Satellite relaying for geolocation and mitigation of GNSS denial

Patent metadata

Field	Value
Publication number	US-11736946-B2
Application number	US-202117186582-A
Country	US
Kind code	B2
Filing date	Feb 26, 2021
Priority date	Apr 1, 2020
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

According to one or more of the embodiments herein, systems and techniques for satellite relaying for geolocation and mitigation of Global Navigation Satellite System (GNSS) denial are provided. In one embodiment, a method comprises: receiving, at a processing device from a communication satellite along a communication path, a message initiated by a transmitting device and indicating a transmission time, the communication path having a target device with an unknown distance to the communication satellite; determining a reception time upon receiving the message, (the processing device and the transmitting device have synchronized clocks); determining a time difference between the transmission time and the reception time; calculating a distance between the communication satellite and the target device based on a portion of the determined time difference associated with only traversal of a portion of the communication path between the communication satellite and the target device; and performing action(s) based on the distance.

First claim

What is claimed is:

1. A method, comprising:
receiving, by a processing device from a communication satellite along a communication path, a message initiated by a transmitting device, the communication path having a target device with an unknown distance to the communication satellite, the message indicating a transmission time by the transmitting device;
determining, by the processing device, a reception time upon receiving the message, wherein the processing device and the transmitting device have synchronized clocks;
determining, by the processing device, a time difference between the transmission time and the reception time;
calculating, by the processing device, a distance between the communication satellite and the target device, the distance calculated based on a portion of the determined time difference associated with only traversal of a portion of the communication path that is between the communication satellite and the target device; and
performing, by the processing device, one or more actions based on the distance between the communication satellite and the target device,
wherein the processing device and the transmitting device have synchronized clocks based on the processing device and the transmitting device independently using Global Navigation Satellites System (GNSS) timing, the method further comprising:
declaring a potential spoofing of the GNSS and a lack of clock synchronization between the processing device and the transmitting device in response to the calculated distance between the communication satellite and the target device being an impossible distance based on one or more criteria.

2. The method as in claim 1 , wherein the transmitting device is the target device, and wherein the processing device is a ground station.

3. The method as in claim 1 , wherein the transmitting device is a ground station, and wherein the processing device is the target device.

4. The method as in claim 1 , wherein the transmitting device is the communication satellite, and wherein the processing device is the target device, and wherein the communication satellite is configured to send the message as one of a plurality of beacon messages as instructed by a ground station.

5. The method as in claim 4 , wherein the communication satellite receives updated control messages from the ground station regarding configuration of the beacon messages configures one or more adjustable transmission parameters for the initiated message.

6. The method as in claim 5 , wherein the updated control messages from the ground station regarding configuration of the beacon messages configure one or more adjustable transmission parameters for the beacon messages.

7. The method as in claim 1 , wherein the processing device and the transmitting device each have a synchronized atomic clock.

8. The method as in claim 1 , wherein the processing device and the transmitting device have synchronized clocks based on a two-way, common view, time transfer communication mechanism between the processing device and the transmitting device.

9. The method as in claim 8 , wherein one of either the processing device or the transmitting device has an atomic clock.

10. The method as in claim 1 , wherein the transmitting device is the target device, and wherein the communication satellite has a synchronized clock with the transmitting device, wherein the communication satellite marks a time of arrival of the message from the transmitting device at the communication satellite, and wherein determining the reception time comprises using the time of arrival marked by the communication satellite, and wherein calculating the distance between the communication satellite and the target device comprises converting the time difference between the transmission time and the reception time into the distance.

11. The method as in claim 1 , wherein the processing device is the target device, and wherein the communication satellite has a synchronized clock with the processing device, wherein the communication satellite marks a time of transmission of the message from the communication satellite, and wherein the time of transmission of the message from the communication satellite is used as the transmission time for determining the time difference between the transmission time and the reception time, and wherein calculating the distance between the communication satellite and the target device comprises converting the time difference between the transmission time and the reception time into the distance.

12. The method as in claim 1 , wherein determining the portion of the determined time difference associated with only the traversal of the portion of the communication path that is between the communication satellite and the target device is based at least in part on removing any delay incurred by the communication satellite.

13. The method as in claim 12 , wherein the delay is a fixed time and known prior to transmitting the initiated message.

14. The method as in claim 12 , wherein the delay is predetermined by the communication satellite and indicated in the message when sent by the communication satellite.

15. The method as in claim 12 , wherein the delay is indicated in one or more following messages sent by the communication satellite once the delay is calculated by the communication satellite.

16. The method as in claim 1 , wherein determining the portion of the determined time difference associated with only the traversal of the portion of the communication path that is between the communication satellite and the target device is based at least in part on removing portions of the communication path other than the portion of the communication path that is between the communication satellite and the target device.

17. The method as in claim 16 , wherein removing portions of the communication path other than the portion of the communication path that is between the communication satellite and the target device is based on removing a known time associated with the portions of the communication path other than the portion of the communication path that is between the communication satellite and the target device.

18. The method as in claim 16 , wherein removing portions of the communication path other than the portion of the communication path that is between the communication satellite and the target device is based on removing a known distance associated with the portions of the communication path other than the portion of the communication path that is between the communication satellite and the target device.

19. The method as in claim 1 , wherein performing one or more actions based on the distance between the communication satellite and the target device comprises using the distance between the communication satellite and the target device for a location determination of the target device.

20. The method as in claim 19 , wherein the location determination of the target device uses a plurality of distances between the target device and a respective plurality of reference objects for trilateration.

21. The method as in claim 20 , wherein the plurality of reference objects for trilateration comprise additional communication satellites with respective distances to the target device being calculated based on determining a respective time difference between a respective transmission time of additional messages and a respective reception time of the additional messages.

22. The method as in claim 20 , wherein the target device comprises a

Assignees

• Higher Ground Llc

Inventors

• Reis Robert S
• Shaffer Shmuel
• Reis Darren Robert
• Behmke James M
• Reuss David Alexander

Classifications

• G01S19/20

  Integrity monitoring, fault detection or fault isolation of space segment · CPC title

• G01S19/215

  issues related to spoofing · CPC title

• G01S19/21 Primary

  Interference related issues {; Issues related to cross-correlation, spoofing or other methods of denial of service} · CPC title

• G01S19/421

  by combining or switching between position solutions or signals derived from different satellite radio beacon positioning systems; by combining or switching between position solutions or signals derived from different modes of operation in a single system · CPC title

• H04W12/122 Primary

  Counter-measures against attacks; Protection against rogue devices · CPC title