Abstract: A method for the coherent tracking of a time varying signal using evolutionary computing including global and local optimization techniques for the purpose of obtaining better performance under poor signal reception conditions, multipath errors, indoors, and for obtaining more accurate estimates of carrier phase, carrier frequency, and modulation phase at low signal levels without being subject to the traditional phase lock tracking loops (PLL) or delay lock tracking loops (DLL) limitations.

Abstract: A coherent process for the acquiring and tracking of time varying signals includes receiving a time varying signal, sampling the received time varying signal, processing received data samples of the time varying signal using a global optimization method and processing received data samples of the time varying signal using a local optimization method.

Abstract: An improved approach to satellite-based navigation (e.g., GPS) is provided. In one embodiment, a method includes receiving a first set of tracking information. A nominal orbital path for the navigation satellite is determined using the first set of tracking information. Ephemeris data corresponding to the nominal orbital path is computed and uploaded to the navigation satellite. Long-term navigation information corresponding to the nominal orbital path is transmitted to a communication system for broadcast to a plurality of navigation devices. A second set of tracking information is received, an orbital path of the navigation satellite using the second set of tracking information is predicted, and a difference between the predicted orbital path and the nominal orbital path is determined. Commands configured to instruct the navigation satellite to adjust an actual orbital path of the navigation satellite to substantially conform to the nominal orbital path are uploaded to the navigation satellite.

Abstract: A system that provides GPS-based navigation/orbit determination capabilities for high-altitude spacecraft. The system uses an existing spacecraft processor and an easy-to-space-qualify minimum-hardware front end to minimize the need for new space-qualified hardware. The system also uses coherent integration to acquire and track the very weak GPS signals at high altitudes. The system also uses diurnal thermal modeling of a spacecraft clock and precision orbit propagation to enable longer coherent integration, a special Kalman filter to allow weak signal tracking by integrated operation of orbit determination and GPS signal tracking, and a segment-by-segment, post-processing, delayed-time approach to allow a low-speed spacecraft processor to provide the software GPS capability.

Abstract: An improved approach to satellite-based navigation (e.g., GPS) is provided. In one embodiment, a method includes determining a nominal orbital path of a navigation satellite. The method also includes transmitting ephemeris data corresponding to the nominal orbital path from the navigation satellite to a plurality of navigation devices. The method further includes determining an actual orbital path of the navigation satellite locally at the navigation satellite. In addition, the method includes determining a deviation between the actual orbital path and the nominal orbital path locally at the navigation satellite. The method also includes autonomously adjusting the actual orbital path locally at the navigation satellite to reduce the deviation between the actual orbital path and the nominal orbital path.

Abstract: A system that provides GPS-based navigation/orbit determination capabilities for high-altitude spacecraft. The system uses an existing spacecraft processor and an easy-to-space-qualify minimum-hardware front end to minimize the need for new space-qualified hardware. The system also uses coherent integration to acquire and track the very weak GPS signals at high altitudes. The system also uses diurnal thermal modeling of a spacecraft clock and precision orbit propagation to enable longer coherent integration, a special Kalman filter to allow weak signal tracking by integrated operation of orbit determination and GPS signal tracking, and a segment-by-segment, post-processing, delayed-time approach to allow a low-speed spacecraft processor to provide the software GPS capability.

Abstract: A system and method autonomously and precisely track objects moving along a known course. The objects include, for example, racing horses, other racing animals, or racing vehicles. The system and method utilize modern satellite navigation satellite systems, signal processing, radio communications systems and computer processing to acquire and analyze performance data of the moving objects during competitions and during training and practice. The data acquisition is performed continuously at a rate of at least 1 Hz during the competition, training or practice even in the presence of objects which affect the quality of the signals received from the satellite system.

Abstract: User equipment navigation solution with position determination of a navigation signal reflector methods and systems are described. In an embodiment, navigation signals transmitted from global positioning system (GPS) platform(s) can be received at a GPS-enabled receiver as direct navigation signals and reflected navigation signals. The direct navigation signals can then be isolated from the reflected navigation signals. Receiver range measurements can be determined from the direct navigation signals which are received via direct signal paths from the GPS platform(s), and a navigation solution of the GPS-enabled receiver can then be resolved from the receiver range measurements. Similarly, reflector range measurements can be determined from the reflected navigation signals which are received via reflected signal paths from a signal reflector, and a position of the signal reflector can then be resolved from the reflector range measurements at the GPS-enabled receiver.

Abstract: An improved approach to satellite-based navigation (e.g., GPS) is provided. In one embodiment, a method includes determining a nominal orbital path of a navigation satellite. The method also includes transmitting ephemeris data corresponding to the nominal orbital path from the navigation satellite to a plurality of navigation devices. The method further includes determining an actual orbital path of the navigation satellite locally at the navigation satellite. In addition, the method includes determining a deviation between the actual orbital path and the nominal orbital path locally at the navigation satellite. The method also includes autonomously adjusting the actual orbital path locally at the navigation satellite to reduce the deviation between the actual orbital path and the nominal orbital path.

Abstract: An improved approach to satellite-based navigation (e.g., GPS) is provided. In one embodiment, a method includes receiving a first set of tracking information. A nominal orbital path for the navigation satellite is determined using the first set of tracking information. Ephemeris data corresponding to the nominal orbital path is computed and uploaded to the navigation satellite. Long-term navigation information corresponding to the nominal orbital path is transmitted to a communication system for broadcast to a plurality of navigation devices. A second set of tracking information is received, an orbital path of the navigation satellite using the second set of tracking information is predicted, and a difference between the predicted orbital path and the nominal orbital path is determined. Commands configured to instruct the navigation satellite to adjust an actual orbital path of the navigation satellite to substantially conform to the nominal orbital path are uploaded to the navigation satellite.

Abstract: User equipment navigation solution with position determination of a navigation signal reflector methods and systems are described. In an embodiment, navigation signals transmitted from global positioning system (GPS) platform(s) can be received at a GPS-enabled receiver as direct navigation signals and reflected navigation signals. The direct navigation signals can then be isolated from the reflected navigation signals. Receiver range measurements can be determined from the direct navigation signals which are received via direct signal paths from the GPS platform(s), and a navigation solution of the GPS-enabled receiver can then be resolved from the receiver range measurements. Similarly, reflector range measurements can be determined from the reflected navigation signals which are received via reflected signal paths from a signal reflector, and a position of the signal reflector can then be resolved from the reflector range measurements at the GPS-enabled receiver.

Abstract: An IFF device comprises a beam generator for directing an unmodulated beam at a target. The target has a plurality of retro-reflectors mounted on it. These retro-reflectors have internal reflecting surfaces for reflecting the unmodulated beam penetrating the retro-reflector. A device is associated with the internal reflecting surfaces for modulating the beam at a predetermined frequency so that the reflected beam emerging from the retro-reflector is modulated at the same frequency. A tuner is positioned in the path of the reflected modulated beam and tuned to predetermined frequency, so that if the tuner receives a signal, it indicates the target is friendly.

Abstract: A guidance system for of vehicle, such as a model airplane which has directional control devices. A device is mounted on the vehicle or at some remote station to generate a command attitude signal. At least two sensors are mounted on the body of the vehicle and face in opposite directions away from the body of the vehicle. These sensors are connected together in such a way that radiation falling on the sensors causes the sensors to produce a signal such that the signal at the junction between the sensor is functionally related to the orientation of the vehicle. A servo mechanism is mounted on the body of the vehicle and is connected to the directional control devices of the vehicle. An electric circuit is connected between the signal from the sensors and the device that generates a command attitude signal and the servo mechanism.