Estimating the location of a wireless terminal based on radio-frequency pattern matching and cooperative measurements

• US 9,989,620 B1
• Filed: 10/18/2016
• Issued: 06/05/2018
• Est. Priority Date: 08/08/2014
• Status: Active Grant

• Current Assignee: Polaris Wireless Incorporated, Virginia Tech Intellectual Properties, Inc. (Virginia Polytechnic Institute and State University)
• Original Assignee: Polaris Wireless Incorporated
• Inventors: Gordon, Scot Douglas, Monir Vaghefi, Sayed Reza, Buehrer, R. Michael
• Primary Examiner(s): Afshar, Kamran
• Assistant Examiner(s): Kim, Minjung
• Application Number:
  US15/296,936
• Time in Patent Office: 595 Days
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04W 4/025 using location based information parameters
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 64/003 locating network equipment

Abstract

A method for estimating the location of a wireless terminal is disclosed that is based on using: the known location of one or more devices, empirical data that indicates the relative position of the wireless terminal to the devices, and empirical data that indicates the relative position of the wireless terminal (which is at an unknown location) relative to other wireless terminals that are also at unknown locations.

Claims

1. A method comprising:

receiving, at a data processing system, a measurement of a first location-dependent trait of a first radio signal that is transmitted between a first base station and a first wireless terminal;

receiving, at the data processing system, a measurement of a second location-dependent trait of a second radio signal that is transmitted between the first wireless terminal and a second wireless terminal that are at unknown locations;

generating a first candidate estimate of a location of the first wireless terminal based on the measurement of the first location-dependent trait of the first radio signal, wherein the generating of the first candidate estimate of the location of the first wireless terminal comprises pattern matching the measurement of the first location-dependent trait of the first radio signal to a database that associates (1) locations and (2) predicted values of the first location-dependent trait of the first radio signal at each of those locations;

generating a second candidate estimate of the location of the first wireless terminal based on the measurement of the first location-dependent trait of the first radio signal; and

generating an improved estimate of the location of the first wireless terminal based on;

(i) the first candidate estimate of the location of the first wireless terminal,

(ii) the second candidate estimate of the location of the first wireless terminal, and

(iii) the measurement of the second location-dependent trait of the second radio signal.

2. The method of claim 1 wherein the first radio signal is transmitted from the first base station to the first wireless terminal.

3. The method of claim 1 wherein the first radio signal is transmitted from the first wireless terminal to the first base station.

4. The method of claim 1 wherein the first location-dependent trait is timing advance.

5. The method of claim 1 wherein the first location-dependent trait is reference signal received power.

6. The method of claim 1 wherein the second location-dependent trait is indicative of distance between the first wireless terminal and the second wireless terminal.

7. The method of claim 1 wherein the improved estimate of the location of the first wireless terminal is selected to be either:

(i) the first candidate estimate of the location of the first wireless terminal, or

(ii) the second candidate estimate of the location of the first wireless terminal,

based on the measurement of the second location-dependent trait of the second radio signal.

8. The method of claim 1 wherein the generating of the first candidate estimate and the generating of the second candidate estimate are both based on using the same location estimation technique that uses the measurement of the first location-dependent trait of the first radio signal.

9. A method comprising:

receiving, at a data processing system, a measurement of a first location-dependent trait of a first radio signal that is transmitted between a first base station and a first wireless terminal;

receiving, at the data processing system, an indication of distance between the first wireless terminal and a second wireless terminal that are at unknown locations;

generating a first candidate estimate of a location of the first wireless terminal based on the measurement of the first location-dependent trait of the first radio signal, wherein the generating of the first candidate estimate of the location of the first wireless terminal comprises pattern matching the measurement of the first location-dependent trait of the first radio signal to a database that associates (1) locations and (2) predicted values of the first location-dependent trait of the first radio signal at each of those locations;

generating a second candidate estimate of the location of the first wireless terminal based on the measurement of the first location-dependent trait of the first radio signal; and

generating an improved estimate of the location of the first wireless terminal by selecting the improved estimate of the location of the first wireless terminal to be either;

(i) the first candidate estimate of the location of the first wireless terminal, or

(ii) the second candidate estimate of the location of the first wireless terminal,

wherein the selecting is based on the indication of distance between the first wireless terminal and the second wireless terminal.

10. The method of claim 9 wherein the generating of the first candidate estimate and the generating of the second candidate estimate are both based on using the same location estimation technique that uses the measurement of the first location-dependent trait of the first radio signal.

11. A method comprising:

receiving, at a data processing system, a measurement of a first location-dependent trait of a first radio signal that is transmitted between a first base station and a first wireless terminal;

receiving, at the data processing system, a position of the first wireless terminal relative to a second wireless terminal that are at unknown locations;

generating a first candidate estimate of a location of the first wireless terminal based on the measurement of the first location-dependent trait of the first radio signal, wherein the generating of the first candidate estimate of the location of the first wireless terminal comprises pattern matching the measurement of the first location-dependent trait of the first radio signal to a database that associates (1) locations and (2) predicted values of the first location-dependent trait of the first radio signal at each of those locations;

generating a second candidate estimate of the location of the first wireless terminal based on the measurement of the first location-dependent trait of the first radio signal; and

generating an improved estimate of the location of the first wireless terminal based on;

(i) the first candidate estimate of the location of the first wireless terminal,

(ii) the second candidate estimate of the location of the first wireless terminal, and

(iii) the position of the first wireless terminal relative to the second wireless terminal.

12. The method of claim 11 wherein the generating of the first candidate estimate and the generating of the second candidate estimate are both based on using the same location estimation technique that uses the measurement of the first location-dependent trait of the first radio signal.

13. A method comprising:

receiving, at a data processing system, a measurement of a first location-dependent trait of a first radio signal that is transmitted between a first base station and a first wireless terminal;

receiving, at the data processing system, an indication of distance between the first wireless terminal and a second wireless terminal that are at unknown locations;

generating a first candidate estimate of a location of the first wireless terminal based on the measurement of the first location-dependent trait of the first radio signal;

generating a second candidate estimate of the location of the first wireless terminal based on the measurement of the first location-dependent trait of the first radio signal, wherein the generating of the first candidate estimate and the generating of the second candidate estimate (a) are both based on using the same location estimation technique that uses the measurement of the first location-dependent trait of the first radio signal, and (b) comprise pattern matching the measurement of the first location-dependent trait of the first radio signal to a database that associates (1) locations and (2) predicted values of the first location-dependent trait of the first radio signal at each of those locations; and

generating an improved estimate of the location of the first wireless terminal based on;

(i) the first candidate estimate of the location of the first wireless terminal,

(ii) the second candidate estimate of the location of the first wireless terminal, and

(iii) the indication of distance between the first wireless terminal and the second wireless terminal.