Method of detecting a target

• US 20060132354A1
• Filed: 01/29/2004
• Published: 06/22/2006
• Est. Priority Date: 01/30/2003
• Status: Active Grant

• Current Assignee: Qinetiq Limited (QinetiQ Group PLC)
• Original Assignee: Qinetiq Limited (QinetiQ Group PLC)
• Inventors: Lycett, Samantha Jane, Lane, Richard Oliver, Horey, Robert Michael, Beard, Gavin Spencer
• Granted Patent: US 8,094,060 B2
• Time in Patent Office: Days
• US Class Current: 342/160
• CPC Class Codes: G01S 13/5246 post processors for coherent MTI discriminators, e.g. residue cancellers, CFAR after Doppler filters
• CPC Class Codes: G01S 13/726 Multiple target tracking
• CPC Class Codes: G01S 7/2926 by integration

Abstract

A method for processing returns from a sensor, such as a radar system, in order to identify targets is provided. The method uses a track before detect routine to integrate data from several scans in order to give better discrimination. In running the track before detect routine however a number of possible target motions are postulated and the data combined accounting for such motions. A result above a threshold may then be indicative to a target present and moving with the postulated velocity. The method gives more accurate target detection as the combined data at the correct target motion postulate is more consistent than transient noise and clutter. Once a target has been identified it is preferably removed from the data set in searching for additional targets.

Claims

1. A method of detecting a target in data from a scene comprising the steps of;

i) taking a main data set comprising a series of scans of the scene, each scan comprising a plurality of data points corresponding to different parts of the scene,

ii) taking a first scan and calculating, for each data point in the first scan, an integrated data value at a predetermined number of postulated target velocities, each integrated data value being calculated using that data point in the first scan and data points in other scans that would correspond to a target moving at the postulated target velocity,

iii) identifying the greatest integrated data value and recalculating the remaining integrated data values excluding any data points which contributed to the greatest integrated data value,

iv) identifying for each data point in the first scan whether any of the integrated data values is above a threshold, and

v) using an integrated data value above the threshold as indication of a target.

2. A method according to claim 1 wherein the first scan is the latest scan acquired.

3. A method according to claim 1 wherein the main data set comprises data from between three and twenty scans.

4. A method according to claim 1 wherein the integrated data value is averaged before comparing to the threshold level.

5. A method as claimed in claim 1 wherein the step of identifying the greatest integrated data value, and recalculating the integrated data values is performed iteratively until no integrated value is above the threshold.

8. A method as claimed in claim 1 wherein the method further comprises the initial step of normalising the data points in the main data set.

9. A method as claimed in claim 1 wherein the method provides, for each target identified, an indication of the postulated velocity associated with that target.

10. A method as claimed in claim 1 wherein the main data set comprises data from a radar system.

11. A method as claimed in claim 10 wherein, prior to step (i) a within beam integration step is performed.

12. A computer programme for performing the method according to claim 1.

13. A computer programmed to perform the method according to claim 1.

14. A sensor with target detection comprising a detector arranged to receive signals from different parts of a scene, a data store arranged to store data from successive scans of the scene and a processor adapted to perform the method according to claim 1.

15. A sensor according to claim 14 wherein the sensor is a radar antenna.

16. A sensor according to claim 14 wherein the sensor also comprises a display for displaying any identified targets.

17. A sensor according to claim 14 wherein the sensor also comprises a tracker and the processor outputs an indication of the location and velocity of any targets to the tracker.

6. A method as claimed in 1 wherein the threshold level is calculated individually for each data point in the first scan.

7. A method as claimed in claim 6 wherein the threshold is based on an inverse gamma distribution applied to the main data set.