US-12618943-B2 - Global navigation satellite system (GNSS) spoofer protection

US12618943B2US 12618943 B2US12618943 B2US 12618943B2US-12618943-B2

Abstract

Techniques for spoofer protection for GNSS receivers. An example methodology includes receiving one or more characteristics of a detected spoofer signal provided by a GNSS spoofer characterization system. The spoofer signal is transmitted by a GNSS spoofer. The one or more characteristics of the detected spoofer signal may include, for instance, one or more of a direction to the GNSS spoofer, a range to the spoofer, a location of the spoofer, and a code type of the detected spoofer signal. The methodology continues with generating parameters for a simulated GNSS signal that is configured to block the GNSS spoofer and transmitting the simulated GNSS signal in the direction of the GNSS spoofer. The parameters can be generated based on the provided one or more characteristics of the detected spoofer signal.

Inventors

Michael H. Stockmaster

Assignees

BAE SYSTEMS INFORMATION AND ELECTRONIC SYSTEMS INTEGRATION INC.

Dates

Publication Date: 20260505
Application Date: 20240318

Claims (20)

1 . A spoofer protection system for global navigation satellite systems (GNSS), the system comprising: an GNSS spoofer characterization system configured to provide one or more characteristics of a detected spoofer signal transmitted by a GNSS spoofer, wherein the one or more characteristics of the detected spoofer signal include a direction to the GNSS spoofer; a GNSS simulation parameter generator configured to generate parameters for a simulated GNSS signal, the simulated GNSS signal configured to block the GNSS spoofer, the parameters based on the one or more characteristics of the detected spoofer signal; and a GNSS satellite simulator configured to transmit the simulated GNSS signal in the direction of the GNSS spoofer.
2 . The system of claim 1 , wherein the one or more characteristics include a spoofer location, and the GNSS simulation parameter generator includes a transmit power calculator comprising: a distance calculator configured to determine a distance to the GNSS spoofer based on the spoofer location; a free space loss calculator configured to calculate a free space transmission loss to the GNSS spoofer based on the distance; an expected power calculator configured to calculate an expected GNSS signal power for the GNSS spoofer at the spoofer location; and a power adjustment calculator configured to calculate a simulated GNSS signal power, as one of the parameters, based on the free space loss and the expected GNSS signal power for the GNSS spoofer at the spoofer location.
3 . The system of claim 1 , wherein the GNSS simulation parameter generator includes a satellite status generator configured to modify a satellite status field to indicate a problem with the satellite, as one of the parameters.
4 . The system of claim 1 , wherein the GNSS simulation parameter generator includes an invalid data generator configured to set a data validity indicator to an invalid state as one of the parameters.
5 . The system of claim 1 , wherein the GNSS simulation parameter generator includes a false satellite ephemeris generator comprising: a satellite location extractor configured to extract satellite locations from a true satellite ephemeris; a satellite location adjuster configured to add errors to the satellite locations to generate false satellite locations; and an ephemeris reconstructor configured to generate a false satellite ephemeris, as one of the parameters, the false satellite ephemeris including the false satellite locations.
6 . The system of claim 1 , wherein the GNSS simulation parameter generator includes a time error generator configured to introduce timing errors to the detected spoofer signal as one of the parameters.
7 . The system of claim 1 , wherein the GNSS is one of a Global Positioning System or a Galileo satellite system.
8 . The system of claim 1 , wherein the GNSS simulation parameter generator includes one or more processors and one or more processor-readable mediums encoded with instructions that when executed by the one or more processors cause a process to be carried out to generate parameters for a simulated GNSS signal based on the one or more characteristics of the detected spoofer signal.
9 . A computer program product including one or more non-transitory machine-readable mediums encoded with instructions that when executed by one or more processors cause a process to be carried out for spoofer protection for global navigation satellite systems (GNSS), the process comprising: receiving one or more characteristics of a detected spoofer signal from a GNSS spoofer characterization system, the spoofer signal transmitted by a GNSS spoofer, wherein the one or more characteristics of the detected spoofer signal include a direction to the GNSS spoofer; generating parameters for a simulated GNSS signal, the simulated GNSS signal configured to block the GNSS spoofer, the parameters based on the characteristics of the detected spoofer signal; and transmitting the simulated GNSS signal in the direction of the GNSS spoofer.
10 . The computer program product of claim 9 , wherein the one or more characteristics include a spoofer location, the parameters include a simulated GNSS signal power, and the process further comprises: determining a distance to the GNSS spoofer based on the spoofer location; calculating a free space transmission loss to the GNSS spoofer based on the distance; calculating an expected GNSS signal power for the GNSS spoofer at the spoofer location; and calculating a simulated GNSS signal power, as one of the parameters, based on the free space loss and the expected GNSS signal power for the GNSS spoofer at the spoofer location.
11 . The computer program product of claim 9 , wherein the parameters include a satellite vehicle identifier (SVID), and the process further comprises modifying a satellite status field to indicate a problem with the satellite associated with the SVID, as one of the parameters.
12 . The computer program product of claim 9 , wherein the parameters include a data validity indicator, and the process further comprises setting the data validity indicator to an invalid state.
13 . The computer program product of claim 9 , wherein the parameters include a satellite ephemeris, and the process further comprises adding errors to the satellite ephemeris.
14 . The computer program product of claim 9 , wherein the process further comprises introducing timing errors to the detected spoofer signal as one of the parameters.
15 . A method for spoofer protection for global navigation satellite systems (GNSS), the method comprising: receiving one or more characteristics of a detected spoofer signal from a GNSS spoofer characterization system, the spoofer signal transmitted by a GNSS spoofer, wherein the one or more characteristics of the detected spoofer signal include a direction to the GNSS spoofer; generating parameters for a simulated GNSS signal, the simulated GNSS signal configured to block the GNSS spoofer, the parameters based on the one or more characteristics of the detected spoofer signal; and transmitting the simulated GNSS signal in the direction of the GNSS spoofer.
16 . The method of claim 15 , wherein the one or more characteristics include a spoofer location, the parameters include a simulated GNSS signal power, and the method further comprises: determining a distance to the GNSS spoofer based on the spoofer location; calculating a free space transmission loss to the GNSS spoofer based on the distance; calculating an expected GNSS signal power for the GNSS spoofer at the spoofer location; and calculating a simulated GNSS signal power, as one of the parameters, based on the free space loss and the expected GNSS signal power for the GNSS spoofer at the spoofer location.
17 . The method of claim 15 , wherein the parameters include a satellite vehicle identifier (SVID), and the method further comprises modifying a satellite status field to indicate a problem with the satellite associated with the SVID, as one of the parameters.
18 . The method of claim 15 , wherein the parameters include a data validity indicator, and the method further comprises setting the data validity indicator to an invalid state.
19 . The method of claim 15 , wherein the parameters include a satellite ephemeris, and the method further comprises adding errors to the satellite ephemeris.
20 . The method of claim 15 , wherein the method further comprises introducing timing errors to the detected spoofer signal as one of the parameters.

Description

FIELD OF DISCLOSURE The present disclosure relates to global navigation satellite systems (GNSS), and more particularly to spoofer protection for GNSS receivers. BACKGROUND GNSS technology has been adopted into widespread use to provide location, timing, and navigation assistance for countless applications. GNSS includes many types of satellite based navigation systems including, for example, global positioning system (GPS) and Galileo. Many military applications depend on GNSS, for example, to provide targeting of weapons systems and navigation functionality for aircraft, ships, ground vehicles, and ground troops. Unfortunately, GNSS receivers can be spoofed by adversaries. These adversaries may broadcast false GNSS signals that mimic authentic GNSS signals and introduce errors that render the GNSS receivers ineffective. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates an example spoofing scenario of a GNSS receiver. FIG. 2 illustrates an implementation of a GNSS spoofer protection system, configured in accordance with certain embodiments of the present disclosure. FIG. 3 is a block diagram of the GNSS spoofer protection system of FIG. 2, configured in accordance with certain embodiments of the present disclosure. FIG. 4 is a block diagram of a GNSS simulation parameter generator of the GNSS spoofer protection system of FIG. 3, configured in accordance with certain embodiments of the present disclosure. FIG. 5 is a block diagram of a transmit power calculator of the GNSS simulation parameter generator of FIG. 4, configured in accordance with certain embodiments of the present disclosure. FIG. 6 is a block diagram of a false satellite ephemeris generator of the GNSS simulation parameter generator of FIG. 4, configured in accordance with certain embodiments of the present disclosure. FIG. 7 is a flowchart illustrating a methodology for GNSS spoofer protection, in accordance with an embodiment of the present disclosure. FIG. 8 is a block diagram of a processing platform configured to provide GNSS spoofer protection, in accordance with an embodiment of the present disclosure. Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent in light of this disclosure. DETAILED DESCRIPTION Techniques are provided herein for spoofer protection for GNSS receivers. As noted above, GNSS receivers can be spoofed by malicious actors that transmit fake signals which mimic an authentic GNSS signal. Such spoofing, if not detected, can cause a given GNSS receiver to track a false signal and calculate erroneous timing, position, and navigation information. This can potentially be more dangerous to the user of the receiver than simple jamming since the user may not know that the provided information is wrong, whereas a user will more likely know when a receiver is being jammed. Although military grade GNSS receivers generally have some level of spoofing protection, many other GNSS receivers are designed to be small, portable, and low cost, and typically do not possess built in protection capabilities to mitigate the effects of spoofing signals. Adding such protective measures to these receivers would, in many instances, be expensive and impractical. To this end, and in accordance with an embodiment of the present disclosure, a GNSS spoofer protection system is disclosed which neutralizes or otherwise impedes GNSS spoofer systems, thereby providing protection to any number of GNSS receivers, in the geographic area in which the spoofer may otherwise have an impact, and without requiring any modifications to those receivers. In an example, a GNSS spoofer protection system is provided that determines one or more characteristics of the spoofing signal and generates a simulated GNSS signal, using adjusted parameters based on those one or more characteristics. The simulated GNSS signal, or spoofer blocking signal, is then transmitted in the direction or geographic area of the GNSS spoofer. This simulated GNSS signal essentially spoofs the spoofer, causing the spoofer to transmit spoofing signals with invalid or otherwise unusable data that most GNSS receivers will reject in the course of normal operation, allowing them to instead lock on to legitimate GNSS signals broadcast from satellites. In another example, a methodology for providing spoofer protection for GNSS receivers is provided and includes receiving one or more characteristics of a detected spoofer signal that is transmitted by a GNSS spoofer. The one or more characteristics may be provided, for instance, by an anti-jamming GNSS system or a dedicated GNSS spoofer characterization system. The one or more characteristics of the detected spoofer signal may include, for example, one or more of the direction to the GNSS spoofer, the location of the GNSS spoofer, the power level of the received spoofing signal, and the code type of the detected spoofer