A method and apparatus are provided for spoofing detection in the context of a vehicle-based GNSS receiver. An attitude estimate of the vehicle is obtained. A velocity estimate is calculated based on measurements provided by the GNSS receiver. The method comprises projecting the velocity estimate to a body frame of the vehicle, using the attitude estimate; deriving a detection parameter from the projected velocity estimate; and comparing the detection parameter with a detection threshold, in order to detect spoofing.

The present application discloses detecting manipulation of GNSS signals using a second time source. If two or more GNSS constellation signals are being detected, the phase error between the GNSS constellation signals may be monitored. When the phase error drifts, then manipulation is determined. The integrity of a GNSS constellation signal may be monitored using an internal time source such as a crystal oscillator by monitoring a slope of the free running counter at the detected rising edges of a pulse-per-second signal from the GNSS constellation. If more than two GNSS constellations are monitored, a voting scheme may be used to determine the manipulated GNSS constellation.

A technology is described for mitigating global positioning system (GPS) spoofer signals. A potentially spoofed GPS signal received via an antenna coupled to a GPS receiver can be identified. The potentially spoofed GPS signal can be applied to a spoofer signal nulling loop to generate a set of spoofer nulling weights. The set of spoofer nulling weights can produce a direction vector associated with the potentially spoofed GPS signal. The direction vector can be compared to a beamsteering vector. The potentially spoofed GPS signal can be determined as being a spoofer GPS signal when a misalignment between the direction vector and the beamsteering vector is above a defined threshold. The spoofer GPS signal can be converted to a spoofer mitigation signal that is applied to satellite track channels of the GPS receiver. The spoofer mitigation signal can produce a spatial null in a direction of the spoofer GPS signal.

In conditions in which Global Navigation Satellite System (GNSS) signal spoofing is likely occurring, a GNSS receiver may be operated in a reduced operational state with respect to one or more GNSS bands that are likely being spoofed. According to embodiments, a reduced operational state with regard to a GNSS band may comprise performing one or more of the following functions with respect to that GNSS band: disabling data demodulation and decoding, disabling time setting (e.g., time of week (TOW), week number, etc.) disabling acquisition of unknown/not visible satellites, disabling satellite differences, disabling error recovery, reducing non-coherent integration time, and duty cycling the power for one or more receiver blocks associated with the GNSS band.

Techniques for determining whether data associated with an autonomous operation of an unmanned vehicle may be trusted. For example, the data may be analyzed in light of a capability of the unmanned vehicle. The analysis may indicate an operation of the unmanned vehicle. If the operation is unsupported by the capability, the data may be determined to be untrusted. Accordingly, the autonomous navigation may be directed independently of the untrusted data.

Disclosed herein are system, method, and computer program product embodiments for detecting spoofing of a navigation device. A plurality of anti-spoofing techniques are provided. The plurality of anti-spoofing techniques detect interference with data provided by one or more navigation devices for a plurality of threat situations. Positioning, timing and frequency characteristics associated with the one or more navigation devices are analyzed in order to identify a threat situation among the plurality of threat situations. Based on the identified threat situation one or more of the anti-spoofing techniques are executed. The one or more anti-spoofing techniques can be executed in parallel in order to provide various anti-spoofing detection techniques at the same time.

A method for certifying the geolocation of a receiver, including, prior to said certification, receiving, at predetermined times, in addition to the geolocation signals emitted by a plurality of emitters and used to compute said geolocation, a predetermined number of additional electromagnetic signals emitted by the same emitters and including data used to authenticate the geolocation, the method comprising determining the authenticity of the geolocation on the basis of the additional electromagnetic signals.

Technology for determining a geographical location of a ground receiver is disclosed. A plurality of radio frequency (RF) signals from a plurality of RF signal carriers may be received at the ground receiver. The plurality of RF signal carriers may include satellites operated by a foreign entity or non-global positioning system (non-GPS) satellites. The ground receiver may measure a Doppler shift associated with each of the plurality of RF signals. The geographical location of the ground receiver may be determined in X, Y and Z coordinates based in part on the Doppler shift associated with each of the plurality of RF signals.

The invention relates to a method and system for the validation of satellite-based positioning. The system comprises a radio navigation device (10) installed on board a mobile carrier (2), including a satellite geo-positioning device (12) able to receive a composite radio signal including a plurality of radio navigation signals each transmitted by a transmitting satellite and including time-synchronization and position-reference information, the radio navigation device being able to carry out processing of the received radio navigation signals to calculate first navigation information including information on the geographical position, speed and time of the carrier.

The radio navigation device (10) is capable of transmitting baseband digitized signals (IF.sub.1, . . . , IF.sub.N) from radio navigation signals received at the reference processing station (16), the reference processing station (16) is capable of carrying out processing (29) similar to the processing (20), carried out by said radio navigation device (10), of the digitized signals (IF.sub.1, . . . , IF.sub.N) in order to calculate second navigation information, and the system comprises means (22, 42) for validating the first navigation information in accordance with the second navigation information calculated by the reference processing station (16).

A system and method to determine the location of an interfering signal source within a few meters. Three or more networked GNSS receivers are located at known locations and used to simultaneously collect and time-stamp data samples at L1 and L2. The data samples are passed over the network to a server which identifies samples associated with an interfering signal, cross correlates associated samples from pairs of receivers, and applies a discriminator function to significantly improve the accuracy of a computed time difference of arrival (TDOA) for the interfering signal, thereby significantly improving the accuracy of the location determination.