Abstract: Systems and methods for fault detection, exclusion, isolation, and re-configuration of navigation sensors using an abstraction layer are provided. In certain embodiments, a system includes a plurality of sensors that provide redundant sensor measurements, wherein redundancy of the redundant sensor measurements is achieved based on an independence between measurements from different physical sensor units in the plurality of sensors. The system additionally includes a fusion function configured to receive the redundant sensor measurements from each sensor in the plurality of sensors and calculate fused navigation parameters. Further, the system includes an abstraction layer that calculates an estimated state based on the fused navigation parameters, wherein the estimated state comprises safety assessment information for the fused navigation parameters and the fused navigation parameters.

Abstract: Systems and methods for GNSS spoofing detection using C/No based monitoring are provided. In certain embodiments, a system including at least one GNSS receiver that provides C/No for GNSS signals received from GNSS satellites. The system also includes a processor coupled to the at least one GNSS receiver. The processor executes instructions that cause the processor to calculate new C/No comparison values based on the C/No measurements and previous C/No comparison values. Further, the instructions cause the processor to compare the C/No measurements against the previous C/No comparison values. Moreover, the instructions cause the processor to determine whether one or more of the GNSS signals are spoofed based on the comparison of the C/No measurements against the previous C/No comparison values. Additionally, the instructions cause the processor to set the new C/No comparison values as the previous C/No comparison values.

Abstract: Techniques for detecting GNSS spoofing using inertial mixing data are disclosed. One or more navigation parameters are determined by at least one GNSS receiver and a plurality of IRS from at least two periods of time. The navigation parameters from the GNSS receiver(s) and the IRS are compared at each time period, and the difference(s) between the compared navigation parameters are further compared to generate at least one differential value. A system can detect GNSS spoofing by comparing the at least one differential value to a suitable threshold. In one aspect each IRS navigation parameter is compared with a corresponding GNSS navigation parameter, wherein the plurality of differential values is mixed before threshold comparison. In another aspect, each IRS navigation parameter is mixed before comparison with a GNSS navigation parameter, and the resulting differential value is then compared against a threshold.

Abstract: A spoofing detection system including at least one antenna, a receiver and a controller is provided. The at least one receiver is in communication with the at least one antenna to receive detected satellite signals. The controller is configured to determine raw pseudorange values from the received satellite signals. The controller is further configured to apply at least one first filter on the raw pseudorange values to generate at least an output of first filtered pseudorange values. The controller is also conjured to compare an output of the first filtered pseudorange values with one of the raw pseudorange values and second filtered pseudorange values from a second filter. The controller is further configured to determine if spoofing is present in the received satellite signals based on a determined divergence between the output of first filtered pseudorange values and one of the raw pseudorange values and the second filtered pseudorange values.

Abstract: Systems and methods for integrity monitoring of primary and derived parameters are described herein. In certain embodiments, a method includes transforming an estimated error state covariance matrix of at least one primary integrity monitoring parameter of a navigation system onto an error state covariance matrix of one or more derived integrity monitoring parameters, wherein the one or more derived integrity monitoring parameters depends from the at least one primary integrity monitoring parameter. The method also includes transforming an integrity threshold of the at least one primary integrity monitoring parameter onto separation parameters of the one or more derived integrity monitoring parameters. The method further includes computing a protection limit for the one or more derived integrity monitoring parameters.

Abstract: Techniques for detecting GNSS spoofing using inertial mixing data are disclosed. One or more navigation parameters are determined by at least one GNSS receiver and a plurality of IRS from at least two periods of time. The navigation parameters from the GNSS receiver(s) and the IRS are compared at each time period, and the difference(s) between the compared navigation parameters are further compared to generate at least one differential value. A system can detect GNSS spoofing by comparing the at least one differential value to a suitable threshold. In one aspect each IRS navigation parameter is compared with a corresponding GNSS navigation parameter, wherein the plurality of differential values is mixed before threshold comparison. In another aspect, each IRS navigation parameter is mixed before comparison with a GNSS navigation parameter, and the resulting differential value is then compared against a threshold.

Abstract: Systems and methods for fault detection, exclusion, isolation, and re-configuration of navigation sensors using an abstraction layer are provided. In certain embodiments, a system includes a plurality of sensors that provide redundant sensor measurements, wherein redundancy of the redundant sensor measurements is achieved based on an independence between measurements from different physical sensor units in the plurality of sensors. The system additionally includes a fusion function configured to receive the redundant sensor measurements from each sensor in the plurality of sensors and calculate fused navigation parameters. Further, the system includes an abstraction layer that calculates an estimated state based on the fused navigation parameters, wherein the estimated state comprises safety assessment information for the fused navigation parameters and the fused navigation parameters.

Abstract: System and methods are described that illustrate how to collect and store data about geographic regions of jamming and/or spoofing of signal(s) emitted from satellite(s) of a global navigation satellite system (GNSS). An entity is configured to, and to communicate whether the jamming and/or spoofing has been detected, and the corresponding geographic location and the corresponding detection time. A processing system is configured to receive data about detected jamming and/or spoofing, and a corresponding geographic location and a detection time of such jamming and/or spoofing. Entities(s) may receive information about jamming and/or spoofing from the processing system. The received information may be used to alert the entities to dynamically changing jamming and/or spoofing. The received information may be further used so alert other entities to dynamically changing jamming and/or spoofing.

Abstract: A system for detecting satellite signal spoofing using error state estimates is provided. The system includes at least one satellite receiver to receive satellite signals, at least one memory and at least one controller. The at least one memory is configured to store at least operation instructions. The at least one controller is in communication with the at least one satellite receiver and the at least one memory. The at least one controller is configured to determine state estimates from the received satellite signals. The at least one controller is further configured to determine error state estimates based at least in part on differences in current state estimates and differences in delayed state estimates. The controller further configured to determine if spoofing is occurring in one more of the received satellite signals when the error state estimates are greater than a select threshold.

Abstract: A spoofing detection system including at least one antenna, a receiver and a controller is provided. The at least one receiver is in communication with the at least one antenna to receive detected satellite signals. The controller is configured to determine raw pseudorange values from the received satellite signals. The controller is further configured to apply at least one first filter on the raw pseudorange values to generate at least an output of first filtered pseudorange values. The controller is also conjured to compare an output of the first filtered pseudorange values with one of the raw pseudorange values and second filtered pseudorange values from a second filter. The controller is further configured to determine if spoofing is present in the received satellite signals based on a determined divergence between the output of first filtered pseudorange values and one of the raw pseudorange values and the second filtered pseudorange values.

Abstract: Systems and methods for GNSS spoofing detection using C/No based monitoring are provided. In certain embodiments, a system including at least one GNSS receiver that provides C/No for GNSS signals received from GNSS satellites. The system also includes a processor coupled to the at least one GNSS receiver. The processor executes instructions that cause the processor to calculate new C/No comparison values based on the C/No measurements and previous C/No comparison values. Further, the instructions cause the processor to compare the C/No measurements against the previous C/No comparison values. Moreover, the instructions cause the processor to determine whether one or more of the GNSS signals are spoofed based on the comparison of the C/No measurements against the previous C/No comparison values. Additionally, the instructions cause the processor to set the new C/No comparison values as the previous C/No comparison values.

Abstract: A method for computing and applying alternative uncertainty limits is provided. The method includes generating a main solution from a plurality of received measurement signals. A solution separation is applied using a filter bank to generate sub-solutions from the received plurality of measurement signals. Each sub-solution uses all of the measurement signals from the plurality of measurement signals except one measurement signal to generate the associated sub-solution. Each sub-solution excludes a different measurement signal. One sub-solution is selected as fault free. A difference between the main solution and the selected sub-solution is determined. The determined difference is added to a rare normal protection limit to create a solution with improved integrity bounding. The solution with improved integrity bounding is then implemented.

Abstract: Systems and methods for integrity monitoring of primary and derived parameters are described herein. In certain embodiments, a method includes transforming an estimated error state covariance matrix of at least one primary integrity monitoring parameter of a navigation system onto an error state covariance matrix of one or more derived integrity monitoring parameters, wherein the one or more derived integrity monitoring parameters depends from the at least one primary integrity monitoring parameter. The method also includes transforming an integrity threshold of the at least one primary integrity monitoring parameter onto separation parameters of the one or more derived integrity monitoring parameters. The method further includes computing a protection limit for the one or more derived integrity monitoring parameters.

Abstract: A method for computing and applying alternative uncertainty limits is provided. The method includes generating a main solution from a plurality of received measurement signals. A solution separation is applied using a filter bank to generate sub-solutions from the received plurality of measurement signals. Each sub-solution uses all of the measurement signals from the plurality of measurement signals except one measurement signal to generate the associated sub-solution. Each sub-solution excludes a different measurement signal. One sub-solution is selected as fault free. A difference between the main solution and the selected sub-solution is determined. The determined difference is added to a rare normal protection limit to create a solution with improved integrity bounding. The solution with improved integrity bounding is then implemented.

Abstract: Systems and methods for using multi frequency satellite measurements to mitigate spatial decorrelation errors caused by ionosphere delays are provided. In one embodiment, a GBAS comprises: a plurality of GNSS reference receivers that receive signals from GNSS satellites; at least one processing module; at least one aircraft communication device; wherein the processing module determines a TEC along a line of sight of a first observable multi-frequency GNSS satellite to determine a current quality metric of the ionosphere; determines at least one overbounded Vertical Ionosphere Gradient standard deviation sigma-vig (?vig) when the current quality metric of the ionosphere meets a threshold; defines one or more valid iono regions at a given finite period in time where at least one ?vig is applicable; and causes the communication device to communicate to an aircraft the ?vig and a list of GNSS single and multi-frequency satellites having pierce points in the valid iono regions.

Abstract: A method of using space based augmentation system (SBAS) ephemeris data in conjunction with a ground based augmentation systems (GBAS) station is provided. The method includes integrating a space based augmentation system (SBAS) receiver in the GBAS station; receiving an industry-standard message type via the SBAS receiver at the GBAS station; consuming, at the GBAS station, the SBAS ephemeris data from the industry-standard message type associated with satellites in view of the GBAS station. The industry-standard message type includes SBAS ephemeris data associated with satellites in a global navigation satellite system (GNSS). The method further includes, based on the consuming, improving error bounds to GBAS broadcast ephemeris decorellation parameters broadcast from the GBAS station and reducing time to reintroduce a satellite in the GNSS.

Abstract: A system to mitigate errors in GPS corrections and ephemeris uncertainty data broadcast to a vehicle is presented. The system includes reference receivers in a first ground subsystem and a processor. The processor: receives, from reference receivers in a wide area network of reference receivers, satellite measurement data for a first plurality of satellites and receives, from the reference receivers in the first ground subsystem, satellite measurement data and ephemeris data from a second plurality of satellites; evaluate the satellite measurement data to determine if the GPS corrections are degraded by a current ionosphere disturbance activity; determine a current quality metric of the ionosphere; adjust a Vertical Ionosphere Gradient standard deviation sigma-vig; evaluate the ephemeris data to determine if the GPS corrections provided to the vehicle are degraded by ephemeris errors; and establish ephemeris uncertainty to protect integrity based on the evaluation of the ephemeris data.

Abstract: A ground-based system to reduce the effect of interference, comprising a plurality of reference receivers, wherein the reference receivers are spaced a distance apart such that a single source of interference is unable to substantially interfere with a subset of the plurality of reference receivers, wherein the subset of the plurality of reference receivers includes at least two reference receivers; and a processing module communicatively coupled to the plurality of reference receivers and configured to receive data from each of the plurality of reference receivers, wherein the processing module is further configured to perform differential calculations on the data to calculate measurement corrections and estimated errors.

Abstract: GBAS includes reference receivers, processing module, and communication device. Processing module checks GNSS satellite measurements to determine proximity of GNSS satellite measurement's IPP to IGPs derived from SBAS geostationary satellites. Processing module determines that GNSS satellite measurement is safe for mitigation using overbounded Vertical Ionosphere Gradient standard deviation sigma-vig (?vig) when IGPs possess acceptable GIVE values. Processing module determines whether number of GNSS satellite measurements determined safe for mitigation using ?vig are able to produce VPL that meets VAL required for precision approach.

Abstract: A Ground-Based Augmentation System (GBAS) includes a plurality of Global Navigation Satellite System (GNSS) reference receivers configured to receive and process GNSS satellite measurements.