Method and System for Target Positioning and Tracking in Cooperative Relay Networks

• US 20100177681A1
• Filed: 01/09/2009
• Published: 07/15/2010
• Est. Priority Date: 01/09/2009
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation), Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Lighting & Technology Corporation (Toshiba Corporation)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Sahinoglu, Zafer
• Granted Patent: US 8,259,699 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/46 Indirect determination of position data
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 2013/466 by Trilateration, i.e. two antennas or two sensors determine separately the distance to a target, whereby with the knowledge of the baseline length, i.e. the distance between the antennas or sensors, the position data of the target is determined
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial

Abstract

A method and system locates a position of a transceiver in a cooperative relay network of nodes. A primary node broadcasts a range request (RREQ) message. A target node, in response to receiving the RREQ message, broadcasts a range reply (RREP) message, wherein the RREP message includes a time difference between receiving the RREQ message and broadcasting the RREP message. A secondary node, in response to receiving the RREQ message and the RREP message, broadcasts a range data (RDAT) message, wherein the RDAT message includes a time difference between receiving the RREQ message and the RREP message. Then, a position solver can determine a location of the target node based on the time differences in the RREP message and the RDAT message.

Claims

1. A method for locating a position of a transceiver, in a cooperative relay network of nodes, comprising:

broadcasting, by a primary node in a cooperative relay network, a range request (RREQ) message;

broadcasting, by a target node in the cooperative relay network in response to receiving the RREQ message, a range reply (RREP) message, wherein the RREP message includes a time difference between receiving the RREQ message and broadcasting the RREP message;

broadcasting, by a secondary node in the cooperative relay network in response to receiving the RREQ message and the RREP message, a range data (RDAT) message, wherein the RDAT message includes a time difference between receiving the RREQ message and the RREP message; and

determining, in a position solver of the cooperative relay network, a location of the target node based on the time differences in the RREP message and the RDAT message.

2. The method of claim 1, further comprising:

implementing the position solver in the target node.

3. The method of claim 1, further comprising:

implementing the position solver in a coordinator node in the cooperative relay network.

4. The method of claim 1, wherein the target node is mobile.

5. The method of claim 1, wherein each message includes a messageType field identifying the message as the RREQ, RREP or RDAT message, a localID field for storing a network address of the primary reference node, a sourceID field for identifying the primary reference node, a targetID for identifying the target node, a sequenceNo field for counting a number of position update requests, and a timedifference field for storing the time difference.

6. The method of claim 1, wherein a range estimate z between the primary node and the secondary node is based on a round trip time for the RREQ message and RREP.

7. The method of claim 6, wherein the range estimate is

8. The method of claim 1, wherein the network has multi-path channels, and further comprising:

searching for a first copy of the RREQ message at the target node and a first copy of the RREP message at the primary node.

9. The method of claim 1, wherein a statistical approach uses a maximum likelihood estimator, which estimates the target coordinates that maximize

p_θ

(z)=∫

p_θ

(z|n_T)ƒ

_θ

(n_T)dn_T,

where ƒ

_θ

(n_T) is the probability density function of noise components due to the measurements at the target node.

10. The method of claim 1, further comprising:

broadcasting a plurality of RREQ, RREP and RDAT messages over time to track the target node.

11. A system for locating a position of a transceiver, in a cooperative relay network of nodes, comprising:

a primary node in a cooperative relay network is configured to broadcast a primary node, a range request (RREQ) message;

a target node in the cooperative relay network is configured to broadcast, in response to receiving the RREQ message, a range reply (RREP) message, wherein the RREP message includes a time difference between receiving the RREQ message and broadcasting the RREP message;

a secondary node in the cooperative relay network is configured to broadcast, in response to receiving the RREQ message and the RREP message, a range data (RDAT) message, wherein the RDAT message includes a time difference between receiving the RREQ message and the RREP message; and

a position solver of the cooperative relay network determines a location of the target node based on the time differences in the RREP message and the RDAT message.