Apparatus and method for automatic antenna beam positioning

• US 5,434,578 A
• Filed: 10/22/1993
• Issued: 07/18/1995
• Est. Priority Date: 10/22/1993
• Status: Expired due to Fees

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Stehlik, Roy R.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US08/139,674
• Time in Patent Office: 634 Days
• Field of Search: 342/380, 342/382, 342/383
• US Class Current: 342/383
• 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 for automatically forming a receive beam being positioned in the direction of a corresponding incoming signal, the system having a known signal corresponding to the incoming signal. The system comprises a plurality, M, of channels, each of the channels collecting the incoming signal and generating a plurality, L, of incoming complex data samples for the incoming signal and a plurality, L, of known complex data samples for the known signal. The system also includes severaly digital beamforming means for forming the receive beam. Each of the digital beamforming means includes means, coupled to the channels, for computing an M by 1 weight vector, W, having several weight elements each corresponding to one of the channels, the computing means including means for solving, for W, the equation, R W=C, where R is an M by M coefficient matrix, an element in the i-th row and the j-th column being an estimate of a value obtained from cross-correlating the incoming complex data sample generated by the i-th channel with the incoming complex data sample of the j-th channel, and where C is an M by 1 constant vector, an element in the i-th row being an estimate of a value obtained from cross-correlating the incoming complex data sample generated by the i-th channel with the known complex data samples. Each of the digital beamforming means further includes multipliers for generating weighted signals, each of the multipliers coupled to a corresponding one of the channels and multiplying one of the weight elements by the incoming complex data samples generated by the corresponding channel, and an adder, coupled to the multipliers, for adding each of the weighted signals.

Claims

1. A system for automatically forming at least one receive beam positioned in the direction of a corresponding at least one incoming signal, said system having at least one known signal corresponding to said at least one incoming signal, said system comprising:

a plurality, M, of channels, each of said plurality of channels collecting said at least one incoming signal and generating a plurality, L, of incoming complex data samples for said at least one incoming signal and a plurality, L, of known complex data samples for said at least one known signal; and

a plurality of digital beamforming means for forming said at least one receive beam, each of said plurality of digital beamforming means including

means, coupled to said plurality of channels, for computing an M by 1 weight vector, W, having a plurality, M, of weight elements each corresponding to one of said plurality of channels, said computing means including means for solving the following equation for W;

space="preserve" listing-type="equation">R W=C,

wherein R is an M by M coefficient matrix, an element in the i-th row and the j-th column of said coefficient matrix being an estimate of a value obtained from cross-correlating the incoming complex data sample generated by the i-th channel with the incoming complex data sample of the j-th channel, and wherein C is an M by 1 constant vector, an element in the i-th row of said constant vector being an estimate of a value obtained from cross-correlating the incoming complex data sample generated by the i-th channel with the plurality of known complex data samples,

a plurality, M, of multipliers for generating a plurality of weighted signals, each of said plurality of multipliers coupled to a corresponding one of said plurality of channels and including means for multiplying one of said plurality of weight elements by said plurality of complex data samples generated by said corresponding channel, and

an adder, coupled to said plurality of multipliers, for adding each of said plurality of weighted signals.

2. The system recited in claim 1, wherein R=X*X^T, X being an M by L data matrix, an element in the i-th row and the j-th column of said data matrix being the j-th incoming complex data sample generated by the i-th channel;

wherein X* is the complex conjugate of X;

wherein X^T is the transpose of X; and

wherein C=X*D, D being an L by 1 data vector of the plurality of known complex data samples.

3. The system recited in claim 1, wherein the at least one incoming signal has a transmission frequency band, and wherein each of the plurality of channels converts the at least one incoming signal from said transmission frequency band to a baseband frequency centered at 0 Hz.

4. The system recited in claim 1, wherein the plurality of weight elements are periodically recomputed by the computing means according to a predetermined frequency.

5. The system recited in claim 4, wherein the predetermined frequency is in the range of 2 Hz to 10 Hz.

6. A method for automatically forming at least one receive beam positioned in the direction of a corresponding at least one incoming signal, said system having at least one known signal corresponding to said at least one incoming signal, said method comprising:

collecting, using a plurality of channels, said at least one incoming signal and generating a plurality, L, of incoming complex data samples for said at least one incoming signal and a plurality, L, of known complex data samples for said at least one known signal; and

digitally forming said at least one receive beam, including

computing an M by 1 weight vector, W, having a plurality, M, of weight elements each corresponding to one of said plurality of channels, including solving for W the equation;

space="preserve" listing-type="equation">R W=C,

wherein R is an M by M coefficient matrix, an element in the i-th row and the j-th column of said coefficient matrix being an estimate of a value obtained from cross-correlating the incoming complex data sample generated by the i-th channel with the incoming complex data sample of the j-th channel, and wherein C is an M by 1 constant vector, an element in the i-th row of said constant vector being an estimate of a value obtained from cross-correlating the incoming complex data sample generated by the i-th channel with the plurality of known complex data samples,

multiplying each of said plurality of weight elements by said plurality of complex data samples generated by said corresponding one of said plurality of channels, and

adding said multiplied weight elements.

7. The method recited in claim 6, wherein R=X*X^T, X being an M by L data matrix, an element in the i-th row and the j-th column of said data matrix being the j-th incoming complex data sample generated by the i-th channel;

wherein X* is the complex conjugate of X;

wherein X^T is the transpose of X; and

wherein C=X*D, D being an L by 1 data vector of said plurality of known complex data samples.

8. The method recited in claim 6, wherein the at least one incoming signal includes a transmission frequency band, and wherein the processing step includes converting the at least one incoming signal from said transmission frequency band to a baseband frequency centered at 0 Hz.

9. The method recited in claim 6, wherein the computing step is periodically performed according to a predetermined frequency.

10. The method recited in claim 9, wherein the predetermined frequency is in the range of 2 Hz to 10 Hz.

11. A system for automatically forming a plurality of receive beams, each of said plurality of receive beams being positioned in the direction of one of a corresponding plurality of incoming signals, said system having a plurality of known signals corresponding to one of said plurality of incoming signals, said system comprising:

a plurality, M, of channels, each of said plurality of channels collecting said plurality of incoming signals and generating a plurality, L, of incoming complex data samples for each of said plurality of incoming signals and a plurality, L, of known complex data samples for each of said plurality of known signals; and

a plurality of digital beamforming means for forming said plurality of receive beams, each of said plurality of digital beamforming means including

means, coupled to said plurality of channels, for computing an M by 1 weight vector, W, having a plurality, M, of weight elements each corresponding to one of said plurality of channels, including means for solving the following equation for W;

space="preserve" listing-type="equation">(X*X.sup.T) W=X*D,

wherein X is an M by L data matrix, an element in the i-th row and the j-th column of said data matrix being the j-th incoming complex data sample generated by the i-th channel, wherein X* is the complex conjugate of X and X^T is the transpose of X, and wherein D is an L by 1 data vector of said plurality of known complex data samples,

a plurality of multipliers for generating a plurality of weighted signals, each of said plurality of multipliers coupled to a corresponding one of said plurality of channels and multiplying one of said plurality of weight elements by said plurality of incoming complex data samples generated by said corresponding one of said plurality of channels, and

an adder, coupled to said plurality of multipliers, for adding each of said plurality of weighted signals.

12. A method for automatically forming a plurality of receive beams, each of said plurality of receive beams being positioned in the direction of one of a plurality of incoming signals, said system having a plurality of known signals each corresponding to one of said plurality of incoming signals, said system comprising:

collecting, using a plurality of channels, said plurality of incoming signals and generating a plurality, L, of incoming complex data samples for each of said plurality of incoming signals and a plurality, L, of known complex data samples for each of said plurality of known signals; and

digitally forming said plurality of receive beams, including

computing, for each of said plurality of incoming signals, an M by 1 weight vector, W, having a plurality of weight elements each corresponding to one of said plurality of channels, including solving the following equation for W;

space="preserve" listing-type="equation">(X*X.sup.T) W=X*D,

wherein X is an M by L data matrix, an element in the i-th row and the j-th column of said data matrix being the j-th incoming complex data sample generated by the i-th channel, wherein X^* is the complex conjugate of X and X^T is the transpose of X, and wherein D is an L by 1 data vector of said plurality of known complex data samples,

multiplying, for each of said plurality of incoming signals, each of said plurality of weight elements by said plurality of incoming complex data samples generated by said corresponding one of said plurality of channels, and

adding, for each of said plurality of incoming signals, each of said multiplied weight elements.