Method and system for localizing a target in an interrogation-response system

• US 20030222810A1
• Filed: 04/03/2003
• Published: 12/04/2003
• Est. Priority Date: 04/05/2002
• Status: Active Grant

• Current Assignee: Thales SA
• Original Assignee: Thales SA
• Inventors: Roze, Thierry, Trin, Jean-Marc
• Granted Patent: US 6,933,879 B2
• Time in Patent Office: Days
• US Class Current: 342/45
• CPC Class Codes: G01S 13/78 discriminating between different kinds of targets, e.g. IFF-radar, i.e. identification of friend or foe G01S13/75, G01S13/79 take precedence
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial

Abstract

In a method and system to determine the position of a target by means of an IFF type antenna, the antenna having a given direction of aim, the method comprises a step for combining the distance D from the target to the carrier, the altitude A of the target, the altitude A_pf of the carrier equipped with the IFF antenna and the angular error value of the target and the direction of aim of the antenna beam to localize the target with precision. Application to IFF interrogations in mode C

Claims

1. - A method to determine the position of one or more targets by means of an IFF type antenna, the antenna having a given direction of aim, wherein the method comprises at least one step for combining at least three parameters that represent the position of the target or targets, the position of the carrier and the antenna beam-aiming direction to localize the target.

2. - A method according to claim 1 wherein the three parameters used are, for example, the distance D from the target to the carrier, the altitude A of the target and the altitude A_pf of the carrier equipped with the IFF antenna and the angular error value of the target.

3. - A method according to one of the claims 1 and 2, comprising the following steps:

Determining the circle C₁ resulting from the intersection between the iso-distance sphere on which the target may be situated and a plane substantially parallel to the vertical plane of the carrier equipped with the IFF antenna.

Determining the circle C₂ that comes from the intersection between the iso-altitude plane of the target and the iso-distance sphere,

Achieving the intersection of the two circles C₁ and C₂ to obtain the coordinates of the target.

4. - A method according to claim 3, wherein the coordinates of the target are given by the following relationships:

6. - A method according to one of the claims 1 to 5 wherein the mode of interrogation from the carrier to the target is an IFF mode C.

7. - A system for the localization of one or more targets by a carrier by means of a carrier equipped with an antenna having a given direction of aim or secondary radar wherein the system comprises at least one primary radar and an IFF system linked with the secondary radar and being adapted to the implementing of at least one of the characteristics of the method according to the claims 1 to 6.

5. - A method according to claim 5 comprising a step in which the x coordinates are specified as follows: