SYSTEMS AND METHODS FOR PROVIDING IMPROVED TCAS BEARING MEASUREMENT

• US 20130325314A1
• Filed: 02/25/2011
• Published: 12/05/2013
• Est. Priority Date: 02/25/2011
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Wang, Guoqing, Xuan, Jianqiang
• Granted Patent: US 8,965,680 B2
• Time in Patent Office: Days
• US Class Current: 701/301
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
• CPC Class Codes: G01S 13/933 of aircraft or spacecraft
• CPC Class Codes: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured
• CPC Class Codes: G08G 5/04 Anti-collision systems
• CPC Class Codes: H01Q 1/28 Adaptation for use in or on aircraft, missiles, satellites, or balloons
• CPC Class Codes: H01Q 21/20 the units being spaced along or adjacent to a curvilinear path slotted waveguide arrays H01Q21/005; circularly or helically slotted waveguides H01Q21/0062
• CPC Class Codes: H01Q 21/293 one unit or more being an array of identical aerial elements adaptive arrays H01Q3/2605
• CPC Class Codes: H01Q 3/267 Phased-array testing or checking devices

Abstract

Systems and methods for improving bearing accuracy in a Traffic Collision Avoidance System (TCAS) environment. An interrogation signal is transmitted from an array of antenna elements. A response to the transmitted interrogation signal from a target is received at a first pair of elements of the array. The first pair of elements is separated by at most ½λ of the response signal. A processor determines coarse bearing of the received response. A second pair of elements of the array of antenna elements receives a response to the interrogation signal. The second pair of elements is separated by approximately Nλ of the response signal. N is an integer not equal to zero. A first bearing value to the target is determined based on the determined coarse bearing and the received response at the second pair of elements. The array is mounted on an aircraft or on a ground installation.

Claims

1. A method comprising:

transmitting an interrogation signal from at least a portion of an array of antenna elements;

receiving a first response to the transmitted interrogation signal from a target at at least a first pair of elements of the array of antenna elements, the at least first pair of elements being separated by at most ½

λ

of the first response signal;

determining a coarse bearing of the received first response;

receiving a second response to the transmitted interrogation signal at at least a second pair of elements of the array of antenna elements, the at least second pair of elements being separated by approximately Nλ

of the response signal, N being an integer not equal to zero; and

determining a first bearing value for the target based on the coarse bearing and the received second response at the at least second pair of elements.

2. The method of claim 1, wherein the at least first pair of elements comprises two pair of elements, the two pair of elements sharing a common element, the axes linking the elements in each of the two pair of elements being perpendicular to each other and

wherein the at least second pair of elements comprises a single pair of elements, one of the elements of the pair of elements of the at least second pair of elements being the common element.

3. The method of claim 2, wherein all the pairs of elements of the array of antenna elements are located in approximately the same plane on an aircraft.

4. The method of claim 3, further comprising:

transmitting an interrogation signal from a second array of antenna elements;

receiving a third response to the transmitted interrogation signal from a target at at least a first pair of elements of the second array of antenna elements, the at least first pair of elements being separated by at most ½

λ

of the response signal;

determining a coarse bearing of the received third response;

receiving a fourth response to the transmitted interrogation signal at at least a second pair of elements of the second array of antenna elements, the at least second pair of elements being separated by approximately Nλ

of the response signal, N being an integer not equal to zero;

determining a second bearing value for the target based on the coarse bearing associated with the received third response and the received fourth response at the second pair of elements; and

determining a third bearing value based on a phase difference derived from the second bearing value and a phase difference derived from the first bearing value.

5. The method of claim 4, wherein the at least first pair of elements of the second array of antenna elements comprises two pair of elements, the two pair of elements sharing a common element, the axes linking the elements in each of the two pair of elements being perpendicular to each other and

wherein the at least second pair of elements of the second array of antenna elements comprises a pair of elements, one of the elements of the pair of elements of the at least second pair of elements being the common element.

6. The method of claim 5, wherein the pairs of elements of the at least first pair of elements and of the at least second pair of elements of the second array of antenna elements are located in approximately the same plane on an aircraft, wherein the first array of antenna elements is located on a top of the aircraft and the second array of antenna elements is located on a bottom of the aircraft.

7. The method of claim 1, wherein the at least first pair of elements of the array of antenna elements comprises two pair of elements being separated by at most ½

λ

of the response signal and wherein the at least second pair of elements of the array of antenna elements comprises two pair of elements being separated by approximately Nλ

of the response signal, N being an integer not equal to zero.

8. The method of claim 7, wherein the first and second pairs of elements of the array of antenna elements are located in the same plane.

9. The method of claim 8, wherein the first and second pairs of elements of the array of antenna elements are located on the ground and the second pair of elements surrounds the first pair of elements.

10. A system comprising:

an array of antenna elements comprising at least a first pair of elements and at least a second pair of elements, the at least first pair of elements are separated by at most ½

λ

of the response signal, the at least second pair of elements are separated by approximately Nλ

of the response signal, N being an integer not equal to zero;

a means for transmitting an interrogation signal from at least a portion of the array of antenna elements;

a means for receiving a response to the transmitted interrogation signal from a target at the at least first pair of elements;

a processor configured to determine coarse bearing of the received response; and

a means for receiving a response to the transmitted interrogation signal at the at least second pair of elements,

wherein the processor is further configured to determine a first bearing value for the target based on the determined coarse bearing and the received response at the at least second pair of elements.

11. The system of claim 10, wherein the at least first pair of elements comprises two pairs of elements, the two pairs of elements share a common element, the axes linking the elements in each of the two pairs of elements being perpendicular to each other and

wherein the at least second pair of elements comprises a pair of elements, one of the elements of the pair of elements of the at least second pair of elements being the common element.

12. The system of claim 11, wherein all the pairs of two pairs of elements of the at least first pair of elements and the pair of elements of the at least second pair of elements are located in approximately in the same plane on an aircraft.

13. The system of claim 12, further comprising:

a second array of antenna elements comprising at least a first pair of elements and at least a second pair of elements, the at least first pair of elements are separated by at most ½

λ

of the response signal, the at least second pair of elements are separated by approximately Nλ

of the response signal, N being an integer not equal to zero;

a means for transmitting an interrogation signal from at least a portion of a second array of antenna elements;

a means for receiving a response to the transmitted interrogation signal from a target at the at least first pair of elements of the second array of antenna elements;

a means for receiving a response to the transmitted interrogation signal at the at least second pair of elements of the second array of antenna elements;

a processor configured to;

determine coarse bearing of the received response at the at least first pair of elements of the second array of antenna elements;

determine a second bearing value for the target based on the determined coarse bearing associated with the second array of antenna elements and the received response at the second pair of elements of the second array of antenna elements; and

determine a third bearing value based on a phase difference derived from the second bearing value and a phase difference derived from the first bearing value.

14. The system of claim 13, wherein the at least first pair of elements of the second array of antenna elements comprises two pairs of elements, the two pairs of elements share a common element, the axes linking the elements in each of the two pairs of elements are perpendicular to each other and wherein the at least second pair of elements of the second array of antenna elements comprises a pair of elements, one of the elements of the pair of elements of the at least second pair of elements being the common element.

15. The system of claim 14, wherein the pairs of elements of the at least first pair of elements and of the at least second pair of elements of the second array of antenna elements are located in approximately the same plane on an aircraft, wherein the first array of antenna elements is located on a top of the aircraft and the second array of antenna elements is located on a bottom of the aircraft.

16. The system of claim 10, wherein the at least first pair of elements of the array of antenna elements comprises two pairs of elements being separated by at most ½

λ

of the response signal and wherein the at least first pair of elements of the array of antenna elements comprises two pairs of elements being separated by approximately Nλ

of the response signal, N being an integer not equal to zero.

17. The system of claim 16, wherein the first and second pair of elements of the array of antenna elements are located in the same plane.

18. The system of claim 17, wherein the first and second pair of elements of the array of antenna elements are located on the ground.