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: Disclosed is a technique that can provide one or more countermeasures against spoofers. An antenna, movable in space, is used to receive space vehicle (SV) signals that appear to be associated with a plurality of space vehicles of a global navigation satellite system (GNSS). SV signals are identified that have similar signal power and/or phase signatures that respectively appear to be associated with at least a first space vehicle and a second space vehicle of the GNSS. An existence of a spoofer is identified based at least in part on the identification of SV signals that have similar signal power and/or phase signatures that respectively appear to be associated with at least the first space vehicle and the second space vehicle of the GNSS.

Abstract: Disclosed is a technique that can provide one or more countermeasures against spoofers. A beamformer can control an antenna pattern of a CRPA to generate a survey beam. The survey beam is swept across space to determine a characteristic signature based on carrier-to-noise ratios (C/No) for particular space vehicle signals. Matching C/No signatures can be used to identify the existence of spoofers and invoke a countermeasure, such as nulling.

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 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: 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 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: Disclosed is a technique that can provide one or more countermeasures against spoofers. A beamformer can control an antenna pattern of a CRPA to generate a survey beam. The survey beam is swept across space to determine a characteristic signature based on carrier-to-noise ratios (C/No) for particular space vehicle signals. Matching C/No signatures can be used to identify the existence of spoofers and invoke a countermeasure, such as nulling.

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: 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 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: 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: 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: 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 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: Disclosed is a technique that can provide one or more countermeasures against spoofers. A beamformer can control an antenna pattern of a CRPA to generate a survey beam. The survey beam is swept across space to determine a characteristic signature based on carrier-to-noise ratios (C/No) for particular space vehicle signals. Matching C/No signatures can be used to identify the existence of spoofers and invoke a countermeasure, such as nulling.

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.