Method for tracking a transmitter by means of a synthetic sparse antenna network

• US 7,907,089 B2
• Filed: 04/25/2005
• Issued: 03/15/2011
• Est. Priority Date: 05/14/2004
• Status: Expired due to Fees

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: Ferreol, Anne, Heurguier, Dominique
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Nguyen; Nga X
• Application Number:
  US11/569,059
• Publication Number:
  US 20070216577A1
• Time in Patent Office: 2,150 Days
• Field of Search: 342351-477
• US Class Current: 342/465
• CPC Class Codes: G01S 2205/03 Airborne
• CPC Class Codes: G01S 3/46 using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
• CPC Class Codes: G01S 3/74 Multi-channel systems specially adapted for direction-finding, i.e. having a single antenna system capable of giving simultaneous indications of the directions of different signals systems in which the directions of different signals are determined sequentially and displayed simultaneously G01S3/04, G01S3/14
• CPC Class Codes: G01S 3/8006 Multi-channel systems specially adapted for direction-finding, i.e. having a single aerial system capable of giving simultaneous indications of the directions of different signals
• CPC Class Codes: G01S 5/0249 Determining position using measurements made by a non-stationary device other than the device whose position is being determined

Abstract

Method of locating one or more transmitters on the basis of an array of sensors moving with respect to the transmitters comprising at least the following steps:

• • determining the direction vectors â_k corresponding to the response of the array of sensors to a source with incidence (θ, Δ) as a function of the incidence parameters θ, Δ, and of the parameter ρ related to the distortion of the phases on the sensors,
  • transforming this vector â_k so as to eliminate the unknown parameter ρ, into a vector ĉ_km, ĉ′_km,
  • using the transformed vector to obtain the position of the transmitter using a maximized locating criterion.

Claims

1. A method of locating one or more transmitters on the basis of an array of sensors moving with respect to the transmitters, comprising at least the following steps for an m-th transmitter of the transmitters:

determining a direction vector â

_km corresponding to the response of the array of sensors to a source with incidence (θ

, Δ

) as a function of the incidence parameters θ

, Δ

, and of an unknown parameter ρ

related to the distortion of the phases on the sensors,

transforming the direction vector so as to eliminate the unknown parameter ρ

, into a transformed direction vector,

using the transformed direction vector to obtain the position of the transmitter using a maximized locating criterion;

wherein the transformation step comprises at least the following steps;

choosing a reference instant i, and

constructing the transformed direction vector ĉ

′

_km whose components correspond to the ratio of the components between the given instant k and the instant i

2. The method as claimed in claim 1, wherein the locating criterion is equal to:

3. The method as claimed in claim 1, further comprising the following iterative steps:

identifying vectors c′

_(K+1)m at an instant t_K+1;

calculating a criterion L_K+1(x,y,z) in an iterative manner and minimizing the criterion L_K+1(x,y,z) to obtain a new position estimation (x_m,y_m,z_m) for the transmitter.

4. The method as claimed in claim 1, wherein a phase tracking is performed for the vectors ĉ

′

_km.

5. The method as claimed in claim 1, further comprising a step of filtering the direction vectors â

_k.

6. The method as claimed in claim 1 wherein a sliding time window is used by taking i=k−

1 or i=k−

L.

7. The method as claimed in claim 2, further comprising the following iterative steps:

identifying vectors c′

_(K+1)m at an instant t_K+1;

calculating a criterion L_K+1(x,y,z) in an iterative manner and minimizing the criterion L_K+1(x,y,z) to obtain a new position estimation (x_m,y_m,z_m) for the transmitter.

8. A method of locating one of more transmitters on the basis of an array of sensors moving with respect to the transmitters which comprises at least the following steps:

receiving signals from at least one of the transmitters by the sensors and determining a direction vector â

_km;

choosing a reference channel or sensor and constructing a vector b(t_K,x_m,z_m,ρ

) whose components correspond to the ratio of 2 channels according to the received signals, where m denotes the m-th transmitter of the transmitters;

9. A method of locating one of more transmitters on the basis of an array of sensors moving with respect to the transmitters, comprising at least the following steps for an m-th transmitter of the transmitters:

receiving signals from at least on of the transmitters by the sensors;

using the received signals to construct a direction vector;

â

_km(ρ

)=a(θ

_k, Δ

_k, ρ

)+e_km

constructing a vector {circumflex over (b)}_km of dimension (N−

1)*1

10. The method as claimed in claim 9, wherein the locating criterion comprises a normalized vector correlation criterion L_k(x, y, z) in the position space (x, y, z) of a transmitter with:

11. The method as claimed in claim 10, further comprising the following iterative steps:

identifying the vectors c_(K+1)m at an instant t_k+1;

calculating a criterion L_K+1(x,y,z) in an iterative manner and minimizing the criterion L_K+1(x,y,z) to obtain a new position estimation (x_m,y_m,z_m) for the transmitter.

12. The method as claimed in claim 10, further comprising the following iterative steps:

identifying the vectors c_(K+1)m at an instant t_k+1;

calculating a criterion L_K+1(x,y,z) in an iterative manner and minimizing the criterion L_K+1(x,y,z) to obtain a new position estimation (x_m,y_m,z_m) for the transmitter.