Abstract: Improvements in Global Navigation Satellite System (GNSS) spoofing detection of a vehicle are disclosed utilizing bearing and/or range measurements acquired independently from GNSS technology. Bearing and/or range measurements are determined from a GNSS-calculated position. Additionally, bearing and/or range measurements are acquired from an independent sensor, such as a Radio Detection and Ranging (radar) and a terrain database. The differences between the GNSS-based bearing and/or range and the bearing and/or range determined from the independent sensor, along with any applicable sources of error or uncertainty (including the post-hoc residuals from the GNSS-calculated position), are input into an analytical algorithm (e.g., RAIM) to determine whether GNSS spoofing is present with respect to the calculated GNSS position. If spoofing is detected, an alternative position determining system can be used in lieu of GNSS technology, and alerts can be sent notifying appropriate entities of the spoofing result.

Abstract: A method comprises receiving an ILS transmission signal in an onboard ILS receiver during an aircraft approach, and receiving a GNSS position signal in an onboard GNSS augmentation system receiver during the approach. The method determines a first set of flight path deviations based on the ILS transmission signal, and a second set of flight path deviations based on the GNSS position signal. The first set of flight path deviations are sent to a first complementary filter, which outputs a first filtered deviations signal. The second set of flight path deviations is sent to a second complementary filter, which outputs a second filtered deviations signal. A scale factor is applied to the first filtered deviations signal or the second filtered deviations signal, such that the filtered deviations signals are normalized to the same scale. The method combines the normalized filtered deviations signals to produce a hybrid signal for further processing.

Abstract: Improvements in Global Navigation Satellite System (GNSS) spoofing detection of a vehicle are disclosed utilizing bearing and/or range measurements acquired independently from GNSS technology. Bearing and/or range measurements are determined from a GNSS-calculated position. Additionally, bearing and/or range measurements are acquired from an independent sensor, such as a Very high frequency Omnidirectional Range (VOR) receiver and/or a Distance Measurement Equipment (DME) receiver. The differences between the GNSS-based bearing and/or range and the bearing and/or range determined from the independent sensor, along with any applicable sources of error or uncertainty (including the post-hoc residuals from the GNSS-calculated position), are input into an analytical algorithm (e.g., RAIM) to determine whether GNSS spoofing is present with respect to the calculated GNSS position.

Abstract: Improvements in Global Navigation Satellite System (GNSS) spoofing detection of a vehicle are disclosed utilizing bearing and/or range measurements acquired independently from GNSS technology. Bearing and/or range measurements are determined from a GNSS-calculated position. Additionally, bearing and/or range measurements are acquired from an independent sensor, such as a Radio Detection and Ranging (radar) and a terrain database. The differences between the GNSS-based bearing and/or range and the bearing and/or range determined from the independent sensor, along with any applicable sources of error or uncertainty (including the post-hoc residuals from the GNSS-calculated position), are input into an analytical algorithm (e.g., RAIM) to determine whether GNSS spoofing is present with respect to the calculated GNSS position. If spoofing is detected, an alternative position determining system can be used in lieu of GNSS technology, and alerts can be sent notifying appropriate entities of the spoofing result.

Abstract: Improvements in Global Navigation Satellite System (GNSS) spoofing detection of a vehicle are disclosed utilizing bearing and/or range measurements acquired independently from GNSS technology. Bearing and/or range measurements are determined from a GNSS-calculated position. Additionally, bearing and/or range measurements are acquired from an independent sensor, such as a Very high frequency Omnidirectional Range (VOR) receiver and/or a Distance Measurement Equipment (DME) receiver. The differences between the GNSS-based bearing and/or range and the bearing and/or range determined from the independent sensor, along with any applicable sources of error or uncertainty (including the post-hoc residuals from the GNSS-calculated position), are input into an analytical algorithm (e.g., RAIM) to determine whether GNSS spoofing is present with respect to the calculated GNSS position.

Abstract: A system comprises processing circuitry configured to receive position data from a global navigation satellite system (GNSS) receiver and to receive a first vehicle height above terrain (HAT) from HAT circuitry. A lateral position and an altitude are derived from the position data. The processing circuitry is further configured to determine terrain elevation based upon the lateral position. The processing circuitry is further configured to determine a second vehicle height above terrain (HAT) based upon subtracting the determined terrain elevation from the altitude. The processing circuitry is further configured to detect GNSS spoofing based upon a difference between the first vehicle HAT and the second vehicle HAT; and upon detecting GNSS spoofing, issue an alert.

Abstract: A method comprises receiving an ILS transmission signal in an onboard ILS receiver during an aircraft approach, and receiving a GNSS position signal in an onboard GNSS augmentation system receiver during the approach. The method determines a first set of flight path deviations based on the ILS transmission signal, and a second set of flight path deviations based on the GNSS position signal. The first set of flight path deviations are sent to a first complementary filter, which outputs a first filtered deviations signal. The second set of flight path deviations is sent to a second complementary filter, which outputs a second filtered deviations signal. A scale factor is applied to the first filtered deviations signal or the second filtered deviations signal, such that the filtered deviations signals are normalized to the same scale. The method combines the normalized filtered deviations signals to produce a hybrid signal for further processing.

Abstract: A system comprises processing circuitry configured to receive position data from a global navigation satellite system (GNSS) receiver and to receive a first vehicle height above terrain (HAT) from HAT circuitry. A lateral position and an altitude are derived from the position data. The processing circuitry is further configured to determine terrain elevation based upon the lateral position. The processing circuitry is further configured to determine a second vehicle height above terrain (HAT) based upon subtracting the determined terrain elevation from the altitude. The processing circuitry is further configured to detect GNSS spoofing based upon a difference between the first vehicle HAT and the second vehicle HAT; and upon detecting GNSS spoofing, issue an alert.

Abstract: A system to select a type of satellite from a plurality of types of satellites in a multi-constellation of satellites is provided. The system includes at least a first receiver configured to input signals from a first type of satellite and a second receiver configured to input signals from a second type of satellite and a processor. The processor: executes a multi-constellation-selection software module to associate a current position with a mapping feature and select at least one selected type of satellite from the plurality of types of satellites based on the associated mapping feature; executes a compute-position/velocity/time (PVT) software module to compute a current position/velocity/time based on at least one selected input signal input at a receiver associated with the at least one selected type of satellite; and feeds the computed current position/velocity/time to the multi-constellation-selection software module based on the execution of the compute-PVT software module.

Abstract: A system to select a type of satellite from a plurality of types of satellites in a multi-constellation of satellites is provided. The system includes at least a first receiver configured to input signals from a first type of satellite and a second receiver configured to input signals from a second type of satellite and a processor. The processor: executes a multi-constellation-selection software module to associate a current position with a mapping feature and select at least one selected type of satellite from the plurality of types of satellites based on the associated mapping feature; executes a compute-position/velocity/time (PVT) software module to compute a current position/velocity/time based on at least one selected input signal input at a receiver associated with the at least one selected type of satellite; and feeds the computed current position/velocity/time to the multi-constellation-selection software module based on the execution of the compute-PVT software module.