Position And Motion Informed Navigation System

Patent metadata

Field	Value
Publication number	US-2016266259-A1
Application number	US-201414453537-A
Country	US
Kind code	A1
Filing date	Aug 6, 2014
Priority date	Aug 6, 2014
Publication date	Sep 15, 2016
Grant date	—

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 one or more GPS satellites; receive one or more constraints that describe at least one characteristic of the GPS receiver's motion or position when the number of GPS signals are below a defined value, wherein the one or more constraints enable a determination of a geographical location associated with the GPS receiver using the number of GPS signals from the one or more GPS satellites; calculate a plurality of pseudo ranges between the GPS receiver and the one or more GPS satellites at various orbital positions of the GPS satellites over a period of time; and determine the geographical location of the GPS receiver using the plurality of pseudo ranges and known correlations with respect to previous geographical locations associated with the GPS receiver.

2 . The computer circuitry of claim 1 , wherein the known correlations include known mathematical relationships between the previous geographical locations of the GPS receiver and a current geographical location of the GPS receiver.

3 . The computer circuitry of claim 1 , further configured to receive the one or more constraints when the defined value is four GPS signals.

4 . The computer circuitry of claim 1 , further configured to receive the one or more constraints from at least one of a user and a sensor that measures at least one of the altitude, velocity or acceleration in relation to the GPS receiver.

5 . The computer circuitry of claim 1 , wherein the one or more constraints include at least one of a position, a velocity, or an acceleration associated with the GPS receiver.

6 . The computer circuitry of claim 1 , further configured to:
determine that a number of GPS signals being received from the one or more GPS satellites are above the defined value; organize the GPS signals into at least two distinct GPS signal groupings, wherein the distinct GPS signal groups have a descending number of GPS signals; and compare potential geographical positions of the GPS receiver determined using the distinct GPS signal groupings in order to identify a spoofed GPS signal from the number of GPS signals.

7 . The computer circuitry of claim 1 , 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.

8 . A method for determining a geographical location, the method comprising:
determining that a number of global positioning system (GPS) satellites within a line of sight to a GPS receiver is below a defined value; receiving one or more constraints that describe at least one characteristic of the GPS receiver's position or motion; calculating a plurality of pseudo ranges between the GPS receiver and the number of GPS satellites, wherein the plurality of pseudo ranges are to various orbital positions of the GPS satellites over a period of time; and determining the geographical location of the GPS receiver and a motion associated with the GPS receiver using the plurality of pseudo ranges and the one or more constraints that describe the motion or position of the GPS receiver.

9 . The method of claim 8 , further comprising determining the geographical location and the motion associated with the GPS receiver using the constraints and at least one of previously estimated positions, accelerations, or velocities associated with the GPS receiver.

10 . The method of claim 8 , wherein the motion associated with the GPS receiver includes an acceleration or velocity of the GPS receiver.

11 . The method of claim 8 , wherein receiving the one or more constraints includes receiving at least one of: a position associated with the GPS receiver in X, Y, or Z dimensions, a velocity associated with the GPS receiver in X, Y, or Z dimensions, and an acceleration associated with the GPS receiver in X, Y, or Z dimensions.

12 . The method of claim 8 , further comprising receiving the one or more constraints from a user in response to informing the user that the number of GPS satellites in the line of sight to the GPS receiver is insufficient for determining the geographical location.

13 . The method of claim 8 , further comprising receiving the one or more constraints by a sensor that measures at least one of an altitude, velocity or acceleration associated with the GPS receiver.

14 . The method of claim 8 , further comprising utilizing a Kalman filter for determining the geographical location and motion of the GPS receiver, wherein the Kalman filter generates the geographical location and motion of the GPS receiver using the constraints and associated mathematical relationships of motion over time.

15 . The method of claim 8 , further comprising:
calculating an estimated accuracy of the geographical location based on a number of GPS signals received from the GPS satellites, a clock type associated with the GPS receiver, and the one or more constraints; and providing the estimated accuracy of the geographical location to a user.

16 . The method of claim 15 , further comprising receiving additional constraints from the user in order to improve the estimated accuracy of the geographical location.

17 . A system for determining a geographical location, the system comprising:
a constraint module configured to receive one or more constraints that describe at least one characteristic of a global position system (GPS) receiver when a number of GPS satellites within a line of sight to the GPS receiver is below a defined value; 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 the constraints with respect to previous geographical locations estimated by the GPS receiver.

18 . The system of claim 18 , further comprising a geographical location accuracy module configured to calculate an estimated accuracy of the geographical location based on a number of GPS signals, a clock type associated with the GPS receiver, and the one or more constraints.

19 . The system of claim 18 , further comprising a spoofed signal detection module configured to:
determine that a number of GPS signals being received from the GPS satellites are above the defined value; organize the GPS signals into at least two distinct GPS signal groupings, wherein the distinct GPS signal groups have a descending number of GPS signals; and compare potential geographical positions of the GPS receiver determined using the distinct GPS signal groupings in order to identify a spoofed GPS signal from the GPS signals.

20 . The system of claim 18 , wherein the constraint module is further configured to receive the one or more constraints, including a position associated with the GPS receiver in X, Y, or Z dimensions, a velocity associated with the GPS receiver in X, Y, or Z dimensions, and an acceleration associated with the GPS receiver in X, Y, or Z dimensions.

21 . The system of claim 18 , wherein the constraint module is further configure

Assignees

• Raytheon Co

Inventors

• Robinson Ian S
• Hautzik Andrew M
• Crow Brandon

Classifications

• G01S19/215

  issues related to spoofing · 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

• G01S19/42 Primary

  Determining position · CPC title

• G01S19/426

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

• G01S19/46

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