Phased array antenna beam tracking with difference patterns

• US 7,450,068 B2
• Filed: 11/20/2006
• Issued: 11/11/2008
• Est. Priority Date: 11/20/2006
• Status: Expired due to Fees

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Voyce, Kenneth G., Chen, Ming, Curry, Mark A.
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): LIU, HARRY K
• Application Number:
  US11/602,015
• Publication Number:
  US 20080117105A1
• Time in Patent Office: 722 Days
• Field of Search: 342/383, 342/427, 342/78, 342/79, 342/90, 342/133, 342/139, 342/140
• 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 subarray, 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 analog RF 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 RF 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 analog RF 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 analog RF output and the second array sum analog output, the combining network for generating a combining network output comprising;

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

an analog RF 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 analog RF array output and an output of the phased array antenna; and

a second receiver, communicatively coupled to the analog RF 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 analog RF 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 analog RF 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 analog RF output and the third subarray analog RF output, and a sum of the second subarray analog RF output and the fourth subarray analog RF output (A−

C)+(B−

D) and a second angle component computed as a difference of the sum of the first subarray analog RF output and the third subarray analog RF 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 analog RF output (A);

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

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

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

C);

a second hybrid combiner having

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

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

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

a second hybrid combiner second output producing a difference between the second subarray analog RF output and the fourth subarray analog RF 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 analog RF 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 signal; 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 subarray analog RF 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 subarray summer, coupled to each of the elements in the seventh group of elements, the seventh subarray summer for generating a seventh subarray analog RF 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 subarray analog RF output (H) from the sum of 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 subarray, 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, thy sixth subarray is disposed adjacent the fourth subarray and the eighth subarray, the seventh subarray is disposed adjacent the fourth subarray, the fourth 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 analog RF output and the third subarray analog RF output, and a sum of the second subarray analog RF output and the fourth subarray analog RF output (A−

C)+(B−

D);

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

G)+(F−

H); and

the second angle component computed as a difference of

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

a sum of the third subarray analog RF output and the fourth subarray analog RE output and a sum of the seventh subway analog RF output and the eighth subarray analog RF 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 analog RF 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 subarray analog RF 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 analog RF output and the fourth subarray analog RF output (A−

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

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

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

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

C);

a second hybrid combiner having

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

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

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

a second hybrid combiner second output producing a difference between the second subarray analog RF output and the fourth subarray analog RF 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 a digitized version of the error signal to direct a transmitting antenna sensitive axis toward the source.

8. 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 m is the number of columns, and wherein n≧

2 and m≧

.

9. 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 analog RF error signal proportional to the angle, comprising:

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

m) elements wherein n≧

2 and m≧

2;

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

m) elements wherein n≧

2 and m≧

2;

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

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

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

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

generating a transmitting antenna command from a digitized version of the received error signal to direct a transmitting antenna sensitive axis toward the source.

10. The method of claim 9, wherein:

the method further comprises the steps of;

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

m) elements wherein n≧

2 and m≧

2;

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

in) elements wherein n≧

2 and m≧

2;

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

summing the analog RF output of the first group of elements in the first subarray, the analog RF output of the second group of elements in the second subarray, the analog RF output of the third group of elements in the third subarray, and the analog RF output of the fourth group of elements in the fourth subarray;

the analog RF error signal comprises a first angle component and a second angle component and the step of differencing the analog RF output of the first group of elements in the first subarray and the analog RF 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 analog RF output of the first group of elements in the first subarray and the analog RF output of the third group of elements in the third subarray, and the difference between the analog RF output of the second group of elements in the second subarray and the analog RF output of the fourth group of elements in the fourth subarray to generate the first angle component; and

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

11. The method of claim 9, wherein:

the method further comprises the steps of;

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

m) elements wherein n≧

2 and m≧

2;

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

m) elements wherein n≧

2 and m≧

2;

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

m) elements wherein n≧

2 and m≧

2;

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

m) elements wherein n≧

2 and m≧

2;

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

m) elements wherein n≧

2 and m≧

2;

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

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

the analog RF error signal comprises a first angle component and a second angle component and the step of differencing the analog RF output of the first group of elements in the first subarray and the analog RF 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 analog RF output of the first group of elements in the first subarray and the analog RF output of the third group of elements in the third subarray, the difference between the analog RF output of the second group of elements in the second subarray and the analog RF output of the fourth group of elements in the fourth subarray;

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

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

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

12. The method of claim 9, wherein:

the method further comprises the steps of;

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

m) elements wherein n≧

2 and m≧

2;

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

summing the analog RF output of the first group of elements in the first subarray, the analog RF output of the second group of elements in the second subarray, the analog RF output of the third group of elements in the third subarray, and the analog RF output of the fourth group of elements in the fourth analog subarray;

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

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

13. The method of claim 9, 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. 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 analog RF error signal proportional to the angle, comprising:

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

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

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

means for receiving the analog RF 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.

15. The apparatus of claim 14, wherein;

the apparatus further comprises;

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

means for summing the analog RF output of the first group of elements in the first subarray, the analog RF output of the second group of elements in the second subarray, the analog RF output of the third group of elements in the third subarray, and the analog RF 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 analog RF output of the first group of elements in the first subarray and the analog RF output of the second group of elements in the second subarray to generate the error signal comprises;

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

16. The apparatus of claim 14, wherein:

the apparatus further comprises;

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

m) elements wherein n≧

2 and m≧

2;

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

means for summing the analog RF output of the first group of elements in the first subarray, the analog RF output of the second group of elements in the second subarray, the analog RF output of the third group of elements in the third subarray, the analog RF output of the fourth group of elements in the fourth subarray, the analog RF output of the fifth group of elements in the fifth subarray, the analog RF output of the sixth group of elements in the sixth subarray, the analog RF output of the seventh group of elements in the seventh subarray, and the analog RF 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 analog RF output of the first group of elements in the first subarray and the analog RF output of the second group of elements in the second subarray to generate the error signal comprises;

means for summing a difference between the analog RF output of the first group of elements in the first subarray and the analog RF output of the third group of elements in the third subarray, the difference between the analog RF output of the second group of elements in the second subarray and the analog RF output of the fourth group of elements in the fourth subarray, a difference between the analog RF output of the fifth group of elements in the fifth subarray and the analog RF output of the seventh group of elements in the seventh subarray, and a difference between the analog RF output of the sixth group of elements in the sixth subarray and the analog RF 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 analog RF output of the first group of elements in the first subarray and the analog RF output of the third group of elements in the third subarray, a sum of the analog RF output of the second group of elements in the second subarray and the analog RF output of the fourth group of elements in the fourth subarray, a sum of the analog RF output of the fifth group of elements in the fifth subarray and the analog RF output of the sixth group of elements in the sixth subarray, and a sum of the analog RF output of the seventh group of elements in the seventh subarray and the analog RF output of the eighth group of elements in the eighth subarray to generate the first angle component.

17. The apparatus of claim 14, wherein:

the apparatus further comprises;

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

means for summing the analog RF output of the first group of elements in the first subarray, the analog RF output of the second group of elements in the second subarray, the analog RF output of the third group of elements in the third subarray, and the analog RF 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 analog RF output of the first group of elements in the first subarray and the analog RF output of the second group of elements in the second subarray to generate the analog RF error signal comprises;

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