Method for localising at least one emitter

• US 20070069949A1
• Filed: 10/29/2004
• Published: 03/29/2007
• Est. Priority Date: 11/07/2003
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: Ferreol, Anne, Heurguier, Dominique
• Granted Patent: US 7,423,589 B2
• Time in Patent Office: Days
• US Class Current: 342/417
• CPC Class Codes: G01S 13/93 for anti-collision purposes
• 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 3/80 using ultrasonic, sonic or infrasonic waves
• 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

The invention relates to a method of localization of one or more sources, said source or sources being in motion relative to a network of sensors, the method comprising a step of separation of the sources in order to identify the direction vectors associated with the response of the sensors to a source having a given, incidence, characterized in that it comprises at least the following steps:

• • associating the direction vectors a_1m . . . a_Km obtained for the m^th transmitter and respectively at the instants t₁ . . . t_K,
  • localizing the mth transmitter from the associated vectors a_1m . . . a_Km.

Claims

1-9. -9. (canceled)

10. A method of localization of one or more sources, each source being in motion relative to a network of sensors, the method comprising the steps of separating the sources in order to identify the direction vectors associated with the response of the sensors to a source having a given incidence, associating direction vectors a_1m . . . a_Km obtained for the m^th transmitter and respectively at the instants t. . . t_k, localizing the m^th transmitter from the associated vectors a_1m . . . a_Km.

11. The method according to claim 10, wherein associating step comprises:

Step ASE-1;

Initialization of the process at k=2.

Step ASE-2;

For 1≦

m≦

M determining the indices i(m) in using the relationship

$d<br><br>\left(a_{k<br><br>\text{\hspace{1em}<br><br>}<br><br>m},b_{i<br><br>\left(m\right)}\right)=\underset{1\le <br><br>i\le <br><br>M}{\min }<br><br>\left[d<br><br>\left(a_{k<br><br>\text{\hspace{1em}<br><br>}<br><br>m},b_i\right)\right],$

 

the vector a_k,m and the vectors b_i identified at the instant t_k+1 for (1≦

i≦

M), setting up a function β

_m(t_k)=d(a_km, a_om),

Step ASE-3;

For 1≦

m≦

M performing the operation a_{k+1 m}=b_i(m),

Step ASE-4;

Incrementing k←

k+1 and if k<

K returning to the step ASE-1,

Step ASE-5;

Starting from the family of instants Φ

={t₁<

. . . <

t_k} thus obtained, extracting the instants t_i which do not belong to a zone defined by the curve β

_m(t_k) and a zone of tolerance.

12. The method according to claim 10, wherein the localizaing step comprises:

a normalized vector correlation L_k(x,y,z) maximizing in the space (x,y,z) of the position of a transmitter with

$L_K<br><br>\left(x,y,z\right)=\frac{{<br><br>b_K^H<br><br>v_K<br><br>\left(x,y,z\right)<br><br>}^2}{\left(b_K^H<br><br>b_K\right)<br><br>\left({v_K<br><br>\left(x,y,z\right)}^H<br><br>v_K<br><br>\left(x,y,z\right)\right)}$$\mathrm{with}$$b_K=\left[\begin{array}{c}{b}_{1<br><br>m}\\ \mathrm{⋮<br><br>}\\ b_{\mathrm{Km}}\end{array}\right]=v_K<br><br>\left(x_m,y_m,z_m\right)+w_K,<br><br>v_K<br><br>\left(x,y,z\right)=\left[\begin{array}{c}b<br><br>\left(t_1,x,y,z\right)\\ \mathrm{⋮<br><br>}\\ b<br><br>\left(t_K,x,y,z\right)\end{array}\right]<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{and}<br><br>\text{\hspace{1em}<br><br>}<br><br>w_K=\left[\begin{array}{c}{w}_{1<br><br>m}\\ \mathrm{⋮<br><br>}\\ w_{\mathrm{Km}}\end{array}\right]$

 

where w_K is the noise vector for all the positions (x, y, z) of a transmitter.

13. The method according to claim 12, wherein the vector b_k comprises a vector representing the noise, the components of which are functions of the components of the vectors a_1m . . . a_Km.

14. The method according to claim 12,wherein comprising:

a step in which the matrix of covariance R=E[w_Kw_K^H] of the noise vector is determined and in that the following criterion is maximized;

$L_K^{\mathrm{\prime <br><br>}}<br><br>\left(x,y,z\right)=\frac{{<br><br>b_K^H<br><br>R^{-1}<br><br>v_K<br><br>\left(x,y,z\right)<br><br>}^2}{\left(b_K^H<br><br>R^{-1}<br><br>b_K\right)<br><br>\left({v_K<br><br>\left(x,y,z\right)}^H<br><br>R^{-1}<br><br>v_K<br><br>\left(x,y,z\right)\right)}$

15. Method according to claim 14, wherein the evaluation of the criterion L_K(x,y,z) and/or of the criterion L_K′

(x,y,z) is recursive.

16. The method according to claim 14, wherein it comprises a step of comparison of the maximum values with a threshold value.

17. The method according to claim 11, wherein the value of K is initially fixed at K₀.

18. The method according to claim 10, wherein the transmitters to be localized are mobile and in that the vector considered is parameterized by the position of the transmitter to be localized and the speed vector.