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: A method and a system for reducing time to first fix (TTFF) in a satellite navigation receiver generate a navigation data structure including three sub-frames. A first sub-frame and a second sub-frame accommodate selective ephemeris data. The third sub-frame accommodates a text message including almanac data optionally, ionospheric data, coordinated universal time (UTC) data, textual data optionally, and any combination thereof. A signal generation system (SGS) in the system selectively groups the almanac data, the ionospheric data, and the UTC data, and selectively transmits the navigation data with the almanac data or free of the almanac data in the navigation data structure to the satellite navigation receiver. The signal generation system also staggers the navigation data in each sub-frame into a first portion and a second portion for parallelly transmitting the navigation data over a first carrier frequency and a second carrier frequency in reduced time.

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: A method and a system for reducing time to first fix (TTFF) in a satellite navigation receiver generate a navigation data structure including three sub-frames. A first sub-frame and a second sub-frame accommodate selective ephemeris data. The third sub-frame accommodates a text message including almanac data optionally, ionospheric data, coordinated universal time (UTC) data, textual data optionally, and any combination thereof. A signal generation system (SGS) in the system selectively groups the almanac data, the ionospheric data, and the UTC data, and selectively transmits the navigation data with the almanac data or free of the almanac data in the navigation data structure to the satellite navigation receiver. The signal generation system also staggers the navigation data in each sub-frame into a first portion and a second portion for parallelly transmitting the navigation data over a first carrier frequency and a second carrier frequency in reduced time.

Abstract: A method and a system for reducing time to first fix (TTFF) in a satellite navigation receiver generate a navigation data structure including three sub-frames. A first sub-frame and a second sub-frame accommodate selective ephemeris data. The third sub-frame accommodates a text message including almanac data optionally, ionospheric data, coordinated universal time (UTC) data, textual data optionally, and any combination thereof. A signal generation system (SGS) in the system selectively groups the almanac data, the ionospheric data, and the UTC data, and selectively transmits the navigation data with the almanac data or free of the almanac data in the navigation data structure to the satellite navigation receiver. The signal generation system also staggers the navigation data in each sub-frame into a first portion and a second portion for parallelly transmitting the navigation data over a first carrier frequency and a second carrier frequency in reduced time.

Abstract: A method and a system for reducing time to first fix (TTFF) in a satellite navigation receiver generate a navigation data structure including three sub-frames. A first sub-frame and a second sub-frame accommodate selective ephemeris data. The third sub-frame accommodates a text message including almanac data optionally, ionospheric data, coordinated universal time (UTC) data, textual data optionally, and any combination thereof. A signal generation system (SGS) in the system selectively groups the almanac data, the ionospheric data, and the UTC data, and selectively transmits the navigation data with the almanac data or free of the almanac data in the navigation data structure to the satellite navigation receiver. The signal generation system also staggers the navigation data in each sub-frame into a first portion and a second portion for parallelly transmitting the navigation data over a first carrier frequency and a second carrier frequency in reduced time.

Abstract: Methods and systems for compensating for gyroscopic errors. A system uses magnetometers to detect and measure a magnetic field local to a personal navigation device. When the local magnetic field is quasi-static, the rate of change of the magnetic field is combined with the rotational rate of change of the device. This generates an estimated gyroscope error. The error can then be used to correct for time-varying inherent gyroscope errors.

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.

Abstract: Systems and methods related to the detection of incoming wireless signals. An antenna array is synthesized by having a single antenna, coupled to a receiver, spatially translated along an arbitrary trajectory. As the antenna is being spatially translated, a data processing means samples the incoming signal based on a clock signal provided by a system clock. By sampling the incoming signal at different times at different spatial locations on the arbitrary trajectory, the system acts as a synthetic antenna array. The different samplings of the incoming signal at different times and positions provide signal diversity gain as well as different readings which can be used to detect an incoming signal. The invention is applicable to detecting a wireless communications signal or a GNSS signal under various conditions. The system may include at least one sensor which can provide data for use in calculating data related to the arbitrary trajectory.

Abstract: A system for estimating parameters of an incoming signal is provided. At least one antenna is coupled to at least one suitable receiver. The antenna(s) are spatially translated in an arbitrary trajectory. As the antenna(s) is being spatially translated, a data processing means samples the incoming signal at set intervals based on a clock signal provided by a system clock. By sampling the incoming signal at different times at different spatial locations on the arbitrary trajectory, the system acts as a synthetic antenna array. The different samplings of the incoming signal at different times and positions provide signal diversity gain as well as different readings which can be used to estimate and/or calculate various parameters of the incoming signal. The different samplings can be used to detect the incoming signal, estimate its angle of arrival, estimate its time of arrival, as well as other parameters.

Abstract: Methods and systems for compensating for gyroscopic errors. A system uses magnetometers to detect and measure a magnetic field local to a personal navigation device. When the local magnetic field is quasi-static, the rate of change of the magnetic field is combined with the rotational rate of change of the device. This generates an estimated gyroscope error. The error can then be used to correct for time-varying inherent gyroscope errors.

Abstract: Methods and systems for detecting GNSS signals originating from an inauthentic source. A synthetic array using a receiver antenna which is randomly spatially translated may be used to gather alleged GNSS signals. The signals are then processed to determine the spatial correlation between them. A high spatial correlation between the signals indicates a probable inauthentic source for the GNSS signals.

Abstract: A method and apparatus for acquiring and tracking a BOC signal in a satellite navigation receiver includes a synthesized acquisition test function or a discriminator for code delay provided by combining a BOC autocorrelation function and a BOC/PRN cross-correlation function.

Abstract: Systems and methods related to the detection of incoming wireless signals. An antenna array is synthesized by having a single antenna, coupled to a receiver, spatially translated along an arbitrary trajectory. As the antenna is being spatially translated, a data processing means samples the incoming signal based on a clock signal provided by a system clock. By sampling the incoming signal at different times at different spatial locations on the arbitrary trajectory, the system acts as a synthetic antenna array. The different samplings of the incoming signal at different times and positions provide signal diversity gain as well as different readings which can be used to detect an incoming signal. The invention is applicable to detecting a wireless communications signal or a GNSS signal under various conditions. The system may include at least one sensor which can provide data for use in calculating data related to the arbitrary trajectory.

Abstract: A system for estimating parameters of an incoming signal is provided. At least one antenna is coupled to at least one suitable receiver. The antenna(s) are spatially translated in an arbitrary trajectory. As the antenna(s) is being spatially translated, a data processing means samples the incoming signal at set intervals based on a clock signal provided by a system clock. By sampling the incoming signal at different times at different spatial locations on the arbitrary trajectory, the system acts as a synthetic antenna array. The different samplings of the incoming signal at different times and positions provide signal diversity gain as well as different readings which can be used to estimate and/or calculate various parameters of the incoming signal. The different samplings can be used to detect the incoming signal, estimate its angle of arrival, estimate its time of arrival, as well as other parameters.

Abstract: Embodiments of the invention provide a method for effecting Doppler removal and correlation for software-based receivers. For one embodiment of the invention Doppler removal is performed concurrently for all received communications signals. For one embodiment of the invention, a single frequency selected to effect Doppler removal, multiple communications signals having Doppler frequency shift are received from corresponding communications signal sources, and a Doppler removal process is performed concurrently for each received communication signal. A correlation process is then performed, the correlation process having an integration interval divided into multiple sub-intervals.

Abstract: Embodiments of the invention provide a method for effecting Doppler removal and correlation for software-based receivers. For one embodiment of the invention Doppler removal is performed concurrently for all received communications signals. For one embodiment of the invention, a single frequency selected to effect Doppler removal, multiple communications signals having Doppler frequency shift are received from corresponding communications signal sources, and a Doppler removal process is performed concurrently for each received communication signal. A correlation process is then performed, the correlation process having an integration interval divided into multiple sub-intervals.

Abstract: A method and apparatus of processing the received spread spectrum signals using an innovative pre-filtering and multi-correlation differential detection (MCDD) technique is disclosed. The primary embodiment of the invention comprises of a pre-filter and pluralities of complex differential detectors for primary processing of SS signal. Other embodiments of the method and apparatus include pre-filter bank, correlator bank and correlation combiner. More specifically (but not limited to), it is directed towards to the enhancement of acquisition and/or tracking performance of SS receivers.

Abstract: A method and apparatus for acquiring and tracking a BOC signal in a satellite navigation receiver includes a synthesized acquisition test function or a discriminator for code delay provided by combining a BOC autocorrelation function and a BOC/PRN cross-correlation function.