SYSTEM AND METHOD FOR DETERMINING THE DIRECTION OF A FALSE GNSS SATELLITE SIGNAL TRANSMITTER

• US 20150268350A1
• Filed: 03/12/2015
• Published: 09/24/2015
• Est. Priority Date: 08/14/2013
• Status: Active Grant

• Current Assignee: Hemisphere GNSS(USA) Incorporated
• Original Assignee: Hemisphere GNSS(USA) Incorporated
• Inventors: WHITEHEAD, MICHAEL
• Granted Patent: US 10,234,564 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01S 19/215 issues related to spoofing
• CPC Class Codes: G01S 3/46 using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems

Abstract

Disclosed is a device and method for determining the direction of a false Global Navigation Satellite System (GNSS) satellite signal transmitter. False GNSS satellite signals can be used malevolently to take control of a rigid body such as a vehicle or ship that is using GNSS satellite signals for navigation. The GNSS device according to the invention computes a plurality of range differences, where each range difference is the difference between a range from a first GNSS satellite to a first GNSS antenna, and the range from the first GNSs satellite to a second GNSS antenna. Each of the plurality of range differences is correlated to a rotation angle of a baseline vector extending from the first GNSS antenna to the second GNSS antenna. The rotation angles and their corresponding range differences can be used to indicate the direction of the false GNSS satellite signal transmitter.

Claims

1. A method of using a global navigation satellite system (GNSS) attitude system to determine a direction of a false GNSS satellite signal transmitter comprising:

calculating a plurality of range differences;

and

determining the direction of the false GNSS satellite signal transmitter based on the plurality of range differences.

2. The method of claim 1, wherein each one of the plurality of range differences corresponds to a baseline vector rotation angle.

3. The method of claim 2, wherein the baseline vector rotation angle is measured with respect to a fixed reference body.

4. The method of claim 3, wherein calculating the plurality of range differences comprises:

calculating a first range from a first GNSS satellite signal received by a first GNSS antenna;

calculating a second range from the first GNSS satellite signal received by a second GNSS antenna, wherein a baseline vector extends from the first GNSS antenna to the second GNSS antenna;

and

calculating a first range difference by subtracting the first range from the second range.

5. The method of claim 3, wherein determining the direction of the false GNSS satellite signal transmitter based on the plurality of range differences comprises:

identifying a maximum baseline vector rotation angle, wherein the maximum baseline vector rotation angle comprises a baseline vector rotation angle that corresponds to a maximum value of range difference;

and

setting the direction of the false GNSS satellite signal transmitter to be equal to the maximum baseline vector rotation angle plus 180 degrees.

6. The method of claim 3, wherein determining the direction of the false GNSS satellite signal transmitter based on the plurality of range differences comprises:

identifying a minimum baseline vector rotation angle, wherein the minimum baseline vector rotation angle comprises a baseline vector rotation angle that corresponds to a minimum value of range difference;

and

setting the direction of the false GNSS satellite signal transmitter to be equal to the minimum baseline vector rotation angle.

7. The method of claim 1, wherein determining the direction of the false GNSS satellite signal transmitter based on the plurality of range differences comprises calculating a path difference distance for each one of the plurality of range differences.

8. The method of claim 1, wherein determining the direction of the false GNSS satellite signal transmitter based on the plurality of range differences comprises computing the travel time differential bias for each one of the plurality of range differences.

9. The method of claim 1, further comprising detecting that a false GNSS satellite signal is being received.

10. The method of claim 1, further comprising indicating the direction of the false GNSS satellite signal transmitter.

11. A method of determining a direction of a false Global Navigation Satellite System (GNSS) satellite signal transmitter comprising:

rotating a baseline vector through a plurality of rotation angles, wherein the plurality of rotation angles are measured with respect to a fixed reference body;

calculating a plurality of range differences, wherein each one of the plurality of range differences corresponds to one of the plurality of rotation angles;

and

determining the direction of the false GNSS satellite signal transmitter based on the plurality of range differences.

12. The method of claim 11, wherein the baseline vector extends from a first GNSS antenna to a second GNSS antenna.

13. The method of claim 12, wherein rotating the baseline vector through the plurality of rotation angles comprises rotationally moving the second GNSS antenna around the first GNSS antenna.

14. The method of claim 13, wherein the first GNSS antenna is in a location that is fixed with respect to the fixed reference body.

15. The method of claim 12, wherein rotating the baseline vector through the plurality of rotation angles comprises rotationally moving the first and the second GNSS antenna around a center point, wherein the baseline vector extends through the center point.

16. The method of claim 15, wherein the center point is fixed in location with respect to the fixed reference body.

17. A global navigation satellite system (GNSS) device for determining the direction of a false GNSS satellite signal transmitter comprising:

a device body, wherein the device body has a direction axis;

a first antenna;

a second antenna;

and

a rotation apparatus, wherein the rotation apparatus moves the second antenna such that a baseline vector extending from the first antenna to the second antenna rotates through a plurality of baseline vector rotation angles, wherein the baseline vector rotation angles are measured with respect to the direction axis.

18. The GNSS device of claim 17, further comprising a processor, wherein the processor computes a plurality of range differences, wherein each one of the plurality of range differences corresponds to one of the plurality of baseline vector rotation angles.

19. The GNSS device of claim 18, wherein the processor determines which one of the plurality of baseline vector rotation angles corresponds to a maximum range difference.

20. The GNSS device of claim 19, wherein the processor outputs a false GNSS satellite signal transmitter direction.

21. The GNSS device of claim 18, wherein the processor determines which one of the plurality of baseline vector rotation angles corresponds to a minimum range difference.

22. A global navigation satellite system (GNSS) device for determining the direction of a false GNSS satellite signal transmitter comprising:

a device body, wherein the device body has a direction axis;

a plurality of GNSS antenna pairs;

wherein one of a plurality of baseline vectors extends between each one of the plurality of GNSS antenna pairs, and wherein each one of the plurality of baseline vectors comprises one of a plurality of baseline vector rotation angles with respect to the direction axis;

and

a processor, wherein the processor performs the following;

calculating a plurality of range differences, wherein each one of the plurality of range differences corresponds to one of the plurality of baseline vector rotation angles;

and

determining the direction of the false GNSS satellite signal transmitter based on the plurality of range differences.