Phased array antenna beam tracking with difference patterns

• US 20080117105A1
• Filed: 11/20/2006
• Published: 05/22/2008
• Est. Priority Date: 11/20/2006
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Voyce, Kenneth G., Chen, Ming, Curry, Mark A.
• Granted Patent: US 7,450,068 B2
• Time in Patent Office: Days
• US Class Current: 342/427
• CPC Class Codes: G01S 3/22 derived from different combinations of signals from separate antennas, e.g. comparing sum with difference
• CPC Class Codes: G01S 3/56 Conical-scan beam systems using signals indicative of the deviation of the direction of reception from the scan axis
• CPC Class Codes: H01Q 21/062 using dipole aerials; H01Q21/067, H01Q21/068 take precedence
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence

Abstract

A system and method for using a phased array antenna to concurrently receive an RF signal transmitted by a remote transmitter, to determine the angular location of the remote transmitter using the transmitted signal, and to use that angular location to direct a transmit antenna to transmit information in the direction of the transmitter is disclosed.

Claims

1. A device for receiving a radio frequency (RF) communication signal transmitted from a source and concurrently determining the direction of the source, comprising:

a phased array antenna disposed in a plane, the phased array antenna for receiving the communication signal at an angle offset from a boresight vector extending from the plane, the phased array antenna comprising;

a first sub array, having

a first group of elements, each element of the first group of elements for receiving the RF signal; and

a first subarray summer, coupled to each of the elements in the first group of elements, the first subarray summer for generating a first subarray output (A) from the sum of the RF signals received by each of the elements in the first group of elements;

a second subarray, having

a second group of elements, each element of the second group of elements for receiving the RE signal; and

a second subarray summer, coupled to each of the elements in the first group of elements, the second array summer for generating a second sub array output (B) from the sum of the RF signals received by each of the elements in the second group of elements;

a combining network, coupled to the first array sum output and the second array sum output, the combining network for generating a combining network output comprising;

an array output representing the received signal as the sum of the first subarray output, the second subarray output (A+B); and

an error signal proportional to the angle offset from the boresight vector extending from the plane, the error signal generated as a difference between the first subarray output and the second subarray output;

a first receiver, communicatively coupled to the array output and an output of the phased array antenna; and

a second receiver, communicatively coupled to the error signal and the array controller.

2. The apparatus of claim 1, further comprising:

a third subarray, having

a third group of elements, each element of the third group of elements for receiving the RF signal; and

a third subarray summer, coupled to each of the elements in the third group of elements, the third subarray summer for generating a third subarray output (C) from the sum of the RF signals received by each of the elements in the third group of elements;

a fourth subarray, having

a fourth group of elements, each element of the fourth group of elements for receiving the RF signal; and

a fourth subarray summer, coupled to each of the elements in the first group of elements, the fourth array summer for generating a fourth sub array output (D)) from the sum of the RF signals received by each of the elements in the fourth group of elements; and

wherein the third subarray and the fourth subarray are of (n×

m) dimension wherein n is the number of rows of elements and m is the number of columns, and wherein n≧

2 and m≧

2;

wherein the first subarray is disposed adjacent the second subarray and the third subarray, the second subarray is disposed adjacent the first subarray and the fourth subarray, the third subarray is disposed adjacent the first subarray and the fourth subarray, and the fourth subarray is disposed adjacent the second and the third subarray;

wherein the angle comprises a first angle component computed by the combining network as a sum of the difference between a sum of the first subarray output and the third subarray output, and a sum of the second subarray output and the fourth subarray output (A−

C)+(B−

D) and a second angle component computed as a difference of the sum of the first subarray output and the third subarray output and a sum o of the second subarray output and the fourth subarray output (A+C)−

(B+D).

3. The apparatus of claim 2, wherein the combining network comprises:

a first hybrid combiner, having

a first hybrid combiner first input coupled to the first subarray output (A);

a first hybrid combiner second input coupled to the third subarray output (C);

a first hybrid combiner first output producing a sum of the first subarray output and the third subarray output (A+C); and

a first hybrid combiner second output producing a difference between the first subarray output and the third subarray output (A−

C);

a second hybrid combiner having

a second hybrid combiner first input coupled to the second subarray output (B);

a second hybrid combiner second input coupled to the fourth subarray output (D);

a second hybrid combiner first output producing a sum of the second subarray output and the fourth subarray output (B+D); and

a second hybrid combiner second output producing a difference between the second subarray output and the fourth subarray output (B−

D);

a third hybrid combiner having

a third hybrid combiner first input coupled to the first hybrid combiner first output (A+C);

a third hybrid combiner second input coupled to the second hybrid combiner first output (B+D);

a third hybrid combiner first output producing a sum of the third hybrid combiner first input and the third hybrid combiner second input (A+B)+(C+D);

a third hybrid combiner second output producing a difference of the third hybrid combiner first input and the third hybrid combiner second input (A+B)−

(C+D).

a fourth hybrid combiner, having

a fourth hybrid combiner first input coupled to the first hybrid combiner second output (A−

C);

a fourth hybrid combiner second input coupled to the second hybrid combiner second output (B−

D);

a fourth hybrid combiner output producing a sum of the fourth hybrid combiner first input and the fourth hybrid comber second input (A−

C)+(B−

D).

4. The apparatus of claim 2, further comprising:

a fourth subarray, having

a fifth group of elements, each element of the fifth group of elements for receiving the RF signal; and

a fifth subarray summer, coupled to each of the elements in the fifth group of elements, the fifth subarray summer for generating a fifth subarray output (E) from the sum of the RF signals received by each of the elements in the fifth group of elements;

a sixth subarray, having

a sixth group of elements, each element of the sixth group of elements for receiving the RF signals; and

a sixth subarray summer, coupled to each of the elements in the first group of elements, the sixth array summer for generating a sixth sub may output (F) from the sum of the RF signals received by each of the elements in the sixth group of elements; and

a seventh subarray, having

a seventh group of elements, each element of the seventh group of elements for receiving the RF signal; and

a seventh subway summer, coupled to each of the elements in the seventh group of elements, the seventh subarray summer for generating a seventh subarray output (G) from the sum of the RF signals received by each of the elements in the seventh group of elements;

a eighth subarray, having

a eighth group of elements, each element of the eighth group of elements for receiving the RF signal; and

a eighth subarray summer, coupled to each of the elements in the first group of elements, the eighth array summer for generating a eighth sub array output (H) from the sum the RF signals received by each of the elements in the eighth group of elements; and

wherein

the fourth subarray, the sixth subarray, the seventh subway, and the eighth subarray are of (n×

m) dimension wherein n is the number of rows of elements and m is the number of columns, and wherein n≧

2 and m≧

2;

the fourth subarray is disposed adjacent the fourth subarray, the sixth subarray, and the seventh subarray, the sixth subarray is disposed adjacent the fourth subarray and the eighth subarray, the seventh sub array is disposed adjacent the fourth subarray, the forth subarray and the eighth subarray, and the eighth subarray is disposed adjacent the sixth and the seventh subarray;

the first angle component is computed as difference of

a sum of the difference between the first subarray output and the third subarray output, and a sum of the second subarray output and the fourth subarray output (A−

C)+(B−

D);

a sum of a difference between the fifth subarray output and the seventh subarray output and a difference between the sixth subarray output and the eighth subarray output ((E−

G)+(F−

H); and

the second angle component computed as a difference of

a sum of the first sub array output and the second subarray output and a sum of the fifth subarray output and the sixth subarray output (A+B)+(E+F); and

a sum of the third subarray output and the fourth subarray output and a sum of the seventh subarray output and the eighth subarray output (C+D)+(G+H).

5. The apparatus of claim 1, further comprising:

a third subarray, having

a third group of elements, each element of the third group of elements for receiving the RF signal; and

a third subarray summer, coupled to each of the elements in the third group of elements, the third subarray summer for generating a third subarray output (C) from the sum of the RF signals received by each of the elements in the third group of elements;

a fourth subarray, having

a fourth group of elements, each element of the fourth group of elements for receiving the RF signal; and

a fourth subarray summer, coupled to each of the elements in the first group of elements, the fourth array summer for generating a fourth sub array output (D) from the sum of the RF signals received by each of the elements in the fourth group of elements; and

wherein the third subarray and the fourth subarray are of n×

m dimension wherein n is the number of rows of elements and m is the number of columns, and wherein n≧

2 and m≧

2;

wherein the first subarray is disposed adjacent the second subarray and the third subarray, the second subarray is disposed adjacent the first subarray and the fourth subarray, the third subarray is disposed adjacent the first subarray and the fourth subarray, and the fourth subarray is disposed adjacent the second and the third subarray;

wherein the angle comprises a first angle component computed as a difference between the first subarray output and the fourth subarray output (A−

D), and a second angle component computed as a difference between the second subarray output and the third subarray output (B−

C).

6. The apparatus of claim 2, wherein the combining network comprises:

a first hybrid combiner, having

a first hybrid combiner first input coupled to the second subarray output (B);

a first hybrid combiner second input coupled to the third subarray output (C);

a first hybrid combiner first output producing a sum of the second subarray output and the third subarray output (B+C); and

a first hybrid combiner second output producing a difference between the second subarray output and the third subarray output (B−

C);

a second hybrid combiner having

a second hybrid combiner first input coupled to the first subarray output (A);

a second hybrid combiner second input coupled to the fourth subarray output (D);

a second hybrid combiner first output producing a sum of the first subarray output and the fourth subarray output (A+D); and

a second hybrid combiner second output producing a difference between the second subarray output and the fourth subarray output (B−

D);

a third hybrid combiner having

a third hybrid combiner first input coupled to the first hybrid combiner first output (B+C);

a third hybrid combiner second input coupled to the second hybrid combiner first output (A+D);

a third hybrid combiner first output producing a sum of the third hybrid combiner first input and the third hybrid combiner second input (A+B)+(C+D).

7. The apparatus of claim 1, further comprising:

an array controller, coupled to the combining network, the array controller for generating a transmitting antenna command from the error signal to direct a transmitting antenna sensitive axis toward the source.

9. The apparatus of claim 1, wherein the first subarray and the second subarray are of (n×

m) dimension wherein n is the number of rows of elements and in is the number of columns, and wherein n≧

2 and m≧

2.

8. (canceled)

10. In a phased array antenna disposed in a plane, a method for receiving a radio frequency signal transmitted from a source offset from a boresight vector extending from the plane and concurrently generating an error signal proportional to the angle, comprising:

summing an output of a first group of elements in a first subarray having (n×

m) elements wherein n≧

2 and m 2;

summing an output of a second group of elements in a second subarray having (n×

m) elements wherein n≧

2 and m≧

2;

summing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to produce an array output representing the received radio frequency signal; and

differencing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to generate the error signal;

receiving the first array output with a first receiver to generate an output signal;

receiving the error signal output with a second and receiver generate a received error signal;

generating a transmitting antenna command in the received error signal to direct a transmitting antenna sensitive axis toward the source.

11. The method of claim 10, wherein:

the method further comprises the steps of;

summing an output of a third group of elements in a third subarray having (n×

m) elements wherein n≧

2 and m≧

2;

summing an output of a fourth group of elements in a fourth subarray having (n×

m) elements wherein n≧

2 and m≧

2;

the step of summing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to produce an array output representing the received radio frequency signal comprises the step of

summing the output of the first group of elements in the first subarray, the output of the second group of elements in the second subarray, the output of the third group of elements in the third subarray, and the output of the fourth group of elements in the fourth subarray.

the error signal comprises a first angle component and a second angle component and the step of differencing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to generate the error signal comprises the step of

summing a difference between the output of the first group of elements in the first subarray and the output of the third group of elements in the third subarray, and the difference between the output of the second group of elements in the second subarray and the output of the fourth group of elements in the fourth subarray to generate the first angle component; and

differencing a sum of the output of the first group of elements in the first subarray and the output of the third group of elements in the third subarray, and a sum of the output of the second group of elements in the second subarray and the output of the fourth group of elements in the fourth subarray to generate the first angle component.

12. The method of claim 10, wherein:

the method further comprises the steps of;

summing an output of a third group of elements in a third subarray having (n×

m) elements wherein n≧

2 and m≧

2;

summing an output of a fourth group of elements in a fourth subarray having (n×

m) elements wherein n≧

2 and m≧

2;

summing an output of a fifth group of elements in a fourth subarray having (n×

m) elements wherein n≧

2 and m≧

2;

summing an output of a sixth group of elements in a sixth subarray having (n×

m) elements wherein n≧

2 and inn≧

2 ;

summing an output of a seventh group of elements in a seventh subarray having (n×

m) elements wherein n≧

2 and m≧

2;

summing an output of an eighth group of elements in an eighth subarray having (n×

m) elements wherein n≧

2 and m≧

2;

the step of summing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to produce an array comprises the step of

summing the output of the first group of elements in the first subarray, the output of the second group of elements in the second subarray, the output of the third group of elements in the third subarray, the output of the fourth group of elements in the fourth subarray, the output of the fifth group of elements in the fifth subarray, the output of the sixth group of elements in the sixth subarray, the output of the seventh group of elements in the seventh subarray, and the output of the eighth group of elements in the eighth subarray;

the error signal comprises a first angle component and a second angle component and the step of differencing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to generate the error signal comprises the steps of

summing a difference between the output of the first group of elements in the first subarray and the output of the third group of elements in the third subarray, the difference between the output of the second group of elements in the second subarray and the output of the fourth group of elements in the fourth subarray;

a difference between the output of the fifth group of elements in the fifth subarray and the output of the seventh group of elements in the seventh subarray, and a difference between the output of the sixth group of elements in the sixth subarray and the output of the eighth group of elements in the eighth subarray to generate the first angle component; and

differencing a sum of the output of the first group of elements in the first subarray and the output of the third group of elements in the third subarray, a sum of the output of the second group of elements in the second subarray and the output of the fourth group of elements in the fourth subarray, a sum of the output of the fifth group of elements in the fifth subarray and the sixth group of elements in the sixth subarray; and

a sum of the output of the seventh group of elements in the seventh subarray and the eighth group of elements in the eighth subarray to generate the first angle component.

13. The method of claim 10, wherein:

the method further comprises the steps of;

summing an output of a third group of elements in a third subarray having (n×

m) elements wherein n n≧

2 and m 2;

summing an output of a fourth group of elements in a fourth subarray having (n×

m) elements wherein n≧

2 and m≧

2;

the step of summing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to produce an array comprises the step of

summing the output of the first group of elements in the first subarray, the output of the second group of elements in the second subarray, the output of the third group of elements in the third subarray, and the output of the fourth group of elements in the fourth subarray.

the error signal comprises a first angle component and a second angle component and the step of differencing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to generate the error signal comprises the step of;

differencing the output of the first group of elements in the first subarray and the output of the fourth group of elements in the fourth subarray to generate the first angle component and differencing the output of the second group of elements in the second array and the third group of elements in the third array to generate the second angle component.

15. The method of claim 10, wherein the first subarray and the second subarray are of (n×

m) dimension wherein n is the number of rows of elements and m is the number of columns, and wherein n≧

2 and m≧

2.

14. (canceled)

16. In a phased array antenna disposed in a plane, the phased array antenna for receiving a radio frequency signal transmitted from a source offset from a boresight vector extending From the plane, an apparatus for generating an error signal proportional to the angle, comprising:

means for summing an output of a first group of elements in a first subarray having (n×

m) elements wherein n≧

2 and m≧

2;

means for summing an output of a second group of elements in a second subarray having (n×

m) elements wherein n≧

2 and m≧

2;

means for summing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to produce an array output;

means for differencing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to generate the error signal and

means for receiving the first array output with a first receiver to generate an output signal;

means for receiving the error signal output with a second receiver generate a received error signal;

means for generating a transmitting antenna command from the received error signal to direct a transmitting antenna sensitive axis toward the source.

17. The apparatus of claim 16, wherein:

the apparatus farther comprises;

means for summing an output of a third group of elements in a third subarray having (n×

m) elements wherein n≧

2 and m≧

2;

means for summing an output of a fourth group of elements in a fourth subarray having (n×

m) elements wherein n≧

2 and m≧

2;

the means for summing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to produce an array comprises;

means for summing the output of the first group of elements in the first subarray, the output of the second group of elements in the second subarray, the output of the third group of elements in the third subway, and the output of the fourth group of elements in the fourth subway.

the error signal comprises a first angle component and a second angle component and the means for differencing the output of the first group of elements in the first subway and the output of the second group of elements in the second subway to generate the error signal comprises;

means for summing a difference between the output of the first group of elements in the first subarray and the output of the third group of elements in the third subarray, and the difference between the output of the second group of elements in the second subarray and the output of the fourth group of elements in the fourth subarray to generate the first angle component; and

means for differencing a sum of the output of the first group of elements in the first subarray and the output of the third group of elements in the third subarray, and a sum of the output of the second group of elements in the second subway and the output of the fourth group of elements in the fourth subarray to generate the first angle component

18. The apparatus of claim 16, wherein:

the apparatus further comprises;

means for summing an output of a third group of elements in a third subarray having (n×

m) elements wherein n≧

2 and m≧

2;

means for summing an output of a fourth group of elements in a fourth subarray having (n×

m) elements wherein n≧

2 and m≧

2;

means for summing an output of a fifth group of elements in a fifth subarray having (n×

m) elements wherein n≧

2 and m≧

2;

means for summing an output of a sixth group of elements in a sixth subarray having (n×

m) elements wherein n≧

2 and m≧

2;

means for summing an output of a seventh group of elements in a seventh subarray having (n×

m) elements wherein n≧

2 and m≧

2;

means for summing an output of an eighth group of elements in an eight subarray having (n×

m) elements wherein n≧

2 and m≧

2;

the means for summing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to produce an way comprises;

means for summing the output of the first group of elements in the first subarray, the output of the second group of elements in the second subarray, the output of the third group of elements in the third subarray, the output of the fourth group of elements in the fourth subarray, the output of the fifth group of elements in the fifth subarray, the output of the sixth group of elements in the sixth subarray, the output of the seventh group of elements in the seventh subarray, and the output of the eighth group of elements in the eighth subarray;

the error signal comprises a first angle component and a second angle component and the step of differencing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to generate the error signal comprises;

means for summing a difference between the output of the first group of elements in the first subarray and the output of the third group of elements in the third subarray, the difference between the output of the second group of elements in the second subarray and the output of the fourth group of elements in the fourth subarray;

a difference between the output of the fifth group of elements in the fifth subarray and the output of the seventh group of elements in the seventh subarray, and a difference between the output of the sixth group of elements in the sixth subarray and the output of the eighth group of elements in the eighth subarray to generate the first angle component; and

means for differencing a sum of the output of the first group of elements in the first subarray and the output of the third group of elements in the third subarray, a sum of the output of the second group of elements in the second subarray and the output of the fourth group of elements in the fourth subarray, a sum of the output of the fifth group of elements in the fifth subarray and the sixth group of elements in the sixth subarray; and

a sum of the output of the seventh group of elements in the seventh subarray and the eighth group of elements in the eighth subarray to generate the first angle component.

19. The apparatus of claim 16, wherein:

the apparatus further comprises;

means for summing an output of a third group of elements in a third subarray having (n×

m) elements wherein n≧

2 and m≧

2;

means for summing an output of a fourth group of elements in a fourth subarray having (n×

m) elements wherein n≧

2 and m≧

2;

the means for summing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to produce an array comprises;

means for summing the output of the first group of elements in the first subarray, the output of the second group of elements in the second subarray, the output of the third group of elements in the third subarray, and the output of the fourth group of elements in the fourth subarray.

the error signal comprises a first angle component and a second angle component and the means for differencing the output of the first group of elements in the first subarray and the output of the second group of elements in the second subarray to generate the error signal comprises;

means for differencing the output of the first group of elements in the first subarray and the output of the fourth group of elements in the fourth subarray to generate the first angle component and differencing the output of the second group of elements in the second array and the third group of elements in the third array to generate the second angle component.

20. (canceled)