Position and motion informed navigation system

Patent metadata

Field	Value
Publication number	US-11353596-B2
Application number	US-201916414666-A
Country	US
Kind code	B2
Filing date	May 16, 2019
Priority date	Aug 6, 2014
Publication date	Jun 7, 2022
Grant date	Jun 7, 2022

Abstract

A global positioning system (GPS) receiver and system for determining a geographical location associated with the GPS receiver using less than four GPS signals. The system can comprise a constraint module configured to receive one or more constraints that describe at least one characteristic of a GPS receiver when a number of GPS satellites within a line of sight to the GPS receiver is below a defined value. The system can further comprise a pseudo range calculation module configured to calculate a plurality of pseudo ranges between the GPS receiver and the number GPS satellites, wherein the plurality of pseudo ranges are to various orbital positions of the GPS satellites over a period of time; and a geographical location module configured to determine the geographical location of the GPS receiver using the plurality of pseudo ranges and known constraints of motion associated with the GPS receiver.

First claim

What is claimed is:

1. A GPS receiver having computer circuitry configured to:
receive a number of global positioning system (GPS) signals from fewer than four GPS satellites;
inform a user, via a user interface operable with the GPS receiver, that the number of GPS satellites in the line of sight of to the GPS receiver is insufficient for determination of the geographical location of the GPS receiver;
receive, from the user via the user interface, one or more constraints that describe at least one characteristic of the GPS receiver's motion or position, wherein the one or more constraints reduce a number of unknown variables to be solved by the GPS receiver for determination of a geographical location of the GPS receiver using the number of GPS signals from the fewer than four GPS satellites;
inform the user via the user interface that the received one or more constraints are insufficient for determination of the geographical location of the GPS receiver; and
provide at least one recommendation for the user to implement associated with one or more constraints;
calculate a plurality of pseudo ranges between the GPS receiver and the fewer than four GPS satellites; and
determine the geographical location of the GPS receiver using the plurality of pseudo ranges and the one or more recommended constraints.

2. The GPS receiver of claim 1 , wherein the computer circuitry is further configured to prompt the user to input, via the user interface, information associated with the one or more constraints.

3. The GPS receiver of claim 1 , wherein the computer circuitry is further configured to:
calculate an estimated accuracy of the geographical location based on a number of GPS signals received from the fewer than four GPS satellites, a clock type associated with the GPS receiver, and the one or more constraints; and
provide the estimated accuracy of the geographical location to the user via the user interface.

4. The GPS receiver of claim 3 , wherein the computer circuitry is further configured to receive at least one additional constraint from the user via the user interface to improve the estimated accuracy of the geographical location of the GPS receiver.

5. The GPS receiver of claim 1 , wherein the computer circuitry is further configured to display a request to the user via the user interface to constrain an aspect of motion of the GPS receiver.

6. The GPS receiver of claim 1 , wherein the computer circuitry is further configured to display a menu to the user via the user interface of suggestions associated with one or more constraints for implementation by the user.

7. The GPS receiver of claim 1 , wherein the computer circuitry is further configured to inform the user, via the user interface, of a time estimation associated with timing for determination of the geographical location of the GPS receiver.

8. The GPS receiver of claim 1 , wherein the one or more constraints are associated with a hierarchy of constraints corresponding to a minimum number of GPS satellites of the fewer than four GPS satellites that are required for determination of the geographical location of the GPS receiver, and wherein the type of one or more constraints received from the user via the user interface are requested based on the hierarchy of constraints and the number of available GPS satellites.

9. A method for determining a geographical location of a GPS receiver via user interaction, the method comprising:
determining that a number of global positioning system (GPS) satellites within a line of sight to a GPS receiver is fewer than four GPS satellites;
informing a user, via a user interface operable with the GPS receiver, that the number of GPS satellites in the line of sight of to the GPS receiver is insufficient for determination of the geographical location of the GPS receiver;
prompting the user to input, via the user interface, information associated with one or more constraints that describe at least one characteristic of the GPS receiver's position or motion, wherein prompting the user further comprises requesting the user to input certain one or more constraints based on a hierarchy of constraints corresponding to a minimum number of GPS satellites of the fewer than four GPS satellites that are required for determination of a geographical location of the GPS receiver;
receiving the one or more constraints, wherein the one or more constraints reduce a number of unknown variables to be solved by the GPS receiver for determination of the geographical location of the GPS receiver using the number of GPS signals from the fewer than four GPS satellites;
calculating a plurality of pseudo ranges between the GPS receiver and the fewer than four GPS satellites; and
determining the geographical location of the GPS receiver using the plurality of pseudo ranges and the one or more constraints.

10. The method of claim 9 , further comprising displaying a request to the user via the user interface to constrain an aspect of motion of the GPS receiver.

11. The method of claim 9 , further comprising providing a menu to the user via the user interface of suggestions associated with one or more constraints for implementation by the user.

12. The method of claim 9 , further comprising informing the user via the user interface of a time estimation associated with timing of determination of the geographical location of the GPS receiver.

13. A GPS receiver having computer circuitry configured to:
receive a number of global positioning system (GPS) signals from fewer than four GPS satellites;
receive one or more constraints that describe at least one characteristic of the GPS receiver's motion or position, wherein the one or more constraints reduce a number of unknown variables to be solved by the GPS receiver for determination of a geographical location associated with the GPS receiver using the number of GPS signals from the fewer than four GPS satellites, and wherein the one or more constraints are associated with a hierarchy of constraints corresponding to a minimum number of GPS satellites of the fewer than four GPS satellites that are required for determination of the geographical location of the GPS receiver;
calculate a first pseudo range at a first time and orbital position of a first GPS satellite of the fewer than four GPS satellites; and
determine the geographical location of the GPS receiver using the first pseudo range and the one or more constraints.

14. The GPS receiver of claim 13 , wherein the computer circuitry is further configured to receive the one or more constraints from a user via a user interface, in response to prompting the user via the user interface, the one or more constraints being operable to measure at least one of the altitude, velocity or acceleration in relation to the GPS receiver.

15. The GPS receiver of claim 13 , wherein the computer circuitry is further configured to:
calculate an estimated accuracy of the geographical location based on the number of GPS signals, a clock type associated with the GPS receiver, and the one or more constraints associated with the GPS receiver; and
provide the estimated accuracy of the geographical location to a user via the user interface.

16. The GPS receiver of claim 15 , wherein the computer circuitry is further configured to receive additional constraints from the user via the user interface in order to improve the estimated accuracy of the geographical location of the GPS receiver.

17. The GPS receiver of claim 13 , wherein the computer circuitry is further configured to:
calculate a second pseudo range of a second GPS sate

Assignees

• Raytheon Co

Inventors

• Robinson Ian S
• Hautzik Andrew M
• Crow Brandon

Classifications

• G01S19/426

  by combining or switching between position solutions or signals derived from different modes of operation in a single system · CPC title

• G01S19/50

  whereby the position solution is constrained to lie upon a particular curve or surface, e.g. for locomotives on railway tracks · CPC title

• G01S19/215

  issues related to spoofing · CPC title

• G01S19/42 Primary

  Determining position · CPC title

• G01S19/46

  the supplementary measurement being of a radio-wave signal type · CPC title