Abstract: Apparatus and methods provide anti-spoofing capability from a first global navigation satellite system (GNSS) receiver to a second GNSS receiver. These GNSS receivers can be, for example, global positioning satellite (GPS) receivers. Via an authentication technique, signals from authentic GNSS sources are distinguished from signals from spoofers. Timing information, such as numerically-controlled oscillator (NCO) settings, used for tracking authenticated signals are then used to generate replica GNSS signals, which are then provided to the second GNSS receiver. As a result, the second GNSS receiver can provide accurate positioning system information in the presence of GNSS spoofers.

Abstract: Apparatus and methods permit the use of a microelectromechanical systems (MEMS) oscillator in a satellite positioning system receiver, such as a Global Positioning System (GPS) receiver. Techniques to ameliorate jitter or phase noise disadvantages associated with MEMS oscillators are disclosed. For example, a receiver can use one or more of the following techniques: (a) use another source of information to retrieve ephemeris information, (2) perform advanced tight coupling, and/or (3) use a phase-locked loop to clean up the jitter or phase noise of the MEMS oscillator. With respect to advanced tight coupling, an advanced tight coupling processor can include nonlinear discriminators which transform I and Q data into linear residual measurements corrupted by unbiased, additive, and white noise. It also includes an amplitude estimator configured to operate in rapidly changing, high power noise; a measurement noise variance estimator; and a linear residual smoothing filter for input to the navigation filter.

Abstract: Disclosed is a technique to estimate at least a portion of an attitude, such as an azimuth angle from true North, based on beam angles from a controlled reception pattern antenna (CRPA) to space vehicle locations. Other attitude information such as roll and/or pitch can also be estimated. The at least portion of the attitude can be provided with or without an additional sensor, such as a compass or magnetometer, an inertial measurement unit (IMU), or the like. An attitude estimate can be useful because oftentimes the attitude of an object can vary from its track or velocity direction.

Abstract: Disclosed is a technique that can provide one or more countermeasures against spoofers. A direction from which a spoofing attack occurs is identified. A beamformer can control an antenna pattern of a CRPA to null out signals from that direction, which can assist a GNSS receiver to avoid error induced by the spoofing attack. Further, after two or more observations, the location of the spoofer can be identified.

Abstract: Apparatus and methods determine the rotational position of a spinning object. A satellite positioning system can be used to determine the spatial position of an object, which in turn can be used to guide the object. An adaptive sideband filter is used to provide increased robustness against interference. However, when the object is spinning, such as an artillery shell, then the rotational orientation should be known in order to properly actuate the control surfaces, such as fins, which will also be spinning.

Abstract: Apparatus and methods determine the rotational position of a spinning object. A satellite positioning system can be used to determine the spatial position of an object, which in turn can be used to guide the object. However, when the object is spinning, such as an artillery shell, then the rotational orientation should be known in order to properly actuate the control surfaces, such as fins, which will also be spinning.

Abstract: Apparatus and methods determine the rotational position of a spinning object. A satellite positioning system can be used to determine the spatial position of an object, which in turn can be used to guide the object. However, when the object is spinning, such as an artillery shell, then the rotational orientation should be known in order to properly actuate the control surfaces, such as fins, which will also be spinning.

Abstract: Apparatus and methods provide a guidance kit that can be attached to a projectile, such as screwed into a fuze well of an artillery round or a mortar round. A portion of the guidance kit is configured to spin constantly during flight. In the context of an artillery round that is shot from a rifled barrel, the direction of the spin torque is counter to the direction of the spin induced by the rifled barrel. Control surfaces are present in the portion of the guidance kit that spins constantly during flight. While the portion spins, the control surfaces are actuated to steer the projectile towards an intended target via, for example, GPS.

Abstract: Apparatus and methods provide a kit for converting a conventional mortar round into a glide bomb. Mortar rounds are readily available to combat personnel and are small and light enough to be carried by relatively small unmanned aerial vehicles (UAVs) such as the RQ-7 Shadow. Advantageously, the kit provides both guidance and relatively good standoff range for the UAV such that the kit-equipped mortar round can be dropped a safe distance away from the intended target so that the UAV is not easily observed near the intended target.

Abstract: Apparatus and methods determine the rotational position of a spinning object. A satellite positioning system can be used to determine the spatial position of an object, which in turn can be used to guide the object. However, when the object is spinning, such as an artillery shell, then the rotational orientation should be known in order to properly actuate the control surfaces, such as fins, which will also be spinning.

Abstract: Apparatus and methods determine the rotational position of a spinning object. A satellite positioning system can be used to determine the spatial position of an object, which in turn can be used to guide the object. However, when the object is spinning, such as an artillery shell, then the rotational orientation should be known in order to properly actuate the control surfaces, such as fins, which will also be spinning.

Abstract: A system and method for generating a navigation solution in high interference and dynamic environments using Global Positioning System (GPS) and navigation such as dead reckoning is described. The system configuration is a multi-satellite tracking loop structure obtained by closing each satellite's tracking loop through a multi-state navigation filter. This generates a robust navigation solution that can track GPS signals in a lower signal to noise ratio than can the standard GPS tightly coupled tracking loops. The system contains an Advanced Tightly Coupled (ATC) tracking processor which accepts early, late, and on-time I and Q data from the GPS signal tracker and outputs vehicle to satellite range, range rate and range acceleration residual measurements to a navigation Kalman filter. The ATC includes nonlinear discriminators which transform I and Q data into residual measurements corrupted by unbiased, additive, and white noise.

Abstract: A system and method for GPS acquisition in relatively high interference is described. Acquisition is aided by an Advanced Tightly Coupled (ATC) tracking filters that compute a satellite range residuals and range rate residuals for satellites being acquired. Multiple channels are used in parallel to search for the desired satellites. Range residuals from the ATC filters are used to correct the computed receiver offset and thus allow acquisition in the presence of relatively high interference.

Abstract: Apparatus and methods determine the rotational position of a spinning object. A satellite positioning system can be used to determine the spatial position of an object, which in turn can be used to guide the object. However, when the object is spinning, such as an artillery shell, then the rotational orientation should be known in order to properly actuate the control surfaces, such as fins, which will also be spinning.

Abstract: A system and method for GPS acquisition in relatively high interference is described. Acquisition is aided by an Advanced Tightly Coupled (ATC) tracking filters that compute a satellite range residuals and range rate residuals for satellites being acquired. Multiple channels are used in parallel to search for the desired satellites. Range residuals from the ATC filters are used to correct the computed receiver offset and thus allow acquisition in the presence of relatively high interference.

Abstract: A system and method for GPS acquisition in relatively high interference is described. Acquisition is aided by an Advanced Tightly Coupled (ATC) tracking filters that compute a satellite range residuals and range rate residuals for satellites being acquired. Multiple channels are used in parallel to search for the desired satellites. Range residuals from the ATC filters are used to correct the computed receiver offset and thus allow acquisition in the presence of relatively high interference.