Measuring human performance with a parameter tracking version of the crossover model
Continuous parameter tracking system for measuring human performance in compensatory control system
HUMAN PERFORMANCE↗
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An interferometer tracking radar system
Fine tuning acquisition and tracking interferometer radar system uses a first antenna array of at least three receiving antennas. Array includes a reference antenna, a coarse tuning antenna, and a fine tuning antenna aligned on a receiving axis. Short range rendezvous system provides increased position accuracy.
Broderick, R. F.↗
Telescope dome control system automatically tracks sun
Automatic control system is designed to rotate a dome so that a telescope, or other instruments, within the dome will continuously view the sun as the earth rotates.
Cashion, K. D.↗
Developing Methods for Exercise System Kinematic Tracking
BACKGROUND How to quantify the load and forces produced by exercise equipment and their Vibration Isolation and Stabilization (VIS) platforms in-flight is an active area of investigation. Kinematic tracking paired with system modeling can provide insights as well as verification and validation of simulations used for system design and development. Traditional motion capture methods can require significant cost in equipment procurement and crew-time, but newer lessons learned can be leveraged [1]. The VIS systems of current and future exercise hardware on the International Space Station (ISS) such as the Cycle Ergometer with Vibration Isolation System (CEVIS) and the European Enhanced Exploration Exercise Device (E4D) are not currently outfitted with IMUs or similar measurement devices. Video-based methods would enable use of multi-purpose, crew-familiar flight equipment. An initial exploration of video-based solutions was performed utilizing 2-camera video from crew cycling on Teal-CEVIS on the ISS. METHODS AND RESULTS Our group has scoped a variety of video-based object tracking methods. To date, we have primarily investigated computer vision toolkits such as open CV. Techniques explored include key-point detection, background subtraction, region-of interest tracking, color-based tracking, tag masking and tracking, and corner detection. Although object-tracking and 6D pose estimation is a rich field, space applications are a unique problem that are challenging for existing software and toolkits. The majority of the existing object-tracking applications involve vehicles/pedestrians and household objects with simple backgrounds. We have identified the following features which pose particular challenges for on-station exercise equipment tracking: 1. Busy and visually cluttered background 2. Low-textured tracking object with relatively small motions 3. Occlusions and motion by human subject and loose, floating objects 4. Limited number of video cameras with no fixed global references 5. Limited ability to add tags, markers, or visual references to the tracking object 6. Lack of training data for Machine Learning (ML) algorithms CONCLUSION We will summarize the efficacy of techniques tested for a ground mock-trial and the on-station exercise trial. It is likely that human-in-loop feedback or a conglomerate of methods is required. ML-based methods, like those implemented for human body tracking [2], may still be a viable option, but more training data and validation is needed.
L Nilsson↗
Developing Methods for Exercise System Kinematics Tracking
BACKGROUND How to quantify the load and forces produced by exercise equipment and their Vibration Isolation and Stabilization (VIS) platforms in-flight is an active area of investigation. Kinematic tracking paired with system modeling can provide insights as well as verification and validation of simulations used for system design and development. Traditional motion capture methods can require significant cost in equipment procurement and crew-time, but newer lessons learned can be leveraged [1]. The VIS systems of current and future exercise hardware on the International Space Station (ISS) such as the Cycle Ergometer with Vibration Isolation System (CEVIS) and the European Enhanced Exploration Exercise Device (E4D) are not currently outfitted with IMUs or similar measurement devices. Video-based methods would enable use of multi-purpose, crew-familiar flight equipment. An initial exploration of video-based solutions was performed utilizing 2-camera video from crew cycling on Teal-CEVIS on the ISS. METHODS AND RESULTS Our group has scoped a variety of video-based object tracking methods. To date, we have primarily investigated computer vision toolkits such as openCV. Techniques explored include key-point detection, background subtraction, region-of interest tracking, color-based tracking, tag masking and tracking, and corner detection. Although object-tracking and 6D pose estimation is a rich field, space applications are a unique problem that are challenging for existing software and toolkits. The majority of the existing object-tracking applications involve vehicles/pedestrians and household objects with simple backgrounds. We have identified the following features which pose particular challenges for on-station exercise equipment tracking: Busy and visually cluttered background Low-textured tracking object with relatively small motions Occlusions and motion by human subject and loose, floating objects Limited number of video cameras with no fixed global references Limited ability to add tags, markers, or visual references to the tracking object Lack of training data for Machine Learning (ML) algorithms CONCLUSION We will summarize the efficacy of techniques tested for a ground mock-trial and the on-station exercise trial. It is likely that human-in-loop feedback or a conglomerate of methods is required. ML-based methods, like those implemented for human body tracking [2], may still be a viable option, but more training data and validation is needed.
L B Nilsson↗
Small perturbation dynamics of the neuromuscular system in tracking tasks
Small perturbation dynamics of neuromuscular system in tracking tasks
Magdaleno, R. P.↗
A feasibility study for measuring stratospheric turbulence using metrac positioning system
The feasibility of obtaining measurements of Lagrangian turbulence at stratospheric altitudes is demonstrated by using the METRAC System to track constant-level balloons. The basis for current estimates of diffusion coefficients are reviewed and it is pointed out that insufficient data is available upon which to base reliable estimates of vertical diffusion coefficients. It is concluded that diffusion coefficients could be directly obtained from Lagrangian turbulence measurements. The METRAC balloon tracking system is shown to possess the necessary precision in order to resolve the response of constant-level balloons to turbulence at stratospheric altitudes. A small sample of data recorded from a tropospheric tetroon flight tracked by the METRAC System is analyzed to obtain estimates of small-scale three-dimensional diffusion coefficients. It is recommended that this technique be employed to establish a climatology of diffusion coefficients and to ascertain the variation of these coefficients with altitude, season, and latitude.
Gage, K. S.↗
Communications and tracking expert systems study
The original objectives of the study consisted of five broad areas of investigation: criteria and issues for explanation of communication and tracking system anomaly detection, isolation, and recovery; data storage simplification issues for fault detection expert systems; data selection procedures for decision tree pruning and optimization to enhance the abstraction of pertinent information for clear explanation; criteria for establishing levels of explanation suited to needs; and analysis of expert system interaction and modularization. Progress was made in all areas, but to a lesser extent in the criteria for establishing levels of explanation suited to needs. Among the types of expert systems studied were those related to anomaly or fault detection, isolation, and recovery.
Leibfried, T. F.↗
Earth/Moon System Star Tracking Sensor for Improved Deep Space Laser Communications
The goal of this research is to improve deep space communication links by exploring a new concept in stellar navigation that uses images of the Earth/Moon system to obtain precise pointing information so that the laser signal from the satellite can be directed at the ground station with unprecedented accuracy. Currently, the concept for satellite pointing relies on a dual axis star tracker that compares images of the celestial sphere to a star catalog to obtain a 3-axis orientation solution. Most star trackers are designed with a wide field of view (required to obtain enough bright starts to achieve a navigational fix) and only provide reliable pitch and yaw estimates thus necessitating the use of a second star tracker looking at an axis perpendicular to the first one to obtain an accurate estimate of the roll of the spacecraft. In the new concept the optical design will be modified to ensure that both the Earth and the Moon will be within a narrow field of view centered on Earth relative to the field of view of most star tracking systems. Because of the proximity of the bodies, it is possible to obtain highly accurate estimates of the pitch, yaw and roll of the spacecraft relative to the Earth/Moon system. The new tracker will allow for accurate 3-axis control of the spacecraft from a single tracker thus allowing the second star tracker, which would normally be pointed in a direction perpendicular to the one pointed at earth, to obtain the spacecraft roll estimate. This wide field star tracker facilitates functions like the initial satellite pointing during the acquisition phase of establishing the laser communication link or solving the lost in space problem should the system need to be reset. This new design will be tested in simulation and compared for 3-axis pointing accuracy against a standard commercial star tracker.
Star tracker↗
Satellite tracking by combined optimal estimation and control techniques.
Combined optimal estimation and control techniques are applied for the first time to satellite tracking systems. Both radio antenna and optical tracking systems of NASA are considered. The optimal estimation is accomplished using an extended Kalman filter resulting in an estimated state of the satellite and of the tracking system. This estimated state constitutes an input to the optimal controller. The optimal controller treats a linearized system with a quadratic performance index. The maximum principle is applied and a steady-state approximation to the resulting Riccati equation is obtained. A computer program, RATS, implementing this algorithm is described. A feasibility study of real-time implementation, tracking simulations, and parameter sensitivity studies are also reported.
Dressler, R. M.↗
Satellite altitude determination uncertainties
Satellite altitude determination uncertainties are discussed from the standpoint of the GEOS-C satellite. GEOS-C will be tracked by a number of the conventional satellite tracking systems, as well as by two advanced systems; a satellite-to-satellite tracking system and lasers capable of decimeter accuracies which are being developed in connection with the Goddard Earth and Ocean Dynamics Applications program. The discussion is organized in terms of a specific type of GEOS-C orbit which would satisfy a number of scientific objectives including the study of the gravitational field by means of both the altimeter and the satellite-to-satellite tracking system, studies of tides, and the Gulf Stream meanders.
Siry, J. W.↗
Portable Catapult Launcher For Small Aircraft
An apparatus for launching an aircraft having a multiplicity of interconnected elongated tracks of rigid material forming a track system and wherein each elongated track has a predetermined elongated track cross-sectional design, a winch system connected to the track system wherein the winch system has a variable mechanical advantage, one or more elongated elastic members wherein one end of each of the one or more elongated elastic members is adjustably connected to the track system, and a carrier slidably mounted to the track system wherein the canier is connected to the winch system and to the other end of each of the one or more elongated elastic members.
Rosenbaum, Bernard J.↗
Portable catapult launcher for small aircraft
An apparatus for launching an aircraft having a multiplicity of interconnected elongated tracks of rigid material forming a track system and wherein each elongated track has a predetermined elongated track cross-sectional design, a winch system connected to the track system wherein the winch system has a variable mechanical advantage, one or more elongated elastic members wherein one end of each of the one or more elongated elastic members is adjustably connected to the track system, and a carrier slidably mounted to the track system wherein the carrier is connected to the winch system and to the other end of each of the one or more elongated elastic members.
Rosenbaum, Bernard J.↗
Parametric analysis of microwave and laser systems for communication and tracking. Volume 2 - System selection
System selection criteria of microwave and laser systems for communication and tracking - Vol. 2
Brinkman, K. L.↗
Performance evaluation of the JPL TOPSAR system: An across-track interferometric SAR system for topographic mapping
An across-track interferometric (XTI) SAR has the capability of determining the three dimensional target location from the recorded radar echos thus providing high spatial resolution both horizontally and vertically. The output of an XTI SAR will typically include both a radar backscatter map and a digital elevation model (DEM). The accuracy of the derived DEM is determined by factors such as data acquisition geometry, signal-to-noise ratio, knowledge of platform position and attitude as well as the accuracy of the processing system. In the summer of 1992 the authors acquired TOPSAR data over the Ft. Irwin area in California, a desert area with significant relief (height standard deviation 150 m). Very accurate DEM's have been derived for this area by the Topographic Engineering Center (TEC) using digital correlation methods on 1:20,000 scale digitized photographs. Corner reflectors were deployed in the area, and their locations were determined to cm accuracies by the Defense Mapping Agency (DMA) using differential GPS techniques. DEM's generated from the acquired radar data have been rotated and translated to overlay the reference DEM's provided by TEC. A detailed description of the errors and their characteristics will be given. The standard deviations of the radar data sets we acquired measured over a 5.6 by 7 km area were 1.9 and 2.3 m. The corresponding numbers for flat areas were 1.1 and 2.0 m and for mountain areas 3.3 and 2.2 m.
Madsen, Soren N.↗
Laser Tracking and Ranging System
The Laser Tracking and Ranging System (LTRS) is an optical tracking radar that uses a gallium-arsenide injection laser as the transmitting source. The system is designed to track a small retrodirective corner-reflector array and to provide continuously the range, azimuth, and elevation of the array's position relative to the tracking unit. The development effort was directed toward providing a small, compact and relatively lightweight instrument mainly as a part of the Lunar Surveying System for tracking an astronaut's staff. A number of other applications considered include the LTRS as a navigation instrument for a Lunar Flying Vehicle and as a crew safety device for monitoring an astronaut's situation during any EVA operations.
Source record↗
Theory and design of coherent digital systems which track Doppler frequency
Coherent digital communication systems optimal design based on unified theory, discussing tradeoffs between error rates, Doppler tracking capability and time and frequency division multiplexing
Weber, C. L.↗
A precision transportable tracking telemetry system
New mission requirements and the main fetures of a new generation of tracking telemetry system designed to meet these requriements are discussed. The missions include launch vehicle support, sounding rocket mission support, and LEO satellite support, which often require support from remote sites with no existing tracking resources. To meet these requirements, the new system improves on the existing capabilities in three areas: improved RF performance, automation, and target positional accuracy. Initial results of system testing are presented. Without additional adjustment, the new system routinely falls within an absolute accuracy of +/-0.075 degrees, 3 sigma, and on most passes achieves +/-0.05 degrees, 3 sigma.
Morris, R. A.↗