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

• US 9,596,571 B1
• Filed: 12/16/2014
• Issued: 03/14/2017
• 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, Virginia Polytechnic Institute and State University
• Inventors: Monir Vaghefi, Sayed Reza, Buehrer, R. Michael, Gordon, Scot Douglas
• Primary Examiner(s): Siddiqui, Kashif
• Assistant Examiner(s): Kim, Minjung
• Application Number:
  US14/572,070
• Time in Patent Office: 819 Days
• US Class Current: 1/1
• 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 wireless terminal and a first base station;

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

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

generating;

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

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

based on pattern matching of the measurement of the first location-dependent trait of the first radio signal;

generating;

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

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

based on pattern matching of the measurement of the second location-dependent trait of the second radio signal; and

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

(i) a measure of error between the first candidate estimate of the location of the first wireless terminal and the first candidate estimate of the location of the second wireless terminal as compared to the third location-dependent trait of the third radio signal,

(ii) a measure of error between the first candidate estimate of the location of the first wireless terminal and the second candidate estimate of the location of the second wireless terminal as compared to the third location-dependent trait of the third radio signal, and

(iii) a measure of error between the second candidate estimate of the location of the first wireless terminal and the first candidate estimate of the location of the second wireless terminal as compared to the third location-dependent trait of the third 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 third location-dependent trait is round-trip time.