Abstract: Techniques are provided for Enhanced Message-to-Code Data Tie (EMCDT) for electronic message authentication. A processor may receive a navigation message with navigation data that requires authentication and adheres to a delayed key disclosure protocol. There may be a service interruption to the authentication service. The processor can still authenticate the navigation data based on performance of an EMCDT algorithm that uses a Message Authentication Code and Key (MACK) MACK that corresponds to previously authenticated navigation message. Specifically, the MACK for the previously authenticated message can be used when the transmitter identifier of the navigation data to be authenticated matches a PRND value associated with the previously authenticated message and when a version identifier of the navigation data to be authenticated matches the version identifier of the previously authenticated message.

Abstract: A system and method for a navigation system (NS) including global navigation satellite system (GNSS) spoofing detection using deep learning, such as a neural network, is provided. A GNSS signal is received by a receiver and one or more metrics are obtained from the received signal. Optionally, one or more non-GNSS signal metrics may also be obtained, e.g., information from an inertial measurement unit, vision system, independent time source, etc. The various metrics are fed into a trained neural network that decides as to whether spoofing is present and, if so, what is the type of spoofing that is occurring.

Abstract: Techniques are provided for estimating a line bias of a multi-antenna array. Diff-carrier phase (CP) values may be calculated based on navigation signals received at two antennas of the multi-antenna array. An integer portion may be removed from each diff-CP value. A baseline vector and a fine line bias estimate may be calculated for each of the plurality of candidate line bias value by executing an algorithm that uses each candidate with fractional diff-CP measurements that are corrected for the candidate that is being tested. Output of a test statistic method (e.g., sum of residual squares) and the smallest fine line bias estimate may be used to identify a particular candidate line bias value. The smallest fine line bias estimate may be added to the chosen candidate to calculate the line bias between the two antennas. Calibration of the multi-antenna array and attitude determination can be jointly performed.

Abstract: A system and method for detecting spoofing of a Global Navigation Satellite System (GNSS) system using a plurality of antennas. Signals received by at least two of the plurality of antennas are authentication by use of one or more of a carrier phase authentication procedure, a signal power authentication procedure, and/or a channel distortion authentication procedure.

Abstract: A system and method for detecting spoofing of a navigation system (NS) using a plurality of antennas. Carrier phase and CN0 measurements are obtains of a plurality of signals. The measurements are then double differenced and compared to predefined thresholds to determine whether a signal is authentic or not. Once sufficient authentic signals are identified, position and time is determined using the authenticated signals. Residuals are estimated for all signals. An average value of the residuals or the authenticated signals is calculated and is then removed from the residuals of the unauthenticated signals. Should the remainder exceed a predefined threshold, the signal is deemed to be spoofed. Otherwise, the signal is deemed to be authentic.

Abstract: A system and method for detecting spoofing of a Global Navigation Satellite System (GNSS) system using a plurality of antennas. Signals received by at least two of the plurality of antennas are authentication by use of one or more of a carrier phase authentication procedure, a signal power authentication procedure, and/or a channel distortion authentication procedure.

Abstract: A system and method for detecting spoofing of a navigation system (NS) using a plurality of antennas. Carrier phase and CN0 measurements are obtains of a plurality of signals. The measurements are then double differenced and compared to predefined thresholds to determine whether a signal is authentic or not. Once sufficient authentic signals are identified, position and time is determined using the authenticated signals. Residuals are estimated for all signals. An average value of the residuals or the authenticated signals is calculated and is then removed from the residuals of the unauthenticated signals. Should the remainder exceed a predefined threshold, the signal is deemed to be spoofed. Otherwise, the signal is deemed to be authentic.

Abstract: A system and method for detecting spoofing of global navigation satellite system (GNSS) signals using a single antenna is provided.

Abstract: A system and method for detecting spoofing of a Global Navigation Satellite System (GNSS) system using a plurality of antennas. Signals received by at least two of the plurality of antennas are authentication by use of one or more of a carrier phase authentication procedure, a signal power authentication procedure, and/or a channel distortion authentication procedure.

Abstract: A system and method for detecting spoofing of a Global Navigation Satellite System (GNSS) system using a plurality of antennas. Signals received by at least two of the plurality of antennas are authentication by use of one or more of a carrier phase authentication procedure, a signal power authentication procedure, and/or a channel distortion authentication procedure.

Abstract: A system and method for detecting spoofing of a Global Navigation Satellite System (GNSS) system using a plurality of antennas. Signals received by at least two of the plurality of antennas are authentication by use of one or more of a carrier phase authentication procedure, a signal power authentication procedure, and/or a channel distortion authentication procedure.

Abstract: Techniques are provided for GNSS carrier phase multipath mitigation using a blanked correlator in conjunction with a full correlator. A tracking loop may track a carrier of the GNSS signal utilizing the full correlator. A chip-edge accumulation (CEA) unit of the tracking loop may accumulate chip edges of a ranging code to generate CEA output. A blanked correlator may receive the CEA output to generate blanked correlator values. A running-sum filter may utilize the blanked correlator values to generate a running-sum value. A phase estimate may utilize the running-sum value to generate phase estimator output. In an exemplary embodiment, the blanked correlator operates as a monitoring correlator and the phases estimator output is the estimated carrier phase multipath error. In an exemplary embodiment, the blanked correlator provides input to the tracking loop and discriminator output is subtracted from the phase estimator output to generate the estimated carrier phase multipath error.

Abstract: Structures and techniques are disclosed that can be used to reduce or remove code multipath error in GNSS receivers by implementing one or more monitoring correlators in a multipath-error estimation and correction (MEC) module. The MEC module detects and provides for correction of correlation peak distortion. In exemplary embodiments, a code tracking loop integrates all-chip-edges of a PRN, and a narrow-correlator is used to update the tracking loop rate while a multipath estimation module implements a blanked correlator to estimate and remove the multipath bias from the code tracking loop measurements.

Abstract: A system and method for detecting spoofing of a Global Navigation Satellite System (GNSS) system using a plurality of antennas. Signals received by at least two of the plurality of antennas are authentication by use of one or more of a carrier phase authentication procedure, a signal power authentication procedure, and/or a channel distortion authentication procedure.

Abstract: Techniques are provided for GNSS carrier phase multipath mitigation using a blanked correlator in conjunction with a full correlator. A tracking loop may track a carrier of the GNSS signal utilizing the full correlator. A chip-edge accumulation (CEA) unit of the tracking loop may accumulate chip edges of a ranging code to generate CEA output. A blanked correlator may receive the CEA output to generate blanked correlator values. A running-sum filter may utilize the blanked correlator values to generate a running-sum value. A phase estimate may utilize the running-sum value to generate phase estimator output. In an exemplary embodiment, the blanked correlator operates as a monitoring correlator and the phases estimator output is the estimated carrier phase multipath error. In an exemplary embodiment, the blanked correlator provides input to the tracking loop and discriminator output is subtracted from the phase estimator output to generate the estimated carrier phase multipath error.

Abstract: Structures and techniques are disclosed that can be used to reduce or remove code multipath error in GNSS receivers by implementing one or more monitoring correlators in a multipath-error estimation and correction (MEC) module. The MEC module detects and provides for correction of correlation peak distortion. In exemplary embodiments, a code tracking loop integrates all-chip-edges of a PRN, and a narrow-correlator is used to update the tracking loop rate while a multipath estimation module implements a blanked correlator to estimate and remove the multipath bias from the code tracking loop measurements.

Abstract: A system and method for detecting spoofing of global navigation satellite system (GNSS) signals using a single antenna is provided.

Abstract: Systems and methods for detecting spoofed or illegitimate GNSS signals. A processor receives GNSS data and processes this data to extract acceleration, angular velocity, and height or altitude variation data. For the same time period, sensor data from IMU (inertial measurement unit) sensors and from a barometer are received by the processor. From the sensor data, the processor extracts similar acceleration, angular velocity, and height variation data. These two sets of data are then correlated and correlation coefficients are calculated. These correlation coefficients are then used to calculate a decision statistic. The decision statistic is compared with a predetermined value and, if the decision statistic is below a predetermined value, then the GNSS data is considered to be illegitimate or spoofed.

Abstract: Systems and methods for detecting spoofed or illegitimate GNSS signals. A processor receives GNSS data and processes this data to extract acceleration, angular velocity, and height or altitude variation data. For the same time period, sensor data from IMU (inertial measurement unit) sensors and from a barometer are received by the processor. From the sensor data, the processor extracts similar acceleration, angular velocity, and height variation data. These two sets of data are then correlated and correlation coefficients are calculated. These correlation coefficients are then used to calculate a decision statistic. The decision statistic is compared with a predetermined value and, if the decision statistic is below a predetermined value, then the GNSS data is considered to be illegitimate or spoofed.

Abstract: Embodiments of the invention are directed to GNSS anti-interference using array processing. In one embodiment, a device may be configured to receive signals GNSS signals. In one embodiment, the signals may include a superposition of GNSS signals from independent transmitter sources and a spoofing signal. The spoofing signal may include several pseudo random noise (PRN) codes originating from a single transmitter source. In a one embodiment, the device may include multiple radio frequency (RF) inputs connected to multiple antennas and may use a combining algorithm to produce a weighted sum of the antenna outputs. The resultant sum may be passed through an output port of the device that is configured to be coupled to an RF input port of a GNSS receiver.