Method and System for Using Indirect Paths of Ultra Wideband Signals to Localize a Wireless Communication Node on a Body.

• US 20130222185A1
• Filed: 08/23/2011
• Published: 08/29/2013
• Est. Priority Date: 09/16/2010
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Ouvry, Laurent, Ben Hamida, Elyes, Denis, Benot
• Granted Patent: US 9,389,303 B2
• Time in Patent Office: Days
• US Class Current: 342/387
• CPC Class Codes: G01S 5/0218 Multipath in signal reception
• CPC Class Codes: G01S 5/0273 using multipath or indirect path propagation signals in position determination
• CPC Class Codes: G01S 5/0289 of multiple transceivers, e.g. in ad hoc networks
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

A method and a system are provided which are able to utilize indirect paths of signals of UWB type to locate a wireless communication node possessed by a body. The present method and system can notably apply to cooperative body networks implementing several wireless nodes able to communicate with one another.

Claims

1. A method for locating a first wireless communication node possessed by a mobile body, said first node being within transmission range of at least one second node also possessed by said mobile body, said nodes being able to transmit and/or receive radiofrequency signals, said method comprising:

performing at least one measurement of time of flight of an indirect path of ultra wideband signal transmitted between the first node and the second node, said path arising from a single reflection on a surface external to said body, between the first node and the second node;

utilizing said time of flight measurement to locate the first node at least with respect to the second node.

2. The locating method as claimed in claim 1, in which the time of flight measurement is performed by estimating the impulse response of the transmission channel between the first node and the second node and by extracting from said impulse response at least one time of flight corresponding to a path having undergone a reflection between its transmission and its reception.

3. The locating method as claimed in claim 1, in which the indirect path arises from a reflection on the ground.

4. The locating method as claimed in claim 1, in which:

either said signal is transmitted by the first node and received by the second node;

or said signal is transmitted by the second node and received by the first node.

7. The locating method as claimed in claim 1, in which the step of locating the first node at least with respect to the second node is performed by jointly utilizing said measurement of time of flight of the indirect path between the first node and the second node, and at least one measurement of direct path between the first node and another node possessed by the mobile body.

5. A method for locating a first wireless communication node possessed by a mobile body, said first node being within transmission range of at least one second node also possessed by said mobile body, said nodes being able to transmit and/or receive radiofrequency signals, said method comprising the following steps:

performing at least one measurement of time of flight of an indirect path of ultra wideband signal transmitted between the first node and the second node, said path arising from a single reflection on a surface external to said body, between the first node and the second node;

utilizing said time of flight measurement to locate the first node at least with respect to the second node,

wherein the first node and the second node are attached to one and the same articulated body provided with known bio-mechanical constraints, the position of the second node on said organic body being known, the method comprising a step of joint utilization of said known position of the second node, of said bio-mechanical constraints, and of the measured time of flight of said indirect path to determine the location of the first node.

6. The locating method as claimed in claim 5, in which the step of locating the first node at least with respect to the second node is performed by jointly utilizing said measurement of time of flight of the indirect path between the first node and the second node, and at least one measurement of direct path between the first node and another node possessed by the mobile body.