DETERMINING AT LEAST ONE COORDINATE OF AN OBJECT USING INTERSECTING SURFACES

• US 20110227783A1
• Filed: 03/31/2010
• Published: 09/22/2011
• Est. Priority Date: 01/31/2008
• Status: Active Grant

• Current Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Original Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Inventors: Yannone, Ronald M.
• Granted Patent: US 8,436,762 B2
• Time in Patent Office: Days
• US Class Current: 342/156
• CPC Class Codes: G01S 11/02 using radio waves G01S19/00 takes precedence
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 7/295 Means for transforming co-ordinates or for evaluating data, e.g. using computers

Abstract

In an embodiment, a coordinate determiner is operable to identify at least first and second surfaces that each approximately intersect an object, and to determine at least two approximate coordinates of the object from the first and second surfaces, where at least one of the surfaces is nonplanar. For example, if the coordinate determiner is disposed on a fighter jet having at least to short-baseline-interferometers (SBIs), then two surfaces may be the surfaces of two cones having two of the SBIs as respective vertices, the object may be a close-in target, and the coordinate determiner may determine the azimuth and elevation of the target from the cone surfaces. Furthermore, the coordinate determiner or another computation unit onboard the jet may determine the slant range of the target from the elevation and the altitude of the jet. The coordinate determiner may at least facilitate ranging of the target quickly enough to allow a pilot sufficient time to evade detection by the target, to destroy the target, or to evade or destroy a projectile fired by the target.

Claims

1. An apparatus, comprising:

a first coordinate determiner operable;

to identify first and second surfaces that each approximately intersect an object, at least one of the surfaces being nonplanar; and

to determine at least two approximate coordinates of the object from the first and second surfaces.

2. The apparatus of claim 1 wherein:

the first surface comprises a surface of a first cone; and

the second surface comprises a surface of a second cone.

3. The apparatus of claim 1 wherein the first coordinate determiner is further operable:

to identify at least one location at which the first and second surfaces approximately intersect each other; and

to determine the at least two approximate coordinates of the object from the at least one location.

4. The apparatus of claim 3 wherein the at least one location comprises multiple locations that define a curve.

5. The apparatus of claim 3 wherein the at least one location comprises multiple locations that define a curve that lies in a plane.

6. The apparatus of claim 1 wherein the at least two coordinates comprise an azimuth and an elevation.

7. The apparatus of claim 3 wherein the coordinate determiner is operable to identify the at least two coordinates from the at least one location and from an estimate of a third coordinate.

8. The apparatus of claim 1 wherein the at least two coordinates comprise an azimuth, an elevation, and a range.

9. The apparatus of claim 3 wherein the coordinate determiner is further operable:

to identify a third surface that approximately intersects the object;

to identify the at least one location as a location at which the first, second, and third surfaces approximately intersect one another; and

to determine as the at least two approximate coordinates of the object three approximate coordinates of the object from the at least one location.

10. The apparatus of claim 1, further comprising a second coordinate determiner operable to determine a third approximate coordinate from at least one of the at least two coordinates and from an estimate of a fourth coordinate.

11. The apparatus of claim 1 wherein the coordinate determiner is further operable to determine an indication of an error in at least one of the at least two determined coordinates.

12. The apparatus of claim 1, further comprising:

wherein the coordinate determiner is further operable to determine a first indication of an error in at least one of the at least two determined coordinates; and

an error calculator operable to calculate from the first indication of an error a second indication of an error in a third approximate coordinate.

13. The apparatus of claim 1 wherein the first coordinate determiner is operable:

to identify the first surface from a first received signal;

to identify the second surface from a second received signal.

14. The apparatus of claim 1 wherein the first coordinate determiner is operable:

to identify the first surface from a first signal received from a first antenna array;

to identify the second surface from a second signal received from a second antenna array.

15. The apparatus of claim 1 wherein the first coordinate determiner is operable:

to identify the first surface from a first signal received from a first interferometer;

to identify the second surface from a second signal received from a second interferometer.

16. A vehicle, comprising:

a first coordinate determiner operable;

to identify first and second surfaces that each approximately intersect an object, at least one of the surfaces being nonplanar; and

to determine at least two approximate coordinates of the object from the first and second surfaces.

20. The system of claim 16 wherein the vehicle comprises an airplane.

17. A system, comprising:

a vehicle, comprising;

a first coordinate determiner operable;

to identify from a first signal a first surface that approximately intersects an object;

to identify from a second signal a second surface that approximately intersects the object, at least one of the first and second surfaces being nonplanar; and

to determine at least two approximate coordinates of the object from the first and second surfaces; and

first and second interferometers secured to the vehicle and respectively operable to generate the first and second signals in response to the object.

18. The system of claim 17 wherein the first and second interferometers are respectively operable to generate the first and second signals in response to a third signal emanating from the object.

19. The system of claim 17 wherein the first and second interferometers are respectively operable to generate the first and second signals in response to a third signal generated by the object.

21. A method, comprising:

identifying first and second surfaces that each approximately intersect an object, at least one of the surfaces being three-dimensional; and

determining at least two approximate coordinates of the object from the first and second surfaces.

22. The method of claim 21 wherein determining at least two coordinates comprises:

identifying at least one location at which the first and second surfaces approximately intersect; and

determining the at least two approximate coordinates from the at least one location.

23. The method of claim 21 wherein determining the at least two approximate coordinates comprises determining the at least two coordinates from a first equation that defines at least a portion of the first surface and from a second equation that defines at least a portion of the second surface.

24. The method of claim 21, further comprising:

receiving a signal from the object with a first antenna array;

determining a first approximate direction of the object relative to the first array; and

wherein identifying the first surface comprises identifying the first surface from the first direction.

25. The method of claim 24, further comprising:

receiving the signal from the object with a second antenna array;

determining a second approximate direction of the object relative to the second array; and

wherein identifying the second surface comprises identifying the second surface from the second direction.

26. The method of claim 21, further comprising:

identifying a third surface that approximately intersects the object;

wherein determining the at least two coordinates comprises determining three approximate coordinates of the object from the first, second, and third surfaces.

27. A computer-readable medium storing program instructions that when executed by a processor cause the processor:

to identify first and second surfaces that each approximately intersect an object, at least one of the surfaces being three-dimensional; and

to determine at least two approximate coordinates of the object from the first and second surfaces.

28. A method, comprising:

identifying first and second angles of first and second cones having surfaces that each approximately intersect an object; and

determining at least two approximate coordinates of the object from the first and second angles.