GPS Error Correction via Network of Fixed Point Ground Stations

Patent metadata

Field	Value
Publication number	US-2016274241-A1
Application number	US-201514661843-A
Country	US
Kind code	A1
Filing date	Mar 18, 2015
Priority date	Mar 18, 2015
Publication date	Sep 22, 2016
Grant date	—

Abstract

An error correcting location system includes a ground station with fixed reference coordinates. The ground station may receive satellite broadcast messages from a plurality of location system satellites. Further, the ground station may determine location coordinates based on the satellite broadcast messages, and compare the location coordinates to the fixed reference coordinates to determine a compensation value. In addition, the ground station may send the compensation value to location system devices. Upon receipt of the compensation value, the location system devices may utilize the compensation value to generate highly accurate location coordinates.

First claim

What is claimed is:

1 . A location system ground station comprising:
one or more processors; a first location system communication interface; one or more computer-readable media including a ground station identifier and first location coordinates, wherein the first location coordinates include fixed coordinates associated with the ground station; and processor-executable instructions maintained on the one or more computer-readable media which, when executed by the one or more processors, program the one or more processors to:
receive, via the first location system communication interface, satellite broadcast messages from a plurality of location system satellites;
determine second location coordinates associated with the ground station based at least in part on the satellite broadcast messages;
compare the first location coordinates of the ground station to the second location coordinates of the ground station;
determine a compensation value for a location system satellite of the plurality of location system satellites based at least in part on the comparison between the first location coordinates and the second location coordinates;
encrypt the compensation value with a ground station encryption key; and
send, via the first location system communication interface, the encrypted compensation value to a second location system communication interface of a location system device.

2 . The location system ground station of claim 1 , wherein determining the compensation value is based at least in part on determining a difference between the first location coordinates and the second location coordinates.

3 . The location system ground station of claim 1 , wherein the one or more processors are further programmed to:
determine a confidence value corresponding to the positional accuracy of the location system satellite based at least in part on the compensation value; send, via the first location system communication interface, the confidence value to the second location system communication interface of the location system device.

4 . The location system ground station of claim 1 , wherein the one or more processors are further programmed to:
compare the location compensation value to historical compensation data associated with the first plurality of location system satellites; determine the occurrence of a weather event based at least in part on comparison between the location compensation value and the historical compensation data; and send a notification of the weather event to the second location system communication interface of the location system device.

5 . An unmanned aerial vehicle (UAV) comprising:
one or more processors; a first location system communication interface; and one or more computer-readable media including processor-executable instructions maintained on the one or more computer-readable media which, when executed by the one or more processors, program the one or more processors to:
receive, via the first location system communication interface, satellite broadcast messages from a plurality of location system satellites, wherein individual satellite broadcast messages include satellite parameter information that indicates a location and identity of one of the location system satellites;
receive, via the first location system communication interface, first compensation values from a first ground station and second compensation values from a second ground station, wherein individual compensation values are associated with different pluralities of location system satellites; and
determine location coordinates associated with the UAV based at least in part on the satellite broadcast messages, and at least one of the first compensation values and the second compensation values.

6 . The UAV of claim 5 , wherein determining location coordinates associated with the UAV based at least in part on the satellite broadcast messages, and at least one of the first location compensation values and the second compensation values, further comprises:
selecting a compensation value from the first compensation values; determining location system coordinates based at least in part on satellite broadcast messages associated with a plurality of location system satellites mapped to the compensation value; and correcting the location system coordinates based at least in part on the compensation value.

7 . The UAV of claim 6 , wherein selecting the compensation value from the first compensation values is based at least in part on confidence values associated with the plurality of location system satellites.

8 . The UAV of claim 6 , wherein selecting the compensation value from the first compensation values is based at least in part on the first ground station being in closer proximity to the UAV than the second ground station.

9 . The UAV of claim 5 , wherein to determine location coordinates associated with the UAV based at least in part on the satellite broadcast messages and the location compensation values, further comprises:
selecting a first compensation value from the first compensations values; determining first location system coordinates based at least in part on satellite broadcast messages associated with a plurality of location system satellites mapped to the first compensation value; determining first corrected location system coordinates based at least in part on the first compensation value and the first location system coordinates; selecting a second compensation value from the second compensation values; determining second location system coordinates based at least in part on satellite broadcast messages associated with a plurality of location system satellites mapped to the second compensation value; determining second corrected location system coordinates based at least in part on the second compensation value and second location system coordinates; and averaging the first corrected location system coordinates and the second corrected location system coordinates.

10 . The UAV of claim 9 , further comprising weighting the averaged first corrected location system coordinates and the second corrected location system coordinates based in part on at least one of:
the proximity of the first ground station and the second ground station to the UAV; the age of the first compensation value and the second compensation value; confidence values associated with the first ground station and the second ground station, and confidence values associated with the plurality of location system satellites mapped to the first compensation value and the plurality of location system satellites mapped to the second compensation value.

11 . The UAV of claim 5 , further comprising determining confidence values representing the positional accuracy of the location system satellites based at least in part on the first compensation values and the second compensation values.

12 . The UAV of claim 5 , further comprising:
comparing the first location compensation values to historical compensation data associated with the first ground station; determine the occurrence of a weather event in a geographic area associated with the first ground station based at least in part on the comparison between the first location compensation values and the historical compensation data; and modifying a navigation path of the UAV based at least in part on the weather event.

13 . The UAV of claim 5 , further comprising validating the location coordinates based at least in part on Kalman filtering.

14 . The UAV of claim 5 , wherein the first location system communication interface includes a Global Pos

Assignees

• Amazon Tech Inc

Inventors

• Gentry Nicholas Kristofer

Classifications

• G01S19/074

  providing integrity data, e.g. WAAS · CPC title

• G01S19/072

  Ionosphere corrections · CPC title

• G01S19/41 Primary

  Differential correction, e.g. DGPS [differential GPS] · CPC title

• G01S19/03 Primary

  Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers · CPC title

• G01C21/00

  Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 (measuring distance traversed on the ground by a vehicle G01C22/00; control of position, course, altitude or attitude of vehicles G05D1/00; traffic control systems for road vehicles involving transmission of navigation instructions to the vehicle G08G1/0968) · CPC title