detected by a charged coupled device (CCD). A chopper system was adopted for fast astrometric data sampling, maximum 50 Hz, within a short observation time. The astrometric accuracy of the optical observation data was validated with precise orbital ephemeris such as Consolidated Prediction File (CPF) data and precise orbit determination result with onboard Global Positioning System (GPS) data from the target satellite. In the optical observation simulation of the OWL-Net for 2017, an average observation span for a single arc of 11 LEO observation targets was about 5 min, while an average optical observation separation time was 5 h. We estimated the position and velocity with an atmospheric drag coefficient of LEO observation targets using a sequential-batch orbit estimation technique after multi-arc batch orbit estimation. Post-fit residuals for the multi-arc batch orbit estimation and sequential-batch orbit estimation were analyzed for the optical measurements and reference orbit (CPF and GPS data). The post-fit residuals with reference show few tens-of-meters errors for in-track direction for multi-arc batch and sequential-batch orbit estimation results.

Water-Column Stratification Observed along an AUV-Tracked Isotherm

Science.gov (United States)

Zhang, Y.; Messié, M.; Ryan, J. P.; Kieft, B.; Stanway, M. J.; Hobson, B.; O'Reilly, T. C.; Raanan, B. Y.; Smith, J. M.; Chavez, F.

2016-02-01

Studies of marine physical, chemical and microbiological processes benefit from observing in a Lagrangian frame of reference, i.e. drifting with ambient water. Because these processes can be organized relative to specific density or temperature ranges, maintaining observing platforms within targeted environmental ranges is an important observing strategy. We have developed a novel method to enable a Tethys-class long-range autonomous underwater vehicle (AUV) (which has a propeller and a buoyancy engine) to track a target isotherm in buoyancy-controlled drift mode. In this mode, the vehicle shuts off its propeller and autonomously detects the isotherm and stays with it by actively controlling the vehicle's buoyancy. In the June 2015 CANON (Controlled, Agile, and Novel Observing Network) Experiment in Monterey Bay, California, AUV Makai tracked a target isotherm for 13 hours to study the coastal upwelling system. The tracked isotherm started from 33 m depth, shoaled to 10 m, and then deepened to 29 m. The thickness of the tracked isotherm layer (within 0.3°C error from the target temperature) increased over this duration, reflecting weakened stratification around the isotherm. During Makai's isotherm tracking, another long-range AUV, Daphne, acoustically tracked Makai on a circular yo-yo trajectory, measuring water-column profiles in Makai's vicinity. A wave glider also acoustically tracked Makai, providing sea surface measurements on the track. The presented method is a new approach for studying water-column stratification, but requires careful analysis of the temporal and spatial variations mingled in the vehicles' measurements. We will present a synthesis of the water column's stratification in relation to the upwelling conditions, based on the in situ measurements by the mobile platforms, as well as remote sensing and mooring data.

Noncoherent Doppler tracking: first flight results

Science.gov (United States)

DeBoy, Christopher C.; Robert Jensen, J.; Asher, Mark S.

2005-01-01

Noncoherent Doppler tracking has been devised as a means to achieve highly accurate, two-way Doppler measurements with a simple, transceiver-based communications system. This technique has been flown as an experiment on the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) spacecraft, (launched 7 December 2001), as the operational technique for Doppler tracking on CONTOUR, and is baselined on several future deep space missions at JHU/APL. This paper reports on initial results from a series of successful tests of this technique between the TIMED spacecraft and NASA ground stations in the Deep Space Network. It also examines the advantages that noncoherent Doppler tracking and a transceiver-based system may offer to small satellite systems, including reduced cost, mass, and power.

Three-Dimensional Planetary Surface Tracking Based on a Simple Ultra-Wideband Impulse-Radio Infrastructure

Science.gov (United States)

Barton, Richard J.; Ni, David; Ngo, Phong

2010-01-01

Several prototype ultra-wideband (UWB) impulse-radio (IR) tracking systems are currently under development at NASA Johnson Space Center (JSC). These systems are being studied for use in tracking of Lunar/Mars rovers and astronauts during early exploration missions when satellite navigation systems (such as GPS) are not available. To date, the systems that have been designed and tested are intended only for two-dimensional location and tracking, but these designs can all be extended to three-dimensional tracking with only minor modifications and increases in complexity. In this presentation, we will briefly review the design and performance of two of the current 2-D systems: one designed specifically for short-range, extremely high-precision tracking (approximately 1-2 cm resolution) and the other designed specifically for much longer range tracking with less stringent precision requirements (1-2 m resolution). We will then discuss a new multi-purpose system design based on a simple UWB-IR architecture that can be deployed easily on a planetary surface to support arbitrary three-dimensional localization and tracking applications. We will discuss utilization of this system as an infrastructure to provide both short-range and long-range tracking and analyze the localization performance of the system in several different configurations. We will give theoretical performance bounds for some canonical system configurations and compare these performance bounds with both numerical simulations of the system as well as actual experimental system performance evaluations.

Satellite-Based Precipitation Datasets

Science.gov (United States)

Munchak, S. J.; Huffman, G. J.

2017-12-01

Of the possible sources of precipitation data, those based on satellites provide the greatest spatial coverage. There is a wide selection of datasets, algorithms, and versions from which to choose, which can be confusing to non-specialists wishing to use the data. The International Precipitation Working Group (IPWG) maintains tables of the major publicly available, long-term, quasi-global precipitation data sets (http://www.isac.cnr.it/ ipwg/data/datasets.html), and this talk briefly reviews the various categories. As examples, NASA provides two sets of quasi-global precipitation data sets: the older Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) and current Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (GPM) mission (IMERG). Both provide near-real-time and post-real-time products that are uniformly gridded in space and time. The TMPA products are 3-hourly 0.25°x0.25° on the latitude band 50°N-S for about 16 years, while the IMERG products are half-hourly 0.1°x0.1° on 60°N-S for over 3 years (with plans to go to 16+ years in Spring 2018). In addition to the precipitation estimates, each data set provides fields of other variables, such as the satellite sensor providing estimates and estimated random error. The discussion concludes with advice about determining suitability for use, the necessity of being clear about product names and versions, and the need for continued support for satellite- and surface-based observation.

Satellite-based laser windsounder

International Nuclear Information System (INIS)

Schultz, J.F.; Czuchlewski, S.J.; Quick, C.R.

1997-01-01

This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project''s primary objective is to determine the technical feasibility of using satellite-based laser wind sensing systems for detailed study of winds, aerosols, and particulates around and downstream of suspected proliferation facilities. Extensive interactions with the relevant operational organization resulted in enthusiastic support and useful guidance with respect to measurement requirements and priorities. Four candidate wind sensing techniques were evaluated, and the incoherent Doppler technique was selected. A small satellite concept design study was completed to identify the technical issues inherent in a proof-of-concept small satellite mission. Use of a Mach-Zehnder interferometer instead of a Fabry-Perot would significantly simplify the optical train and could reduce weight, and possibly power, requirements with no loss of performance. A breadboard Mach-Zehnder interferometer-based system has been built to verify these predictions. Detailed plans were made for resolving other issues through construction and testing of a ground-based lidar system in collaboration with the University of Wisconsin, and through numerical lidar wind data assimilation studies

Design of a Control System for an Autonomous Vehicle Based on Adaptive-PID

Directory of Open Access Journals (Sweden)

Pan Zhao

2012-07-01

Full Text Available The autonomous vehicle is a mobile robot integrating multi-sensor navigation and positioning, intelligent decision making and control technology. This paper presents the control system architecture of the autonomous vehicle, called “Intelligent Pioneer”, and the path tracking and stability of motion to effectively navigate in unknown environments is discussed. In this approach, a two degree-of-freedom dynamic model is developed to formulate the path-tracking problem in state space format. For controlling the instantaneous path error, traditional controllers have difficulty in guaranteeing performance and stability over a wide range of parameter changes and disturbances. Therefore, a newly developed adaptive-PID controller will be used. By using this approach the flexibility of the vehicle control system will be increased and achieving great advantages. Throughout, we provide examples and results from Intelligent Pioneer and the autonomous vehicle using this approach competed in the 2010 and 2011 Future Challenge of China. Intelligent Pioneer finished all of the competition programmes and won first position in 2010 and third position in 2011.

Robotics Vision-based Heuristic Reasoning for Underwater Target Tracking and Navigation

Directory of Open Access Journals (Sweden)

Chua Kia

2005-09-01

Full Text Available This paper presents a robotics vision-based heuristic reasoning system for underwater target tracking and navigation. This system is introduced to improve the level of automation of underwater Remote Operated Vehicles (ROVs operations. A prototype which combines computer vision with an underwater robotics system is successfully designed and developed to perform target tracking and intelligent navigation. This study focuses on developing image processing algorithms and fuzzy inference system for the analysis of the terrain. The vision system developed is capable of interpreting underwater scene by extracting subjective uncertainties of the object of interest. Subjective uncertainties are further processed as multiple inputs of a fuzzy inference system that is capable of making crisp decisions concerning where to navigate. The important part of the image analysis is morphological filtering. The applications focus on binary images with the extension of gray-level concepts. An open-loop fuzzy control system is developed for classifying the traverse of terrain. The great achievement is the system's capability to recognize and perform target tracking of the object of interest (pipeline in perspective view based on perceived condition. The effectiveness of this approach is demonstrated by computer and prototype simulations. This work is originated from the desire to develop robotics vision system with the ability to mimic the human expert's judgement and reasoning when maneuvering ROV in the traverse of the underwater terrain.

Robotics Vision-based Heuristic Reasoning for Underwater Target Tracking and Navigation

Directory of Open Access Journals (Sweden)

Chua Kia

2008-11-01

Full Text Available This paper presents a robotics vision-based heuristic reasoning system for underwater target tracking and navigation. This system is introduced to improve the level of automation of underwater Remote Operated Vehicles (ROVs operations. A prototype which combines computer vision with an underwater robotics system is successfully designed and developed to perform target tracking and intelligent navigation. This study focuses on developing image processing algorithms and fuzzy inference system for the analysis of the terrain. The vision system developed is capable of interpreting underwater scene by extracting subjective uncertainties of the object of interest. Subjective uncertainties are further processed as multiple inputs of a fuzzy inference system that is capable of making crisp decisions concerning where to navigate. The important part of the image analysis is morphological filtering. The applications focus on binary images with the extension of gray-level concepts. An open-loop fuzzy control system is developed for classifying the traverse of terrain. The great achievement is the system's capability to recognize and perform target tracking of the object of interest (pipeline in perspective view based on perceived condition. The effectiveness of this approach is demonstrated by computer and prototype simulations. This work is originated from the desire to develop robotics vision system with the ability to mimic the human expert's judgement and reasoning when maneuvering ROV in the traverse of the underwater terrain.

Development of U.S. Government General Technical Requirements for UAS Flight Safety Systems Utilizing the Iridium Satellite Constellation

Science.gov (United States)

Murray, Jennifer; Birr, Richard

2010-01-01

This slide presentation reviews the development of technical requirements for Unmanned Aircraft Systems (UAS) utilization of the Iridium Satellite Constellation to provide flight safety. The Federal Aviation Authority (FAA) required an over-the-horizon communication standard to guarantee flight safety before permitting widespread UAS flights in the National Air Space (NAS). This is important to ensure reliable control of UASs during loss-link and over-the-horizon scenarios. The core requirement was to utilize a satellite system to send GPS tracking data and other telemetry from a flight vehicle down to the ground. Iridium was chosen as the system because it is one of the only true satellite systems that has world wide coverage, and the service has a highly reliable link margin. The Iridium system, the flight modems, and the test flight are described.

Persistent Aerial Tracking

KAUST Repository

Mueller, Matthias

2016-01-01

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

Signature of biased range in the non-dynamical Chern-Simons modified gravity and its measurements with satellite-satellite tracking missions: theoretical studies

Science.gov (United States)

Qiang, Li-E.; Xu, Peng

2015-08-01

Having great accuracy in the range and range rate measurements, the GRACE mission and the planed GRACE follow on mission can in principle be employed to place strong constraints on certain relativistic gravitational theories. In this paper, we work out the range observable of the non-dynamical Chern-Simons modified gravity for the satellite-to-satellite tracking (SST) measurements. We find out that a characteristic time accumulating range signal appears in non-dynamical Chern-Simons gravity, which has no analogue found in the standard parity-preserving metric theories of gravity. The magnitude of this Chern-Simons range signal will reach a few times of cm for each free flight of these SST missions, here is the dimensionless post-Newtonian parameter of the non-dynamical Chern-Simons theory. Therefore, with the 12 years data of the GRACE mission, one expects that the mass scale of the non-dynamical Chern-Simons gravity could be constrained to be larger than eV. For the GRACE FO mission that scheduled to be launched in 2017, the much stronger bound that eV is expected.

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.

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.

Advanced satellite servicing facility studies

Science.gov (United States)

Qualls, Garry D.; Ferebee, Melvin J., Jr.

1988-01-01

A NASA-sponsored systems analysis designed to identify and recommend advanced subsystems and technologies specifically for a manned Sun-synchronous platform for satellite management is discussed. An overview of system design, manned and unmanned servicing facilities, and representative mission scenarios are given. Mission areas discussed include facility based satellite assembly, checkout, deployment, refueling, repair, and systems upgrade. The ferrying of materials and consumables to and from manufacturing platforms, deorbit, removal, repositioning, or salvage of satellites and debris, and crew rescue of any other manned vehicles are also examined. Impacted subsytems discussed include guidance navigation and control, propulsion, data management, power, thermal control, structures, life support, and radiation management. In addition, technology issues which would have significant impacts on the system design are discussed.

RFID-Based Vehicle Positioning and Its Applications in Connected Vehicles

Science.gov (United States)

Wang, Jianqiang; Ni, Daiheng; Li, Keqiang

2014-01-01

This paper proposed an RFID-based vehicle positioning approach to facilitate connected vehicles applications. When a vehicle passes over an RFID tag, the vehicle position is given by the accurate position stored in the tag. At locations without RFID coverage, the vehicle position is estimated from the most recent tag location using a kinematics integration algorithm till updates from the next tag. The accuracy of RFID positioning is verified empirically in two independent ways with one using radar and the other a photoelectric switch. The former is designed to verify whether the dynamic position obtained from RFID tags matches the position measured by radar that is regarded as accurate. The latter aims to verify whether the position estimated from the kinematics integration matches the position obtained from RFID tags. Both means supports the accuracy of RFID-based positioning. As a supplement to GPS which suffers from issues such as inaccuracy and loss of signal, RFID positioning is promising in facilitating connected vehicles applications. Two conceptual applications are provided here with one in vehicle operational control and the other in Level IV intersection control. PMID:24599188

RFID-Based Vehicle Positioning and Its Applications in Connected Vehicles

Directory of Open Access Journals (Sweden)

Jianqiang Wang

2014-03-01

Full Text Available This paper proposed an RFID-based vehicle positioning approach to facilitate connected vehicles applications. When a vehicle passes over an RFID tag, the vehicle position is given by the accurate position stored in the tag. At locations without RFID coverage, the vehicle position is estimated from the most recent tag location using a kinematics integration algorithm till updates from the next tag. The accuracy of RFID positioning is verified empirically in two independent ways with one using radar and the other a photoelectric switch. The former is designed to verify whether the dynamic position obtained from RFID tags matches the position measured by radar that is regarded as accurate. The latter aims to verify whether the position estimated from the kinematics integration matches the position obtained from RFID tags. Both means supports the accuracy of RFID-based positioning. As a supplement to GPS which suffers from issues such as inaccuracy and loss of signal, RFID positioning is promising in facilitating connected vehicles applications. Two conceptual applications are provided here with one in vehicle operational control and the other in Level IV intersection control.

Collaborative Tracking of Image Features Based on Projective Invariance

Science.gov (United States)

Jiang, Jinwei

In past manned lunar landing missions, such as Apollo 14, spatial disorientation of astronauts substantially compromised the productivities of astronauts, and caused safety and mission success problems. The non-GPS lunar environment has micro-gravity field, and lacks both spatial recognition cues and reference objects which are familiar to the human biological sensors related to spatial recognition (e.g. eyes). Such an environment causes misperceptions of the locations of astronauts and targets and their spatial relations, as well as misperceptions of the heading direction and travel distances of astronauts. These spatial disorientation effects can reduce productivity and cause life risks in lunar manned missions. A navigation system, which is capable of locating astronauts and tracking the movements of them on the lunar surface, is critical for future lunar manned missions where multiple astronauts will traverse more than 100km from the lander or the base station with the assistance from roving vehicle, and need real-time navigation support for effective collaborations among them. Our earlier research to solve these problems dealt with developing techniques to enable a precise, flexible and reliable Lunar Astronaut Spatial Orientation and Information System (LASOIS) capable of delivering real-time navigation information to astronauts on the lunar surface. The LASOIS hardware was a sensor network composed of orbital, ground and on-suit sensors: the Lunar Reconnaissance Orbiter Camera (LROC), radio beacons, the on-suit cameras, and shoe-mounted Inertial Measurement Unit (IMU). The LASOIS software included efficient and robust algorithms for estimating trajectory from IMU signals, generating heading information from imagery acquired from on-suit cameras, and an Extended Kalman Filter (EKF) based approach for integrating these spatial information components to generate the trajectory of an astronaut with meter-level accuracy. Moreover, LASOIS emphasized multi

Active disturbance rejection based trajectory linearization control for hypersonic reentry vehicle with bounded uncertainties.

Science.gov (United States)

Shao, Xingling; Wang, Honglun

2015-01-01

This paper investigates a novel compound control scheme combined with the advantages of trajectory linearization control (TLC) and alternative active disturbance rejection control (ADRC) for hypersonic reentry vehicle (HRV) attitude tracking system with bounded uncertainties. Firstly, in order to overcome actuator saturation problem, nonlinear tracking differentiator (TD) is applied in the attitude loop to achieve fewer control consumption. Then, linear extended state observers (LESO) are constructed to estimate the uncertainties acting on the LTV system in the attitude and angular rate loop. In addition, feedback linearization (FL) based controllers are designed using estimates of uncertainties generated by LESO in each loop, which enable the tracking error for closed-loop system in the presence of large uncertainties to converge to the residual set of the origin asymptotically. Finally, the compound controllers are derived by integrating with the nominal controller for open-loop nonlinear system and FL based controller. Also, comparisons and simulation results are presented to illustrate the effectiveness of the control strategy. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

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.

Real-Time Radar-Based Tracking and State Estimation of Multiple Non-Conformant Aircraft

Science.gov (United States)

Cook, Brandon; Arnett, Timothy; Macmann, Owen; Kumar, Manish

2017-01-01

In this study, a novel solution for automated tracking of multiple unknown aircraft is proposed. Many current methods use transponders to self-report state information and augment track identification. While conformant aircraft typically report transponder information to alert surrounding aircraft of its state, vehicles may exist in the airspace that are non-compliant and need to be accurately tracked using alternative methods. In this study, a multi-agent tracking solution is presented that solely utilizes primary surveillance radar data to estimate aircraft state information. Main research challenges include state estimation, track management, data association, and establishing persistent track validity. In an effort to realize these challenges, techniques such as Maximum a Posteriori estimation, Kalman filtering, degree of membership data association, and Nearest Neighbor Spanning Tree clustering are implemented for this application.

Electric vehicle data acquisition system

DEFF Research Database (Denmark)

Svendsen, Mathias; Winther-Jensen, Mads; Pedersen, Anders Bro

2014-01-01

and industrial applications, e.g. research in electric vehicle driving patterns, vehicle substitutability analysis and fleet management. The platform is based on a embedded computer running Linux, and features a high level of modularity and flexibility. The system operates independently of the make of the car......, by using the On-board Diagnostic port to identify car model and adapt its software accordingly. By utilizing on-board Global Navigation Satellite System, General Packet Radio Service, accelerometer, gyroscope and magnetometer, the system not only provides valuable data for research in the field of electric......A data acquisition system for electric vehicles is presented. The system connects to the On-board Diagnostic port of newer vehicles, and utilizes the in-vehicle sensor network, as well as auxiliary sensors, to gather data. Data is transmitted continuously to a central database for academic...

The Combat System Design and Test Criteria for Iguana TM Armored Vehicles

National Research Council Canada - National Science Library

Alper, Irfan

1999-01-01

... acoustic/IR signatures. The Iguana(trademark), a tracked vehicle concept based on a recently patented suspension and track design, could deploy to hot spots world-wide on peacekeeping and combat missions which require extra flexibility to adapt...

Quantization-Based Adaptive Actor-Critic Tracking Control With Tracking Error Constraints.

Science.gov (United States)

Fan, Quan-Yong; Yang, Guang-Hong; Ye, Dan

2018-04-01

In this paper, the problem of adaptive actor-critic (AC) tracking control is investigated for a class of continuous-time nonlinear systems with unknown nonlinearities and quantized inputs. Different from the existing results based on reinforcement learning, the tracking error constraints are considered and new critic functions are constructed to improve the performance further. To ensure that the tracking errors keep within the predefined time-varying boundaries, a tracking error transformation technique is used to constitute an augmented error system. Specific critic functions, rather than the long-term cost function, are introduced to supervise the tracking performance and tune the weights of the AC neural networks (NNs). A novel adaptive controller with a special structure is designed to reduce the effect of the NN reconstruction errors, input quantization, and disturbances. Based on the Lyapunov stability theory, the boundedness of the closed-loop signals and the desired tracking performance can be guaranteed. Finally, simulations on two connected inverted pendulums are given to illustrate the effectiveness of the proposed method.

Trajectory planning and tracking for autonomous vehicles navigation

OpenAIRE

Chebly , Alia

2017-01-01

In this thesis, the trajectory planning and the control of autonomous vehicles are addressed. As a first step, a multi-body modeling technique is used to develop a four wheeled vehicle planar model. This technique considers the vehicle as a robot consisting of articulated bodies. The geometric description of the vehicle system is derived using the modified Denavit Hartenberg parameterization and then the dynamic model of the vehicle is computed by applying a recursive method used in robotics,...

Test bed for applications of heterogeneous unmanned vehicles

Directory of Open Access Journals (Sweden)

Filiberto Muñoz Palacios

2017-01-01

Full Text Available This article addresses the development and implementation of a test bed for applications of heterogeneous unmanned vehicle systems. The test bed consists of unmanned aerial vehicles (Parrot AR.Drones versions 1 or 2, Parrot SA, Paris, France, and Bebop Drones 1.0 and 2.0, Parrot SA, Paris, France, ground vehicles (WowWee Rovio, WowWee Group Limited, Hong Kong, China, and the motion capture systems VICON and OptiTrack. Such test bed allows the user to choose between two different options of development environments, to perform aerial and ground vehicles applications. On the one hand, it is possible to select an environment based on the VICON system and LabVIEW (National Instruments or robotics operating system platforms, which make use the Parrot AR.Drone software development kit or the Bebop_autonomy Driver to communicate with the unmanned vehicles. On the other hand, it is possible to employ a platform that uses the OptiTrack system and that allows users to develop their own applications, replacing AR.Drone’s original firmware with original code. We have developed four experimental setups to illustrate the use of the Parrot software development kit, the Bebop Driver (AutonomyLab, Simon Fraser University, British Columbia, Canada, and the original firmware replacement for performing a strategy that involves both ground and aerial vehicle tracking. Finally, in order to illustrate the effectiveness of the developed test bed for the implementation of advanced controllers, we present experimental results of the implementation of three consensus algorithms: static, adaptive, and neural network, in order to accomplish that a team of multiagents systems move together to track a target.

Reviewing Automated Sensor-Based Visitor Tracking Studies

DEFF Research Database (Denmark)

Mygind, Lærke; Bentsen, Peter

2017-01-01

The method of timing and tracking has a long history within visitor studies and exhibition evaluation. With an increase in indoor tracking research, sensor-based positioning tool usage in museums has grown, as have expectations regarding the efficacy of technological sensing systems. This literat......The method of timing and tracking has a long history within visitor studies and exhibition evaluation. With an increase in indoor tracking research, sensor-based positioning tool usage in museums has grown, as have expectations regarding the efficacy of technological sensing systems...... methods in terms of obtained level of detail, accuracy, level of obtrusiveness, automation of data entry, ability to time concurrent behaviors, and amount of observer training needed. Although individual sensor-based and traditional, observational methods had both strengths and weaknesses, all sensor......-based timing and tracking methods provided automated data entry and the opportunity to track a number of visitors simultaneously regardless of the available personnel....

Migration of Tundra Swans (Cygnus columbianus) Wintering in Japan Using Satellite Tracking: Identification of the Eastern Palearctic Flyway.

Science.gov (United States)

Chen, Wenbo; Doko, Tomoko; Fujita, Go; Hijikata, Naoya; Tokita, Ken-Ichi; Uchida, Kiyoshi; Konishi, Kan; Hiraoka, Emiko; Higuchi, Hiroyoshi

2016-02-01

Migration through the Eastern Palearctic (EP) flyway by tundra swans (Cygnus columbianus) has not been thoroughly documented. We satellite-tracked the migration of 16 tundra swans that winter in Japan. The objectives of this study were 1) to show the migration pattern of the EP flyway of tundra swans; 2) to compare this pattern with the migration pattern of whooper swans; and 3) to identify stopover sites that are important for these swans' conservation. Tundra swans were captured at Kutcharo Lake, Hokkaido, in 2009-2012 and satellite-tracked. A new method called the "MATCHED (Migratory Analytical Time Change Easy Detection) method" was developed. Based on median, the spring migration began on 18 April and ended on 27 May. Autumn migration began on 9 September and ended on 2 November. The median duration of the spring and autumn migrations were 48 and 50 days, respectively. The mean duration at one stopover site was 5.5 days and 6.8 days for the spring and autumn migrations, respectively. The number of stopover sites was 3.0 and 2.5 for the spring and autumn migrations, respectively. The mean travel distances for the spring and autumn migrations were 6471 and 6331 km, respectively. Seven migration routes passing Sakhalin, the Amur River, and/or Kamchatka were identified. There were 15, 32, and eight wintering, stopover, and breeding sites, respectively. The migration routes and staging areas of tundra swans partially overlap with those of whooper swans, whose migration patterns have been previously documented. The migration patterns of these two swan species that winter in Japan confirm the importance of the Amur River, Udyl' Lake, Shchastya Bay, Aniva Bay, zaliv Chayvo Lake, zal Piltun Lake, zaliv Baykal Lake, Kolyma River, Buyunda River, Sen-kyuyel' Lake, and northern coastal areas of the Sea of Okhotsk.

Point Cloud Based Relative Pose Estimation of a Satellite in Close Range

Directory of Open Access Journals (Sweden)

Lujiang Liu

2016-06-01

Full Text Available Determination of the relative pose of satellites is essential in space rendezvous operations and on-orbit servicing missions. The key problems are the adoption of suitable sensor on board of a chaser and efficient techniques for pose estimation. This paper aims to estimate the pose of a target satellite in close range on the basis of its known model by using point cloud data generated by a flash LIDAR sensor. A novel model based pose estimation method is proposed; it includes a fast and reliable pose initial acquisition method based on global optimal searching by processing the dense point cloud data directly, and a pose tracking method based on Iterative Closest Point algorithm. Also, a simulation system is presented in this paper in order to evaluate the performance of the sensor and generate simulated sensor point cloud data. It also provides truth pose of the test target so that the pose estimation error can be quantified. To investigate the effectiveness of the proposed approach and achievable pose accuracy, numerical simulation experiments are performed; results demonstrate algorithm capability of operating with point cloud directly and large pose variations. Also, a field testing experiment is conducted and results show that the proposed method is effective.

SALIENCY BASED SEGMENTATION OF SATELLITE IMAGES

Directory of Open Access Journals (Sweden)

A. Sharma

2015-03-01

Full Text Available Saliency gives the way as humans see any image and saliency based segmentation can be eventually helpful in Psychovisual image interpretation. Keeping this in view few saliency models are used along with segmentation algorithm and only the salient segments from image have been extracted. The work is carried out for terrestrial images as well as for satellite images. The methodology used in this work extracts those segments from segmented image which are having higher or equal saliency value than a threshold value. Salient and non salient regions of image become foreground and background respectively and thus image gets separated. For carrying out this work a dataset of terrestrial images and Worldview 2 satellite images (sample data are used. Results show that those saliency models which works better for terrestrial images are not good enough for satellite image in terms of foreground and background separation. Foreground and background separation in terrestrial images is based on salient objects visible on the images whereas in satellite images this separation is based on salient area rather than salient objects.

Digital Tracking Array for FM Signals Based on Off-The-Shelf Wireless Technologies

National Research Council Canada - National Science Library

Edmund, Hui K

2007-01-01

... a 2.4 GHz frequency modulation (FM) video signal from an unmanned air vehicle. The tracking is done using a monopulse technique Various numbers of elements were simulated to access the pattern coverage...

State-of-the-art assessment of electric and hybrid vehicles

Science.gov (United States)

1978-01-01

Data are presented that were obtained from the electric and hybrid vehicles tested, information collected from users of electric vehicles, and data and information on electric and hybrid vehicles obtained on a worldwide basis from manufacturers and available literature. The data given include: (1) information and data base (electric and hybrid vehicle systems descriptions, sources of vehicle data and information, and sources of component data); (2) electric vehicles (theoretical background, electric vehicle track tests, user experience, literature data, and summary of electric vehicle status); (3) electric vehicle components (tires, differentials, transmissions, traction motors, controllers, batteries, battery chargers, and component summary); and (4) hybrid vehicles (types of hybrid vehicles, operating modes, hybrid vehicles components, and hybrid vehicles performance characteristics).

Antarctic Iceberg Tracking Based on Time Series of Aqua AMSR-E Microwave Brightness Temperature Measurements

Science.gov (United States)

Blonski, S.; Peterson, C. A.

2006-12-01

) of NASA's (National Aeronautics and Space Administration) Applied Science Program to demonstrate that passive microwave brightness temperature measurements acquired by AMSR-E can be effectively used to track iceberg movement around Antarctica. The RPC's robust computation environment enabled processing of terabytes of data products available from the NASA Distributed Active Archive Center at the National Snow and Ice Data Center. Iceberg tracking based on the AMSR-E Level 2A data product was compared with records from the National Ice Center for currently existing icebergs. Some icebergs as small as roughly 10 km in size were easily observed, but tracking of many others, even larger ones, was obscured by presence of sea ice surrounding the icebergs. The best results, such as for the large iceberg A22A, were achieved when an iceberg was in open ocean. Outcomes of this RPC experiment can be presented to other government agencies to explore possibilities for incorporation of these NASA Earth science research results into the decision support environments of the other agencies. The most promising is the option to extend current operational observations to areas north of the 60°S parallel. Moreover, because of similarity of spatial resolution characteristics between 89-GHz channels of AMSR-E and the future GMI (GPM Microwave Imager) radiometer from the core satellite of the GPM (Global Precipitation Measurement) mission, this experiment also indicates potential operational uses of upcoming NASA Earth observation data products.

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.

Landscape Characteristics of Oriental Honey Buzzards Wintering in Western Part of Flores Island Based on Satellite-Tracking Data

Science.gov (United States)

Syartinilia; Farisi, G. H. Al; Higuchi, H.

2017-10-01

Oriental Honey Buzzards (OHBs, Pernis ptilorhynchus) are migratory raptor that has been satellite-tracked since 2003. Some islands in Indonesia which are used for wintering habitat are Flores and Borneo. However, both islands have different characteristics of climate and land cover. The objectives of this research were to analyze the landscape characteristic of the OHBs wintering habitat in western Flores, and to subsequently compare landscape characteristic of the OHBs wintering habitat in Borneo. Landscape habitat characteristics were analyzed using Principal Component Analysis (PCA) combined with GIS and then compared to the previous study in Borneo Island. The result showed that the first of six principal components explained 79.14% and 77.59% of the observed variation in landscape characteristics of both core and edge habitats, subsequently. Habitat selection by OHBs at wintering site was influenced by the availability of thermal wind and food. Savannah was identified as the main landscape characteristic that was different between wintering habitat in Flores and Borneo. Savannah is well-known as a habitat for many species of amphibians, reptiles, and small mammals so that it can be a hunting area that provide alternative feed for OHBs.

Longitudinal Control for Mengshi Autonomous Vehicle via Cloud Model

Science.gov (United States)

Gao, H. B.; Zhang, X. Y.; Li, D. Y.; Liu, Y. C.

2018-03-01

Dynamic robustness and stability control is a requirement for self-driving of autonomous vehicle. Longitudinal control method of autonomous is a key technique which has drawn the attention of industry and academe. In this paper, we present a longitudinal control algorithm based on cloud model for Mengshi autonomous vehicle to ensure the dynamic stability and tracking performance of Mengshi autonomous vehicle. An experiments is applied to test the implementation of the longitudinal control algorithm. Empirical results show that if the longitudinal control algorithm based Gauss cloud model are applied to calculate the acceleration, and the vehicles drive at different speeds, a stable longitudinal control effect is achieved.

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

A Coupling Vibration Test Bench and the Simulation Research of a Maglev Vehicle

Directory of Open Access Journals (Sweden)

Weihua Ma

2015-01-01

Full Text Available To study the characteristics of the coupling vibration between a maglev vehicle and its track beam system and to improve the performance of the levitation system, a new type of vibration test bench was developed. Take a single maglev frame as the study object; simulation of the coupling vibration of the maglev vehicle, levitation system, and track beam were achieved. In addition, all types of real track irregularity excitations can be simulated using hydraulic actuators of the test bench. To expand the research scope, a simulation model was developed that can conduct the simulation research synergistically with the test bench. Based on a dynamics model of the test bench, the dynamics simulation method determined the influence on the levitation control performance of three factors: the track beam support stiffness, the track beam mass, and the track irregularity. The vibration resonance phenomenon of the vehicle/track system was reproduced by the dynamics simulation, and a portion of the simulation results were validated by the test results. By combining the test bench and the dynamics model, experiments can be guided by the simulation results, and the experimental results can validate the dynamics simulation results.

GLONASS satellite monitoring of nuclear transports

International Nuclear Information System (INIS)

Davydov, Yu.L.

2012-01-01

In 2011 Rosatom has made the decision to create the industry-wide automated system for monitoring of transports of radioactive substances (RS) and wastes (RAW), as well as hazardous loads by rail and automobile, based upon the same hardware as used by the GLONASS satellite navigation system - the so-called ASBT-GLONASS system. The new system will use the same technical infrastructure as the existing operational Automated System for Safe Transport of Nuclear Materials of Categories I and II (ASBT). The ASBT structure includes a network of control centres fitted with automation and communication hardware. In addition, ASBT includes technical complexes installed upon transport vehicles intended for nuclear material transport. In order to identify transport vehicle location, the GLONASS/GPS (GALS-P-ASBT) satellite navigational receiver device is used, it is developed especially for ASBT systems taking in account information security requirements. By now the basic software and hardware complex ASBT-GLONASS has been created (equipment to be carried on-board the transport vehicle loaded with RS and RAW, as well as the transport control stations) that supports transport monitoring and transmission of an emergency signal to control stations of companies which deal with RS and RAW transportation [ru

Mapping plasma structures in the high-latitude ionosphere using beacon satellite, incoherent scatter radar and ground-based magnetometer observations

Directory of Open Access Journals (Sweden)

T. Neubert

2002-06-01

Full Text Available In the autumn of the year 2000, four radio receivers capable of tracking various beacon satellites were set up along the southwestern coast of Greenland. They are used to reconstruct images of the ionospheric plasma density distribution via the tomographic method. In order to test and validate tomographic imaging under the highly variable conditions often prevailing in the high-latitude ionosphere, a time interval was selected when the Sondrestrom incoherent scatter radar conducted measurements of the ionospheric plasma density while the radio receivers tracked a number of beacon satellites. A comparison between two-dimensional images of the plasma density distribution obtained from the radar and the satellite receivers revealed generally good agreement between radar measurements and tomographic images. Observed discrepancies can be attributed to F region plasma patches moving through the field of view with a speed of several hundred meters per second, thereby smearing out the tomographic image. A notable mismatch occurred around local magnetic midnight when a magnetospheric substorm breakup occurred in the vicinity of southwest Greenland (identified from ground-based magnetometer observations. The breakup was associated with a sudden intensification of the westward auroral electrojet which was centered at about 69 and extended up to some 73 corrected geomagnetic latitude. Ground-based magnetometer data may thus have the potential of indicating when the tomographic method is at risk and may fail. We finally outline the application of tomographic imaging, when combined with magnetic field data, to estimate ionospheric Joule heating rates.

A Lateral Control Method of Intelligent Vehicle Based on Fuzzy Neural Network

Directory of Open Access Journals (Sweden)

Linhui Li

2015-01-01

Full Text Available A lateral control method is proposed for intelligent vehicle to track the desired trajectory. Firstly, a lateral control model is established based on the visual preview and dynamic characteristics of intelligent vehicle. Then, the lateral error and orientation error are melded into an integrated error. Considering the system parameter perturbation and the external interference, a sliding model control is introduced in this paper. In order to design a sliding surface, the integrated error is chosen as the parameter of the sliding mode switching function. The sliding mode switching function and its derivative are selected as two inputs of the controller, and the front wheel angle is selected as the output. Next, a fuzzy neural network is established, and the self-learning functions of neural network is utilized to construct the fuzzy rules. Finally, the simulation results demonstrate the effectiveness and robustness of the proposed method.

Lock threshold deterioration induced by antenna vibration and signal coupling effects in hypersonic vehicle carrier tracking system of Ka band

Directory of Open Access Journals (Sweden)

Congying ZHU

2018-04-01

Full Text Available The envelope of a hypersonic vehicle is affected by severe fluctuating pressure, which causes the airborne antenna to vibrate slightly. This vibration mixes with the transmitted signals and thus introduces additional multiplicative phase noise. Antenna vibration and signal coupling effects as well as their influence on the lock threshold of the hypersonic vehicle carrier tracking system of the Ka band are investigated in this study. A vibration model is initially established to obtain phase noise in consideration of the inherent relationship between vibration displacement and electromagnetic wavelength. An analytical model of the Phase-Locked Loop (PLL, which is widely used in carrier tracking systems, is established. The coupling effects on carrier tracking performance are investigated and quantitatively analyzed by imposing the multiplicative phase noise on the PLL model. Simulation results show that the phase noise presents a Gaussian distribution and is similar to vibration displacement variation. A large standard deviation in vibration displacement exerts a significant effect on the lock threshold. A critical standard deviation is observed in the PLL of Binary Phase Shift Keying (BPSK and Quadrature Phase Shift Keying (QPSK signals. The effect on QPSK signals is more severe than that on BPSK signals. The maximum tolerable standard deviations normalized by the wavelength of the carrier are 0.04 and 0.02 for BPSK and QPSK signals, respectively. With these critical standard deviations, lock thresholds are increased from −12 and −4 dB to 3 and −2 dB, respectively. Keywords: Antenna vibration, Carrier tracking performance, Lock threshold, Phase locked loop, Tracking Telemetry and Command (TT&C signals

Graph Model Based Indoor Tracking

DEFF Research Database (Denmark)

Jensen, Christian Søndergaard; Lu, Hua; Yang, Bin

2009-01-01

The tracking of the locations of moving objects in large indoor spaces is important, as it enables a range of applications related to, e.g., security and indoor navigation and guidance. This paper presents a graph model based approach to indoor tracking that offers a uniform data management...

Precise object tracking under deformation

International Nuclear Information System (INIS)

Saad, M.H

2010-01-01

The precise object tracking is an essential issue in several serious applications such as; robot vision, automated surveillance (civil and military), inspection, biomedical image analysis, video coding, motion segmentation, human-machine interface, visualization, medical imaging, traffic systems, satellite imaging etc. This frame-work focuses on the precise object tracking under deformation such as scaling , rotation, noise, blurring and change of illumination. This research is a trail to solve these serious problems in visual object tracking by which the quality of the overall system will be improved. Developing a three dimensional (3D) geometrical model to determine the current pose of an object and predict its future location based on FIR model learned by the OLS. This framework presents a robust ranging technique to track a visual target instead of the traditional expensive ranging sensors. The presented research work is applied to real video stream and achieved high precession results.

Defining management units for cetaceans by combining genetics, morphlogy, acoustics and satellite tracking

DEFF Research Database (Denmark)

Sveegaard, Signe; Galatius, Anders; Dietz, Rune

2015-01-01

Managing animal units is essential in biological conservation and requires spatial and temporal identification of such units. Since even neighbouring populations often have different conservation status and face different levels of anthropogenic pressure, detailed knowledge of population structure......, seasonal range and overlap with animals from neighbouring populations is required to manage each unit separately. Previous studies on genetic structure and morphologic separation suggests three distinct populations of harbour porpoises with limited geographic overlap in the North Sea (NS), the Belt Sea (BS...... with the least overlap between populations and thus the least error when abundance and population status is estimated. Discriminant analysis of the satellite tracking data from the BS and NS populations showed that the best fit of the management unit border during the summer months was an east-west line from...

Kinematic Orbit Determination Method Optimization and Test Analysis for BDS Satellites with Short-arc Tracking Data

Directory of Open Access Journals (Sweden)

GUO Rui

2017-04-01

Full Text Available Rapid orbit recovery is a puzzle for the BDS satellites after orbit maneuvers. Two kinematic orbit determination methods are studied, with two orbit determination models being established. The receiver system error and serious multipath error exist in the BDS system. The co-location method is proposed to estimate and calibrate the receiver system errors. A CNMC (code noise and multipath correction method is introduced to weaken the multipath error. Therefore the data quality is controlled efficiently for the receivers in the short tracking arc. The GEO/IGSO/MEO real data is emploied to carry out tests and validation. Using 10 min short tracking arc, the kinematic precise orbit determination accuracy is about 3.27 m for the GEOs, and 8.19 m for the IGSOs, and 5.9 m for the MEOs. Rapid orbit determination is achieved, which satisfying the orbit requirements from the BDS RDSS services. The kinematic precise orbit determination method also supports the RDSS service walking up to the global world.

Electric and hybrid vehicles

Science.gov (United States)

1979-01-01

Report characterizes state-of-the-art electric and hybrid (combined electric and heat engine) vehicles. Performance data for representative number of these vehicles were obtained from track and dynamometer tests. User experience information was obtained from fleet operators and individual owners of electric vehicles. Data on performance and physical characteristics of large number of vehicles were obtained from manufacturers and available literature.

Light vehicle crash avoidance needs and countermeasure profiles for safety applications based on vehicle-to-vehicle communications

Science.gov (United States)

2013-04-30

This report discusses light-vehicle crash countermeasure profiles and functions for five target pre-crash scenario groups based on vehicle-to-vehicle (V2V) communications. Target pre-crash scenario groups include rear-end, lane change, opposite direc...

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.

Design of a positional tracking and radiological alarm system for transportation of radioactive isotopes

International Nuclear Information System (INIS)

Saindane, Shashank; Pujari, R.N.; Narsaiah, M.V.R.; Chaudhury, Probal; Pradeepkumar, K.S.

2016-01-01

The safety aspects during the transport of radioactive material have to ensure that even in event of accident the potential of radiation exposure to public is extremely small. Continuous monitoring and online data transfer to emergency control room will strengthen the emergency preparedness to response to any such accident during transport of radioactive material. The paper presents the combined application of Geographical Information Systems (GIS), Global Positioning System (GPS), General Packet Radio Service (GPRS) and the Internet for tracking the shipment vehicle transporting radioactive isotopes for use in the medical industry. The key features of the prototype system designed are realtime radiological status update along with photo snap of the shipping flask at predefined interval along with positional coordinates, GIS platform and a web-based user interface. The system consists of a GM based radiation monitoring device (RMD) along with a LAN camera, GPS for tracking the shipment vehicle, a communications server, a web-server, a database server, and a map server. The RMD and tracking device mounted in the shipment vehicle collects location and radiological information on real-time via the GPS. This information is transferred continuously through GPRS to a central database. The users will be able to view the current location of the vehicle via a web-based application

Ground test of satellite constellation based quantum communication

OpenAIRE

Liao, Sheng-Kai; Yong, Hai-Lin; Liu, Chang; Shentu, Guo-Liang; Li, Dong-Dong; Lin, Jin; Dai, Hui; Zhao, Shuang-Qiang; Li, Bo; Guan, Jian-Yu; Chen, Wei; Gong, Yun-Hong; Li, Yang; Lin, Ze-Hong; Pan, Ge-Sheng

2016-01-01

Satellite based quantum communication has been proven as a feasible way to achieve global scale quantum communication network. Very recently, a low-Earth-orbit (LEO) satellite has been launched for this purpose. However, with a single satellite, it takes an inefficient 3-day period to provide the worldwide connectivity. On the other hand, similar to how the Iridium system functions in classic communication, satellite constellation (SC) composed of many quantum satellites, could provide global...

Design Concepts for a Small Space-Based GEO Relay Satellite for Missions Between Low Earth and near Earth Orbits

Science.gov (United States)

Bhasin, Kul B.; Warner, Joseph D.; Oleson, Steven; Schier, James

2014-01-01

the number of links looking above and below GEO; the detailed design of a GEO SSBS spacecraft bus and its accommodation of the communication payload, and a summary of the trade study that resulted in the selection of the Falcon 9 launch vehicle to deploy the SSBS and its impact on cost reductions per satellite. ======================================================================== Several initiatives have taken place within NASA1 and international space agencies2 to create a human exploration strategy for expanding human presence into the solar system; these initiatives have been driven by multiple factors to benefit Earth. Of the many elements in the strategy one stands out: to send robotic and human missions to destinations beyond Low Earth Orbit (LEO), including cis-lunar space, Near-Earth Asteroids (NEAs), the Moon, and Mars and its moons.3, 4 The time frame for human exploration to various destinations, based on the public information available,1,4 is shown in Figure 1. Advance planning is needed to define how future space communications services will be provided in the new budget environment to meet future space communications needs. The spacecraft for these missions can be dispersed anywhere from below LEO to beyond GEO, and to various destinations within the solar system. NASA's Space Communications and Navigation (SCaN) program office provides communication and tracking services to space missions during launch, in-orbit testing, and operation phases. Currently, SCaN's space networking relay satellites mainly provide services to users below GEO, at Near Earth Orbit (NEO), below LEO, and in deep space. The potential exists for using a space-based relay satellite, located in the vicinity of various solar system destinations, to provide communication space links to missions both below and above its orbit. Such relays can meet the needs of human exploration missions for maximum connectivity to Earth locations and for reduced latency. In the past, several studies

Supercavitating Projectile Tracking System and Method

Science.gov (United States)

2009-12-30

Distribution is unlimited 20100104106 Attorney Docket No. 96681 SUPERCAVITATING PROJECTILE TRACKING SYSTEM AND METHOD STATEMENT OF GOVERNMENT...underwater track or path 14 of a supercavitating vehicle under surface 16 of a body of water. In this embodiment, passive acoustic or pressure...transducers 12 are utilized to measure a pressure field produced by a moving supercavitating vehicle. The present invention provides a low-cost, reusable

Geostationary satellite estimation of biomass burning in Amazonia during BASE-A

International Nuclear Information System (INIS)

Menzel, W.P.; Cutrim, E.C.; Prins, E.M.

1991-01-01

This chapter presents the results of using Geostationary Operational Environmental Satellite (GOES) Visible Infrared Spin Scan Radiometer Atmospheric Sounder (VAS) infrared window (3.9 and 11.2 microns) data to monitor biomass burning several times per day in Amazonia. The technique of Matson and Dozier using two window channels was adapted to GOES VAS infrared data to estimate the size and temperature of fires associated with deforestation in the vicinity of Alta Floresta, Brazil, during the Biomass Burning Airborne and Spaceborne Experiment - Amazonia (BASE-A). Although VAS data do not offer the spatial resolution available with AVHRR data 97 km versus 1 km, respectively, this decreased resolution does not seem to hinder the ability of the VAS instrument to detect fires; in some cases it proves to be advantageous in that saturation does not occur as often. VAS visible data are additionally helpful in verifying that the hot spots sensed in the infrared are actually related to fires. Furthermore, the fire plumes can be tracked in time to determine their motion and extent. In this way, the GOES satellite offers a unique ability to monitor diurnal variations in fire activity and transport of related aerosols

Land mobile satellite services in Europe

Science.gov (United States)

Bartholomé, P.; Berretta, G.; Rogard, R.

The demand for land-mobile communications on a Europe-wide basis is an important and pressing problem. The pan-European cellular network now in the planning stage will be slow in coming and it will have its limitations. A regional satellite system for Europe to complement the cellular network is the only practical way to satisfy a specialised market that encompasses a population of several hundred thousand mobiles, including road vehicles, merchant shipping, fishing boats, and trains. The deployment of a regional system would take place in a number of phases, the first being based on a simple payload embarked on a host satellite belonging to a European organisation. Further phases will involve the development of more advanced payloads on dedicated satellites. For the long-term future, the use of satellites in highly inclined orbits is being considered as a means of improving their visibility and hence the service quality.

Track classification within wireless sensor network

Science.gov (United States)

Doumerc, Robin; Pannetier, Benjamin; Moras, Julien; Dezert, Jean; Canevet, Loic

2017-05-01

In this paper, we present our study on track classification by taking into account environmental information and target estimated states. The tracker uses several motion model adapted to different target dynamics (pedestrian, ground vehicle and SUAV, i.e. small unmanned aerial vehicle) and works in centralized architecture. The main idea is to explore both: classification given by heterogeneous sensors and classification obtained with our fusion module. The fusion module, presented in his paper, provides a class on each track according to track location, velocity and associated uncertainty. To model the likelihood on each class, a fuzzy approach is used considering constraints on target capability to move in the environment. Then the evidential reasoning approach based on Dempster-Shafer Theory (DST) is used to perform a time integration of this classifier output. The fusion rules are tested and compared on real data obtained with our wireless sensor network.In order to handle realistic ground target tracking scenarios, we use an autonomous smart computer deposited in the surveillance area. After the calibration step of the heterogeneous sensor network, our system is able to handle real data from a wireless ground sensor network. The performance of this system is evaluated in a real exercise for intelligence operation ("hunter hunt" scenario).

Remote Marker-Based Tracking for UAV Landing Using Visible-Light Camera Sensor.

Science.gov (United States)

Nguyen, Phong Ha; Kim, Ki Wan; Lee, Young Won; Park, Kang Ryoung

2017-08-30

Unmanned aerial vehicles (UAVs), which are commonly known as drones, have proved to be useful not only on the battlefields where manned flight is considered too risky or difficult, but also in everyday life purposes such as surveillance, monitoring, rescue, unmanned cargo, aerial video, and photography. More advanced drones make use of global positioning system (GPS) receivers during the navigation and control loop which allows for smart GPS features of drone navigation. However, there are problems if the drones operate in heterogeneous areas with no GPS signal, so it is important to perform research into the development of UAVs with autonomous navigation and landing guidance using computer vision. In this research, we determined how to safely land a drone in the absence of GPS signals using our remote maker-based tracking algorithm based on the visible light camera sensor. The proposed method uses a unique marker designed as a tracking target during landing procedures. Experimental results show that our method significantly outperforms state-of-the-art object trackers in terms of both accuracy and processing time, and we perform test on an embedded system in various environments.

Vehicle with inclinable caterpillar propulsion units

International Nuclear Information System (INIS)

Clar, G.

1991-01-01

This vehicle usable in hostile environment such nuclear industry has four propulsion units with a caterpillar track and two integrated motors: one for advancing the caterpillar track and the other for inclining the propulsion unit when overcoming obstacles. Each propulsion unit is easily replaceable because there are no mechanical parts in the body of the vehicle [fr

Vehicle ego-motion estimation with geometric algebra

NARCIS (Netherlands)

Mark, W. van der; Fontijne, D.; Dorst, L.; Groen, F.C.A.

2003-01-01

A method for estimating ego-motion with vehicle mounted stereo cameras is presented. This approach is based on finding corresponding features in stereo images and tracking them between succeeding stereo frames. Our approach estimates stereo ego-motion with geometric algebra techniques. Starting with

Inertial Measurement Units-Based Probe Vehicles: Automatic Calibration, Trajectory Estimation, and Context Detection

KAUST Repository

Mousa, Mustafa

2017-12-06

Most probe vehicle data is generated using satellite navigation systems, such as the Global Positioning System (GPS), Globalnaya navigatsionnaya sputnikovaya Sistema (GLONASS), or Galileo systems. However, because of their high cost, relatively high position uncertainty in cities, and low sampling rate, a large quantity of satellite positioning data is required to estimate traffic conditions accurately. To address this issue, we introduce a new type of traffic monitoring system based on inexpensive inertial measurement units (IMUs) as probe sensors. IMUs as traffic probes pose unique challenges in that they need to be precisely calibrated, do not generate absolute position measurements, and their position estimates are subject to accumulating errors. In this paper, we address each of these challenges and demonstrate that the IMUs can reliably be used as traffic probes. After discussing the sensing technique, we present an implementation of this system using a custom-designed hardware platform, and validate the system with experimental data.

Inertial Measurement Units-Based Probe Vehicles: Automatic Calibration, Trajectory Estimation, and Context Detection

KAUST Repository

Mousa, Mustafa; Sharma, Kapil; Claudel, Christian G.

2017-01-01

Most probe vehicle data is generated using satellite navigation systems, such as the Global Positioning System (GPS), Globalnaya navigatsionnaya sputnikovaya Sistema (GLONASS), or Galileo systems. However, because of their high cost, relatively high position uncertainty in cities, and low sampling rate, a large quantity of satellite positioning data is required to estimate traffic conditions accurately. To address this issue, we introduce a new type of traffic monitoring system based on inexpensive inertial measurement units (IMUs) as probe sensors. IMUs as traffic probes pose unique challenges in that they need to be precisely calibrated, do not generate absolute position measurements, and their position estimates are subject to accumulating errors. In this paper, we address each of these challenges and demonstrate that the IMUs can reliably be used as traffic probes. After discussing the sensing technique, we present an implementation of this system using a custom-designed hardware platform, and validate the system with experimental data.

Use of along-track magnetic field differences in lithospheric field modelling

DEFF Research Database (Denmark)

Kotsiaros, Stavros; Finlay, Chris; Olsen, Nils

2015-01-01

. Experiments in modelling the Earth's lithospheric magnetic field with along-track differences are presented here as a proof of concept. We anticipate that use of such along-track differences in combination with east–west field differences, as are now provided by the Swarm satellite constellation......We demonstrate that first differences of polar orbiting satellite magnetic data in the along-track direction can be used to obtain high resolution models of the lithospheric field. Along-track differences approximate the north–south magnetic field gradients for non-polar latitudes. In a test case......, using 2 yr of low altitude data from the CHAMP satellite, we show that use of along-track differences of vector field data results in an enhanced recovery of the small scale lithospheric field, compared to the use of the vector field data themselves. We show that the along-track technique performs...

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.

The vertical and the longitudinal dynamic responses of the vehicle-track system to squat-type short wavelength irregularity

Science.gov (United States)

Zhao, Xin; Li, Zili; Dollevoet, Rolf

2013-12-01

The squat, a kind of rolling contact fatigue occurring on the rail top, can excite the high-frequency vehicle-track interaction effectively due to its geometric deviations with a typical wavelength of 20-40 mm, leading to the accelerated deterioration of a track. In this work, a validated 3D transient finite element model is employed to calculate in the time domain the vertical and the longitudinal dynamic contact forces between the wheel and the rail caused by squats. The vehicle-track structure and the wheel-rail continua are both considered in order to include all the important eigencharacteristics of the system related to squats. By introducing the rotational and translational movements of the wheel, the transient wheel-rail rolling contact is solved in detail by a 3D frictional contact model integrated. The contact filter effect is considered automatically in the simulations by the finite size of the contact patch. The present work focuses on the influences of the length, width and depth of a light squat on the resulted dynamic contact forces, for which idealised defect models are used. The growth of a squat is also modelled to a certain extent by a series of defects with different dimensions. The results show that the system is mainly excited at two frequencies separately in the vertical and the longitudinal dynamics. Their superposition explains the typical appearance of mature squats. As a squat grows up, the magnitude of the excited vibration at the lower frequency increases faster than the one at the higher frequency.

Vehicle with inclinable caterpillars

International Nuclear Information System (INIS)

Carra, O.; Delevallee, A.

1991-01-01

Vehicle has a body with propulsion assemblies that drive caterpillar tracks. When a propulsion unit inclines about its articulation axis it is aided by an advance movement of the caterpillar track in the opposite direction of rotation [fr

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…

Robotic fish tracking method based on suboptimal interval Kalman filter

Science.gov (United States)

Tong, Xiaohong; Tang, Chao

2017-11-01

Autonomous Underwater Vehicle (AUV) research focused on tracking and positioning, precise guidance and return to dock and other fields. The robotic fish of AUV has become a hot application in intelligent education, civil and military etc. In nonlinear tracking analysis of robotic fish, which was found that the interval Kalman filter algorithm contains all possible filter results, but the range is wide, relatively conservative, and the interval data vector is uncertain before implementation. This paper proposes a ptimization algorithm of suboptimal interval Kalman filter. Suboptimal interval Kalman filter scheme used the interval inverse matrix with its worst inverse instead, is more approximate nonlinear state equation and measurement equation than the standard interval Kalman filter, increases the accuracy of the nominal dynamic system model, improves the speed and precision of tracking system. Monte-Carlo simulation results show that the optimal trajectory of sub optimal interval Kalman filter algorithm is better than that of the interval Kalman filter method and the standard method of the filter.

Food Delivery System with the Utilization of Vehicle Using Geographical Information System (GIS) and A Star Algorithm

Science.gov (United States)

Siregar, B.; Gunawan, D.; Andayani, U.; Sari Lubis, Elita; Fahmi, F.

2017-01-01

Food delivery system is one kind of geographical information systems (GIS) that can be applied through digitation process. The main case in food delivery system is the way to determine the shortest path and food delivery vehicle movement tracking. Therefore, to make sure that the digitation process of food delivery system can be applied efficiently, it is needed to add shortest path determination facility and food delivery vehicle tracking. This research uses A Star (A*) algorithm for determining shortest path and location-based system (LBS) programming for moving food delivery vehicle object tracking. According to this research, it is generated the integrated system that can be used by food delivery driver, customer, and administrator in terms of simplifying the food delivery system. Through the application of shortest path and the tracking of moving vehicle, thus the application of food delivery system in the scope of geographical information system (GIS) can be executed.

Formation Flying/Satellite Swarm Concept Project