A Low-Cost, High-Precision Navigator, Phase II
National Aeronautics and Space Administration — Toyon Research Corporation proposes to develop and demonstrate a prototype low-cost precision navigation system using commercial-grade gyroscopes and accelerometers....
Hybrid Transverse Polar Navigation for High-Precision and Long-Term INSs.
Wu, Ruonan; Wu, Qiuping; Han, Fengtian; Zhang, Rong; Hu, Peida; Li, Haixia
2018-05-12
Transverse navigation has been proposed to help inertial navigation systems (INSs) fill the gap of polar navigation ability. However, as the transverse system does not have the ability of navigate globally, a complicated switch between the transverse and the traditional algorithms is necessary when the system moves across the polar circles. To maintain the inner continuity and consistency of the core algorithm, a hybrid transverse polar navigation is proposed in this research based on a combination of Earth-fixed-frame mechanization and transverse-frame outputs. Furthermore, a thorough analysis of kinematic error characteristics, proper damping technology and corresponding long-term contributions of main error sources is conducted for the high-precision INSs. According to the analytical expressions of the long-term navigation errors in polar areas, the 24-h period symmetrical oscillation with a slowly divergent amplitude dominates the transverse horizontal position errors, and the first-order drift dominates the transverse azimuth error, which results from the gyro drift coefficients that occur in corresponding directions. Simulations are conducted to validate the theoretical analysis and the deduced analytical expressions. The results show that the proposed hybrid transverse navigation can ensure the same accuracy and oscillation characteristics in polar areas as the traditional algorithm in low and mid latitude regions.
Establishment of high-precision navigation system in the Republic of Armenia
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Manukyan Larisa Vladimirovna
2015-04-01
Full Text Available Medium-Earth orbit satellite systems make it possible to provide services on time coordination and navigation support for a wide range of consumers. At present, there are global navigation satellite systems GLONASS (Russia and GPS (USA. Users of these systems have an opportunity to determine their location accurately with the given characteristics of their navigation devices. In all developed countries the progress of geodesy and cartography is closely related to the implementation of advanced new technologies in both scientific and industrial areas. The introduction of new technologies and equipment in production is essential for the development of geodesy and cartography, bringing the existing geodetic networks and cartographic materials to modern condition. In the Republic of Armenia there are also plans on introduction of the systems for monitoring and management of vehicles for various purposes, as well as it is proposed to establish and implement an effective satellite navigation system to monitor and control traffic on the basis of advanced satellite technology. The article describes the basic steps to create the network of reference stations, GPS, aerial photography of much of the territory of Armenia, the creation of digital terrain model and the new maps by orthophotoplans. The analysis of the materials were carried out, on the basis of which in the Republic in 2015 a high-precision navigation system will be created. Due to the hard work of surveyors, cartographers and topographers the Republic was brought to European states level.
The PPP Precision Analysis Based on BDS Regional Navigation System
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ZHU Yongxing
2015-04-01
Full Text Available BeiDou navigation satellite system(BDS has opened service in most of the Asia-Pacific region, it offers the possibility to break the technological monopoly of GPS in the field of high-precision applications, so its performance of precise point positioning (PPP has been a great concern. Firstly, the constellation of BeiDou regional navigation system and BDS/GPS tracking network is introduced. Secondly, the precise ephemeris and clock offset accuracy of BeiDou satellite based on domestic tracking network is analyzed. Finally, the static and kinematic PPP accuracy is studied, and compared with the GPS. The actual measured numerical example shows that the static and kinematic PPP based on BDS can achieve centimeter-level and decimeter-level respectively, reaching the current level of GPS precise point positioning.
Gravity Compensation Using EGM2008 for High-Precision Long-Term Inertial Navigation Systems
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Ruonan Wu
2016-12-01
Full Text Available The gravity disturbance vector is one of the major error sources in high-precision and long-term inertial navigation applications. Specific to the inertial navigation systems (INSs with high-order horizontal damping networks, analyses of the error propagation show that the gravity-induced errors exist almost exclusively in the horizontal channels and are mostly caused by deflections of the vertical (DOV. Low-frequency components of the DOV propagate into the latitude and longitude errors at a ratio of 1:1 and time-varying fluctuations in the DOV excite Schuler oscillation. This paper presents two gravity compensation methods using the Earth Gravitational Model 2008 (EGM2008, namely, interpolation from the off-line database and computing gravity vectors directly using the spherical harmonic model. Particular attention is given to the error contribution of the gravity update interval and computing time delay. It is recommended for the marine navigation that a gravity vector should be calculated within 1 s and updated every 100 s at most. To meet this demand, the time duration of calculating the current gravity vector using EGM2008 has been reduced to less than 1 s by optimizing the calculation procedure. A few off-line experiments were conducted using the data of a shipborne INS collected during an actual sea test. With the aid of EGM2008, most of the low-frequency components of the position errors caused by the gravity disturbance vector have been removed and the Schuler oscillation has been attenuated effectively. In the rugged terrain, the horizontal position error could be reduced at best 48.85% of its regional maximum. The experimental results match with the theoretical analysis and indicate that EGM2008 is suitable for gravity compensation of the high-precision and long-term INSs.
Gravity Compensation Using EGM2008 for High-Precision Long-Term Inertial Navigation Systems.
Wu, Ruonan; Wu, Qiuping; Han, Fengtian; Liu, Tianyi; Hu, Peida; Li, Haixia
2016-12-18
The gravity disturbance vector is one of the major error sources in high-precision and long-term inertial navigation applications. Specific to the inertial navigation systems (INSs) with high-order horizontal damping networks, analyses of the error propagation show that the gravity-induced errors exist almost exclusively in the horizontal channels and are mostly caused by deflections of the vertical (DOV). Low-frequency components of the DOV propagate into the latitude and longitude errors at a ratio of 1:1 and time-varying fluctuations in the DOV excite Schuler oscillation. This paper presents two gravity compensation methods using the Earth Gravitational Model 2008 (EGM2008), namely, interpolation from the off-line database and computing gravity vectors directly using the spherical harmonic model. Particular attention is given to the error contribution of the gravity update interval and computing time delay. It is recommended for the marine navigation that a gravity vector should be calculated within 1 s and updated every 100 s at most. To meet this demand, the time duration of calculating the current gravity vector using EGM2008 has been reduced to less than 1 s by optimizing the calculation procedure. A few off-line experiments were conducted using the data of a shipborne INS collected during an actual sea test. With the aid of EGM2008, most of the low-frequency components of the position errors caused by the gravity disturbance vector have been removed and the Schuler oscillation has been attenuated effectively. In the rugged terrain, the horizontal position error could be reduced at best 48.85% of its regional maximum. The experimental results match with the theoretical analysis and indicate that EGM2008 is suitable for gravity compensation of the high-precision and long-term INSs.
Application of the spherical harmonic gravity model in high precision inertial navigation systems
International Nuclear Information System (INIS)
Wang, Jing; Yang, Gongliu; Zhou, Xiao; Li, Xiangyun
2016-01-01
The spherical harmonic gravity model (SHM) may, in general, be considered as a suitable alternative to the normal gravity model (NGM), because it represents the Earth’s gravitational field more accurately. However, the high-resolution SHM has never been used in current inertial navigation systems (INSs) due to its extremely complex expression. In this paper, the feasibility and accuracy of a truncated SHM are discussed for application in a real-time free-INS with a precision demand better than 0.8 nm h −1 . In particular, the time and space complexity are analyzed mathematically to verify the feasibility of the SHM. Also, a test on a typical navigation computer shows a storable range of cut-off degrees. To further evaluate the appropriate degree and accuracy of the truncated SHM, analyses of covariance and truncation error are proposed. Finally, a SHM of degree 12 is demonstrated to be the appropriate model for routine INSs in the precision range of 0.4–0.75 nm h −1 . Flight simulations and road tests show its outstanding performance over the traditional NGM. (paper)
Precise Point Positioning with the BeiDou Navigation Satellite System
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Min Li
2014-01-01
Full Text Available By the end of 2012, China had launched 16 BeiDou-2 navigation satellites that include six GEOs, five IGSOs and five MEOs. This has provided initial navigation and precise pointing services ability in the Asia-Pacific regions. In order to assess the navigation and positioning performance of the BeiDou-2 system, Wuhan University has built up a network of BeiDou Experimental Tracking Stations (BETS around the World. The Position and Navigation Data Analyst (PANDA software was modified to determine the orbits of BeiDou satellites and provide precise orbit and satellite clock bias products from the BeiDou satellite system for user applications. This article uses the BeiDou/GPS observations of the BeiDou Experimental Tracking Stations to realize the BeiDou and BeiDou/GPS static and kinematic precise point positioning (PPP. The result indicates that the precision of BeiDou static and kinematic PPP reaches centimeter level. The precision of BeiDou/GPS kinematic PPP solutions is improved significantly compared to that of BeiDou-only or GPS-only kinematic PPP solutions. The PPP convergence time also decreases with the use of combined BeiDou/GPS systems.
Precise point positioning with the BeiDou navigation satellite system.
Li, Min; Qu, Lizhong; Zhao, Qile; Guo, Jing; Su, Xing; Li, Xiaotao
2014-01-08
By the end of 2012, China had launched 16 BeiDou-2 navigation satellites that include six GEOs, five IGSOs and five MEOs. This has provided initial navigation and precise pointing services ability in the Asia-Pacific regions. In order to assess the navigation and positioning performance of the BeiDou-2 system, Wuhan University has built up a network of BeiDou Experimental Tracking Stations (BETS) around the World. The Position and Navigation Data Analyst (PANDA) software was modified to determine the orbits of BeiDou satellites and provide precise orbit and satellite clock bias products from the BeiDou satellite system for user applications. This article uses the BeiDou/GPS observations of the BeiDou Experimental Tracking Stations to realize the BeiDou and BeiDou/GPS static and kinematic precise point positioning (PPP). The result indicates that the precision of BeiDou static and kinematic PPP reaches centimeter level. The precision of BeiDou/GPS kinematic PPP solutions is improved significantly compared to that of BeiDou-only or GPS-only kinematic PPP solutions. The PPP convergence time also decreases with the use of combined BeiDou/GPS systems.
A Dynamic Precision Evaluation Method for the Star Sensor in the Stellar-Inertial Navigation System.
Lu, Jiazhen; Lei, Chaohua; Yang, Yanqiang
2017-06-28
Integrating the advantages of INS (inertial navigation system) and the star sensor, the stellar-inertial navigation system has been used for a wide variety of applications. The star sensor is a high-precision attitude measurement instrument; therefore, determining how to validate its accuracy is critical in guaranteeing its practical precision. The dynamic precision evaluation of the star sensor is more difficult than a static precision evaluation because of dynamic reference values and other impacts. This paper proposes a dynamic precision verification method of star sensor with the aid of inertial navigation device to realize real-time attitude accuracy measurement. Based on the gold-standard reference generated by the star simulator, the altitude and azimuth angle errors of the star sensor are calculated for evaluation criteria. With the goal of diminishing the impacts of factors such as the sensors' drift and devices, the innovative aspect of this method is to employ static accuracy for comparison. If the dynamic results are as good as the static results, which have accuracy comparable to the single star sensor's precision, the practical precision of the star sensor is sufficiently high to meet the requirements of the system specification. The experiments demonstrate the feasibility and effectiveness of the proposed method.
Application of high-precision two-way ranging to Galileo Earth-1 encounter navigation
Pollmeier, V. M.; Thurman, S. W.
1992-01-01
The application of precision two-way ranging to orbit determination with relatively short data arcs is investigated for the Galileo spacecraft's approach to its first Earth encounter (December 8, 1990). Analysis of previous S-band (2.3-GHz) ranging data acquired from Galileo indicated that under good signal conditions submeter precision and 10-m ranging accuracy were achieved. It is shown that ranging data of sufficient accuracy, when acquired from multiple stations, can sense the geocentric angular position of a distant spacecraft. A range data filtering technique, in which explicit modeling of range measurement bias parameters for each station pass is utilized, is shown to largely remove the systematic ground system calibration errors and transmission media effects from the Galileo range measurements, which would otherwise corrupt the angle-finding capabilities of the data. The accuracy of the Galileo orbit solutions obtained with S-band Doppler and precision ranging were found to be consistent with simple theoretical calculations, which predicted that angular accuracies of 0.26-0.34 microrad were achievable. In addition, the navigation accuracy achieved with precision ranging was marginally better than that obtained using delta-differenced one-way range (delta DOR), the principal data type that was previously used to obtain spacecraft angular position measurements operationally.
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Olha Sushchenko
2017-11-01
Full Text Available Purpose: The paper focuses on problems of design of robust precision attitude and heading reference systems, which can be applied in navigation of marine vehicles. The main goal is to create the optimization procedures for design of navigation and stabilization loops of the multimode gimballed system. The optimization procedure of the navigation loop design is based on the parametric robust H2/H∞-optimization. The optimization procedure of the stabilization loop design is based on the robust structural H∞-synthesis. Methods: To solve the given problem the methods of the robust control system theory and optimization methods are used. Results: The kinematical scheme of the precision gimballed attitude and heading reference system is represented. The parametrical optimization algorithm taking into consideration features of the researched system is given. Method of the mixed sensitivity relative to the researched system design is analyzed. Coefficients of the control laws of navigation loops are obtained based on optimization procedure providing compromise between accuracy and robustness. The robust controller of the stabilization loop was developed based on robust structural synthesis using method of the mixed sensitivity. Simulation of navigation and stabilization processes is carried out. Conclusions: The represented results prove efficiency of the proposed procedures, which can be useful for design of precision navigation systems of the moving vehicles.
Pollmeier, Vincent M.; Kallemeyn, Pieter H.; Thurman, Sam W.
1993-01-01
The application of high-accuracy S/S-band (2.1 GHz uplink/2.3 GHz downlink) ranging to orbit determination with relatively short data arcs is investigated for the approach phase of each of the Galileo spacecraft's two Earth encounters (8 December 1990 and 8 December 1992). Analysis of S-band ranging data from Galileo indicated that under favorable signal levels, meter-level precision was attainable. It is shown that ranginging data of sufficient accuracy, when acquired from multiple stations, can sense the geocentric angular position of a distant spacecraft. Explicit modeling of ranging bias parameters for each station pass is used to largely remove systematic ground system calibration errors and transmission media effects from the Galileo range measurements, which would otherwise corrupt the angle finding capabilities of the data. The accuracy achieved using the precision range filtering strategy proved markedly better when compared to post-flyby reconstructions than did solutions utilizing a traditional Doppler/range filter strategy. In addition, the navigation accuracy achieved with precision ranging was comparable to that obtained using delta-Differenced One-Way Range, an interferometric measurement of spacecraft angular position relative to a natural radio source, which was also used operationally.
Kolarik, Branden S; Baer, Trevor; Shahlaie, Kiarash; Yonelinas, Andrew P; Ekstrom, Arne D
2018-01-01
Increasing evidence suggests that the human hippocampus contributes to a range of different behaviors, including episodic memory, language, short-term memory, and navigation. A novel theoretical framework, the Precision and Binding Model, accounts for these phenomenon by describing a role for the hippocampus in high-resolution, complex binding. Other theories like Cognitive Map Theory, in contrast, predict a specific role for the hippocampus in allocentric navigation, while Declarative Memory Theory predicts a specific role in delay-dependent conscious memory. Navigation provides a unique venue for testing these predictions, with past results from research with humans providing inconsistent findings regarding the role of the human hippocampus in spatial navigation. Here, we tested five patients with lesions primarily restricted to the hippocampus and those extending out into the surrounding medial temporal lobe cortex on a virtual water maze task. Consistent with the Precision and Binding Model, we found partially intact allocentric memory in all patients, with impairments in the spatial precision of their searches for a hidden target. We found similar impairments at both immediate and delayed testing. Our findings are consistent with the Precision and Binding Model of hippocampal function, arguing for its role across domains in high-resolution, complex binding. Remembering goal locations in one's environment is a critical skill for survival. How this information is represented in the brain is still not fully understood, but is believed to rely in some capacity on structures in the medial temporal lobe. Contradictory findings from studies of both humans and animals have been difficult to reconcile with regard to the role of the MTL, specifically the hippocampus. By assessing impairments observed during navigation to a goal in patients with medial temporal lobe damage we can better understand the role these structures play in such behavior. Utilizing virtual reality
Yong-Jin Yoon; King Ho Holden Li; Jiahe Steven Lee; Woo-Tae Park
2015-01-01
Global Positioning System and Inertial Navigation System can be used to determine position and velocity. A Global Positioning System module is able to accurately determine position without sensor drift, but its usage is limited in heavily urbanized environments and heavy vegetation. While high-cost tactical-grade Inertial Navigation System can determine position accurately, low-cost micro-electro-mechanical system Inertial Navigation System sensors are plagued by significant errors. Global Po...
Determination of UAV position using high accuracy navigation platform
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Ireneusz Kubicki
2016-07-01
Full Text Available The choice of navigation system for mini UAV is very important because of its application and exploitation, particularly when the installed on it a synthetic aperture radar requires highly precise information about an object’s position. The presented exemplary solution of such a system draws attention to the possible problems associated with the use of appropriate technology, sensors, and devices or with a complete navigation system. The position and spatial orientation errors of the measurement platform influence on the obtained SAR imaging. Both, turbulences and maneuvers performed during flight cause the changes in the position of the airborne object resulting in deterioration or lack of images from SAR. Consequently, it is necessary to perform operations for reducing or eliminating the impact of the sensors’ errors on the UAV position accuracy. You need to look for compromise solutions between newer better technologies and in the field of software. Keywords: navigation systems, unmanned aerial vehicles, sensors integration
Li, Xingxing; Zhang, Xiaohong; Ren, Xiaodong; Fritsche, Mathias; Wickert, Jens; Schuh, Harald
2015-02-09
The world of satellite navigation is undergoing dramatic changes with the rapid development of multi-constellation Global Navigation Satellite Systems (GNSSs). At the moment more than 70 satellites are already in view, and about 120 satellites will be available once all four systems (BeiDou + Galileo + GLONASS + GPS) are fully deployed in the next few years. This will bring great opportunities and challenges for both scientific and engineering applications. In this paper we develop a four-system positioning model to make full use of all available observations from different GNSSs. The significant improvement of satellite visibility, spatial geometry, dilution of precision, convergence, accuracy, continuity and reliability that a combining utilization of multi-GNSS brings to precise positioning are carefully analyzed and evaluated, especially in constrained environments.
Zhang, Pengfei; Zhang, Rui; Liu, Jinhai; Lu, Xiaochun
2018-01-01
This study proposes two models for precise time transfer using the BeiDou Navigation Satellite System triple-frequency signals: ionosphere-free (IF) combined precise point positioning (PPP) model with two dual-frequency combinations (IF-PPP1) and ionosphere-free combined PPP model with a single triple-frequency combination (IF-PPP2). A dataset with a short baseline (with a common external time frequency) and a long baseline are used for performance assessments. The results show that IF-PPP1 and IF-PPP2 models can both be used for precise time transfer using BeiDou Navigation Satellite System (BDS) triple-frequency signals, and the accuracy and stability of time transfer is the same in both cases, except for a constant system bias caused by the hardware delay of different frequencies, which can be removed by the parameter estimation and prediction with long time datasets or by a priori calibration. PMID:29596330
Precision Landing and Hazard Avoidance Doman
Robertson, Edward A.; Carson, John M., III
2016-01-01
The Precision Landing and Hazard Avoidance (PL&HA) domain addresses the development, integration, testing, and spaceflight infusion of sensing, processing, and GN&C functions critical to the success and safety of future human and robotic exploration missions. PL&HA sensors also have applications to other mission events, such as rendezvous and docking. Autonomous PL&HA builds upon the core GN&C capabilities developed to enable soft, controlled landings on the Moon, Mars, and other solar system bodies. Through the addition of a Terrain Relative Navigation (TRN) function, precision landing within tens of meters of a map-based target is possible. The addition of a 3-D terrain mapping lidar sensor improves the probability of a safe landing via autonomous, real-time Hazard Detection and Avoidance (HDA). PL&HA significantly improves the probability of mission success and enhances access to sites of scientific interest located in challenging terrain. PL&HA can also utilize external navigation aids, such as navigation satellites and surface beacons. Advanced Lidar Sensors High precision ranging, velocimetry, and 3-D terrain mapping Terrain Relative Navigation (TRN) TRN compares onboard reconnaissance data with real-time terrain imaging data to update the S/C position estimate Hazard Detection and Avoidance (HDA) Generates a high-resolution, 3-D terrain map in real-time during the approach trajectory to identify safe landing targets Inertial Navigation During Terminal Descent High precision surface relative sensors enable accurate inertial navigation during terminal descent and a tightly controlled touchdown within meters of the selected safe landing target.
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Rui Tu
2018-03-01
Full Text Available This study proposes two models for precise time transfer using the BeiDou Navigation Satellite System triple-frequency signals: ionosphere-free (IF combined precise point positioning (PPP model with two dual-frequency combinations (IF-PPP1 and ionosphere-free combined PPP model with a single triple-frequency combination (IF-PPP2. A dataset with a short baseline (with a common external time frequency and a long baseline are used for performance assessments. The results show that IF-PPP1 and IF-PPP2 models can both be used for precise time transfer using BeiDou Navigation Satellite System (BDS triple-frequency signals, and the accuracy and stability of time transfer is the same in both cases, except for a constant system bias caused by the hardware delay of different frequencies, which can be removed by the parameter estimation and prediction with long time datasets or by a priori calibration.
Clinical applications of virtual navigation bronchial intervention.
Kajiwara, Naohiro; Maehara, Sachio; Maeda, Junichi; Hagiwara, Masaru; Okano, Tetsuya; Kakihana, Masatoshi; Ohira, Tatsuo; Kawate, Norihiko; Ikeda, Norihiko
2018-01-01
In patients with bronchial tumors, we frequently consider endoscopic treatment as the first treatment of choice. All computed tomography (CT) must satisfy several conditions necessary to analyze images by Synapse Vincent. To select safer and more precise approaches for patients with bronchial tumors, we determined the indications and efficacy of virtual navigation intervention for the treatment of bronchial tumors. We examined the efficacy of virtual navigation bronchial intervention for the treatment of bronchial tumors located at a variety of sites in the tracheobronchial tree using a high-speed 3-dimensional (3D) image analysis system, Synapse Vincent. Constructed images can be utilized to decide on the simulation and interventional strategy as well as for navigation during interventional manipulation in two cases. Synapse Vincent was used to determine the optimal planning of virtual navigation bronchial intervention. Moreover, this system can detect tumor location and alsodepict surrounding tissues, quickly, accurately, and safely. The feasibility and safety of Synapse Vincent in performing useful preoperative simulation and navigation of surgical procedures can lead to safer, more precise, and less invasion for the patient, and makes it easy to construct an image, depending on the purpose, in 5-10 minutes using Synapse Vincent. Moreover, if the lesion is in the parenchyma or sub-bronchial lumen, it helps to perform simulation with virtual skeletal subtraction to estimate potential lesion movement. By using virtual navigation system for simulation, bronchial intervention was performed with no complications safely and precisely. Preoperative simulation using virtual navigation bronchial intervention reduces the surgeon's stress levels, particularly when highly skilled techniques are needed to operate on lesions. This task, including both preoperative simulation and intraoperative navigation, leads to greater safety and precision. These technological instruments
A Police and Insurance Joint Management System Based on High Precision BDS/GPS Positioning
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Wenwei Zuo
2018-01-01
Full Text Available Car ownership in China reached 194 million vehicles at the end of 2016. The traffic congestion index (TCI exceeds 2.0 during rush hour in some cities. Inefficient processing for minor traffic accidents is considered to be one of the leading causes for road traffic jams. Meanwhile, the process after an accident is quite troublesome. The main reason is that it is almost always impossible to get the complete chain of evidence when the accident happens. Accordingly, a police and insurance joint management system is developed which is based on high precision BeiDou Navigation Satellite System (BDS/Global Positioning System (GPS positioning to process traffic accidents. First of all, an intelligent vehicle rearview mirror terminal is developed. The terminal applies a commonly used consumer electronic device with single frequency navigation. Based on the high precision BDS/GPS positioning algorithm, its accuracy can reach sub-meter level in the urban areas. More specifically, a kernel driver is built to realize the high precision positioning algorithm in an Android HAL layer. Thus the third-party application developers can call the general location Application Programming Interface (API of the original standard Global Navigation Satellite System (GNSS to get high precision positioning results. Therefore, the terminal can provide lane level positioning service for car users. Next, a remote traffic accident processing platform is built to provide big data analysis and management. According to the big data analysis of information collected by BDS high precision intelligent sense service, vehicle behaviors can be obtained. The platform can also automatically match and screen the data that uploads after an accident to achieve accurate reproduction of the scene. Thus, it helps traffic police and insurance personnel to complete remote responsibility identification and survey for the accident. Thirdly, a rapid processing flow is established in this article to
A Police and Insurance Joint Management System Based on High Precision BDS/GPS Positioning
Zuo, Wenwei; Guo, Chi; Liu, Jingnan; Peng, Xuan; Yang, Min
2018-01-01
Car ownership in China reached 194 million vehicles at the end of 2016. The traffic congestion index (TCI) exceeds 2.0 during rush hour in some cities. Inefficient processing for minor traffic accidents is considered to be one of the leading causes for road traffic jams. Meanwhile, the process after an accident is quite troublesome. The main reason is that it is almost always impossible to get the complete chain of evidence when the accident happens. Accordingly, a police and insurance joint management system is developed which is based on high precision BeiDou Navigation Satellite System (BDS)/Global Positioning System (GPS) positioning to process traffic accidents. First of all, an intelligent vehicle rearview mirror terminal is developed. The terminal applies a commonly used consumer electronic device with single frequency navigation. Based on the high precision BDS/GPS positioning algorithm, its accuracy can reach sub-meter level in the urban areas. More specifically, a kernel driver is built to realize the high precision positioning algorithm in an Android HAL layer. Thus the third-party application developers can call the general location Application Programming Interface (API) of the original standard Global Navigation Satellite System (GNSS) to get high precision positioning results. Therefore, the terminal can provide lane level positioning service for car users. Next, a remote traffic accident processing platform is built to provide big data analysis and management. According to the big data analysis of information collected by BDS high precision intelligent sense service, vehicle behaviors can be obtained. The platform can also automatically match and screen the data that uploads after an accident to achieve accurate reproduction of the scene. Thus, it helps traffic police and insurance personnel to complete remote responsibility identification and survey for the accident. Thirdly, a rapid processing flow is established in this article to meet the
A Police and Insurance Joint Management System Based on High Precision BDS/GPS Positioning.
Zuo, Wenwei; Guo, Chi; Liu, Jingnan; Peng, Xuan; Yang, Min
2018-01-10
Car ownership in China reached 194 million vehicles at the end of 2016. The traffic congestion index (TCI) exceeds 2.0 during rush hour in some cities. Inefficient processing for minor traffic accidents is considered to be one of the leading causes for road traffic jams. Meanwhile, the process after an accident is quite troublesome. The main reason is that it is almost always impossible to get the complete chain of evidence when the accident happens. Accordingly, a police and insurance joint management system is developed which is based on high precision BeiDou Navigation Satellite System (BDS)/Global Positioning System (GPS) positioning to process traffic accidents. First of all, an intelligent vehicle rearview mirror terminal is developed. The terminal applies a commonly used consumer electronic device with single frequency navigation. Based on the high precision BDS/GPS positioning algorithm, its accuracy can reach sub-meter level in the urban areas. More specifically, a kernel driver is built to realize the high precision positioning algorithm in an Android HAL layer. Thus the third-party application developers can call the general location Application Programming Interface (API) of the original standard Global Navigation Satellite System (GNSS) to get high precision positioning results. Therefore, the terminal can provide lane level positioning service for car users. Next, a remote traffic accident processing platform is built to provide big data analysis and management. According to the big data analysis of information collected by BDS high precision intelligent sense service, vehicle behaviors can be obtained. The platform can also automatically match and screen the data that uploads after an accident to achieve accurate reproduction of the scene. Thus, it helps traffic police and insurance personnel to complete remote responsibility identification and survey for the accident. Thirdly, a rapid processing flow is established in this article to meet the
High Precision GNSS Guidance for Field Mobile Robots
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Ladislav Jurišica
2012-11-01
Full Text Available In this paper, we discuss GNSS (Global Navigation Satellite System guidance for field mobile robots. Several GNSS systems and receivers, as well as multiple measurement methods and principles of GNSS systems are examined. We focus mainly on sources of errors and investigate diverse approaches for precise measuring and effective use of GNSS systems for real-time robot localization. The main body of the article compares two GNSS receivers and their measurement methods. We design, implement and evaluate several mathematical methods for precise robot localization.
Xiao, Mengli; Zhang, Yongbo; Fu, Huimin; Wang, Zhihua
2018-05-01
High-precision navigation algorithm is essential for the future Mars pinpoint landing mission. The unknown inputs caused by large uncertainties of atmospheric density and aerodynamic coefficients as well as unknown measurement biases may cause large estimation errors of conventional Kalman filters. This paper proposes a derivative-free version of nonlinear unbiased minimum variance filter for Mars entry navigation. This filter has been designed to solve this problem by estimating the state and unknown measurement biases simultaneously with derivative-free character, leading to a high-precision algorithm for the Mars entry navigation. IMU/radio beacons integrated navigation is introduced in the simulation, and the result shows that with or without radio blackout, our proposed filter could achieve an accurate state estimation, much better than the conventional unscented Kalman filter, showing the ability of high-precision Mars entry navigation algorithm. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.
Experimental study on the precise orbit determination of the BeiDou navigation satellite system.
He, Lina; Ge, Maorong; Wang, Jiexian; Wickert, Jens; Schuh, Harald
2013-03-01
The regional service of the Chinese BeiDou satellite navigation system is now in operation with a constellation including five Geostationary Earth Orbit satellites (GEO), five Inclined Geosynchronous Orbit (IGSO) satellites and four Medium Earth Orbit (MEO) satellites. Besides the standard positioning service with positioning accuracy of about 10 m, both precise relative positioning and precise point positioning are already demonstrated. As is well known, precise orbit and clock determination is essential in enhancing precise positioning services. To improve the satellite orbits of the BeiDou regional system, we concentrate on the impact of the tracking geometry and the involvement of MEOs, and on the effect of integer ambiguity resolution as well. About seven weeks of data collected at the BeiDou Experimental Test Service (BETS) network is employed in this experimental study. Several tracking scenarios are defined, various processing schemata are designed and carried out; and then, the estimates are compared and analyzed in detail. The results show that GEO orbits, especially the along-track component, can be significantly improved by extending the tracking network in China along longitude direction, whereas IGSOs gain more improvement if the tracking network extends in latitude. The involvement of MEOs and ambiguity-fixing also make the orbits better.
Jeon, S. M.; Jang, G. H.; Choi, H. C.; Park, S. H.; Park, J. O.
2012-04-01
Different magnetic navigation systems (MNSs) have been investigated for the wireless manipulation of microrobots in human blood vessels. Here we propose a MNS and methodology for generation of both the precise helical and translational motions of a microrobot to improve its maneuverability in complex human blood vessel. We then present experiments demonstrating the helical and translational motions of a spiral-type microrobot to verify the proposed MNS.
On-the-fly Locata/inertial navigation system integration for precise maritime application
Jiang, Wei; Li, Yong; Rizos, Chris
2013-10-01
The application of Global Navigation Satellite System (GNSS) technology has meant that marine navigators have greater access to a more consistent and accurate positioning capability than ever before. However, GNSS may not be able to meet all emerging navigation performance requirements for maritime applications with respect to service robustness, accuracy, integrity and availability. In particular, applications in port areas (for example automated docking) and in constricted waterways, have very stringent performance requirements. Even when an integrated inertial navigation system (INS)/GNSS device is used there may still be performance gaps. GNSS signals are easily blocked or interfered with, and sometimes the satellite geometry may not be good enough for high accuracy and high reliability applications. Furthermore, the INS accuracy degrades rapidly during GNSS outages. This paper investigates the use of a portable ground-based positioning system, known as ‘Locata’, which was integrated with an INS, to provide accurate navigation in a marine environment without reliance on GNSS signals. An ‘on-the-fly’ Locata resolution algorithm that takes advantage of geometry change via an extended Kalman filter is proposed in this paper. Single-differenced Locata carrier phase measurements are utilized to achieve accurate and reliable solutions. A ‘loosely coupled’ decentralized Locata/INS integration architecture based on the Kalman filter is used for data processing. In order to evaluate the system performance, a field trial was conducted on Sydney Harbour. A Locata network consisting of eight Locata transmitters was set up near the Sydney Harbour Bridge. The experiment demonstrated that the Locata on-the-fly (OTF) algorithm is effective and can improve the system accuracy in comparison with the conventional ‘known point initialization’ (KPI) method. After the OTF and KPI comparison, the OTF Locata/INS integration is then assessed further and its performance
On-the-fly Locata/inertial navigation system integration for precise maritime application
International Nuclear Information System (INIS)
Jiang, Wei; Li, Yong; Rizos, Chris
2013-01-01
The application of Global Navigation Satellite System (GNSS) technology has meant that marine navigators have greater access to a more consistent and accurate positioning capability than ever before. However, GNSS may not be able to meet all emerging navigation performance requirements for maritime applications with respect to service robustness, accuracy, integrity and availability. In particular, applications in port areas (for example automated docking) and in constricted waterways, have very stringent performance requirements. Even when an integrated inertial navigation system (INS)/GNSS device is used there may still be performance gaps. GNSS signals are easily blocked or interfered with, and sometimes the satellite geometry may not be good enough for high accuracy and high reliability applications. Furthermore, the INS accuracy degrades rapidly during GNSS outages. This paper investigates the use of a portable ground-based positioning system, known as ‘Locata’, which was integrated with an INS, to provide accurate navigation in a marine environment without reliance on GNSS signals. An ‘on-the-fly’ Locata resolution algorithm that takes advantage of geometry change via an extended Kalman filter is proposed in this paper. Single-differenced Locata carrier phase measurements are utilized to achieve accurate and reliable solutions. A ‘loosely coupled’ decentralized Locata/INS integration architecture based on the Kalman filter is used for data processing. In order to evaluate the system performance, a field trial was conducted on Sydney Harbour. A Locata network consisting of eight Locata transmitters was set up near the Sydney Harbour Bridge. The experiment demonstrated that the Locata on-the-fly (OTF) algorithm is effective and can improve the system accuracy in comparison with the conventional ‘known point initialization’ (KPI) method. After the OTF and KPI comparison, the OTF Locata/INS integration is then assessed further and its performance
Jung, Jaewoo; Swenson, Harry; Thipphavong, Jane; Martin, Lynne Hazel; Chen, Liang; Nguyen, Jimmy
2013-01-01
The growth of global demand for air transportation has put increasing strain on the nation's air traffic management system. To relieve this strain, the International Civil Aviation Organization has urged all nations to adopt Performance-Based Navigation (PBN), which can help to reduce air traffic congestion, decrease aviation fuel consumption, and protect the environment. NASA has developed a Terminal Area Precision Scheduling and Spacing (TAPSS) system that can support increased use of PBN during periods of high traffic, while supporting fuel-efficient, continuous descent approaches. In the original development of this system, arrival aircraft are assigned fuel-efficient Area Navigation (RNAV) Standard Terminal Arrival Routes before their initial descent from cruise, with routing defined to a specific runway. The system also determines precise schedules for these aircraft that facilitate continuous descent through the assigned routes. To meet these schedules, controllers are given a set of advisory tools to precisely control aircraft. The TAPSS system has been evaluated in a series of human-in-the-loop (HITL) air traffic simulations during 2010 and 2011. Results indicated increased airport arrival throughput up to 10 over current operations, and maintained fuel-efficient aircraft decent profiles from the initial descent to landing with reduced controller workload. This paper focuses on results from a joint NASA and FAA HITL simulation conducted in 2012. Due to the FAA rollout of the advance terminal area PBN procedures at mid-sized airports first, the TAPSS system was modified to manage arrival aircraft as they entered Terminal Radar Approach Control (TRACON). Dallas-Love Field airport (DAL) was selected by the FAA as a representative mid-sized airport within a constrained TRACON airspace due to the close proximity of a major airport, in this case Dallas-Ft Worth International Airport, one of the busiest in the world. To address this constraint, RNAV routes and
Magnetic navigation and tracking of underwater vehicles
Digital Repository Service at National Institute of Oceanography (India)
Teixeira, F.C.; Pascoal, A.M.
for the navigation of AUVs has been proposed many years ago but the concept still requires practical demonstration. Implementation issues One of the advantages of mag- netic navigation consists in being passive and economical in terms of energy. Magnetic sensors do... like the present one, that require magnetic measurements with very high precision. A typical solution to this problem consists in the placement of magnetic sensors as far away as possible from the sources of noise but this may not be practical...
Cloud Absorption Radiometer Autonomous Navigation System - CANS
Kahle, Duncan; Gatebe, Charles; McCune, Bill; Hellwig, Dustan
2013-01-01
, the software aligns the precision navigation sensors and initializes the communications interfaces with the sensor and the remote computing system. It also monitors the navigation data state for quality and ensures that the system maintains the required fidelity for attitude and positional information. In the operational mode, the software runs at 12.5 Hz and gathers the required navigation/attitude data, computes the required sensor correction values, and then commands the sensor to the required roll correction. In this manner, the sensor will stay very near to vertical at all times, greatly improving the resulting collected data and imagery. CANS greatly improves quality of resulting imagery and data collected. In addition, the software component of the system outputs a concisely formatted, high-speed data stream that can be used for further science data processing. This precision, time-stamped data also can benefit other instruments on the same aircraft platform by providing extra information from the mission flight.
Improved artificial bee colony algorithm based gravity matching navigation method.
Gao, Wei; Zhao, Bo; Zhou, Guang Tao; Wang, Qiu Ying; Yu, Chun Yang
2014-07-18
Gravity matching navigation algorithm is one of the key technologies for gravity aided inertial navigation systems. With the development of intelligent algorithms, the powerful search ability of the Artificial Bee Colony (ABC) algorithm makes it possible to be applied to the gravity matching navigation field. However, existing search mechanisms of basic ABC algorithms cannot meet the need for high accuracy in gravity aided navigation. Firstly, proper modifications are proposed to improve the performance of the basic ABC algorithm. Secondly, a new search mechanism is presented in this paper which is based on an improved ABC algorithm using external speed information. At last, modified Hausdorff distance is introduced to screen the possible matching results. Both simulations and ocean experiments verify the feasibility of the method, and results show that the matching rate of the method is high enough to obtain a precise matching position.
Gelin, Chrystel
2013-01-01
Dead-Reckoning aided with Doppler velocity measurement has been the most common method for underwater navigation for small vehicles. Unfortunately DR requires frequent position recalibrations and underwater vehicle navigation systems are limited to periodic position update when they surface. Finally standard Global Positioning System (GPS) receivers are unable to provide the rate or precision required when used on a small vessel. To overcome this, a low cost high rate motion measurement system for an Unmanned Surface Vehicle (USV) with underwater and oceanographic purposes is proposed. The proposed onboard system for the USV consists of an Inertial Measurement Unit (IMU) with accelerometers and rate gyros, a GPS receiver, a flux-gate compass, a roll and tilt sensor and an ADCP. Interfacing all the sensors proved rather challenging because of their different characteristics. The proposed data fusion technique integrates the sensors and develops an embeddable software package, using real time data fusion method...
Juvenile Osprey Navigation during Trans-Oceanic Migration.
Directory of Open Access Journals (Sweden)
Travis W Horton
Full Text Available To compensate for drift, an animal migrating through air or sea must be able to navigate. Although some species of bird, fish, insect, mammal, and reptile are capable of drift compensation, our understanding of the spatial reference frame, and associated coordinate space, in which these navigational behaviors occur remains limited. Using high resolution satellite-monitored GPS track data, we show that juvenile ospreys (Pandion haliaetus are capable of non-stop constant course movements over open ocean spanning distances in excess of 1500 km despite the perturbing effects of winds and the lack of obvious landmarks. These results are best explained by extreme navigational precision in an exogenous spatio-temporal reference frame, such as positional orientation relative to Earth's magnetic field and pacing relative to an exogenous mechanism of keeping time. Given the age (<1 year-old of these birds and knowledge of their hatching site locations, we were able to transform Enhanced Magnetic Model coordinate locations such that the origin of the magnetic coordinate space corresponded with each bird's nest. Our analyses show that trans-oceanic juvenile osprey movements are consistent with bicoordinate positional orientation in transformed magnetic coordinate or geographic space. Through integration of movement and meteorological data, we propose a new theoretical framework, chord and clock navigation, capable of explaining the precise spatial orientation and temporal pacing performed by juvenile ospreys during their long-distance migrations over open ocean.
Improved Line Tracking System for Autonomous Navigation of High-Speed Vehicle
Directory of Open Access Journals (Sweden)
Yahya Zare Khafri
2012-07-01
Full Text Available Line tracking navigation is one of the most widely techniques used in the robot navigation. In this paper, a customized line tracking system is proposed for autonomous navigation of high speed vehicles. In the presented system, auxiliary information -in addition to the road path- is added to the tracking lines such as locations of turn and intersections in the real roads. Moreover, the geometric position of line sensors is re-designed enables the high rate sensing with higher reliability. Finally, a light-weight navigation algorithm is proposed allow the high-speed movement using a reasonable processing power. This system is implemented on a MIPS-based embedded processor and experimental results with this embedded system show more than 98% accuracy at 200km/h with a 1GHz processor is viable.
Precision Airdrop (Largage de precision)
2005-12-01
NAVIGATION TO A PRECISION AIRDROP OVERVIEW RTO-AG-300-V24 2 - 9 the point from various compass headings. As the tests are conducted, the resultant...rate. This approach avoids including a magnetic compass for the heading reference, which has difficulties due to local changes in the magnetic field...Scientifica della Difesa ROYAUME-UNI Via XX Settembre 123 Dstl Knowledge Services ESPAGNE 00187 Roma Information Centre, Building 247 SDG TECEN / DGAM
Visual navigation using edge curve matching for pinpoint planetary landing
Cui, Pingyuan; Gao, Xizhen; Zhu, Shengying; Shao, Wei
2018-05-01
Pinpoint landing is challenging for future Mars and asteroid exploration missions. Vision-based navigation scheme based on feature detection and matching is practical and can achieve the required precision. However, existing algorithms are computationally prohibitive and utilize poor-performance measurements, which pose great challenges for the application of visual navigation. This paper proposes an innovative visual navigation scheme using crater edge curves during descent and landing phase. In the algorithm, the edge curves of the craters tracked from two sequential images are utilized to determine the relative attitude and position of the lander through a normalized method. Then, considering error accumulation of relative navigation, a method is developed. That is to integrate the crater-based relative navigation method with crater-based absolute navigation method that identifies craters using a georeferenced database for continuous estimation of absolute states. In addition, expressions of the relative state estimate bias are derived. Novel necessary and sufficient observability criteria based on error analysis are provided to improve the navigation performance, which hold true for similar navigation systems. Simulation results demonstrate the effectiveness and high accuracy of the proposed navigation method.
Thongtan, Thayathip; Tirawanichakul, Pawit; Satirapod, Chalermchon
2017-12-01
Each GNSS constellation operates its own system times; namely, GPS system time (GPST), GLONASS system time (GLONASST), BeiDou system time (BDT) and Galileo system time (GST). They could be traced back to Coordinated Universal Time (UTC) scale and are aligned to GPST. This paper estimates the receiver clock offsets to three timescales: GPST, GLONASST and BDT. The two measurement scenarios use two identical multi-GNSS geodetic receivers connected to the same geodetic antenna through a splitter. One receiver is driven by its internal oscillators and another receiver is connected to the external frequency oscillators, caesium frequency standard, kept as the Thailand standard time scale at the National Institute of Metrology (Thailand) called UTC(NIMT). The three weeks data are observed at 30 seconds sample rate. The receiver clock offsets with respected to the three system time are estimated and analysed through the geodetic technique of static Precise Point Positioning (PPP) using a data processing software developed by Wuhan University - Positioning And Navigation Data Analyst (PANDA) software. The estimated receiver clock offsets are around 32, 33 and 18 nanoseconds from GPST, GLONASST and BDT respectively. This experiment is initially stated that each timescale is inter-operated with GPST and further measurements on receiver internal delay has to be determined for clock comparisons especially the high accuracy clock at timing laboratories.
An Imaging Sensor-Aided Vision Navigation Approach that Uses a Geo-Referenced Image Database.
Li, Yan; Hu, Qingwu; Wu, Meng; Gao, Yang
2016-01-28
In determining position and attitude, vision navigation via real-time image processing of data collected from imaging sensors is advanced without a high-performance global positioning system (GPS) and an inertial measurement unit (IMU). Vision navigation is widely used in indoor navigation, far space navigation, and multiple sensor-integrated mobile mapping. This paper proposes a novel vision navigation approach aided by imaging sensors and that uses a high-accuracy geo-referenced image database (GRID) for high-precision navigation of multiple sensor platforms in environments with poor GPS. First, the framework of GRID-aided vision navigation is developed with sequence images from land-based mobile mapping systems that integrate multiple sensors. Second, a highly efficient GRID storage management model is established based on the linear index of a road segment for fast image searches and retrieval. Third, a robust image matching algorithm is presented to search and match a real-time image with the GRID. Subsequently, the image matched with the real-time scene is considered to calculate the 3D navigation parameter of multiple sensor platforms. Experimental results show that the proposed approach retrieves images efficiently and has navigation accuracies of 1.2 m in a plane and 1.8 m in height under GPS loss in 5 min and within 1500 m.
Directory of Open Access Journals (Sweden)
Jiayu Zhang
2018-05-01
Full Text Available The Semi-Strapdown Inertial Navigation System (SSINS provides a new solution to attitude measurement of a high-speed rotating missile. However, micro-electro-mechanical-systems (MEMS inertial measurement unit (MIMU outputs are corrupted by significant sensor errors. In order to improve the navigation precision, a rotation modulation technology method called Rotation Semi-Strapdown Inertial Navigation System (RSSINS is introduced into SINS. In fact, the stability of the modulation angular rate is difficult to achieve in a high-speed rotation environment. The changing rotary angular rate has an impact on the inertial sensor error self-compensation. In this paper, the influence of modulation angular rate error, including acceleration-deceleration process, and instability of the angular rate on the navigation accuracy of RSSINS is deduced and the error characteristics of the reciprocating rotation scheme are analyzed. A new compensation method is proposed to remove or reduce sensor errors so as to make it possible to maintain high precision autonomous navigation performance by MIMU when there is no external aid. Experiments have been carried out to validate the performance of the method. In addition, the proposed method is applicable for modulation angular rate error compensation under various dynamic conditions.
Fault-tolerant and Diagnostic Methods for Navigation
DEFF Research Database (Denmark)
Blanke, Mogens
2003-01-01
to diagnose faults and autonomously provide valid navigation data, disregarding any faulty sensor data and use sensor fusion to obtain a best estimate for users. This paper discusses how diagnostic and fault-tolerant methods are applicable in marine systems. An example chosen is sensor fusion for navigation......Precise and reliable navigation is crucial, and for reasons of safety, essential navigation instruments are often duplicated. Hardware redundancy is mostly used to manually switch between instruments should faults occur. In contrast, diagnostic methods are available that can use analytic redundancy...
Directory of Open Access Journals (Sweden)
LIU Weiping
2016-02-01
Full Text Available To resolve the high relativity between the transverse element of GEO orbit and double-difference ambiguity, the classical double-difference dynamic method is improved and the method, which is to determine precise BeiDou satellite orbit using carrier phase and pseudo-range smoothed by phase, is proposed. The feasibility of the method is discussed and the influence of the method about ambiguity fixing is analyzed. Considering the characteristic of BeiDou, the method, which is to fix double-difference ambiguity of BeiDou satellites by QIF, is derived. The real data analysis shows that the new method, which can reduce the relativity and assure the precision, is better than the classical double-difference dynamic method. The result of ambiguity fixing is well by QIF, but the ambiguity fixing success rate is not high on the whole. So the precision of BeiDou orbit can't be improved clearly after ambiguity fixing.
Doppler lidar sensor for precision navigation in GPS-deprived environment
Amzajerdian, F.; Pierrottet, D. F.; Hines, G. D.; Petway, L. B.; Barnes, B. W.
2013-05-01
Landing mission concepts that are being developed for exploration of solar system bodies are increasingly ambitious in their implementations and objectives. Most of these missions require accurate position and velocity data during their descent phase in order to ensure safe, soft landing at the pre-designated sites. Data from the vehicle's Inertial Measurement Unit will not be sufficient due to significant drift error after extended travel time in space. Therefore, an onboard sensor is required to provide the necessary data for landing in the GPS-deprived environment of space. For this reason, NASA Langley Research Center has been developing an advanced Doppler lidar sensor capable of providing accurate and reliable data suitable for operation in the highly constrained environment of space. The Doppler lidar transmits three laser beams in different directions toward the ground. The signal from each beam provides the platform velocity and range to the ground along the laser line-of-sight (LOS). The six LOS measurements are then combined in order to determine the three components of the vehicle velocity vector, and to accurately measure altitude and attitude angles relative to the local ground. These measurements are used by an autonomous Guidance, Navigation, and Control system to accurately navigate the vehicle from a few kilometers above the ground to the designated location and to execute a gentle touchdown. A prototype version of our lidar sensor has been completed for a closed-loop demonstration onboard a rocket-powered terrestrial free-flyer vehicle.
Quantum imaging for underwater arctic navigation
Lanzagorta, Marco
2017-05-01
The precise navigation of underwater vehicles is a difficult task due to the challenges imposed by the variable oceanic environment. It is particularly difficult if the underwater vehicle is trying to navigate under the Arctic ice shelf. Indeed, in this scenario traditional navigation devices such as GPS, compasses and gyrocompasses are unavailable or unreliable. In addition, the shape and thickness of the ice shelf is variable throughout the year. Current Arctic underwater navigation systems include sonar arrays to detect the proximity to the ice. However, these systems are undesirable in a wartime environment, as the sound gives away the position of the underwater vehicle. In this paper we briefly describe the theoretical design of a quantum imaging system that could allow the safe and stealthy navigation of underwater Arctic vehicles.
GPS surveying method applied to terminal area navigation flight experiments
Energy Technology Data Exchange (ETDEWEB)
Murata, M; Shingu, H; Satsushima, K; Tsuji, T; Ishikawa, K; Miyazawa, Y; Uchida, T [National Aerospace Laboratory, Tokyo (Japan)
1993-03-01
With an objective of evaluating accuracy of new landing and navigation systems such as microwave landing guidance system and global positioning satellite (GPS) system, flight experiments are being carried out using experimental aircraft. This aircraft mounts a GPS and evaluates its accuracy by comparing the standard orbits spotted by a Kalman filter from the laser tracing data on the aircraft with the navigation results. The GPS outputs position and speed information from an earth-centered-earth-fixed system called the World Geodetic System, 1984 (WGS84). However, in order to compare the navigation results with output from a reference orbit sensor or other navigation sensor, it is necessary to structure a high-precision reference coordinates system based on the WGS84. A method that applies the GPS phase interference measurement for this problem was proposed, and used actually in analyzing a flight experiment data. As referred to a case of the method having been applied to evaluating an independent navigation accuracy, the method was verified sufficiently effective and reliable not only in navigation method analysis, but also in the aspect of navigational operations. 12 refs., 10 figs., 5 tabs.
Compact autonomous navigation system (CANS)
Hao, Y. C.; Ying, L.; Xiong, K.; Cheng, H. Y.; Qiao, G. D.
2017-11-01
Autonomous navigation of Satellite and constellation has series of benefits, such as to reduce operation cost and ground station workload, to avoid the event of crises of war and natural disaster, to increase spacecraft autonomy, and so on. Autonomous navigation satellite is independent of ground station support. Many systems are developed for autonomous navigation of satellite in the past 20 years. Along them American MANS (Microcosm Autonomous Navigation System) [1] of Microcosm Inc. and ERADS [2] [3] (Earth Reference Attitude Determination System) of Honeywell Inc. are well known. The systems anticipate a series of good features of autonomous navigation and aim low cost, integrated structure, low power consumption and compact layout. The ERADS is an integrated small 3-axis attitude sensor system with low cost and small volume. It has the Earth center measurement accuracy higher than the common IR sensor because the detected ultraviolet radiation zone of the atmosphere has a brightness gradient larger than that of the IR zone. But the ERADS is still a complex system because it has to eliminate many problems such as making of the sapphire sphere lens, birefringence effect of sapphire, high precision image transfer optical fiber flattener, ultraviolet intensifier noise, and so on. The marginal sphere FOV of the sphere lens of the ERADS is used to star imaging that may be bring some disadvantages., i.e. , the image energy and attitude measurements accuracy may be reduced due to the tilt image acceptance end of the fiber flattener in the FOV. Besides Japan, Germany and Russia developed visible earth sensor for GEO [4] [5]. Do we have a way to develop a cheaper/easier and more accurate autonomous navigation system that can be used to all LEO spacecraft, especially, to LEO small and micro satellites? To return this problem we provide a new type of the system—CANS (Compact Autonomous Navigation System) [6].
Developments in Acoustic Navigation and Communication for High-Latitude Ocean Research
Gobat, J.; Lee, C.
2006-12-01
Developments in autonomous platforms (profiling floats, drifters, long-range gliders and propeller-driven vehicles) offer the possibility of unprecedented access to logistically difficult polar regions that challenge conventional techniques. Currently, however, navigation and telemetry for these platforms rely on satellite positioning and communications poorly suited for high-latitude applications where ice cover restricts access to the sea surface. A similar infrastructure offering basin-wide acoustic geolocation and telemetry would allow the community to employ autonomous platforms to address previously intractable problems in Arctic oceanography. Two recent efforts toward the development of such an infrastructure are reported here. As part of an observational array monitoring fluxes through Davis Strait, development of real-time RAFOS acoustic navigation for gliders has been ongoing since autumn 2004. To date, test deployments have been conducted in a 260 Hz field in the Pacific and 780 Hz fields off Norway and in Davis Strait. Real-time navigation accuracy of ~1~km is achievable. Autonomously navigating gliders will operate under ice cover beginning in autumn 2006. In addition to glider navigation development, the Davis Strait array moorings carry fixed RAFOS recorders to study propagation over a range of distances under seasonally varying ice cover. Results from the under-ice propagation and glider navigation experiments are presented. Motivated by the need to coordinate these types of development efforts, an international group of acousticians, autonomous platform developers, high-latitude oceanographers and marine mammal researchers gathered in Seattle, U.S.A. from 27 February -- 1 March 2006 for an NSF Office of Polar Programs sponsored Acoustic Navigation and Communication for High-latitude Ocean Research (ANCHOR) workshop. Workshop participants focused on summarizing the current state of knowledge concerning Arctic acoustics, navigation and communications
High-speed precision motion control
Yamaguchi, Takashi; Pang, Chee Khiang
2011-01-01
Written for researchers and postgraduate students in Control Engineering, as well as professionals in the Hard Disk Drive industry, this book discusses high-precision and fast servo controls in Hard Disk Drives (HDDs). The editors present a number of control algorithms that enable fast seeking and high precision positioning, and propose problems from commercial products, making the book valuable to researchers in HDDs. Each chapter is self contained, and progresses from concept to technique, present application examples that can be used within automotive, aerospace, aeronautical, and manufactu
High - speed steel for precise cased tools
International Nuclear Information System (INIS)
Karwiarz, J.; Mazur, A.
2001-01-01
The test results of high-vanadium high - speed steel (SWV9) for precise casted tools are presented. The face -milling cutters of NFCa80A type have been tested in industrial operating conditions. An average life - time of SWV9 steel tools was 3-10 times longer compare to the conventional high - speed milling cutters. Metallography of SWB9 precise casted steel revealed beneficial for tool properties distribution of primary vanadium carbides in the steel matrix. Presented results should be a good argument for wide application of high - vanadium high - speed steel for precise casted tools. (author)
Lu, Shan; Zhang, Hanmo
2016-01-01
To meet the requirement of autonomous orbit determination, this paper proposes a fast curve fitting method based on earth ultraviolet features to obtain accurate earth vector direction, in order to achieve the high precision autonomous navigation. Firstly, combining the stable characters of earth ultraviolet radiance and the use of transmission model software of atmospheric radiation, the paper simulates earth ultraviolet radiation model on different time and chooses the proper observation band. Then the fast improved edge extracting method combined Sobel operator and local binary pattern (LBP) is utilized, which can both eliminate noises efficiently and extract earth ultraviolet limb features accurately. And earth's centroid locations on simulated images are estimated via the least square fitting method using part of the limb edges. Taken advantage of the estimated earth vector direction and earth distance, Extended Kalman Filter (EKF) is applied to realize the autonomous navigation finally. Experiment results indicate the proposed method can achieve a sub-pixel earth centroid location estimation and extremely enhance autonomous celestial navigation precision.
Precision mechatronics based on high-precision measuring and positioning systems and machines
Jäger, Gerd; Manske, Eberhard; Hausotte, Tino; Mastylo, Rostyslav; Dorozhovets, Natalja; Hofmann, Norbert
2007-06-01
Precision mechatronics is defined in the paper as the science and engineering of a new generation of high precision systems and machines. Nanomeasuring and nanopositioning engineering represents important fields of precision mechatronics. The nanometrology is described as the today's limit of the precision engineering. The problem, how to design nanopositioning machines with uncertainties as small as possible will be discussed. The integration of several optical and tactile nanoprobes makes the 3D-nanopositioning machine suitable for various tasks, such as long range scanning probe microscopy, mask and wafer inspection, nanotribology, nanoindentation, free form surface measurement as well as measurement of microoptics, precision molds, microgears, ring gauges and small holes.
Majdani, Omid; Bartling, Soenke H; Leinung, Martin; Stöver, Timo; Lenarz, Minoo; Dullin, Christian; Lenarz, Thomas
2008-02-01
High-precision intraoperative navigation using high-resolution flat-panel volume computed tomography makes feasible the possibility of minimally invasive cochlear implant surgery, including cochleostomy. Conventional cochlear implant surgery is typically performed via mastoidectomy with facial recess to identify and avoid damage to vital anatomic landmarks. To accomplish this procedure via a minimally invasive approach--without performing mastoidectomy--in a precise fashion, image-guided technology is necessary. With such an approach, surgical time and expertise may be reduced, and hearing preservation may be improved. Flat-panel volume computed tomography was used to scan 4 human temporal bones. A drilling channel was planned preoperatively from the mastoid surface to the round window niche, providing a margin of safety to all functional important structures (e.g., facial nerve, chorda tympani, incus). Postoperatively, computed tomographic imaging and conventional surgical exploration of the drilled route to the cochlea were performed. All 4 specimens showed a cochleostomy located at the scala tympani anterior inferior to the round window. The chorda tympani was damaged in 1 specimen--this was preoperatively planned as a narrow facial recess was encountered. Using flat-panel volume computed tomography for image-guided surgical navigation, we were able to perform minimally invasive cochlear implant surgery defined as a narrow, single-channel mastoidotomy with cochleostomy. Although this finding is preliminary, it is technologically achievable.
High-Precision Computation and Mathematical Physics
International Nuclear Information System (INIS)
Bailey, David H.; Borwein, Jonathan M.
2008-01-01
At the present time, IEEE 64-bit floating-point arithmetic is sufficiently accurate for most scientific applications. However, for a rapidly growing body of important scientific computing applications, a higher level of numeric precision is required. Such calculations are facilitated by high-precision software packages that include high-level language translation modules to minimize the conversion effort. This paper presents a survey of recent applications of these techniques and provides some analysis of their numerical requirements. These applications include supernova simulations, climate modeling, planetary orbit calculations, Coulomb n-body atomic systems, scattering amplitudes of quarks, gluons and bosons, nonlinear oscillator theory, Ising theory, quantum field theory and experimental mathematics. We conclude that high-precision arithmetic facilities are now an indispensable component of a modern large-scale scientific computing environment.
Huang, Haoqian; Chen, Xiyuan; Zhang, Bo; Wang, Jian
2017-01-01
The underwater navigation system, mainly consisting of MEMS inertial sensors, is a key technology for the wide application of underwater gliders and plays an important role in achieving high accuracy navigation and positioning for a long time of period. However, the navigation errors will accumulate over time because of the inherent errors of inertial sensors, especially for MEMS grade IMU (Inertial Measurement Unit) generally used in gliders. The dead reckoning module is added to compensate the errors. In the complicated underwater environment, the performance of MEMS sensors is degraded sharply and the errors will become much larger. It is difficult to establish the accurate and fixed error model for the inertial sensor. Therefore, it is very hard to improve the accuracy of navigation information calculated by sensors. In order to solve the problem mentioned, the more suitable filter which integrates the multi-model method with an EKF approach can be designed according to different error models to give the optimal estimation for the state. The key parameters of error models can be used to determine the corresponding filter. The Adams explicit formula which has an advantage of high precision prediction is simultaneously fused into the above filter to achieve the much more improvement in attitudes estimation accuracy. The proposed algorithm has been proved through theory analyses and has been tested by both vehicle experiments and lake trials. Results show that the proposed method has better accuracy and effectiveness in terms of attitudes estimation compared with other methods mentioned in the paper for inertial navigation applied to underwater gliders. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.
Computer Navigation-aided Resection of Sacral Chordomas
Directory of Open Access Journals (Sweden)
Yong-Kun Yang
2016-01-01
Full Text Available Background: Resection of sacral chordomas is challenging. The anatomy is complex, and there are often no bony landmarks to guide the resection. Achieving adequate surgical margins is, therefore, difficult, and the recurrence rate is high. Use of computer navigation may allow optimal preoperative planning and improve precision in tumor resection. The purpose of this study was to evaluate the safety and feasibility of computer navigation-aided resection of sacral chordomas. Methods: Between 2007 and 2013, a total of 26 patients with sacral chordoma underwent computer navigation-aided surgery were included and followed for a minimum of 18 months. There were 21 primary cases and 5 recurrent cases, with a mean age of 55.8 years old (range: 35-84 years old. Tumors were located above the level of the S3 neural foramen in 23 patients and below the level of the S3 neural foramen in 3 patients. Three-dimensional images were reconstructed with a computed tomography-based navigation system combined with the magnetic resonance images using the navigation software. Tumors were resected via a posterior approach assisted by the computer navigation. Mean follow-up was 38.6 months (range: 18-84 months. Results: Mean operative time was 307 min. Mean intraoperative blood loss was 3065 ml. For computer navigation, the mean registration deviation during surgery was 1.7 mm. There were 18 wide resections, 4 marginal resections, and 4 intralesional resections. All patients were alive at the final follow-up, with 2 (7.7% exhibiting tumor recurrence. The other 24 patients were tumor-free. The mean Musculoskeletal Tumor Society Score was 27.3 (range: 19-30. Conclusions: Computer-assisted navigation can be safely applied to the resection of the sacral chordomas, allowing execution of preoperative plans, and achieving good oncological outcomes. Nevertheless, this needs to be accomplished by surgeons with adequate experience and skill.
Reliability of image-free navigation to monitor lower-limb alignment.
Pearle, Andrew D; Goleski, Patrick; Musahl, Volker; Kendoff, Daniel
2009-02-01
Proper alignment of the mechanical axis of the lower limb is the principal goal of a high tibial osteotomy. A well-accepted and relevant technical specification is the coronal plane lower-limb alignment. Target values for coronal plane alignment after high tibial osteotomy include 2 degrees of overcorrection, while tolerances for this specification have been established as 2 degrees to 4 degrees. However, the role of axial plane and sagittal plane realignment after high tibial osteotomy is poorly understood; consequently, targets and tolerance for this technical specification remain undefined. This article reviews the literature concerning the reliability and precision of navigation in monitoring the clinically relevant specification of lower-limb alignment in high tibial osteotomy. We conclude that image-free navigation registration may be clinically useful for intraoperative monitoring of the coronal plane only. Only fair and poor results for the axial and sagittal planes can be obtained by image-free navigation systems. In the future, combined image-based data, such as those from radiographs, magnetic resonance imaging, and gait analysis, may be used to help to improve the accuracy and reproducibility of quantitative intraoperative monitoring of lower-limb alignment.
Onboard Optical Navigation Measurement Processing in GEONS
National Aeronautics and Space Administration — Optical Navigation (OpNav) measurements derived from spacecraft-based images are a powerful data type in the precision orbit determination process. OpNav...
Directory of Open Access Journals (Sweden)
Zheping Yan
2018-03-01
Full Text Available To solve the navigation accuracy problems of multi-Unmanned Underwater Vehicles (multi-UUVs in the polar region, a polar cooperative navigation algorithm for multi-UUVs considering communication delays is proposed in this paper. UUVs are important pieces of equipment in ocean engineering for marine development. For UUVs to complete missions, precise navigation is necessary. It is difficult for UUVs to establish true headings because of the rapid convergence of Earth meridians and the severe polar environment. Based on the polar grid navigation algorithm, UUV navigation in the polar region can be accomplished with the Strapdown Inertial Navigation System (SINS in the grid frame. To save costs, a leader-follower type of system is introduced in this paper. The leader UUV helps the follower UUVs to achieve high navigation accuracy. Follower UUVs correct their own states based on the information sent by the leader UUV and the relative position measured by ultra-short baseline (USBL acoustic positioning. The underwater acoustic communication delay is quantized by the model. In this paper, considering underwater acoustic communication delay, the conventional adaptive Kalman filter (AKF is modified to adapt to polar cooperative navigation. The results demonstrate that the polar cooperative navigation algorithm for multi-UUVs that considers communication delays can effectively navigate the sailing of multi-UUVs in the polar region.
Park, Young W.; Montez, Moises N.
1994-01-01
A candidate onboard space navigation filter demonstrated excellent performance (less than 8 meter level RMS semi-major axis accuracy) in performing orbit determination of a low-Earth orbit Explorer satellite using single-frequency real GPS data. This performance is significantly better than predicted by other simulation studies using dual-frequency GPS data. The study results revealed the significance of two new modeling approaches evaluated in the work. One approach introduces a single-frequency ionospheric correction through pseudo-range and phase range averaging implementation. The other approach demonstrates a precise axis-dependent characterization of dynamic sample space uncertainty to compute a more accurate Kalman filter gain. Additionally, this navigation filter demonstrates a flexibility to accommodate both perturbational dynamic and observational biases required for multi-flight phase and inhomogeneous application environments. This paper reviews the potential application of these methods and the filter structure to terrestrial vehicle and positioning applications. Both the single-frequency ionospheric correction method and the axis-dependent state noise modeling approach offer valuable contributions in cost and accuracy improvements for terrestrial GPS receivers. With a modular design approach to either 'plug-in' or 'unplug' various force models, this multi-flight phase navigation filter design structure also provides a versatile GPS navigation software engine for both atmospheric and exo-atmospheric navigation or positioning use, thereby streamlining the flight phase or application-dependent software requirements. Thus, a standardized GPS navigation software engine that can reduce the development and maintenance cost of commercial GPS receivers is now possible.
Hou, Bowen; He, Zhangming; Li, Dong; Zhou, Haiyin; Wang, Jiongqi
2018-05-27
Strap-down inertial navigation system/celestial navigation system ( SINS/CNS) integrated navigation is a high precision navigation technique for ballistic missiles. The traditional navigation method has a divergence in the position error. A deeply integrated mode for SINS/CNS navigation system is proposed to improve the navigation accuracy of ballistic missile. The deeply integrated navigation principle is described and the observability of the navigation system is analyzed. The nonlinearity, as well as the large outliers and the Gaussian mixture noises, often exists during the actual navigation process, leading to the divergence phenomenon of the navigation filter. The new nonlinear Kalman filter on the basis of the maximum correntropy theory and unscented transformation, named the maximum correntropy unscented Kalman filter, is deduced, and the computational complexity is analyzed. The unscented transformation is used for restricting the nonlinearity of the system equation, and the maximum correntropy theory is used to deal with the non-Gaussian noises. Finally, numerical simulation illustrates the superiority of the proposed filter compared with the traditional unscented Kalman filter. The comparison results show that the large outliers and the influence of non-Gaussian noises for SINS/CNS deeply integrated navigation is significantly reduced through the proposed filter.
Towards high-speed autonomous navigation of unknown environments
Richter, Charles; Roy, Nicholas
2015-05-01
In this paper, we summarize recent research enabling high-speed navigation in unknown environments for dynamic robots that perceive the world through onboard sensors. Many existing solutions to this problem guarantee safety by making the conservative assumption that any unknown portion of the map may contain an obstacle, and therefore constrain planned motions to lie entirely within known free space. In this work, we observe that safety constraints may significantly limit performance and that faster navigation is possible if the planner reasons about collision with unobserved obstacles probabilistically. Our overall approach is to use machine learning to approximate the expected costs of collision using the current state of the map and the planned trajectory. Our contribution is to demonstrate fast but safe planning using a learned function to predict future collision probabilities.
Minster, J. H.; Altamimi, Z.; Blewitt, G.; Carter, W. E.; Cazenave, A. A.; Davis, J. L.; Dragert, H.; Feary, D. A.; Herring, T.; Larson, K. M.; Ries, J. C.; Sandwell, D. T.; Wahr, J. M.
2009-12-01
Over the past half-century, space geodetic technologies have changed profoundly the way we look at the planet, not only in the matter of details and accuracy, but also in the matter of how the entire planet changes with time, even on “human” time scales. The advent of space geodesy has provided exquisite images of the ever-changing land and ocean topography and global gravity field of the planet. We now enjoy an International Terrestrial Reference System with a time-dependent geocenter position accurate to a few millimeters. We can image small and large tectonic deformations of the surface before, during, and after earthquakes and volcanic eruptions. We measure both the past subtle changes as well as the recent dramatic changes in the ice sheets, and track global and regional sea-level change to a precision of a millimeter per year or better. The remarkable achievements of Earth observing missions over the past two decades, and the success of future international missions described in the Decadal Survey depend both implicitly and explicitly on the continued availability and enhancement of a reliable and resilient global infrastructure for precise geodesy, and on ongoing advances in geodetic science that are linked to it. This allows us to deal with global scientific, technological and social issues such as climate change and natural hazards, but the impact of the global precise geodetic infrastructure also permeates our everyday lives. Nowadays drivers, aviators, and sailors can determine their positions inexpensively to meter precision in real time, anywhere on the planet. In the foreseeable future, not only will we be able to know a vehicle’s position to centimeter accuracy in real time, but also to control that position, and thus introduce autonomous navigation systems for many tasks which are beyond the reach of “manual” navigation capabilities. This vision will only be realized with sustained international support of the precise global geodetic
Survey of computer vision technology for UVA navigation
Xie, Bo; Fan, Xiang; Li, Sijian
2017-11-01
Navigation based on computer version technology, which has the characteristics of strong independence, high precision and is not susceptible to electrical interference, has attracted more and more attention in the filed of UAV navigation research. Early navigation project based on computer version technology mainly applied to autonomous ground robot. In recent years, the visual navigation system is widely applied to unmanned machine, deep space detector and underwater robot. That further stimulate the research of integrated navigation algorithm based on computer version technology. In China, with many types of UAV development and two lunar exploration, the three phase of the project started, there has been significant progress in the study of visual navigation. The paper expounds the development of navigation based on computer version technology in the filed of UAV navigation research and draw a conclusion that visual navigation is mainly applied to three aspects as follows.(1) Acquisition of UAV navigation parameters. The parameters, including UAV attitude, position and velocity information could be got according to the relationship between the images from sensors and carrier's attitude, the relationship between instant matching images and the reference images and the relationship between carrier's velocity and characteristics of sequential images.(2) Autonomous obstacle avoidance. There are many ways to achieve obstacle avoidance in UAV navigation. The methods based on computer version technology ,including feature matching, template matching, image frames and so on, are mainly introduced. (3) The target tracking, positioning. Using the obtained images, UAV position is calculated by using optical flow method, MeanShift algorithm, CamShift algorithm, Kalman filtering and particle filter algotithm. The paper expounds three kinds of mainstream visual system. (1) High speed visual system. It uses parallel structure, with which image detection and processing are
Development and Flight Test of a Robust Optical-Inertial Navigation System Using Low-Cost Sensors
National Research Council Canada - National Science Library
Nielsen, Michael B
2008-01-01
.... This algorithm provides an alternative to the Global Positioning System (GPS) as a precision navigation source, enabling navigation in GPS denied environments, using low-cost sensors and equipment...
Comparative study of navigated versus freehand osteochondral graft transplantation of the knee.
Koulalis, Dimitrios; Di Benedetto, Paolo; Citak, Mustafa; O'Loughlin, Padhraig; Pearle, Andrew D; Kendoff, Daniel O
2009-04-01
Osteochondral lesions are a common sports-related injury for which osteochondral grafting, including mosaicplasty, is an established treatment. Computer navigation has been gaining popularity in orthopaedic surgery to improve accuracy and precision. Navigation improves angle and depth matching during harvest and placement of osteochondral grafts compared with conventional freehand open technique. Controlled laboratory study. Three cadaveric knees were used. Reference markers were attached to the femur, tibia, and donor/recipient site guides. Fifteen osteochondral grafts were harvested and inserted into recipient sites with computer navigation, and 15 similar grafts were inserted freehand. The angles of graft removal and placement as well as surface congruity (graft depth) were calculated for each surgical group. The mean harvesting angle at the donor site using navigation was 4 degrees (standard deviation, 2.3 degrees ; range, 1 degrees -9 degrees ) versus 12 degrees (standard deviation, 5.5 degrees ; range, 5 degrees -24 degrees ) using freehand technique (P standard deviation, 2.1 degrees ; range, 0 degrees -9 degrees ) versus 10.7 degrees (standard deviation, 4.9 degrees ; range, 2 degrees -17 degrees ) in freehand (P standard deviation, 2.0 degrees ; range, 1 degrees -9 degrees ) versus 10.6 degrees (standard deviation, 4.4 degrees ; range, 3 degrees -17 degrees ) with freehand technique (P = .0001). The mean height of plug protrusion under navigation was 0.3 mm (standard deviation, 0.2 mm; range, 0-0.6 mm) versus 0.5 mm (standard deviation, 0.3 mm; range, 0.2-1.1 mm) using a freehand technique (P = .0034). Significantly greater accuracy and precision were observed in harvesting and placement of the osteochondral grafts in the navigated procedures. Clinical studies are needed to establish a benefit in vivo. Improvement in the osteochondral harvest and placement is desirable to optimize clinical outcomes. Navigation shows great potential to improve both harvest
International Nuclear Information System (INIS)
Banovac, Filip; Tang, Jonathan; Xu Sheng; Lindisch, David; Chung, Ho Young; Levy, Elliot B.; Chang, Thomas; McCullough, Michael F.; Yaniv, Ziv; Wood, Bradford J.; Cleary, Kevin
2005-01-01
Radiofrequency ablation of primary and metastatic liver tumors is becoming a potential alternative to surgical resection. We propose a novel system that uses real-time electromagnetic position sensing of the needle tip to help with precision guidance into a liver tumor. The purpose of this study was to evaluate this technology in phantom and animal models. Using an electromagnetic navigation device, instrumented 18 g needles were advanced into radioopaque tumor targets in a respiratory liver phantom. The phantom featured a moving liver target that simulated cranio-caudal liver motion due to respiration. Skin-to-target path planning and real-time needle guidance were provided by a custom-designed software interface based on pre-operative 1 mm CT data slices. Needle probes were advanced using only the electromagnetic navigation device and software display. No conventional real-time imaging was used to assist in advancing the needle to the target. Two experienced operators (interventional radiologists) and two inexperienced ones (residents) used the system. The same protocol was then also used in two anesthetized 45 kg Yorkshire swine where radioopaque agar nodules were injected into the liver to serve as targets. A total of 76 tumor targeting attempts were performed in the liver phantom, and 32 attempts were done in the swine. The average time for path planning was 30 s in the phantom, and 63 s in the swine. The median time for the actual needle puncture to reach the desired target was 33 s in the phantom, and 42 s in the swine. The average registration error between the CT coordinate system and electromagnetic coordinate system was 1.4 mm (SD 0.3 mm) in the phantom, and 1.9 mm (SD 0.4 mm) in the swine. The median distance from the final needle tip position to the center of the tumor was 6.4 mm (SD 3.3 mm, n=76) in the phantom, and 8.3 mm (SD 3.7 mm, n=32) in the swine. There was no statistical difference in the planning time, procedure time, or accuracy of needle
Directory of Open Access Journals (Sweden)
Bowen Hou
2018-05-01
Full Text Available Strap-down inertial navigation system/celestial navigation system ( SINS/CNS integrated navigation is a high precision navigation technique for ballistic missiles. The traditional navigation method has a divergence in the position error. A deeply integrated mode for SINS/CNS navigation system is proposed to improve the navigation accuracy of ballistic missile. The deeply integrated navigation principle is described and the observability of the navigation system is analyzed. The nonlinearity, as well as the large outliers and the Gaussian mixture noises, often exists during the actual navigation process, leading to the divergence phenomenon of the navigation filter. The new nonlinear Kalman filter on the basis of the maximum correntropy theory and unscented transformation, named the maximum correntropy unscented Kalman filter, is deduced, and the computational complexity is analyzed. The unscented transformation is used for restricting the nonlinearity of the system equation, and the maximum correntropy theory is used to deal with the non-Gaussian noises. Finally, numerical simulation illustrates the superiority of the proposed filter compared with the traditional unscented Kalman filter. The comparison results show that the large outliers and the influence of non-Gaussian noises for SINS/CNS deeply integrated navigation is significantly reduced through the proposed filter.
DARPA looks beyond GPS for positioning, navigating, and timing
Energy Technology Data Exchange (ETDEWEB)
Kramer, David
2014-10-01
Cold-atom interferometry, microelectromechanical systems, signals of opportunity, and atomic clocks are some of the technologies the defense agency is pursuing to provide precise navigation when GPS is unavailable.
High-Precision Computation: Mathematical Physics and Dynamics
International Nuclear Information System (INIS)
Bailey, D.H.; Barrio, R.; Borwein, J.M.
2010-01-01
At the present time, IEEE 64-bit oating-point arithmetic is suficiently accurate for most scientic applications. However, for a rapidly growing body of important scientic computing applications, a higher level of numeric precision is required. Such calculations are facilitated by high-precision software packages that include high-level language translation modules to minimize the conversion e ort. This pa- per presents a survey of recent applications of these techniques and provides someanalysis of their numerical requirements. These applications include supernova simulations, climate modeling, planetary orbit calculations, Coulomb n-body atomic systems, studies of the one structure constant, scattering amplitudes of quarks, glu- ons and bosons, nonlinear oscillator theory, experimental mathematics, evaluation of orthogonal polynomials, numerical integration of ODEs, computation of periodic orbits, studies of the splitting of separatrices, detection of strange nonchaotic at- tractors, Ising theory, quantum held theory, and discrete dynamical systems. We conclude that high-precision arithmetic facilities are now an indispensable compo- nent of a modern large-scale scientic computing environment.
High-Precision Computation: Mathematical Physics and Dynamics
Energy Technology Data Exchange (ETDEWEB)
Bailey, D. H.; Barrio, R.; Borwein, J. M.
2010-04-01
At the present time, IEEE 64-bit oating-point arithmetic is suficiently accurate for most scientic applications. However, for a rapidly growing body of important scientic computing applications, a higher level of numeric precision is required. Such calculations are facilitated by high-precision software packages that include high-level language translation modules to minimize the conversion e ort. This pa- per presents a survey of recent applications of these techniques and provides someanalysis of their numerical requirements. These applications include supernova simulations, climate modeling, planetary orbit calculations, Coulomb n-body atomic systems, studies of the one structure constant, scattering amplitudes of quarks, glu- ons and bosons, nonlinear oscillator theory, experimental mathematics, evaluation of orthogonal polynomials, numerical integration of ODEs, computation of periodic orbits, studies of the splitting of separatrices, detection of strange nonchaotic at- tractors, Ising theory, quantum held theory, and discrete dynamical systems. We conclude that high-precision arithmetic facilities are now an indispensable compo- nent of a modern large-scale scientic computing environment.
High accuracy autonomous navigation using the global positioning system (GPS)
Truong, Son H.; Hart, Roger C.; Shoan, Wendy C.; Wood, Terri; Long, Anne C.; Oza, Dipak H.; Lee, Taesul
1997-01-01
The application of global positioning system (GPS) technology to the improvement of the accuracy and economy of spacecraft navigation, is reported. High-accuracy autonomous navigation algorithms are currently being qualified in conjunction with the GPS attitude determination flyer (GADFLY) experiment for the small satellite technology initiative Lewis spacecraft. Preflight performance assessments indicated that these algorithms are able to provide a real time total position accuracy of better than 10 m and a velocity accuracy of better than 0.01 m/s, with selective availability at typical levels. It is expected that the position accuracy will be increased to 2 m if corrections are provided by the GPS wide area augmentation system.
High precision target center determination from a point cloud
Directory of Open Access Journals (Sweden)
K. Kregar
2013-10-01
Full Text Available Many applications of terrestrial laser scanners (TLS require the determination of a specific point from a point cloud. In this paper procedure of high precision planar target center acquisition from point cloud is presented. The process is based on an image matching algorithm but before we can deal with raster image to fit a target on it, we need to properly determine the best fitting plane and project points on it. The main emphasis of this paper is in the precision estimation and propagation through the whole procedure which allows us to obtain precision assessment of final results (target center coordinates. Theoretic precision estimations – obtained through the procedure were rather high so we compared them with the empiric precision estimations obtained as standard deviations of results of 60 independently scanned targets. An χ2-test confirmed that theoretic precisions are overestimated. The problem most probably lies in the overestimated precisions of the plane parameters due to vast redundancy of points. However, empirical precisions also confirmed that the proposed procedure can ensure a submillimeter precision level. The algorithm can automatically detect grossly erroneous results to some extent. It can operate when the incidence angles of a laser beam are as high as 80°, which is desirable property if one is going to use planar targets as tie points in scan registration. The proposed algorithm will also contribute to improve TLS calibration procedures.
Li, Tianlong; Chang, Xiaocong; Wu, Zhiguang; Li, Jinxing; Shao, Guangbin; Deng, Xinghong; Qiu, Jianbin; Guo, Bin; Zhang, Guangyu; He, Qiang; Li, Longqiu; Wang, Joseph
2017-09-26
Self-propelled micro- and nanoscale robots represent a rapidly emerging and fascinating robotics research area. However, designing autonomous and adaptive control systems for operating micro/nanorobotics in complex and dynamically changing environments, which is a highly demanding feature, is still an unmet challenge. Here we describe a smart microvehicle for precise autonomous navigation in complicated environments and traffic scenarios. The fully autonomous navigation system of the smart microvehicle is composed of a microscope-coupled CCD camera, an artificial intelligence planner, and a magnetic field generator. The microscope-coupled CCD camera provides real-time localization of the chemically powered Janus microsphere vehicle and environmental detection for path planning to generate optimal collision-free routes, while the moving direction of the microrobot toward a reference position is determined by the external electromagnetic torque. Real-time object detection offers adaptive path planning in response to dynamically changing environments. We demonstrate that the autonomous navigation system can guide the vehicle movement in complex patterns, in the presence of dynamically changing obstacles, and in complex biological environments. Such a navigation system for micro/nanoscale vehicles, relying on vision-based close-loop control and path planning, is highly promising for their autonomous operation in complex dynamic settings and unpredictable scenarios expected in a variety of realistic nanoscale scenarios.
Current Role of Computer Navigation in Total Knee Arthroplasty.
Jones, Christopher W; Jerabek, Seth A
2018-01-31
Computer-assisted surgical (CAS) navigation has been developed with the aim of improving the accuracy and precision of total knee arthroplasty (TKA) component positioning and therefore overall limb alignment. The historical goal of knee arthroplasty has been to restore the mechanical alignment of the lower limb by aligning the femoral and tibial components perpendicular to the mechanical axis of the femur and tibia. Despite over 4 decades of TKA component development and nearly 2 decades of interest in CAS, the fundamental question remains; does the alignment goal and/or the method of achieving that goal affect the outcome of the TKA in terms of patient-reported outcome measures and/or overall survivorship? The quest for reliable and reproducible achievement of the intraoperative alignment goal has been the primary motivator for the introduction, development, and refinement of CAS navigation. Numerous proprietary systems now exist, and rapid technological advancements in computer processing power are stimulating further development of robotic surgical systems. Three categories of CAS can be defined: image-based large-console navigation; imageless large-console navigation, and more recently, accelerometer-based handheld navigation systems have been developed. A review of the current literature demonstrates that there are enough well-designed studies to conclude that both large-console CAS and handheld navigation systems improve the accuracy and precision of component alignment in TKA. However, missing from the evidence base, other than the subgroup analysis provided by the Australian Orthopaedic Association National Joint Replacement Registry, are any conclusive demonstrations of a clinical superiority in terms of improved patient-reported outcome measures and/or decreased cumulative revision rates in the long term. Few authors would argue that accuracy of alignment is a goal to ignore; therefore, in the absence of clinical evidence, many of the arguments against
Layered compression for high-precision depth data.
Miao, Dan; Fu, Jingjing; Lu, Yan; Li, Shipeng; Chen, Chang Wen
2015-12-01
With the development of depth data acquisition technologies, access to high-precision depth with more than 8-b depths has become much easier and determining how to efficiently represent and compress high-precision depth is essential for practical depth storage and transmission systems. In this paper, we propose a layered high-precision depth compression framework based on an 8-b image/video encoder to achieve efficient compression with low complexity. Within this framework, considering the characteristics of the high-precision depth, a depth map is partitioned into two layers: 1) the most significant bits (MSBs) layer and 2) the least significant bits (LSBs) layer. The MSBs layer provides rough depth value distribution, while the LSBs layer records the details of the depth value variation. For the MSBs layer, an error-controllable pixel domain encoding scheme is proposed to exploit the data correlation of the general depth information with sharp edges and to guarantee the data format of LSBs layer is 8 b after taking the quantization error from MSBs layer. For the LSBs layer, standard 8-b image/video codec is leveraged to perform the compression. The experimental results demonstrate that the proposed coding scheme can achieve real-time depth compression with satisfactory reconstruction quality. Moreover, the compressed depth data generated from this scheme can achieve better performance in view synthesis and gesture recognition applications compared with the conventional coding schemes because of the error control algorithm.
Pulsar Timing and Its Application for Navigation and Gravitational Wave Detection
Becker, Werner; Kramer, Michael; Sesana, Alberto
2018-02-01
Pulsars are natural cosmic clocks. On long timescales they rival the precision of terrestrial atomic clocks. Using a technique called pulsar timing, the exact measurement of pulse arrival times allows a number of applications, ranging from testing theories of gravity to detecting gravitational waves. Also an external reference system suitable for autonomous space navigation can be defined by pulsars, using them as natural navigation beacons, not unlike the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location (e.g. the solar system barycenter), the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. We describe the unique properties of pulsars that suggest that such a navigation system will certainly have its application in future astronautics. We also describe the on-going experiments to use the clock-like nature of pulsars to "construct" a galactic-sized gravitational wave detector for low-frequency (f_{GW}˜ 10^{-9} - 10^{-7} Hz) gravitational waves. We present the current status and provide an outlook for the future.
High-precision efficiency calibration of a high-purity co-axial germanium detector
Energy Technology Data Exchange (ETDEWEB)
Blank, B., E-mail: blank@cenbg.in2p3.fr [Centre d' Etudes Nucléaires de Bordeaux Gradignan, UMR 5797, CNRS/IN2P3, Université de Bordeaux, Chemin du Solarium, BP 120, 33175 Gradignan Cedex (France); Souin, J.; Ascher, P.; Audirac, L.; Canchel, G.; Gerbaux, M.; Grévy, S.; Giovinazzo, J.; Guérin, H.; Nieto, T. Kurtukian; Matea, I. [Centre d' Etudes Nucléaires de Bordeaux Gradignan, UMR 5797, CNRS/IN2P3, Université de Bordeaux, Chemin du Solarium, BP 120, 33175 Gradignan Cedex (France); Bouzomita, H.; Delahaye, P.; Grinyer, G.F.; Thomas, J.C. [Grand Accélérateur National d' Ions Lourds, CEA/DSM, CNRS/IN2P3, Bvd Henri Becquerel, BP 55027, F-14076 CAEN Cedex 5 (France)
2015-03-11
A high-purity co-axial germanium detector has been calibrated in efficiency to a precision of about 0.15% over a wide energy range. High-precision scans of the detector crystal and γ-ray source measurements have been compared to Monte-Carlo simulations to adjust the dimensions of a detector model. For this purpose, standard calibration sources and short-lived online sources have been used. The resulting efficiency calibration reaches the precision needed e.g. for branching ratio measurements of super-allowed β decays for tests of the weak-interaction standard model.
Weak gravitational lensing towards high-precision cosmology
International Nuclear Information System (INIS)
Berge, Joel
2007-01-01
This thesis aims at studying weak gravitational lensing as a tool for high-precision cosmology. We first present the development and validation of a precise and accurate tool for measuring gravitational shear, based on the shapelets formalism. We then use shapelets on real images for the first time, we analyze CFHTLS images, and combine them with XMM-LSS data. We measure the normalisation of the density fluctuations power spectrum σ 8 , and the one of the mass-temperature relation for galaxy clusters. The analysis of the Hubble space telescope COSMOS field confirms our σ 8 measurement and introduces tomography. Finally, aiming at optimizing future surveys, we compare the individual and combined merits of cluster counts and power spectrum tomography. Our results demonstrate that next generation surveys will allow weak lensing to yield its full potential in the high-precision cosmology era. (author) [fr
X-Ray Pulsar Based Navigation and Time Determination, Phase I
National Aeronautics and Space Administration — DARPA recently initiated the XNAV program to undertake development of GPS independent, precision navigation and time determination based on observations of certain...
Feasibility of remote magnetic navigation for epicardial ablation
P. Abraham; L.D. Abkenari; E.C.H. Peters; T. Szili-Torok (Tamas)
2013-01-01
textabstractPercutaneous epicardial mapping and ablation is an emerging method to treat ventricular tachycardias (VT), premature ventricular complexes (PVC), and accessory pathways. The use of a remote magnetic navigation system (MNS) could enhance precision and maintain safety. This multiple case
High precision detector robot arm system
Shu, Deming; Chu, Yong
2017-01-31
A method and high precision robot arm system are provided, for example, for X-ray nanodiffraction with an X-ray nanoprobe. The robot arm system includes duo-vertical-stages and a kinematic linkage system. A two-dimensional (2D) vertical plane ultra-precision robot arm supporting an X-ray detector provides positioning and manipulating of the X-ray detector. A vertical support for the 2D vertical plane robot arm includes spaced apart rails respectively engaging a first bearing structure and a second bearing structure carried by the 2D vertical plane robot arm.
Directory of Open Access Journals (Sweden)
V. V. Erokhin
2015-01-01
Full Text Available Algorithms of determination of coordinates of the aircraft in the integrated system of navigation and optimum control of a trajectory are considered. Results of researches of parameters of a navigation session and precision characteristics of an assessment of location showed that application of optimum control of a trajectory allowув to increase the accuracy of navigation definitions in case of incomplete constellation of navigation satellites.
Kinematic Navigation in Total Knee Replacement — Experience from the First 50 Cases
Directory of Open Access Journals (Sweden)
Chih-Wei Chang
2006-01-01
Conclusion: Use of a kinematic navigation system in TKR provides better accuracy than conventional manual methods. The technique is easy to use, has a short learning curve, and requires an additional operation time of less than 10 minutes. Precise alignment can be achieved with the aid of navigation in most cases.
Radio/FADS/IMU integrated navigation for Mars entry
Jiang, Xiuqiang; Li, Shuang; Huang, Xiangyu
2018-03-01
Supposing future orbiting and landing collaborative exploration mission as the potential project background, this paper addresses the issue of Mars entry integrated navigation using radio beacon, flush air data sensing system (FADS), and inertial measurement unit (IMU). The range and Doppler information sensed from an orbiting radio beacon, the dynamic pressure and heating data sensed from flush air data sensing system, and acceleration and attitude angular rate outputs from an inertial measurement unit are integrated in an unscented Kalman filter to perform state estimation and suppress the system and measurement noise. Computer simulations show that the proposed integrated navigation scheme can enhance the navigation accuracy, which enables precise entry guidance for the given Mars orbiting and landing collaborative exploration mission.
Radiation Tolerant Low Power Precision Time Source, Phase I
National Aeronautics and Space Administration — The availability of small, low power atomic clocks is now a reality for ground-based and airborne navigation systems. Kernco's Low Power Precision Time Source...
High-precision ground-based photometry of exoplanets
Directory of Open Access Journals (Sweden)
de Mooij Ernst J.W.
2013-04-01
Full Text Available High-precision photometry of transiting exoplanet systems has contributed significantly to our understanding of the properties of their atmospheres. The best targets are the bright exoplanet systems, for which the high number of photons allow very high signal-to-noise ratios. Most of the current instruments are not optimised for these high-precision measurements, either they have a large read-out overhead to reduce the readnoise and/or their field-of-view is limited, preventing simultaneous observations of both the target and a reference star. Recently we have proposed a new wide-field imager for the Observatoir de Mont-Megantic optimised for these bright systems (PI: Jayawardhana. The instruments has a dual beam design and a field-of-view of 17' by 17'. The cameras have a read-out time of 2 seconds, significantly reducing read-out overheads. Over the past years we have obtained significant experience with how to reach the high precision required for the characterisation of exoplanet atmospheres. Based on our experience we provide the following advice: Get the best calibrations possible. In the case of bad weather, characterise the instrument (e.g. non-linearity, dome flats, bias level, this is vital for better understanding of the science data. Observe the target for as long as possible, the out-of-transit baseline is as important as the transit/eclipse itself. A short baseline can lead to improperly corrected systematic and mis-estimation of the red-noise. Keep everything (e.g. position on detector, exposure time as stable as possible. Take care that the defocus is not too strong. For a large defocus, the contribution of the total flux from the sky-background in the aperture could well exceed that of the target, resulting in very strict requirements on the precision at which the background is measured.
High precision relative position sensing system for formation flying spacecraft
National Aeronautics and Space Administration — We propose to develop and test an optical sensing system that provides high precision relative position sensing for formation flying spacecraft. A high precision...
Flexible Particle Filter Navigation System for Analysis and Operations, Phase I
National Aeronautics and Space Administration — Odyssey Space Research proposes to develop a modular navigation software package to provide precise state information for offline analysis and real-time...
A Navigation/Positioning Service Based on Pseudolites Installed on Stratospheric Airships
辻井, 利昭; TSUJII, Toshiaki; 張替, 正敏; HARIGAE, Masatoshi
2002-01-01
Transmitters of GPS-like signals, called pseudolites (PL) or "pseudo-satellites" have been widely investigated as an additional ranging source for performance enhancement of GPS. Ground-based GPS augmentation systems using pseudolites have been investigated for several applications such as vehicle navigation in downtown urban canyons, positioning in deep open-cut pits and mines and precision landing of aircraft. The concept of an innovative GPS navigation/ positioning system augmented by airs...
High-precision performance testing of the LHC power converters
Bastos, M; Dreesen, P; Fernqvist, G; Fournier, O; Hudson, G
2007-01-01
The magnet power converters for LHC were procured in three parts, power part, current transducers and control electronics, to enable a maximum of industrial participation in the manufacturing and still guarantee the very high precision (a few parts in 10-6) required by LHC. One consequence of this approach was several stages of system tests: factory reception tests, CERN reception tests, integration tests , short-circuit tests and commissioning on the final load in the LHC tunnel. The majority of the power converters for LHC have now been delivered, integrated into complete converter and high-precision performance testing is well advanced. This paper presents the techniques used for high-precision testing and the results obtained.
Navigation and Control of a Vehicle to the Parking Place Using Ins
Directory of Open Access Journals (Sweden)
Rastislav PIRNÍK
2015-11-01
Full Text Available This article discusses possibility of usage of the inertial navigation system for an autonomous navigation of a vehicle to the parking place inside intelligent parking house. Our research has shown that inertial navigation is suitable only for heading and attitude estimation. In order to achieve reliable and precise position estimation the additional odometer sensor is required. Article also describes control algorithm which can be used for steering control of the car according to pre-set waypoints. Waypoints have to be placed with respect to the dimensions and overall maneuverability of the vehicle.
THE DEVELOPMENT OF NAVIGATION SYSTEMS IN CIVIL AVIATION
Directory of Open Access Journals (Sweden)
Anastasiya Sergeyevna Stepanenko
2017-01-01
Full Text Available The article describes the history of navigation systems formation, such as "Cicada" system, which at that time could compete with the US "Transit", European, Chinese Beidou navigation system and the Japanese Quasi-Zenit.The detailed information about improving the American GPS system, launched in 1978 and working till now is provided. The characteristics of GPS-III counterpart "Transit", which became the platform for creating such modern globalnavigation systems as GLONASS and GPS. The process of implementation of the GLONASS system in civil aviation, itssegments, functions and features are considered. The stages of GLONASS satellite system orbital grouping formation are analyzed. The author draws the analogy with the American GPS system, the GALILEO system, which has a number of additional advantages, are given. The author remarks the features of the European counterpart of the GALILEO global nav- igation system. One of the goals of this system is to provide a high-precision positioning system, which Europe can rely on regardless of the Russian GLONASS system, the US - GPS and the Chinese Beidou. GALILEO offers a unique global search and rescue function called SAR, with an important feedback function. The peculiarities of Chinese scientists’ navi- gation system, the Beidou satellite system, and the Japanese global Quasi-Zenith Satellite System are described.Global navigation systems development tendencies are considered. The author dwells upon the path to world satel- lite systems globalization, a good example of which is the trend towards GLONASS and Beidou unification. Most attention was paid to the latest development of Russian scientists’ autonomous navigation system SINS 2015, which is a strap-down inertial navigation system and allows you to navigate the aircraft without being connected to a global satellite system. The ways of navigation systems further development in Russia are determined. The two naturally opposite directions are
SEXTANT X-Ray Pulsar Navigation Demonstration: Flight System and Test Results
Winternitz, Luke; Mitchell, Jason W.; Hassouneh, Munther A.; Valdez, Jennifer E.; Price, Samuel R.; Semper, Sean R.; Yu, Wayne H.; Ray, Paul S.; Wood, Kent S.; Arzoumanian, Zaven;
2016-01-01
The Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) is a technology demonstration enhancement to the Neutron-star Interior Composition Explorer (NICER) mission. NICER is a NASA Explorer Mission of Opportunity that will be hosted on the International Space Station (ISS). SEXTANT will, for the first time, demonstrate real-time, on-board X-ray Pulsar Navigation (XNAV), a significant milestone in the quest to establish a GPS-like navigation capability available throughout our Solar System and beyond. This paper gives an overview of the SEXTANT system architecture and describes progress prior to environmental testing of the NICER flight instrument. It provides descriptions and development status of the SEXTANT flight software and ground system, as well as detailed description and results from the flight software functional and performance testing within the high-fidelity Goddard Space Flight Center (GSFC) X-ray Navigation Laboratory Testbed (GXLT) software and hardware simulation environment. Hardware-in-the-loop simulation results are presented, using the engineering model of the NICER timing electronics and the GXLT pulsar simulator-the GXLT precisely controls NASA GSFC's unique Modulated X-ray Source to produce X-rays that make the NICER detector electronics appear as if they were aboard the ISS viewing a sequence of millisecond pulsars
The study of high precision neutron moisture gauge
International Nuclear Information System (INIS)
Liu Shengkang; Bao Guanxiong; Sang Hai; Zhu Yuzhen
1993-01-01
The principle, structure and calibration experiment of the high precision neutron moisture gauge (insertion type) are described. The gauge has been appraised. The precision of the measuring moisture of coke is lower than 0.5%, and the range of the measuring moisture is 2%-12%. The economic benefit of the gauge application is good
A Bionic Polarization Navigation Sensor and Its Calibration Method.
Zhao, Huijie; Xu, Wujian
2016-08-03
The polarization patterns of skylight which arise due to the scattering of sunlight in the atmosphere can be used by many insects for deriving compass information. Inspired by insects' polarized light compass, scientists have developed a new kind of navigation method. One of the key techniques in this method is the polarimetric sensor which is used to acquire direction information from skylight. In this paper, a polarization navigation sensor is proposed which imitates the working principles of the polarization vision systems of insects. We introduce the optical design and mathematical model of the sensor. In addition, a calibration method based on variable substitution and non-linear curve fitting is proposed. The results obtained from the outdoor experiments provide support for the feasibility and precision of the sensor. The sensor's signal processing can be well described using our mathematical model. A relatively high degree of accuracy in polarization measurement can be obtained without any error compensation.
Quantum Entanglement and High Brightness Laser Source
National Aeronautics and Space Administration — Our focus is on demonstrating high precision (sub-micron) laser ranging for Navigation using a unique high-sensitivity optical correlation receiver with both...
A Microscopic Optically Tracking Navigation System That Uses High-resolution 3D Computer Graphics.
Yoshino, Masanori; Saito, Toki; Kin, Taichi; Nakagawa, Daichi; Nakatomi, Hirofumi; Oyama, Hiroshi; Saito, Nobuhito
2015-01-01
Three-dimensional (3D) computer graphics (CG) are useful for preoperative planning of neurosurgical operations. However, application of 3D CG to intraoperative navigation is not widespread because existing commercial operative navigation systems do not show 3D CG in sufficient detail. We have developed a microscopic optically tracking navigation system that uses high-resolution 3D CG. This article presents the technical details of our microscopic optically tracking navigation system. Our navigation system consists of three components: the operative microscope, registration, and the image display system. An optical tracker was attached to the microscope to monitor the position and attitude of the microscope in real time; point-pair registration was used to register the operation room coordinate system, and the image coordinate system; and the image display system showed the 3D CG image in the field-of-view of the microscope. Ten neurosurgeons (seven males, two females; mean age 32.9 years) participated in an experiment to assess the accuracy of this system using a phantom model. Accuracy of our system was compared with the commercial system. The 3D CG provided by the navigation system coincided well with the operative scene under the microscope. Target registration error for our system was 2.9 ± 1.9 mm. Our navigation system provides a clear image of the operation position and the surrounding structures. Systems like this may reduce intraoperative complications.
Directory of Open Access Journals (Sweden)
Wei Wei
2013-01-01
Full Text Available Since Wireless sensor networks (WSNs are dramatically being arranged in mission-critical applications,it changes into necessary that we consider application requirements in Internet of Things. We try to use WSNs to assist information query and navigation within a practical parking spaces environment. Integrated with high-performance OFDM by piece-wise polynomial approximation, we present a new method that is based on a diffusion equation and a position equation to accomplish the navigation process conveniently and efficiently. From the point of view of theoretical analysis, our jobs hold the lower constraint condition and several inappropriate navigation can be amended. Information diffusion and potential field are introduced to reach the goal of accurate navigation and gradient descent method is applied in the algorithm. Formula derivations and simulations manifest that the method facilitates the solution of typical sensor network configuration information navigation. Concurrently, we also treat channel estimation and ICI mitigation for very high mobility OFDM systems, and the communication is between a BS and mobile target at a terrible scenario. The scheme proposed here combines the piece-wise polynomial expansion to approximate timevariations of multipath channels. Two near symbols are applied to estimate the first-and second-order parameters. So as to improve the estimation accuracy and mitigate the ICI caused by pilot-aided estimation, the multipath channel parameters were reestimated in timedomain employing the decided OFDM symbol. Simulation results show that this method would improve system performance in a complex environment.
Demonstration of coherent Doppler lidar for navigation in GPS-denied environments
Amzajerdian, Farzin; Hines, Glenn D.; Pierrottet, Diego F.; Barnes, Bruce W.; Petway, Larry B.; Carson, John M.
2017-05-01
A coherent Doppler lidar has been developed to address NASA's need for a high-performance, compact, and cost-effective velocity and altitude sensor onboard its landing vehicles. Future robotic and manned missions to solar system bodies require precise ground-relative velocity vector and altitude data to execute complex descent maneuvers and safe, soft landing at a pre-designated site. This lidar sensor, referred to as a Navigation Doppler Lidar (NDL), meets the required performance of the landing missions while complying with vehicle size, mass, and power constraints. Operating from up to four kilometers altitude, the NDL obtains velocity and range precision measurements reaching 2 cm/sec and 2 meters, respectively, dominated by the vehicle motion. Terrestrial aerial vehicles will also benefit from NDL data products as enhancement or replacement to GPS systems when GPS is unavailable or redundancy is needed. The NDL offers a viable option to aircraft navigation in areas where the GPS signal can be blocked or jammed by intentional or unintentional interference. The NDL transmits three laser beams at different pointing angles toward the ground to measure range and velocity along each beam using a frequency modulated continuous wave (FMCW) technique. The three line-of-sight measurements are then combined in order to determine the three components of the vehicle velocity vector and its altitude relative to the ground. This paper describes the performance and capabilities that the NDL demonstrated through extensive ground tests, helicopter flight tests, and onboard an autonomous rocket-powered test vehicle while operating in closedloop with a guidance, navigation, and control (GN and C) system.
Navigation integrity monitoring and obstacle detection for enhanced-vision systems
Korn, Bernd; Doehler, Hans-Ullrich; Hecker, Peter
2001-08-01
Typically, Enhanced Vision (EV) systems consist of two main parts, sensor vision and synthetic vision. Synthetic vision usually generates a virtual out-the-window view using databases and accurate navigation data, e. g. provided by differential GPS (DGPS). The reliability of the synthetic vision highly depends on both, the accuracy of the used database and the integrity of the navigation data. But especially in GPS based systems, the integrity of the navigation can't be guaranteed. Furthermore, only objects that are stored in the database can be displayed to the pilot. Consequently, unexpected obstacles are invisible and this might cause severe problems. Therefore, additional information has to be extracted from sensor data to overcome these problems. In particular, the sensor data analysis has to identify obstacles and has to monitor the integrity of databases and navigation. Furthermore, if a lack of integrity arises, navigation data, e.g. the relative position of runway and aircraft, has to be extracted directly from the sensor data. The main contribution of this paper is about the realization of these three sensor data analysis tasks within our EV system, which uses the HiVision 35 GHz MMW radar of EADS, Ulm as the primary EV sensor. For the integrity monitoring, objects extracted from radar images are registered with both database objects and objects (e. g. other aircrafts) transmitted via data link. This results in a classification into known and unknown radar image objects and consequently, in a validation of the integrity of database and navigation. Furthermore, special runway structures are searched for in the radar image where they should appear. The outcome of this runway check contributes to the integrity analysis, too. Concurrent to this investigation a radar image based navigation is performed without using neither precision navigation nor detailed database information to determine the aircraft's position relative to the runway. The performance of our
Individual Global Navigation Satellite Systems in the Space Service Volume
Force, Dale A.
2015-01-01
Besides providing position, navigation, and timing (PNT) to terrestrial users, GPS is currently used to provide for precision orbit determination, precise time synchronization, real-time spacecraft navigation, and three-axis control of Earth orbiting satellites. With additional Global Navigation Satellite Systems (GNSS) coming into service (GLONASS, Beidou, and Galileo), it will be possible to provide these services by using other GNSS constellations. The paper, "GPS in the Space Service Volume," presented at the ION GNSS 19th International Technical Meeting in 2006 (Ref. 1), defined the Space Service Volume, and analyzed the performance of GPS out to 70,000 km. This paper will report a similar analysis of the performance of each of the additional GNSS and compare them with GPS alone. The Space Service Volume, defined as the volume between 3,000 km altitude and geosynchronous altitude, as compared with the Terrestrial Service Volume between the surface and 3,000 km. In the Terrestrial Service Volume, GNSS performance will be similar to performance on the Earth's surface. The GPS system has established signal requirements for the Space Service Volume. A separate paper presented at the conference covers the use of multiple GNSS in the Space Service Volume.
Low Cost Precision Lander for Lunar Exploration
Head, J. N.; Gardner, T. G.; Hoppa, G. V.; Seybold, K. G.
2004-12-01
For 60 years the US Defense Department has invested heavily in producing small, low mass, precision guided vehicles. The technologies matured under these programs include terrain-aided navigation, closed loop terminal guidance algorithms, robust autopilots, high thrust-to-weight propulsion, autonomous mission management software, sensors, and data fusion. These technologies will aid NASA in addressing New Millennium Science and Technology goals as well as the requirements flowing from the Vision articulated in January 2004. Establishing and resupplying a long term lunar presence will require automated landing precision not yet demonstrated. Precision landing will increase safety and assure mission success. In the DOD world, such technologies are used routinely and reliably. Hence, it is timely to generate a point design for a precise planetary lander useful for lunar exploration. In this design science instruments amount to 10 kg, 16% of the lander vehicle mass. This compares favorably with 7% for Mars Pathfinder and less than 15% for Surveyor. The mission design flies the lander in an inert configuration to the moon, relying on a cruise stage for navigation and TCMs. The lander activates about a minute before impact. A solid booster reduces the vehicle speed to 300-450 m/s. The lander is now about 2 minutes from touchdown and has 600 to 700 m/s delta-v capability, allowing for about 10 km of vehicle divert during terminal descent. This concept of operations is chosen because it closely mimics missile operational timelines used for decades: the vehicle remains inert in a challenging environment, then must execute its mission flawlessly on a moment's notice. The vehicle design consists of a re-plumbed propulsion system, using propellant tanks and thrusters from exoatmospheric programs. A redesigned truss provides hard points for landing gear, electronics, power supply, and science instruments. A radar altimeter and a Digital Scene Matching Area Correlator (DSMAC
An improved gravity compensation method for high-precision free-INS based on MEC–BP–AdaBoost
International Nuclear Information System (INIS)
Zhou, Xiao; Yang, Gongliu; Wang, Jing; Li, Jing
2016-01-01
In recent years, with the rapid improvement of inertial sensors (accelerometers and gyroscopes), gravity compensation has become more important for improving navigation accuracy in inertial navigation systems (INS), especially for high-precision INS. This paper proposes a mind evolutionary computation (MEC) back propagation (BP) AdaBoost algorithm neural-network-based gravity compensation method that estimates the gravity disturbance on the track based on measured gravity data. A MEC–BP–AdaBoost network-based gravity compensation algorithm used in the training process to establish the prediction model takes the carrier position (longitude and latitude) provided by INS as the input data and the gravity disturbance as the output data, and then compensates the obtained gravity disturbance into the INS’s error equations to restrain the position error propagation. The MEC–BP–AdaBoost algorithm can not only effectively avoid BP neural networks being trapped in local extrema, but also perfectly solve the nonlinearity between the input and output data that cannot be solved by traditional interpolation methods, such as least-square collocation (LSC) interpolation. The accuracy and feasibility of the proposed interpolation method are verified through numerical tests. A comparison of several other compensation methods applied in field experiments, including LSC interpolation and traditional BP interpolation, highlights the superior performance of the proposed method. The field experiment results show that the maximum value of the position error can reduce by 28% with the proposed gravity compensation method. (paper)
Canoe: An Autonomous Infrastructure-Free Indoor Navigation System
Directory of Open Access Journals (Sweden)
Kai Dong
2017-04-01
Full Text Available The development of the Internet of Things (IoT has accelerated research in indoor navigation systems, a majority of which rely on adequate wireless signals and sources. Nonetheless, deploying such a system requires periodic site-survey, which is time consuming and labor intensive. To address this issue, in this paper we present Canoe, an indoor navigation system that considers shopping mall scenarios. In our system, we do not assume any prior knowledge, such as floor-plan or the shop locations, access point placement or power settings, historical RSS measurements or fingerprints, etc. Instead, Canoe requires only that the shop owners collect and publish RSS values at the entrances of their shops and can direct a consumer to any of these shops by comparing the observed RSS values. The locations of the consumers and the shops are estimated using maximum likelihood estimation. In doing this, the direction of the target shop relative to the current orientation of the consumer can be precisely computed, such that the direction that a consumer should move can be determined. We have conducted extensive simulations using a real-world dataset. Our experiments in a real shopping mall demonstrate that if 50% of the shops publish their RSS values, Canoe can precisely navigate a consumer within 30 s, with an error rate below 9%.
High precision, rapid laser hole drilling
Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.
2013-04-02
A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.
Automatic titrator for high precision plutonium assay
International Nuclear Information System (INIS)
Jackson, D.D.; Hollen, R.M.
1986-01-01
Highly precise assay of plutonium metal is required for accountability measurements. We have developed an automatic titrator for this determination which eliminates analyst bias and requires much less analyst time. The analyst is only required to enter sample data and start the titration. The automated instrument titrates the sample, locates the end point, and outputs the results as a paper tape printout. Precision of the titration is less than 0.03% relative standard deviation for a single determination at the 250-mg plutonium level. The titration time is less than 5 min
High-precision multi-node clock network distribution.
Chen, Xing; Cui, Yifan; Lu, Xing; Ci, Cheng; Zhang, Xuesong; Liu, Bo; Wu, Hong; Tang, Tingsong; Shi, Kebin; Zhang, Zhigang
2017-10-01
A high precision multi-node clock network for multiple users was built following the precise frequency transmission and time synchronization of 120 km fiber. The network topology adopts a simple star-shaped network structure. The clock signal of a hydrogen maser (synchronized with UTC) was recovered from a 120 km telecommunication fiber link and then was distributed to 4 sub-stations. The fractional frequency instability of all substations is in the level of 10 -15 in a second and the clock offset instability is in sub-ps in root-mean-square average.
Development of Real-Time Precise Positioning Algorithm Using GPS L1 Carrier Phase Data
Directory of Open Access Journals (Sweden)
Jeong-Ho Joh
2002-12-01
Full Text Available We have developed Real-time Phase DAta Processor(RPDAP for GPS L1 carrier. And also, we tested the RPDAP's positioning accuracy compared with results of real time kinematic(RTK positioning. While quality of the conventional L1 RTK positioning highly depend on receiving condition, the RPDAP can gives more stable positioning result because of different set of common GPS satellites, which searched by elevation mask angle and signal strength. In this paper, we demonstrated characteristics of the RPDAP compared with the L1 RTK technique. And we discussed several improvement ways to apply the RPDAP to precise real-time positioning using low-cost GPS receiver. With correcting the discussed weak points in near future, the RPDAP will be used in the field of precise real-time application, such as precise car navigation and precise personal location services.
High precision locating control system based on VCM for Talbot lithography
Yao, Jingwei; Zhao, Lixin; Deng, Qian; Hu, Song
2016-10-01
Aiming at the high precision and efficiency requirements of Z-direction locating in Talbot lithography, a control system based on Voice Coil Motor (VCM) was designed. In this paper, we built a math model of VCM and its moving characteristic was analyzed. A double-closed loop control strategy including position loop and current loop were accomplished. The current loop was implemented by driver, in order to achieve the rapid follow of the system current. The position loop was completed by the digital signal processor (DSP) and the position feedback was achieved by high precision linear scales. Feed forward control and position feedback Proportion Integration Differentiation (PID) control were applied in order to compensate for dynamic lag and improve the response speed of the system. And the high precision and efficiency of the system were verified by simulation and experiments. The results demonstrated that the performance of Z-direction gantry was obviously improved, having high precision, quick responses, strong real-time and easily to expend for higher precision.
High current precision long pulse electron beam position monitor
Nelson, S D; Fessenden, T J; Holmes, C
2000-01-01
Precision high current long pulse electron beam position monitoring has typically experienced problems with high Q sensors, sensors damped to the point of lack of precision, or sensors that interact substantially with any beam halo thus obscuring the desired signal. As part of the effort to develop a multi-axis electron beam transport system using transverse electromagnetic stripline kicker technology, it is necessary to precisely determine the position and extent of long high energy beams for accurate beam position control (6 - 40 MeV, 1 - 4 kA, 2 μs beam pulse, sub millimeter beam position accuracy.) The kicker positioning system utilizes shot-to-shot adjustments for reduction of relatively slow (< 20 MHz) motion of the beam centroid. The electron beams passing through the diagnostic systems have the potential for large halo effects that tend to corrupt position measurements.
Classification of LIDAR Data for Generating a High-Precision Roadway Map
Jeong, J.; Lee, I.
2016-06-01
Generating of a highly precise map grows up with development of autonomous driving vehicles. The highly precise map includes a precision of centimetres level unlike an existing commercial map with the precision of meters level. It is important to understand road environments and make a decision for autonomous driving since a robust localization is one of the critical challenges for the autonomous driving car. The one of source data is from a Lidar because it provides highly dense point cloud data with three dimensional position, intensities and ranges from the sensor to target. In this paper, we focus on how to segment point cloud data from a Lidar on a vehicle and classify objects on the road for the highly precise map. In particular, we propose the combination with a feature descriptor and a classification algorithm in machine learning. Objects can be distinguish by geometrical features based on a surface normal of each point. To achieve correct classification using limited point cloud data sets, a Support Vector Machine algorithm in machine learning are used. Final step is to evaluate accuracies of obtained results by comparing them to reference data The results show sufficient accuracy and it will be utilized to generate a highly precise road map.
CLASSIFICATION OF LIDAR DATA FOR GENERATING A HIGH-PRECISION ROADWAY MAP
Directory of Open Access Journals (Sweden)
J. Jeong
2016-06-01
Full Text Available Generating of a highly precise map grows up with development of autonomous driving vehicles. The highly precise map includes a precision of centimetres level unlike an existing commercial map with the precision of meters level. It is important to understand road environments and make a decision for autonomous driving since a robust localization is one of the critical challenges for the autonomous driving car. The one of source data is from a Lidar because it provides highly dense point cloud data with three dimensional position, intensities and ranges from the sensor to target. In this paper, we focus on how to segment point cloud data from a Lidar on a vehicle and classify objects on the road for the highly precise map. In particular, we propose the combination with a feature descriptor and a classification algorithm in machine learning. Objects can be distinguish by geometrical features based on a surface normal of each point. To achieve correct classification using limited point cloud data sets, a Support Vector Machine algorithm in machine learning are used. Final step is to evaluate accuracies of obtained results by comparing them to reference data The results show sufficient accuracy and it will be utilized to generate a highly precise road map.
Directory of Open Access Journals (Sweden)
Tae-Suk Bae
2018-01-01
Full Text Available Recently, an accurate positioning has become the kernel of autonomous navigation with the rapid growth of drones including mapping purpose. The Network-based Real-time Kinematic (NRTK system was predominantly used for precision positioning in many fields such as surveying and agriculture, mostly in static mode or low-speed operation. The NRTK positioning, in general, shows much better performance with the fixed integer ambiguities. However, the success rate of the ambiguity resolution is highly dependent on the ionospheric condition and the surrounding environment of Global Navigation Satellite System (GNSS positioning, which particularly corresponds to the low-cost GNSS receivers. We analyzed the effects of the ionospheric conditions on the GNSS NRTK, as well as the possibility of applying the mobile NRTK to drone navigation for mapping. Two NRTK systems in operation were analyzed during a period of high ionospheric conditions, and the accuracy and the performance were compared for several operational cases. The test results show that a submeter accuracy is available even with float ambiguity under a favorable condition (i.e., visibility of the satellites as well as stable ionosphere. We still need to consider how to deal with ionospheric disturbances which may prevent NRTK positioning.
High-Precision Registration of Point Clouds Based on Sphere Feature Constraints
Directory of Open Access Journals (Sweden)
Junhui Huang
2016-12-01
Full Text Available Point cloud registration is a key process in multi-view 3D measurements. Its precision affects the measurement precision directly. However, in the case of the point clouds with non-overlapping areas or curvature invariant surface, it is difficult to achieve a high precision. A high precision registration method based on sphere feature constraint is presented to overcome the difficulty in the paper. Some known sphere features with constraints are used to construct virtual overlapping areas. The virtual overlapping areas provide more accurate corresponding point pairs and reduce the influence of noise. Then the transformation parameters between the registered point clouds are solved by an optimization method with weight function. In that case, the impact of large noise in point clouds can be reduced and a high precision registration is achieved. Simulation and experiments validate the proposed method.
Video-rate or high-precision: a flexible range imaging camera
Dorrington, Adrian A.; Cree, Michael J.; Carnegie, Dale A.; Payne, Andrew D.; Conroy, Richard M.; Godbaz, John P.; Jongenelen, Adrian P. P.
2008-02-01
A range imaging camera produces an output similar to a digital photograph, but every pixel in the image contains distance information as well as intensity. This is useful for measuring the shape, size and location of objects in a scene, hence is well suited to certain machine vision applications. Previously we demonstrated a heterodyne range imaging system operating in a relatively high resolution (512-by-512) pixels and high precision (0.4 mm best case) configuration, but with a slow measurement rate (one every 10 s). Although this high precision range imaging is useful for some applications, the low acquisition speed is limiting in many situations. The system's frame rate and length of acquisition is fully configurable in software, which means the measurement rate can be increased by compromising precision and image resolution. In this paper we demonstrate the flexibility of our range imaging system by showing examples of high precision ranging at slow acquisition speeds and video-rate ranging with reduced ranging precision and image resolution. We also show that the heterodyne approach and the use of more than four samples per beat cycle provides better linearity than the traditional homodyne quadrature detection approach. Finally, we comment on practical issues of frame rate and beat signal frequency selection.
Method of high precision interval measurement in pulse laser ranging system
Wang, Zhen; Lv, Xin-yuan; Mao, Jin-jin; Liu, Wei; Yang, Dong
2013-09-01
Laser ranging is suitable for laser system, for it has the advantage of high measuring precision, fast measuring speed,no cooperative targets and strong resistance to electromagnetic interference,the measuremen of laser ranging is the key paremeters affecting the performance of the whole system.The precision of the pulsed laser ranging system was decided by the precision of the time interval measurement, the principle structure of laser ranging system was introduced, and a method of high precision time interval measurement in pulse laser ranging system was established in this paper.Based on the analysis of the factors which affected the precision of range measure,the pulse rising edges discriminator was adopted to produce timing mark for the start-stop time discrimination,and the TDC-GP2 high precision interval measurement system based on TMS320F2812 DSP was designed to improve the measurement precision.Experimental results indicate that the time interval measurement method in this paper can obtain higher range accuracy. Compared with the traditional time interval measurement system,the method simplifies the system design and reduce the influence of bad weather conditions,furthermore,it satisfies the requirements of low costs and miniaturization.
CPM Signals for Satellite Navigation in the S and C Bands.
Xue, Rui; Sun, Yanbo; Zhao, Danfeng
2015-06-05
Frequency allocations in the L band suitable for global navigation satellite system (GNSS) services are getting crowded and system providers face an ever tougher job when they try to bring in new signals and services while maintaining radio frequency compatibility. With the successive opening of the S and C bands to GNSS service, the multi-band combined navigation is predicted to become a key technology for future high-precision positioning navigation systems, and a single modulation scheme satisfying the requirements in each band is a promising solution for reducing user terminal complexity. A universal modulation scheme based on the continuous phase modulation (CPM) family suitable for the above bands' demands is proposed. Moreover, this paper has put forward two specific CPM signals for the S and C bands, respectively. Then the proposed modulation schemes, together with existing candidates, are comprehensively evaluated. Simulation results show that the proposed CPM signals can not only satisfy the constraint condition of compatibility in different bands well and reduce user terminal complexity, but also provide superior performance in terms of tracking accuracy, multi-path mitigation and anti-jamming compared to other candidate modulation schemes.
Navigation in head and neck oncological surgery: an emerging concept.
Gangloff, P; Mastronicola, R; Cortese, S; Phulpin, B; Sergeant, C; Guillemin, F; Eluecque, H; Perrot, C; Dolivet, G
2011-01-01
Navigation surgery, initially applied in rhinology, neurosurgery and orthopaedic cases, has been developed over the last twenty years. Surgery based on computed tomography data has become increasingly important in the head and neck region. The technique for hardware fusion between RMI and computed tomography is also becoming more useful. We use such device since 2006 in head and neck carcinologic situation. Navigation allows control of the resection in order to avoid and protect the precise anatomical structures (vessels and nerves). It also guides biopsy and radiofrequency. Therefore, quality of life is much more increased and morbidity is decreased for these patients who undergo major and mutilating head and neck surgery. Here we report the results of 33 navigation procedures performed for 31 patients in our institution.
High Precision Edge Detection Algorithm for Mechanical Parts
Duan, Zhenyun; Wang, Ning; Fu, Jingshun; Zhao, Wenhui; Duan, Boqiang; Zhao, Jungui
2018-04-01
High precision and high efficiency measurement is becoming an imperative requirement for a lot of mechanical parts. So in this study, a subpixel-level edge detection algorithm based on the Gaussian integral model is proposed. For this purpose, the step edge normal section line Gaussian integral model of the backlight image is constructed, combined with the point spread function and the single step model. Then gray value of discrete points on the normal section line of pixel edge is calculated by surface interpolation, and the coordinate as well as gray information affected by noise is fitted in accordance with the Gaussian integral model. Therefore, a precise location of a subpixel edge was determined by searching the mean point. Finally, a gear tooth was measured by M&M3525 gear measurement center to verify the proposed algorithm. The theoretical analysis and experimental results show that the local edge fluctuation is reduced effectively by the proposed method in comparison with the existing subpixel edge detection algorithms. The subpixel edge location accuracy and computation speed are improved. And the maximum error of gear tooth profile total deviation is 1.9 μm compared with measurement result with gear measurement center. It indicates that the method has high reliability to meet the requirement of high precision measurement.
Fiber Scrambling for High Precision Spectrographs
Kaplan, Zachary; Spronck, J. F. P.; Fischer, D.
2011-05-01
The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler precision and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called "super-Earths” (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a precision of 10 cm/s. One of the largest factors limiting Doppler precision is variation in the Point Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980's to couple telescopes to high-precision spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber's ability to produce an output beam independent of input. Our research is focused on characterizing the scrambling properties of several types of fibers, including circular, square and octagonal fibers. By measuring the intensity distribution after the fiber as a function of input beam position, we can simulate guiding errors that occur at an observatory. Through this, we can determine which fibers produce the most uniform outputs for the severest guiding errors, improving the PSF and allowing sub-m/s precision. However, extensive testing of fibers of supposedly identical core diameter, length and shape from the same manufacturer has revealed the "personality” of individual fibers. Personality describes differing intensity patterns for supposedly duplicate fibers illuminated identically. Here, we present our results on scrambling characterization as a function of fiber type, while studying individual fiber personality.
Estimating Zenith Tropospheric Delays from BeiDou Navigation Satellite System Observations
Directory of Open Access Journals (Sweden)
Xin Sui
2013-04-01
Full Text Available The GNSS derived Zenith Tropospheric Delay (ZTD plays today a very critical role in meteorological study and weather forecasts, as ZTDs of thousands of GNSS stations are operationally assimilated into numerical weather prediction models. Recently, the Chinese BeiDou Navigation Satellite System (BDS was officially announced to provide operational services around China and its neighborhood and it was demonstrated to be very promising for precise navigation and positioning. In this contribution, we concentrate on estimating ZTD using BDS observations to assess its capacity for troposphere remote sensing. A local network which is about 250 km from Beijing and comprised of six stations equipped with GPS- and BDS-capable receivers is utilized. Data from 5 to 8 November 2012 collected on the network is processed in network mode using precise orbits and in Precise Point Positioning mode using precise orbits and clocks. The precise orbits and clocks are generated from a tracking network with most of the stations in China and several stations around the world. The derived ZTDs are compared with that estimated from GPS data using the final products of the International GNSS Service (IGS. The comparison shows that the bias and the standard deviation of the ZTD differences are about 2 mm and 5 mm, respectively, which are very close to the differences of GPS ZTD estimated using different software packages.
High-precision thermal and electrical characterization of thermoelectric modules
Kolodner, Paul
2014-05-01
This paper describes an apparatus for performing high-precision electrical and thermal characterization of thermoelectric modules (TEMs). The apparatus is calibrated for operation between 20 °C and 80 °C and is normally used for measurements of heat currents in the range 0-10 W. Precision thermometry based on miniature thermistor probes enables an absolute temperature accuracy of better than 0.010 °C. The use of vacuum isolation, thermal guarding, and radiation shielding, augmented by a careful accounting of stray heat leaks and uncertainties, allows the heat current through the TEM under test to be determined with a precision of a few mW. The fractional precision of all measured parameters is approximately 0.1%.
How Does My Cellphone GPS Work?-The Physics of Precision Time-Keeping
Chu, Steven
The most precise measurements in all of science are frequency and frequency difference measurements, or alternatively, phase and phase change of electromagnetic waves. Improvements in time-keeping have opened up many horizons in fundamental and applied physics that range from the detection of gravity waves to the melting of glaciers and the depletion of underground aquifers. Precision time keeping has also had important practical applications such as in the navigation, beginning with the determination of the longitude position of sailing ships. We now use our cell phones to help us navigate city streets and hail taxis from Uber and Lyft based on our geographical position within a few meters. How did this come about? What will the new time-keeping technologies enable in the future?
High Precision Edge Detection Algorithm for Mechanical Parts
Directory of Open Access Journals (Sweden)
Duan Zhenyun
2018-04-01
Full Text Available High precision and high efficiency measurement is becoming an imperative requirement for a lot of mechanical parts. So in this study, a subpixel-level edge detection algorithm based on the Gaussian integral model is proposed. For this purpose, the step edge normal section line Gaussian integral model of the backlight image is constructed, combined with the point spread function and the single step model. Then gray value of discrete points on the normal section line of pixel edge is calculated by surface interpolation, and the coordinate as well as gray information affected by noise is fitted in accordance with the Gaussian integral model. Therefore, a precise location of a subpixel edge was determined by searching the mean point. Finally, a gear tooth was measured by M&M3525 gear measurement center to verify the proposed algorithm. The theoretical analysis and experimental results show that the local edge fluctuation is reduced effectively by the proposed method in comparison with the existing subpixel edge detection algorithms. The subpixel edge location accuracy and computation speed are improved. And the maximum error of gear tooth profile total deviation is 1.9 μm compared with measurement result with gear measurement center. It indicates that the method has high reliability to meet the requirement of high precision measurement.
Design and algorithm research of high precision airborne infrared touch screen
Zhang, Xiao-Bing; Wang, Shuang-Jie; Fu, Yan; Chen, Zhao-Quan
2016-10-01
There are shortcomings of low precision, touch shaking, and sharp decrease of touch precision when emitting and receiving tubes are failure in the infrared touch screen. A high precision positioning algorithm based on extended axis is proposed to solve these problems. First, the unimpeded state of the beam between emitting and receiving tubes is recorded as 0, while the impeded state is recorded as 1. Then, the method of oblique scan is used, in which the light of one emitting tube is used for five receiving tubes. The impeded information of all emitting and receiving tubes is collected as matrix. Finally, according to the method of arithmetic average, the position of the touch object is calculated. The extended axis positioning algorithm is characteristic of high precision in case of failure of individual infrared tube and affects slightly the precision. The experimental result shows that the 90% display area of the touch error is less than 0.25D, where D is the distance between adjacent emitting tubes. The conclusion is gained that the algorithm based on extended axis has advantages of high precision, little impact when individual infrared tube is failure, and using easily.
Using wide area differential GPS to improve total system error for precision flight operations
Alter, Keith Warren
Total System Error (TSE) refers to an aircraft's total deviation from the desired flight path. TSE can be divided into Navigational System Error (NSE), the error attributable to the aircraft's navigation system, and Flight Technical Error (FTE), the error attributable to pilot or autopilot control. Improvement in either NSE or FTE reduces TSE and leads to the capability to fly more precise flight trajectories. The Federal Aviation Administration's Wide Area Augmentation System (WAAS) became operational for non-safety critical applications in 2000 and will become operational for safety critical applications in 2002. This navigation service will provide precise 3-D positioning (demonstrated to better than 5 meters horizontal and vertical accuracy) for civil aircraft in the United States. Perhaps more importantly, this navigation system, which provides continuous operation across large regions, enables new flight instrumentation concepts which allow pilots to fly aircraft significantly more precisely, both for straight and curved flight paths. This research investigates the capabilities of some of these new concepts, including the Highway-In-The Sky (HITS) display, which not only improves FTE but also reduces pilot workload when compared to conventional flight instrumentation. Augmentation to the HITS display, including perspective terrain and terrain alerting, improves pilot situational awareness. Flight test results from demonstrations in Juneau, AK, and Lake Tahoe, CA, provide evidence of the overall feasibility of integrated, low-cost flight navigation systems based on these concepts. These systems, requiring no more computational power than current-generation low-end desktop computers, have immediate applicability to general aviation flight from Cessnas to business jets and can support safer and ultimately more economical flight operations. Commercial airlines may also, over time, benefit from these new technologies.
Flight Test Result for the Ground-Based Radio Navigation System Sensor with an Unmanned Air Vehicle.
Jang, Jaegyu; Ahn, Woo-Guen; Seo, Seungwoo; Lee, Jang Yong; Park, Jun-Pyo
2015-11-11
The Ground-based Radio Navigation System (GRNS) is an alternative/backup navigation system based on time synchronized pseudolites. It has been studied for some years due to the potential vulnerability issue of satellite navigation systems (e.g., GPS or Galileo). In the framework of our study, a periodic pulsed sequence was used instead of the randomized pulse sequence recommended as the RTCM (radio technical commission for maritime services) SC (special committee)-104 pseudolite signal, as a randomized pulse sequence with a long dwell time is not suitable for applications requiring high dynamics. This paper introduces a mathematical model of the post-correlation output in a navigation sensor, showing that the aliasing caused by the additional frequency term of a periodic pulsed signal leads to a false lock (i.e., Doppler frequency bias) during the signal acquisition process or in the carrier tracking loop of the navigation sensor. We suggest algorithms to resolve the frequency false lock issue in this paper, relying on the use of a multi-correlator. A flight test with an unmanned helicopter was conducted to verify the implemented navigation sensor. The results of this analysis show that there were no false locks during the flight test and that outliers stem from bad dilution of precision (DOP) or fluctuations in the received signal quality.
High precision pulsar timing and spin frequency second derivatives
Liu, X. J.; Bassa, C. G.; Stappers, B. W.
2018-05-01
We investigate the impact of intrinsic, kinematic and gravitational effects on high precision pulsar timing. We present an analytical derivation and a numerical computation of the impact of these effects on the first and second derivative of the pulsar spin frequency. In addition, in the presence of white noise, we derive an expression to determine the expected measurement uncertainty of a second derivative of the spin frequency for a given timing precision, observing cadence and timing baseline and find that it strongly depends on the latter (∝t-7/2). We show that for pulsars with significant proper motion, the spin frequency second derivative is dominated by a term dependent on the radial velocity of the pulsar. Considering the data sets from three Pulsar Timing Arrays, we find that for PSR J0437-4715 a detectable spin frequency second derivative will be present if the absolute value of the radial velocity exceeds 33 km s-1. Similarly, at the current timing precision and cadence, continued timing observations of PSR J1909-3744 for about another eleven years, will allow the measurement of its frequency second derivative and determine the radial velocity with an accuracy better than 14 km s-1. With the ever increasing timing precision and observing baselines, the impact of the, largely unknown, radial velocities of pulsars on high precision pulsar timing can not be neglected.
High precision 3D coordinates location technology for pellet
International Nuclear Information System (INIS)
Fan Yong; Zhang Jiacheng; Zhou Jingbin; Tang Jun; Xiao Decheng; Wang Chuanke; Dong Jianjun
2010-01-01
In inertial confinement fusion (ICF) system, manual way has been used to collimate the pellet traditionally, which is time-consuming and low-level automated. A new method based on Binocular Vision is proposed, which can place the prospecting apparatus on the public diagnosis platform to reach relevant engineering target and uses the high precision two dimension calibration board. Iterative method is adopted to satisfy 0.1 pixel for corner extraction precision. Furthermore, SVD decomposition is used to remove the singularity corners and advanced Zhang's calibration method is applied to promote camera calibration precision. Experiments indicate that the RMS of three dimension coordinate measurement precision is 25 μm, and the max system RMS of distance measurement is better than 100 μm, satisfying the system index requirement. (authors)
Finding Home: Landmark Ambiguity in Human Navigation
Directory of Open Access Journals (Sweden)
Simon Jetzschke
2017-07-01
Full Text Available Memories of places often include landmark cues, i.e., information provided by the spatial arrangement of distinct objects with respect to the target location. To study how humans combine landmark information for navigation, we conducted two experiments: To this end, participants were either provided with auditory landmarks while walking in a large sports hall or with visual landmarks while walking on a virtual-reality treadmill setup. We found that participants cannot reliably locate their home position due to ambiguities in the spatial arrangement when only one or two uniform landmarks provide cues with respect to the target. With three visual landmarks that look alike, the task is solved without ambiguity, while audio landmarks need to play three unique sounds for a similar performance. This reduction in ambiguity through integration of landmark information from 1, 2, and 3 landmarks is well modeled using a probabilistic approach based on maximum likelihood estimation. Unlike any deterministic model of human navigation (based e.g., on distance or angle information, this probabilistic model predicted both the precision and accuracy of the human homing performance. To further examine how landmark cues are integrated we introduced systematic conflicts in the visual landmark configuration between training of the home position and tests of the homing performance. The participants integrated the spatial information from each landmark near-optimally to reduce spatial variability. When the conflict becomes big, this integration breaks down and precision is sacrificed for accuracy. That is, participants return again closer to the home position, because they start ignoring the deviant third landmark. Relying on two instead of three landmarks, however, goes along with responses that are scattered over a larger area, thus leading to higher variability. To model the breakdown of integration with increasing conflict, the probabilistic model based on a
Dornfeld, David
2008-01-01
Today there is a high demand for high-precision products. The manufacturing processes are now highly sophisticated and derive from a specialized genre called precision engineering. Precision Manufacturing provides an introduction to precision engineering and manufacturing with an emphasis on the design and performance of precision machines and machine tools, metrology, tooling elements, machine structures, sources of error, precision machining processes and precision process planning. As well as discussing the critical role precision machine design for manufacturing has had in technological developments over the last few hundred years. In addition, the influence of sustainable manufacturing requirements in precision processes is introduced. Drawing upon years of practical experience and using numerous examples and illustrative applications, David Dornfeld and Dae-Eun Lee cover precision manufacturing as it applies to: The importance of measurement and metrology in the context of Precision Manufacturing. Th...
High-precision reflectivity measurements: improvements in the calibration procedure
Jupe, Marco; Grossmann, Florian; Starke, Kai; Ristau, Detlev
2003-05-01
The development of high quality optical components is heavily depending on precise characterization procedures. The reflectance and transmittance of laser components are the most important parameters for advanced laser applications. In the industrial fabrication of optical coatings, quality management is generally insured by spectral photometric methods according to ISO/DIS 15386 on a medium level of accuracy. Especially for high reflecting mirrors, a severe discrepancy in the determination of the absolute reflectivity can be found for spectral photometric procedures. In the first part of the CHOCLAB project, a method for measuring reflectance and transmittance with an enhanced precision was developed, which is described in ISO/WD 13697. In the second part of the CHOCLAB project, the evaluation and optimization for the presented method is scheduled. Within this framework international Round-Robin experiment is currently in progress. During this Round-Robin experiment, distinct deviations could be observed between the results of high precision measurement facilities of different partners. Based on the extended experiments, the inhomogeneity of the sample reflectivity was identified as one important origin for the deviation. Consequently, this inhomogeneity is also influencing the calibration procedure. Therefore, a method was developed that allows the calibration of the chopper blade using always the same position on the reference mirror. During the investigations, the homogeneity of several samples was characterized by a surface mapping procedure for 1064 nm. The measurement facility was extended to the additional wavelength 532 nm and a similar set-up was assembled at 10.6 μm. The high precision reflectivity procedure at the mentioned wavelengths is demonstrated for exemplary measurements.
System and method for high precision isotope ratio destructive analysis
Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R
2013-07-02
A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).
Towards Safe Navigation by Formalizing Navigation Rules
Directory of Open Access Journals (Sweden)
Arne Kreutzmann
2013-06-01
Full Text Available One crucial aspect of safe navigation is to obey all navigation regulations applicable, in particular the collision regulations issued by the International Maritime Organization (IMO Colregs. Therefore, decision support systems for navigation need to respect Colregs and this feature should be verifiably correct. We tackle compliancy of navigation regulations from a perspective of software verification. One common approach is to use formal logic, but it requires to bridge a wide gap between navigation concepts and simple logic. We introduce a novel domain specification language based on a spatio-temporal logic that allows us to overcome this gap. We are able to capture complex navigation concepts in an easily comprehensible representation that can direcly be utilized by various bridge systems and that allows for software verification.
High-precision x-ray spectroscopy of highly charged ions with microcalorimeters
International Nuclear Information System (INIS)
Kraft-Bermuth, S; Andrianov, V; Bleile, A; Echler, A; Egelhof, P; Grabitz, P; Ilieva, S; Kiselev, O; Meier, J; Kilbourne, C; McCammon, D
2013-01-01
The precise determination of the energy of the Lyman α1 and α2 lines in hydrogen-like heavy ions provides a sensitive test of quantum electrodynamics in very strong Coulomb fields. To improve the experimental precision, the new detector concept of microcalorimeters is now exploited for such measurements. Such detectors consist of compensated-doped silicon thermistors and Pb or Sn absorbers to obtain high quantum efficiency in the energy range of 40–70 keV, where the Doppler-shifted Lyman lines are located. For the first time, a microcalorimeter was applied in an experiment to precisely determine the transition energy of the Lyman lines of lead ions at the experimental storage ring at GSI. The energy of the Ly α1 line E(Ly-α1, 207 Pb 81+ ) = (77937 ± 12 stat ± 25 syst ) eV agrees within error bars with theoretical predictions. To improve the experimental precision, a new detector array with more pixels and better energy resolution was equipped and successfully applied in an experiment to determine the Lyman-α lines of gold ions 197 Au 78+ . (paper)
Moafipoor, Shahram
Personal navigators (PN) have been studied for about a decade in different fields and applications, such as safety and rescue operations, security and emergency services, and police and military applications. The common goal of all these applications is to provide precise and reliable position, velocity, and heading information of each individual in various environments. In the PN system developed in this dissertation, the underlying assumption is that the system does not require pre-existing infrastructure to enable pedestrian navigation. To facilitate this capability, a multisensor system concept, based on the Global Positioning System (GPS), inertial navigation, barometer, magnetometer, and a human pedometry model has been developed. An important aspect of this design is to use the human body as navigation sensor to facilitate Dead Reckoning (DR) navigation in GPS-challenged environments. The system is designed predominantly for outdoor environments, where occasional loss of GPS lock may happen; however, testing and performance demonstration have been extended to indoor environments. DR navigation is based on a relative-measurement approach, with the key idea of integrating the incremental motion information in the form of step direction (SD) and step length (SL) over time. The foundation of the intelligent navigation system concept proposed here rests in exploiting the human locomotion pattern, as well as change of locomotion in varying environments. In this context, the term intelligent navigation represents the transition from the conventional point-to-point DR to dynamic navigation using the knowledge about the mechanism of the moving person. This approach increasingly relies on integrating knowledge-based systems (KBS) and artificial intelligence (AI) methodologies, including artificial neural networks (ANN) and fuzzy logic (FL). In addition, a general framework of the quality control for the real-time validation of the DR processing is proposed, based on a
Rigorous high-precision enclosures of fixed points and their invariant manifolds
Wittig, Alexander N.
The well established concept of Taylor Models is introduced, which offer highly accurate C0 enclosures of functional dependencies, combining high-order polynomial approximation of functions and rigorous estimates of the truncation error, performed using verified arithmetic. The focus of this work is on the application of Taylor Models in algorithms for strongly non-linear dynamical systems. A method is proposed to extend the existing implementation of Taylor Models in COSY INFINITY from double precision coefficients to arbitrary precision coefficients. Great care is taken to maintain the highest efficiency possible by adaptively adjusting the precision of higher order coefficients in the polynomial expansion. High precision operations are based on clever combinations of elementary floating point operations yielding exact values for round-off errors. An experimental high precision interval data type is developed and implemented. Algorithms for the verified computation of intrinsic functions based on the High Precision Interval datatype are developed and described in detail. The application of these operations in the implementation of High Precision Taylor Models is discussed. An application of Taylor Model methods to the verification of fixed points is presented by verifying the existence of a period 15 fixed point in a near standard Henon map. Verification is performed using different verified methods such as double precision Taylor Models, High Precision intervals and High Precision Taylor Models. Results and performance of each method are compared. An automated rigorous fixed point finder is implemented, allowing the fully automated search for all fixed points of a function within a given domain. It returns a list of verified enclosures of each fixed point, optionally verifying uniqueness within these enclosures. An application of the fixed point finder to the rigorous analysis of beam transfer maps in accelerator physics is presented. Previous work done by
Directory of Open Access Journals (Sweden)
Hyungjik Oh
2016-03-01
Full Text Available This study developed an approach for improving Carrier-phase Differential Global Positioning System (CDGPS based realtime satellite relative navigation by applying laser baseline measurement data. The robustness against the space operational environment was considered, and a Synthetic Wavelength Interferometer (SWI algorithm based on a femtosecond laser measurement model was developed. The phase differences between two laser wavelengths were combined to measure precise distance. Generated laser data were used to improve estimation accuracy for the float ambiguity of CDGPS data. Relative navigation simulations in real-time were performed using the extended Kalman filter algorithm. The GPS and laser-combined relative navigation accuracy was compared with GPS-only relative navigation solutions to determine the impact of laser data on relative navigation. In numerical simulations, the success rate of integer ambiguity resolution increased when laser data was added to GPS data. The relative navigational errors also improved five-fold and two-fold, relative to the GPS-only error, for 250 m and 5 km initial relative distances, respectively. The methodology developed in this study is suitable for application to future satellite formation-flying missions.
High precision capacitive beam phase probe for KHIMA project
Energy Technology Data Exchange (ETDEWEB)
Hwang, Ji-Gwang, E-mail: windy206@hanmail.net [Korea Institute of Radiological and Medical Sciences, 215–4, Gongneung-dong, Nowon-t, Seoul 139–706 (Korea, Republic of); Yang, Tae-Keun [Korea Institute of Radiological and Medical Sciences, 215–4, Gongneung-dong, Nowon-t, Seoul 139–706 (Korea, Republic of); Forck, Peter [GSI Helmholtz Centre for Ion Research, Darmstadt 64291, German (Germany)
2016-11-21
In the medium energy beam transport (MEBT) line of KHIMA project, a high precision beam phase probe monitor is required for a precise tuning of RF phase and amplitude of Radio Frequency Quadrupole (RFQ) accelerator and IH-DTL linac. It is also used for measuring a kinetic energy of ion beam by time-of-flight (TOF) method using two phase probes. The capacitive beam phase probe has been developed. The electromagnetic design of the high precision phase probe was performed to satisfy the phase resolution of 1° (@200 MHz). It was confirmed by the test result using a wire test bench. The measured phase accuracy of the fabricated phase probe is 1.19 ps. The pre-amplifier electronics with the 0.125 ∼ 1.61 GHz broad-band was designed and fabricated for amplifying the signal strength. The results of RF frequency and beam energy measurement using a proton beam from the cyclotron in KIRAMS is presented.
Strategy for Realizing High-Precision VUV Spectro-Polarimeter
Ishikawa, R.; Narukage, N.; Kubo, M.; Ishikawa, S.; Kano, R.; Tsuneta, S.
2014-12-01
Spectro-polarimetric observations in the vacuum ultraviolet (VUV) range are currently the only means to measure magnetic fields in the upper chromosphere and transition region of the solar atmosphere. The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) aims to measure linear polarization at the hydrogen Lyman- α line (121.6 nm). This measurement requires a polarization sensitivity better than 0.1 %, which is unprecedented in the VUV range. We here present a strategy with which to realize such high-precision spectro-polarimetry. This involves the optimization of instrument design, testing of optical components, extensive analyses of polarization errors, polarization calibration of the instrument, and calibration with onboard data. We expect that this strategy will aid the development of other advanced high-precision polarimeters in the UV as well as in other wavelength ranges.
Berger, Moritz; Kallus, Sebastian; Nova, Igor; Ristow, Oliver; Eisenmann, Urs; Dickhaus, Hartmut; Kuhle, Reinald; Hoffmann, Jürgen; Seeberger, Robin
2015-11-01
Intraoperative guidance using electromagnetic navigation is an upcoming method in maxillofacial surgery. However, due to their unwieldy structures, especially the line-of-sight problem, optical navigation devices are not used for daily orthognathic surgery. Therefore, orthognathic surgery was simulated on study phantom skulls, evaluating the accuracy and handling of a new electromagnetic tracking system. Le-Fort I osteotomies were performed on 10 plastic skulls. Orthognathic surgical planning was done in the conventional way using plaster models. Accuracy of the gold standard, splint-based model surgery versus an electromagnetic tracking system was evaluated by measuring the actual maxillary deviation using bimaxillary splints and preoperative and postoperative cone beam computer tomography imaging. The distance of five anatomical marker points were compared pre- and postoperatively. The electromagnetic tracking system was significantly more accurate in all measured parameters compared with the gold standard using bimaxillary splints (p orthognathic surgery to 0.3 mm on average. The data of this preliminary study shows a high level of accuracy in surgical orthognathic performance using electromagnetic navigation, and may offer greater precision than the conventional plaster model surgery with bimaxillary splints. This preliminary work shows great potential for the establishment of an intraoperative electromagnetic navigation system for maxillofacial surgery. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
4D Dynamic Required Navigation Performance Final Report
Finkelsztein, Daniel M.; Sturdy, James L.; Alaverdi, Omeed; Hochwarth, Joachim K.
2011-01-01
New advanced four dimensional trajectory (4DT) procedures under consideration for the Next Generation Air Transportation System (NextGen) require an aircraft to precisely navigate relative to a moving reference such as another aircraft. Examples are Self-Separation for enroute operations and Interval Management for in-trail and merging operations. The current construct of Required Navigation Performance (RNP), defined for fixed-reference-frame navigation, is not sufficiently specified to be applicable to defining performance levels of such air-to-air procedures. An extension of RNP to air-to-air navigation would enable these advanced procedures to be implemented with a specified level of performance. The objective of this research effort was to propose new 4D Dynamic RNP constructs that account for the dynamic spatial and temporal nature of Interval Management and Self-Separation, develop mathematical models of the Dynamic RNP constructs, "Required Self-Separation Performance" and "Required Interval Management Performance," and to analyze the performance characteristics of these air-to-air procedures using the newly developed models. This final report summarizes the activities led by Raytheon, in collaboration with GE Aviation and SAIC, and presents the results from this research effort to expand the RNP concept to a dynamic 4D frame of reference.
29TH Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting
National Research Council Canada - National Science Library
1998-01-01
...) Applications of PTTI technology to evolving military navigation and communication systems; geodesy; aviation; and pulsars; 4) Dissemination of precise time and frequency by means of GPS, geosynchronous communication satellites, and computer networks.
Computer-assisted navigational surgery enhances safety in dental implantology.
Ng, F C; Ho, K H; Wexler, A
2005-06-01
Dental implants are increasingly used to restore missing dentition. These titanium implants are surgically installed in the edentulous alveolar ridge and allowed to osteointegrate with the bone during the healing phase. After osseo-integration, the implant is loaded with a prosthesis to replace the missing tooth. Conventional implant treatment planning uses study models, wax-ups and panoramic x-rays to prefabricate surgical stent to guide the preparation of the implant site. The drilling into the alveolar ridge is invariably a "blind" procedure as the part of the drill in bone is not visible. Stereotactic systems were first introduced into neurosurgery in 1986. Since then, computer-assisted navigational technology has brought major advances to neuro-, midface and orthopaedic surgeries, and more recently, to implant placement. This paper illustrates the use of real-time computer-guided navigational technology in enhancing safety in implant surgical procedures. Real-time computer-guided navigational technology enhances accuracy and precision of the surgical procedure, minimises complications and facilitates surgery in challenging anatomical locations.
Precision ring rolling technique and application in high-performance bearing manufacturing
Directory of Open Access Journals (Sweden)
Hua Lin
2015-01-01
Full Text Available High-performance bearing has significant application in many important industry fields, like automobile, precision machine tool, wind power, etc. Precision ring rolling is an advanced rotary forming technique to manufacture high-performance seamless bearing ring thus can improve the working life of bearing. In this paper, three kinds of precision ring rolling techniques adapt to different dimensional ranges of bearings are introduced, which are cold ring rolling for small-scale bearing, hot radial ring rolling for medium-scale bearing and hot radial-axial ring rolling for large-scale bearing. The forming principles, technological features and forming equipments for three kinds of precision ring rolling techniques are summarized, the technological development and industrial application in China are introduced, and the main technological development trend is described.
Reliable Location-Based Services from Radio Navigation Systems
Directory of Open Access Journals (Sweden)
Per Enge
2010-12-01
Full Text Available Loran is a radio-based navigation system originally designed for naval applications. We show that Loran-C’s high-power and high repeatable accuracy are fantastic for security applications. First, we show how to derive a precise location tag—with a sensitivity of about 20 meters—that is difficult to project to an exact location. A device can use our location tag to block or allow certain actions, without knowing its precise location. To ensure that our tag is reproducible we make use of fuzzy extractors, a mechanism originally designed for biometric authentication. We build a fuzzy extractor specifically designed for radio-type errors and give experimental evidence to show its effectiveness. Second, we show that our location tag is difficult to predict from a distance. For example, an observer cannot predict the location tag inside a guarded data center from a few hundreds of meters away. As an application, consider a location-aware disk drive that will only work inside the data center. An attacker who steals the device and is capable of spoofing Loran-C signals, still cannot make the device work since he does not know what location tag to spoof. We provide experimental data supporting our unpredictability claim.
Evaluating the performance of a low-cost GPS in precision agriculture applications
DEFF Research Database (Denmark)
Jensen, Kjeld; Larsen, Morten; Simonsen, Tom
2012-01-01
Field Robots are often equipped with a Real Time Kinematic (RTK) GPS to obtain precise positioning. In many precision agriculture applications, however, the robot operates in semi-structured environments like orchards and row crops, where local sensors such as computer vision and laser range...... scanners can produce accurate positioning relative to the crops. GPS is then primarily needed for robust inter-row navigation. This work evaluates a new low-cost GPS. Static tests were used to test the absolute accuracy. To test the GPS in a precision agriculture environment it was installed on a robot...
High precision redundant robotic manipulator
International Nuclear Information System (INIS)
Young, K.K.D.
1998-01-01
A high precision redundant robotic manipulator for overcoming contents imposed by obstacles or imposed by a highly congested work space is disclosed. One embodiment of the manipulator has four degrees of freedom and another embodiment has seven degrees of freedom. Each of the embodiments utilize a first selective compliant assembly robot arm (SCARA) configuration to provide high stiffness in the vertical plane, a second SCARA configuration to provide high stiffness in the horizontal plane. The seven degree of freedom embodiment also utilizes kinematic redundancy to provide the capability of avoiding obstacles that lie between the base of the manipulator and the end effector or link of the manipulator. These additional three degrees of freedom are added at the wrist link of the manipulator to provide pitch, yaw and roll. The seven degrees of freedom embodiment uses one revolute point per degree of freedom. For each of the revolute joints, a harmonic gear coupled to an electric motor is introduced, and together with properly designed based servo controllers provide an end point repeatability of less than 10 microns. 3 figs
Precise orbit determination of Multi-GNSS constellation including GPS GLONASS BDS and GALIEO
Dai, Xiaolei
2014-05-01
In addition to the existing American global positioning system (GPS) and the Russian global navigation satellite system (GLONASS), the new generation of GNSS is emerging and developing, such as the Chinese BeiDou satellite navigation system (BDS) and the European GALILEO system. Multi-constellation is expected to contribute to more accurate and reliable positioning and navigation service. However, the application of multi-constellation challenges the traditional precise orbit determination (POD) strategy that was designed usually for single constellation. In this contribution, we exploit a more rigorous multi-constellation POD strategy for the ongoing IGS multi-GNSS experiment (MGEX) where the common parameters are identical for each system, and the frequency- and system-specified parameters are employed to account for the inter-frequency and inter-system biases. Since the authorized BDS attitude model is not yet released, different BDS attitude model are implemented and their impact on orbit accuracy are studied. The proposed POD strategy was implemented in the PANDA (Position and Navigation Data Analyst) software and can process observations from GPS, GLONASS, BDS and GALILEO together. The strategy is evaluated with the multi-constellation observations from about 90 MGEX stations and BDS observations from the BeiDou experimental tracking network (BETN) of Wuhan University (WHU). Of all the MGEX stations, 28 stations record BDS observation, and about 80 stations record GALILEO observations. All these data were processed together in our software, resulting in the multi-constellation POD solutions. We assessed the orbit accuracy for GPS and GLONASS by comparing our solutions with the IGS final orbit, and for BDS and GALILEO by overlapping our daily orbit solution. The stability of inter-frequency bias of GLONASS and inter-system biases w.r.t. GPS for GLONASS, BDS and GALILEO were investigated. At last, we carried out precise point positioning (PPP) using the multi
Open-Loop Performance of COBALT Precision Landing Payload on a Commercial Sub-Orbital Rocket
Restrepo, Carolina I.; Carson, John M., III; Amzajerdian, Farzin; Seubert, Carl R.; Lovelace, Ronney S.; McCarthy, Megan M.; Tse, Teming; Stelling, Richard; Collins, Steven M.
2018-01-01
An open-loop flight test campaign of the NASA COBALT (CoOperative Blending of Autonomous Landing Technologies) platform was conducted onboard the Masten Xodiac suborbital rocket testbed. The COBALT platform integrates NASA Guidance, Navigation and Control (GN&C) sensing technologies for autonomous, precise soft landing, including the Navigation Doppler Lidar (NDL) velocity and range sensor and the Lander Vision System (LVS) Terrain Relative Navigation (TRN) system. A specialized navigation filter running onboard COBALT fuses the NDL and LVS data in real time to produce a navigation solution that is independent of GPS and suitable for future, autonomous, planetary, landing systems. COBALT was a passive payload during the open loop tests. COBALT's sensors were actively taking data and processing it in real time, but the Xodiac rocket flew with its own GPS-navigation system as a risk reduction activity in the maturation of the technologies towards space flight. A future closed-loop test campaign is planned where the COBALT navigation solution will be used to fly its host vehicle.
International Nuclear Information System (INIS)
Yin Xuebing; Zhao Huijie; Zeng Junyu; Qu Yufu
2007-01-01
A new acoustic grating fringe projector (AGFP) was developed for high-speed and high-precision 3D measurement. A new acoustic grating fringe projection theory is also proposed to describe the optical system. The AGFP instrument can adjust the spatial phase and period of fringes with unprecedented speed and accuracy. Using rf power proportional-integral-derivative (PID) control and CCD synchronous control, we obtain fringes with fine sinusoidal characteristics and realize high-speed acquisition of image data. Using the device, we obtained a precise phase map for a 3D profile. In addition, the AGFP can work in running fringe mode, which could be applied in other measurement fields
Application of high precision temperature control technology in infrared testing
Cao, Haiyuan; Cheng, Yong; Zhu, Mengzhen; Chu, Hua; Li, Wei
2017-11-01
In allusion to the demand of infrared system test, the principle of Infrared target simulator and the function of the temperature control are presented. The key technology of High precision temperature control is discussed, which include temperature gathering, PID control and power drive. The design scheme of temperature gathering is put forward. In order to reduce the measure error, discontinuously current and four-wire connection for the platinum thermal resistance are adopted. A 24-bits AD chip is used to improve the acquisition precision. Fuzzy PID controller is designed because of the large time constant and continuous disturbance of the environment temperature, which result in little overshoot, rapid response, high steady-state accuracy. Double power operational amplifiers are used to drive the TEC. Experiments show that the key performances such as temperature control precision and response speed meet the requirements.
High precision electrostatic potential calculations for cylindrically symmetric lenses
International Nuclear Information System (INIS)
Edwards, David Jr.
2007-01-01
A method is developed for a potential calculation within cylindrically symmetric electrostatic lenses using mesh relaxation techniques, and it is capable of considerably higher accuracies than currently available. The method involves (i) creating very high order algorithms (orders of 6, 8, and 10) for determining the potentials at points in the net using surrounding point values, (ii) eliminating the effect of the large errors caused by singular points, and (iii) reducing gradients in the high gradient regions of the geometry, thereby allowing the algorithms used in these regions to achieve greater precisions--(ii) and (iii) achieved by the use of telescopic multiregions. In addition, an algorithm for points one unit from a metal surface is developed, allowing general mesh point algorithms to be used in these situations, thereby taking advantage of the enhanced precision of the latter. A maximum error function dependent on a sixth order gradient of the potential is defined. With this the single point algorithmic errors are able to be viewed over the entire net. Finally, it is demonstrated that by utilizing the above concepts and procedures, the potential of a point in a reasonably high gradient region of a test geometry can realize a precision of less than 10 -10
Chen, Xiao-lei; Xu, Bai-nan; Wang, Fei; Meng, Xiang-hui; Zhang, Jun; Jiang, Jin-li; Yu, Xin-guang; Zhou, Ding-biao
2011-08-01
To explore the clinical value of functional neuro-navigation and high-field-strength intraoperative magnetic resonance imaging (iMRI) for the resection of intracerebral gliomas involving eloquent language structures. From April 2009 to April 2010, 48 patients with intracerebral gliomas involving eloquent language structures, were operated with functional neuro-navigation and iMRI. Blood oxygen level dependent functional MRI (BOLD-fMRI) was used to depict both Broca and Wernicke cortex, while diffusion tensor imaging (DTI) based fiber tracking was used to delineate arcuate fasciculus. The reconstructed language structures were integrated into a navigation system, so that intra-operative microscopic-based functional neuro-navigation could be achieved. iMRI was used to update the images for both language structures and residual tumors. All patients were evaluated for language function pre-operatively and post-operatively upon short-term and long-term follow-up. In all patients, functional neuro-navigation and iMRI were successfully achieved. In 38 cases (79.2%), gross total resection was accomplished, while in the rest 10 cases (20.8%), subtotal resection was achieved. Only 1 case (2.1%) developed long-term (more than 3 months) new language function deficits at post-operative follow-up. No peri-operative mortality was recorded. With functional neuro-navigation and iMRI, the eloquent structures for language can be precisely located, while the resection size can be accurately evaluated intra-operatively. This technique is safe and helpful for preservation of language function.
High precision efficiency calibration of a HPGe detector
International Nuclear Information System (INIS)
Nica, N.; Hardy, J.C.; Iacob, V.E.; Helmer, R.G.
2003-01-01
Many experiments involving measurements of γ rays require a very precise efficiency calibration. Since γ-ray detection and identification also requires good energy resolution, the most commonly used detectors are of the coaxial HPGe type. We have calibrated our 70% HPGe to ∼ 0.2% precision, motivated by the measurement of precise branching ratios (BR) in superallowed 0 + → 0 + β decays. These BRs are essential ingredients in extracting ft-values needed to test the Standard Model via the unitarity of the Cabibbo-Kobayashi-Maskawa matrix, a test that it currently fails by more than two standard deviations. To achieve the required high precision in our efficiency calibration, we measured 17 radioactive sources at a source-detector distance of 15 cm. Some of these were commercial 'standard' sources but we achieved the highest relative precision with 'home-made' sources selected because they have simple decay schemes with negligible side feeding, thus providing exactly matched γ-ray intensities. These latter sources were produced by us at Texas A and M by n-activation or by nuclear reactions. Another critical source among the 17 was a 60 Co source produced by Physikalisch-Technische Bundesanstalt, Braunschweig, Germany: its absolute activity was quoted to better than 0.06%. We used it to establish our absolute efficiency, while all the other sources were used to determine relative efficiencies, extending our calibration over a large energy range (40-3500 keV). Efficiencies were also determined with Monte Carlo calculations performed with the CYLTRAN code. The physical parameters of the Ge crystal were independently determined and only two (unmeasurable) dead-layers were adjusted, within physically reasonable limits, to achieve precise absolute agreement with our measured efficiencies. The combination of measured efficiencies at more than 60 individual energies and Monte Carlo calculations to interpolate between them allows us to quote the efficiency of our
High-precision mass measurements for the rp-process at JYFLTRAP
Directory of Open Access Journals (Sweden)
Canete Laetitia
2017-01-01
Full Text Available The double Penning trap JYFLTRAP at the University of Jyväskylä has been successfully used to achieve high-precision mass measurements of nuclei involved in the rapid proton-capture (rp process. A precise mass measurement of 31Cl is essential to estimate the waiting point condition of 30S in the rp-process occurring in type I x-ray bursts (XRBs. The mass-excess of 31C1 measured at JYFLTRAP, -7034.7(3.4 keV, is 15 more precise than the value given in the Atomic Mass Evaluation 2012. The proton separation energy Sp determined from the new mass-excess value confirmed that 30S is a waiting point, with a lower-temperature limit of 0.44 GK. The mass of 52Co effects both 51Fe(p,γ52Co and 52Co(p,γ53Ni reactions. The mass-excess value measured, - 34 331.6(6.6 keV is 30 times more precise than the value given in AME2012. The Q values for the 51Fe(p,γ52Co and 52Co(p,γ53Ni reactions are now known with a high precision, 1418(11 keV and 2588(26 keV respectively. The results show that 52Co is more proton bound and 53Ni less proton bound than what was expected from the extrapolated value.
Thorium spectrophotometric analysis with high precision
International Nuclear Information System (INIS)
Palmieri, H.E.L.
1983-06-01
An accurate and precise determination of thorium is proposed. Precision of about 0,1% is required for the determination of macroquantities of thorium processed. After an extensive literature search concerning this subject, spectrophotometric titration has been chosen, using disodium ethylenediaminetetraacetate (EDTA) solution and alizarin S as indicator. In order to obtain such a precision, an amount of 0,025 M EDTA solution precisely measured has been added and the titration was completed with less than 5 ml of 0,0025 M EDTA solution. It is usual to locate the end-point graphically, by plotting added titrant versus absorbance. The non-linear minimum square fit, using the Fletcher e Powell's minimization process and a computer program. (author)
Laser-based Relative Navigation Using GPS Measurements for Spacecraft Formation Flying
Lee, Kwangwon; Oh, Hyungjik; Park, Han-Earl; Park, Sang-Young; Park, Chandeok
2015-12-01
This study presents a precise relative navigation algorithm using both laser and Global Positioning System (GPS) measurements in real time. The measurement model of the navigation algorithm between two spacecraft is comprised of relative distances measured by laser instruments and single differences of GPS pseudo-range measurements in spherical coordinates. Based on the measurement model, the Extended Kalman Filter (EKF) is applied to smooth the pseudo-range measurements and to obtain the relative navigation solution. While the navigation algorithm using only laser measurements might become inaccurate because of the limited accuracy of spacecraft attitude estimation when the distance between spacecraft is rather large, the proposed approach is able to provide an accurate solution even in such cases by employing the smoothed GPS pseudo-range measurements. Numerical simulations demonstrate that the errors of the proposed algorithm are reduced by more than about 12% compared to those of an algorithm using only laser measurements, as the accuracy of angular measurements is greater than 0.001° at relative distances greater than 30 km.
A simulation of driven reconnection by a high precision MHD code
International Nuclear Information System (INIS)
Kusano, Kanya; Ouchi, Yasuo; Hayashi, Takaya; Horiuchi, Ritoku; Watanabe, Kunihiko; Sato, Tetsuya.
1988-01-01
A high precision MHD code, which has the fourth-order accuracy for both the spatial and time steps, is developed, and is applied to the simulation studies of two dimensional driven reconnection. It is confirm that the numerical dissipation of this new scheme is much less than that of two-step Lax-Wendroff scheme. The effect of the plasma compressibility on the reconnection dynamics is investigated by means of this high precision code. (author)
Recent high precision surveys at PEP
International Nuclear Information System (INIS)
Sah, R.C.
1980-12-01
The task of surveying and aligning the components of PEP has provided an opportunity to develop new instruments and techniques for the purpose of high precision surveys. The new instruments are quick and easy to use, and they automatically encode survey data and read them into the memory of an on-line computer. When measurements of several beam elements have been taken, the on-line computer analyzes the measured data, compares them with desired parameters, and calculates the required adjustments to beam element support stands
Employing Tropospheric Numerical Weather Prediction Model for High-Precision GNSS Positioning
Alves, Daniele; Gouveia, Tayna; Abreu, Pedro; Magário, Jackes
2014-05-01
In the past few years is increasing the necessity of realizing high accuracy positioning. In this sense, the spatial technologies have being widely used. The GNSS (Global Navigation Satellite System) has revolutionized the geodetic positioning activities. Among the existent methods one can emphasize the Precise Point Positioning (PPP) and network-based positioning. But, to get high accuracy employing these methods, mainly in real time, is indispensable to realize the atmospheric modeling (ionosphere and troposphere) accordingly. Related to troposphere, there are the empirical models (for example Saastamoinen and Hopfield). But when highly accuracy results (error of few centimeters) are desired, maybe these models are not appropriated to the Brazilian reality. In order to minimize this limitation arises the NWP (Numerical Weather Prediction) models. In Brazil the CPTEC/INPE (Center for Weather Prediction and Climate Studies / Brazilian Institute for Spatial Researches) provides a regional NWP model, currently used to produce Zenithal Tropospheric Delay (ZTD) predictions (http://satelite.cptec.inpe.br/zenital/). The actual version, called eta15km model, has a spatial resolution of 15 km and temporal resolution of 3 hours. In this paper the main goal is to accomplish experiments and analysis concerning the use of troposphere NWP model (eta15km model) in PPP and network-based positioning. Concerning PPP it was used data from dozens of stations over the Brazilian territory, including Amazon forest. The results obtained with NWP model were compared with Hopfield one. NWP model presented the best results in all experiments. Related to network-based positioning it was used data from GNSS/SP Network in São Paulo State, Brazil. This network presents the best configuration in the country to realize this kind of positioning. Actually the network is composed by twenty stations (http://www.fct.unesp.br/#!/pesquisa/grupos-de-estudo-e-pesquisa/gege//gnss-sp-network2789/). The
Usability Testing of Two Ambulatory EHR Navigators.
Hultman, Gretchen; Marquard, Jenna; Arsoniadis, Elliot; Mink, Pamela; Rizvi, Rubina; Ramer, Tim; Khairat, Saif; Fickau, Keri; Melton, Genevieve B
2016-01-01
Despite widespread electronic health record (EHR) adoption, poor EHR system usability continues to be a significant barrier to effective system use for end users. One key to addressing usability problems is to employ user testing and user-centered design. To understand if redesigning an EHR-based navigation tool with clinician input improved user performance and satisfaction. A usability evaluation was conducted to compare two versions of a redesigned ambulatory navigator. Participants completed tasks for five patient cases using the navigators, while employing a think-aloud protocol. The tasks were based on Meaningful Use (MU) requirements. The version of navigator did not affect perceived workload, and time to complete tasks was longer in the redesigned navigator. A relatively small portion of navigator content was used to complete the MU-related tasks, though navigation patterns were highly variable across participants for both navigators. Preferences for EHR navigation structures appeared to be individualized. This study demonstrates the importance of EHR usability assessments to evaluate group and individual performance of different interfaces and preferences for each design.
Motion robust high resolution 3D free-breathing pulmonary MRI using dynamic 3D image self-navigator.
Jiang, Wenwen; Ong, Frank; Johnson, Kevin M; Nagle, Scott K; Hope, Thomas A; Lustig, Michael; Larson, Peder E Z
2018-06-01
To achieve motion robust high resolution 3D free-breathing pulmonary MRI utilizing a novel dynamic 3D image navigator derived directly from imaging data. Five-minute free-breathing scans were acquired with a 3D ultrashort echo time (UTE) sequence with 1.25 mm isotropic resolution. From this data, dynamic 3D self-navigating images were reconstructed under locally low rank (LLR) constraints and used for motion compensation with one of two methods: a soft-gating technique to penalize the respiratory motion induced data inconsistency, and a respiratory motion-resolved technique to provide images of all respiratory motion states. Respiratory motion estimation derived from the proposed dynamic 3D self-navigator of 7.5 mm isotropic reconstruction resolution and a temporal resolution of 300 ms was successful for estimating complex respiratory motion patterns. This estimation improved image quality compared to respiratory belt and DC-based navigators. Respiratory motion compensation with soft-gating and respiratory motion-resolved techniques provided good image quality from highly undersampled data in volunteers and clinical patients. An optimized 3D UTE sequence combined with the proposed reconstruction methods can provide high-resolution motion robust pulmonary MRI. Feasibility was shown in patients who had irregular breathing patterns in which our approach could depict clinically relevant pulmonary pathologies. Magn Reson Med 79:2954-2967, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.
Directory of Open Access Journals (Sweden)
CHEN Liang
2017-05-01
Full Text Available GNSS satellite-based differential augment system is based on real-time orbit and clock augment message. The multi-GNSS real-time precise clock error estimation model is studied, and then the parameters estimated in traditional un-difference model are optimized and a high-efficient real-time clock simplified model is proposed and realized. The real-time orbit data processing based on PANDA is also analyzed. The results indicate that the real-time orbit radial accuracy of GPS, BeiDou MEO and Galileo is 1~5 cm, and the radial accuracy of the BeiDou GEO/IGSO satellite is about 10 cm. It is found that the optimized real-time clock simplified model is more efficient in one epoch than un-difference model and can be applied to high-frequency (such as 1 Hz updating of real-time clock augment message. The results show that the real-time clock error obtained by this model is absolute value and there is no constant bias. Based on the real-time orbit, the GPS real-time clock precision of the simplified model is about 0.24 ns, BeiDou GEO is about 0.50 ns, IGSO/MEO is about 0.22 ns and Galileo is about 0.32 ns. Using the multi-GNSS real-time data stream in GFZ, a multi-GNSS real-time augment prototype system is built and the real-time augment message is being broadcasted on the Internet. The real-time PPP centimeter-level service and meter-level navigation service based on pseudorange are realized based on this prototype system.
Reference satellite selection method for GNSS high-precision relative positioning
Directory of Open Access Journals (Sweden)
Xiao Gao
2017-03-01
Full Text Available Selecting the optimal reference satellite is an important component of high-precision relative positioning because the reference satellite directly influences the strength of the normal equation. The reference satellite selection methods based on elevation and positional dilution of precision (PDOP value were compared. Results show that all the above methods cannot select the optimal reference satellite. We introduce condition number of the design matrix in the reference satellite selection method to improve structure of the normal equation, because condition number can indicate the ill condition of the normal equation. The experimental results show that the new method can improve positioning accuracy and reliability in precise relative positioning.
Fully autonomous navigation for the NASA cargo transfer vehicle
Wertz, James R.; Skulsky, E. David
1991-01-01
A great deal of attention has been paid to navigation during the close approach (less than or equal to 1 km) phase of spacecraft rendezvous. However, most spacecraft also require a navigation system which provides the necessary accuracy for placing both satellites within the range of the docking sensors. The Microcosm Autonomous Navigation System (MANS) is an on-board system which uses Earth-referenced attitude sensing hardware to provide precision orbit and attitude determination. The system is capable of functioning from LEO to GEO and beyond. Performance depends on the number of available sensors as well as mission geometry; however, extensive simulations have shown that MANS will provide 100 m to 400 m (3(sigma)) position accuracy and 0.03 to 0.07 deg (3(sigma)) attitude accuracy in low Earth orbit. The system is independent of any external source, including GPS. MANS is expected to have a significant impact on ground operations costs, mission definition and design, survivability, and the potential development of very low-cost, fully autonomous spacecraft.
TECHNICAL AND TECHNOLOGICAL ASPECTS IN PLANT PROTECTION IN THE PRECISION FARMING SYSTEM
Directory of Open Access Journals (Sweden)
Mladen Jurišić
2015-06-01
Full Text Available The basic premise of precision farming as a larger amount of information is its availability to the farmer in making decision. Direct comparison of perennial parameters obtained from the plot results in purposefully, argumentative and optimal use of resources for work (while keeping in mind the ecological impact. Today, the development of satellite navigation technology and monitoring of agricultural machinery, and reducing the cost of these devices again revived the question of the precision agriculture application. Advanced farmers in developed agricultural countries already regularly apply some of the technological possibilities of precision farming. Precision agriculture and plant protection allow the farmer realizing high incomes while keeping safe natural resources. Using modern GIS technology machines collect data directly from the plot using sensors and integrate themselves into the data processing system. Processed information is used by a farmer taking GreenStar system for the new planned operation and achieving significant time and money spare. Precision agriculture offers the possibility of optimal care of each plant, not just the average, or the entire field. Low risk investments are one of the main factors of choice precise plant protection. The use of pilotless aircrafts remote sensing allow fast and economical obtaining data and sufficient precision information. Using modern technology such as Variable Rate Application (applying a variable volume and GreenStar software package it is possible to regulate the amount of care and protection.
Zahabi, Maryam; Zhang, Wenjuan; Pankok, Carl; Lau, Mei Ying; Shirley, James; Kaber, David
2017-11-01
Many occupations require both physical exertion and cognitive task performance. Knowledge of any interaction between physical demands and modalities of cognitive task information presentation can provide a basis for optimising performance. This study examined the effect of physical exertion and modality of information presentation on pattern recognition and navigation-related information processing. Results indicated males of equivalent high fitness, between the ages of 18 and 34, rely more on visual cues vs auditory or haptic for pattern recognition when exertion level is high. We found that navigation response time was shorter under low and medium exertion levels as compared to high intensity. Navigation accuracy was lower under high level exertion compared to medium and low levels. In general, findings indicated that use of the haptic modality for cognitive task cueing decreased accuracy in pattern recognition responses. Practitioner Summary: An examination was conducted on the effect of physical exertion and information presentation modality in pattern recognition and navigation. In occupations requiring information presentation to workers, who are simultaneously performing a physical task, the visual modality appears most effective under high level exertion while haptic cueing degrades performance.
Li, Junye; Hu, Jinglei; Wang, Binyu; Sheng, Liang; Zhang, Xinming
2018-03-01
In order to investigate the effect of abrasive flow polishing surface variable diameter pipe parts, with high precision dispensing needles as the research object, the numerical simulation of the process of polishing high precision dispensing needle was carried out. Analysis of different volume fraction conditions, the distribution of the dynamic pressure and the turbulence viscosity of the abrasive flow field in the high precision dispensing needle, through comparative analysis, the effectiveness of the abrasive grain polishing high precision dispensing needle was studied, controlling the volume fraction of silicon carbide can change the viscosity characteristics of the abrasive flow during the polishing process, so that the polishing quality of the abrasive grains can be controlled.
Design of all-weather celestial navigation system
Sun, Hongchi; Mu, Rongjun; Du, Huajun; Wu, Peng
2018-03-01
In order to realize autonomous navigation in the atmosphere, an all-weather celestial navigation system is designed. The research of celestial navigation system include discrimination method of comentropy and the adaptive navigation algorithm based on the P value. The discrimination method of comentropy is studied to realize the independent switching of two celestial navigation modes, starlight and radio. Finally, an adaptive filtering algorithm based on P value is proposed, which can greatly improve the disturbance rejection capability of the system. The experimental results show that the accuracy of the three axis attitude is better than 10″, and it can work all weather. In perturbation environment, the position accuracy of the integrated navigation system can be increased 20% comparing with the traditional method. It basically meets the requirements of the all-weather celestial navigation system, and it has the ability of stability, reliability, high accuracy and strong anti-interference.
High-Precision Half-Life Measurement for the Superallowed β+ Emitter Alm26
Finlay, P.; Ettenauer, S.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Andreoiu, C.; Austin, R. A. E.; Bandyopadhyay, D.; Cross, D. S.; Demand, G.; Djongolov, M.; Garrett, P. E.; Green, K. L.; Grinyer, G. F.; Hackman, G.; Leach, K. G.; Pearson, C. J.; Phillips, A. A.; Sumithrarachchi, C. S.; Triambak, S.; Williams, S. J.
2011-01-01
A high-precision half-life measurement for the superallowed β+ emitter Alm26 was performed at the TRIUMF-ISAC radioactive ion beam facility yielding T1/2=6346.54±0.46stat±0.60systms, consistent with, but 2.5 times more precise than, the previous world average. The Alm26 half-life and ft value, 3037.53(61) s, are now the most precisely determined for any superallowed β decay. Combined with recent theoretical corrections for isospin-symmetry-breaking and radiative effects, the corrected Ft value for Alm26, 3073.0(12) s, sets a new benchmark for the high-precision superallowed Fermi β-decay studies used to test the conserved vector current hypothesis and determine the Vud element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix.
Evaluation of the Terminal Sequencing and Spacing System for Performance Based Navigation Arrivals
Thipphavong, Jane; Jung, Jaewoo; Swenson, Harry N.; Martin, Lynne; Lin, Melody; Nguyen, Jimmy
2013-01-01
NASA has developed the Terminal Sequencing and Spacing (TSS) system, a suite of advanced arrival management technologies combining timebased scheduling and controller precision spacing tools. TSS is a ground-based controller automation tool that facilitates sequencing and merging arrivals that have both current standard ATC routes and terminal Performance-Based Navigation (PBN) routes, especially during highly congested demand periods. In collaboration with the FAA and MITRE's Center for Advanced Aviation System Development (CAASD), TSS system performance was evaluated in human-in-the-loop (HITL) simulations with currently active controllers as participants. Traffic scenarios had mixed Area Navigation (RNAV) and Required Navigation Performance (RNP) equipage, where the more advanced RNP-equipped aircraft had preferential treatment with a shorter approach option. Simulation results indicate the TSS system achieved benefits by enabling PBN, while maintaining high throughput rates-10% above baseline demand levels. Flight path predictability improved, where path deviation was reduced by 2 NM on average and variance in the downwind leg length was 75% less. Arrivals flew more fuel-efficient descents for longer, spending an average of 39 seconds less in step-down level altitude segments. Self-reported controller workload was reduced, with statistically significant differences at the p less than 0.01 level. The RNP-equipped arrivals were also able to more frequently capitalize on the benefits of being "Best-Equipped, Best- Served" (BEBS), where less vectoring was needed and nearly all RNP approaches were conducted without interruption.
Beaudoin, Yanick; Desbiens, André; Gagnon, Eric; Landry, René
2018-01-01
The navigation system of a satellite launcher is of paramount importance. In order to correct the trajectory of the launcher, the position, velocity and attitude must be known with the best possible precision. In this paper, the observability of four navigation solutions is investigated. The first one is the INS/GPS couple. Then, attitude reference sensors, such as magnetometers, are added to the INS/GPS solution. The authors have already demonstrated that the reference trajectory could be used to improve the navigation performance. This approach is added to the two previously mentioned navigation systems. For each navigation solution, the observability is analyzed with different sensor error models. First, sensor biases are neglected. Then, sensor biases are modelled as random walks and as first order Markov processes. The observability is tested with the rank and condition number of the observability matrix, the time evolution of the covariance matrix and sensitivity to measurement outlier tests. The covariance matrix is exploited to evaluate the correlation between states in order to detect structural unobservability problems. Finally, when an unobservable subspace is detected, the result is verified with theoretical analysis of the navigation equations. The results show that evaluating only the observability of a model does not guarantee the ability of the aiding sensors to correct the INS estimates within the mission time. The analysis of the covariance matrix time evolution could be a powerful tool to detect this situation, however in some cases, the problem is only revealed with a sensitivity to measurement outlier test. None of the tested solutions provide GPS position bias observability. For the considered mission, the modelling of the sensor biases as random walks or Markov processes gives equivalent results. Relying on the reference trajectory can improve the precision of the roll estimates. But, in the context of a satellite launcher, the roll
Optimizing MR imaging-guided navigation for focused ultrasound interventions in the brain
Werner, B.; Martin, E.; Bauer, R.; O'Gorman, R.
2017-03-01
MR imaging during transcranial MR imaging-guided Focused Ultrasound surgery (tcMRIgFUS) is challenging due to the complex ultrasound transducer setup and the water bolus used for acoustic coupling. Achievable image quality in the tcMRIgFUS setup using the standard body coil is significantly inferior to current neuroradiologic standards. As a consequence, MR image guidance for precise navigation in functional neurosurgical interventions using tcMRIgFUS is basically limited to the acquisition of MR coordinates of salient landmarks such as the anterior and posterior commissure for aligning a stereotactic atlas. Here, we show how improved MR image quality provided by a custom built MR coil and optimized MR imaging sequences can support imaging-guided navigation for functional tcMRIgFUS neurosurgery by visualizing anatomical landmarks that can be integrated into the navigation process to accommodate for patient specific anatomy.
High-precision two-dimensional atom localization via quantum interference in a tripod-type system
International Nuclear Information System (INIS)
Wang, Zhiping; Yu, Benli
2014-01-01
A scheme is proposed for high-precision two-dimensional atom localization in a four-level tripod-type atomic system via measurement of the excited state population. It is found that because of the position-dependent atom–field interaction, the precision of 2D atom localization can be significantly improved by appropriately adjusting the system parameters. Our scheme may be helpful in laser cooling or atom nanolithography via high-precision and high-resolution atom localization. (letter)
Towards High Productivity in Precision Grinding
Directory of Open Access Journals (Sweden)
W. Brian Rowe
2018-04-01
Full Text Available Over the last century, substantial advances have been made, based on improved understanding of the requirements of grinding processes, machines, control systems, materials, abrasives, wheel preparation, coolants, lubricants, and coolant delivery. This paper reviews a selection of areas in which the application of scientific principles and engineering ingenuity has led to the development of new grinding processes, abrasives, tools, machines, and systems. Topics feature a selection of areas where relationships between scientific principles and new techniques are yielding improved productivity and better quality. These examples point towards further advances that can fruitfully be pursued. Applications in modern grinding technology range from high-precision kinematics for grinding very large lenses and reflectors through to medium size grinding machine processes and further down to grinding very small components used in micro electro-mechanical systems (MEMS devices. The importance of material issues is emphasized for the range of conventional engineering steels, through to aerospace materials, ceramics, and composites. It is suggested that future advances in productivity will include the wider application of artificial intelligence and robotics to improve precision, process efficiency, and features required to integrate grinding processes into wider manufacturing systems.
High precision ray tracing in cylindrically symmetric electrostatics
Energy Technology Data Exchange (ETDEWEB)
Edwards Jr, David, E-mail: dej122842@gmail.com
2015-11-15
Highlights: • High precision ray tracing is formulated using power series techniques. • Ray tracing is possible for fields generated by solution to laplace's equation. • Spatial and temporal orders of 4–10 are included. • Precisions in test geometries of hemispherical deflector analyzer of ∼10{sup −20} have been obtained. • This solution offers a considerable extension to the ray tracing accuracy over the current state of art. - Abstract: With the recent availability of a high order FDM solution to the curved boundary value problem, it is now possible to determine potentials in such geometries with considerably greater accuracy than had been available with the FDM method. In order for the algorithms used in the accurate potential calculations to be useful in ray tracing, an integration of those algorithms needs to be placed into the ray trace process itself. The object of this paper is to incorporate these algorithms into a solution of the equations of motion of the ray and, having done this, to demonstrate its efficacy. The algorithm incorporation has been accomplished by using power series techniques and the solution constructed has been tested by tracing the medial ray through concentric sphere geometries. The testing has indicated that precisions of ray calculations of 10{sup −20} are now possible. This solution offers a considerable extension to the ray tracing accuracy over the current state of art.
The precise adjustment of coil location for transcranial magnetic stimulation during dynamic motion.
Kitamura, Taku; Yaeshima, Katsutoshi; Yamamoto, Shin-Ichiro; Kawashima, Noritaka
2013-01-01
Transcranial magnetic stimulation (TMS) to the cerebral cortex is a major in vitro technique that is used in the field of neurophysiology. The magnitude of the motor-evoked potentials (MEP) that are elicited by TMS to the primary motor cortex reflect the excitability of the corticospinal pathway. MEPs are very sensitive to the scalp location of the stimulus coil, especially when corticospinal excitability is recorded during walking or other dynamic motions. In this study, we created a coil navigational system that consisted of three-dimensional motion analysis cameras, rigid bodies on the head and coil, and programming software. In order to evaluate the feasibility of the use of our system, pseudo TMS was applied during treadmill walking with or without the navigational system. As a result, we found that the variances due to coil location and/or distance from the target site were reduced with our system. This technique enabled us to realize high precision and accuracy in coil placement, even during dynamic motion.
High precision neutron polarization for PERC
International Nuclear Information System (INIS)
Klauser, C.
2013-01-01
The decay of the free neutron into a proton, an electron and an anti-electron neutrino offers a simple system to study the semi-leptonic weak decay. High precision measurements of angular correlation coefficients of this decay provide the opportunity to test the standard model on the low energy frontier. The Proton Electron Radiation Channel PERC is part of a new generation of expriments pushing the accuracy of such an angular correlation coefficient measurement towards 10 -4 . Past experiments have been limited to an accuracy of 10 -3 with uncertainties on the neutron polarization as one of the leading systematic errors. This thesis focuses on the development of a stable, highly precise neutron polarization for a large, divergent cold neutron beam. A diagnostic tool that provides polarization higher than 99.99 % and analyzes with an accuracy of 10 -4 , the Opaque Test Bench, is presented and validated. It consists of two highly opaque polarized helium cells. The Opaque Test Bench reveals depolarizing effects in polarizing supermirrors commonly used for polarization in neutron decay experiments. These effects are investigated in detail. They are due to imperfect lateral magnetization in supermirror layers and can be minimized by significantly increased magnetizing fields and low incidence angle and supermirror factor m. A subsequent test in the crossed (X-SM) geometry demonstrated polarizations up to 99.97% from supermirrors only, improving neutron polarization with supermirrors by an order of magnitude. The thesis also discusses other neutron optical components of the PERC beamline: Monte-Carlo simulations of the beamline under consideration of the primary guide are carried out. In addition, calculation shows that PERC would statistically profit from an installation at the European Spallation source. Furthermore, beamline components were tested. A radio-frequency spin flipper was confirmed to work with an efficiency higher than 0.9999. (author) [de
Autonomous vehicle navigation utilizing fuzzy controls concepts for a next generation wheelchair.
Hansen, J D; Barrett, S F; Wright, C H G; Wilcox, M
2008-01-01
Three different positioning techniques were investigated to create an autonomous vehicle that could accurately navigate towards a goal: Global Positioning System (GPS), compass dead reckoning, and Ackerman steering. Each technique utilized a fuzzy logic controller that maneuvered a four-wheel car towards a target. The reliability and the accuracy of the navigation methods were investigated by modeling the algorithms in software and implementing them in hardware. To implement the techniques in hardware, positioning sensors were interfaced to a remote control car and a microprocessor. The microprocessor utilized the sensor measurements to orient the car with respect to the target. Next, a fuzzy logic control algorithm adjusted the front wheel steering angle to minimize the difference between the heading and bearing. After minimizing the heading error, the car maintained a straight steering angle along its path to the final destination. The results of this research can be used to develop applications that require precise navigation. The design techniques can also be implemented on alternate platforms such as a wheelchair to assist with autonomous navigation.
High precision spectrophotometric analysis of thorium
International Nuclear Information System (INIS)
Palmieri, H.E.L.
1984-01-01
An accurate and precise determination of thorium is proposed. Precision of about 0,1% is required for the determination of macroquantities of thorium when processed. After an extensive literature search concerning this subject, spectrophotometric titration has been chosen, using dissodium ethylenediaminetetraacetate (EDTA) solution and alizarin-S as indicator. In order to obtain such a precision, an amount of 0,025 M EDTA solution precisely measured has been added and the titration was completed with less than 5 ml of 0,0025 M EDTA solution. It is usual to locate the end-point graphically, by plotting added titrant versus absorbance. The non-linear minimum square fit, using the Fletcher e Powell's minimization process and a computer programme. Besides the equivalence point, other parameters of titration were determined: the indicator concentration, the absorbance of the metal-indicator complex, and the stability constants of the metal-indicator and the metal-EDTA complexes. (Author) [pt
Jiang, Taoran; Zhu, Ming; Zan, Tao; Gu, Bin; Li, Qingfeng
2017-08-01
In perforator flap transplantation, dissection of the perforator is an important but difficult procedure because of the high variability in vascular anatomy. Preoperative imaging techniques could provide substantial information about vascular anatomy; however, it cannot provide direct guidance for surgeons during the operation. In this study, a navigation system (NS) was established to overlie a vascular map on surgical sites to further provide a direct guide for perforator flap transplantation. The NS was established based on computed tomographic angiography and augmented reality techniques. A virtual vascular map was reconstructed according to computed tomographic angiography data and projected onto real patient images using ARToolKit software. Additionally, a screw-fixation marker holder was created to facilitate registration. With the use of a tracking and display system, we conducted the NS on an animal model and measured the system error on a rapid prototyping model. The NS assistance allowed for correct identification, as well as a safe and precise dissection of the perforator. The mean value of the system error was determined to be 3.474 ± 1.546 mm. Augmented reality-based NS can provide precise navigation information by directly displaying a 3-dimensional individual anatomical virtual model onto the operative field in real time. It will allow rapid identification and safe dissection of a perforator in free flap transplantation surgery.
Improving Canada's Marine Navigation System through e-Navigation
Directory of Open Access Journals (Sweden)
Daniel Breton
2016-06-01
The conclusion proposed is that on-going work with key partners and stakeholders can be used as the primary mechanism to identify e-Navigation related innovation and needs, and to prioritize next steps. Moving forward in Canada, implementation of new e-navigation services will continue to be stakeholder driven, and used to drive improvements to Canada's marine navigation system.
Liu, Yahui; Fan, Xiaoqian; Lv, Chen; Wu, Jian; Li, Liang; Ding, Dawei
2018-02-01
Information fusion method of INS/GPS navigation system based on filtering technology is a research focus at present. In order to improve the precision of navigation information, a navigation technology based on Adaptive Kalman Filter with attenuation factor is proposed to restrain noise in this paper. The algorithm continuously updates the measurement noise variance and processes noise variance of the system by collecting the estimated and measured values, and this method can suppress white noise. Because a measured value closer to the current time would more accurately reflect the characteristics of the noise, an attenuation factor is introduced to increase the weight of the current value, in order to deal with the noise variance caused by environment disturbance. To validate the effectiveness of the proposed algorithm, a series of road tests are carried out in urban environment. The GPS and IMU data of the experiments were collected and processed by dSPACE and MATLAB/Simulink. Based on the test results, the accuracy of the proposed algorithm is 20% higher than that of a traditional Adaptive Kalman Filter. It also shows that the precision of the integrated navigation can be improved due to the reduction of the influence of environment noise.
Directory of Open Access Journals (Sweden)
A. V. Fomichev
2015-01-01
Full Text Available In accordance with the structural features of small-size unmanned aerial vehicle (UAV, and considering the feasibility of this project, the article studies an integrated inertial-satellite navigation system (INS. The INS algorithm development is based on the method of indirect filtration and principle of loosely coupled combination of output data on UAV positions and velocity. Data on position and velocity are provided from the strapdown inertial navigation system (SINS and satellite navigation system (GPS. A difference between the output flows of measuring data on position and velocity provided from the SINS and GPS is used to evaluate SINS errors by means of the basic algorithm of Kalman filtering. Then the outputs of SINS are revised. The INS possesses the following advantages: a simpler mathematical model of Kalman filtering, high reliability, two independently operating navigation systems, and high redundancy of available navigation information.But in case of loosely coupled scheme, INS can meet the challenge of high precision and reliability of navigation only when the SINS and GPS operating conditions are normal all the time. The proposed INS is used with UAV moving in complex environment due to obstacles available, severe natural climatic conditions, etc. This case expects that it is impossible for UAV to receive successful GPS-signals frequently. In order to solve this problem, was developed an algorithm for rapid compensation for errors of INS information, which could effectively solve the problem of failure of the navigation system in case there are no GPS-signals .Since it is almost impossible to obtain the data of the real trajectory in practice, in the course of simulation in accordance with the kinematic model of the UAV and the complex environment of the terrain, the flight path generator is used to produce the flight path. The errors of positions and velocities are considered as an indicator of the INS effectiveness. The results
Observing exoplanet populations with high-precision astrometry
Sahlmann, Johannes
2012-06-01
This thesis deals with the application of the astrometry technique, consisting in measuring the position of a star in the plane of the sky, for the discovery and characterisation of extra-solar planets. It is feasible only with a very high measurement precision, which motivates the use of space observatories, the development of new ground-based astronomical instrumentation and of innovative data analysis methods: The study of Sun-like stars with substellar companions using CORALIE radial velocities and HIPPARCOS astrometry leads to the determination of the frequency of close brown dwarf companions and to the discovery of a dividing line between massive planets and brown dwarf companions; An observation campaign employing optical imaging with a very large telescope demonstrates sufficient astrometric precision to detect planets around ultra-cool dwarf stars and the first results of the survey are presented; Finally, the design and initial astrometric performance of PRIMA, ! a new dual-feed near-infrared interferometric observing facility for relative astrometry is presented.
Helicopter precision approach capability using the Global Positioning System
Kaufmann, David N.
1992-01-01
The period between 1 July and 31 December, 1992, was spent developing a research plan as well as a navigation system document and flight test plan to investigate helicopter precision approach capability using the Global Positioning System (GPS). In addition, all hardware and software required for the research was acquired, developed, installed, and verified on both the test aircraft and the ground-based reference station.
Navigating on handheld displays: Dynamic versus Static Keyhole Navigation
Mehra, S.; Werkhoven, P.; Worring, M.
2006-01-01
Handheld displays leave little space for the visualization and navigation of spatial layouts representing rich information spaces. The most common navigation method for handheld displays is static peephole navigation: The peephole is static and we move the spatial layout behind it (scrolling). A
High-precision thickness measurements using beta backscatter
International Nuclear Information System (INIS)
Heckman, R.V.
1978-11-01
A two-axis, automated fixture for use with a high-intensity Pm-147 source and a photomultiplier-scintillation beta-backscatter probe for making thickness measurements has been designed and built. A custom interface was built to connect the system to a minicomputer, and software was written to position the tables, control the probe, and make the measurements. Measurements can be made in less time with much greater precision than by the method previously used
Digitalization of highly precise fluxgate magnetometers
DEFF Research Database (Denmark)
Cerman, Ales; Kuna, A.; Ripka, P.
2005-01-01
This paper describes the theory behind all three known ways of digitalizing the fluxgate magnetometers: analogue magnetometers with digitalized output using high resolution ADC, application of the delta-sigma modulation to the sensor feedback loop and fully digital signal detection. At present time...... the Delta-Sigma ADCs are mostly used for the digitalization of the highly precise fluxgate magnetorneters. The relevant part of the paper demonstrates some pitfalls of their application studied during the design of the magnetometer for the new Czech scientific satellite MIMOSA. The part discussing...... the application of the A-E modulation to the sensor feedback loop theoretically derives the main advantage of this method-increasing of the modulation order and shows its real potential compared to the analog magnetometer with consequential digitalization. The comparison is realized on the modular magnetometer...
Autonomous self-navigating drug-delivery vehicles: from science fiction to reality.
Petrenko, Valery A
2017-12-01
Low efficacy of targeted nanomedicines in biological experiments enforced us to challenge the traditional concept of drug targeting and suggest a paradigm of 'addressed self-navigating drug-delivery vehicles,' in which affinity selection of targeting peptides and vasculature-directed in vivo phage screening is replaced by the migration selection, which explores ability of 'promiscuous' phages and their proteins to migrate through the tumor-surrounding cellular barriers, using a 'hub and spoke' delivery strategy, and penetrate into the tumor affecting the diverse tumor cell population. The 'self-navigating' drug-delivery paradigm can be used as a theoretical and technical platform in design of a novel generation of molecular medications and imaging probes for precise and personal medicine. [Formula: see text].
International Nuclear Information System (INIS)
Schnurr, C.; Nessler, J.; Koenig, D.P.; Meyer, C.; Schild, H.H.; Koebke, J.
2009-01-01
The existing studies concerning image-free navigated implantation of hip resurfacing arthroplasty are based on analysis of the accuracy of conventional biplane radiography. Studies have shown that these measurements in biplane radiography are imprecise and that precision is improved by use of three-dimensional (3D) computer tomography (CT) scans. To date, the accuracy of image-free navigation devices for hip resurfacing has not been investigated using CT scans, and anteversion accuracy has not been assessed at all. Furthermore, no study has tested the reliability of the navigation software concerning the automatically calculated implant position. The purpose of our study was to analyze the accuracy of varus-valgus and anteversion using an image-free hip resurfacing navigation device. The reliability of the software-calculated implant position was also determined. A total of 32 femoral hip resurfacing components were implanted on embalmed human femurs using an image-free navigation device. In all, 16 prostheses were implanted with the proposed position generated by the navigation software; the 16 prostheses were inserted in an optimized valgus position. A 3D CT scan was undertaken before and after operation. The difference between the measured and planned varus-valgus angle averaged 1 deg (mean±standard deviation (SD): group I, 1 deg±2 deg; group II, 1 deg±1 deg). The mean±SD difference between femoral neck anteversion and anteversion of the implant was 4 deg (group I, 4 deg±4 deg; group II, 4 deg±3 deg). The software-calculated implant position differed 7 deg±8 deg from the measured neck-shaft angle. These measured accuracies did not differ significantly between the two groups. Our study proved the high accuracy of the navigation device concerning the most important biomechanical factor: the varus-valgus angle. The software calculation of the proposed implant position has been shown to be inaccurate and needs improvement. Hence, manual adjustment of the
Fault-tolerant Sensor Fusion for Marine Navigation
DEFF Research Database (Denmark)
Blanke, Mogens
2006-01-01
Reliability of navigation data are critical for steering and manoeuvring control, and in particular so at high speed or in critical phases of a mission. Should faults occur, faulty instruments need be autonomously isolated and faulty information discarded. This paper designs a navigation solution...... where essential navigation information is provided even with multiple faults in instrumentation. The paper proposes a provable correct implementation through auto-generated state-event logics in a supervisory part of the algorithms. Test results from naval vessels document the performance and shows...... events where the fault-tolerant sensor fusion provided uninterrupted navigation data despite temporal instrument defects...
MRPC-PET: A new technique for high precision time and position measurements
International Nuclear Information System (INIS)
Doroud, K.; Hatzifotiadou, D.; Li, S.; Williams, M.C.S.; Zichichi, A.; Zuyeuski, R.
2011-01-01
The purpose of this paper is to consider a new technology for medical diagnosis: the MRPC-PET. This technology allows excellent time resolution together with 2-D position information thus providing a fundamental step in this field. The principle of this method is based on the Multigap Resistive Plate Chamber (MRPC) capable of high precision time measurements. We have previously found that the route to precise timing is differential readout (this requires matching anode and cathode strips); thus crossed strip readout schemes traditionally used for 2-D readout cannot be exploited. In this paper we consider the time difference from the two ends of the strip to provide a high precision measurement along the strip; the average time gives precise timing. The MRPC-PET thus provides a basic step in the field of medical technology: excellent time resolution together with 2-D position measurement.
The use of virtual surgical planning and navigation in the treatment of orbital trauma
Directory of Open Access Journals (Sweden)
Alan Scott Herford
2017-02-01
Full Text Available Virtual surgical planning (VSP has recently been introduced in craniomaxillofacial surgery with the goal of improving efficiency and precision for complex surgical operations. Among many indications, VSP can also be applied for the treatment of congenital and acquired craniofacial defects, including orbital fractures. VSP permits the surgeon to visualize the complex anatomy of craniofacial region, showing the relationship between bone and neurovascular structures. It can be used to design and print using three-dimensional (3D printing technology and customized surgical models. Additionally, intraoperative navigation may be useful as an aid in performing the surgery. Navigation is useful for both the surgical dissection as well as to confirm the placement of the implant. Navigation has been found to be especially useful for orbit and sinus surgery. The present paper reports a case describing the use of VSP and computerized navigation for the reconstruction of a large orbital floor defect with a custom implant.
Calibration of gyro G-sensitivity coefficients with FOG monitoring on precision centrifuge
Lu, Jiazhen; Yang, Yanqiang; Li, Baoguo; Liu, Ming
2017-07-01
The advantages of mechanical gyros, such as high precision, endurance and reliability, make them widely used as the core parts of inertial navigation systems (INS) utilized in the fields of aeronautics, astronautics and underground exploration. In a high-g environment, the accuracy of gyros is degraded. Therefore, the calibration and compensation of the gyro G-sensitivity coefficients is essential when the INS operates in a high-g environment. A precision centrifuge with a counter-rotating platform is the typical equipment for calibrating the gyro, as it can generate large centripetal acceleration and keep the angular rate close to zero; however, its performance is seriously restricted by the angular perturbation in the high-speed rotating process. To reduce the dependence on the precision of the centrifuge and counter-rotating platform, an effective calibration method for the gyro g-sensitivity coefficients under fiber-optic gyroscope (FOG) monitoring is proposed herein. The FOG can efficiently compensate spindle error and improve the anti-interference ability. Harmonic analysis is performed for data processing. Simulations show that the gyro G-sensitivity coefficients can be efficiently estimated to up to 99% of the true value and compensated using a lookup table or fitting method. Repeated tests indicate that the G-sensitivity coefficients can be correctly calibrated when the angular rate accuracy of the precision centrifuge is as low as 0.01%. Verification tests are performed to demonstrate that the attitude errors can be decreased from 0.36° to 0.08° in 200 s. The proposed measuring technology is generally applicable in engineering, as it can reduce the accuracy requirements for the centrifuge and the environment.
Local high precision 3D measurement based on line laser measuring instrument
Zhang, Renwei; Liu, Wei; Lu, Yongkang; Zhang, Yang; Ma, Jianwei; Jia, Zhenyuan
2018-03-01
In order to realize the precision machining and assembly of the parts, the geometrical dimensions of the surface of the local assembly surfaces need to be strictly guaranteed. In this paper, a local high-precision three-dimensional measurement method based on line laser measuring instrument is proposed to achieve a high degree of accuracy of the three-dimensional reconstruction of the surface. Aiming at the problem of two-dimensional line laser measuring instrument which lacks one-dimensional high-precision information, a local three-dimensional profile measuring system based on an accurate single-axis controller is proposed. First of all, a three-dimensional data compensation method based on spatial multi-angle line laser measuring instrument is proposed to achieve the high-precision measurement of the default axis. Through the pretreatment of the 3D point cloud information, the measurement points can be restored accurately. Finally, the target spherical surface is needed to make local three-dimensional scanning measurements for accuracy verification. The experimental results show that this scheme can get the local three-dimensional information of the target quickly and accurately, and achieves the purpose of gaining the information and compensating the error for laser scanner information, and improves the local measurement accuracy.
Novel catalytic micromotor of porous zeolitic imidazolate framework-67 for precise drug delivery.
Wang, Linlin; Zhu, Hongli; Shi, Ying; Ge, You; Feng, Xiaomiao; Liu, Ruiqing; Li, Yi; Ma, Yanwen; Wang, Lianhui
2018-06-07
Micromotors hold promise as drug carriers for targeted drug delivery owing to the characteristics of self-propulsion and directional navigation. However, several defects still exist, including high cost, short movement life, low drug loading and slow release rate. Herein, a novel catalytic micromotor based on porous zeolitic imidazolate framework-67 (ZIF-67) synthesized by a greatly simplified wet chemical method assisted with ultrasonication is described as an efficient anticancer drug carrier. These porous micromotors display effective autonomous motion in hydrogen peroxide and long durable movement life of up to 90 min. Moreover, the multifunctional micromotor ZIF-67/Fe3O4/DOX exhibits excellent performance in precise drug delivery under external magnetic field with high drug loading capacity of fluorescent anticancer drug DOX up to 682 μg mg-1 owing to its porous nature, high surface area and rapid drug release based on dual stimulus of catalytic reaction and solvent effects. Therefore, these porous ZIF-67-based catalytic micromotors combine the domains of metal-organic frameworks (MOFs) and micomotors, thus developing potential resources for micromotors and holding great potential as label-free and precisely controlled high-quality candidates of drug delivery systems for biomedical applications.
High precision timing in a FLASH
Energy Technology Data Exchange (ETDEWEB)
Hoek, Matthias; Cardinali, Matteo; Dickescheid, Michael; Schlimme, Soeren; Sfienti, Concettina; Spruck, Bjoern; Thiel, Michaela [Institut fuer Kernphysik, Johannes Gutenberg-Universitaet Mainz (Germany)
2016-07-01
A segmented highly precise start counter (FLASH) was designed and constructed at the Institute for Nuclear Physics in Mainz. Besides determining a precise reference time, a Time-of-Flight measurement can be performed with two identical FLASH units. Thus, particle identification can be provided for mixed hadron beam environments. The detector design is based on the detection of Cherenkov light produced in fused silica radiator bars with fast multi-anode MCP-PMTs. The segmentation of the radiator improves the timing resolution while allowing a coarse position resolution along one direction. Both, the arrival time and the Time-over-Threshold are determined by the readout electronics, which enables walk correction of the arrival time. The performance of two FLASH units was investigated in test experiments at the Mainz Microton (MAMI) using an electron beam with an energy of 855 MeV and at CERN's PS T9 beam line with a mixed hadron beam with momenta between 3-8 GeV/c. Effective Time-walk correction methods based on Time-over-Threshold were developed for the data analysis. The achieved Time-Of-Flight resolution after applying all corrections was found to be 70 ps. Furthermore, the PID and position resolution capabilities are discussed in this contribution.
Theoretical Limits of Lunar Vision Aided Navigation with Inertial Navigation System
2015-03-26
THEORETICAL LIMITS OF LUNAR VISION AIDED NAVIGATION WITH INERTIAL NAVIGATION SYSTEM THESIS David W. Jones, Capt, USAF AFIT-ENG-MS-15-M-020 DEPARTMENT...Government and is not subject to copyright protection in the United States. AFIT-ENG-MS-15-M-020 THEORETICAL LIMITS OF LUNAR VISION AIDED NAVIGATION WITH...DISTRIBUTION UNLIMITED. AFIT-ENG-MS-15-M-020 THEORETICAL LIMITS OF LUNAR VISION AIDED NAVIGATION WITH INERTIAL NAVIGATION SYSTEM THESIS David W. Jones
SINS/CNS Nonlinear Integrated Navigation Algorithm for Hypersonic Vehicle
Directory of Open Access Journals (Sweden)
Yong-jun Yu
2015-01-01
Full Text Available Celestial Navigation System (CNS has characteristics of accurate orientation and strong autonomy and has been widely used in Hypersonic Vehicle. Since the CNS location and orientation mainly depend upon the inertial reference that contains errors caused by gyro drifts and other error factors, traditional Strap-down Inertial Navigation System (SINS/CNS positioning algorithm setting the position error between SINS and CNS as measurement is not effective. The model of altitude azimuth, platform error angles, and horizontal position is designed, and the SINS/CNS tightly integrated algorithm is designed, in which CNS altitude azimuth is set as measurement information. GPF (Gaussian particle filter is introduced to solve the problem of nonlinear filtering. The results of simulation show that the precision of SINS/CNS algorithm which reaches 130 m using three stars is improved effectively.
Lee, Taehwa; Luo, Wei; Li, Qiaochu; Demirci, Hakan; Guo, L Jay
2017-10-01
Beyond the implementation of the photoacoustic effect to photoacoustic imaging and laser ultrasonics, this study demonstrates a novel application of the photoacoustic effect for high-precision cavitation treatment of tissue using laser-induced focused ultrasound. The focused ultrasound is generated by pulsed optical excitation of an efficient photoacoustic film coated on a concave surface, and its amplitude is high enough to produce controllable microcavitation within the focal region (lateral focus <100 µm). Such microcavitation is used to cut or ablate soft tissue in a highly precise manner. This work demonstrates precise cutting of tissue-mimicking gels as well as accurate ablation of gels and animal eye tissues. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Lee, Kenneth; Hoti, Kreshnik; Hughes, Jeffery David; Emmerton, Lynne M
2015-12-29
The Internet provides a platform to access health information and support self-management by consumers with chronic health conditions. Despite recognized barriers to accessing Web-based health information, there is a lack of research quantitatively exploring whether consumers report difficulty finding desired health information on the Internet and whether these consumers would like assistance (ie, navigational needs). Understanding navigational needs can provide a basis for interventions guiding consumers to quality Web-based health resources. We aimed to (1) estimate the proportion of consumers with navigational needs among seekers of Web-based health information with chronic health conditions, (2) describe Web-based health information-seeking behaviors, level of patient activation, and level of eHealth literacy among consumers with navigational needs, and (3) explore variables predicting navigational needs. A questionnaire was developed based on findings from a qualitative study on Web-based health information-seeking behaviors and navigational needs. This questionnaire also incorporated the eHealth Literacy Scale (eHEALS; a measure of self-perceived eHealth literacy) and PAM-13 (a measure of patient activation). The target population was consumers of Web-based health information with chronic health conditions. We surveyed a sample of 400 Australian adults, with recruitment coordinated by Qualtrics. This sample size was required to estimate the proportion of consumers identified with navigational needs with a precision of 4.9% either side of the true population value, with 95% confidence. A subsample was invited to retake the survey after 2 weeks to assess the test-retest reliability of the eHEALS and PAM-13. Of 514 individuals who met our eligibility criteria, 400 (77.8%) completed the questionnaire and 43 participants completed the retest. Approximately half (51.3%; 95% CI 46.4-56.2) of the population was identified with navigational needs. Participants with
A novel power source for high-precision, highly efficient micro w-EDM
International Nuclear Information System (INIS)
Chen, Shun-Tong; Chen, Chi-Hung
2015-01-01
The study presents the development of a novel power source for high-precision, highly efficient machining of micropart microstructures using micro wire electrical discharge machining (w-EDM). A novel power source based on a pluri resistance–capacitance (pRC) circuit that can generate a high-frequency, high-peak current with a short pulse train is proposed and designed to enhance the performance of micro w-EDM processes. Switching between transistors is precisely controlled in the designed power source to create a high-frequency short-pulse train current. Various microslot cutting tests in both aluminum and copper alloys are conducted. Experimental results demonstrate that the pRC power source creates instant spark erosion resulting in markedly less material for removal, diminishing discharge crater size, and consequently an improved surface finish. A new evaluation approach for spark erosion ability (SEA) to assess the merits of micro EDM power sources is also proposed. In addition to increasing the speed of micro w-EDM by increasing wire feed rates by 1.6 times the original feed rate, the power source is more appropriate for machining micropart microstructures since there is less thermal breaking. Satisfactory cutting of an elaborate miniature hook-shaped structure and a high-aspect ratio microstructure with a squared-pillar array also reveal that the developed pRC power source is effective, and should be very useful in the manufacture of intricate microparts. (paper)
Multi-rover navigation on the lunar surface
Dabrowski, Borys; Banaszkiewicz, Marek
2008-07-01
The paper presents a method of determination an accurate position of a target (rover, immobile sensor, astronaut) on surface of the Moon or other celestial body devoid of navigation infrastructure (like Global Positioning System), by using a group of self-calibrating rovers, which serves as mobile reference points. The rovers are equipped with low-precision clocks synchronized by external broadcasting signal, to measure the moments of receiving radio signals sent by localized target. Based on the registered times, distances between transmitter and receivers installed on beacons are calculated. Each rover determines and corrects its own absolute position and orientation by using odometry navigation and measurements of relative distances and angles to other mobile reference points. Accuracy of navigation has been improved by the use of a calibration algorithm based on the extended Kalman filter, which uses internal encoder readings as inputs and relative measurements of distances and orientations between beacons as feedback information. The key idea in obtaining reliable values of absolute position and orientation of beacons is to first calibrate one of the rovers, using the remaining ones as reference points and then allow the whole group to move together and calibrate all the rovers in-motion. We consider a number of cases, in which basic modeling parameters such as terrain roughness, formation size and shape as well as availability of distance and angle measurements are varied.
High-precision relative position and attitude measurement for on-orbit maintenance of spacecraft
Zhu, Bing; Chen, Feng; Li, Dongdong; Wang, Ying
2018-02-01
In order to realize long-term on-orbit running of satellites, space stations, etc spacecrafts, in addition to the long life design of devices, The life of the spacecraft can also be extended by the on-orbit servicing and maintenance. Therefore, it is necessary to keep precise and detailed maintenance of key components. In this paper, a high-precision relative position and attitude measurement method used in the maintenance of key components is given. This method mainly considers the design of the passive cooperative marker, light-emitting device and high resolution camera in the presence of spatial stray light and noise. By using a series of algorithms, such as background elimination, feature extraction, position and attitude calculation, and so on, the high precision relative pose parameters as the input to the control system between key operation parts and maintenance equipment are obtained. The simulation results show that the algorithm is accurate and effective, satisfying the requirements of the precision operation technique.
Trial of accelerator cells machining with high precision and high efficiency at Okayama region
International Nuclear Information System (INIS)
Yoshikawa, Mitsuo; Yoden, Hiroyuki; Yokomizo, Seiichi; Sumida, Tsuneto; Kunishida, Jun; Oshita, Isao
2005-01-01
In the framework of the project 'Promotion of Science and Technology in Regional Areas' by the Ministry of Education, Culture, Sports, Science and Technology, we have prepared a special apparatus for machining accelerator cells with a high precision and a high efficiency for the future linear collider. A machining with as small an error as 2 micrometers has been realized. Necessary time to finish one accelerator cell is reduced from 128 minutes to 34 minutes due to the suppression of the heating of the object at the machining. If newly developed one chuck method was employed, the precision and efficiency would be further improved. By cutting at both sides of the spindle, the necessary time for machining would be reduced by half. (author)
HIGH PRECISION ROVIBRATIONAL SPECTROSCOPY OF OH{sup +}
Energy Technology Data Exchange (ETDEWEB)
Markus, Charles R.; Hodges, James N.; Perry, Adam J.; Kocheril, G. Stephen; McCall, Benjamin J. [Department of Chemistry, University of Illinois, Urbana, IL 61801 (United States); Müller, Holger S. P., E-mail: bjmccall@illinois.edu [I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln (Germany)
2016-02-01
The molecular ion OH{sup +} has long been known to be an important component of the interstellar medium. Its relative abundance can be used to indirectly measure cosmic ray ionization rates of hydrogen, and it is the first intermediate in the interstellar formation of water. To date, only a limited number of pure rotational transitions have been observed in the laboratory making it necessary to indirectly calculate rotational levels from high-precision rovibrational spectroscopy. We have remeasured 30 transitions in the fundamental band with MHz-level precision, in order to enable the prediction of a THz spectrum of OH{sup +}. The ions were produced in a water cooled discharge of O{sub 2}, H{sub 2}, and He, and the rovibrational transitions were measured with the technique Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy. These values have been included in a global fit of field free data to a {sup 3}Σ{sup −} linear molecule effective Hamiltonian to determine improved spectroscopic parameters which were used to predict the pure rotational transition frequencies.
Research on the high-precision non-contact optical detection technology for banknotes
Jin, Xiaofeng; Liang, Tiancai; Luo, Pengfeng; Sun, Jianfeng
2015-09-01
The technology of high-precision laser interferometry was introduced for optical measurement of the banknotes in this paper. Taking advantage of laser short wavelength and high sensitivity, information of adhesive tape and cavity about the banknotes could be checked efficiently. Compared with current measurement devices, including mechanical wheel measurement device, Infrared measurement device, ultrasonic measurement device, the laser interferometry measurement has higher precision and reliability. This will improve the ability of banknotes feature information in financial electronic equipment.
Closed-Loop Targeted Memory Reactivation during Sleep Improves Spatial Navigation.
Shimizu, Renee E; Connolly, Patrick M; Cellini, Nicola; Armstrong, Diana M; Hernandez, Lexus T; Estrada, Rolando; Aguilar, Mario; Weisend, Michael P; Mednick, Sara C; Simons, Stephen B
2018-01-01
Sounds associated with newly learned information that are replayed during non-rapid eye movement (NREM) sleep can improve recall in simple tasks. The mechanism for this improvement is presumed to be reactivation of the newly learned memory during sleep when consolidation takes place. We have developed an EEG-based closed-loop system to precisely deliver sensory stimulation at the time of down-state to up-state transitions during NREM sleep. Here, we demonstrate that applying this technology to participants performing a realistic navigation task in virtual reality results in a significant improvement in navigation efficiency after sleep that is accompanied by increases in the spectral power especially in the fast (12-15 Hz) sleep spindle band. Our results show promise for the application of sleep-based interventions to drive improvement in real-world tasks.
A Lane-Level LBS System for Vehicle Network with High-Precision BDS/GPS Positioning
Guo, Chi; Guo, Wenfei; Cao, Guangyi; Dong, Hongbo
2015-01-01
In recent years, research on vehicle network location service has begun to focus on its intelligence and precision. The accuracy of space-time information has become a core factor for vehicle network systems in a mobile environment. However, difficulties persist in vehicle satellite positioning since deficiencies in the provision of high-quality space-time references greatly limit the development and application of vehicle networks. In this paper, we propose a high-precision-based vehicle network location service to solve this problem. The major components of this study include the following: (1) application of wide-area precise positioning technology to the vehicle network system. An adaptive correction message broadcast protocol is designed to satisfy the requirements for large-scale target precise positioning in the mobile Internet environment; (2) development of a concurrence service system with a flexible virtual expansion architecture to guarantee reliable data interaction between vehicles and the background; (3) verification of the positioning precision and service quality in the urban environment. Based on this high-precision positioning service platform, a lane-level location service is designed to solve a typical traffic safety problem. PMID:25755665
Precise Orbit Determination of QZS-1
Hugentobler, U.; Steigenberger, P.; Rodriguez-Solano, C.; Hauschild, A.
2011-12-01
QZS-1, the first satellite of the Japanese Quasi Zenith Satellite System (QZSS) was launched in September 2010. Transmission of the standard codes started in December 2010 and the satellite was declared healthy in June 2011. Five stations of the COoperative Network for GIOVE Observation (CONGO) were upgraded to provide QZSS tracking capability. These five stations provide the basis for the precise orbit determination (POD) of the QZS-1 spacecraft. The stability and consistency of different orbital arc lengths is analyzed based on orbit fit residuals, day boundary discontinuities, and Satellite Laser Ranging residuals. As QZS-1 simultaneously transmits navigation signals on three frequencies in the L1, L2, and L5 band, different ionosphere-free linear combinations can be formed. The differences of the orbits computed from these different observables (ionosphere-free linear combination of L1/L2 and L1/L5) as well as the stability of the differential code biases estimated within the POD are studied. Finally, results of the attitude determination based on the navigation signal transmission from two different antennas onboard QZS-1 are presented.
GPS Navigation Above 76,000 km for the MMS Mission
Winternitz, Luke; Bamford, Bill; Price, Samuel; Long, Anne; Farahmand, Mitra; Carpenter, Russell
2016-01-01
NASA's MMS mission, launched in March of 2015,consists of a controlled formation of four spin-stabilized spacecraft in similar highly elliptic orbits reaching apogee at radial distances of 12and 25 Earth radii in the first and second phases of the mission. Navigation for MMS is achieved independently onboard each spacecraft by processing GPS observables using NASA GSFC's Navigator GPS receiver and the Goddard Enhanced Onboard Navigation System (GEONS) extended Kalman filter software. To our knowledge, MMS constitutes, by far, the highest-altitude operational use of GPS to date and represents the culmination of over a decade of high-altitude GPS navigation research and development at NASA GSFC. In this paper we will briefly describe past and ongoing high-altitude GPS research efforts at NASA GSFC and elsewhere, provide details on the design of the MMS GPS navigation system, and present on-orbit performance data. We extrapolate these results to predict performance in the Phase 2b mission orbit, and conclude with a discussion of the implications of the MMS results for future high-altitude GPS navigation, which we believe to be broad and far-reaching.
Easy 3D Mapping for Indoor Navigation of Micro UAVs
DEFF Research Database (Denmark)
Schiøler, Henrik; Totu, Luminita Cristiana; La Cour-Harbo, Anders
2017-01-01
Indoor operation of micro air vehicles (UAS or UAV) is significantly simplified with the availability of some means for indoor localization as well as a sufficiently precise 3D map of the facility. Creation of 3D maps based on the available architectural information should on the one hand provide...... a map of sufficient precision and on the other limit complexity to a manageable level. This paper presents a box based approach for easy generation 3D maps to serve as the basis for indoor navigation of UAS. The basic building block employed is a 3D axis parallel box (APB). Unions of APBs constitute...... with arguments for pivotal design choices and a selection of examples....
Context-Aided Sensor Fusion for Enhanced Urban Navigation
Martí, Enrique David; Martín, David; García, Jesús; de la Escalera, Arturo; Molina, José Manuel; Armingol, José María
2012-01-01
The deployment of Intelligent Vehicles in urban environments requires reliable estimation of positioning for urban navigation. The inherent complexity of this kind of environments fosters the development of novel systems which should provide reliable and precise solutions to the vehicle. This article details an advanced GNSS/IMU fusion system based on a context-aided Unscented Kalman filter for navigation in urban conditions. The constrained non-linear filter is here conditioned by a contextual knowledge module which reasons about sensor quality and driving context in order to adapt it to the situation, while at the same time it carries out a continuous estimation and correction of INS drift errors. An exhaustive analysis has been carried out with available data in order to characterize the behavior of available sensors and take it into account in the developed solution. The performance is then analyzed with an extensive dataset containing representative situations. The proposed solution suits the use of fusion algorithms for deploying Intelligent Transport Systems in urban environments. PMID:23223080
International Nuclear Information System (INIS)
Sieskiewicz, A.; Mariak, Z.; Rogowski, M.; Lyson, T.
2008-01-01
Histopathological diagnosis of intraorbital tumors is of crucial value for planning further therapy. The aim of the study was to explore clinical utility of image-guided endoscopy for biopsy of orbital tumors. Trans-nasal endoscopic biopsy of intraorbital mass lesions was performed in 6 patients using a neuro-navigation system (Medtronic Stealth Station Treon plus). The CT and MRI 1 mm slice images were fused by the system in order to visualise both bony and soft tissue structures. The anatomic fiducial registration protocol was used during the procedure. All lesions were precisely localised and the biopsies could be taken from the representative part of the pathological mass. None of the patients developed aggravation of ocular symptoms after the procedure. The operative corridor as well as the size of orbital wall fenestration could be limited to a minimum. The accuracy of neuro-navigation remained high and stable during the entire procedure. The image-guided neuro-navigation system facilitated endoscopic localisation and biopsy of intraorbital tumors and contributed to the reduction of surgical trauma during the procedure. The technique was particularly useful in small, medially located, retrobulbar tumors and in unclear situations when the structure of the lesion resembled surrounding intraorbital tissue. (author)
Calibration of the precision high voltage dividers of the KATRIN experiment
Energy Technology Data Exchange (ETDEWEB)
Rest, Oliver [Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet Muenster (Germany); Collaboration: KATRIN-Collaboration
2016-07-01
The KATRIN (KArlsruhe TRItium Neutrino) experiment will measure the endpoint region of the tritium β decay spectrum to determine the neutrino mass with a sensitivity of 200 meV/c{sup 2}. To achieve this sub-eV sensitivity the energy of the decay electrons will be analyzed using a MAC-E type spectrometer. The retarding potential of the MAC-E-filter (up to -35 kV) has to be monitored with a relative precision of 3 . 10{sup -6}. For this purpose the potential will be measured directly via two custom made precision high voltage dividers, which were developed and constructed in cooperation with the Physikalisch-Technische Bundesanstalt Braunschweig. In order to determine the absolute values and the stability of the scale factors of the voltage dividers, regular calibration measurements are essential. Such measurements have been performed during the last years using several different methods. The poster gives an overview of the methods and results of the calibration of the precision high voltage dividers.
DEFF Research Database (Denmark)
Arnskov, Thomas; Elmholdt, Anders; Jensen, Kristian Hagemann
2018-01-01
This poster details the design and evaluation of Locomotion3 - a framework that allows users to freely alternate between real walking, walking-in-place (WIP), and a skateboard metaphor depending on whether navigation requires efficiency, precision, or both. The user study compared the framework t...
High precision determination of 16O in high Tc superconductors by DIGME
International Nuclear Information System (INIS)
Vickridge, I.; Tallon, J.; Presland, M.
1994-01-01
A method is described for measuring the 16 O content of high T c superconductors with better than 1% precision by exploiting the detection of gamma rays emitted when they are irradiated by an MeV deuterium beam. The method is presently less accurate than the widely used titration and thermogravimetric methods, however it is rapid, and may be applied to materials such as Tl-containing high T c superconductors which pose serious problems for the usual analytical methods. (orig.)
Development and simulation of microfluidic Wheatstone bridge for high-precision sensor
International Nuclear Information System (INIS)
Shipulya, N D; Konakov, S A; Krzhizhanovskaya, V V
2016-01-01
In this work we present the results of analytical modeling and 3D computer simulation of microfluidic Wheatstone bridge, which is used for high-accuracy measurements and precision instruments. We propose and simulate a new method of a bridge balancing process by changing the microchannel geometry. This process is based on the “etching in microchannel” technology we developed earlier (doi:10.1088/1742-6596/681/1/012035). Our method ensures a precise control of the flow rate and flow direction in the bridge microchannel. The advantage of our approach is the ability to work without any control valves and other active electronic systems, which are usually used for bridge balancing. The geometrical configuration of microchannels was selected based on the analytical estimations. A detailed 3D numerical model was based on Navier-Stokes equations for a laminar fluid flow at low Reynolds numbers. We investigated the behavior of the Wheatstone bridge under different process conditions; found a relation between the channel resistance and flow rate through the bridge; and calculated the pressure drop across the system under different total flow rates and viscosities. Finally, we describe a high-precision microfluidic pressure sensor that employs the Wheatstone bridge and discuss other applications in complex precision microfluidic systems. (paper)
Mars rover local navigation and hazard avoidance
Wilcox, B. H.; Gennery, D. B.; Mishkin, A. H.
1989-01-01
A Mars rover sample return mission has been proposed for the late 1990's. Due to the long speed-of-light delays between earth and Mars, some autonomy on the rover is highly desirable. JPL has been conducting research in two possible modes of rover operation, Computer-Aided Remote Driving and Semiautonomous Navigation. A recently-completed research program used a half-scale testbed vehicle to explore several of the concepts in semiautonomous navigation. A new, full-scale vehicle with all computational and power resources on-board will be used in the coming year to demonstrate relatively fast semiautonomous navigation. The computational and power requirements for Mars rover local navigation and hazard avoidance are discussed.
High-precision branching ratio measurement for the superallowed β+ emitter Ga62
Finlay, P.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Austin, R. A. E.; Bandyopadhyay, D.; Chaffey, A.; Chakrawarthy, R. S.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hyland, B.; Kanungo, R.; Leach, K. G.; Mattoon, C. M.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Ressler, J. J.; Sarazin, F.; Savajols, H.; Schumaker, M. A.; Wong, J.
2008-08-01
A high-precision branching ratio measurement for the superallowed β+ decay of Ga62 was performed at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. The 8π spectrometer, an array of 20 high-purity germanium detectors, was employed to detect the γ rays emitted following Gamow-Teller and nonanalog Fermi β+ decays of Ga62, and the SCEPTAR plastic scintillator array was used to detect the emitted β particles. Thirty γ rays were identified following Ga62 decay, establishing the superallowed branching ratio to be 99.858(8)%. Combined with the world-average half-life and a recent high-precision Q-value measurement for Ga62, this branching ratio yields an ft value of 3074.3±1.1 s, making Ga62 among the most precisely determined superallowed ft values. Comparison between the superallowed ft value determined in this work and the world-average corrected F tmacr value allows the large nuclear-structure-dependent correction for Ga62 decay to be experimentally determined from the CVC hypothesis to better than 7% of its own value, the most precise experimental determination for any superallowed emitter. These results provide a benchmark for the refinement of the theoretical description of isospin-symmetry breaking in A⩾62 superallowed decays.
Precise muon drift tube detectors for high background rate conditions
Energy Technology Data Exchange (ETDEWEB)
Engl, Albert
2011-08-04
The muon spectrometer of the ATLAS-experiment at the Large Hadron Collider consists of drift tube chambers, which provide the precise measurement of trajectories of traversing muons. In order to determine the momentum of the muons with high precision, the measurement of the position of the muon in a single tube has to be more accurate than {sigma}{<=}100 {mu}m. The large cross section of proton-proton-collisions and the high luminosity of the accelerator cause relevant background of neutrons and {gamma}s in the muon spectrometer. During the next decade a luminosity upgrade to 5.10{sup 34} cm{sup -2}s{sup -1} is planned, which will increase the background counting rates considerably. In this context this work deals with the further development of the existing drift chamber technology to provide the required accuracy of the position measurement under high background conditions. Two approaches of improving the drift tube chambers are described: - In regions of moderate background rates a faster and more linear drift gas can provide precise position measurement without changing the existing hardware. - At very high background rates drift tube chambers consisting of tubes with a diameter of 15 mm are a valuable candidate to substitute the CSC muon chambers. The single tube resolution of the gas mixture Ar:CO{sub 2}:N{sub 2} in the ratio of 96:3:1 Vol %, which is more linear and faster as the currently used drift gas Ar:CO{sub 2} in the ratio of 97:3 Vol %, was determined at the Cosmic Ray Measurement Facility at Garching and at high {gamma}-background counting rates at the Gamma Irradiation Facility at CERN. The alternative gas mixture shows similar resolution without background. At high background counting rates it shows better resolution as the standard gas. To analyse the data the various parts of the setup have to be aligned precisely to each other. The change to an alternative gas mixture allows the use of the existing hardware. The second approach are drift tubes
Design of high precision temperature control system for TO packaged LD
Liang, Enji; Luo, Baoke; Zhuang, Bin; He, Zhengquan
2017-10-01
Temperature is an important factor affecting the performance of TO package LD. In order to ensure the safe and stable operation of LD, a temperature control circuit for LD based on PID technology is designed. The MAX1978 and an external PID circuit are used to form a control circuit that drives the thermoelectric cooler (TEC) to achieve control of temperature and the external load can be changed. The system circuit has low power consumption, high integration and high precision,and the circuit can achieve precise control of the LD temperature. Experiment results show that the circuit can achieve effective and stable control of the laser temperature.
Research on Ship Trajectory Tracking with High Precision Based on LOS
Directory of Open Access Journals (Sweden)
Hengzhi Liu
2018-01-01
Full Text Available Aiming at how precise to track by LOS, a method is proposed. The method combines the advantages of LOS simplicity and intuition, easy parameter setting and good convergence, with the features of GPC softening, multi-step prediction, rolling optimization and excellent controllability and robustness. In order to verify the effectiveness of the method, the method is simulated by Matlab. The simulation’s results show that it makes ship tracking highly precise.
High-precision analogue peak detector for X-ray imaging applications
Dlugosz, Rafal Tomasz; Iniewski, Kris
2007-01-01
A new analogue high-precision peak detector is presented. Owing to its very low power consumption the circuit is particularly well suited for photon energy detection in multichannel receiver integrated circuits used in nuclear medicine.
Properties of the proton therapy. A high precision radiotherapy
International Nuclear Information System (INIS)
Anon.
2005-01-01
The proton therapy is a radiotherapy using protons beams. The protons present interesting characteristics but they need heavy technologies to be used, such particles accelerators, radiation protection wall and sophisticated technologies to reach the high precision allowed by their ballistic qualities (planning of treatment, beam conformation and patient positioning). (N.C.)
High-precision micro/nano-scale machining system
Kapoor, Shiv G.; Bourne, Keith Allen; DeVor, Richard E.
2014-08-19
A high precision micro/nanoscale machining system. A multi-axis movement machine provides relative movement along multiple axes between a workpiece and a tool holder. A cutting tool is disposed on a flexible cantilever held by the tool holder, the tool holder being movable to provide at least two of the axes to set the angle and distance of the cutting tool relative to the workpiece. A feedback control system uses measurement of deflection of the cantilever during cutting to maintain a desired cantilever deflection and hence a desired load on the cutting tool.
Computational Calorimetry: High-Precision Calculation of Host–Guest Binding Thermodynamics
2015-01-01
We present a strategy for carrying out high-precision calculations of binding free energy and binding enthalpy values from molecular dynamics simulations with explicit solvent. The approach is used to calculate the thermodynamic profiles for binding of nine small molecule guests to either the cucurbit[7]uril (CB7) or β-cyclodextrin (βCD) host. For these systems, calculations using commodity hardware can yield binding free energy and binding enthalpy values with a precision of ∼0.5 kcal/mol (95% CI) in a matter of days. Crucially, the self-consistency of the approach is established by calculating the binding enthalpy directly, via end point potential energy calculations, and indirectly, via the temperature dependence of the binding free energy, i.e., by the van’t Hoff equation. Excellent agreement between the direct and van’t Hoff methods is demonstrated for both host–guest systems and an ion-pair model system for which particularly well-converged results are attainable. Additionally, we find that hydrogen mass repartitioning allows marked acceleration of the calculations with no discernible cost in precision or accuracy. Finally, we provide guidance for accurately assessing numerical uncertainty of the results in settings where complex correlations in the time series can pose challenges to statistical analysis. The routine nature and high precision of these binding calculations opens the possibility of including measured binding thermodynamics as target data in force field optimization so that simulations may be used to reliably interpret experimental data and guide molecular design. PMID:26523125
33 CFR 2.36 - Navigable waters of the United States, navigable waters, and territorial waters.
2010-07-01
... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Navigable waters of the United States, navigable waters, and territorial waters. 2.36 Section 2.36 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY GENERAL JURISDICTION Jurisdictional Terms § 2.36 Navigable waters...
High precision frequency estimation for harpsichord tuning classification
Tidhar, D.; Mauch, M.; Dixon, S.
2010-01-01
We present a novel music signal processing task of classifying the tuning of a harpsichord from audio recordings of standard musical works. We report the results of a classification experiment involving six different temperaments, using real harpsichord recordings as well as synthesised audio data. We introduce the concept of conservative transcription, and show that existing high-precision pitch estimation techniques are sufficient for our task if combined with conservative transcription. In...
0011-0030.IEEE 754: 64 Bit Double Precision FloatsThis.pdf | 01 ...
Indian Academy of Sciences (India)
Home; public; Volumes; reso; 021; 01; 0011-0030.IEEE 754: 64 Bit Double Precision FloatsThis.pdf. 404! error. The page your are looking for can not be found! Please check the link or use the navigation bar at the top. YouTube; Twitter; Facebook; Blog. Academy News. IAS Logo. 29th Mid-year meeting. Posted on 19 ...
Drift chambers for a large-area, high-precision muon spectrometer
International Nuclear Information System (INIS)
Alberini, C.; Bari, G.; Cara Romeo, G.; Cifarelli, L.; Del Papa, C.; Iacobucci, G.; Laurenti, G.; Maccarrone, G.; Massam, T.; Motta, F.; Nania, R.; Perotto, E.; Prisco, G.; Willutsky, M.; Basile, M.; Contin, A.; Palmonari, F.; Sartorelli, G.
1987-01-01
We have tested two prototypes of high-precision drift chamber for a magnetic muon spectrometer. Results of the tests are presented, with special emphasis on their efficiency and spatial resolution as a function of particle rate. (orig.)
SKLUST device for high-precision gluing of MWPC
International Nuclear Information System (INIS)
Amaglobeli, N.S.; Burov, R.V.; Sakandelidze, R.M.; Sakhelashvili, T.M.; Chiladze, B.G.; Glonti, G.L.; Glonti, L.N.
2005-01-01
The SKLUST device has been created for gluing precision plane-parallel anode, cathode of spacer bars and integral anode and cathode frames of the MWPCs or flat surfaces of the large-area cathode planes for them in the case that thin copper clad stesalit or glass-cloth-base laminate is used as the cathode, for example, for the CSC chambers. In contrast to usual gluing, in this device the glued components are not pressed to each other. SKLUST allows making high-precision products in laboratory conditions without preliminarily machining its components and receiving a precision article practically for any area at the plane parallelism from ±0.030 up to ±0.006 mm using a non-calibrated sheet of the foiled (or unfoiled) stesalit, glass-cloth-base laminate or other flexible materials to a tolerance for the thickness ±0.2-0.5 mm or worse. On the biggest of the existing devices it is possible to fabricate an article with the maximal sizes 2400x250 mm 2 at the thickness accuracy (6±0.015) mm (maximum deviation). Whereas in the technological cycle machining of blanks to the thickness or application of exact blanks is completely excluded, the manufacturing process becomes simpler, and the price of the articles essentially reduces, especially for mass production
High precision innovative micropump for artificial pancreas
Chappel, E.; Mefti, S.; Lettieri, G.-L.; Proennecke, S.; Conan, C.
2014-03-01
The concept of artificial pancreas, which comprises an insulin pump, a continuous glucose meter and a control algorithm, is a major step forward in managing patient with type 1 diabetes mellitus. The stability of the control algorithm is based on short-term precision micropump to deliver rapid-acting insulin and to specific integrated sensors able to monitor any failure leading to a loss of accuracy. Debiotech's MEMS micropump, based on the membrane pump principle, is made of a stack of 3 silicon wafers. The pumping chamber comprises a pillar check-valve at the inlet, a pumping membrane which is actuated against stop limiters by a piezo cantilever, an anti-free-flow outlet valve and a pressure sensor. The micropump inlet is tightly connected to the insulin reservoir while the outlet is in direct communication with the patient skin via a cannula. To meet the requirement of a pump dedicated to closed-loop application for diabetes care, in addition to the well-controlled displacement of the pumping membrane, the high precision of the micropump is based on specific actuation profiles that balance effect of pump elasticity in low-consumption push-pull mode.
Closed-Loop Targeted Memory Reactivation during Sleep Improves Spatial Navigation
Directory of Open Access Journals (Sweden)
Renee E. Shimizu
2018-02-01
Full Text Available Sounds associated with newly learned information that are replayed during non-rapid eye movement (NREM sleep can improve recall in simple tasks. The mechanism for this improvement is presumed to be reactivation of the newly learned memory during sleep when consolidation takes place. We have developed an EEG-based closed-loop system to precisely deliver sensory stimulation at the time of down-state to up-state transitions during NREM sleep. Here, we demonstrate that applying this technology to participants performing a realistic navigation task in virtual reality results in a significant improvement in navigation efficiency after sleep that is accompanied by increases in the spectral power especially in the fast (12–15 Hz sleep spindle band. Our results show promise for the application of sleep-based interventions to drive improvement in real-world tasks.
High precision NC lathe feeding system rigid-flexible coupling model reduction technology
Xuan, He; Hua, Qingsong; Cheng, Lianjun; Zhang, Hongxin; Zhao, Qinghai; Mao, Xinkai
2017-08-01
This paper proposes the use of dynamic substructure method of reduction of order to achieve effective reduction of feed system for high precision NC lathe feeding system rigid-flexible coupling model, namely the use of ADAMS to establish the rigid flexible coupling simulation model of high precision NC lathe, and then the vibration simulation of the period by using the FD 3D damper is very effective for feed system of bolt connection reduction of multi degree of freedom model. The vibration simulation calculation is more accurate, more quickly.
High precision measurements of the luminosity at LEP
International Nuclear Information System (INIS)
Pietrzyk, B.
1994-01-01
The art of the luminosity measurements at LEP is presented. First generation LEP detectors have measured the absolute luminosity with the precision of 0.3-0.5%. The most precise present detectors have reached the 0.07% precision and the 0.05% is not excluded in future. Center-of-mass energy dependent relative precision of the luminosity detectors and the use of the theoretical cross-section in the LEP experiments are also discussed. (author). 18 refs., 6 figs., 6 tabs
Lee, Taehwa; Luo, Wei; Li, Qiaochu; Guo, L. Jay
2017-03-01
Laser-generated focused ultrasound has shown great promise in precisely treating cells and tissues by producing controlled micro-cavitation within the acoustic focal volume (30 MPa, negative pressure amplitude). By moving cavitation spots along pre-defined paths through a motorized stage, tissue-mimicking gels of different elastic moduli were cut into different shapes (rectangle, triangle, and circle), leaving behind the same shape of holes, whose sizes are less than 1 mm. The cut line width is estimated to be less than 50 um (corresponding to localized cavitation region), allowing for accurate cutting. This novel approach could open new possibility for in-vivo treatment of diseased tissues in a high-precision manner (i.e., high-precision invisible sonic scalpel).
Voirin, Thomas; Delaune, Jeff; Le Besnerais, Guy; Farges, Jean Loup; Bourdarias, Clément; Krüger, Hans
2013-01-01
After ExoMars in 2016 and 2018, future ESA missions to Mars, the Moon, or asteroids will require safe and pinpoint precision landing capabilities, with for example a specified accuracy of typically 100 m at touchdown for a Moon landing. The safe landing requirement can be met thanks to state-of-the-art Terrain-Relative Navigation (TRN) sensors such as Wide-Field-of-View vision-based navigation cameras (VBNC), with appropriate hazard detection and avoidance algorithms. To reach the pinpoint pr...
A projective surgical navigation system for cancer resection
Gan, Qi; Shao, Pengfei; Wang, Dong; Ye, Jian; Zhang, Zeshu; Wang, Xinrui; Xu, Ronald
2016-03-01
Near infrared (NIR) fluorescence imaging technique can provide precise and real-time information about tumor location during a cancer resection surgery. However, many intraoperative fluorescence imaging systems are based on wearable devices or stand-alone displays, leading to distraction of the surgeons and suboptimal outcome. To overcome these limitations, we design a projective fluorescence imaging system for surgical navigation. The system consists of a LED excitation light source, a monochromatic CCD camera, a host computer, a mini projector and a CMOS camera. A software program is written by C++ to call OpenCV functions for calibrating and correcting fluorescence images captured by the CCD camera upon excitation illumination of the LED source. The images are projected back to the surgical field by the mini projector. Imaging performance of this projective navigation system is characterized in a tumor simulating phantom. Image-guided surgical resection is demonstrated in an ex-vivo chicken tissue model. In all the experiments, the projected images by the projector match well with the locations of fluorescence emission. Our experimental results indicate that the proposed projective navigation system can be a powerful tool for pre-operative surgical planning, intraoperative surgical guidance, and postoperative assessment of surgical outcome. We have integrated the optoelectronic elements into a compact and miniaturized system in preparation for further clinical validation.
Design of a self-calibration high precision micro-angle deformation optical monitoring scheme
Gu, Yingying; Wang, Li; Guo, Shaogang; Wu, Yun; Liu, Da
2018-03-01
In order to meet the requirement of high precision and micro-angle measurement on orbit, a self-calibrated optical non-contact real-time monitoring device is designed. Within three meters, the micro-angle variable of target relative to measuring basis can be measured in real-time. The range of angle measurement is +/-50'', the angle measurement accuracy is less than 2''. The equipment can realize high precision real-time monitoring the micro-angle deformation, which caused by high strength vibration and shock of rock launching, sun radiation and heat conduction on orbit and so on.
High Precision Fast Projective Synchronization for Chaotic Systems with Unknown Parameters
Nian, Fuzhong; Wang, Xingyuan; Lin, Da; Niu, Yujun
2013-08-01
A high precision fast projective synchronization method for chaotic systems with unknown parameters was proposed by introducing optimal matrix. Numerical simulations indicate that the precision be improved about three orders compared with other common methods under the same condition of software and hardware. Moreover, when average error is less than 10-3, the synchronization speed is 6500 times than common methods, the iteration needs only 4 times. The unknown parameters also were identified rapidly. The theoretical analysis and proof also were given.
2012-07-20
... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Parts 84 and 115 [Docket No. USCG-2012-0306] RIN 1625-AB86 Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments...), the Coast Guard published a final rule entitled ``Navigation and Navigable Waters; Technical...
The 22nd Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting
International Nuclear Information System (INIS)
Sydnor, R.L.
1990-05-01
Papers presented at the 22nd Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting are compiled. The following subject areas are covered: Rb, Cs, and H-based frequency standards and cryogenic and trapped-ion technology; satellite laser tracking networks, GLONASS timing, intercomparison of national time scales and international telecommunications; telecommunications, power distribution, platform positioning, and geophysical survey industries; military communications and navigation systems; and dissemination of precise time and frequency by means of GPS, GLONASS, MIL STAR, LORAN, and synchronous communication satellites
Directory of Open Access Journals (Sweden)
Priya Bhattacharji
2017-01-01
Full Text Available Introduction. To evaluate the accuracy of a quantitative 3D navigation system for CT-guided interventional procedures in a two-part study. Materials and Methods. Twenty-two procedures were performed in abdominal and thoracic phantoms. Accuracies of the 3D anatomy map registration and navigation were evaluated. Time used for the navigated procedures was recorded. In the IRB approved clinical evaluation, 21 patients scheduled for CT-guided thoracic and hepatic biopsy and ablations were recruited. CT-guided procedures were performed without following the 3D navigation display. Accuracy of navigation as well as workflow fitness of the system was evaluated. Results. In phantoms, the average 3D anatomy map registration error was 1.79 mm. The average navigated needle placement accuracy for one-pass and two-pass procedures, respectively, was 2.0±0.7 mm and 2.8±1.1 mm in the liver and 2.7±1.7 mm and 3.0±1.4 mm in the lung. The average accuracy of the 3D navigation system in human subjects was 4.6 mm ± 3.1 for all procedures. The system fits the existing workflow of CT-guided interventions with minimum impact. Conclusion. A 3D navigation system can be performed along the existing workflow and has the potential to navigate precision needle placement in CT-guided interventional procedures.
High Precision Measurement of the differential W and Z boson cross-sections
Gasnikova, Ksenia; The ATLAS collaboration
2017-01-01
Measurements of the Drell-Yan production of W and Z/gamma bosons at the LHC provide a benchmark of our understanding of perturbative QCD and probe the proton structure in a unique way. The ATLAS collaboration has performed new high precision measurements at center-of-mass energies of 7. The measurements are performed for W+, W- and Z/gamma bosons integrated and as a function of the boson or lepton rapidity and the Z/gamma* mass. Unprecedented precision is reached and strong constraints on Parton Distribution functions, in particular the strange density are found. Z cross sections are also measured at a center-of-mass energies of 8TeV and 13TeV, and cross-section ratios to the top-quark pair production have been derived. This ratio measurement leads to a cancellation of several systematic effects and allows therefore for a high precision comparison to the theory predictions.
High precision analysis of trace lithium isotope by thermal ionization mass spectrometry
International Nuclear Information System (INIS)
Tang Lei; Liu Xuemei; Long Kaiming; Liu Zhao; Yang Tianli
2010-01-01
High precision analysis method of ng lithium by thermal ionization mass spectrometry is developed. By double-filament measurement,phosphine acid ion enhancer and sample pre-baking technique,the precision of trace lithium analysis is improved. For 100 ng lithium isotope standard sample, relative standard deviation is better than 0.086%; for 10 ng lithium isotope standard sample, relative standard deviation is better than 0.90%. (authors)
High spatial precision nano-imaging of polarization-sensitive plasmonic particles
Liu, Yunbo; Wang, Yipei; Lee, Somin Eunice
2018-02-01
Precise polarimetric imaging of polarization-sensitive nanoparticles is essential for resolving their accurate spatial positions beyond the diffraction limit. However, conventional technologies currently suffer from beam deviation errors which cannot be corrected beyond the diffraction limit. To overcome this issue, we experimentally demonstrate a spatially stable nano-imaging system for polarization-sensitive nanoparticles. In this study, we show that by integrating a voltage-tunable imaging variable polarizer with optical microscopy, we are able to suppress beam deviation errors. We expect that this nano-imaging system should allow for acquisition of accurate positional and polarization information from individual nanoparticles in applications where real-time, high precision spatial information is required.
Paziewski, Jacek; Sieradzki, Rafal; Baryla, Radoslaw
2018-03-01
This paper provides the methodology and performance assessment of multi-GNSS signal processing for the detection of small-scale high-rate dynamic displacements. For this purpose, we used methods of relative (RTK) and absolute positioning (PPP), and a novel direct signal processing approach. The first two methods are recognized as providing accurate information on position in many navigation and surveying applications. The latter is an innovative method for dynamic displacement determination with the use of GNSS phase signal processing. This method is based on the developed functional model with parametrized epoch-wise topocentric relative coordinates derived from filtered GNSS observations. Current regular kinematic PPP positioning, as well as medium/long range RTK, may not offer coordinate estimates with subcentimeter precision. Thus, extended processing strategies of absolute and relative GNSS positioning have been developed and applied for displacement detection. The study also aimed to comparatively analyze the developed methods as well as to analyze the impact of combined GPS and BDS processing and the dependence of the results of the relative methods on the baseline length. All the methods were implemented with in-house developed software allowing for high-rate precise GNSS positioning and signal processing. The phase and pseudorange observations collected with a rate of 50 Hz during the field test served as the experiment’s data set. The displacements at the rover station were triggered in the horizontal plane using a device which was designed and constructed to ensure a periodic motion of GNSS antenna with an amplitude of ~3 cm and a frequency of ~4.5 Hz. Finally, a medium range RTK, PPP, and direct phase observation processing method demonstrated the capability of providing reliable and consistent results with the precision of the determined dynamic displacements at the millimeter level. Specifically, the research shows that the standard deviation of
Precise muon drift tube detectors for high background rate conditions
Engl, Albert; Dünnweber, Wolfgang
The muon spectrometer of the ATLAS-experiment at the Large H adron Collider consists of drift tube chambers, which provide the precise m easurement of trajec- tories of traversing muons. In order to determine the moment um of the muons with high precision, the measurement of the position of the m uon in a single tube has to be more accurate than σ ≤ 100 m. The large cross section of proton-proton-collisions and th e high luminosity of the accelerator cause relevant background of neutrons and γ s in the muon spectrome- ter. During the next decade a luminosity upgrade [1] to 5 10 34 cm − 2 s − 1 is planned, which will increase the background counting rates consider ably. In this context this work deals with the further development of the existing drift chamber tech- nology to provide the required accuracy of the position meas urement under high background conditions. Two approaches of improving the dri ft tube chambers are described: • In regions of moderate background rates a faster and more lin ear ...
Radar and electronic navigation
Sonnenberg, G J
2013-01-01
Radar and Electronic Navigation, Sixth Edition discusses radar in marine navigation, underwater navigational aids, direction finding, the Decca navigator system, and the Omega system. The book also describes the Loran system for position fixing, the navy navigation satellite system, and the global positioning system (GPS). It reviews the principles, operation, presentations, specifications, and uses of radar. It also describes GPS, a real time position-fixing system in three dimensions (longitude, latitude, altitude), plus velocity information with Universal Time Coordinated (UTC). It is accur
Data Analysis of the TK-1G Sounding Rocket Installed with a Satellite Navigation System
Directory of Open Access Journals (Sweden)
Lesong Zhou
2017-10-01
Full Text Available This article gives an in-depth analysis of the experimental data of the TK-1G sounding rocket installed with the satellite navigation system. It turns out that the data acquisition rate of the rocket sonde is high, making the collection of complete trajectory and meteorological data possible. By comparing the rocket sonde measurements with those obtained by virtue of other methods, we find that the rocket sonde can be relatively precise in measuring atmospheric parameters within the scope of 20–60 km above the ground. This establishes the fact that the TK-1G sounding rocket system is effective in detecting near-space atmospheric environment.
High precision straw tube chamber with cathode readout
International Nuclear Information System (INIS)
Bychkov, V.N.; Golutvin, I.A.; Ershov, Yu.V.
1992-01-01
The high precision straw chamber with cathode readout was constructed and investigated. The 10 mm straws were made of aluminized mylar strip with transparent longitudinal window. The X coordinate information has been taken from the cathode strips as induced charges and investigated via centroid method. The spatial resolution σ=120 μm has been obtained with signal/noise ratio about 60. The possible ways for improving the signal/noise ratio have been described. 7 refs.; 8 figs
International Nuclear Information System (INIS)
Bradshaw, R.C.; Schmidt, D.P.; Rogers, J.R.; Kelton, K.F.; Hyers, R.W.
2005-01-01
By combining the best practices in optical dilatometry with numerical methods, a high-speed and high-precision technique has been developed to measure the volume of levitated, containerlessly processed samples with subpixel resolution. Containerless processing provides the ability to study highly reactive materials without the possibility of contamination affecting thermophysical properties. Levitation is a common technique used to isolate a sample as it is being processed. Noncontact optical measurement of thermophysical properties is very important as traditional measuring methods cannot be used. Modern, digitally recorded images require advanced numerical routines to recover the subpixel locations of sample edges and, in turn, produce high-precision measurements
Navigating nuclear science: Enhancing analysis through visualization
Energy Technology Data Exchange (ETDEWEB)
Irwin, N.H.; Berkel, J. van; Johnson, D.K.; Wylie, B.N.
1997-09-01
Data visualization is an emerging technology with high potential for addressing the information overload problem. This project extends the data visualization work of the Navigating Science project by coupling it with more traditional information retrieval methods. A citation-derived landscape was augmented with documents using a text-based similarity measure to show viability of extension into datasets where citation lists do not exist. Landscapes, showing hills where clusters of similar documents occur, can be navigated, manipulated and queried in this environment. The capabilities of this tool provide users with an intuitive explore-by-navigation method not currently available in today`s retrieval systems.
High-precision multiband spectroscopy of ultracold fermions in a nonseparable optical lattice
Fläschner, Nick; Tarnowski, Matthias; Rem, Benno S.; Vogel, Dominik; Sengstock, Klaus; Weitenberg, Christof
2018-05-01
Spectroscopic tools are fundamental for the understanding of complex quantum systems. Here, we demonstrate high-precision multiband spectroscopy in a graphenelike lattice using ultracold fermionic atoms. From the measured band structure, we characterize the underlying lattice potential with a relative error of 1.2 ×10-3 . Such a precise characterization of complex lattice potentials is an important step towards precision measurements of quantum many-body systems. Furthermore, we explain the excitation strengths into different bands with a model and experimentally study their dependency on the symmetry of the perturbation operator. This insight suggests the excitation strengths as a suitable observable for interaction effects on the eigenstates.
Active-passive hybrid piezoelectric actuators for high-precision hard disk drive servo systems
Chan, Kwong Wah; Liao, Wei-Hsin
2006-03-01
Positioning precision is crucial to today's increasingly high-speed, high-capacity, high data density, and miniaturized hard disk drives (HDDs). The demand for higher bandwidth servo systems that can quickly and precisely position the read/write head on a high track density becomes more pressing. Recently, the idea of applying dual-stage actuators to track servo systems has been studied. The push-pull piezoelectric actuated devices have been developed as micro actuators for fine and fast positioning, while the voice coil motor functions as a large but coarse seeking. However, the current dual-stage actuator design uses piezoelectric patches only without passive damping. In this paper, we propose a dual-stage servo system using enhanced active-passive hybrid piezoelectric actuators. The proposed actuators will improve the existing dual-stage actuators for higher precision and shock resistance, due to the incorporation of passive damping in the design. We aim to develop this hybrid servo system not only to increase speed of track seeking but also to improve precision of track following servos in HDDs. New piezoelectrically actuated suspensions with passive damping have been designed and fabricated. In order to evaluate positioning and track following performances for the dual-stage track servo systems, experimental efforts are carried out to implement the synthesized active-passive suspension structure with enhanced piezoelectric actuators using a composite nonlinear feedback controller.
Vision Based Autonomous Robot Navigation Algorithms and Implementations
Chatterjee, Amitava; Nirmal Singh, N
2013-01-01
This book is devoted to the theory and development of autonomous navigation of mobile robots using computer vision based sensing mechanism. The conventional robot navigation systems, utilizing traditional sensors like ultrasonic, IR, GPS, laser sensors etc., suffer several drawbacks related to either the physical limitations of the sensor or incur high cost. Vision sensing has emerged as a popular alternative where cameras can be used to reduce the overall cost, maintaining high degree of intelligence, flexibility and robustness. This book includes a detailed description of several new approaches for real life vision based autonomous navigation algorithms and SLAM. It presents the concept of how subgoal based goal-driven navigation can be carried out using vision sensing. The development concept of vision based robots for path/line tracking using fuzzy logic is presented, as well as how a low-cost robot can be indigenously developed in the laboratory with microcontroller based sensor systems. The book descri...
Precision laser spectroscopy of highly charged ions
International Nuclear Information System (INIS)
Kuehl, T.; Borneis, S.; Becker, S.; Dax, A.; Engel, T.; Grieser, R.; Huber, G.; Klaft, I.; Klepper, O.; Kohl, A.; Marx, D.; Meier, K.; Neumann, R.; Schmitt, F.; Seelig, P.; Voelker, L.
1996-01-01
Recently, intense beams of highly charged ions have become available at heavy ion cooler rings. The obstacle for producing these highly interesting candidates is the large binding energy of K-shell electrons in heavy systems in excess of 100 keV. One way to remove these electrons is to strip them off by passing the ion through material. In the cooler ring, the ions are cooled to a well defined velocity. At the SIS/ESR complex it is possible to produce, store, and cool highly charged ions up to bare uranium with intensities exceeding 10 8 atoms in the ring. This opens the door for precision laser spectroscopy of hydrogenlike-heavy ions, e.g. 209 Bi 82+ , and allows to examine the interaction of the single electron with the large fields of the heavy nucleus, exceeding any artificially produced electric and magnetic fields by orders of magnitude. In the electron cooler the interaction of electrons and highly charged ions otherwise only present in the hottest plasmas can be studied. (orig.)
Štefanička, Tomáš; Ďuračiová, Renata; Seres, Csaba
2017-12-01
As a complex of buildings, the Faculty of Natural Sciences of the Comenius University in Bratislava tends to be difficult to navigate in spite of its size. An indoor navigation application could potentially save a lot of time and frustration. There are currently numerous technologies used in indoor navigation systems. Some of them focus on a high degree of precision and require significant financial investment; others provide only static information about a current location. In this paper we focused on the determination of an approximate location using inertial measurement systems available on most smartphones, i.e., a gyroscope and an accelerometer. The actual position of the device was calculated using "a walk detection method" based on a delayed lack of motion. We have developed an indoor navigation application that relies solely on open source JavaScript libraries to visualize the interior of the building and calculate the shortest path utilizing Dijsktra's routing algorithm. The application logic is located on the client side, so the software is able to work offline. Our solution represents an accessible lowcost and platform-independent web application that can significantly improve navigation at the Faculty of Natural Sciences. Although our application has been developed on a specific building complex, it could be used in other interiors as well.
Ultracold Anions for High-Precision Antihydrogen Experiments.
Cerchiari, G; Kellerbauer, A; Safronova, M S; Safronova, U I; Yzombard, P
2018-03-30
Experiments with antihydrogen (H[over ¯]) for a study of matter-antimatter symmetry and antimatter gravity require ultracold H[over ¯] to reach ultimate precision. A promising path towards antiatoms much colder than a few kelvin involves the precooling of antiprotons by laser-cooled anions. Because of the weak binding of the valence electron in anions-dominated by polarization and correlation effects-only few candidate systems with suitable transitions exist. We report on a combination of experimental and theoretical studies to fully determine the relevant binding energies, transition rates, and branching ratios of the most promising candidate La^{-}. Using combined transverse and collinear laser spectroscopy, we determined the resonant frequency of the laser cooling transition to be ν=96.592 713(91) THz and its transition rate to be A=4.90(50)×10^{4} s^{-1}. Using a novel high-precision theoretical treatment of La^{-} we calculated yet unmeasured energy levels, transition rates, branching ratios, and lifetimes to complement experimental information on the laser cooling cycle of La^{-}. The new data establish the suitability of La^{-} for laser cooling and show that the cooling transition is significantly stronger than suggested by a previous theoretical study.
Context-Aided Sensor Fusion for Enhanced Urban Navigation
Directory of Open Access Journals (Sweden)
Enrique David Martí
2012-12-01
Full Text Available The deployment of Intelligent Vehicles in urban environments requires reliable estimation of positioning for urban navigation. The inherent complexity of this kind of environments fosters the development of novel systems which should provide reliable and precise solutions to the vehicle. This article details an advanced GNSS/IMU fusion system based on a context-aided Unscented Kalman filter for navigation in urban conditions. The constrained non-linear filter is here conditioned by a contextual knowledge module which reasons about sensor quality and driving context in order to adapt it to the situation, while at the same time it carries out a continuous estimation and correction of INS drift errors. An exhaustive analysis has been carried out with available data in order to characterize the behavior of available sensors and take it into account in the developed solution. The performance is then analyzed with an extensive dataset containing representative situations. The proposed solution suits the use of fusion algorithms for deploying Intelligent Transport Systems in urban environments.
A near infrared laser frequency comb for high precision Doppler planet surveys
Directory of Open Access Journals (Sweden)
Bally J.
2011-07-01
Full Text Available Perhaps the most exciting area of astronomical research today is the study of exoplanets and exoplanetary systems, engaging the imagination not just of the astronomical community, but of the general population. Astronomical instrumentation has matured to the level where it is possible to detect terrestrial planets orbiting distant stars via radial velocity (RV measurements, with the most stable visible light spectrographs reporting RV results the order of 1 m/s. This, however, is an order of magnitude away from the precision needed to detect an Earth analog orbiting a star such as our sun, the Holy Grail of these efforts. By performing these observations in near infrared (NIR there is the potential to simplify the search for distant terrestrial planets by studying cooler, less massive, much more numerous class M stars, with a tighter habitable zone and correspondingly larger RV signal. This NIR advantage is undone by the lack of a suitable high precision, high stability wavelength standard, limiting NIR RV measurements to tens or hundreds of m/s [1, 2]. With the improved spectroscopic precision provided by a laser frequency comb based wavelength reference producing a set of bright, densely and uniformly spaced lines, it will be possible to achieve up to two orders of magnitude improvement in RV precision, limited only by the precision and sensitivity of existing spectrographs, enabling the observation of Earth analogs through RV measurements. We discuss the laser frequency comb as an astronomical wavelength reference, and describe progress towards a near infrared laser frequency comb at the National Institute of Standards and Technology and at the University of Colorado where we are operating a laser frequency comb suitable for use with a high resolution H band astronomical spectrograph.
High precision and stable structures for particle detectors
Da Mota Silva, S; Hauviller, Claude
1999-01-01
The central detectors used in High Energy Physics Experiments require the use of light and stable structures capable of supporting delicate and precise radiation detection elements. These structures need to be highly stable under environmental conditions where external vibrations, high radiation levels, temperature and humidity gradients should be taken into account. Their main design drivers are high dimension and dynamic stability, high stiffness to mass ratio and large radiation length. For most applications, these constraints lead us to choose Carbon Fiber Reinforced Plastics ( CFRP) as structural element. The construction of light and stable structures with CFRP for these applications can be achieved by careful design engineering and further confirmation at the prototyping phase. However, the experimental environment can influence their characteristics and behavior. In this case, theuse of adaptive structures could become a solution for this problem. We are studying structures in CFRP with bonded piezoel...
Dynamics of High-Speed Precision Geared Rotor Systems
Directory of Open Access Journals (Sweden)
Lim Teik C.
2014-07-01
Full Text Available Gears are one of the most widely applied precision machine elements in power transmission systems employed in automotive, aerospace, marine, rail and industrial applications because of their reliability, precision, efficiency and versatility. Fundamentally, gears provide a very practical mechanism to transmit motion and mechanical power between two rotating shafts. However, their performance and accuracy are often hampered by tooth failure, vibrations and whine noise. This is most acute in high-speed, high power density geared rotor systems, which is the primary scope of this paper. The present study focuses on the development of a gear pair mathematical model for use to analyze the dynamics of power transmission systems. The theory includes the gear mesh representation derived from results of the quasi-static tooth contact analysis. This proposed gear mesh theory comprising of transmission error, mesh point, mesh stiffness and line-of-action nonlinear, time-varying parameters can be easily incorporated into a variety of transmission system models ranging from the lumped parameter type to detailed finite element representation. The gear dynamic analysis performed led to the discovery of the out-of-phase gear pair torsion modes that are responsible for much of the mechanical problems seen in gearing applications. The paper concludes with a discussion on effectual design approaches to minimize the influence of gear dynamics and to mitigate gear failure in practical power transmission systems.
OSIRIS-REx Flight Dynamics and Navigation Design
Williams, B.; Antreasian, P.; Carranza, E.; Jackman, C.; Leonard, J.; Nelson, D.; Page, B.; Stanbridge, D.; Wibben, D.; Williams, K.; Moreau, M.; Berry, K.; Getzandanner, K.; Liounis, A.; Mashiku, A.; Highsmith, D.; Sutter, B.; Lauretta, D. S.
2018-06-01
OSIRIS-REx is the first NASA mission to return a sample of an asteroid to Earth. Navigation and flight dynamics for the mission to acquire and return a sample of asteroid 101955 Bennu establish many firsts for space exploration. These include relatively small orbital maneuvers that are precise to ˜1 mm/s, close-up operations in a captured orbit about an asteroid that is small in size and mass, and planning and orbit phasing to revisit the same spot on Bennu in similar lighting conditions. After preliminary surveys and close approach flyovers of Bennu, the sample site will be scientifically characterized and selected. A robotic shock-absorbing arm with an attached sample collection head mounted on the main spacecraft bus acquires the sample, requiring navigation to Bennu's surface. A touch-and-go sample acquisition maneuver will result in the retrieval of at least 60 grams of regolith, and up to several kilograms. The flight activity concludes with a return cruise to Earth and delivery of the sample return capsule (SRC) for landing and sample recovery at the Utah Test and Training Range (UTTR).
An Effective Terrain Aided Navigation for Low-Cost Autonomous Underwater Vehicles.
Zhou, Ling; Cheng, Xianghong; Zhu, Yixian; Dai, Chenxi; Fu, Jinbo
2017-03-25
Terrain-aided navigation is a potentially powerful solution for obtaining submerged position fixes for autonomous underwater vehicles. The application of terrain-aided navigation with high-accuracy inertial navigation systems has demonstrated meter-level navigation accuracy in sea trials. However, available sensors may be limited depending on the type of the mission. Such limitations, especially for low-grade navigation sensors, not only degrade the accuracy of traditional navigation systems, but further impact the ability to successfully employ terrain-aided navigation. To address this problem, a tightly-coupled navigation is presented to successfully estimate the critical sensor errors by incorporating raw sensor data directly into an augmented navigation system. Furthermore, three-dimensional distance errors are calculated, providing measurement updates through the particle filter for absolute and bounded position error. The development of the terrain aided navigation system is elaborated for a vehicle equipped with a non-inertial-grade strapdown inertial navigation system, a 4-beam Doppler Velocity Log range sensor and a sonar altimeter. Using experimental data for navigation performance evaluation in areas with different terrain characteristics, the experiment results further show that the proposed method can be successfully applied to the low-cost AUVs and significantly improves navigation performance.
Super high precision 200 ppi liquid crystal display series; Chokoseido 200 ppi ekisho display series
Energy Technology Data Exchange (ETDEWEB)
NONE
2000-03-01
In mobile equipment, in demand is a high precision liquid crystal display (LCD) having the power of expression equivalent to printed materials like magazines because of the necessity of displaying a large amount of information on a easily potable small screen. In addition, with the spread and high-quality image of digital still cameras, it is strongly desired to display photographed digital image data in high quality. Toshiba Corp., by low temperature polysilicone (p-Si) technology, commercialized the liquid crystal display series of 200 ppi (pixels per inch) precision dealing with the rise of the high-precision high-image quality LCD market. The super high precision of 200 ppi enables the display of smooth beautiful animation comparable to printed sheets of magazines and photographs. The display series are suitable for the display of various information services such as electronic books and electronic photo-viewers including internet. The screen sizes lined up are No. 4 type VGA (640x480 pixels) of a small pocket notebook size and No. 6.3 type XGA (1,024x768 pixels) of a paperback size, with a larger screen to be furthered. (translated by NEDO)
An Ultra-low Frequency Modal Testing Suspension System for High Precision Air Pressure Control
Directory of Open Access Journals (Sweden)
Qiaoling YUAN
2014-05-01
Full Text Available As a resolution for air pressure control challenges in ultra-low frequency modal testing suspension systems, an incremental PID control algorithm with dead band is applied to achieve high-precision pressure control. We also develop a set of independent hardware and software systems for high-precision pressure control solutions. Taking control system versatility, scalability, reliability, and other aspects into considerations, a two-level communication employing Ethernet and CAN bus, is adopted to complete such tasks as data exchange between the IPC, the main board and the control board ,and the pressure control. Furthermore, we build a single set of ultra-low frequency modal testing suspension system and complete pressure control experiments, which achieve the desired results and thus confirm that the high-precision pressure control subsystem is reasonable and reliable.
Concept of modular flexure-based mechanisms for ultra-high precision robot design
Directory of Open Access Journals (Sweden)
M. Richard
2011-05-01
Full Text Available This paper introduces a new concept of modular flexure-based mechanisms to design industrial ultra-high precision robots, which aims at significantly reducing both the complexity of their design and their development time. This modular concept can be considered as a robotic Lego, where a finite number of building bricks is used to quickly build a high-precision robot. The core of the concept is the transformation of a 3-D design problem into several 2-D ones, which are simpler and well-mastered. This paper will first briefly present the theoretical bases of this methodology and the requirements of both types of building bricks: the active and the passive bricks. The section dedicated to the design of the active bricks will detail the current research directions, mainly the maximisation of the strokes and the development of an actuation sub-brick. As for the passive bricks, some examples will be presented, and a discussion regarding the establishment of a mechanical solution catalogue will conclude the section. Last, this modular concept will be illustrated with a practical example, consisting in the design of a 5-degree of freedom ultra-high precision robot.
IPS – A SYSTEM FOR REAL-TIME NAVIGATION AND 3D MODELING
Directory of Open Access Journals (Sweden)
D. Grießbach
2012-07-01
Full Text Available fdaReliable navigation and 3D modeling is a necessary requirement for any autonomous system in real world scenarios. German Aerospace Center (DLR developed a system providing precise information about local position and orientation of a mobile platform as well as three-dimensional information about its environment in real-time. This system, called Integral Positioning System (IPS can be applied for indoor environments and outdoor environments. To achieve high precision, reliability, integrity and availability a multi-sensor approach was chosen. The important role of sensor data synchronization, system calibration and spatial referencing is emphasized because the data from several sensors has to be fused using a Kalman filter. A hardware operating system (HW-OS is presented, that facilitates the low-level integration of different interfaces. The benefit of this approach is an increased precision of synchronization at the expense of additional engineering costs. It will be shown that the additional effort is leveraged by the new design concept since the HW-OS methodology allows a proven, flexible and fast design process, a high re-usability of common components and consequently a higher reliability within the low-level sensor fusion. Another main focus of the paper is on IPS software. The DLR developed, implemented and tested a flexible and extensible software concept for data grabbing, efficient data handling, data preprocessing (e.g. image rectification being essential for thematic data processing. Standard outputs of IPS are a trajectory of the moving platform and a high density 3D point cloud of the current environment. This information is provided in real-time. Based on these results, information processing on more abstract levels can be executed.
Electromagnetic Charge Radius of the Pion at High Precision
Ananthanarayan, B.; Caprini, Irinel; Das, Diganta
2017-09-01
We present a determination of the pion charge radius from high precision data on the pion vector form factor from both timelike and spacelike regions, using a novel formalism based on analyticity and unitarity. At low energies, instead of the poorly known modulus of the form factor, we use its phase, known with high accuracy from Roy equations for π π elastic scattering via the Fermi-Watson theorem. We use also the values of the modulus at several higher timelike energies, where the data from e+e- annihilation and τ decay are mutually consistent, as well as the most recent measurements at spacelike momenta. The experimental uncertainties are implemented by Monte Carlo simulations. The results, which do not rely on a specific parametrization, are optimal for the given input information and do not depend on the unknown phase of the form factor above the first inelastic threshold. Our prediction for the charge radius of the pion is rπ=(0.657 ±0.003 ) fm , which amounts to an increase in precision by a factor of about 2.7 compared to the Particle Data Group average.
Strategies for high-precision Global Positioning System orbit determination
Lichten, Stephen M.; Border, James S.
1987-01-01
Various strategies for the high-precision orbit determination of the GPS satellites are explored using data from the 1985 GPS field test. Several refinements to the orbit determination strategies were found to be crucial for achieving high levels of repeatability and accuracy. These include the fine tuning of the GPS solar radiation coefficients and the ground station zenith tropospheric delays. Multiday arcs of 3-6 days provided better orbits and baselines than the 8-hr arcs from single-day passes. Highest-quality orbits and baselines were obtained with combined carrier phase and pseudorange solutions.
Advancing theranostics with tumor-targeting peptides for precision otolaryngology
Directory of Open Access Journals (Sweden)
Chadwick L. Wright
2016-06-01
Full Text Available Worldwide, about 600,000 head and neck squamous cell carcinoma (HNSCC are detected annually, many of which involve high risk human papilloma virus (HPV. Surgery is the primary and desired first treatment option. Following surgery, the existence of cancer cells at the surgical margin is strongly associated with eventual recurrence of cancer and a poor outcome. Despite improved surgical methods (robotics, microsurgery, endoscopic/laparoscopic, and external imaging, surgeons rely only on their vision and touch to locate tumors during surgery. Diagnostic imaging systems like computed tomography (CT, magnetic resonance imaging (MRI, single-photon emission computed tomography (SPECT and positron-emission tomography (PET are too large, slow and costly to use efficiently during most surgeries and, ultrasound imaging, while fast and portable, is not cancer specific. This purpose of this article is to review the fundamental technologies that will radically advance Precision Otolaryngology practices to the benefit of patients with HNSCC. In particular, this article will address the potential for tumor-targeting peptides to enable more precise diagnostic imaging while simultaneously advancing new therapeutic paradigms for next generation image-guided surgery, tumor-specific chemotherapeutic delivery and tumor-selective targeted radiotherapy (i.e., theranostic. Keywords: Squamous cell carcinoma, Peptide, Optical surgical navigation, Diagnostic imaging, Theranostic
Pines, S.
1982-01-01
The problems in navigation and guidance encountered by aircraft in the initial transition period in changing from distance measuring equipment, VORTAC, and barometric instruments to the more precise microwave landing system data type navaids in the terminal area are investigated. The effects of the resulting discontinuities on the estimates of position and velocity for both optimal (Kalman type navigation schemes) and fixed gain (complementary type) navigation filters, and the effects of the errors in cross track, track angle, and altitude on the guidance equation and control commands during the critical landing phase are discussed. A method is presented to remove the discontinuities from the navigation loop and to reconstruct an RNAV path designed to land the aircraft with minimal turns and altitude changes.
Cui, Licong; Xu, Rong; Luo, Zhihui; Wentz, Susan; Scarberry, Kyle; Zhang, Guo-Qiang
2014-08-03
Finding quality consumer health information online can effectively bring important public health benefits to the general population. It can empower people with timely and current knowledge for managing their health and promoting wellbeing. Despite a popular belief that search engines such as Google can solve all information access problems, recent studies show that using search engines and simple search terms is not sufficient. Our objective is to provide an approach to organizing consumer health information for navigational exploration, complementing keyword-based direct search. Multi-topic assignment to health information, such as online questions, is a fundamental step for navigational exploration. We introduce a new multi-topic assignment method combining semantic annotation using UMLS concepts (CUIs) and Formal Concept Analysis (FCA). Each question was tagged with CUIs identified by MetaMap. The CUIs were filtered with term-frequency and a new term-strength index to construct a CUI-question context. The CUI-question context and a topic-subject context were used for multi-topic assignment, resulting in a topic-question context. The topic-question context was then directly used for constructing a prototype navigational exploration interface. Experimental evaluation was performed on the task of automatic multi-topic assignment of 99 predefined topics for about 60,000 consumer health questions from NetWellness. Using example-based metrics, suitable for multi-topic assignment problems, our method achieved a precision of 0.849, recall of 0.774, and F₁ measure of 0.782, using a reference standard of 278 questions with manually assigned topics. Compared to NetWellness' original topic assignment, a 36.5% increase in recall is achieved with virtually no sacrifice in precision. Enhancing the recall of multi-topic assignment without sacrificing precision is a prerequisite for achieving the benefits of navigational exploration. Our new multi-topic assignment method
33 CFR 66.05-100 - Designation of navigable waters as State waters for private aids to navigation.
2010-07-01
... as State waters for private aids to navigation. 66.05-100 Section 66.05-100 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION PRIVATE AIDS TO NAVIGATION State Aids to Navigation § 66.05-100 Designation of navigable waters as State waters for private aids to...
Fabrication of high precision metallic freeform mirrors with magnetorheological finishing (MRF)
Beier, Matthias; Scheiding, Sebastian; Gebhardt, Andreas; Loose, Roman; Risse, Stefan; Eberhardt, Ramona; Tünnermann, Andreas
2013-09-01
The fabrication of complex shaped metal mirrors for optical imaging is a classical application area of diamond machining techniques. Aspherical and freeform shaped optical components up to several 100 mm in diameter can be manufactured with high precision in an acceptable amount of time. However, applications are naturally limited to the infrared spectral region due to scatter losses for shorter wavelengths as a result of the remaining periodic diamond turning structure. Achieving diffraction limited performance in the visible spectrum demands for the application of additional polishing steps. Magnetorheological Finishing (MRF) is a powerful tool to improve figure and finish of complex shaped optics at the same time in a single processing step. The application of MRF as a figuring tool for precise metal mirrors is a nontrivial task since the technology was primarily developed for figuring and finishing a variety of other optical materials, such as glasses or glass ceramics. In the presented work, MRF is used as a figuring tool for diamond turned aluminum lightweight mirrors with electroless nickel plating. It is applied as a direct follow-up process after diamond machining of the mirrors. A high precision measurement setup, composed of an interferometer and an advanced Computer Generated Hologram with additional alignment features, allows for precise metrology of the freeform shaped optics in short measuring cycles. Shape deviations less than 150 nm PV / 20 nm rms are achieved reliably for freeform mirrors with apertures of more than 300 mm. Characterization of removable and induced spatial frequencies is carried out by investigating the Power Spectral Density.
Investigation of the proton-neutron interaction by high-precision nuclear mass measurements
Savreux, R P; Akkus, B
2007-01-01
We propose to measure the atomic masses of a series of short-lived nuclides, including $^{70}$Ni, $^{122-130}$Cd, $^{134}$Sn, $^{138,140}$Xe, $^{207-210}$Hg, and $^{223-225}$Rn, that contribute to the investigation of the proton-neutron interaction and its role in nuclear structure. The high-precision mass measurements are planned for the Penning trap mass spectrometer ISOLTRAP that reaches the required precision of 10 keV in the nuclear mass determination.
Generation of High-Resolution Geo-referenced Photo-Mosaics From Navigation Data
Delaunoy, O.; Elibol, A.; Garcia, R.; Escartin, J.; Fornari, D.; Humphris, S.
2006-12-01
Optical images of the ocean floor are a rich source of data to understand biological and geological processes. However, due to the attenuation of light in sea water, the area covered by the optical systems is very reduced, and a large number of images are then needed in order to cover an area of interest, as individually they do not provide a global view of the surveyed area. Therefore, generating a composite view (or photo-mosaic) from multiple overlapping images is usually the most practical and flexible solution to visually cover a wide area, allowing the analysis of the site in one single representation of the ocean floor. In most of the camera surveys which are carried out nowadays, some sort of positioning information is available (e.g., USBL, DVL, INS, gyros, etc). If it is a towed camera an estimation of the length of the tether and the mother ship GPS reading could also serve as navigation data. In any case, a photo-mosaic can be build just by taking into account the position and orientation of the camera. On the other hand, most of the regions of interest for the scientific community are quite large (>1Km2) and since better resolution is always required, the final photo-mosaic can be very large (>1,000,000 × 1,000,000 pixels), and cannot be handled by commonly available software. For this reason, we have developed a software package able to load a navigation file and the sequence of acquired images to automatically build a geo-referenced mosaic. This navigated mosaic provides a global view of the interest site, at the maximum available resolution. The developed package includes a viewer, allowing the user to load, view and annotate these geo-referenced photo-mosaics on a personal computer. A software library has been developed to allow the viewer to manage such very big images. Therefore, the size of the resulting mosaic is now only limited by the size of the hard drive. Work is being carried out to apply image processing techniques to the navigated
Navigation and Image Injection for Control of Bone Removal and Osteotomy Planes in Spine Surgery.
Kosterhon, Michael; Gutenberg, Angelika; Kantelhardt, Sven Rainer; Archavlis, Elefterios; Giese, Alf
2017-04-01
In contrast to cranial interventions, neuronavigation in spinal surgery is used in few applications, not tapping into its full technological potential. We have developed a method to preoperatively create virtual resection planes and volumes for spinal osteotomies and export 3-D operation plans to a navigation system controlling intraoperative visualization using a surgical microscope's head-up display. The method was developed using a Sawbone ® model of the lumbar spine, demonstrating feasibility with high precision. Computer tomographic and magnetic resonance image data were imported into Amira ® , a 3-D visualization software. Resection planes were positioned, and resection volumes representing intraoperative bone removal were defined. Fused to the original Digital Imaging and Communications in Medicine data, the osteotomy planes were exported to the cranial version of a Brainlab ® navigation system. A navigated surgical microscope with video connection to the navigation system allowed intraoperative image injection to visualize the preplanned resection planes. The workflow was applied to a patient presenting with a congenital hemivertebra of the thoracolumbar spine. Dorsal instrumentation with pedicle screws and rods was followed by resection of the deformed vertebra guided by the in-view image injection of the preplanned resection planes into the optical path of a surgical microscope. Postoperatively, the patient showed no neurological deficits, and the spine was found to be restored in near physiological posture. The intraoperative visualization of resection planes in a microscope's head-up display was found to assist the surgeon during the resection of a complex-shaped bone wedge and may help to further increase accuracy and patient safety. Copyright © 2017 by the Congress of Neurological Surgeons
Navigation Problems in Blind-to-Blind Pedestrians Tele-assistance Navigation
Balata , Jan; Mikovec , Zdenek; Maly , Ivo
2015-01-01
International audience; We raise a question whether it is possible to build a large-scale navigation system for blind pedestrians where a blind person navigates another blind person remotely by mobile phone. We have conducted an experiment, in which we observed blind people navigating each other in a city center in 19 sessions. We focused on problems in the navigator’s attempts to direct the traveler to the destination. We observed 96 problems in total, classified them on the basis of the typ...
A navigator-based rigid body motion correction for magnetic resonance imaging
International Nuclear Information System (INIS)
Ullisch, Marcus Goerge
2012-01-01
A novel three-dimensional navigator k-space trajectory for rigid body motion detection for Magnetic Resonance Imaging (MRI) - the Lissajous navigator - was developed and quantitatively compared to the existing spherical navigator trajectory [1]. The spherical navigator cannot sample the complete spherical surface due to slew rate limitations of the scanner hardware. By utilizing a two dimensional Lissajous figure which is projected onto the spherical surface, the Lissajous navigator overcomes this limitation. The complete sampling of the sphere consequently leads to rotation estimates with higher and more isotropic accuracy. Simulations and phantom measurements were performed for both navigators. Both simulations and measurements show a significantly higher overall accuracy of the Lissajous navigator and a higher isotropy of the rotation estimates. Measured under identical conditions with identical postprocessing, the measured mean absolute error of the rotation estimates for the Lissajous navigator was 38% lower (0.3 ) than for the spherical navigator (0.5 ). The maximum error of the Lissajous navigator was reduced by 48% relative to the spherical navigator. The Lissajous navigator delivers higher accuracy of rotation estimation and a higher degree of isotropy than the spherical navigator with no evident drawbacks; these are two decisive advantages, especially for high-resolution anatomical imaging.
A navigator-based rigid body motion correction for magnetic resonance imaging
Energy Technology Data Exchange (ETDEWEB)
Ullisch, Marcus Goerge
2012-01-24
A novel three-dimensional navigator k-space trajectory for rigid body motion detection for Magnetic Resonance Imaging (MRI) - the Lissajous navigator - was developed and quantitatively compared to the existing spherical navigator trajectory [1]. The spherical navigator cannot sample the complete spherical surface due to slew rate limitations of the scanner hardware. By utilizing a two dimensional Lissajous figure which is projected onto the spherical surface, the Lissajous navigator overcomes this limitation. The complete sampling of the sphere consequently leads to rotation estimates with higher and more isotropic accuracy. Simulations and phantom measurements were performed for both navigators. Both simulations and measurements show a significantly higher overall accuracy of the Lissajous navigator and a higher isotropy of the rotation estimates. Measured under identical conditions with identical postprocessing, the measured mean absolute error of the rotation estimates for the Lissajous navigator was 38% lower (0.3 ) than for the spherical navigator (0.5 ). The maximum error of the Lissajous navigator was reduced by 48% relative to the spherical navigator. The Lissajous navigator delivers higher accuracy of rotation estimation and a higher degree of isotropy than the spherical navigator with no evident drawbacks; these are two decisive advantages, especially for high-resolution anatomical imaging.
Intraoperative Spinal Navigation for the Removal of Intradural Tumors: Technical Notes.
Stefini, Roberto; Peron, Stefano; Mandelli, Jaime; Bianchini, Elena; Roccucci, Paolo
2017-08-05
In recent years, spinal surgery has incorporated the many advantages of navigation techniques to facilitate the placement of pedicle screws during osteosynthesis, mainly for degenerative diseases. However, spinal intradural tumors are not clearly visible by intraoperative fluoroscopy or computed tomography scans, thereby making navigation necessary. To evaluate the use of spinal navigation for the removal of intradural and spinal cord tumors using spinal magnetic resonance imaging (MRI) merged with intraoperative 3-dimensional (3-D) fluoro images. After fixing the patient reference frame on the spinous process, the 3-D fluoro images were obtained in the surgical room. Using this image as the reference, the preoperative volumetric MRI images and intraoperative 3-D fluoro images were merged using automated software or manually. From January to July 2016, we performed 10 navigated procedures for intradural spinal tumors by merging MRI and 3-D fluoro images. Nine patients had an intradural extramedullary tumor, 6 had neurinomas, and 3 had meningiomas; 1 patient had an intramedullary spinal cord metastasis. The surgically demonstrated benefits of spinal navigation for the removal of intradural tumors include the decreased risk of surgery at the wrong spinal level, a minimal length of skin incision and muscle strip, and a reduction in bone removal extension. Furthermore, this technique offers the advantage of opening the dura as much as is necessary and, in the case of intrinsic spinal cord tumors, it allows the tumor to be centered. Otherwise, this would not be visible, thus enabling the precise level and the posterior midline sulcus to be determined when performing a mielotomy. Copyright © 2017 by the Congress of Neurological Surgeons
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.
A high-precision instrument for analyzing nonlinear dynamic behavior of bearing cage
Energy Technology Data Exchange (ETDEWEB)
Yang, Z., E-mail: zhaohui@nwpu.edu.cn; Yu, T. [School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072 (China); Chen, H. [Xi’an Aerospace Propulsion Institute, Xi’an 710100 (China); Li, B. [State Key Laboratory for Manufacturing and Systems Engineering, Xi’an Jiaotong University, Xi’an 710054 (China)
2016-08-15
The high-precision ball bearing is fundamental to the performance of complex mechanical systems. As the speed increases, the cage behavior becomes a key factor in influencing the bearing performance, especially life and reliability. This paper develops a high-precision instrument for analyzing nonlinear dynamic behavior of the bearing cage. The trajectory of the rotational center and non-repetitive run-out (NRRO) of the cage are used to evaluate the instability of cage motion. This instrument applied an aerostatic spindle to support and spin test the bearing to decrease the influence of system error. Then, a high-speed camera is used to capture images when the bearing works at high speeds. A 3D trajectory tracking software TEMA Motion is used to track the spot which marked the cage surface. Finally, by developing the MATLAB program, a Lissajous’ figure was used to evaluate the nonlinear dynamic behavior of the cage with different speeds. The trajectory of rotational center and NRRO of the cage with various speeds are analyzed. The results can be used to predict the initial failure and optimize cage structural parameters. In addition, the repeatability precision of instrument is also validated. In the future, the motorized spindle will be applied to increase testing speed and image processing algorithms will be developed to analyze the trajectory of the cage.
A high-precision instrument for analyzing nonlinear dynamic behavior of bearing cage
International Nuclear Information System (INIS)
Yang, Z.; Yu, T.; Chen, H.; Li, B.
2016-01-01
The high-precision ball bearing is fundamental to the performance of complex mechanical systems. As the speed increases, the cage behavior becomes a key factor in influencing the bearing performance, especially life and reliability. This paper develops a high-precision instrument for analyzing nonlinear dynamic behavior of the bearing cage. The trajectory of the rotational center and non-repetitive run-out (NRRO) of the cage are used to evaluate the instability of cage motion. This instrument applied an aerostatic spindle to support and spin test the bearing to decrease the influence of system error. Then, a high-speed camera is used to capture images when the bearing works at high speeds. A 3D trajectory tracking software TEMA Motion is used to track the spot which marked the cage surface. Finally, by developing the MATLAB program, a Lissajous’ figure was used to evaluate the nonlinear dynamic behavior of the cage with different speeds. The trajectory of rotational center and NRRO of the cage with various speeds are analyzed. The results can be used to predict the initial failure and optimize cage structural parameters. In addition, the repeatability precision of instrument is also validated. In the future, the motorized spindle will be applied to increase testing speed and image processing algorithms will be developed to analyze the trajectory of the cage.
Developing and implementing a high precision setup system
Peng, Lee-Cheng
The demand for high-precision radiotherapy (HPRT) was first implemented in stereotactic radiosurgery using a rigid, invasive stereotactic head frame. Fractionated stereotactic radiotherapy (SRT) with a frameless device was developed along a growing interest in sophisticated treatment with a tight margin and high-dose gradient. This dissertation establishes the complete management for HPRT in the process of frameless SRT, including image-guided localization, immobilization, and dose evaluation. The most ideal and precise positioning system can allow for ease of relocation, real-time patient movement assessment, high accuracy, and no additional dose in daily use. A new image-guided stereotactic positioning system (IGSPS), the Align RT3C 3D surface camera system (ART, VisionRT), which combines 3D surface images and uses a real-time tracking technique, was developed to ensure accurate positioning at the first place. The uncertainties of current optical tracking system, which causes patient discomfort due to additional bite plates using the dental impression technique and external markers, are found. The accuracy and feasibility of ART is validated by comparisons with the optical tracking and cone-beam computed tomography (CBCT) systems. Additionally, an effective daily quality assurance (QA) program for the linear accelerator and multiple IGSPSs is the most important factor to ensure system performance in daily use. Currently, systematic errors from the phantom variety and long measurement time caused by switching phantoms were discovered. We investigated the use of a commercially available daily QA device to improve the efficiency and thoroughness. Reasonable action level has been established by considering dosimetric relevance and clinic flow. As for intricate treatments, the effect of dose deviation caused by setup errors remains uncertain on tumor coverage and toxicity on OARs. The lack of adequate dosimetric simulations based on the true treatment coordinates from
Vision/INS Integrated Navigation System for Poor Vision Navigation Environments
Directory of Open Access Journals (Sweden)
Youngsun Kim
2016-10-01
Full Text Available In order to improve the performance of an inertial navigation system, many aiding sensors can be used. Among these aiding sensors, a vision sensor is of particular note due to its benefits in terms of weight, cost, and power consumption. This paper proposes an inertial and vision integrated navigation method for poor vision navigation environments. The proposed method uses focal plane measurements of landmarks in order to provide position, velocity and attitude outputs even when the number of landmarks on the focal plane is not enough for navigation. In order to verify the proposed method, computer simulations and van tests are carried out. The results show that the proposed method gives accurate and reliable position, velocity and attitude outputs when the number of landmarks is insufficient.
Chen, Xiaojun; Xu, Lu; Wang, Yiping; Wang, Huixiang; Wang, Fang; Zeng, Xiangsen; Wang, Qiugen; Egger, Jan
2015-06-01
The surgical navigation system has experienced tremendous development over the past decades for minimizing the risks and improving the precision of the surgery. Nowadays, Augmented Reality (AR)-based surgical navigation is a promising technology for clinical applications. In the AR system, virtual and actual reality are mixed, offering real-time, high-quality visualization of an extensive variety of information to the users (Moussa et al., 2012) [1]. For example, virtual anatomical structures such as soft tissues, blood vessels and nerves can be integrated with the real-world scenario in real time. In this study, an AR-based surgical navigation system (AR-SNS) is developed using an optical see-through HMD (head-mounted display), aiming at improving the safety and reliability of the surgery. With the use of this system, including the calibration of instruments, registration, and the calibration of HMD, the 3D virtual critical anatomical structures in the head-mounted display are aligned with the actual structures of patient in real-world scenario during the intra-operative motion tracking process. The accuracy verification experiment demonstrated that the mean distance and angular errors were respectively 0.809±0.05mm and 1.038°±0.05°, which was sufficient to meet the clinical requirements. Copyright © 2015 Elsevier Inc. All rights reserved.
Winrow, Edward G.; Chavez, Victor H.
2011-09-01
High-precision opto-mechanical structures have historically been plagued by high costs for both hardware and the associated alignment and assembly process. This problem is especially true for space applications where only a few production units are produced. A methodology for optical alignment and optical structure design is presented which shifts the mechanism of maintaining precision from tightly toleranced, machined flight hardware to reusable, modular tooling. Using the proposed methodology, optical alignment error sources are reduced by the direct alignment of optics through their surface retroreflections (pips) as seen through a theodolite. Optical alignment adjustments are actualized through motorized, sub-micron precision actuators in 5 degrees of freedom. Optical structure hardware costs are reduced through the use of simple shapes (tubes, plates) and repeated components. This approach produces significantly cheaper hardware and more efficient assembly without sacrificing alignment precision or optical structure stability. The design, alignment plan and assembly of a 4" aperture, carbon fiber composite, Schmidt-Cassegrain concept telescope is presented.
Using cold deformation methods in flow-production of steel high precision shaped sections
International Nuclear Information System (INIS)
Zajtsev, M.L.; Makhnev, I.F.; Shkurko, I.I.
1975-01-01
A final size with a preset tolerance and a required surface finish of steel high-precision sections could be achieved by a cold deformation of hot-rolled ingots-by drawing through dismountable, monolith or roller-type drawing tools or by cold rolling in roller dies. The particularities of the both techniques are compared as regards a number of complicated shaped sections and the advantages of cold rolling are showna more uniform distribution of deformations (strain hardening) across the section, that is a greater margin of plasticity with the same reductions, the less number of the operations required. Rolling is recommended in all the cases when possible as regards the section shape and the bulk volume. The rolling-mill for the calibration of high-precision sections should have no less than two shafts (so that the size could be controlled in both directions) and arrangements to withstand high axial stresses on the rollers (the stresses appearing during rolling in skew dies). When manufacturing precise shaped sections by the cold rolling method the operations are less plentiful than in the cold drawing manufacturing
The honeycomb strip chamber: A two coordinate and high precision muon detector
International Nuclear Information System (INIS)
Tolsma, H.P.T.
1996-01-01
This thesis describes the construction and performance of the Honeycomb Strip Chamber (HSC). The HSC offers several advantages with respect to classical drift chambers and drift tubes. The main features of the HSC are: -The detector offers the possibility of simultaneous readout of two orthogonal coordinates with approximately the same precision. - The HSC technology is optimised for mass production. This means that the design is modular (monolayers) and automisation of most of the production steps is possible (folding and welding machines). - The technology is flexible. The cell diameter can easily be changed from a few millimetres to at least 20 mm by changing the parameters in the computer programme of the folding machine. The number of monolayers per station can be chosen freely to the demands of the experiment. -The honeycomb structure gives the detector stiffness and makes it self supporting. This makes the technology a very transparent one in terms of radiation length which is important to prevent multiple scattering of high energetic muons. - The dimensions of the detector are defined by high precision templates. Those templates constrain for example the overall tolerance on the wire positions to 20 μm rms. Reproduction of the high precision assembly of the detector is thus guaranteed. (orig.)
The honeycomb strip chamber: A two coordinate and high precision muon detector
Energy Technology Data Exchange (ETDEWEB)
Tolsma, H P.T.
1996-04-19
This thesis describes the construction and performance of the Honeycomb Strip Chamber (HSC). The HSC offers several advantages with respect to classical drift chambers and drift tubes. The main features of the HSC are: -The detector offers the possibility of simultaneous readout of two orthogonal coordinates with approximately the same precision. - The HSC technology is optimised for mass production. This means that the design is modular (monolayers) and automisation of most of the production steps is possible (folding and welding machines). - The technology is flexible. The cell diameter can easily be changed from a few millimetres to at least 20 mm by changing the parameters in the computer programme of the folding machine. The number of monolayers per station can be chosen freely to the demands of the experiment. -The honeycomb structure gives the detector stiffness and makes it self supporting. This makes the technology a very transparent one in terms of radiation length which is important to prevent multiple scattering of high energetic muons. - The dimensions of the detector are defined by high precision templates. Those templates constrain for example the overall tolerance on the wire positions to 20 {mu}m rms. Reproduction of the high precision assembly of the detector is thus guaranteed. (orig.).
Towards an Open Software Platform for Field Robots in Precision Agriculture
Directory of Open Access Journals (Sweden)
Kjeld Jensen
2014-06-01
Full Text Available Robotics in precision agriculture has the potential to improve competitiveness and increase sustainability compared to current crop production methods and has become an increasingly active area of research. Tractor guidance systems for supervised navigation and implement control have reached the market, and prototypes of field robots performing precision agriculture tasks without human intervention also exist. But research in advanced cognitive perception and behaviour that is required to enable a more efficient, reliable and safe autonomy becomes increasingly demanding due to the growing software complexity. A lack of collaboration between research groups contributes to the problem. Scientific publications describe methods and results from the work, but little field robot software is released and documented for others to use. We hypothesize that a common open software platform tailored to field robots in precision agriculture will significantly decrease development time and resources required to perform experiments due to efficient reuse of existing work across projects and robot platforms. In this work we present the FroboMind software platform and evaluate the performance when applied to precision agriculture tasks.
The QCD coupling and parton distributions at high precision
International Nuclear Information System (INIS)
Bluemlein, Johannes
2010-07-01
A survey is given on the present status of the nucleon parton distributions and related precision calculations and precision measurements of the strong coupling constant α s (M 2 Z ). We also discuss the impact of these quantities on precision observables at hadron colliders. (orig.)
High-Precision Mass Measurements of Exotic Nuclei with the Triple-Trap Mass Spectrometer Isoltrap
Blaum, K; Zuber, K T; Stanja, J
2002-01-01
The masses of close to 200 short-lived nuclides have already been measured with the mass spectrometer ISOLTRAP with a relative precision between 1$\\times$10$^{-7}$ and 1$\\times$10^{-8}$. The installatin of a radio-frequency quadrupole trap increased the overall efficiency by two orders of magnitude which is at present about 1%. In a recent upgrade, we installed a carbon cluster laser ion source, which will allow us to use carbon clusters as mass references for absolute mass measurements. Due to these improvements and the high reliability of ISOLTRAP we are now able to perform accurate high-precision mass measurements all over the nuclear chart. We propose therefore mass measurements on light, medium and heavy nuclides on both sides of the valley of stability in the coming four years. ISOLTRAP is presently the only instrument capable of the high precision required for many of the proposed studies.
Dual-Model Reverse CKF Algorithm in Cooperative Navigation for USV
Directory of Open Access Journals (Sweden)
Bo Xu
2014-01-01
Full Text Available As one of the most promising research directions, cooperative location with high precision and low-cost IMU is becoming an emerging research topic in many positioning fields. Low-cost MEMS/DVL is a preferred solution for dead-reckoning in multi-USV cooperative network. However, large misalignment angles and large gyro drift coexist in low-cost MEMS that leads to the poor observability. Based on cubature Kalman filter (CKF algorithm that has access to high accuracy and relative small computation, dual-model filtering scheme is proposed. It divides the whole process into two subsections that cut off the coupling relations and improve the observability of MEMS errors: it first estimates large misalignment angle and then estimates the gyro drift. Furthermore, to improve the convergence speed of large misalignment angle estimated in the first subsection, “time reversion” concept is introduced. It uses a short period time to forward and backward several times to improve convergence speed effectively. Finally, simulation analysis and experimental verification is conducted. Simulation and experimental results show that the algorithm can effectively improve the cooperative navigation performance.
GPS navigation algorithms for Autonomous Airborne Refueling of Unmanned Air Vehicles
Khanafseh, Samer Mahmoud
Unmanned Air Vehicles (UAVs) have recently generated great interest because of their potential to perform hazardous missions without risking loss of life. If autonomous airborne refueling is possible for UAVs, mission range and endurance will be greatly enhanced. However, concerns about UAV-tanker proximity, dynamic mobility and safety demand that the relative navigation system meets stringent requirements on accuracy, integrity, and continuity. In response, this research focuses on developing high-performance GPS-based navigation architectures for Autonomous Airborne Refueling (AAR) of UAVs. The AAR mission is unique because of the potentially severe sky blockage introduced by the tanker. To address this issue, a high-fidelity dynamic sky blockage model was developed and experimentally validated. In addition, robust carrier phase differential GPS navigation algorithms were derived, including a new method for high-integrity reacquisition of carrier cycle ambiguities for recently-blocked satellites. In order to evaluate navigation performance, world-wide global availability and sensitivity covariance analyses were conducted. The new navigation algorithms were shown to be sufficient for turn-free scenarios, but improvement in performance was necessary to meet the difficult requirements for a general refueling mission with banked turns. Therefore, several innovative methods were pursued to enhance navigation performance. First, a new theoretical approach was developed to quantify the position-domain integrity risk in cycle ambiguity resolution problems. A mechanism to implement this method with partially-fixed cycle ambiguity vectors was derived, and it was used to define tight upper bounds on AAR navigation integrity risk. A second method, where a new algorithm for optimal fusion of measurements from multiple antennas was developed, was used to improve satellite coverage in poor visibility environments such as in AAR. Finally, methods for using data-link extracted
Conversion Timing of Seafarer’s Decision-making for Unmanned Ship Navigation
Directory of Open Access Journals (Sweden)
Ruolan Zhang
2017-09-01
Full Text Available The aim of this study is to construct an unmanned ship swarms monitoring model to improve autonomous decision-making efficiency and safety performance of unmanned ship navigation. A framework is proposed to determine the relationship between on-board decision-making and shore side monitoring, the process of ship data detection, tracking, analysis and loss, and the application of decision-making algorithm, to discuss the different risk responses of specific unmanned ship types under various latent hazard environments, particularly in terms of precise conversion timing in switching over to remote control and full manual monitoring, to ensure safe navigation when the capability of automatic risk response inadequate. This frame-work makes it easier to train data and the adjustment for machine learning based on Bayesian risk prediction. It can be concluded that the automation level can be increased and the workload of shore-based seafarers can be reduced easily.
Intraoperative computed tomography with integrated navigation system in spinal stabilizations.
Zausinger, Stefan; Scheder, Ben; Uhl, Eberhard; Heigl, Thomas; Morhard, Dominik; Tonn, Joerg-Christian
2009-12-15
STUDY DESIGN.: A prospective interventional case-series study plus a retrospective analysis of historical patients for comparison of data. OBJECTIVE.: To evaluate workflow, feasibility, and clinical outcome of navigated stabilization procedures with data acquisition by intraoperative computed tomography. SUMMARY OF BACKGROUND DATA.: Routine fluoroscopy to assess pedicle screw placement is not consistently reliable. Our hypothesis was that image-guided spinal navigation using an intraoperative CT-scanner can improve the safety and precision of spinal stabilization surgery. METHODS.: CT data of 94 patients (thoracolumbar [n = 66], C1/2 [n = 12], cervicothoracic instability [n = 16]) were acquired after positioning the patient in the final surgical position. A sliding gantry 40-slice CT was used for image acquisition. Data were imported to a frameless infrared-based neuronavigation workstation. Intraoperative CT was obtained to assess the accuracy of instrumentation and, if necessary, the extent of decompression. All patients were clinically evaluated by Odom-criteria after surgery and after 3 months. RESULTS.: Computed accuracy of the navigation system reached /=2 mm without persistent neurologic or vascular damage in 20/414 screws (4.8%) leading to immediate correction of 10 screws (2.4%). Control-iCT changed the course of surgery in 8 cases (8.5% of all patients). The overall revision rate was 8.5% (4 wound revisions, 2 CSF fistulas, and 2 epidural hematomas). There was no reoperation due to implant malposition. According to Odom-criteria all patients experienced a clinical improvement. A retrospective analysis of 182 patients with navigated thoracolumbar transpedicular stabilizations in the preiCT era revealed an overall revision rate of 10.4% with 4.4% of patients requiring screw revision. CONCLUSION.: Intraoperative CT in combination with neuronavigation provides high accuracy of screw placement and thus safety for patients undergoing spinal stabilization
A High Precision Laser-Based Autofocus Method Using Biased Image Plane for Microscopy
Directory of Open Access Journals (Sweden)
Chao-Chen Gu
2018-01-01
Full Text Available This study designs and accomplishes a high precision and robust laser-based autofocusing system, in which a biased image plane is applied. In accordance to the designed optics, a cluster-based circle fitting algorithm is proposed to calculate the radius of the detecting spot from the reflected laser beam as an essential factor to obtain the defocus value. The experiment conduct on the experiment device achieved novel performance of high precision and robustness. Furthermore, the low demand of assembly accuracy makes the proposed method a low-cost and realizable solution for autofocusing technique.
The QCD coupling and parton distributions at high precision
Energy Technology Data Exchange (ETDEWEB)
Bluemlein, Johannes
2010-07-15
A survey is given on the present status of the nucleon parton distributions and related precision calculations and precision measurements of the strong coupling constant {alpha}{sub s}(M{sup 2}{sub Z}). We also discuss the impact of these quantities on precision observables at hadron colliders. (orig.)
Directory of Open Access Journals (Sweden)
Y. A. Bezgodkov
2011-01-01
Full Text Available Several biomechanical parameters of standing and walking in 50 patients with osteoarthrosis after total knee arthroplasty were evaluated. The patients were randomly divided in two equal groups: in the first group the surgery was performed with computer navigation system and in the second - with traditional instruments. After TKA with computer navigation centers of common body pressure and legs pressure during standing phase improved significantly better than in traditional group. Walking parameters like step length, ground contact time and rhythm coefficient improved in both groups of patients but without significant difference. Thereby more precise orientation of implant that achieved during computer assisted TKA leads to better functional performance at 6 and 12 month after surgery.
A High Fidelity Multi-Sensor Scene Understanding System for Autonomous Navigation
National Research Council Canada - National Science Library
Rosenblum, Mark; Gothard, Benny
2006-01-01
.... In the military sense, appropriate navigation implies the robot will avoid collision or contact with hazards, will not be falsely re-routed around traversible terrain due to false hazard detections...
Indoor wayfinding and navigation
2015-01-01
Due to the widespread use of navigation systems for wayfinding and navigation in the outdoors, researchers have devoted their efforts in recent years to designing navigation systems that can be used indoors. This book is a comprehensive guide to designing and building indoor wayfinding and navigation systems. It covers all types of feasible sensors (for example, Wi-Fi, A-GPS), discussing the level of accuracy, the types of map data needed, the data sources, and the techniques for providing routes and directions within structures.
Control algorithms for autonomous robot navigation
International Nuclear Information System (INIS)
Jorgensen, C.C.
1985-01-01
This paper examines control algorithm requirements for autonomous robot navigation outside laboratory environments. Three aspects of navigation are considered: navigation control in explored terrain, environment interactions with robot sensors, and navigation control in unanticipated situations. Major navigation methods are presented and relevance of traditional human learning theory is discussed. A new navigation technique linking graph theory and incidental learning is introduced
High-Precision Measurements of the Bound Electron’s Magnetic Moment
Directory of Open Access Journals (Sweden)
Sven Sturm
2017-01-01
Full Text Available Highly charged ions represent environments that allow to study precisely one or more bound electrons subjected to unsurpassed electromagnetic fields. Under such conditions, the magnetic moment (g-factor of a bound electron changes significantly, to a large extent due to contributions from quantum electrodynamics. We present three Penning-trap experiments, which allow to measure magnetic moments with ppb precision and better, serving as stringent tests of corresponding calculations, and also yielding access to fundamental quantities like the fine structure constant α and the atomic mass of the electron. Additionally, the bound electrons can be used as sensitive probes for properties of the ionic nuclei. We summarize the measurements performed so far, discuss their significance, and give a detailed account of the experimental setups, procedures and the foreseen measurements.
High-Precision Half-Life Measurements for the Superallowed Fermi β+ Emitters 14O and 18Ne
Laffoley, A. T.; Andreoiu, C.; Austin, R. A. E.; Ball, G. C.; Bender, P. C.; Bidaman, H.; Bildstein, V.; Blank, B.; Bouzomita, H.; Cross, D. S.; Deng, G.; Diaz Varela, A.; Dunlop, M. R.; Dunlop, R.; Finlay, P.; Garnsworthy, A. B.; Garrett, P.; Giovinazzo, J.; Grinyer, G. F.; Grinyer, J.; Hadinia, B.; Jamieson, D. S.; Jigmeddorj, B.; Ketelhut, S.; Kisliuk, D.; Leach, K. G.; Leslie, J. R.; MacLean, A.; Miller, D.; Mills, B.; Moukaddam, M.; Radich, A. J.; Rajabali, M. M.; Rand, E. T.; Svensson, C. E.; Tardiff, E.; Thomas, J. C.; Turko, J.; Voss, P.; Unsworth, C.
High-precision half-life measurements, at the level of ±0.04%, for the superallowed Fermi emitters 14O and 18Ne have been performed at TRIUMF's Isotope Separator and Accelerator facility. Using 3 independent detector systems, a gas-proportional counter, a fast plastic scintillator, and a high-purity germanium array, a series of direct β and γ counting measurements were performed for each of the isotopes. In the case of 14O, these measurements were made to help resolve an existing discrepancy between detection methods, whereas for 18Ne the half-life precision has been improved in anticipation of forthcoming high-precision branching ratio measurements.
SFOL Pulse: A High Accuracy DME Pulse for Alternative Aircraft Position and Navigation
Directory of Open Access Journals (Sweden)
Euiho Kim
2017-09-01
Full Text Available In the Federal Aviation Administration’s (FAA performance based navigation strategy announced in 2016, the FAA stated that it would retain and expand the Distance Measuring Equipment (DME infrastructure to ensure resilient aircraft navigation capability during the event of a Global Navigation Satellite System (GNSS outage. However, the main drawback of the DME as a GNSS back up system is that it requires a significant expansion of the current DME ground infrastructure due to its poor distance measuring accuracy over 100 m. The paper introduces a method to improve DME distance measuring accuracy by using a new DME pulse shape. The proposed pulse shape was developed by using Genetic Algorithms and is less susceptible to multipath effects so that the ranging error reduces by 36.0–77.3% when compared to the Gaussian and Smoothed Concave Polygon DME pulses, depending on noise environment.
Towards an Open Software Platform for Field Robots in Precision Agriculture
DEFF Research Database (Denmark)
Jensen, Kjeld; Larsen, Morten; Nielsen, Søren H
2014-01-01
Robotics in precision agriculture has the potential to improve competitiveness and increase sustainability compared to current crop production methods and has become an increasingly active area of research. Tractor guidance systems for supervised navigation and implement control have reached...... the market, and prototypes of field robots performing precision agriculture tasks without human intervention also exist. But research in advanced cognitive perception and behaviour that is required to enable a more efficient, reliable and safe autonomy becomes increasingly demanding due to the growing...... software complexity. A lack of collaboration between research groups contributes to the problem. Scientific publications describe methods and results from the work, but little field robot software is released and documented for others to use. We hypothesize that a common open software platform tailored...
Compendium of Neutron Beam Facilities for High Precision Nuclear Data Measurements
International Nuclear Information System (INIS)
2014-07-01
The recent advances in the development of nuclear science and technology, demonstrating the globally growing economy, require highly accurate, powerful simulations and precise analysis of the experimental results. Confidence in these results is still determined by the accuracy of the atomic and nuclear input data. For studying material response, neutron beams produced from accelerators and research reactors in broad energy spectra are reliable and indispensable tools to obtain high accuracy experimental results for neutron induced reactions. The IAEA supports the accomplishment of high precision nuclear data using nuclear facilities in particular, based on particle accelerators and research reactors around the world. Such data are essential for numerous applications in various industries and research institutions, including the safety and economical operation of nuclear power plants, future fusion reactors, nuclear medicine and non-destructive testing technologies. The IAEA organized and coordinated the technical meeting Use of Neutron Beams for High Precision Nuclear Data Measurements, in Budapest, Hungary, 10–14 December 2012. The meeting was attended by participants from 25 Member States and three international organizations — the European Organization for Nuclear Research (CERN), the Joint Research Centre (JRC) and the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (OECD/NEA). The objectives of the meeting were to provide a forum to exchange existing know-how and to share the practical experiences of neutron beam facilities and associated instrumentation, with regard to the measurement of high precision nuclear data using both accelerators and research reactors. Furthermore, the present status and future developments of worldwide accelerator and research reactor based neutron beam facilities were discussed. This publication is a summary of the technical meeting and additional materials supplied by the international
A High-precision Motion Compensation Method for SAR Based on Image Intensity Optimization
Directory of Open Access Journals (Sweden)
Hu Ke-bin
2015-02-01
Full Text Available Owing to the platform instability and precision limitations of motion sensors, motion errors negatively affect the quality of synthetic aperture radar (SAR images. The autofocus Back Projection (BP algorithm based on the optimization of image sharpness compensates for motion errors through phase error estimation. This method can attain relatively good performance, while assuming the same phase error for all pixels, i.e., it ignores the spatial variance of motion errors. To overcome this drawback, a high-precision motion error compensation method is presented in this study. In the proposed method, the Antenna Phase Centers (APC are estimated via optimization using the criterion of maximum image intensity. Then, the estimated APCs are applied for BP imaging. Because the APC estimation equals the range history estimation for each pixel, high-precision phase compensation for every pixel can be achieved. Point-target simulations and processing of experimental data validate the effectiveness of the proposed method.
Neuro-fuzzy controller to navigate an unmanned vehicle.
Selma, Boumediene; Chouraqui, Samira
2013-12-01
A Neuro-fuzzy control method for an Unmanned Vehicle (UV) simulation is described. The objective is guiding an autonomous vehicle to a desired destination along a desired path in an environment characterized by a terrain and a set of distinct objects, such as obstacles like donkey traffic lights and cars circulating in the trajectory. The autonomous navigate ability and road following precision are mainly influenced by its control strategy and real-time control performance. Fuzzy Logic Controller can very well describe the desired system behavior with simple "if-then" relations owing the designer to derive "if-then" rules manually by trial and error. On the other hand, Neural Networks perform function approximation of a system but cannot interpret the solution obtained neither check if its solution is plausible. The two approaches are complementary. Combining them, Neural Networks will allow learning capability while Fuzzy-Logic will bring knowledge representation (Neuro-Fuzzy). In this paper, an artificial neural network fuzzy inference system (ANFIS) controller is described and implemented to navigate the autonomous vehicle. Results show several improvements in the control system adjusted by neuro-fuzzy techniques in comparison to the previous methods like Artificial Neural Network (ANN).
P2. A fused silica Cherenkov detector for the high precision determination of the weak mixing angle
Energy Technology Data Exchange (ETDEWEB)
Gerz, Kathrin; Becker, Dominik; Jennewein, Thomas; Baunack, Sebastian [Johannes Gutenberg Universitaet Mainz (Germany); Kumar, Krishna [Department of Physics and Astronomy, Stony Brook University, Stony Brook (United States); Maas, Frank [Johannes Gutenberg Universitaet Mainz (Germany); Helmholtz Institut Mainz (Germany)
2016-07-01
The weak mixing angle is a central parameter of the standard model and its high precision determination is tantamount to probing for new physics effects. The P2 experiment at the MESA accelerator in Mainz will perform such a measurement of the weak mixing angle via parity violating electron-proton scattering. We aim to determine sin{sup 2}(Θ{sub W}) to a relative precision of 0.13%. Since the weak charge of the proton is small compared to its electric charge, the measurable asymmetry is only 33 ppb, requiring a challenging measurement to a precision of only 0.44 ppb. In order to achieve this precision we need to collect very high statistics and carefully minimize interfering effects like apparatus induced false asymmetries. We present the status of the development of an integrating fused-silica Cherenkov detector, which is suitable for a high precision and high intensity experiment like P2. The contribution will focus on the investigation of the detector's response to incoming signal and background particles both by simulations and by beam tests at the MAMI accelerator.
Precision axial translator with high stability.
Bösch, M A
1979-08-01
We describe a new type of translator which is inherently stable against torsion and twisting. This concentric translator is also ideally suited for precise axial motion with clearance of the center line.
High Precision Measurement of the differential vector boson cross-sections with the ATLAS detector
Armbruster, Aaron James; The ATLAS collaboration
2017-01-01
Measurements of the Drell-Yan production of W and Z/gamma bosons at the LHC provide a benchmark of our understanding of perturbative QCD and probe the proton structure in a unique way. The ATLAS collaboration has performed new high precision measurements at center-of-mass energies of 7. The measurements are performed for W+, W- and Z/gamma bosons integrated and as a function of the boson or lepton rapidity and the Z/gamma* mass. Unprecedented precision is reached and strong constraints on Parton Distribution functions, in particular the strange density are found. Z cross sections are also measured at center-of-mass energies of 8 eV and 13TeV, and cross-section ratios to the top-quark pair production have been derived. This ratio measurement leads to a cancellation of systematic effects and allows for a high precision comparison to the theory predictions. The cross section of single W events has also been measured precisely at center-of-mass energies of 8TeV and 13TeV and the W charge asymmetry has been determ...
Opshaug, Guttorm Ringstad
There are times and places where conventional navigation systems, such as the Global Positioning System (GPS), are unavailable due to anything from temporary signal occultations to lack of navigation system infrastructure altogether. The goal of the Leapfrog Navigation System (LNS) is to provide localized positioning services for such cases. The concept behind leapfrog navigation is to advance a group of navigation units teamwise into an area of interest. In a practical 2-D case, leapfrogging assumes known initial positions of at least two currently stationary navigation units. Two or more mobile units can then start to advance into the area of interest. The positions of the mobiles are constantly being calculated based on cross-range distance measurements to the stationary units, as well as cross-ranges among the mobiles themselves. At some point the mobile units stop, and the stationary units are released to move. This second team of units (now mobile) can then overtake the first team (now stationary) and travel even further towards the common goal of the group. Since there always is one stationary team, the position of any unit can be referenced back to the initial positions. Thus, LNS provides absolute positioning. I developed navigation algorithms needed to solve leapfrog positions based on cross-range measurements. I used statistical tools to predict how position errors would grow as a function of navigation unit geometry, cross-range measurement accuracy and previous position errors. Using this knowledge I predicted that a 4-unit Leapfrog Navigation System using 100 m baselines and 200 m leap distances could travel almost 15 km before accumulating absolute position errors of 10 m (1sigma). Finally, I built a prototype leapfrog navigation system using 4 GPS transceiver ranging units. I placed the 4 units in the vertices a 10m x 10m square, and leapfrogged the group 20 meters forwards, and then back again (40 m total travel). Average horizontal RMS position
INTEGRITY ANALYSIS OF REAL-TIME PPP TECHNIQUE WITH IGS-RTS SERVICE FOR MARITIME NAVIGATION
Directory of Open Access Journals (Sweden)
M. El-Diasty
2017-10-01
Full Text Available Open sea and inland waterways are the most widely used mode for transporting goods worldwide. It is the International Maritime Organization (IMO that defines the requirements for position fixing equipment for a worldwide radio-navigation system, in terms of accuracy, integrity, continuity, availability and coverage for the various phases of navigation. Satellite positioning systems can contribute to meet these requirements, as well as optimize marine transportation. Marine navigation usually consists of three major phases identified as Ocean/Coastal/Port approach/Inland waterway, in port navigation and automatic docking with alert limit ranges from 25 m to 0.25 m. GPS positioning is widely used for many applications and is currently recognized by IMO for a future maritime navigation. With the advancement in autonomous GPS positioning techniques such as Precise Point Positioning (PPP and with the advent of new real-time GNSS correction services such as IGS-Real-Time-Service (RTS, it is necessary to investigate the integrity of the PPP-based positioning technique along with IGS-RTS service in terms of availability and reliability for safe navigation in maritime application. This paper monitors the integrity of an autonomous real-time PPP-based GPS positioning system using the IGS real-time service (RTS for maritime applications that require minimum availability of integrity of 99.8 % to fulfil the IMO integrity standards. To examine the integrity of the real-time IGS-RTS PPP-based technique for maritime applications, kinematic data from a dual frequency GPS receiver is collected onboard a vessel and investigated with the real-time IGS-RTS PPP-based GPS positioning technique. It is shown that the availability of integrity of the real-time IGS-RTS PPP-based GPS solution is 100 % for all navigation phases and therefore fulfil the IMO integrity standards (99.8 % availability immediately (after 1 second, after 2 minutes and after 42 minutes
Integrity Analysis of Real-Time Ppp Technique with Igs-Rts Service for Maritime Navigation
El-Diasty, M.
2017-10-01
Open sea and inland waterways are the most widely used mode for transporting goods worldwide. It is the International Maritime Organization (IMO) that defines the requirements for position fixing equipment for a worldwide radio-navigation system, in terms of accuracy, integrity, continuity, availability and coverage for the various phases of navigation. Satellite positioning systems can contribute to meet these requirements, as well as optimize marine transportation. Marine navigation usually consists of three major phases identified as Ocean/Coastal/Port approach/Inland waterway, in port navigation and automatic docking with alert limit ranges from 25 m to 0.25 m. GPS positioning is widely used for many applications and is currently recognized by IMO for a future maritime navigation. With the advancement in autonomous GPS positioning techniques such as Precise Point Positioning (PPP) and with the advent of new real-time GNSS correction services such as IGS-Real-Time-Service (RTS), it is necessary to investigate the integrity of the PPP-based positioning technique along with IGS-RTS service in terms of availability and reliability for safe navigation in maritime application. This paper monitors the integrity of an autonomous real-time PPP-based GPS positioning system using the IGS real-time service (RTS) for maritime applications that require minimum availability of integrity of 99.8 % to fulfil the IMO integrity standards. To examine the integrity of the real-time IGS-RTS PPP-based technique for maritime applications, kinematic data from a dual frequency GPS receiver is collected onboard a vessel and investigated with the real-time IGS-RTS PPP-based GPS positioning technique. It is shown that the availability of integrity of the real-time IGS-RTS PPP-based GPS solution is 100 % for all navigation phases and therefore fulfil the IMO integrity standards (99.8 % availability) immediately (after 1 second), after 2 minutes and after 42 minutes of convergence
Energy Technology Data Exchange (ETDEWEB)
Bluemlein, Johannes
2012-05-15
Precision measurements together with exact theoretical calculations have led to steady progress in fundamental physics. A brief survey is given on recent developments and current achievements in the field of perturbative precision calculations in the Standard Model of the Elementary Particles and their application in current high energy collider data analyses.
International Nuclear Information System (INIS)
Bluemlein, Johannes
2012-05-01
Precision measurements together with exact theoretical calculations have led to steady progress in fundamental physics. A brief survey is given on recent developments and current achievements in the field of perturbative precision calculations in the Standard Model of the Elementary Particles and their application in current high energy collider data analyses.
Mitsuhashi, Shota; Akamatsu, Yasushi; Kobayashi, Hideo; Kusayama, Yoshihiro; Kumagai, Ken; Saito, Tomoyuki
2018-02-01
Rotational malpositioning of the tibial component can lead to poor functional outcome in TKA. Although various surgical techniques have been proposed, precise rotational placement of the tibial component was difficult to accomplish even with the use of a navigation system. The purpose of this study is to assess whether combined CT-based and image-free navigation systems replicate accurately the rotational alignment of tibial component that was preoperatively planned on CT, compared with the conventional method. We compared the number of outliers for rotational alignment of the tibial component using combined CT-based and image-free navigation systems (navigated group) with those of conventional method (conventional group). Seventy-two TKAs were performed between May 2012 and December 2014. In the navigated group, the anteroposterior axis was prepared using CT-based navigation system and the tibial component was positioned under control of the navigation. In the conventional group, the tibial component was placed with reference to the Akagi line that was determined visually. Fisher's exact probability test was performed to evaluate the results. There was a significant difference between the two groups with regard to the number of outliers: 3 outliers in the navigated group compared with 12 outliers in the conventional group (P image-free navigation systems decreased the number of rotational outliers of tibial component, and was helpful for the replication of the accurate rotational alignment of the tibial component that was preoperatively planned.
Precise Truss Assembly Using Commodity Parts and Low Precision Welding
Komendera, Erik; Reishus, Dustin; Dorsey, John T.; Doggett, W. R.; Correll, Nikolaus
2014-01-01
Hardware and software design and system integration for an intelligent precision jigging robot (IPJR), which allows high precision assembly using commodity parts and low-precision bonding, is described. Preliminary 2D experiments that are motivated by the problem of assembling space telescope optical benches and very large manipulators on orbit using inexpensive, stock hardware and low-precision welding are also described. An IPJR is a robot that acts as the precise "jigging", holding parts of a local structure assembly site in place, while an external low precision assembly agent cuts and welds members. The prototype presented in this paper allows an assembly agent (for this prototype, a human using only low precision tools), to assemble a 2D truss made of wooden dowels to a precision on the order of millimeters over a span on the order of meters. The analysis of the assembly error and the results of building a square structure and a ring structure are discussed. Options for future work, to extend the IPJR paradigm to building in 3D structures at micron precision are also summarized.
Distributed Ship Navigation Control System Based on Dual Network
Yao, Ying; Lv, Wu
2017-10-01
Navigation system is very important for ship’s normal running. There are a lot of devices and sensors in the navigation system to guarantee ship’s regular work. In the past, these devices and sensors were usually connected via CAN bus for high performance and reliability. However, as the development of related devices and sensors, the navigation system also needs the ability of high information throughput and remote data sharing. To meet these new requirements, we propose the communication method based on dual network which contains CAN bus and industrial Ethernet. Also, we import multiple distributed control terminals with cooperative strategy based on the idea of synchronizing the status by multicasting UDP message contained operation timestamp to make the system more efficient and reliable.
Precision crystal alignment for high-resolution electron microscope imaging
International Nuclear Information System (INIS)
Wood, G.J.; Beeching, M.J.
1990-01-01
One of the more difficult tasks involved in obtaining quality high-resolution electron micrographs is the precise alignment of a specimen into the required zone. The current accepted procedure, which involves changing to diffraction mode and searching for symmetric point diffraction pattern, is insensitive to small amounts of misalignment and at best qualitative. On-line analysis of the fourier space representation of the image, both for determining and correcting crystal tilt, is investigated. 8 refs., 42 figs
A high precision straw tube chamber with cathode readout
International Nuclear Information System (INIS)
Bychkov, V.N.; Golutvin, I.A.; Ershov, Yu.V.; Zubarev, E.V.; Ivanov, A.B.; Lysiakov, V.N.; Makhankov, A.V.; Movchan, S.A.; Peshekhonov, V.D.; Preda, T.
1993-01-01
The high precision straw chamber with cathode readout was constructed and investigated. The 10 mm diameter straws were made of aluminized Mylar with transparent longitudinal window. The X-coordinate information has been taken from cathode strips as induced charges and investigated with the centroid method. The spatial resolution σ x =103 μm was obtained at a signal-to-noise ratio of about 70. The possible ways to improve the signal-to-noise ratio are discussed. (orig.)
High-Precision Half-Life and Branching Ratio Measurements for the Superallowed β+ Emitter 26Alm
Finlay, P.; Svensson, C. E.; Demand, G. A.; Garrett, P. E.; Green, K. L.; Leach, K. G.; Phillips, A. A.; Rand, E. T.; Ball, G.; Bandyopadhyay, D.; Djongolov, M.; Ettenauer, S.; Hackman, G.; Pearson, C. J.; Leslie, J. R.; Andreoiu, C.; Cross, D.; Austin, R. A. E.; Grinyer, G. F.; Sumithrarachchi, C. S.; Williams, S. J.; Triambak, S.
2013-03-01
High-precision half-life and branching-ratio measurements for the superallowed β+ emitter 26Alm were performed at the TRIUMF-ISAC radioactive ion beam facility. An upper limit of ≤ 15 ppm at 90% C.L. was determined for the sum of all possible non-analogue β+/EC decay branches of 26Alm, yielding a superallowed branching ratio of 100.0000+0-0.0015%. A value of T1/2 = 6:34654(76) s was determined for the 26Alm half-life which is consistent with, but 2.5 times more precise than, the previous world average. Combining these results with world-average measurements yields an ft value of 3037.58(60) s, the most precisely determined for any superallowed emitting nucleus to date. This high-precision ft value for 26Alm provides a new benchmark to refine theoretical models of isospin-symmetry-breaking effects in superallowed β decays.
Optimal motion planning using navigation measure
Vaidya, Umesh
2018-05-01
We introduce navigation measure as a new tool to solve the motion planning problem in the presence of static obstacles. Existence of navigation measure guarantees collision-free convergence at the final destination set beginning with almost every initial condition with respect to the Lebesgue measure. Navigation measure can be viewed as a dual to the navigation function. While the navigation function has its minimum at the final destination set and peaks at the obstacle set, navigation measure takes the maximum value at the destination set and is zero at the obstacle set. A linear programming formalism is proposed for the construction of navigation measure. Set-oriented numerical methods are utilised to obtain finite dimensional approximation of this navigation measure. Application of the proposed navigation measure-based theoretical and computational framework is demonstrated for a motion planning problem in a complex fluid flow.
Proceedings, High-Precision $\\alpha_s$ Measurements from LHC to FCC-ee
Energy Technology Data Exchange (ETDEWEB)
d' Enterria, David [CERN; Skands, Peter Z. [Monash U.
2015-01-01
This document provides a writeup of all contributions to the workshop on "High precision measurements of $\\alpha_s$: From LHC to FCC-ee" held at CERN, Oct. 12--13, 2015. The workshop explored in depth the latest developments on the determination of the QCD coupling $\\alpha_s$ from 15 methods where high precision measurements are (or will be) available. Those include low-energy observables: (i) lattice QCD, (ii) pion decay factor, (iii) quarkonia and (iv) $\\tau$ decays, (v) soft parton-to-hadron fragmentation functions, as well as high-energy observables: (vi) global fits of parton distribution functions, (vii) hard parton-to-hadron fragmentation functions, (viii) jets in $e^\\pm$p DIS and $\\gamma$-p photoproduction, (ix) photon structure function in $\\gamma$-$\\gamma$, (x) event shapes and (xi) jet cross sections in $e^+e^-$ collisions, (xii) W boson and (xiii) Z boson decays, and (xiv) jets and (xv) top-quark cross sections in proton-(anti)proton collisions. The current status of the theoretical and experimental uncertainties associated to each extraction method, the improvements expected from LHC data in the coming years, and future perspectives achievable in $e^+e^-$ collisions at the Future Circular Collider (FCC-ee) with $\\cal{O}$(1--100 ab$^{-1}$) integrated luminosities yielding 10$^{12}$ Z bosons and jets, and 10$^{8}$ W bosons and $\\tau$ leptons, are thoroughly reviewed. The current uncertainty of the (preliminary) 2015 strong coupling world-average value, $\\alpha_s(m_Z)$ = 0.1177 $\\pm$ 0.0013, is about 1\\%. Some participants believed this may be reduced by a factor of three in the near future by including novel high-precision observables, although this opinion was not universally shared. At the FCC-ee facility, a factor of ten reduction in the $\\alpha_s$ uncertainty should be possible, mostly thanks to the huge Z and W data samples available.
Integrated navigation method of a marine strapdown inertial navigation system using a star sensor
International Nuclear Information System (INIS)
Wang, Qiuying; Diao, Ming; Gao, Wei; Zhu, Minghong; Xiao, Shu
2015-01-01
This paper presents an integrated navigation method of the strapdown inertial navigation system (SINS) using a star sensor. According to the principle of SINS, its own navigation information contains an error that increases with time. Hence, the inertial attitude matrix from the star sensor is introduced as the reference information to correct the SINS increases error. For the integrated navigation method, the vehicle’s attitude can be obtained in two ways: one is calculated from SINS; the other, which we have called star sensor attitude, is obtained as the product between the SINS position and the inertial attitude matrix from the star sensor. Therefore, the SINS position error is introduced in the star sensor attitude error. Based on the characteristics of star sensor attitude error and the mathematical derivation, the SINS navigation errors can be obtained by the coupling calculation between the SINS attitude and the star sensor attitude. Unlike several current techniques, the navigation process of this method is non-radiating and invulnerable to jamming. The effectiveness of this approach was demonstrated by simulation and experimental study. The results show that this integrated navigation method can estimate the attitude error and the position error of SINS. Therefore, the SINS navigation accuracy is improved. (paper)
Optimization of the data taking strategy for a high precision τ mass measurement
International Nuclear Information System (INIS)
Wang, Y.K.; Mo, X.H.; Yuan, C.Z.; Liu, J.P.
2007-01-01
To achieve a high precision τ mass (m τ ) measurement at the forthcoming high luminosity experiment, Monte Carlo simulation and sampling technique are adopted to simulate various data taking cases from which the optimal scheme is determined. The study indicates that when m τ is the sole parameter to be fit, the optimal energy for data taking is located near the τ + τ - production threshold in the vicinity of the largest derivative of the cross-section to energy; one point in the optimal position with luminosity around 63pb -1 is sufficient for getting a statistical precision of 0.1MeV/c 2 or better
Advances in the Control System for a High Precision Dissolved Organic Carbon Analyzer
Liao, M.; Stubbins, A.; Haidekker, M.
2017-12-01
Dissolved organic carbon (DOC) is a master variable in aquatic ecosystems. DOC in the ocean is one of the largest carbon stores on earth. Studies of the dynamics of DOC in the ocean and other low DOC systems (e.g. groundwater) are hindered by the lack of high precision (sub-micromolar) analytical techniques. Results are presented from efforts to construct and optimize a flow-through, wet chemical DOC analyzer. This study focused on the design, integration and optimization of high precision components and control systems required for such a system (mass flow controller, syringe pumps, gas extraction, reactor chamber with controlled UV and temperature). Results of the approaches developed are presented.
PERFORMANCE CHARACTERISTIC MEMS-BASED IMUs FOR UAVs NAVIGATION
Directory of Open Access Journals (Sweden)
H. A. Mohamed
2015-08-01
Full Text Available Accurate 3D reconstruction has become essential for non-traditional mapping applications such as urban planning, mining industry, environmental monitoring, navigation, surveillance, pipeline inspection, infrastructure monitoring, landslide hazard analysis, indoor localization, and military simulation. The needs of these applications cannot be satisfied by traditional mapping, which is based on dedicated data acquisition systems designed for mapping purposes. Recent advances in hardware and software development have made it possible to conduct accurate 3D mapping without using costly and high-end data acquisition systems. Low-cost digital cameras, laser scanners, and navigation systems can provide accurate mapping if they are properly integrated at the hardware and software levels. Unmanned Aerial Vehicles (UAVs are emerging as a mobile mapping platform that can provide additional economical and practical advantages. However, such economical and practical requirements need navigation systems that can provide uninterrupted navigation solution. Hence, testing the performance characteristics of Micro-Electro-Mechanical Systems (MEMS or low cost navigation sensors for various UAV applications is important research. This work focuses on studying the performance characteristics under different manoeuvres using inertial measurements integrated with single point positioning, Real-Time-Kinematic (RTK, and additional navigational aiding sensors. Furthermore, the performance of the inertial sensors is tested during Global Positioning System (GPS signal outage.
Model-base visual navigation of a mobile robot
International Nuclear Information System (INIS)
Roening, J.
1992-08-01
The thesis considers the problems of visual guidance of a mobile robot. A visual navigation system is formalized consisting of four basic components: world modelling, navigation sensing, navigation and action. According to this formalization an experimental system is designed and realized enabling real-world navigation experiments. A priori knowledge of the world is used for global path finding, aiding scene analysis and providing feedback information to the close the control loop between planned and actual movements. Two world models were developed. The first approach was a map-based model especially designed for low-level description of indoor environments. The other was a higher level and more symbolic representation of the surroundings utilizing the spatial graph concept. Two passive vision approaches were developed to extract navigation information. With passive three- camera stereovision a sparse depth map of the scene was produced. Another approach employed a fish-eye lens to map the entire scene of the surroundings without camera scanning. The local path planning of the system is supported by three-dimensional scene interpreter providing a partial understanding of scene contents. The interpreter consists of data-driven low-level stages and a model-driven high-level stage. Experiments were carried out in a simulator and test vehicle constructed in the laboratory. The test vehicle successfully navigated indoors
Performance Characteristic Mems-Based IMUs for UAVs Navigation
Mohamed, H. A.; Hansen, J. M.; Elhabiby, M. M.; El-Sheimy, N.; Sesay, A. B.
2015-08-01
Accurate 3D reconstruction has become essential for non-traditional mapping applications such as urban planning, mining industry, environmental monitoring, navigation, surveillance, pipeline inspection, infrastructure monitoring, landslide hazard analysis, indoor localization, and military simulation. The needs of these applications cannot be satisfied by traditional mapping, which is based on dedicated data acquisition systems designed for mapping purposes. Recent advances in hardware and software development have made it possible to conduct accurate 3D mapping without using costly and high-end data acquisition systems. Low-cost digital cameras, laser scanners, and navigation systems can provide accurate mapping if they are properly integrated at the hardware and software levels. Unmanned Aerial Vehicles (UAVs) are emerging as a mobile mapping platform that can provide additional economical and practical advantages. However, such economical and practical requirements need navigation systems that can provide uninterrupted navigation solution. Hence, testing the performance characteristics of Micro-Electro-Mechanical Systems (MEMS) or low cost navigation sensors for various UAV applications is important research. This work focuses on studying the performance characteristics under different manoeuvres using inertial measurements integrated with single point positioning, Real-Time-Kinematic (RTK), and additional navigational aiding sensors. Furthermore, the performance of the inertial sensors is tested during Global Positioning System (GPS) signal outage.
High-precision comparison of the antiproton-to-proton charge-to-mass ratio.
Ulmer, S; Smorra, C; Mooser, A; Franke, K; Nagahama, H; Schneider, G; Higuchi, T; Van Gorp, S; Blaum, K; Matsuda, Y; Quint, W; Walz, J; Yamazaki, Y
2015-08-13
Invariance under the charge, parity, time-reversal (CPT) transformation is one of the fundamental symmetries of the standard model of particle physics. This CPT invariance implies that the fundamental properties of antiparticles and their matter-conjugates are identical, apart from signs. There is a deep link between CPT invariance and Lorentz symmetry--that is, the laws of nature seem to be invariant under the symmetry transformation of spacetime--although it is model dependent. A number of high-precision CPT and Lorentz invariance tests--using a co-magnetometer, a torsion pendulum and a maser, among others--have been performed, but only a few direct high-precision CPT tests that compare the fundamental properties of matter and antimatter are available. Here we report high-precision cyclotron frequency comparisons of a single antiproton and a negatively charged hydrogen ion (H(-)) carried out in a Penning trap system. From 13,000 frequency measurements we compare the charge-to-mass ratio for the antiproton (q/m)p- to that for the proton (q/m)p and obtain (q/m)p-/(q/m)p − 1 =1(69) × 10(-12). The measurements were performed at cyclotron frequencies of 29.6 megahertz, so our result shows that the CPT theorem holds at the atto-electronvolt scale. Our precision of 69 parts per trillion exceeds the energy resolution of previous antiproton-to-proton mass comparisons as well as the respective figure of merit of the standard model extension by a factor of four. In addition, we give a limit on sidereal variations in the measured ratio of baryonic antimatter, and it sets a new limit on the gravitational anomaly parameter of |α − 1| < 8.7 × 10(-7).
High precision mass measurements in Ψ and Υ families revisited
International Nuclear Information System (INIS)
Artamonov, A.S.; Baru, S.E.; Blinov, A.E.
2000-01-01
High precision mass measurements in Ψ and Υ families performed in 1980-1984 at the VEPP-4 collider with OLYA and MD-1 detectors are revisited. The corrections for the new value of the electron mass are presented. The effect of the updated radiative corrections has been calculated for the J/Ψ(1S) and Ψ(2S) mass measurements [ru
Yang, Guowei; Sun, Changku; Wang, Peng; Xu, Yixin
2014-01-10
A high-speed scanning stroboscopic fringe-pattern projection system is designed. A high-speed rotating polygon mirror and a line-structured laser cooperate to produce stable and unambiguous stroboscopic fringe patterns. The system combines the rapidity of the grating projection with the high accuracy of the line-structured laser light source. The fringe patterns have fast frame rate, great density, high precision, and high brightness, with convenience and accuracy in adjusting brightness, frequency, linewidth, and the amount of phase shift. The characteristics and the stability of this system are verified by experiments. Experimental results show that the finest linewidth can reach 40 μm and that the minimum fringe cycle is 80 μm. Circuit modulation makes the light source system flexibly adjustable, easy to control in real time, and convenient to project various fringe patterns. Combined with different light intensity adjustment algorithms and 3D computation models, the 3D topography with high accuracy can be obtained for objects measured under different environments or objects with different sizes, morphologies, and optical properties. The proposed system shows a broad application prospect for fast 3D shape precision measurements, particularly in the industrial field of 3D online detection for precision devices.
Intelligent navigation to improve obstetrical sonography.
Yeo, Lami; Romero, Roberto
2016-04-01
'Manual navigation' by the operator is the standard method used to obtain information from two-dimensional and volumetric sonography. Two-dimensional sonography is highly operator dependent and requires extensive training and expertise to assess fetal anatomy properly. Most of the sonographic examination time is devoted to acquisition of images, while 'retrieval' and display of diagnostic planes occurs rapidly (essentially instantaneously). In contrast, volumetric sonography has a rapid acquisition phase, but the retrieval and display of relevant diagnostic planes is often time-consuming, tedious and challenging. We propose the term 'intelligent navigation' to refer to a new method of interrogation of a volume dataset whereby identification and selection of key anatomical landmarks allow the system to: 1) generate a geometrical reconstruction of the organ of interest; and 2) automatically navigate, find, extract and display specific diagnostic planes. This is accomplished using operator-independent algorithms that are both predictable and adaptive. Virtual Intelligent Sonographer Assistance (VIS-Assistance®) is a tool that allows operator-independent sonographic navigation and exploration of the surrounding structures in previously identified diagnostic planes. The advantage of intelligent (over manual) navigation in volumetric sonography is the short time required for both acquisition and retrieval and display of diagnostic planes. Intelligent navigation technology automatically realigns the volume, and reorients and standardizes the anatomical position, so that the fetus and the diagnostic planes are consistently displayed in the same manner each time, regardless of the fetal position or the initial orientation. Automatic labeling of anatomical structures, subject orientation and each of the diagnostic planes is also possible. Intelligent navigation technology can operate on conventional computers, and is not dependent on specific ultrasound platforms or on the
Self-tuning in master-slave synchronization of high-precision stage systems
Heertjes, M.F.; Temizer, B.; Schneiders, M.G.E.
2013-01-01
For synchronization of high-precision stage systems, in particular the synchronization between a wafer and a reticle stage system of a wafer scanner, a master–slave controller design is presented. The design consists of a synchronization controller based on FIR filters and a data-driven self-tuning
A Study of Particle Beam Spin Dynamics for High Precision Experiments
Energy Technology Data Exchange (ETDEWEB)
Fiedler, Andrew J. [Northern Illinois Univ., DeKalb, IL (United States)
2017-05-01
In the search for physics beyond the Standard Model, high precision experiments to measure fundamental properties of particles are an important frontier. One group of such measurements involves magnetic dipole moment (MDM) values as well as searching for an electric dipole moment (EDM), both of which could provide insights about how particles interact with their environment at the quantum level and if there are undiscovered new particles. For these types of high precision experiments, minimizing statistical uncertainties in the measurements plays a critical role. \\\\ \\indent This work leverages computer simulations to quantify the effects of statistical uncertainty for experiments investigating spin dynamics. In it, analysis of beam properties and lattice design effects on the polarization of the beam is performed. As a case study, the beam lines that will provide polarized muon beams to the Fermilab Muon \\emph{g}-2 experiment are analyzed to determine the effects of correlations between the phase space variables and the overall polarization of the muon beam.
Expected Navigation Flight Performance for the Magnetospheric Multiscale (MMS) Mission
Olson, Corwin; Wright, Cinnamon; Long, Anne
2012-01-01
The Magnetospheric Multiscale (MMS) mission consists of four formation-flying spacecraft placed in highly eccentric elliptical orbits about the Earth. The primary scientific mission objective is to study magnetic reconnection within the Earth s magnetosphere. The baseline navigation concept is the independent estimation of each spacecraft state using GPS pseudorange measurements (referenced to an onboard Ultra Stable Oscillator) and accelerometer measurements during maneuvers. State estimation for the MMS spacecraft is performed onboard each vehicle using the Goddard Enhanced Onboard Navigation System, which is embedded in the Navigator GPS receiver. This paper describes the latest efforts to characterize expected navigation flight performance using upgraded simulation models derived from recent analyses.
Computer-controlled detection system for high-precision isotope ratio measurements
International Nuclear Information System (INIS)
McCord, B.R.; Taylor, J.W.
1986-01-01
In this paper the authors describe a detection system for high-precision isotope ratio measurements. In this new system, the requirement for a ratioing digital voltmeter has been eliminated, and a standard digital voltmeter interfaced to a computer is employed. Instead of measuring the ratio of the two steadily increasing output voltages simultaneously, the digital voltmeter alternately samples the outputs at a precise rate over a certain period of time. The data are sent to the computer which calculates the rate of charge of each amplifier and divides the two rates to obtain the isotopic ratio. These results simulate a coincident measurement of the output of both integrators. The charge rate is calculated by using a linear regression method, and the standard error of the slope gives a measure of the stability of the system at the time the measurement was taken
Navigating the MESSENGER Spacecraft through End of Mission
Bryan, C. G.; Williams, B. G.; Williams, K. E.; Taylor, A. H.; Carranza, E.; Page, B. R.; Stanbridge, D. R.; Mazarico, E.; Neumann, G. A.; O'Shaughnessy, D. J.; McAdams, J. V.; Calloway, A. B.
2015-12-01
The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft orbited the planet Mercury from March 2011 until the end of April 2015, when it impacted the planetary surface after propellant reserves used to maintain the orbit were depleted. This highly successful mission was led by the principal investigator, Sean C. Solomon, of Columbia University. The Johns Hopkins University Applied Physics Laboratory (JHU/APL) designed and assembled the spacecraft and served as the home for spacecraft operations. Spacecraft navigation for the entirety of the mission was provided by the Space Navigation and Flight Dynamics Practice (SNAFD) of KinetX Aerospace. Orbit determination (OD) solutions were generated through processing of radiometric tracking data provided by NASA's Deep Space Network (DSN) using the MIRAGE suite of orbital analysis tools. The MESSENGER orbit was highly eccentric, with periapsis at a high northern latitude and periapsis altitude in the range 200-500 km for most of the orbital mission phase. In a low-altitude "hover campaign" during the final two months of the mission, periapsis altitudes were maintained within a narrow range between about 35 km and 5 km. Navigating a spacecraft so near a planetary surface presented special challenges. Tasks required to meet those challenges included the modeling and estimation of Mercury's gravity field and of solar and planetary radiation pressure, and the design of frequent orbit-correction maneuvers. Superior solar conjunction also presented observational modeling issues. One key to the overall success of the low-altitude hover campaign was a strategy to utilize data from an onboard laser altimeter as a cross-check on the navigation team's reconstructed and predicted estimates of periapsis altitude. Data obtained from the Mercury Laser Altimeter (MLA) on a daily basis provided near-real-time feedback that proved invaluable in evaluating alternative orbit estimation strategies, and
Present status and future aspects of highly precise radiotherapy
International Nuclear Information System (INIS)
Oita, Masataka; Takegawa, Yoshihiro; Maezawa, Hiroshi; Ikushima, Hitoshi; Osaki, Kyosuke; Nishitani, Hiromu
2006-01-01
This review describes about therapeutic equipments, irradiation technology, actual practice of highly precise radiotherapy (RT) and its tasks in future. Development of radiation equipments has made the therapy highly precise. At present, there are reportedly 836 linacs and 23 microtrons in Japan (March, 2005), most of which are computerized, new generation equipments. Image-guided RT, CT-linac system, real-time tumor-tracking RT (RTRT), tomotherapy and cyberknife are introduced owing to development of concerned devices and equipments. In addition, there are 7 facilities with proton and/or heavy ion beams. In parallel with the machine development above, irradiation has become to that from 2D to 3D by multi-gate technique with use of multi-leaf collimator and intensity-modulated RT is introduced. RTRT is an example of 4D RT. Practically, stereotactic irradiation (STI) to brain tumor has resulted in 1-year cumulative survival rate of 58% in 16 cases (23 foci, median size 1.2 cm and volume 0.57 ml) with median dose of 21.0 Gy in authors' hospital. STI in the early stage lung cancers is also practically conducted without severe adverse effects. Future tasks involve the further development of irradiation techniques and RT planning, QA/QC system, and raising of experts in related fields, which is a national problem. (T.I.)
Laser technology for high precision satellite tracking
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.
Results from Navigator GPS Flight Testing for the Magnetospheric MultiScale Mission
Lulich, Tyler D.; Bamford, William A.; Wintermitz, Luke M. B.; Price, Samuel R.
2012-01-01
The recent delivery of the first Goddard Space Flight Center (GSFC) Navigator Global Positioning System (GPS) receivers to the Magnetospheric MultiScale (MMS) mission spacecraft is a high water mark crowning a decade of research and development in high-altitude space-based GPS. Preceding MMS delivery, the engineering team had developed receivers to support multiple missions and mission studies, such as Low Earth Orbit (LEO) navigation for the Global Precipitation Mission (GPM), above the constellation navigation for the Geostationary Operational Environmental Satellite (GOES) proof-of-concept studies, cis-Lunar navigation with rapid re-acquisition during re-entry for the Orion Project and an orbital demonstration on the Space Shuttle during the Hubble Servicing Mission (HSM-4).
Ohba, Seigo; Yoshimura, Hitoshi; Ishimaru, Kyoko; Awara, Kousuke; Sano, Kazuo
2015-09-01
The aim of this study was to confirm the effectiveness of a real-time three-dimensional navigation system for use during various oral and maxillofacial surgeries. Five surgeries were performed with this real-time three-dimensional navigation system. For mandibular surgery, patients wore acrylic surgical splints when they underwent computed tomography examinations and the operation to maintain the mandibular position. The incidence of complications during and after surgery was assessed. No connection with the nasal cavity or maxillary sinus was observed at the maxilla during the operation. The inferior alveolar nerve was not injured directly, and any paresthesia around the lower lip and mental region had disappeared within several days after the surgery. In both maxillary and mandibular cases, there was no abnormal hemorrhage during or after the operation. Real-time three-dimensional computer-navigated surgery allows minimally invasive, safe procedures to be performed with precision. It results in minimal complications and early recovery.
Fan, Qigao; Wu, Yaheng; Hui, Jing; Wu, Lei; Yu, Zhenzhong; Zhou, Lijuan
2014-01-01
In some GPS failure conditions, positioning for mobile target is difficult. This paper proposed a new method based on INS/UWB for attitude angle and position synchronous tracking of indoor carrier. Firstly, error model of INS/UWB integrated system is built, including error equation of INS and UWB. And combined filtering model of INS/UWB is researched. Simulation results show that the two subsystems are complementary. Secondly, integrated navigation data fusion strategy of INS/UWB based on Kalman filtering theory is proposed. Simulation results show that FAKF method is better than the conventional Kalman filtering. Finally, an indoor experiment platform is established to verify the integrated navigation theory of INS/UWB, which is geared to the needs of coal mine working environment. Static and dynamic positioning results show that the INS/UWB integrated navigation system is stable and real-time, positioning precision meets the requirements of working condition and is better than any independent subsystem.
Progress Towards a High-Precision Infrared Spectroscopic Survey of the H_3^+ Ion
Perry, Adam J.; Hodges, James N.; Markus, Charles R.; Kocheril, G. Stephen; Jenkins, Paul A., II; McCall, Benjamin J.
2015-06-01
The trihydrogen cation, H_3^+, represents one of the most important and fundamental molecular systems. Having only two electrons and three nuclei, H_3^+ is the simplest polyatomic system and is a key testing ground for the development of new techniques for calculating potential energy surfaces and predicting molecular spectra. Corrections that go beyond the Born-Oppenheimer approximation, including adiabatic, non-adiabatic, relativistic, and quantum electrodynamic corrections are becoming more feasible to calculate. As a result, experimental measurements performed on the H_3^+ ion serve as important benchmarks which are used to test the predictive power of new computational methods. By measuring many infrared transitions with precision at the sub-MHz level it is possible to construct a list of the most highly precise experimental rovibrational energy levels for this molecule. Until recently, only a select handful of infrared transitions of this molecule have been measured with high precision (˜ 1 MHz). Using the technique of Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy, we are aiming to produce the largest high-precision spectroscopic dataset for this molecule to date. Presented here are the current results from our survey along with a discussion of the combination differences analysis used to extract the experimentally determined rovibrational energy levels. O. Polyansky, et al., Phil. Trans. R. Soc. A (2012), 370, 5014. M. Pavanello, et al., J. Chem. Phys. (2012), 136, 184303. L. Diniz, et al., Phys. Rev. A (2013), 88, 032506. L. Lodi, et al., Phys. Rev. A (2014), 89, 032505. J. Hodges, et al., J. Chem. Phys (2013), 139, 164201.
High precision isotopic ratio analysis of volatile metal chelates
International Nuclear Information System (INIS)
Hachey, D.L.; Blais, J.C.; Klein, P.D.
1980-01-01
High precision isotope ratio measurements have been made for a series of volatile alkaline earth and transition metal chelates using conventional GC/MS instrumentation. Electron ionization was used for alkaline earth chelates, whereas isobutane chemical ionization was used for transition metal studies. Natural isotopic abundances were determined for a series of Mg, Ca, Cr, Fe, Ni, Cu, Cd, and Zn chelates. Absolute accuracy ranged between 0.01 and 1.19 at. %. Absolute precision ranged between +-0.01-0.27 at. % (RSD +- 0.07-10.26%) for elements that contained as many as eight natural isotopes. Calibration curves were prepared using natural abundance metals and their enriched 50 Cr, 60 Ni, and 65 Cu isotopes covering the range 0.1-1010.7 at. % excess. A separate multiple isotope calibration curve was similarly prepared using enriched 60 Ni (0.02-2.15 at. % excess) and 62 Ni (0.23-18.5 at. % excess). The samples were analyzed by GC/CI/MS. Human plasma, containing enriched 26 Mg and 44 Ca, was analyzed by EI/MS. 1 figure, 5 tables
Kim-Hak, D.; Hoffnagle, J.; Rella, C.; Sun, M.
2016-12-01
Oxygen is a major and vital component of the Earth atmosphere representing about 21% of its composition. It is consumed or produced through biochemical processes such as combustion, respiration, and photosynthesis. Although atmospheric oxygen is not a greenhouse gas, it can be used as a top-down constraint on the carbon cycle. The variation observations of oxygen in the atmosphere are very small, in the order of the few ppm's. This presents the main technical challenge for measurement as a very high level of precision is required and only few methods including mass spectrometry, fuel cell, and paramagnetic are capable of overcoming it. Here we present new developments of a high-precision gas analyzer that utilizes the technique of Cavity Ring-Down Spectroscopy to measure oxygen concentration and oxygen isotope. Its compact and ruggedness design combined with high precision and long-term stability allows the user to deploy the instrument in the field for continuous monitoring of atmospheric oxygen level. Measurements have a 1-σ 5-minute averaging precision of 1-2 ppm for O2 over a dynamic range of 0-20%. We will present supplemental data acquired from our 10m tower measurements in Santa Clara, CA.
Zibner, F.; Fornaroli, C.; Holtkamp, J.; Shachaf, Lior; Kaplan, Natan; Gillner, A.
2017-08-01
High-precision laser micro machining gains more importance in industrial applications every month. Optical systems like the helical optics offer highest quality together with controllable and adjustable drilling geometry, thus as taper angle, aspect ratio and heat effected zone. The helical optics is based on a rotating Dove-prism which is mounted in a hollow shaft engine together with other optical elements like wedge prisms and plane plates. Although the achieved quality can be interpreted as extremely high the low process efficiency is a main reason that this manufacturing technology has only limited demand within the industrial market. The objective of the research studies presented in this paper is to dramatically increase process efficiency as well as process flexibility. During the last years, the average power of commercial ultra-short pulsed laser sources has increased significantly. The efficient utilization of the high average laser power in the field of material processing requires an effective distribution of the laser power onto the work piece. One approach to increase the efficiency is the application of beam splitting devices to enable parallel processing. Multi beam processing is used to parallelize the fabrication of periodic structures as most application only require a partial amount of the emitted ultra-short pulsed laser power. In order to achieve highest flexibility while using multi beam processing the single beams are diverted and re-guided in a way that enables the opportunity to process with each partial beam on locally apart probes or semimanufactures.
A full 3D-navigation system in a suitcase.
Freysinger, W; Truppe, M J; Gunkel, A R; Thumfart, W F
2001-01-01
To reduce the impact of contemporary 3D-navigation systems on the environment of typical otorhinolaryngologic operating rooms, we demonstrate that a transfer of navigation software to modern high-power notebook computers is feasible and results in a practicable way to provide positional information to a surgeon intraoperatively. The ARTMA Virtual Patient System has been implemented on a Macintosh PowerBook G3 and, in connection with the Polhemus FASTRAK digitizer, provides intraoperative positional information during endoscopic endonasal surgery. Satisfactory intraoperative navigation has been realized in two- and three-dimensional medical image data sets (i.e., X-ray, ultrasound images, CT, and MR) and live video. This proof-of-concept study demonstrates that acceptable ergonomics and excellent performance of the system can be achieved with contemporary high-end notebook computers. Copyright 2001 Wiley-Liss, Inc.
Carson, John M., III; Johnson, Andrew E.; Anderson, F. Scott; Condon, Gerald L.; Nguyen, Louis H.; Olansen, Jon B.; Devolites, Jennifer L.; Harris, William J.; Hines, Glenn D.; Lee, David E.;
2016-01-01
The Lunar MARE (Moon Age and Regolith Explorer) Discovery Mission concept targets delivery of a science payload to the lunar surface for sample collection and dating. The mission science is within a 100-meter radius region of smooth lunar maria terrain near Aristarchus crater. The location has several small, sharp craters and rocks that present landing hazards to the spacecraft. For successful delivery of the science payload to the surface, the vehicle Guidance, Navigation and Control (GN&C) subsystem requires safe and precise landing capability, so design infuses the NASA Autonomous precision Landing and Hazard Avoidance Technology (ALHAT) and a gimbaled, throttleable LOX/LCH4 main engine. The ALHAT system implemented for Lunar MARE is a specialization of prototype technologies in work within NASA for the past two decades, including a passive optical Terrain Relative Navigation (TRN) sensor, a Navigation Doppler Lidar (NDL) velocity and range sensor, and a Lidar-based Hazard Detection (HD) sensor. The landing descent profile is from a retrograde orbit over lighted terrain with landing near lunar dawn. The GN&C subsystem with ALHAT capabilities will deliver the science payload to the lunar surface within a 20-meter landing ellipse of the target location and at a site having greater than 99% safety probability, which minimizes risk to safe landing and delivery of the MARE science payload to the intended terrain region.
International Nuclear Information System (INIS)
Aggarwal, Priyanka; Syed, Zainab; El-Sheimy, Naser
2009-01-01
Navigation includes the integration of methodologies and systems for estimating time-varying position, velocity and attitude of moving objects. Navigation incorporating the integrated inertial navigation system (INS) and global positioning system (GPS) generally requires extensive evaluations of nonlinear equations involving double integration. Currently, integrated navigation systems are commonly implemented using the extended Kalman filter (EKF). The EKF assumes a linearized process, measurement models and Gaussian noise distributions. These assumptions are unrealistic for highly nonlinear systems like land vehicle navigation and may cause filter divergence. A particle filter (PF) is developed to enhance integrated INS/GPS system performance as it can easily deal with nonlinearity and non-Gaussian noises. In this paper, a hybrid extended particle filter (HEPF) is developed as an alternative to the well-known EKF to achieve better navigation data accuracy for low-cost microelectromechanical system sensors. The results show that the HEPF performs better than the EKF during GPS outages, especially when simulated outages are located in periods with high vehicle dynamics
High-precision positioning of radar scatterers
Dheenathayalan, P.; Small, D.; Schubert, A.; Hanssen, R.F.
2016-01-01
Remote sensing radar satellites cover wide areas and provide spatially dense measurements, with millions of scatterers. Knowledge of the precise position of each radar scatterer is essential to identify the corresponding object and interpret the estimated deformation. The absolute position accuracy
Lunar Navigation Architecture Design Considerations
D'Souza, Christopher; Getchius, Joel; Holt, Greg; Moreau, Michael
2009-01-01
The NASA Constellation Program is aiming to establish a long-term presence on the lunar surface. The Constellation elements (Orion, Altair, Earth Departure Stage, and Ares launch vehicles) will require a lunar navigation architecture for navigation state updates during lunar-class missions. Orion in particular has baselined earth-based ground direct tracking as the primary source for much of its absolute navigation needs. However, due to the uncertainty in the lunar navigation architecture, the Orion program has had to make certain assumptions on the capabilities of such architectures in order to adequately scale the vehicle design trade space. The following paper outlines lunar navigation requirements, the Orion program assumptions, and the impacts of these assumptions to the lunar navigation architecture design. The selection of potential sites was based upon geometric baselines, logistical feasibility, redundancy, and abort support capability. Simulated navigation covariances mapped to entry interface flightpath- angle uncertainties were used to evaluate knowledge errors. A minimum ground station architecture was identified consisting of Goldstone, Madrid, Canberra, Santiago, Hartebeeshoek, Dongora, Hawaii, Guam, and Ascension Island (or the geometric equivalent).
Large-Scale Context-Aware Volume Navigation using Dynamic Insets
Al-Awami, Ali
2012-07-01
Latest developments in electron microscopy (EM) technology produce high resolution images that enable neuro-scientists to identify and put together the complex neural connections in a nervous system. However, because of the massive size and underlying complexity of this kind of data, processing, navigation and analysis suffer drastically in terms of time and effort. In this work, we propose the use of state-of- the-art navigation techniques, such as dynamic insets, built on a peta-scale volume visualization framework to provide focus and context-awareness to help neuro-scientists in their mission to analyze, reconstruct, navigate and explore EM neuroscience data.
E-navigation Services for Non-SOLAS Ships
Directory of Open Access Journals (Sweden)
Kwang An
2016-06-01
Full Text Available It is clearly understood that the main benefits of e-navigation are improved safety and better protection of the environment through the promotion of standards of navigational system and a reduction in human error. In order to meet the expectations on the benefit of e-navigation, e-navigation services should be more focused on non-SOLAS ships. The purpose of this paper is to present necessary e-navigation services for non-SOLAS ships in order to prevent marine accidents in Korean coastal waters. To meet the objectives of the study, an examination on the present navigation and communication system for non-SOLAS ships was performed. Based on the IMO's e-navigation Strategy Implementation Plan (SIP and Korea's national SIP for e-navigation, future trends for the development and implementation of e-navigation were discussed. Consequently, Electronic Navigational Chart (ENC download and ENC up-date service, ENC streaming service, route support service and communication support service based on Maritime Cloud were presented as essential e-navigation services for non-SOLAS ships. This study will help for the planning and designing of the Korean e-navigation system. It is expected that the further researches on the navigation support systems based on e-navigation will be carried out in order to implement the essential e-navigation services for non-SOLAS ships.
High precision electron beam diagnostic system for high current long pulse beams
International Nuclear Information System (INIS)
Chen, Y J; Fessenden, T; Holmes, C; Nelson, S D; Selchow, N.
1999-01-01
As part of the effort to develop a multi-axis electron beam transport system using stripline kicker technology for DARHT II applications, it is necessary to precisely determine the position and extent of long high energy beams (6-40 MeV, 1-4 kA, 2 microseconds) for accurate position control. The kicker positioning system utilizes shot-to-shot adjustments for reduction of relatively slow (<20 MHz) motion of the beam centroid. The electron beams passing through the diagnostic systems have the potential for large halo effects that tend to corrupt measurements performed using capacitive pick-off probes. Likewise, transmission line traveling wave probes have problems with multi-bounce effects due to these longer pulse widths. Finally, the high energy densities experienced in these applications distort typical foil beam position measurements
A New High-Precision Correction Method of Temperature Distribution in Model Stellar Atmospheres
Directory of Open Access Journals (Sweden)
Sapar A.
2013-06-01
Full Text Available The main features of the temperature correction methods, suggested and used in modeling of plane-parallel stellar atmospheres, are discussed. The main features of the new method are described. Derivation of the formulae for a version of the Unsöld-Lucy method, used by us in the SMART (Stellar Model Atmospheres and Radiative Transport software for modeling stellar atmospheres, is presented. The method is based on a correction of the model temperature distribution based on minimizing differences of flux from its accepted constant value and on the requirement of the lack of its gradient, meaning that local source and sink terms of radiation must be equal. The final relative flux constancy obtainable by the method with the SMART code turned out to have the precision of the order of 0.5 %. Some of the rapidly converging iteration steps can be useful before starting the high-precision model correction. The corrections of both the flux value and of its gradient, like in Unsöld-Lucy method, are unavoidably needed to obtain high-precision flux constancy. A new temperature correction method to obtain high-precision flux constancy for plane-parallel LTE model stellar atmospheres is proposed and studied. The non-linear optimization is carried out by the least squares, in which the Levenberg-Marquardt correction method and thereafter additional correction by the Broyden iteration loop were applied. Small finite differences of temperature (δT/T = 10−3 are used in the computations. A single Jacobian step appears to be mostly sufficient to get flux constancy of the order 10−2 %. The dual numbers and their generalization – the dual complex numbers (the duplex numbers – enable automatically to get the derivatives in the nilpotent part of the dual numbers. A version of the SMART software is in the stage of refactorization to dual and duplex numbers, what enables to get rid of the finite differences, as an additional source of lowering precision of the
Validation of Navigation Ultrasound for Clavicular Length Measurement
DEFF Research Database (Denmark)
Høj, Anders Thorsmark; Villa, Chiara; Christensen, Ole M.
2017-01-01
interval): approximately ± 7.5 mm, Pearson's correlation R: 0.948-0.974). Navigation ultrasound can measure clavicular length with an intra-rater reliability matching that of 3-D rendered computed tomography scans and with high validity. Its use could spread to other fields requiring accurate...... of 52.5 (range: 21-78 y) were included. Navigation ultrasound exhibited high reliability (intra-class correlation coefficient: 0.942-0.997, standard error of the mean: 0.7-2.9 mm, minimal detectable change: 2.3-8.1 mm) and validity (measurement error: 1.3%-1.8%, limits of agreement (95% confidence...
International Nuclear Information System (INIS)
Schulz, T.; Roettger, S.; Bahner-Heyne, E.J.; Kluge, G.
2009-01-01
Purpose: investigation of the influence of CT-based navigation systems on the success of an intervention, assessment of the advantages and disadvantages of the utilized systems, and evaluation of the ergonomic system properties. Materials and method: a simple guiding system PatPos Invent trademark and the computer-based navigation system PinPoint trademark were employed on two CT systems. In order to investigate the influence of the navigation aids on the success of the interventions, 96 prospective, randomized, and standardized punctures were performed on a specifically developed, rigid phantom. 16 examiners punctured 6 targets with 3 degrees of difficulty with the navigation aids. Results: irrespective of the experience of the examiner, both navigation systems guided the target with an equal degree of certainty. PinPoint significantly reduced the length of the examination time (12 - 25 min) as compared to PatPos Invent (20 - 40 min). The expectation conformity and comprehensibility of PatPos Invent were assessed significantly more positively than PinPoint with regard to the general handling of the system. In contrast, the assessment of the usability during preoperative setup favored PinPoint. The type of navigation system has no influence on the precision of the implementation of a puncture procedure. (orig.)
A high-precision system for conformal intracranial radiotherapy
International Nuclear Information System (INIS)
Tome, Wolfgang A.; Meeks, Sanford L.; Buatti, John M.; Bova, Francis J.; Friedman, William A.; Li Zuofeng
2000-01-01
Purpose: Currently, optimally precise delivery of intracranial radiotherapy is possible with stereotactic radiosurgery and fractionated stereotactic radiotherapy. We report on an optimally precise optically guided system for three-dimensional (3D) conformal radiotherapy using multiple noncoplanar fixed fields. Methods and Materials: The optically guided system detects infrared light emitting diodes (IRLEDs) attached to a custom bite plate linked to the patient's maxillary dentition. The IRLEDs are monitored by a commercially available stereo camera system, which is interfaced to a personal computer. An IRLED reference is established with the patient at the selected stereotactic isocenter, and the computer reports the patient's current position based on the location of the IRLEDs relative to this reference position. Using this readout from the computer, the patient may be dialed directly to the desired position in stereotactic space. The patient is localized on the first day and a reference file is established for 5 different couch positions. The patient's image data are then imported into a commercial convolution-based 3D radiotherapy planning system. The previously established isocenter and couch positions are then used as a template upon which to design a conformal 3D plan with maximum beam separation. Results: The use of the optically guided system in conjunction with noncoplanar radiotherapy treatment planning using fixed fields allows the generation of highly conformal treatment plans that exhibit a high degree of dose homogeneity and a steep dose gradient. To date, this approach has been used to treat 28 patients. Conclusion: Because IRLED technology improves the accuracy of patient localization relative to the linac isocenter and allows real-time monitoring of patient position, one can choose treatment-field margins that only account for beam penumbra and image resolution without adding margin to account for larger and poorly defined setup uncertainty. This
Indoor navigation by image recognition
Choi, Io Teng; Leong, Chi Chong; Hong, Ka Wo; Pun, Chi-Man
2017-07-01
With the progress of smartphones hardware, it is simple on smartphone using image recognition technique such as face detection. In addition, indoor navigation system development is much slower than outdoor navigation system. Hence, this research proves a usage of image recognition technique for navigation in indoor environment. In this paper, we introduced an indoor navigation application that uses the indoor environment features to locate user's location and a route calculating algorithm to generate an appropriate path for user. The application is implemented on Android smartphone rather than iPhone. Yet, the application design can also be applied on iOS because the design is implemented without using special features only for Android. We found that digital navigation system provides better and clearer location information than paper map. Also, the indoor environment is ideal for Image recognition processing. Hence, the results motivate us to design an indoor navigation system using image recognition.
The STiC ASIC. High precision timing with silicon photomultipliers
International Nuclear Information System (INIS)
Harion, Tobias
2015-01-01
In recent years, Silicon Photomultipliers are being increasingly used for Time of Flight measurements in particle detectors. To utilize the high intrinsic time resolution of these sensors in detector systems, the development of specialized, highly integrated readout electronics is required. In this thesis, a mixed-signal application specific integrated circuit, named STiC, has been developed, characterized and integrated in a detector system. STiC has been specifically designed for high precision timing measurements with SiPMs, and is in particular dedicated to the EndoTOFPET-US project, which aims to achieve a coincidence time resolution of 200 ps FWHM and an energy resolution of less than 20% in an endoscopic positron emission tomography system. The chip integrates 64 high precision readout channels for SiPMs together with a digital core logic to process, store and transfer the recorded events to a data acquisition system. The performance of the chip has been validated in coincidence measurements using detector modules consisting of 3.1 x 3.1 x 15 mm 3 LYSO crystals coupled to Silicon Photomultipliers from Hamamatsu. The measurements show an energy resolution of 15% FWHM for the detection of 511 keV photons. A coincidence time resolution of 213 ps FWHM has been measured, which is among the best resolution values achieved to date with this detector topology. STiC has been integrated in the EndoTOFPET-US detector system and has been chosen as the baseline design for the readout of SiPM sensors in the Mu3e experiment.
Single Crystal Piezomotor for Large Stroke, High Precision and Cryogenic Actuations, Phase I
National Aeronautics and Space Administration — TRS Technologies proposes a novel single crystal piezomotor for large stroke, high precision, and cryogenic actuations with capability of position set-hold with...
Navigation Lights - USACE IENC
Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...
Surface navigation on Mars with a Navigation Satellite
Vijayaraghavan, A.; Thurman, Sam W.; Kahn, Robert D.; Hastrup, Rolf C.
Radiometric navigation data from the Deep Space Network (DSN) stations on the earth to transponders and other surface elements such as rovers and landers on Mars, can determine their positions to only within a kilometer in inertial space. The positional error is mostly in the z-component of the surface element parallel to the Martian spin-axis. However, with Doppler and differenced-Doppler data from a Navigation Satellite in orbit around Mars to two or more of such transponders on the planetary surface, their positions can be determined to within 15 meters (or 20 meters for one-way Doppler beacons on Mars) in inertial space. In this case, the transponders (or other vehicles) on Mars need not even be capable of directly communicating to the earth. When the Navigation Satellite data is complemented by radiometric observations from the DSN stations also, directly to the surface elements on Mars, their positions can be determined to within 3 meters in inertial space. The relative positions of such surface elements on Mars (relative to one another) in Mars-fixed coordinates, however, can be determined to within 5 meters from simply range and Doppler data from the DSN stations to the surface elements. These results are obtained from covariance studies assuming X-band data noise levels and data-arcs not exceeding 10 days. They are significant in the planning and deployment of a Mars-based navigation network necessary to support real-time operations during critical phases of manned exploration of Mars.
Energy Technology Data Exchange (ETDEWEB)
Nakamori, A.; Suzuki, T.; Mizoe, K. [Fuji Electric Corporate Research and Development,Ltd., Kanagawa (Japan)
2000-08-10
With the recent rapid spread of portable electronic appliances, specification requirements such as compact power supply and long operation with batteries have become severer. Power supply ICs (integrated circuits) are required to reduce power consumption in the circuit and perform high-precision control. To meet these requirements, Fuji Electric develops high-precision CMOS (complementary metal-oxide semiconductor) analog technology. This paper describes three analog circuit technologies of a voltage reference, an operational amplifier and a comparator as circuit components particularly important for the precision of power supply ICs. (author)
Accurate and emergent applications for high precision light small aerial remote sensing system
Pei, Liu; Yingcheng, Li; Yanli, Xue; Qingwu, Hu; Xiaofeng, Sun
2014-03-01
In this paper, we focus on the successful applications of accurate and emergent surveying and mapping for high precision light small aerial remote sensing system. First, the remote sensing system structure and three integrated operation modes will be introduced. It can be combined to three operation modes depending on the application requirements. Second, we describe the preliminary results of a precision validation method for POS direct orientation in 1:500 mapping. Third, it presents two fast response mapping products- regional continuous three-dimensional model and digital surface model, taking the efficiency and accuracy evaluation of the two products as an important point. The precision of both products meets the 1:2 000 topographic map accuracy specifications in Pingdingshan area. In the end, conclusions and future work are summarized.
Accurate and emergent applications for high precision light small aerial remote sensing system
International Nuclear Information System (INIS)
Pei, Liu; Yingcheng, Li; Yanli, Xue; Xiaofeng, Sun; Qingwu, Hu
2014-01-01
In this paper, we focus on the successful applications of accurate and emergent surveying and mapping for high precision light small aerial remote sensing system. First, the remote sensing system structure and three integrated operation modes will be introduced. It can be combined to three operation modes depending on the application requirements. Second, we describe the preliminary results of a precision validation method for POS direct orientation in 1:500 mapping. Third, it presents two fast response mapping products- regional continuous three-dimensional model and digital surface model, taking the efficiency and accuracy evaluation of the two products as an important point. The precision of both products meets the 1:2 000 topographic map accuracy specifications in Pingdingshan area. In the end, conclusions and future work are summarized
Electroweak precision tests in high-energy diboson processes
Franceschini, Roberto; Panico, Giuliano; Pomarol, Alex; Riva, Francesco; Wulzer, Andrea
2018-02-01
A promising avenue to perform precision tests of the SM at the LHC is to measure differential cross-sections at high invariant mass, exploiting in this way the growth with the energy of the corrections induced by heavy new physics. We classify the leading growing-with-energy effects in longitudinal diboson and in associated Higgs production processes, showing that they can be encapsulated in four real "high-energy primary" parameters. We assess the reach on these parameters at the LHC and at future hadronic colliders, focusing in particular on the fully leptonic W Z channel that appears particularly promising. The reach is found to be superior to existing constraints by one order of magnitude, providing a test of the SM electroweak sector at the per-mille level, in competition with LEP bounds. Unlike LHC run-1 bounds, which only apply to new physics effects that are much larger than the SM in the high-energy tail of the distributions, the probe we study applies to a wider class of new physics scenarios where such large departures are not expected.
A novel approach for pulse width measurements with a high precision (8 ps RMS) TDC in an FPGA
International Nuclear Information System (INIS)
Ugur, C.; Linev, S.; Schweitzer, T.; Traxler, M.; Michel, J.
2016-01-01
High precision time measurements are a crucial element in particle identification experiments, which likewise require pulse width information for Time-over-Threshold (ToT) measurements and charge measurements (correlated with pulse width). In almost all of the FPGA-based TDC applications, pulse width measurements are implemented using two of the TDC channels for leading and trailing edge time measurements individually. This method however, requires twice the number of resources. In this paper we present the latest precision improvements in the high precision TDC (8 ps RMS) developed before [1], as well as the novel way of measuring ToT using a single TDC channel, while still achieving high precision (as low as 11.7 ps RMS). The effect of voltage, generated by a DC-DC converter, over the precision is also discussed. Finally, the outcome of the temperature change over the pulse width measurement is shown and a correction method is suggested to limit the degradation
Tu, Rui; Zhang, Rui; Zhang, Pengfei; Liu, Jinhai; Lu, Xiaochun
2018-07-01
This study proposes an approach to facilitate real-time fast point positioning of the BeiDou Navigation Satellite System (BDS) based on regional augmentation information. We term this as the precise positioning based on augmentation information (BPP) approach. The coordinates of the reference stations were highly constrained to extract the augmentation information, which contained not only the satellite orbit clock error correlated with the satellite running state, but also included the atmosphere error and unmodeled error, which are correlated with the spatial and temporal states. Based on these mixed augmentation corrections, a precise point positioning (PPP) model could be used for the coordinates estimation of the user stations, and the float ambiguity could be easily fixed for the single-difference between satellites. Thus, this technique provided a quick and high-precision positioning service. Three different datasets with small, medium, and large baselines (0.6 km, 30 km and 136 km) were used to validate the feasibility and effectiveness of the proposed BPP method. The validations showed that using the BPP model, 1–2 cm positioning service can be provided in a 100 km wide area after just 2 s of initialization. Thus, as the proposed approach not only capitalized on both PPP and RTK but also provided consistent application, it can be used for area augmentation positioning.
Autonomous Magnetic Microrobots by Navigating Gates for Multiple Biomolecules Delivery.
Hu, Xinghao; Lim, Byeonghwa; Torati, Sri Ramulu; Ding, Junjia; Novosad, Valentine; Im, Mi-Young; Reddy, Venu; Kim, Kunwoo; Jung, Eunjoo; Shawl, Asif Iqbal; Kim, Eunjoo; Kim, CheolGi
2018-05-08
The precise delivery of biofunctionalized matters is of great interest from the fundamental and applied viewpoints. In spite of significant progress achieved during the last decade, a parallel and automated isolation and manipulation of rare analyte, and their simultaneous on-chip separation and trapping, still remain challenging. Here, a universal micromagnet junction for self-navigating gates of microrobotic particles to deliver the biomolecules to specific sites using a remote magnetic field is described. In the proposed concept, the nonmagnetic gap between the lithographically defined donor and acceptor micromagnets creates a crucial energy barrier to restrict particle gating. It is shown that by carefully designing the geometry of the junctions, it becomes possible to deliver multiple protein-functionalized carriers in high resolution, as well as MCF-7 and THP-1 cells from the mixture, with high fidelity and trap them in individual apartments. Integration of such junctions with magnetophoretic circuitry elements could lead to novel platforms without retrieving for the synchronous digital manipulation of particles/biomolecules in microfluidic multiplex arrays for next-generation biochips. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Comparison of three filters in asteroid-based autonomous navigation
International Nuclear Information System (INIS)
Cui Wen; Zhu Kai-Jian
2014-01-01
At present, optical autonomous navigation has become a key technology in deep space exploration programs. Recent studies focus on the problem of orbit determination using autonomous navigation, and the choice of filter is one of the main issues. To prepare for a possible exploration mission to Mars, the primary emphasis of this paper is to evaluate the capability of three filters, the extended Kalman filter (EKF), unscented Kalman filter (UKF) and weighted least-squares (WLS) algorithm, which have different initial states during the cruise phase. One initial state is assumed to have high accuracy with the support of ground tracking when autonomous navigation is operating; for the other state, errors are set to be large without this support. In addition, the method of selecting asteroids that can be used for navigation from known lists of asteroids to form a sequence is also presented in this study. The simulation results show that WLS and UKF should be the first choice for optical autonomous navigation during the cruise phase to Mars
Precision Muon Tracking Detectors for High-Energy Hadron Colliders
Gadow, Philipp; Kroha, Hubert; Richter, Robert
2016-01-01
Small-diameter muon drift tube (sMDT) chambers with 15 mm tube diameter are a cost-effective technology for high-precision muon tracking over large areas at high background rates as expected at future high-energy hadron colliders including HL-LHC. The chamber design and construction procedures have been optimized for mass production and provide sense wire positioning accuracy of better than 10 ?m. The rate capability of the sMDT chambers has been extensively tested at the CERN Gamma Irradiation Facility. It exceeds the one of the ATLAS muon drift tube (MDT) chambers, which are operated at unprecedentedly high background rates of neutrons and gamma-rays, by an order of magnitude, which is sufficient for almost the whole muon detector acceptance at FCC-hh at maximum luminosity. sMDT operational and construction experience exists from ATLAS muon spectrometer upgrades which are in progress or under preparation for LHC Phase 1 and 2.
The various correction methods to the high precision aeromagnetic data
International Nuclear Information System (INIS)
Xu Guocang; Zhu Lin; Ning Yuanli; Meng Xiangbao; Zhang Hongjian
2014-01-01
In the airborne geophysical survey, an outstanding achievement first depends on the measurement precision of the instrument, and the choice of measurement conditions, the reliability of data collection, followed by the correct method of measurement data processing, the rationality of the data interpretation. Obviously, geophysical data processing is an important task for the comprehensive interpretation of the measurement results, processing method is correct or not directly related to the quality of the final results. we have developed a set of personal computer software to aeromagnetic and radiometric survey data processing in the process of actual production and scientific research in recent years, and successfully applied to the production. The processing methods and flowcharts to the high precision aromagnetic data were simply introduced in this paper. However, the mathematical techniques of the various correction programes to IGRF and flying height and magnetic diurnal variation were stressily discussed in the paper. Their processing effectness were illustrated by taking an example as well. (authors)
A high precision mass spectrometer for hydrogen isotopic analysis of water samples
International Nuclear Information System (INIS)
Murthy, M.S.; Prahallada Rao, B.S.; Handu, V.K.; Satam, J.V.
1979-01-01
A high precision mass spectrometer with two ion collector assemblies and direct on line reduction facility (with uranium at 700 0 C) for water samples for hydrogen isotopic analysis has been designed and developed. The ion source particularly gives high sensitivity and at the same tike limits the H 3 + ions to a minimum. A digital ratiometer with a H 2 + compensator has also been developed. The overall precision obtained on the spectrometer is 0.07% 2sub(sigmasub(10)) value. Typical results on the performance of the spectrometer, which is working since a year and a half are given. Possible methods of extending the ranges of concentration the spectrometer can handle, both on lower and higher sides are discussed. Problems of memory between samples are briefly listed. A multiple inlet system to overcome these problems is suggested. This will also enable faster analysis when samples of highly varying concentrations are to be analyzed. A few probable areas in which the spectrometer will be shortly put to use are given. (auth.)
High-precision and low-cost vibration generator for low-frequency calibration system
Li, Rui-Jun; Lei, Ying-Jun; Zhang, Lian-Sheng; Chang, Zhen-Xin; Fan, Kuang-Chao; Cheng, Zhen-Ying; Hu, Peng-Hao
2018-03-01
Low-frequency vibration is one of the harmful factors that affect the accuracy of micro-/nano-measuring machines because its amplitude is significantly small and it is very difficult to avoid. In this paper, a low-cost and high-precision vibration generator was developed to calibrate an optical accelerometer, which is self-designed to detect low-frequency vibration. A piezoelectric actuator is used as vibration exciter, a leaf spring made of beryllium copper is used as an elastic component, and a high-resolution, low-thermal-drift eddy current sensor is applied to investigate the vibrator’s performance. Experimental results demonstrate that the vibration generator can achieve steady output displacement with frequency range from 0.6 Hz to 50 Hz, an analytical displacement resolution of 3.1 nm and an acceleration range from 3.72 mm s-2 to 1935.41 mm s-2 with a relative standard deviation less than 1.79%. The effectiveness of the high-precision and low-cost vibration generator was verified by calibrating our optical accelerometer.
Semiotic resources for navigation
DEFF Research Database (Denmark)
Due, Brian Lystgaard; Lange, Simon Bierring
2018-01-01
This paper describes two typical semiotic resources blind people use when navigating in urban areas. Everyone makes use of a variety of interpretive semiotic resources and senses when navigating. For sighted individuals, this especially involves sight. Blind people, however, must rely on everything...... else than sight, thereby substituting sight with other modalities and distributing the navigational work to other semiotic resources. Based on a large corpus of fieldwork among blind people in Denmark, undertaking observations, interviews, and video recordings of their naturally occurring practices...... of walking and navigating, this paper shows how two prototypical types of semiotic resources function as helpful cognitive extensions: the guide dog and the white cane. This paper takes its theoretical and methodological perspective from EMCA multimodal interaction analysis....
French Meteor Network for High Precision Orbits of Meteoroids
Atreya, P.; Vaubaillon, J.; Colas, F.; Bouley, S.; Gaillard, B.; Sauli, I.; Kwon, M. K.
2011-01-01
There is a lack of precise meteoroids orbit from video observations as most of the meteor stations use off-the-shelf CCD cameras. Few meteoroids orbit with precise semi-major axis are available using film photographic method. Precise orbits are necessary to compute the dust flux in the Earth s vicinity, and to estimate the ejection time of the meteoroids accurately by comparing them with the theoretical evolution model. We investigate the use of large CCD sensors to observe multi-station meteors and to compute precise orbit of these meteoroids. An ideal spatial and temporal resolution to get an accuracy to those similar of photographic plates are discussed. Various problems faced due to the use of large CCD, such as increasing the spatial and the temporal resolution at the same time and computational problems in finding the meteor position are illustrated.
Thermal-mechanical behavior of high precision composite mirrors
Kuo, C. P.; Lou, M. C.; Rapp, D.
1993-01-01
Composite mirror panels were designed, constructed, analyzed, and tested in the framework of a NASA precision segmented reflector task. The deformations of the reflector surface during the exposure to space enviroments were predicted using a finite element model. The composite mirror panels have graphite-epoxy or graphite-cyanate facesheets, separated by an aluminum or a composite honeycomb core. It is pointed out that in order to carry out detailed modeling of composite mirrors with high accuracy, it is necessary to have temperature dependent properties of the materials involved and the type and magnitude of manufacturing errors and material nonuniformities. The structural modeling and analysis efforts addressed the impact of key design and materials parameters on the performance of mirrors.
Optimal dynamic performance for high-precision actuators/stages
International Nuclear Information System (INIS)
Preissner, C.; Lee, S.-H.; Royston, T. J.; Shu, D.
2002-01-01
System dynamic performance of actuator/stage groups, such as those found in optical instrument positioning systems and other high-precision applications, is dependent upon both individual component behavior and the system configuration. Experimental modal analysis techniques were implemented to determine the six degree of freedom stiffnesses and damping for individual actuator components. These experimental data were then used in a multibody dynamic computer model to investigate the effect of stage group configuration. Running the computer model through the possible stage configurations and observing the predicted vibratory response determined the optimal stage group configuration. Configuration optimization can be performed for any group of stages, provided there is stiffness and damping data available for the constituent pieces
33 CFR 401.54 - Interference with navigation aids.
2010-07-01
... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Interference with navigation aids. 401.54 Section 401.54 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION... with navigation aids. (a) Aids to navigation shall not be interfered with or used as moorings. (b) No...
Balaban, Richard B; Galbraith, Alison A; Burns, Marguerite E; Vialle-Valentin, Catherine E; Larochelle, Marc R; Ross-Degnan, Dennis
2015-07-01
Evidence-based interventions to reduce hospital readmissions may not generalize to resource-constrained safety-net hospitals. To determine if an intervention by patient navigators (PNs), hospital-based Community Health Workers, reduces readmissions among high risk, low socioeconomic status patients. Randomized controlled trial. General medicine inpatients having at least one of the following readmission risk factors: (1) age ≥60 years, (2) any in-network inpatient admission within the past 6 months, (3) length of stay ≥3 days, (4) admission diagnosis of heart failure, or (5) chronic obstructive pulmonary disease. The analytic sample included 585 intervention patients and 925 controls. PNs provided coaching and assistance in navigating the transition from hospital to home through hospital visits and weekly telephone outreach, supporting patients for 30 days post-discharge with discharge preparation, medication management, scheduling of follow-up appointments, communication with primary care, and symptom management. The primary outcome was in-network 30-day hospital readmissions. Secondary outcomes included rates of outpatient follow-up. We evaluated outcomes for the entire cohort and stratified by patient age >60 years (425 intervention/584 controls) and ≤60 years (160 intervention/341 controls). Overall, 30-day readmission rates did not differ between intervention and control patients. However, the two age groups demonstrated marked differences. Intervention patients >60 years showed a statistically significant adjusted absolute 4.1% decrease [95% CI: -8.0%, -0.2%] in readmission with an increase in 30-day outpatient follow-up. Intervention patients ≤60 years showed a statistically significant adjusted absolute 11.8% increase [95% CI: 4.4%, 19.0%] in readmission with no change in 30-day outpatient follow-up. A patient navigator intervention among high risk, safety-net patients decreased readmission among older patients while increasing readmissions
The πNN coupling from high precision np charge exchange at 162 MeV
International Nuclear Information System (INIS)
Nilsson, J.; Blomgren, J.; Conde, H.; Elmgren, K.; Olsson, N.; Ericson, T.E.O.; Uppsala Univ.; Jonsson, O.; Nilsson, L.; Loiseau, B.; Ringbom, A.
1995-02-01
Differential cross sections for unpolarized neutrons of 162 MeV have been measured to high precision with particular attention to the absolute normalisation. These data can be extrapolated precisely and model-independently to the pion pole and give a πNN coupling constant g 2 =14.6±0.3 or f 2 =0.0808±0.0017. This is higher than recently suggested values. (author) 24 refs.; 3 figs.; 1 tab
Anchieta, M V M; Salles, F A; Cassaro, B D; Quaresma, M M; Santos, B F O
2016-10-01
Presentation of a new cranioplasty technique employing a combination of two technologies: rapid prototyping and surgical navigation. This technique allows the reconstruction of the skull cap after the resection of a bone tumor in a single surgical time. The neurosurgeon plans the craniotomy previously on the EximiusMed software, compatible with the Eximius Surgical Navigator, both from the company Artis Tecnologia (Brazil). The navigator imports the planning and guides the surgeon during the craniotomy. The simulation of the bone fault allows the virtual reconstruction of the skull cap and the production of a personalized modelling mold using the Magics-Materialise (Belgium)-software. The mold and a replica of the bone fault are made by rapid prototyping by the company Artis Tecnologia (Brazil) and shipped under sterile conditions to the surgical center. The PMMA prosthesis is produced during the surgical act with the help of a hand press. The total time necessary for the planning and production of the modelling mold is four days. The precision of the mold is submillimetric and accurately reproduces the virtual reconstruction of the prosthesis. The production of the prosthesis during surgery takes until twenty minutes depending on the type of PMMA used. The modelling mold avoids contraction and dissipates the heat generated by the material's exothermic reaction in the polymerization phase. The craniectomy is performed with precision over the drawing made with the help of the Eximius Surgical Navigator, according to the planned measurements. The replica of the bone fault serves to evaluate the adaptation of the prosthesis as a support for the perforations and the placement of screws and fixation plates, as per the surgeon's discretion. This technique allows the adequate oncologic treatment associated with a satisfactory aesthetic result, with precision, in a single surgical time, reducing time and costs.
High-precision high-sensitivity clock recovery circuit for a mobile payment application
International Nuclear Information System (INIS)
Sun Lichong; Yan Na; Min Hao; Ren Wenliang
2011-01-01
This paper presents a fully integrated carrier clock recovery circuit for a mobile payment application. The architecture is based on a sampling-detection module and a charge pump phase locked loop. Compared with clock recovery in conventional 13.56 MHz transponders, this circuit can recover a high-precision consecutive carrier clock from the on/off keying (OOK) signal sent by interrogators. Fabricated by a SMIC 0.18-μm EEPROM CMOS process, this chip works from a single power supply as low as 1.5 V Measurement results show that this circuit provides 0.34% frequency deviation and 8 mV sensitivity. (semiconductor integrated circuits)
Chi, Chongwei; Zhang, Qian; Kou, Deqiang; Ye, Jinzuo; Mao, Yamin; Qiu, Jingdan; Wang, Jiandong; Yang, Xin; Du, Yang; Tian, Jie
2014-02-01
Currently, it has been an international focus on intraoperative precise positioning and accurate resection of tumor and metastases. The methods such as X-rays, computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) have played an important role in preoperative accurate diagnosis. However, most of them are inapplicable for intraoperative surgery. We have proposed a surgical navigation system based on optical molecular imaging technology for intraoperative detection of tumors and metastasis. This system collects images from two CCD cameras for real-time fluorescent and color imaging. For image processing, the template matching algorithm is used for multispectral image fusion. For the application of tumor detection, the mouse breast cancer cell line 4T1-luc, which shows highly metastasis, was used for tumor model establishment and a model of matrix metalloproteinase (MMP) expressing breast cancer. The tumor-bearing nude mice were given tail vein injection of MMP 750FAST (PerkinElmer, Inc. USA) probe and imaged with both bioluminescence and fluorescence to assess in vivo binding of the probe to the tumor and metastases sites. Hematoxylin and eosin (H&E) staining was performed to confirm the presence of tumor and metastasis. As a result, one tumor can be observed visually in vivo. However liver metastasis has been detected under surgical navigation system and all were confirmed by histology. This approach helps surgeons to find orthotopic tumors and metastasis during intraoperative resection and visualize tumor borders for precise positioning. Further investigation is needed for future application in clinics.
A high-precision synchronization circuit for clock distribution
International Nuclear Information System (INIS)
Lu Chong; Tan Hongzhou; Duan Zhikui; Ding Yi
2015-01-01
In this paper, a novel structure of a high-precision synchronization circuit, HPSC, using interleaved delay units and a dynamic compensation circuit is proposed. HPSCs are designed for synchronization of clock distribution networks in large-scale integrated circuits, where high-quality clocks are required. The application of a hybrid structure of a coarse delay line and dynamic compensation circuit performs roughly the alignment of the clock signal in two clock cycles, and finishes the fine tuning in the next three clock cycles with the phase error suppressed under 3.8 ps. The proposed circuit is implemented and fabricated using a SMIC 0.13 μm 1P6M process with a supply voltage at 1.2 V. The allowed operation frequency ranges from 200 to 800 MHz, and the duty cycle ranges between [20%, 80%]. The active area of the core circuits is 245 × 134 μm 2 , and the power consumption is 1.64 mW at 500 MHz. (paper)
Navigating Community College Transfer in Science, Technical, Engineering, and Mathematics Fields
Packard, Becky Wai-Ling; Gagnon, Janelle L.; Senas, Arleen J.
2012-01-01
Given financial barriers facing community college students today, and workforce projections in science, technical, engineering, and math (STEM) fields, the costs of unnecessary delays while navigating transfer pathways are high. In this phenomenological study, we analyzed the delay experiences of 172 students (65% female) navigating community…
MiniDSS: a low-power and high-precision miniaturized digital sun sensor
Boer, B.M. de; Durkut, M.; Laan, E.; Hakkesteegt, H.; Theuwissen, A.; Xie, N.; Leijtens, J.L.; Urquijo, E.; Bruins, P.
2012-01-01
A high-precision and low-power miniaturized digital sun sensor has been developed at TNO. The single-chip sun sensor comprises an application specific integrated circuit (ASIC) on which an active pixel sensor (APS), read-out and processing circuitry as well as communication circuitry are combined.
Spatial navigation – a unique window into physiological and pathological aging
Directory of Open Access Journals (Sweden)
Ivana eGazova
2012-06-01
Full Text Available Spatial navigation is a skill of determining and maintaining a trajectory from one place to another. Mild progressive decline of spatial navigation develops gradually during the course of physiological ageing. Nevertheless, severe spatial navigation deficit can be the first sign of incipient Alzheimer’s disease (AD, occurring in the stage of mild cognitive impairment (MCI, preceding the development of a full blown dementia. Patients with amnestic MCI, especially those with the hippocampal type of amnestic syndrome, are at very high risk of AD. These patients present with the same pattern of spatial navigation impairment as do the patients with mild AD. Spatial navigation testing of elderly as well as computer tests developed for routine clinical use thus represent a possibility for further investigation of this cognitive domain, but most of all, an opportunity for making early diagnosis of AD.
Precision machining commercialization
International Nuclear Information System (INIS)
1978-01-01
To accelerate precision machining development so as to realize more of the potential savings within the next few years of known Department of Defense (DOD) part procurement, the Air Force Materials Laboratory (AFML) is sponsoring the Precision Machining Commercialization Project (PMC). PMC is part of the Tri-Service Precision Machine Tool Program of the DOD Manufacturing Technology Five-Year Plan. The technical resources supporting PMC are provided under sponsorship of the Department of Energy (DOE). The goal of PMC is to minimize precision machining development time and cost risk for interested vendors. PMC will do this by making available the high precision machining technology as developed in two DOE contractor facilities, the Lawrence Livermore Laboratory of the University of California and the Union Carbide Corporation, Nuclear Division, Y-12 Plant, at Oak Ridge, Tennessee
Use and Protection of GPS Sidelobe Signals for Enhanced Navigation Performance in High Earth Orbit
Parker, Joel J. K.; Valdez, Jennifer E.; Bauer, Frank H.; Moreau, Michael C.
2016-01-01
GPS (Global Positioning System) Space Service Volume (SSV) signal environment is from 3,000-36,000 kilometers altitude. Current SSV specifications only capture performance provided by signals transmitted within 23.5(L1) or 26(L2-L5) off-nadir angle. Recent on-orbit data lessons learned show significant PNT (Positioning, Navigation and Timing) performance improvements when the full aggregate signal is used. Numerous military civil operational missions in High Geosynchronous Earth Orbit (HEOGEO) utilize the full signal to enhance vehicle PNT performance
Ultrasound-based tumor movement compensation during navigated laparoscopic liver interventions.
Shahin, Osama; Beširević, Armin; Kleemann, Markus; Schlaefer, Alexander
2014-05-01
Image-guided navigation aims to provide better orientation and accuracy in laparoscopic interventions. However, the ability of the navigation system to reflect anatomical changes and maintain high accuracy during the procedure is crucial. This is particularly challenging in soft organs such as the liver, where surgical manipulation causes significant tumor movements. We propose a fast approach to obtain an accurate estimation of the tumor position throughout the procedure. Initially, a three-dimensional (3D) ultrasound image is reconstructed and the tumor is segmented. During surgery, the position of the tumor is updated based on newly acquired tracked ultrasound images. The initial segmentation of the tumor is used to automatically detect the tumor and update its position in the navigation system. Two experiments were conducted. First, a controlled phantom motion using a robot was performed to validate the tracking accuracy. Second, a needle navigation scenario based on pseudotumors injected into ex vivo porcine liver was studied. In the robot-based evaluation, the approach estimated the target location with an accuracy of 0.4 ± 0.3 mm. The mean navigation error in the needle experiment was 1.2 ± 0.6 mm, and the algorithm compensated for tumor shifts up to 38 mm in an average time of 1 s. We demonstrated a navigation approach based on tracked laparoscopic ultrasound (LUS), and focused on the neighborhood of the tumor. Our experimental results indicate that this approach can be used to quickly and accurately compensate for tumor movements caused by surgical manipulation during laparoscopic interventions. The proposed approach has the advantage of being based on the routinely used LUS; however, it upgrades its functionality to estimate the tumor position in 3D. Hence, the approach is repeatable throughout surgery, and enables high navigation accuracy to be maintained.
An Approach for High-precision Stand-alone Positioning in a Dynamic Environment
Halis Saka, M.; Metin Alkan, Reha; Ozpercin, Alişir
2015-04-01
once again by inversely, i.e. from the last epoch to the first one. In this way, the estimated coordinates were also controlled. The average of both computed coordinates were used as vessel coordinates and then compared with the known-coordinates those of geodetic receiver epoch by epoch. The results indicate that the calculated coordinates from the introduced method are consistent with the reference trajectory with an accuracy of about 1 decimeter. In contrast, the findings imply lower accuracy for height components with an accuracy of about 2 decimeters. This accuracy level meets the requirement of many applications including some marine applications, precise hydrographic surveying, dredging, attitude control of ships, buoys and floating platforms, marine geodesy, navigation and oceanography.
The Multi-energy High precision Data Processor Based on AD7606
Zhao, Chen; Zhang, Yanchi; Xie, Da
2017-11-01
This paper designs an information collector based on AD7606 to realize the high-precision simultaneous acquisition of multi-source information of multi-energy systems to form the information platform of the energy Internet at Laogang with electricty as its major energy source. Combined with information fusion technologies, this paper analyzes the data to improve the overall energy system scheduling capability and reliability.
International workshop on advanced materials for high precision detectors. Proceedings
International Nuclear Information System (INIS)
Nicquevert, B.; Hauviller, C.
1994-01-01
These proceedings gather together the contributions to the Workshop on Advanced Materials for High Precision Detectors, which was held from 28-30 September 1994 in Archamps, Haute-Savoie, France. This meeting brought together international experts (researchers, physicists and engineers) in the field of advanced materials and their use in high energy physics detectors or spacecraft applications. Its purpose was to discuss the status of the different materials currently in use in the structures of detectors and spacecraft, together with their actual performances, technological implications and future prospects. Environmental effects, such as those of moisture and radiation, were discussed, as were design and manufacturing technologies. Some case studies were presented. (orig.)
Application of MCU to intelligent interface of high precision magnet power supply
International Nuclear Information System (INIS)
Xu Ruinian; Li Deming
2004-01-01
Application of the high-capability MCU in the intelligent interface is introduced in this paper. A prototype of intelligent interface for high precision huge magnet power supply was developed successfully. This intelligent interface was composed of two parts: operation panel and main board, both of which adopt a MCU of PIC16F877 respectively. The interface has many advantages, such as small size, low cost and good interference immunity. (authors)
Ultra-High Precision Half-Life Measurement for the Superallowed &+circ; Emitter ^26Al^m
Finlay, P.; Demand, G.; Garrett, P. E.; Leach, K. G.; Phillips, A. A.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Grinyer, G. F.; Leslie, J. R.; Andreoiu, C.; Cross, D.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Djongolov, M.; Ettenauer, S.; Hackman, G.; Pearson, C. J.; Williams, S. J.
2009-10-01
The calculated nuclear structure dependent correction for ^26Al^m (δC-δNS= 0.305(27)% [1]) is smaller by nearly a factor of two than the other twelve precision superallowed cases, making it an ideal case to pursue a reduction in the experimental errors contributing to the Ft value. An ultra-high precision half-life measurement for the superallowed &+circ; emitter ^26Al^m has been made at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF in Vancouver, Canada. A beam of ˜10^5 ^26Al^m/s was delivered in October 2007 and its decay was observed using a 4π continuous gas flow proportional counter as part of an ongoing experimental program in superallowed Fermi β decay studies. With a statistical precision of ˜0.008%, the present work represents the single most precise measurement of any superallowed half-life to date. [4pt] [1] I.S. Towner and J.C. Hardy, Phys. Rev. C 79, 055502 (2009).
Coded aperture detector for high precision gamma-ray burst source locations
International Nuclear Information System (INIS)
Helmken, H.; Gorenstein, P.
1977-01-01
Coded aperture collimators in conjunction with position-sensitive detectors are very useful in the study of transient phenomenon because they combine broad field of view, high sensitivity, and an ability for precise source locations. Since the preceeding conference, a series of computer simulations of various detector designs have been carried out with the aid of a CDC 6400. Particular emphasis was placed on the development of a unit consisting of a one-dimensional random or periodic collimator in conjunction with a two-dimensional position-sensitive Xenon proportional counter. A configuration involving four of these units has been incorporated into the preliminary design study of the Transient Explorer (ATREX) satellite and are applicable to any SAS or HEAO type satellite mission. Results of this study, including detector response, fields of view, and source location precision, will be presented
Sánchez, Daniel; Nieh, James C.; Hénaut, Yann; Cruz, Leopoldo; Vandame, Rémy
Several studies have examined the existence of recruitment communication mechanisms in stingless bees. However, the spatial accuracy of location-specific recruitment has not been examined. Moreover, the location-specific recruitment of reactivated foragers, i.e., foragers that have previously experienced the same food source at a different location and time, has not been explicitly examined. However, such foragers may also play a significant role in colony foraging, particularly in small colonies. Here we report that reactivated Scaptotrigona mexicana foragers can recruit with high precision to a specific food location. The recruitment precision of reactivated foragers was evaluated by placing control feeders to the left and the right of the training feeder (direction-precision tests) and between the nest and the training feeder and beyond it (distance-precision tests). Reactivated foragers arrived at the correct location with high precision: 98.44% arrived at the training feeder in the direction trials (five-feeder fan-shaped array, accuracy of at least +/-6° of azimuth at 50 m from the nest), and 88.62% arrived at the training feeder in the distance trials (five-feeder linear array, accuracy of at least +/-5 m or +/-10% at 50 m from the nest). Thus, S. mexicana reactivated foragers can find the indicated food source at a specific distance and direction with high precision, higher than that shown by honeybees, Apis mellifera, which do not communicate food location at such close distances to the nest.
Flight-Test Evaluation of Kinematic Precise Point Positioning of Small UAVs
Directory of Open Access Journals (Sweden)
Jason N. Gross
2016-01-01
Full Text Available An experimental analysis of Global Positioning System (GPS flight data collected onboard a Small Unmanned Aerial Vehicle (SUAV is conducted in order to demonstrate that postprocessed kinematic Precise Point Positioning (PPP solutions with precisions approximately 6 cm 3D Residual Sum of Squares (RSOS can be obtained on SUAVs that have short duration flights with limited observational periods (i.e., only ~≤5 minutes of data. This is a significant result for the UAV flight testing community because an important and relevant benefit of the PPP technique over traditional Differential GPS (DGPS techniques, such as Real-Time Kinematic (RTK, is that there is no requirement for maintaining a short baseline separation to a differential GNSS reference station. Because SUAVs are an attractive platform for applications such as aerial surveying, precision agriculture, and remote sensing, this paper offers an experimental evaluation of kinematic PPP estimation strategies using SUAV platform data. In particular, an analysis is presented in which the position solutions that are obtained from postprocessing recorded UAV flight data with various PPP software and strategies are compared to solutions that were obtained using traditional double-differenced ambiguity fixed carrier-phase Differential GPS (CP-DGPS. This offers valuable insight to assist designers of SUAV navigation systems whose applications require precise positioning.
Thermal-mechanical behavior of high precision composite mirrors
Energy Technology Data Exchange (ETDEWEB)
Kuo, C.P.; Lou, M.C.; Rapp, D.
1993-01-01
Composite mirror panels were designed, constructed, analyzed, and tested in the framework of a NASA precision segmented reflector task. The deformations of the reflector surface during the exposure to space enviroments were predicted using a finite element model. The composite mirror panels have graphite-epoxy or graphite-cyanate facesheets, separated by an aluminum or a composite honeycomb core. It is pointed out that in order to carry out detailed modeling of composite mirrors with high accuracy, it is necessary to have temperature dependent properties of the materials involved and the type and magnitude of manufacturing errors and material nonuniformities. The structural modeling and analysis efforts addressed the impact of key design and materials parameters on the performance of mirrors. 4 refs.
Maintaining high precision of isotope ratio analysis over extended periods of time.
Brand, Willi A
2009-06-01
Stable isotope ratios are reliable and long lasting process tracers. In order to compare data from different locations or different sampling times at a high level of precision, a measurement strategy must include reliable traceability to an international stable isotope scale via a reference material (RM). Since these international RMs are available in low quantities only, we have developed our own analysis schemes involving laboratory working RM. In addition, quality assurance RMs are used to control the long-term performance of the delta-value assignments. The analysis schemes allow the construction of quality assurance performance charts over years of operation. In this contribution, the performance of three typical techniques established in IsoLab at the MPI-BGC in Jena is discussed. The techniques are (1) isotope ratio mass spectrometry with an elemental analyser for delta(15)N and delta(13)C analysis of bulk (organic) material, (2) high precision delta(13)C and delta(18)O analysis of CO(2) in clean-air samples, and (3) stable isotope analysis of water samples using a high-temperature reaction with carbon. In addition, reference strategies on a laser ablation system for high spatial resolution delta(13)C analysis in tree rings is exemplified briefly.
Vision Based Navigation for Autonomous Cooperative Docking of CubeSats
Pirat, Camille; Ankersen, Finn; Walker, Roger; Gass, Volker
2018-05-01
A realistic rendezvous and docking navigation solution applicable to CubeSats is investigated. The scalability analysis of the ESA Autonomous Transfer Vehicle Guidance, Navigation & Control (GNC) performances and the Russian docking system, shows that the docking of two CubeSats would require a lateral control performance of the order of 1 cm. Line of sight constraints and multipath effects affecting Global Navigation Satellite System (GNSS) measurements in close proximity prevent the use of this sensor for the final approach. This consideration and the high control accuracy requirement led to the use of vision sensors for the final 10 m of the rendezvous and docking sequence. A single monocular camera on the chaser satellite and various sets of Light-Emitting Diodes (LEDs) on the target vehicle ensure the observability of the system throughout the approach trajectory. The simple and novel formulation of the measurement equations allows differentiating unambiguously rotations from translations between the target and chaser docking port and allows a navigation performance better than 1 mm at docking. Furthermore, the non-linear measurement equations can be solved in order to provide an analytic navigation solution. This solution can be used to monitor the navigation filter solution and ensure its stability, adding an extra layer of robustness for autonomous rendezvous and docking. The navigation filter initialization is addressed in detail. The proposed method is able to differentiate LEDs signals from Sun reflections as demonstrated by experimental data. The navigation filter uses a comprehensive linearised coupled rotation/translation dynamics, describing the chaser to target docking port motion. The handover, between GNSS and vision sensor measurements, is assessed. The performances of the navigation function along the approach trajectory is discussed.
Walker, M.
2012-05-01
Significant differences in the rotation of the celestial dome between the tropical and temperate zones did not stop the peoples of either the tropical Pacific or temperate Europe from using geocentric astronomy to guide exploration of the oceans. Although the differences in the night sky contributed to differences between the Pacific Island and European systems for navigation at sea, the two navigation systems exhibit substantial similarities. Both systems define positions on the surface of the Earth using two coordinates that vary at right angles to each other and use stars, and to a lesser extent the sun, to determine directions. This essay explores similarities and differences in the use of geocentric astronomy for navigation at sea by the peoples of Polynesia and Europe in the late eighteenth century. Captain Cook's orders to discover the unknown southern continent after observing the transit of Venus combined with differences in language and culture to obscure the deeper similarities between the navigation systems used by Cook and the Polynesians. Although it was a further 200 years before anthropologists studied Pacific navigation, collaborations in voyaging with communities in Oceania demonstrated the effectiveness of Pacific navigation systems, revived interest in traditional voyaging in island communities around the Pacific, and potentially open the way for further collaborations in other areas.
Recent developments for high-precision mass measurements of the heaviest elements at SHIPTRAP
International Nuclear Information System (INIS)
Minaya Ramirez, E.; Ackermann, D.; Blaum, K.; Block, M.; Droese, C.; Düllmann, Ch. E.; Eibach, M.; Eliseev, S.; Haettner, E.; Herfurth, F.; Heßberger, F.P.
2013-01-01
Highlights: • Direct high-precision mass measurements of No and Lr isotopes performed. • High-precision mass measurements with a count rate of 1 ion/hour demonstrated. • The results provide anchor points for a large region connected by alpha-decay chains. • The binding energies determine the strength of the deformed shell closure N = 152. • Technical developments and new techniques will pave the way towards heavier elements. -- Abstract: Atomic nuclei far from stability continue to challenge our understanding. For example, theoretical models have predicted an “island of stability” in the region of the superheavy elements due to the closure of spherical proton and neutron shells. Depending on the model, these are expected at Z = 114, 120 or even 126 and N = 172 or 184. Valuable information on the road to the island of stability is derived from high-precision mass measurements, which give direct access to binding energies of short-lived trans-uranium nuclei. Recently, direct mass measurements at SHIPTRAP have been extended to nobelium and lawrencium isotopes around the deformed shell gap N = 152. In order to further extend mass measurements to the region of superheavy elements, new technical developments are required to increase the performance of our setup. The sensitivity will increase through the implementation of a new detection method, where observation of one single ion is sufficient. Together with the use of a more efficient gas stopping cell, this will us allow to significantly enhance the overall efficiency of SHIPTRAP
High-precision measurement of the 19Ne half-life and implications for right-handed weak currents.
Triambak, S; Finlay, P; Sumithrarachchi, C S; Hackman, G; Ball, G C; Garrett, P E; Svensson, C E; Cross, D S; Garnsworthy, A B; Kshetri, R; Orce, J N; Pearson, M R; Tardiff, E R; Al-Falou, H; Austin, R A E; Churchman, R; Djongolov, M K; D'Entremont, R; Kierans, C; Milovanovic, L; O'Hagan, S; Reeve, S; Sjue, S K L; Williams, S J
2012-07-27
We report a precise determination of the (19)Ne half-life to be T(1/2)=17.262±0.007 s. This result disagrees with the most recent precision measurements and is important for placing bounds on predicted right-handed interactions that are absent in the current standard model. We are able to identify and disentangle two competing systematic effects that influence the accuracy of such measurements. Our findings prompt a reassessment of results from previous high-precision lifetime measurements that used similar equipment and methods.
High-Precision Measurement of the Ne19 Half-Life and Implications for Right-Handed Weak Currents
Triambak, S.; Finlay, P.; Sumithrarachchi, C. S.; Hackman, G.; Ball, G. C.; Garrett, P. E.; Svensson, C. E.; Cross, D. S.; Garnsworthy, A. B.; Kshetri, R.; Orce, J. N.; Pearson, M. R.; Tardiff, E. R.; Al-Falou, H.; Austin, R. A. E.; Churchman, R.; Djongolov, M. K.; D'Entremont, R.; Kierans, C.; Milovanovic, L.; O'Hagan, S.; Reeve, S.; Sjue, S. K. L.; Williams, S. J.
2012-07-01
We report a precise determination of the Ne19 half-life to be T1/2=17.262±0.007s. This result disagrees with the most recent precision measurements and is important for placing bounds on predicted right-handed interactions that are absent in the current standard model. We are able to identify and disentangle two competing systematic effects that influence the accuracy of such measurements. Our findings prompt a reassessment of results from previous high-precision lifetime measurements that used similar equipment and methods.
Directory of Open Access Journals (Sweden)
M. Sakamoto
2012-07-01
Full Text Available In this paper, a novel technique to generate a high resolution and high precision Orthorectified Road Imagery (ORI by using spatial information acquired from a Mobile Mapping System (MMS is introduced. The MMS was equipped with multiple sensors such as GPS, IMU, odometer, 2-6 digital cameras and 2-4 laser scanners. In this study, a Triangulated Irregular Network (TIN based approach, similar to general aerial photogrammetry, was adopted to build a terrain model in order to generate ORI with high resolution and high geometric precision. Compared to aerial photogrammetry, there are several issues that are needed to be addressed. ORI is generated by merging multiple time sequence images of a short section. Hence, the influence of occlusion due to stationary objects, such as telephone poles, trees, footbridges, or moving objects, such as vehicles, pedestrians are very significant. Moreover, influences of light falloff at the edges of cameras, tone adjustment among images captured from different cameras or a round trip data acquisition of the same path, and time lag between image exposure and laser point acquisition also need to be addressed properly. The proposed method was applied to generate ORI with 1 cm resolution, from the actual MMS data sets. The ORI generated by the proposed technique was more clear, occlusion free and with higher resolution compared to the conventional orthorectified coloured point cloud imagery. Moreover, the visual interpretation of road features from the ORI was much easier. In addition, the experimental results also validated the effectiveness of proposed radiometric corrections. In occluded regions, the ORI was compensated by using other images captured from different angles. The validity of the image masking process, in the occluded regions, was also ascertained.
Navigation concepts for MR image-guided interventions.
Moche, Michael; Trampel, Robert; Kahn, Thomas; Busse, Harald
2008-02-01
The ongoing development of powerful magnetic resonance imaging techniques also allows for advanced possibilities to guide and control minimally invasive interventions. Various navigation concepts have been described for practically all regions of the body. The specific advantages and limitations of these concepts largely depend on the magnet design of the MR scanner and the interventional environment. Open MR scanners involve minimal patient transfer, which improves the interventional workflow and reduces the need for coregistration, ie, the mapping of spatial coordinates between imaging and intervention position. Most diagnostic scanners, in contrast, do not allow the physician to guide his instrument inside the magnet and, consequently, the patient needs to be moved out of the bore. Although adequate coregistration and navigation concepts for closed-bore scanners are technically more challenging, many developments are driven by the well-known capabilities of high-field systems and their better economic value. Advanced concepts such as multimodal overlays, augmented reality displays, and robotic assistance devices are still in their infancy but might propel the use of intraoperative navigation. The goal of this work is to give an update on MRI-based navigation and related techniques and to briefly discuss the clinical experience and limitations of some selected systems. (Copyright) 2008 Wiley-Liss, Inc.
2010-08-18
... 3 and 165 to reflect changes in Coast Guard internal organizational structure. Sector Portland and... 1625-ZA25 Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments, Sector... Waters; Technical, Organizational, and Conforming Amendments, Sector Columbia River.'' 2. On page 48564...
AUTOMATIC RECOGNITION OF INDOOR NAVIGATION ELEMENTS FROM KINECT POINT CLOUDS
Directory of Open Access Journals (Sweden)
L. Zeng
2017-09-01
Full Text Available This paper realizes automatically the navigating elements defined by indoorGML data standard – door, stairway and wall. The data used is indoor 3D point cloud collected by Kinect v2 launched in 2011 through the means of ORB-SLAM. By contrast, it is cheaper and more convenient than lidar, but the point clouds also have the problem of noise, registration error and large data volume. Hence, we adopt a shape descriptor – histogram of distances between two randomly chosen points, proposed by Osada and merges with other descriptor – in conjunction with random forest classifier to recognize the navigation elements (door, stairway and wall from Kinect point clouds. This research acquires navigation elements and their 3-d location information from each single data frame through segmentation of point clouds, boundary extraction, feature calculation and classification. Finally, this paper utilizes the acquired navigation elements and their information to generate the state data of the indoor navigation module automatically. The experimental results demonstrate a high recognition accuracy of the proposed method.
Automatic Recognition of Indoor Navigation Elements from Kinect Point Clouds
Zeng, L.; Kang, Z.
2017-09-01
This paper realizes automatically the navigating elements defined by indoorGML data standard - door, stairway and wall. The data used is indoor 3D point cloud collected by Kinect v2 launched in 2011 through the means of ORB-SLAM. By contrast, it is cheaper and more convenient than lidar, but the point clouds also have the problem of noise, registration error and large data volume. Hence, we adopt a shape descriptor - histogram of distances between two randomly chosen points, proposed by Osada and merges with other descriptor - in conjunction with random forest classifier to recognize the navigation elements (door, stairway and wall) from Kinect point clouds. This research acquires navigation elements and their 3-d location information from each single data frame through segmentation of point clouds, boundary extraction, feature calculation and classification. Finally, this paper utilizes the acquired navigation elements and their information to generate the state data of the indoor navigation module automatically. The experimental results demonstrate a high recognition accuracy of the proposed method.
High precision Cross-correlated imaging in Few-mode fibers
DEFF Research Database (Denmark)
Muliar, Olena; Usuga Castaneda, Mario A.; Kristensen, Torben
2017-01-01
us to distinguishing differential time delays between HOMs in the picosecond timescale. Broad wavelength scanning in combination with spectral shaping, allows us to estimate the modal behavior of FMF without prior knowledge of the fiber parameters. We performed our demonstration at wavelengths from...... existing approaches for modal content analysis, several methods as S2, C2 in time and frequency domain are available. In this contribution we will present an improved time-domain cross-correlated (C2) imaging technique for the experimental evaluation of modal properties in HOM fibers over a broad range......) in a few-mode fiber (FMF) are used as multiple spatial communication channels, comes in this context as a viable approach to enable the optimization of high-capacity links. From this perspective, it becomes highly necessary to possess a diagnostic tool for the precise modal characterization of FMFs. Among...
Navigation Architecture for a Space Mobile Network
Valdez, Jennifer E.; Ashman, Benjamin; Gramling, Cheryl; Heckler, Gregory W.; Carpenter, Russell
2016-01-01
The Tracking and Data Relay Satellite System (TDRSS) Augmentation Service for Satellites (TASS) is a proposed beacon service to provide a global, space based GPS augmentation service based on the NASA Global Differential GPS (GDGPS) System. The TASS signal will be tied to the GPS time system and usable as an additional ranging and Doppler radiometric source. Additionally, it will provide data vital to autonomous navigation in the near Earth regime, including space weather information, TDRS ephemerides, Earth Orientation Parameters (EOP), and forward commanding capability. TASS benefits include enhancing situational awareness, enabling increased autonomy, and providing near real-time command access for user platforms. As NASA Headquarters' Space Communication and Navigation Office (SCaN) begins to move away from a centralized network architecture and towards a Space Mobile Network (SMN) that allows for user initiated services, autonomous navigation will be a key part of such a system. This paper explores how a TASS beacon service enables the Space Mobile Networking paradigm, what a typical user platform would require, and provides an in-depth analysis of several navigation scenarios and operations concepts. This paper provides an overview of the TASS beacon and its role within the SMN and user community. Supporting navigation analysis is presented for two user mission scenarios: an Earth observing spacecraft in low earth orbit (LEO), and a highly elliptical spacecraft in a lunar resonance orbit. These diverse flight scenarios indicate the breadth of applicability of the TASS beacon for upcoming users within the current network architecture and in the SMN.
Martí, Luis; García, Jesús; Molina, José M.
2014-01-01
Proceedings of: 17th International Conference on Information Fusion (FUSION 2014): Salamanca, Spain 7-10 July 2014. High accuracy navigation usually require expensive sensors and/or its careful integration into a complex and finely tuned system. Smartphones pack a high number of sensors in a portable format, becoming a source of low-quality information with a high heterogeneity and redundancy. This work compares pure GNSS/INS capabilities on both types of platform, and discuss the weakness...
Improving multi-GNSS ultra-rapid orbit determination for real-time precise point positioning
Li, Xingxing; Chen, Xinghan; Ge, Maorong; Schuh, Harald
2018-03-01
Currently, with the rapid development of multi-constellation Global Navigation Satellite Systems (GNSS), the real-time positioning and navigation are undergoing dramatic changes with potential for a better performance. To provide more precise and reliable ultra-rapid orbits is critical for multi-GNSS real-time positioning, especially for the three merging constellations Beidou, Galileo and QZSS which are still under construction. In this contribution, we present a five-system precise orbit determination (POD) strategy to fully exploit the GPS + GLONASS + BDS + Galileo + QZSS observations from CDDIS + IGN + BKG archives for the realization of hourly five-constellation ultra-rapid orbit update. After adopting the optimized 2-day POD solution (updated every hour), the predicted orbit accuracy can be obviously improved for all the five satellite systems in comparison to the conventional 1-day POD solution (updated every 3 h). The orbit accuracy for the BDS IGSO satellites can be improved by about 80, 45 and 50% in the radial, cross and along directions, respectively, while the corresponding accuracy improvement for the BDS MEO satellites reaches about 50, 20 and 50% in the three directions, respectively. Furthermore, the multi-GNSS real-time precise point positioning (PPP) ambiguity resolution has been performed by using the improved precise satellite orbits. Numerous results indicate that combined GPS + BDS + GLONASS + Galileo (GCRE) kinematic PPP ambiguity resolution (AR) solutions can achieve the shortest time to first fix (TTFF) and highest positioning accuracy in all coordinate components. With the addition of the BDS, GLONASS and Galileo observations to the GPS-only processing, the GCRE PPP AR solution achieves the shortest average TTFF of 11 min with 7{°} cutoff elevation, while the TTFF of GPS-only, GR, GE and GC PPP AR solution is 28, 15, 20 and 17 min, respectively. As the cutoff elevation increases, the reliability and accuracy of GPS-only PPP AR solutions
Getting Lost Through Navigation
DEFF Research Database (Denmark)
Debus, Michael S.
2017-01-01
In this presentation, I argued two things. First, that it is navigation that lies at the core of contemporary (3D-) videogames and that its analysis is of utmost importance. Second, that this analysis needs a more rigorous differentiation between specific acts of navigation. Considering the Oxford...... in videogames is a configurational rather than an interpretational one (Eskelinen 2001). Especially in the case of game spaces, navigation appears to be of importance (Wolf 2009; Flynn 2008). Further, it does not only play a crucial role for the games themselves, but also for the experience of the player...
Inertial navigation without accelerometers
Boehm, M.
The Kennedy-Thorndike (1932) experiment points to the feasibility of fiber-optic inertial velocimeters, to which state-of-the-art technology could furnish substantial sensitivity and accuracy improvements. Velocimeters of this type would obviate the use of both gyros and accelerometers, and allow inertial navigation to be conducted together with vehicle attitude control, through the derivation of rotation rates from the ratios of the three possible velocimeter pairs. An inertial navigator and reference system based on this approach would probably have both fewer components and simpler algorithms, due to the obviation of the first level of integration in classic inertial navigators.
Resource Use and Medicare Costs During Lay Navigation for Geriatric Patients With Cancer.
Rocque, Gabrielle B; Pisu, Maria; Jackson, Bradford E; Kvale, Elizabeth A; Demark-Wahnefried, Wendy; Martin, Michelle Y; Meneses, Karen; Li, Yufeng; Taylor, Richard A; Acemgil, Aras; Williams, Courtney P; Lisovicz, Nedra; Fouad, Mona; Kenzik, Kelly M; Partridge, Edward E
2017-06-01
Lay navigators in the Patient Care Connect Program support patients with cancer from diagnosis through survivorship to end of life. They empower patients to engage in their health care and navigate them through the increasingly complex health care system. Navigation programs can improve access to care, enhance coordination of care, and overcome barriers to timely, high-quality health care. However, few data exist regarding the financial implications of implementing a lay navigation program. To examine the influence of lay navigation on health care spending and resource use among geriatric patients with cancer within The University of Alabama at Birmingham Health System Cancer Community Network. This observational study from January 1, 2012, through December 31, 2015, used propensity score-matched regression analysis to compare quarterly changes in the mean total Medicare costs and resource use between navigated patients and nonnavigated, matched comparison patients. The setting was The University of Alabama at Birmingham Health System Cancer Community Network, which includes 2 academic and 10 community cancer centers across Alabama, Georgia, Florida, Mississippi, and Tennessee. Participants were Medicare beneficiaries with cancer who received care at participating institutions from 2012 through 2015. The primary exposure was contact with a patient navigator. Navigated patients were matched to nonnavigated patients on age, race, sex, cancer acuity (high vs low), comorbidity score, and preenrollment characteristics (costs, emergency department visits, hospitalizations, intensive care unit admissions, and chemotherapy in the preenrollment quarter). Total costs to Medicare, components of cost, and resource use (emergency department visits, hospitalizations, and intensive care unit admissions). In total, 12 428 patients (mean (SD) age at cancer diagnosis, 75 (7) years; 52.0% female) were propensity score matched, including 6214 patients in the navigated group and 6214
a Precise, Low-Cost Rtk Gnss System for Uav Applications
Stempfhuber, W.; Buchholz, M.
2011-09-01
High accuracy with real-time positioning of moving objects has been considered a standard task of engineering geodesy for 10 to 15 years. An absolute positioning accuracy of 1-3 cm is generally possible worldwide and is further used in many areas of machine guidance (machine control and guidance), and farming (precision farming) as well as for various special applications (e.g. railway trolley, mining, etc.). The cost of the measuring instruments required for the use of geodetic L1/L2 receivers with a local reference station amounts to approximately USD 30,000 to 50,000. Therefore, dual frequency RTK GNSS receivers are not used in the mass market. Affordable GPS/GNSS modules have already reached the mass market in various areas such as mobile phones, car navigation, the leisure industry, etc. Kinematic real-time positioning applications with centimetre or decimetre levels could also evolve into a mass product. In order for this to happen, the costs for such systems must lie between USD 1,000 to 2,000. What exactly low-cost means is determined by the precise specifications of the given individual application. Several university studies in geodesy focus on the approach of high-accuracy positioning by means of single frequency receivers for static applications [e.g. GLABSCH et. al. 2009, SCHWIEGER and GLÄSER 2005, ALKAN 2010, REALINI et. al. 2010, KORTH and HOFMANN 2011]. Although intelligent approaches have been developed that compute a trajectory in the post-processing mode [REALINI et. al., 2010], at present, there are only a very few GNSS Low-Cost Systems that enable real-time processing. This approach to precise position determination by means of the computation of static raw data with single frequency receivers is currently being explored in a research project at the Beuth Hochschule für Technik Berlin - and is being further developed for kinematic applications. The project is embedded in the European Social Fund. It is a follow-up project in the area of
SLS Navigation Model-Based Design Approach
Oliver, T. Emerson; Anzalone, Evan; Geohagan, Kevin; Bernard, Bill; Park, Thomas
2018-01-01
management of design requirements to the development of usable models, model requirements, and model verification and validation efforts. The models themselves are represented in C/C++ code and accompanying data files. Under the idealized process, potential ambiguity in specification is reduced because the model must be implementable versus a requirement which is not necessarily subject to this constraint. Further, the models are shown to emulate the hardware during validation. For models developed by the Navigation Team, a common interface/standalone environment was developed. The common environment allows for easy implementation in design and analysis tools. Mechanisms such as unit test cases ensure implementation as the developer intended. The model verification and validation process provides a very high level of component design insight. The origin and implementation of the SLS variant of Model-based Design is described from the perspective of the SLS Navigation Team. The format of the models and the requirements are described. The Model-based Design approach has many benefits but is not without potential complications. Key lessons learned associated with the implementation of the Model Based Design approach and process from infancy to verification and certification are discussed
Future high precision experiments and new physics beyond Standard Model
International Nuclear Information System (INIS)
Luo, Mingxing.
1993-01-01
High precision (< 1%) electroweak experiments that have been done or are likely to be done in this decade are examined on the basis of Standard Model (SM) predictions of fourteen weak neutral current observables and fifteen W and Z properties to the one-loop level, the implications of the corresponding experimental measurements to various types of possible new physics that enter at the tree or loop level were investigated. Certain experiments appear to have special promise as probes of the new physics considered here
High precision measurements of 26Naβ- decay
Grinyer, G. F.; Svensson, C. E.; Andreoiu, C.; Andreyev, A. N.; Austin, R. A.; Ball, G. C.; Chakrawarthy, R. S.; Finlay, P.; Garrett, P. E.; Hackman, G.; Hardy, J. C.; Hyland, B.; Iacob, V. E.; Koopmans, K. A.; Kulp, W. D.; Leslie, J. R.; MacDonald, J. A.; Morton, A. C.; Ormand, W. E.; Osborne, C. J.; Pearson, C. J.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Scraggs, H. C.; Schwarzenberg, J.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Wood, J. L.; Zganjar, E. F.
2005-04-01
High-precision measurements of the half-life and β-branching ratios for the β- decay of 26Na to 26Mg have been measured in β-counting and γ-decay experiments, respectively. A 4π proportional counter and fast tape transport system were employed for the half-life measurement, whereas the γ rays emitted by the daughter nucleus 26Mg were detected with the 8π γ-ray spectrometer, both located at TRIUMF's isotope separator and accelerator radioactive beam facility. The half-life of 26Na was determined to be T1/2=1.07128±0.00013±0.00021s, where the first error is statistical and the second systematic. The logft values derived from these experiments are compared with theoretical values from a full sd-shell model calculation.
A clinical study of navigation accuracy during surgery
International Nuclear Information System (INIS)
Hirabayashi, Hidehiro; Uchiyama, Yoshitomo; Hoshida, Toru; Nakase, Hiroyuki; Morimoto, Tetsuya; Sakaki, Toshisuke
2000-01-01
It is essential to implement image-guided surgery or neuronavigation technologies that can be applied during functional surgery to localize targets accurately in the surgical field. Various navigation systems have been developed, such as the optical system and mechanical-arm-based system, to localize targets in the operative field. However, either the reference system, in optical systems, or the arm joint, in mechanical-arm-based systems, can sometimes interfere with surgical maneuvers. Therefore, we used the magnetic-force-based Computed Assisted Neurosurgery system (CANS system, Shimadzu, Co. Ltd., Kyoto, Japan) for neuronavigation. The purpose of this study was to evaluate the accuracy of the CANS navigation system. Ten patients with medically refractory epilepsy underwent implantation of subdural electrode grids to detect the epilepsy focus, and then lobectomy or multiple subpial transection was performed after informed consent was obtained. The male/female ratio was 6:4 and the mean age was 30.7 years. The CANS navigator system consists mainly of a magnetic source, a localizer probe with magnetic sensor, a three-dimensional locating measuring instrument (digitizer), an image scanner, and a personal computer. To determine the localization accuracy, the probe was moved on the subdural electrode grid which typically consists of 64 or 16 platinum-iridium electrode contacts (3 mm in the diameter) embedded in a Silastic sheet. The array of electrodes was 8 x 8 cm or 2 x 8 cm and the center-to-center inter-electrode distance was 10 mm. We evaluated the inter-electrode distances and spatial relationships among the electrodes to quantitate the precision of the probe tip localization and assumed the nasion origin reference system to assess the distribution of target coordinates. The measurement errors of each component derived from different planes for the same targets were evaluated in ten patients. The error in X-dimension ranged from 0.38 mm to 7.8 mm, the error in Y
2013-07-10
... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 105 [Docket No. USCG-2013-0397] RIN 1625-AC06 Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments; Correction AGENCY: Coast Guard, DHS. ACTION: Final rule; correction. SUMMARY: The Coast Guard published a final rule...
Yan, Peng; Zhang, Yangming
2018-06-01
High performance scanning of nano-manipulators is widely deployed in various precision engineering applications such as SPM (scanning probe microscope), where trajectory tracking of sophisticated reference signals is an challenging control problem. The situation is further complicated when rate dependent hysteresis of the piezoelectric actuators and the stress-stiffening induced nonlinear stiffness of the flexure mechanism are considered. In this paper, a novel control framework is proposed to achieve high precision tracking of a piezoelectric nano-manipulator subjected to hysteresis and stiffness nonlinearities. An adaptive parameterized rate-dependent Prandtl-Ishlinskii model is constructed and the corresponding adaptive inverse model based online compensation is derived. Meanwhile a robust adaptive control architecture is further introduced to improve the tracking accuracy and robustness of the compensated system, where the parametric uncertainties of the nonlinear dynamics can be well eliminated by on-line estimations. Comparative experimental studies of the proposed control algorithm are conducted on a PZT actuated nano-manipulating stage, where hysteresis modeling accuracy and excellent tracking performance are demonstrated in real-time implementations, with significant improvement over existing results.
Ding, Wenwu; Tan, Bingfeng; Chen, Yongchang; Teferle, Felix Norman; Yuan, Yunbin
2018-02-01
The performance of real-time (RT) precise positioning can be improved by utilizing observations from multiple Global Navigation Satellite Systems (GNSS) instead of one particular system. Since the end of 2012, BeiDou, independently established by China, began to provide operational services for users in the Asia-Pacific regions. In this study, a regional RT precise positioning system is developed to evaluate the performance of GPS/BeiDou observations in Australia in providing high precision positioning services for users. Fixing three hourly updated satellite orbits, RT correction messages are generated and broadcasted by processing RT observation/navigation data streams from the national network of GNSS Continuously Operating Reference Stations in Australia (AUSCORS) at the server side. At the user side, RT PPP is realized by processing RT data streams and the RT correction messages received. RT clock offsets, for which the accuracy reached 0.07 and 0.28 ns for GPS and BeiDou, respectively, can be determined. Based on these corrections, an accuracy of 12.2, 30.0 and 45.6 cm in the North, East and Up directions was achieved for the BeiDou-only solution after 30 min while the GPS-only solution reached 5.1, 15.3 and 15.5 cm for the same components at the same time. A further improvement of 43.7, 36.9 and 45.0 percent in the three directions, respectively, was achieved for the combined GPS/BeiDou solution. After the initialization process, the North, East and Up positioning accuracies were 5.2, 8.1 and 17.8 cm, respectively, for the BeiDou-only solution, while 1.5, 3.0, and 4.7 cm for the GPS-only solution. However, we only noticed a 20.9% improvement in the East direction was obtained for the GPS/BeiDou solution, while no improvements in the other directions were detected. It is expected that such improvements may become bigger with the increasing accuracy of the BeiDou-only solution.
Restricted Navigation Areas - USACE IENC
Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...
Sensitivity of Magnetospheric Multi-Scale (MMS) Mission Navigation Accuracy to Major Error Sources
Olson, Corwin; Long, Anne; Car[emter. Russell
2011-01-01
The Magnetospheric Multiscale (MMS) mission consists of four satellites flying in formation in highly elliptical orbits about the Earth, with a primary objective of studying magnetic reconnection. The baseline navigation concept is independent estimation of each spacecraft state using GPS pseudorange measurements referenced to an Ultra Stable Oscillator (USO) with accelerometer measurements included during maneuvers. MMS state estimation is performed onboard each spacecraft using the Goddard Enhanced Onboard Navigation System (GEONS), which is embedded in the Navigator GPS receiver. This paper describes the sensitivity of MMS navigation performance to two major error sources: USO clock errors and thrust acceleration knowledge errors.
NFC Internal: An Indoor Navigation System
Ozdenizci, Busra; Coskun, Vedat; Ok, Kerem
2015-01-01
Indoor navigation systems have recently become a popular research field due to the lack of GPS signals indoors. Several indoors navigation systems have already been proposed in order to eliminate deficiencies; however each of them has several technical and usability limitations. In this study, we propose NFC Internal, a Near Field Communication (NFC)-based indoor navigation system, which enables users to navigate through a building or a complex by enabling a simple location update, simply by touching NFC tags those are spread around and orient users to the destination. In this paper, we initially present the system requirements, give the design details and study the viability of NFC Internal with a prototype application and a case study. Moreover, we evaluate the performance of the system and compare it with existing indoor navigation systems. It is seen that NFC Internal has considerable advantages and significant contributions to existing indoor navigation systems in terms of security and privacy, cost, performance, robustness, complexity, user preference and commercial availability. PMID:25825976
Shu, Deming; Shvydko, Yuri; Stoupin, Stanislav A.; Khachatryan, Ruben; Goetze, Kurt A.; Roberts, Timothy
2015-04-14
A method and an ultrahigh-resolution spectrometer including a precision mechanical structure for positioning inelastic X-ray scattering optics are provided. The spectrometer includes an X-ray monochromator and an X-ray analyzer, each including X-ray optics of a collimating (C) crystal, a pair of dispersing (D) element crystals, anomalous transmission filter (F) and a wavelength (W) selector crystal. A respective precision mechanical structure is provided with the X-ray monochromator and the X-ray analyzer. The precision mechanical structure includes a base plate, such as an aluminum base plate; positioning stages for D-crystal alignment; positioning stages with an incline sensor for C/F/W-crystal alignment, and the positioning stages including flexure-based high-stiffness structure.
High-precision half-life determination for 21Na using a 4 π gas-proportional counter
Finlay, P.; Laffoley, A. T.; Ball, G. C.; Bender, P. C.; Dunlop, M. R.; Dunlop, R.; Hackman, G.; Leslie, J. R.; MacLean, A. D.; Miller, D.; Moukaddam, M.; Olaizola, B.; Severijns, N.; Smith, J. K.; Southall, D.; Svensson, C. E.
2017-08-01
A high-precision half-life measurement for the superallowed β+ transition between the isospin T =1 /2 mirror nuclei 21Na and 21Ne has been performed at the TRIUMF-ISAC radioactive ion beam facility yielding T1 /2=22.4506 (33 ) s, a result that is a factor of 4 more precise than the previous world-average half-life for 21Na and represents the single most precisely determined half-life for a transition between mirror nuclei to date. The contribution to the uncertainty in the 21Na F tmirror value due to the half-life is now reduced to the level of the nuclear-structure-dependent theoretical corrections, leaving the branching ratio as the dominant experimental uncertainty.
A novel approach for high precision rapid potentiometric titrations: application to hydrazine assay.
Sahoo, P; Malathi, N; Ananthanarayanan, R; Praveen, K; Murali, N
2011-11-01
We propose a high precision rapid personal computer (PC) based potentiometric titration technique using a specially designed mini-cell to carry out redox titrations for assay of chemicals in quality control laboratories attached to industrial, R&D, and nuclear establishments. Using this technique a few microlitre of sample (50-100 μl) in a total volume of ~2 ml solution can be titrated and the waste generated after titration is extremely low comparing to that obtained from the conventional titration technique. The entire titration including online data acquisition followed by immediate offline analysis of data to get information about concentration of unknown sample is completed within a couple of minutes (about 2 min). This facility has been created using a new class of sensors, viz., pulsating sensors developed in-house. The basic concept in designing such instrument and the salient features of the titration device are presented in this paper. The performance of the titration facility was examined by conducting some of the high resolution redox titrations using dilute solutions--hydrazine against KIO(3) in HCl medium, Fe(II) against Ce(IV) and uranium using Davies-Gray method. The precision of titrations using this innovative approach lies between 0.048% and 1.0% relative standard deviation in different redox titrations. With the evolution of this rapid PC based titrator it was possible to develop a simple but high precision potentiometric titration technique for quick determination of hydrazine in nuclear fuel dissolver solution in the context of reprocessing of spent nuclear fuel in fast breeder reactors. © 2011 American Institute of Physics
High-Precision Phenotyping of Grape Bunch Architecture Using Fast 3D Sensor and Automation.
Rist, Florian; Herzog, Katja; Mack, Jenny; Richter, Robert; Steinhage, Volker; Töpfer, Reinhard
2018-03-02
Wine growers prefer cultivars with looser bunch architecture because of the decreased risk for bunch rot. As a consequence, grapevine breeders have to select seedlings and new cultivars with regard to appropriate bunch traits. Bunch architecture is a mosaic of different single traits which makes phenotyping labor-intensive and time-consuming. In the present study, a fast and high-precision phenotyping pipeline was developed. The optical sensor Artec Spider 3D scanner (Artec 3D, L-1466, Luxembourg) was used to generate dense 3D point clouds of grapevine bunches under lab conditions and an automated analysis software called 3D-Bunch-Tool was developed to extract different single 3D bunch traits, i.e., the number of berries, berry diameter, single berry volume, total volume of berries, convex hull volume of grapes, bunch width and bunch length. The method was validated on whole bunches of different grapevine cultivars and phenotypic variable breeding material. Reliable phenotypic data were obtained which show high significant correlations (up to r² = 0.95 for berry number) compared to ground truth data. Moreover, it was shown that the Artec Spider can be used directly in the field where achieved data show comparable precision with regard to the lab application. This non-invasive and non-contact field application facilitates the first high-precision phenotyping pipeline based on 3D bunch traits in large plant sets.
2010-08-11
... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Parts 3 and 165 [Docket No. USCG-2010-0351] RIN 1625-ZA25 Navigation and Navigable Waters; Technical, Organizational, and Conforming Amendments, Sector Columbia River, WA AGENCY: Coast Guard, DHS. ACTION: Final rule. SUMMARY: This rule makes non-substantive...
Sex differences in navigation strategy and efficiency.
Boone, Alexander P; Gong, Xinyi; Hegarty, Mary
2018-05-22
Research on human navigation has indicated that males and females differ in self-reported navigation strategy as well as objective measures of navigation efficiency. In two experiments, we investigated sex differences in navigation strategy and efficiency using an objective measure of strategy, the dual-solution paradigm (DSP; Marchette, Bakker, & Shelton, 2011). Although navigation by shortcuts and learned routes were the primary strategies used in both experiments, as in previous research on the DSP, individuals also utilized route reversals and sometimes found the goal location as a result of wandering. Importantly, sex differences were found in measures of both route selection and navigation efficiency. In particular, males were more likely to take shortcuts and reached their goal location faster than females, while females were more likely to follow learned routes and wander. Self-report measures of strategy were only weakly correlated with objective measures of strategy, casting doubt on their usefulness. This research indicates that the sex difference in navigation efficiency is large, and only partially related to an individual's navigation strategy as measured by the dual-solution paradigm.
Celestial Navigation in the USA, Fiji, and Tunisia
Holbrook, Jarita C.
2015-05-01
Today there are many coastal communities that are home to navigators who use stars for position finding at night; I was, however, unaware of this fact when I began researching celestial navigation practices in 1997. My project focused on three communities: the Moce Islanders of Fiji, the Kerkennah Islanders in Tunisia, and the U.S. Navy officers and students at the United States Naval Academy, Annapolis, Maryland. My goal was to answer the question of why people continue to navigate by the stars, but also to understand the role of technology in their navigation practices. Using anthropology techniques of ethnography including participant observation, formal and informal interviews, audio and videotaping, I gathered data over five years at the three communities. I began by learning the details of how they use the stars for navigation. Next, I learned about who did the navigation and where they learned to navigate. I gathered opinions on various navigation aids and instruments, and opinions about the future of using the stars for navigation. I listened to the stories that they told about navigating. In the United States I worked in English, in Fiji, in Fijian and English, and in Tunisia, French and English. For the formal interviews I worked with translators. The navigators use stars for navigating today but the future of their techniques is not certain. Though practiced today, these celestial navigation traditions have undergone and continue to undergo changes. New navigational technologies are part of the stimulation for change, thus 'a meeting of different worlds' is symbolized by peoples encounters with these technologies.
Nautical Navigation Aids (NAVAID) Locations
Department of Homeland Security — Structures intended to assist a navigator to determine position or safe course, or to warn of dangers or obstructions to navigation. This dataset includes lights,...
High precision Standard Model Physics
International Nuclear Information System (INIS)
Magnin, J.
2009-01-01
The main goal of the LHCb experiment, one of the four large experiments of the Large Hadron Collider, is to try to give answers to the question of why Nature prefers matter over antimatter? This will be done by studying the decay of b quarks and their antimatter partners, b-bar, which will be produced by billions in 14 TeV p-p collisions by the LHC. In addition, as 'beauty' particles mainly decay in charm particles, an interesting program of charm physics will be carried on, allowing to measure quantities as for instance the D 0 -D-bar 0 mixing, with incredible precision.
High-precision soft x-ray polarimeter at Diamond Light Source.
Wang, H; Dhesi, S S; Maccherozzi, F; Cavill, S; Shepherd, E; Yuan, F; Deshmukh, R; Scott, S; van der Laan, G; Sawhney, K J S
2011-12-01
The development and performance of a high-precision polarimeter for the polarization analysis in the soft x-ray region is presented. This versatile, high-vacuum compatible instrument is supported on a hexapod to simplify the alignment with a resolution less than 5 μrad, and can be moved with its own independent control system easily between different beamlines and synchrotron facilities. The polarimeter can also be used for the characterization of reflection and transmission properties of optical elements. A W/B(4)C multilayer phase retarder was used to characterize the polarization state up to 1200 eV. A fast and accurate alignment procedure was developed, and complete polarization analysis of the APPLE II undulator at 712 eV has been performed.
Energy Technology Data Exchange (ETDEWEB)
El-Khoury, P
1998-04-15
The study of exotic atoms, in which an orbiting electron of a normal atom is replaced by a negatively charged particle ({pi}{sup -}, {mu}{sup -}, p, {kappa}{sup -}, {sigma}{sup -},...) may provide information on the orbiting particle and the atomic nucleus, as well as on their interaction. In this work, we were interested in pionic atoms ({pi}{sup -14} N) on the one hand in order to determine the pion mass with high accuracy (4 ppm), and on the other hand in antiprotonic atoms (pp-bar) in order to study the strong nucleon-antinucleon interaction at threshold. In this respect, a high-resolution crystal spectrometer was coupled to a cyclotron trap which provides a high stop density for particles in gas targets at low pressure. Using curved crystals, an extended X-ray source could be imaged onto the detector. Charge-Coupled Devices were used as position sensitive detectors in order to measure the Bragg angle of the transition to a high precision. The use of gas targets resolved the ambiguity owing to the number of K electrons for the value of the pion mass, and, for the first time, strong interaction shift and broadening of the 2p level in antiprotonic hydrogen were measured directly. (author)
An on-line monitoring system for navigation equipment
Wang, Bo; Yang, Ping; Liu, Jing; Yang, Zhengbo; Liang, Fei
2017-10-01
Civil air navigation equipment is the most important infrastructure of Civil Aviation, which is closely related to flight safety. In addition to regular flight inspection, navigation equipment's patrol measuring, maintenance measuring, running measuring under special weather conditions are the important means of ensuring aviation flight safety. According to the safety maintenance requirements of Civil Aviation Air Traffic Control navigation equipment, this paper developed one on-line monitoring system with independent intellectual property rights for navigation equipment, the system breakthroughs the key technologies of measuring navigation equipment on-line including Instrument Landing System (ILS) and VHF Omni-directional Range (VOR), which also meets the requirements of navigation equipment ground measurement set by the ICAO DOC 8071, it provides technical means of the ground on-line measurement for navigation equipment, improves the safety of navigation equipment operation, and reduces the impact of measuring navigation equipment on airport operation.
Improving BeiDou precise orbit determination using observations of onboard MEO satellite receivers
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.
Száz, Dénes; Farkas, Alexandra; Barta, András; Kretzer, Balázs; Blahó, Miklós; Egri, Ádám; Szabó, Gyula; Horváth, Gábor
2017-09-01
skies, the sky-polarimetric navigation is more accurate, but at low solar elevations its accuracy remains relatively large even at high cloudiness. For a given ρ, the absolute value of averaged peak North uncertainties dramatically decreases with increasing θ until the sign (±) change of these uncertainties. For a given θ, this absolute value can either decrease or increase with increasing ρ. The most advantageous sky situations for this navigation method are at summer solstice when the solar elevation and cloudiness are 35° ≤ θ ≤ 40° and 2 oktas ≤ ρ ≤ 3 oktas.
Microsurgery robots: addressing the needs of high-precision surgical interventions.
Mattos, Leonardo S; Caldwell, Darwin G; Peretti, Giorgio; Mora, Francesco; Guastini, Luca; Cingolani, Roberto
2016-01-01
Robotics has a significant potential to enhance the overall capacity and efficiency of healthcare systems. Robots can help surgeons perform better quality operations, leading to reductions in the hospitalisation time of patients and in the impact of surgery on their postoperative quality of life. In particular, robotics can have a significant impact on microsurgery, which presents stringent requirements for superhuman precision and control of the surgical tools. Microsurgery is, in fact, expected to gain importance in a growing range of surgical specialties as novel technologies progressively enable the detection, diagnosis and treatment of diseases at earlier stages. Within such scenarios, robotic microsurgery emerges as one of the key components of future surgical interventions, and will be a vital technology for addressing major surgical challenges. Nonetheless, several issues have yet to be overcome in terms of mechatronics, perception and surgeon-robot interfaces before microsurgical robots can achieve their full potential in operating rooms. Research in this direction is progressing quickly and microsurgery robot prototypes are gradually demonstrating significant clinical benefits in challenging applications such as reconstructive plastic surgery, ophthalmology, otology and laryngology. These are reassuring results offering confidence in a brighter future for high-precision surgical interventions.
32 CFR 644.3 - Navigation Projects.
2010-07-01
... 32 National Defense 4 2010-07-01 2010-07-01 true Navigation Projects. 644.3 Section 644.3 National... HANDBOOK Project Planning Civil Works § 644.3 Navigation Projects. (a) Land to be acquired in fee. All... construction and borrow areas. (3) In navigation-only projects, the right to permanently flood should be...
A 3D Model Based Imdoor Navigation System for Hubei Provincial Museum
Xu, W.; Kruminaite, M.; Onrust, B.; Liu, H.; Xiong, Q.; Zlatanova, S.
2013-11-01
3D models are more powerful than 2D maps for indoor navigation in a complicate space like Hubei Provincial Museum because they can provide accurate descriptions of locations of indoor objects (e.g., doors, windows, tables) and context information of these objects. In addition, the 3D model is the preferred navigation environment by the user according to the survey. Therefore a 3D model based indoor navigation system is developed for Hubei Provincial Museum to guide the visitors of museum. The system consists of three layers: application, web service and navigation, which is built to support localization, navigation and visualization functions of the system. There are three main strengths of this system: it stores all data needed in one database and processes most calculations on the webserver which make the mobile client very lightweight, the network used for navigation is extracted semi-automatically and renewable, the graphic user interface (GUI), which is based on a game engine, has high performance of visualizing 3D model on a mobile display.
Brandriss, Mark E.
2010-01-01
This article describes ways to incorporate high-precision measurements of the specific gravities of minerals into undergraduate courses in mineralogy and physical geology. Most traditional undergraduate laboratory methods of measuring specific gravity are suitable only for unusually large samples, which severely limits their usefulness for student…
Low-cost precise measurement of oscillator frequency instability based on GNSS carrier observation
Kou, Yanhong; Jiao, Yue; Xu, Dongyang; Zhang, Meng; Liu, Ya; Li, Xiaohui
2013-03-01
Global navigation satellite systems (GNSS) receivers can be used in time and frequency metrology by exploiting stable GNSS time scales. This paper proposes a low-cost method for precise measurement of oscillator frequency instability using a single-frequency software GNSS receiver. The only required hardware is a common radio frequency (RF) data collection device driven by the oscillator under test (OUT). The receiver solves the oscillator frequency error in high time resolution using the carrier Doppler observation and the broadcast ephemeris from one of the available satellites employing the onboard reference atomic frequency standard that is more stable than the OUT. Considering the non-stable and non-Gaussian properties of the frequency error measurement, an unbiased finite impulse response (FIR) filter is employed to obtain robust estimation and filter out measurement noise. The effects of different filter orders and convolution lengths are further discussed. The frequency error of an oven controlled oscillator (OCXO) is measured using live Beidou-2/Compass signals. The results are compared with the synchronous measurement using a specialized phase comparator with the standard coordinated universal time (UTC) signal from the master clock H226 in the national time service center (NTSC) of China as its reference. The Allan deviation (ADEV) estimates using the two methods have a 99.9% correlation coefficient and a 0.6% mean relative difference over 1-1000 s intervals. The experiment demonstrates the effectiveness and high precision of the software receiver method.
2010-01-01
... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Communication and navigation equipment for... § 121.349 Communication and navigation equipment for operations under VFR over routes not navigated by... receiver providing visual and aural signals; and (iii) One ILS receiver; and (3) Any RNAV system used to...
Initial assessment of the COMPASS/BeiDou-3: new-generation navigation signals
Zhang, Xiaohong; Wu, Mingkui; Liu, Wanke; Li, Xingxing; Yu, Shun; Lu, Cuixian; Wickert, Jens
2017-10-01
The successful launch of five new-generation experimental satellites of the China's BeiDou Navigation Satellite System, namely BeiDou I1-S, I2-S, M1-S, M2-S, and M3-S, marks a significant step in expanding BeiDou into a navigation system with global coverage. In addition to B1I (1561.098 MHz) and B3I (1269.520 MHz) signals, the new-generation BeiDou-3 experimental satellites are also capable of transmitting several new navigation signals in space, namely B1C at 1575.42 MHz, B2a at 1176.45 MHz, and B2b at 1207.14 MHz. For the first time, we present an initial characterization and performance assessment for these new-generation BeiDou-3 satellites and their signals. The L1/L2/L5 signals from GPS Block IIF satellites, E1/E5a/E5b signals from Galileo satellites, and B1I/B2I/B3I signals from BeiDou-2 satellites are also evaluated for comparison. The characteristics of the B1C, B1I, B2a, B2b, and B3I signals are evaluated in terms of observed carrier-to-noise density ratio, pseudorange multipath and noise, triple-frequency carrier-phase ionosphere-free and geometry-free combination, and double-differenced carrier-phase and code residuals. The results demonstrate that the observational quality of the new-generation BeiDou-3 signals is comparable to that of GPS L1/L2/L5 and Galileo E1/E5a/E5b signals. However, the analysis of code multipath shows that the elevation-dependent code biases, which have been previously identified to exist in the code observations of the BeiDou-2 satellites, seem to be not obvious for all the available signals of the new-generation BeiDou-3 satellites. This will significantly benefit precise applications that resolve wide-lane ambiguity based on Hatch-Melbourne-Wübbena linear combinations and other applications such as single-frequency precise point positioning (PPP) based on the ionosphere-free code-carrier combinations. Furthermore, with regard to the triple-frequency carrier-phase ionosphere-free and geometry-free combination, it is found
Autonomous Robot Navigation based on Visual Landmarks
DEFF Research Database (Denmark)
Livatino, Salvatore
2005-01-01
The use of landmarks for robot navigation is a popular alternative to having a geometrical model of the environment through which to navigate and monitor self-localization. If the landmarks are defined as special visual structures already in the environment then we have the possibility of fully a...... automatically learn and store visual landmarks, and later recognize these landmarks from arbitrary positions and thus estimate robot position and heading.......The use of landmarks for robot navigation is a popular alternative to having a geometrical model of the environment through which to navigate and monitor self-localization. If the landmarks are defined as special visual structures already in the environment then we have the possibility of fully...... autonomous navigation and self-localization using automatically selected landmarks. The thesis investigates autonomous robot navigation and proposes a new method which benefits from the potential of the visual sensor to provide accuracy and reliability to the navigation process while relying on naturally...
A high precision semi-analytic mass function
Energy Technology Data Exchange (ETDEWEB)
Del Popolo, Antonino [Dipartimento di Fisica e Astronomia, University of Catania, Viale Andrea Doria 6, I-95125 Catania (Italy); Pace, Francesco [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL (United Kingdom); Le Delliou, Morgan, E-mail: adelpopolo@oact.inaf.it, E-mail: francesco.pace@manchester.ac.uk, E-mail: delliou@ift.unesp.br [Instituto de Física Teorica, Universidade Estadual de São Paulo (IFT-UNESP), Rua Dr. Bento Teobaldo Ferraz 271, Bloco 2—Barra Funda, 01140-070 São Paulo, SP Brazil (Brazil)
2017-03-01
In this paper, extending past works of Del Popolo, we show how a high precision mass function (MF) can be obtained using the excursion set approach and an improved barrier taking implicitly into account a non-zero cosmological constant, the angular momentum acquired by tidal interaction of proto-structures and dynamical friction. In the case of the ΛCDM paradigm, we find that our MF is in agreement at the 3% level to Klypin's Bolshoi simulation, in the mass range M {sub vir} = 5 × 10{sup 9} h {sup −1} M {sub ⊙}–−5 × 10{sup 14} h {sup −1} M {sub ⊙} and redshift range 0 ∼< z ∼< 10. For z = 0 we also compared our MF to several fitting formulae, and found in particular agreement with Bhattacharya's within 3% in the mass range 10{sup 12}–10{sup 16} h {sup −1} M {sub ⊙}. Moreover, we discuss our MF validity for different cosmologies.
NFC Internal: An Indoor Navigation System
Directory of Open Access Journals (Sweden)
Busra Ozdenizci
2015-03-01
Full Text Available Indoor navigation systems have recently become a popular research field due to the lack of GPS signals indoors. Several indoors navigation systems have already been proposed in order to eliminate deficiencies; however each of them has several technical and usability limitations. In this study, we propose NFC Internal, a Near Field Communication (NFC-based indoor navigation system, which enables users to navigate through a building or a complex by enabling a simple location update, simply by touching NFC tags those are spread around and orient users to the destination. In this paper, we initially present the system requirements, give the design details and study the viability of NFC Internal with a prototype application and a case study. Moreover, we evaluate the performance of the system and compare it with existing indoor navigation systems. It is seen that NFC Internal has considerable advantages and significant contributions to existing indoor navigation systems in terms of security and privacy, cost, performance, robustness, complexity, user preference and commercial availability.
Convolutional Neural Network-Based Robot Navigation Using Uncalibrated Spherical Images.
Ran, Lingyan; Zhang, Yanning; Zhang, Qilin; Yang, Tao
2017-06-12
Vision-based mobile robot navigation is a vibrant area of research with numerous algorithms having been developed, the vast majority of which either belong to the scene-oriented simultaneous localization and mapping (SLAM) or fall into the category of robot-oriented lane-detection/trajectory tracking. These methods suffer from high computational cost and require stringent labelling and calibration efforts. To address these challenges, this paper proposes a lightweight robot navigation framework based purely on uncalibrated spherical images. To simplify the orientation estimation, path prediction and improve computational efficiency, the navigation problem is decomposed into a series of classification tasks. To mitigate the adverse effects of insufficient negative samples in the "navigation via classification" task, we introduce the spherical camera for scene capturing, which enables 360° fisheye panorama as training samples and generation of sufficient positive and negative heading directions. The classification is implemented as an end-to-end Convolutional Neural Network (CNN), trained on our proposed Spherical-Navi image dataset, whose category labels can be efficiently collected. This CNN is capable of predicting potential path directions with high confidence levels based on a single, uncalibrated spherical image. Experimental results demonstrate that the proposed framework outperforms competing ones in realistic applications.
Convolutional Neural Network-Based Robot Navigation Using Uncalibrated Spherical Images
Directory of Open Access Journals (Sweden)
Lingyan Ran
2017-06-01
Full Text Available Vision-based mobile robot navigation is a vibrant area of research with numerous algorithms having been developed, the vast majority of which either belong to the scene-oriented simultaneous localization and mapping (SLAM or fall into the category of robot-oriented lane-detection/trajectory tracking. These methods suffer from high computational cost and require stringent labelling and calibration efforts. To address these challenges, this paper proposes a lightweight robot navigation framework based purely on uncalibrated spherical images. To simplify the orientation estimation, path prediction and improve computational efficiency, the navigation problem is decomposed into a series of classification tasks. To mitigate the adverse effects of insufficient negative samples in the “navigation via classification” task, we introduce the spherical camera for scene capturing, which enables 360° fisheye panorama as training samples and generation of sufficient positive and negative heading directions. The classification is implemented as an end-to-end Convolutional Neural Network (CNN, trained on our proposed Spherical-Navi image dataset, whose category labels can be efficiently collected. This CNN is capable of predicting potential path directions with high confidence levels based on a single, uncalibrated spherical image. Experimental results demonstrate that the proposed framework outperforms competing ones in realistic applications.
Precision electron polarimetry
International Nuclear Information System (INIS)
Chudakov, E.
2013-01-01
A new generation of precise Parity-Violating experiments will require a sub-percent accuracy of electron beam polarimetry. Compton polarimetry can provide such accuracy at high energies, but at a few hundred MeV the small analyzing power limits the sensitivity. Mo/ller polarimetry provides a high analyzing power independent on the beam energy, but is limited by the properties of the polarized targets commonly used. Options for precision polarimetry at 300 MeV will be discussed, in particular a proposal to use ultra-cold atomic hydrogen traps to provide a 100%-polarized electron target for Mo/ller polarimetry
Wang, Huixiang; Wang, Fang; Leong, Anthony Peng Yew; Xu, Lu; Chen, Xiaojun; Wang, Qiugen
2016-09-01
Augmented reality (AR) enables superimposition of virtual images onto the real world. The aim of this study is to present a novel AR-based navigation system for sacroiliac screw insertion and to evaluate its feasibility and accuracy in cadaveric experiments. Six cadavers with intact pelvises were employed in our study. They were CT scanned and the pelvis and vessels were segmented into 3D models. The ideal trajectory of the sacroiliac screw was planned and represented visually as a cylinder. For the intervention, the head mounted display created a real-time AR environment by superimposing the virtual 3D models onto the surgeon's field of view. The screws were drilled into the pelvis as guided by the trajectory represented by the cylinder. Following the intervention, a repeat CT scan was performed to evaluate the accuracy of the system, by assessing the screw positions and the deviations between the planned trajectories and inserted screws. Post-operative CT images showed that all 12 screws were correctly placed with no perforation. The mean deviation between the planned trajectories and the inserted screws was 2.7 ± 1.2 mm at the bony entry point, 3.7 ± 1.1 mm at the screw tip, and the mean angular deviation between the two trajectories was 2.9° ± 1.1°. The mean deviation at the nerve root tunnels region on the sagittal plane was 3.6 ± 1.0 mm. This study suggests an intuitive approach for guiding screw placement by way of AR-based navigation. This approach was feasible and accurate. It may serve as a valuable tool for assisting percutaneous sacroiliac screw insertion in live surgery.
Inland Electronic Navigational Charts (IENC)
Army Corps of Engineers, Department of the Army, Department of Defense — These Inland Electronic Navigational Charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...
International Nuclear Information System (INIS)
Dobiasch, S.; Kampfer, S.; Burkhardt, R.; Wilkens, J.J.; Schilling, D.; Schmid, T.E.; Combs, S.E.
2017-01-01
High-precision radiotherapy (RT) requires precise positioning, particularly with high single doses. Fiducial markers in combination with onboard imaging are excellent tools to support this. The purpose of this study is to establish a pancreatic cancer mouse model for high-precision image-guided RT (IGRT) using the liquid fiducial marker BioXmark (Nanovi, Kongens Lyngby, Denmark). In an animal-based cancer model, different volumes of BioXmark (10-50 μl), application forms, and imaging modalities - cone-beam computer tomography (CBCT) incorporated in either the Small Animal Radiation Research Platform (SARRP) or the small-animal micro-CT Scanner (SkyScan; Bruker, Brussels, Belgium) - as well as subsequent RT with the SARRP system were analyzed to derive recommendations for BioXmark. Even small volumes (10 μl) of BioXmark could be detected by CBCT (SARRP and Skyscan). Larger volumes (50 μl) led to hardening artefacts. The position of BioXmark was monitored at least weekly by CBCT and was stable over 4 months. BioXmark was shown to be well tolerated; no changes in physical condition or toxic side effects were observed in comparison to control mice. BioXmark enabled an exact fusion with the original treatment plan with less hardening artefacts, and minimized the application of contrast agent for fractionated RT. An orthotopic pancreatic tumor mouse model was established for high-precision IGRT using a fiducial marker. BioXmark was successfully tested and provides the perfect basis for improved imaging in high-precision RT. BioXmark enables a unique application method and optimal targeted precision in fractionated RT. Therefore, preclinical trials evaluating novel fractionation regimens and/or combination treatment with high-end RT can be performed. (orig.) [de
High-precision photometry by telescope defocusing - I. The transiting planetary system WASP-5
DEFF Research Database (Denmark)
Southworth, J.; Hinse, T. C.; Jørgensen, U. G.
2009-01-01
We present high-precision photometry of two transit events of the extrasolar planetary system WASP-5, obtained with the Danish 1.54-m telescope at European Southern Obseratory La Silla. In order to minimize both random and flat-fielding errors, we defocused the telescope so its point spread...
Deep sea AUV navigation using multiple acoustic beacons
Ji, Da-xiong; Song, Wei; Zhao, Hong-yu; Liu, Jian
2016-04-01
Navigation is a critical requirement for the operation of Autonomous Underwater Vehicles (AUVs). To estimate the vehicle position, we present an algorithm using an extended Kalman filter (EKF) to integrate dead-reckoning position with acoustic ranges from multiple beacons pre-deployed in the operating environment. Owing to high latency, variable sound speed multipath transmissions and unreliability in acoustic measurements, outlier recognition techniques are proposed as well. The navigation algorithm has been tested by the recorded data of deep sea AUV during field operations in a variety of environments. Our results show the improved performance over prior techniques based on position computation.
High Throughput, High Precision Hot Testing Tool for HBLED Wafer Level Testing
Energy Technology Data Exchange (ETDEWEB)
Solarz, Richard [KLA-Tencor Corporation, Milpitas, CA (United States); McCord, Mark [KLA-Tencor Corporation, Milpitas, CA (United States)
2015-12-31
The Socrates research effort developed an in depth understanding and demonstrated in a prototype tool new precise methods for teh characterization of color characteristics and flux from individual LEDs for the production of uniform quality lighting. This effort was focused on improving the color quality and consistency of solid state lighting and potentially reducing characterization costs for all LED product types. The patented laser hot testing method was demonstrated to be far more accurate than all current state of the art color and flux characterization methods in use by the solid state lighting industry today. A seperately patented LED grouping method (statistical binning) was demonstrated to be a useful approach to improving utilization of entire lots of large color and flux distributions of manufactured LEDs for high quality color solid-state lighting. At the conclusion of the research in late 2015 the solid-state lighting industry was however generally satisfied with its existing production methods for high quality color products for the small segment of customers that demand it, albeit with added costs.
Low Cost Integrated Navigation System for Unmanned Vessel
Directory of Open Access Journals (Sweden)
Yang Changsong
2017-11-01
Full Text Available Large errors of low-cost MEMS inertial measurement unit (MIMU lead to huge navigation errors, even wrong navigation information. An integrated navigation system for unmanned vessel is proposed. It consists of a low-cost MIMU and Doppler velocity sonar (DVS. This paper presents an integrated navigation method, to improve the performance of navigation system. The integrated navigation system is tested using simulation and semi-physical simulation experiments, whose results show that attitude, velocity and position accuracy has improved awfully, giving exactly accurate navigation results. By means of the combination of low-cost MIMU and DVS, the proposed system is able to overcome fast drift problems of the low cost IMU.
International Nuclear Information System (INIS)
Schorb, Martin; Briggs, John A.G.
2014-01-01
Performing fluorescence microscopy and electron microscopy on the same sample allows fluorescent signals to be used to identify and locate features of interest for subsequent imaging by electron microscopy. To carry out such correlative microscopy on vitrified samples appropriate for structural cryo-electron microscopy it is necessary to perform fluorescence microscopy at liquid-nitrogen temperatures. Here we describe an adaptation of a cryo-light microscopy stage to permit use of high-numerical aperture objectives. This allows high-sensitivity and high-resolution fluorescence microscopy of vitrified samples. We describe and apply a correlative cryo-fluorescence and cryo-electron microscopy workflow together with a fiducial bead-based image correlation procedure. This procedure allows us to locate fluorescent bacteriophages in cryo-electron microscopy images with an accuracy on the order of 50 nm, based on their fluorescent signal. It will allow the user to precisely and unambiguously identify and locate objects and events for subsequent high-resolution structural study, based on fluorescent signals. - Highlights: • Workflow for correlated cryo-fluorescence and cryo-electron microscopy. • Cryo-fluorescence microscopy setup incorporating a high numerical aperture objective. • Fluorescent signals located in cryo-electron micrographs with 50 nm spatial precision
Energy Technology Data Exchange (ETDEWEB)
Schorb, Martin [Structural and Computational Biology Unit, European Molecular Biology Laboratory, D-69117 Heidelberg (Germany); Briggs, John A.G., E-mail: john.briggs@embl.de [Structural and Computational Biology Unit, European Molecular Biology Laboratory, D-69117 Heidelberg (Germany); Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, D-69117 Heidelberg (Germany)
2014-08-01
Performing fluorescence microscopy and electron microscopy on the same sample allows fluorescent signals to be used to identify and locate features of interest for subsequent imaging by electron microscopy. To carry out such correlative microscopy on vitrified samples appropriate for structural cryo-electron microscopy it is necessary to perform fluorescence microscopy at liquid-nitrogen temperatures. Here we describe an adaptation of a cryo-light microscopy stage to permit use of high-numerical aperture objectives. This allows high-sensitivity and high-resolution fluorescence microscopy of vitrified samples. We describe and apply a correlative cryo-fluorescence and cryo-electron microscopy workflow together with a fiducial bead-based image correlation procedure. This procedure allows us to locate fluorescent bacteriophages in cryo-electron microscopy images with an accuracy on the order of 50 nm, based on their fluorescent signal. It will allow the user to precisely and unambiguously identify and locate objects and events for subsequent high-resolution structural study, based on fluorescent signals. - Highlights: • Workflow for correlated cryo-fluorescence and cryo-electron microscopy. • Cryo-fluorescence microscopy setup incorporating a high numerical aperture objective. • Fluorescent signals located in cryo-electron micrographs with 50 nm spatial precision.
High precision anatomy for MEG☆
Troebinger, Luzia; López, José David; Lutti, Antoine; Bradbury, David; Bestmann, Sven; Barnes, Gareth
2014-01-01
Precise MEG estimates of neuronal current flow are undermined by uncertain knowledge of the head location with respect to the MEG sensors. This is either due to head movements within the scanning session or systematic errors in co-registration to anatomy. Here we show how such errors can be minimized using subject-specific head-casts produced using 3D printing technology. The casts fit the scalp of the subject internally and the inside of the MEG dewar externally, reducing within session and between session head movements. Systematic errors in matching to MRI coordinate system are also reduced through the use of MRI-visible fiducial markers placed on the same cast. Bootstrap estimates of absolute co-registration error were of the order of 1 mm. Estimates of relative co-registration error were < 1.5 mm between sessions. We corroborated these scalp based estimates by looking at the MEG data recorded over a 6 month period. We found that the between session sensor variability of the subject's evoked response was of the order of the within session noise, showing no appreciable noise due to between-session movement. Simulations suggest that the between-session sensor level amplitude SNR improved by a factor of 5 over conventional strategies. We show that at this level of coregistration accuracy there is strong evidence for anatomical models based on the individual rather than canonical anatomy; but that this advantage disappears for errors of greater than 5 mm. This work paves the way for source reconstruction methods which can exploit very high SNR signals and accurate anatomical models; and also significantly increases the sensitivity of longitudinal studies with MEG. PMID:23911673
Development of a force-reflecting robotic platform for cardiac catheter navigation.
Park, Jun Woo; Choi, Jaesoon; Pak, Hui-Nam; Song, Seung Joon; Lee, Jung Chan; Park, Yongdoo; Shin, Seung Min; Sun, Kyung
2010-11-01
Electrophysiological catheters are used for both diagnostics and clinical intervention. To facilitate more accurate and precise catheter navigation, robotic cardiac catheter navigation systems have been developed and commercialized. The authors have developed a novel force-reflecting robotic catheter navigation system. The system is a network-based master-slave configuration having a 3-degree of freedom robotic manipulator for operation with a conventional cardiac ablation catheter. The master manipulator implements a haptic user interface device with force feedback using a force or torque signal either measured with a sensor or estimated from the motor current signal in the slave manipulator. The slave manipulator is a robotic motion control platform on which the cardiac ablation catheter is mounted. The catheter motions-forward and backward movements, rolling, and catheter tip bending-are controlled by electromechanical actuators located in the slave manipulator. The control software runs on a real-time operating system-based workstation and implements the master/slave motion synchronization control of the robot system. The master/slave motion synchronization response was assessed with step, sinusoidal, and arbitrarily varying motion commands, and showed satisfactory performance with insignificant steady-state motion error. The current system successfully implemented the motion control function and will undergo safety and performance evaluation by means of animal experiments. Further studies on the force feedback control algorithm and on an active motion catheter with an embedded actuation mechanism are underway. © 2010, Copyright the Authors. Artificial Organs © 2010, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.
High-Precision Phenotyping of Grape Bunch Architecture Using Fast 3D Sensor and Automation
Directory of Open Access Journals (Sweden)
Florian Rist
2018-03-01
Full Text Available Wine growers prefer cultivars with looser bunch architecture because of the decreased risk for bunch rot. As a consequence, grapevine breeders have to select seedlings and new cultivars with regard to appropriate bunch traits. Bunch architecture is a mosaic of different single traits which makes phenotyping labor-intensive and time-consuming. In the present study, a fast and high-precision phenotyping pipeline was developed. The optical sensor Artec Spider 3D scanner (Artec 3D, L-1466, Luxembourg was used to generate dense 3D point clouds of grapevine bunches under lab conditions and an automated analysis software called 3D-Bunch-Tool was developed to extract different single 3D bunch traits, i.e., the number of berries, berry diameter, single berry volume, total volume of berries, convex hull volume of grapes, bunch width and bunch length. The method was validated on whole bunches of different grapevine cultivars and phenotypic variable breeding material. Reliable phenotypic data were obtained which show high significant correlations (up to r2 = 0.95 for berry number compared to ground truth data. Moreover, it was shown that the Artec Spider can be used directly in the field where achieved data show comparable precision with regard to the lab application. This non-invasive and non-contact field application facilitates the first high-precision phenotyping pipeline based on 3D bunch traits in large plant sets.
Development of field navigation system; Field navigation system no kaihatsu
Energy Technology Data Exchange (ETDEWEB)
Ibara, S; Minode, M; Nishioka, K [Daihatsu Motor Co. Ltd., Osaka (Japan)
1995-04-20
This paper describes the following matters on a field navigation system developed for the purpose of covering a field of several kilometer square. This system consists of a center system and a vehicle system, and the center system comprises a map information computer and a communication data controlling computer; since the accuracy for a vehicle position detected by a GPS is not sufficient, an attempt of increasing the accuracy of vehicle position detection is made by means of a hybrid system; the hybrid system uses a satellite navigation method of differential system in which the error components in the GPS are transmitted from the center, and also uses a self-contained navigation method which performs an auxiliary function when the accuracy in the GPS has dropped; corrected GPS values, emergency messages to all of the vehicles and data of each vehicle position are communicated by wireless transmission in two ways between the center and vehicles; and accommodation of the map data adopted a system that can respond quickly to any change in roads and facilities. 3 refs., 13 figs., 1 tab.
BEAMGAA. A chance for high precision analysis of big samples
International Nuclear Information System (INIS)
Goerner, W.; Berger, A.; Haase, O.; Segebade, Chr.; Alber, D.; Monse, G.
2005-01-01
In activation analysis of traces in small samples, the non-equivalence of the activating radiation doses of sample and calibration material gives rise to sometimes tolerable systematic errors. Conversely, analysis of major components usually demands high trueness and precision. To meet this, beam geometry activation analysis (BEAMGAA) procedures have been developed for instrumental photon (IPAA) and neutron activation analysis (INAA) in which the activating neutron/photon beam exhibits broad, flat-topped characteristics. This results in a very low lateral activating flux gradient compared to known radiation facilities, however, at significantly lower flux density. The axial flux gradient can be accounted for by a monitor-sample-monitor assembly. As a first approach, major components were determined in high purity substances as well as selenium in a cattle fodder additive. (author)
Learning for Autonomous Navigation
Angelova, Anelia; Howard, Andrew; Matthies, Larry; Tang, Benyang; Turmon, Michael; Mjolsness, Eric
2005-01-01
Robotic ground vehicles for outdoor applications have achieved some remarkable successes, notably in autonomous highway following (Dickmanns, 1987), planetary exploration (1), and off-road navigation on Earth (1). Nevertheless, major challenges remain to enable reliable, high-speed, autonomous navigation in a wide variety of complex, off-road terrain. 3-D perception of terrain geometry with imaging range sensors is the mainstay of off-road driving systems. However, the stopping distance at high speed exceeds the effective lookahead distance of existing range sensors. Prospects for extending the range of 3-D sensors is strongly limited by sensor physics, eye safety of lasers, and related issues. Range sensor limitations also allow vehicles to enter large cul-de-sacs even at low speed, leading to long detours. Moreover, sensing only terrain geometry fails to reveal mechanical properties of terrain that are critical to assessing its traversability, such as potential for slippage, sinkage, and the degree of compliance of potential obstacles. Rovers in the Mars Exploration Rover (MER) mission have got stuck in sand dunes and experienced significant downhill slippage in the vicinity of large rock hazards. Earth-based off-road robots today have very limited ability to discriminate traversable vegetation from non-traversable vegetation or rough ground. It is impossible today to preprogram a system with knowledge of these properties for all types of terrain and weather conditions that might be encountered.
An Indoor Navigation System for the Visually Impaired
Directory of Open Access Journals (Sweden)
Luis A. Guerrero
2012-06-01
Full Text Available Navigation in indoor environments is highly challenging for the severely visually impaired, particularly in spaces visited for the first time. Several solutions have been proposed to deal with this challenge. Although some of them have shown to be useful in real scenarios, they involve an important deployment effort or use artifacts that are not natural for blind users. This paper presents an indoor navigation system that was designed taking into consideration usability as the quality requirement to be maximized. This solution enables one to identify the position of a person and calculates the velocity and direction of his movements. Using this information, the system determines the user’s trajectory, locates possible obstacles in that route, and offers navigation information to the user. The solution has been evaluated using two experimental scenarios. Although the results are still not enough to provide strong conclusions, they indicate that the system is suitable to guide visually impaired people through an unknown built environment.
An indoor navigation system for the visually impaired.
Guerrero, Luis A; Vasquez, Francisco; Ochoa, Sergio F
2012-01-01
Navigation in indoor environments is highly challenging for the severely visually impaired, particularly in spaces visited for the first time. Several solutions have been proposed to deal with this challenge. Although some of them have shown to be useful in real scenarios, they involve an important deployment effort or use artifacts that are not natural for blind users. This paper presents an indoor navigation system that was designed taking into consideration usability as the quality requirement to be maximized. This solution enables one to identify the position of a person and calculates the velocity and direction of his movements. Using this information, the system determines the user's trajectory, locates possible obstacles in that route, and offers navigation information to the user. The solution has been evaluated using two experimental scenarios. Although the results are still not enough to provide strong conclusions, they indicate that the system is suitable to guide visually impaired people through an unknown built environment.
Damiano, Edward R; McKeon, Katherine; El-Khatib, Firas H; Zheng, Hui; Nathan, David M; Russell, Steven J
2014-07-01
The effectiveness and safety of continuous glucose monitors (CGMs) is dependent on their accuracy and reliability. The objective of this study was to compare 3 CGMs in adult and pediatric subjects with type 1 diabetes under closed-loop blood-glucose (BG) control. Twenty-four subjects (12 adults) with type 1 diabetes each participated in one 48-hour closed-loop BG control experiment. Venous plasma glucose (PG) measurements obtained every 15 minutes (4657 values) were paired in time with corresponding CGM glucose (CGMG) measurements obtained from 3 CGMs (FreeStyle Navigator, Abbott Diabetes Care; G4 Platinum, Dexcom; Enlite, Medtronic) worn simultaneously by each subject. The Navigator and G4 Platinum (G4) had the best overall accuracy, with an aggregate mean absolute relative difference (MARD) of all paired points of 12.3 ± 12.1% and 10.8 ± 9.9%, respectively. Both had lower MARDs of all paired points than Enlite (17.9 ± 15.8%, P 50%) were less common with the G4 (0.5%) than with the Enlite (4.3%, P = .0001) while the number of very large errors with the Navigator (1.4%) was intermediate between the G4 and Enlite (P = .1 and P = .06, respectively). The average MARD for experiments in adolescent subjects were lower than in adult subjects for the Navigator and G4, while there was no difference for Enlite. All 3 devices had similar reliability. A comprehensive head-to-head-to-head comparison of 3 CGMs revealed marked differences in both accuracy and precision. The Navigator and G4 were found to outperform the Enlite in these areas. © 2014 Diabetes Technology Society.
Designing compensator of dual servo system for high precision positioning
International Nuclear Information System (INIS)
Choi, Hyeun Seok; Song, Chi Woo; Han, Chang Soo; Choi, Tae Hoon; Lee, Nak Kyu; Na, Kyung Hwan
2003-01-01
The high precision positioning mechanism is used in various industrial fields. It is used in semiconductor manufacturing line, test instrument, bioengineering, and MEMS and so on. This paper presents a positioning mechanism with dual servo system. Dual servo system consists of a coarse stage and a fine motion stage. The course stage is driven by VCM and the actuator of fine stage is the PZT. The purposes of dual servo system are stability, higher bandwidth, and robustness. Lead compensator is applied to this control system, and is designed by PQ method. Designed compensator can improve property of positioning mechanism
Effects of Navigated Repetitive Transcranial Magnetic Stimulation After Stroke.
Chervyakov, Alexander V; Poydasheva, Alexandra G; Lyukmanov, Roman H; Suponeva, Natalia A; Chernikova, Ludmila A; Piradov, Michael A; Ustinova, Ksenia I
2018-03-01
The purpose of this study was to test the effects of navigated repetitive transcranial magnetic stimulation, delivered in different modes, on motor impairments and functional limitations after stroke. The study sample included 42 patients (58.5 ± 10.7 years; 26 males) who experienced a single unilateral stroke (1-12 months previously) in the area of the middle cerebral artery. Patients completed a course of conventional rehabilitation, together with 10 sessions of navigated repetitive transcranial magnetic stimulation or sham stimulation. Stimulation was scheduled five times a week over two consecutive weeks in an inpatient clinical setting. Patients were randomly assigned to one of four groups and received sham stimulation (n = 10), low-frequency (1-Hz) stimulation of the nonaffected hemisphere (n = 11), high-frequency (10-Hz) stimulation of the affected hemisphere (n = 13), or sequential combination of low- and high-frequency stimulations (n = 8). Participants were evaluated before and after stimulation with clinical tests, including the arm and hand section of the Fugl-Meyer Assessment Scale, modified Ashworth Scale of Muscle Spasticity, and Barthel Index of Activities of Daily Living. Participants in the three groups receiving navigated repetitive transcranial magnetic stimulation showed improvements in arm and hand functions on the Fugl-Meyer Stroke Assessment Scale. Ashworth Scale of Muscle Spasticity and Barthel Index scores were significantly reduced in groups receiving low- or high-frequency stimulation alone. Including navigated repetitive transcranial magnetic stimulation in a conventional rehabilitation program positively influenced motor and functional recovery in study participants, demonstrating the clinical potential of the method. The results of this study will be used for designing a large-scale clinical trial.
Parsimonious Ways to Use Vision for Navigation
Directory of Open Access Journals (Sweden)
Paul Graham
2012-05-01
Full Text Available The use of visual information for navigation appears to be a universal strategy for sighted animals, amongst which, one particular group of expert navigators are the ants. The broad interest in studies of ant navigation is in part due to their small brains, thus biomimetic engineers expect to be impressed by elegant control solutions, and psychologists might hope for a description of the minimal cognitive requirements for complex spatial behaviours. In this spirit, we have been taking an interdisciplinary approach to the visual guided navigation of ants in their natural habitat. Behavioural experiments and natural image statistics show that visual navigation need not depend on the remembering or recognition of objects. Further modelling work suggests how simple behavioural routines might enable navigation using familiarity detection rather than explicit recall, and we present a proof of concept that visual navigation using familiarity can be achieved without specifying when or what to learn, nor separating routes into sequences of waypoints. We suggest that our current model represents the only detailed and complete model of insect route guidance to date. What's more, we believe the suggested mechanisms represent useful parsimonious hypotheses for the visually guided navigation in larger-brain animals.
Risk management model of winter navigation operations
International Nuclear Information System (INIS)
Valdez Banda, Osiris A.; Goerlandt, Floris; Kuzmin, Vladimir; Kujala, Pentti; Montewka, Jakub
2016-01-01
The wintertime maritime traffic operations in the Gulf of Finland are managed through the Finnish–Swedish Winter Navigation System. This establishes the requirements and limitations for the vessels navigating when ice covers this area. During winter navigation in the Gulf of Finland, the largest risk stems from accidental ship collisions which may also trigger oil spills. In this article, a model for managing the risk of winter navigation operations is presented. The model analyses the probability of oil spills derived from collisions involving oil tanker vessels and other vessel types. The model structure is based on the steps provided in the Formal Safety Assessment (FSA) by the International Maritime Organization (IMO) and adapted into a Bayesian Network model. The results indicate that ship independent navigation and convoys are the operations with higher probability of oil spills. Minor spills are most probable, while major oil spills found very unlikely but possible. - Highlights: •A model to assess and manage the risk of winter navigation operations is proposed. •The risks of oil spills in winter navigation in the Gulf of Finland are analysed. •The model assesses and prioritizes actions to control the risk of the operations. •The model suggests navigational training as the most efficient risk control option.
High Precision Current Control for the LHC Main Power Converters
Thiesen, H; Hudson, G; King, Q; Montabonnet, V; Nisbet, D; Page, S
2010-01-01
Since restarting at the end of 2009, the LHC has reached a new energy record in March 2010 with the two 3.5 TeV beams. To achieve the performance required for the good functioning of the accelerator, the currents in the main circuits (Main Bends and Main Quadrupoles) must be controlled with a higher precision than ever previously requested for a particle accelerator at CERN: a few parts per million (ppm) of nominal current. This paper describes the different challenges that were overcome to achieve the required precision for the current control of the main circuits. Precision tests performed during the hardware commissioning of the LHC illustrate this paper.
Adaptive Landmark-Based Navigation System Using Learning Techniques
DEFF Research Database (Denmark)
Zeidan, Bassel; Dasgupta, Sakyasingha; Wörgötter, Florentin
2014-01-01
The goal-directed navigational ability of animals is an essential prerequisite for them to survive. They can learn to navigate to a distal goal in a complex environment. During this long-distance navigation, they exploit environmental features, like landmarks, to guide them towards their goal. In...... hexapod robots. As a result, it allows the robots to successfully learn to navigate to distal goals in complex environments.......The goal-directed navigational ability of animals is an essential prerequisite for them to survive. They can learn to navigate to a distal goal in a complex environment. During this long-distance navigation, they exploit environmental features, like landmarks, to guide them towards their goal....... Inspired by this, we develop an adaptive landmark-based navigation system based on sequential reinforcement learning. In addition, correlation-based learning is also integrated into the system to improve learning performance. The proposed system has been applied to simulated simple wheeled and more complex...
A navigational evaluation model for content management systems
International Nuclear Information System (INIS)
Gilani, S.; Majeed, A.
2016-01-01
Web applications are widely used world-wide, however it is important that the navigation of these websites is effective, to enhance usability. Navigation is not limited to links between pages, it is also how we complete a task. Navigational structure presented as hypertext is one of the most important component of the Web application besides content and presentation. The main objective of this paper is to explore the navigational structure of various open source Content Management Systems from the developer's perspective. For this purpose three CMS are chosen which are WordPress, Joomla, and Drupal. Objective of the research is to identify the important navigational aspects present in these CMSs. Moreover, a comparative study of these CMSs in terms of navigational support is required. For this purpose an industrial survey is conducted based on our proposed navigational evaluation model. The results shows that there exist correlation between the identified factors and these CMSs provide helpful and effective navigational support to their users. (author)
Wallner, Jürgen; Reinbacher, Knut Ernst; Pau, Mauro; Feichtinger, Matthias
2014-01-01
Inferior alveolar nerve block (IANB) anesthesia is a common local anesthetic procedure. Although IANB anesthesia is known for its safety, complications can still occur. Today immediately or delayed occurring disorders following IANB anesthesia and their treatment are well-recognized. We present a case of a patient who developed a symptomatic abscess in the pterygoid region as a result of several inferior alveolar nerve injections. Clinical symptoms included diffuse pain, reduced mouth opening and jaw's hypomobility and were persistent under a first step conservative treatment. Since image-based navigated interventions have gained in importance and are used for various procedures a navigated surgical intervention was initiated as a second step therapy. Thus precise, atraumatic surgical intervention was performed by an optical tracking system in a difficult anatomical region. A symptomatic abscess was treated by a computed tomography-based navigated surgical intervention at our department. Advantages and disadvantages of this treatment strategy are evaluated.
Wallner, Jürgen; Reinbacher, Knut Ernst; Pau, Mauro; Feichtinger, Matthias
2014-01-01
Inferior alveolar nerve block (IANB) anesthesia is a common local anesthetic procedure. Although IANB anesthesia is known for its safety, complications can still occur. Today immediately or delayed occurring disorders following IANB anesthesia and their treatment are well-recognized. We present a case of a patient who developed a symptomatic abscess in the pterygoid region as a result of several inferior alveolar nerve injections. Clinical symptoms included diffuse pain, reduced mouth opening and jaw's hypomobility and were persistent under a first step conservative treatment. Since image-based navigated interventions have gained in importance and are used for various procedures a navigated surgical intervention was initiated as a second step therapy. Thus precise, atraumatic surgical intervention was performed by an optical tracking system in a difficult anatomical region. A symptomatic abscess was treated by a computed tomography-based navigated surgical intervention at our department. Advantages and disadvantages of this treatment strategy are evaluated. PMID:24987612
Fusion of navigational data in River Information Services
Kazimierski, W.
2009-04-01
River Information Services (RIS) is the complex system of solutions and services for inland shipping. It has been the scope of works carried out in most of European countries for last several years. There were also a few major pan-European projects like INDRIS or COMPRIS launched for these purposes. The main idea of RIS is to harmonize the activities of various companies, authorities and other users of inland waterways in Europe. In the last time growing activity in this area in Poland can be also noticed. The leading example can be the works carried out in Chair of Geoinformatics in Maritime University of Szczecin regarding RIS for the needs of Odra River. The Directive 2005/44/EC of European Parliament and Europe Council, followed by European Commission regulations, give precise guidelines on implementing RIS in Europe, stating the services that should be provided. Among them Traffic Information and Traffic Management services can be found. As per guidelines they should be based on tracking and tracing of ships in the inland waters. The results of tracking and tracing are Tactical Traffic Image and Strategic Traffic Image. The guidelines stated that, tracking and tracing system in RIS shall consist of various type sensors. The most important of them is thought to be Automatic Information System (AIS), and particularly its river version - Inland AIS. It is based on determining the position of ships by satellite positioning systems (mainly DGPS) and transmitting it to other users on radio VHF frequences. This guarantees usually high accuracy of data related to movement of ships (assuming proper functioning of system and ship's sensors), and gives the possibility of transmitting additional information about ship, like dimensions, port of destination, cargo, etc. However the other sensors that can be used for tracking shall not be forgotten. The most important of them are radar (traditionally used for tracking purposes in Vessel Traffic Systems) and video camera
Status and outlook of CHIP-TRAP: The Central Michigan University high precision Penning trap
Redshaw, M.; Bryce, R. A.; Hawks, P.; Gamage, N. D.; Hunt, C.; Kandegedara, R. M. E. B.; Ratnayake, I. S.; Sharp, L.
2016-06-01
At Central Michigan University we are developing a high-precision Penning trap mass spectrometer (CHIP-TRAP) that will focus on measurements with long-lived radioactive isotopes. CHIP-TRAP will consist of a pair of hyperbolic precision-measurement Penning traps, and a cylindrical capture/filter trap in a 12 T magnetic field. Ions will be produced by external ion sources, including a laser ablation source, and transported to the capture trap at low energies enabling ions of a given m / q ratio to be selected via their time-of-flight. In the capture trap, contaminant ions will be removed with a mass-selective rf dipole excitation and the ion of interest will be transported to the measurement traps. A phase-sensitive image charge detection technique will be used for simultaneous cyclotron frequency measurements on single ions in the two precision traps, resulting in a reduction in statistical uncertainty due to magnetic field fluctuations.
Energy Technology Data Exchange (ETDEWEB)
Halverson, Samuel; Roy, Arpita; Mahadevan, Suvrath [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Schwab, Christian, E-mail: shalverson@psu.edu [Macquarie University, Sydney, NSW 2109 (Australia)
2015-12-01
Exploring the use of single-mode fibers (SMFs) in high precision Doppler spectrometers has become increasingly attractive since the advent of diffraction-limited adaptive optics systems on large-aperture telescopes. Spectrometers fed with these fibers can be made significantly smaller than typical “seeing-limited” instruments, greatly reducing cost and overall complexity. Importantly, classical mode interference and speckle issues associated with multi-mode fibers, also known as “modal noise,” are mitigated when using SMFs, which also provide perfect radial and azimuthal image scrambling. However, SMFs do support multiple polarization modes, an issue that is generally ignored for larger-core fibers given the large number of propagation modes. Since diffraction gratings used in most high resolution astronomical instruments have dispersive properties that are sensitive to incident polarization changes, any birefringence variations in the fiber can cause variations in the efficiency profile, degrading illumination stability. Here we present a cautionary note outlining how the polarization properties of SMFs can affect the radial velocity (RV) measurement precision of high resolution spectrographs. This work is immediately relevant to the rapidly expanding field of diffraction-limited, extreme precision RV spectrographs that are currently being designed and built by a number of groups.
Space Launch Systems Block 1B Preliminary Navigation System Design
Oliver, T. Emerson; Park, Thomas; Anzalone, Evan; Smith, Austin; Strickland, Dennis; Patrick, Sean
2018-01-01
NASA is currently building the Space Launch Systems (SLS) Block 1 launch vehicle for the Exploration Mission 1 (EM-1) test flight. In parallel, NASA is also designing the Block 1B launch vehicle. The Block 1B vehicle is an evolution of the Block 1 vehicle and extends the capability of the NASA launch vehicle. This evolution replaces the Interim Cryogenic Propulsive Stage (ICPS) with the Exploration Upper Stage (EUS). As the vehicle evolves to provide greater lift capability, increased robustness for manned missions, and the capability to execute more demanding missions so must the SLS Integrated Navigation System evolved to support those missions. This paper describes the preliminary navigation systems design for the SLS Block 1B vehicle. The evolution of the navigation hard-ware and algorithms from an inertial-only navigation system for Block 1 ascent flight to a tightly coupled GPS-aided inertial navigation system for Block 1B is described. The Block 1 GN&C system has been designed to meet a LEO insertion target with a specified accuracy. The Block 1B vehicle navigation system is de-signed to support the Block 1 LEO target accuracy as well as trans-lunar or trans-planetary injection accuracy. Additionally, the Block 1B vehicle is designed to support human exploration and thus is designed to minimize the probability of Loss of Crew (LOC) through high-quality inertial instruments and robust algorithm design, including Fault Detection, Isolation, and Recovery (FDIR) logic.