Method for passively locating a non-movable transmitter

• US 10,156,630 B2
• Filed: 11/10/2015
• Issued: 12/18/2018
• Est. Priority Date: 11/28/2014
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: Enderli, Cyrille, Grandin, Jean-Francois, Seute, Hugo
• Primary Examiner(s): Alam, Fayyaz
• Application Number:
  US15/526,751
• Publication Number:
  US 20170336492A1
• Time in Patent Office: 1,134 Days
• Field of Search: 455 132, 455 121, 455 7, 455 301- 306
• CPC Class Codes: G01S 1/245 Details of receivers cooperating therewith, e.g. determining positive zero crossing of third cycle in LORAN-C
• CPC Class Codes: G01S 5/0278 involving statistical or probabilistic considerations G01S5/0252, G01S5/0294 take precedence
• 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

Abstract

A method for passively locating a non-movable transmitter on the ground implemented by a group of at least one receiving station, each of the receiving stations comprising a detector of radars and a time reference, the set of time references being mutually synchronized, the transmitter transmitting a set of periodic pulses, wherein a first estimation of the position of the transmitter is carried out by the Bancroft scheme on the basis of the mean arrival times of the pulses transmitted by the transmitter at the level of each station of the group of at least one receiving station, the result obtained being used thereafter as point for initializing a maximum likelihood scheme so as to converge toward the position of the transmitter.

Claims

1. A method for passively locating a non-movable transmitter on the ground implemented by a group of at least two receiving stations, each of the receiving stations comprising a detector of radars and a time reference, the set of time references being mutually synchronized, said transmitter transmitting a set of periodic pulses, the duration of a pulse train being sufficiently short for each of the receiving stations to always have a trajectory that can be regarded as a uniform rectilinear motion, each receiving station being configured to measure arrival times of the pulses of the transmitter and to compute a mean arrival time of said pulses,

said method wherein a first estimation of the position of said transmitter is carried out by the Bancroft scheme on the basis of the mean arrival times of the pulses transmitted by the transmitter at the level of each station of the group of at least two receiving stations, the estimation obtained being used thereafter as point for initializing a maximum likelihood scheme so as to converge toward the position of said transmitter.

2. The method as claimed in claim 1, implemented by at least two receiving stations in which said method comprises:

A step Etp1 of measuring the arrival times of the pulses of the transmitter by each receiving station,

A step Etp2 of computing the mean arrival time of the pulses by each receiving station,

A step Etp3 of dispatching the computed mean arrival times of the pulses to a predetermined receiving station,

A step Etp4 of computing, by said predetermined receiving station, the location of the transmitter on the basis of all the mean arrival times of the pulses with the aid of the Bancroft scheme and then of the maximum likelihood scheme.

3. The method as claimed in claim 1, wherein the receiving station or stations are airborne receiving stations.

4. The method as claimed in claim 1, wherein the receiving station or stations are space receiving stations.