Satellite echoing for geolocation and mitigation of GNSS denial

Patent metadata

Field	Value
Publication number	US-11770714-B2
Application number	US-202117186552-A
Country	US
Kind code	B2
Filing date	Feb 26, 2021
Priority date	Apr 1, 2020
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

Satellite echoing for geolocation and mitigation of Global Navigation Satellite System (GNSS) denial are provided herein, where an example method comprises: transmitting an initiated message to a communication satellite along a communication path that has a target device with an unknown distance to the communication satellite; receiving a returned message from the communication satellite over the communication path in response to the initiated message; determining a local time difference between the transmission time and the reception time; calculating 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 a single traversal of a portion of the communication path that is between the communication satellite and the target device; and performing one or more actions based on the distance between the communication satellite and the target device.

First claim

What is claimed is:

1. A method, comprising:
transmitting, by a processing device at a transmission time local to the processing device, an initiated message to a communication satellite along a communication path that has a target device with an unknown distance to the communication satellite;
receiving, by the processing device at a reception time local to the processing device, a returned message from the communication satellite over the communication path in response to the initiated message;
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 a single 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.

2. The method as in claim 1 , wherein determining the portion of the determined time difference associated with only the single 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 node-incurred delay along the communication path.

3. The method as in claim 2 , wherein the node-incurred delay is a fixed time and known prior to transmitting the initiated message.

4. The method as in claim 2 , wherein the node-incurred delay is indicated in the returned message.

5. The method as in claim 4 , wherein the node-incurred delay is set by the communication satellite.

6. The method as in claim 2 , wherein the node-incurred delay is indicated in one or more following messages received by the processing device after the returned message once the node-incurred delay is calculated by one or more nodes along the communication path.

7. The method as in claim 1 , wherein determining the portion of the determined time difference associated with only the single 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.

8. The method as in claim 7 , 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.

9. The method as in claim 7 , 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.

10. 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.

11. The method as in claim 10 , 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.

12. The method as in claim 11 , 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 initiated messages and a respective reception time of corresponding returned messages.

13. The method as in claim 11 , wherein the target device comprises a directional antenna, and wherein the target device aims separately at one or more of the plurality of reference objects.

14. The method as in claim 11 , wherein the plurality of reference objects for trilateration are based on a plurality of different location determination hardware systems.

15. The method as in claim 14 , wherein at least one of the plurality of different location determination hardware systems is a Global Navigation Satellite System (GNSS) and wherein at least one of the plurality of reference objects for trilateration is a GNSS satellite.

16. The method as in claim 14 , wherein at least one of the plurality of distances is between the target device and a geolocated object having a known location based on a Global Navigation Satellite System (GNSS).

17. The method as in claim 11 , wherein the target device comprises a directional antenna, and wherein the target device aims the directional antenna singularly at the communication satellite and communicates with one or more other communication satellites as reference objects based on adjacent satellite interference (ASI) spillover from the directional antenna for corresponding additional distances between the target device and the one or more other communication satellites.

18. The method as in claim 17 , wherein the target device is the processing device, and wherein the one or more other communication satellites communicate with the communication satellite to which the target device aims as a primary communication satellite, and wherein the one or more other communication satellites are time synchronized with the target device, and wherein the one or more other communication satellites create a respective timestamp upon reception of the initiated message and communicate the respective timestamp to the primary communication satellite for return to the target device.

19. The method as in claim 11 , wherein at least one of the plurality of reference objects is selected based on minimizing geometric dilution of precision (GDOP) of the location determination based on the plurality of reference objects.

20. The method as in claim 11 , wherein the plurality of reference objects for trilateration includes two communication satellites and a separate altitude determination mechanism.

21. The method as in claim 1 , wherein the processing device is the target device.

22. The method as in claim 21 , wherein calculating the distance between the communication satellite and the target device comprises:
determining a delay incurred by the communication satellite;
subtracting the delay from the determined time difference to produce a time of flight value; and
separating the single traversal of the portion of the communication path that is between the communication satellite and the target device from the total time of flight value for the communication path by a process selected from a group consisting of:
a) dividing the time of flight value in half to produce the portion of the determined time difference associated with only the single traversal of the portion of the communication path that is between the communication satellite and the target device, and converting the portion of the determined time difference associated with only the single traversal of the portion of the communication pa

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

• H04W12/122 Primary

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

• G01S5/14

  Determining absolute distances from a plurality of spaced points of known location · CPC title

• G01S19/115

  Airborne or satellite based pseudolites or repeaters · CPC title