High speed angle-to-target estimation for a multiple antenna system and method

• US 8,933,836 B1
• Filed: 09/30/2011
• Issued: 01/13/2015
• Est. Priority Date: 09/30/2011
• Status: Active Grant

• Current Assignee: Rockwell Collins, Inc. (Rtx Corporation)
• Original Assignee: Rockwell Collins, Inc. (Rtx Corporation)
• Inventors: Woodell, Daniel L., Finley, Jeffery A., Van Dusseldorp, David L.
• Primary Examiner(s): Sotomayor, John B
• Assistant Examiner(s): WINDRICH, MARCUS E
• Application Number:
  US13/251,063
• Time in Patent Office: 1,201 Days
• Field of Search: 342/29, 342/79, 342/80, 342/139, 342149-154
• US Class Current: 342/149
• CPC Class Codes: G01S 13/44 Monopulse radar, i.e. simultaneous lobing
• CPC Class Codes: G01S 13/72 for two-dimensional tracking, e.g. combination of angle and range tracking, track-while-scan radar
• CPC Class Codes: G01S 13/933 of aircraft or spacecraft
• CPC Class Codes: G01S 7/4026 Antenna boresight

Abstract

A multiple beam receiving system provides an angle estimate to targets. The system tracks movements of the targets over time and generates calibration information. The system uses the calibration information to more accurately estimate angle-to-target. The multiple beam receiving system can be part of a monopulse or other radar system, a traffic collision avoidance system, or other electromagnetic sensor.

Claims

1. A multiple antenna lobe receiving system, comprising:

a processor; and

a memory coupled to the processor and containing program instructions that, when executed by the processor, cause the multiple antenna lobe receiving system to

receive multiple antenna lobe return data from two or more receive channels; and

track movement of targets using the multiple antenna lobe return data over time;

wherein the movement is used to provide system calibration data to correct mismatch errors associated with the multiple antenna lobe return data, and wherein an angle-to-target estimate for each target of the targets is provided without servoing an antenna to point to each target and wherein target movement as sensed by the multiple antenna lobe receiving system is compared to a linearized target movement model for each target of the targets to estimate the system calibration data.

2. The multiple antenna lobe receiving system of claim 1, wherein the multiple antenna lobe receiving system is a radar system.

3. The multiple antenna lobe receiving system of claim 1, wherein the multiple antenna lobe receiving system is a traffic collision avoidance system.

4. The multiple antenna lobe receiving system of claim 1, wherein the system calibration data is at least one of gain, phase, gain slope, phase slope, or a function driven by sensed angle and producing an angular error offset.

5. The multiple antenna lobe receiving system of claim 4, wherein the linearized target movement model is taken from a Kalman filter using an estimate of errors of the multiple antenna lobe receiving system.

6. The multiple antenna lobe receiving system of claim 5, wherein the comparison is performed iteratively producing new estimates of target position and system error terms.

7. The multiple antenna lobe receiving system of claim 1, wherein the multiple antenna lobe receiving system is a monopulse system without a microwave monopulse comparator.

8. The multiple antenna lobe receiving system of claim 1, wherein the system calibration data is generated from calibration averaged from multiple detections of multiple targets.

9. A method of providing angle-to-target estimates for targets using an avionics receiver, the method comprising:

receiving multiple antenna lobe responses on respective channels;

tracking movement of the targets using signals derived from the multiple antenna lobe responses over time;

providing error data using the movement of the targets and expected movement of the targets wherein the error data is related to mismatch errors, wherein the movement of the targets is used to provide calibration data, wherein the movement of the targets as derived from the multiple antenna lobe responses is compared to a linearized target movement for each target of the targets to provide the calibration data; and

determining an angle-to-target from the multiple antenna lobes responses.

10. The method of claim 9, wherein the error data represents a phase mismatch associated with the channels.

11. The method of claim 9, wherein the error data represents an amplitude mismatch from sum and difference channels generated from the multiple antenna lobe signals.

12. The method of claim 11, wherein the multiple antenna lobe returns are TCAS pulses.

13. The method of claim 9, wherein the movement uses a maximum return associated with the multiple antenna lobe signals on the channels.

14. The method of claim 9, wherein the error data is determined using least square fit in a Kalman filter.

15. A receiver system, comprising:

means for analyzing multiple antenna lobe derived return data to identify targets; and

means for determining a mismatch error associated with each antenna lobe'"'"'s response associated with the multiple antenna lobe derived return data wherein an angle-to-target estimate for each target is provided using the mismatch error and the multiple antenna lobe return data, and wherein target movement as sensed by the receiver system is compared to a linearized target movement model for each target to estimate system calibration data.

16. The system of claim 15, wherein the receiver system is a phase monopulse system.

17. The system of claim 15, wherein the receiver system is an amplitude comparison monopulse system.

18. The system of claim 15, wherein the multiple antenna lobe derived return data are received from sum and difference receive channels,

wherein the sum and difference receive channels do not include microwave monopulse comparator.

19. The system of claim 15, further compromising:

means for sensing temperature, and

means for storing the temperature with respect to the mismatch error.

20. The system of claim 15, wherein the receiver system is part of a TCAS.

21. The system of claim 15, wherein means for determining includes a Kalman filter.