Broad beam antenna design for a tilted phased array with platform motion
First Claim
1. In a beamforming apparatus for a phased array antenna, a method for beamforming in a phased array antenna having a total aperture, comprising:
- receiving a specified beam steering vector (BSV);
determining a number of concentric sub-apertures based upon a beam spoiling vector associated with said BSV;
dividing the total aperture into the determined number of concentric sub-apertures;
computing a spoiled BSV for at least one of two orthogonal co-planar dimensions perpendicular to the direction of propagation of a transmit wavefront based on the BSV;
applying the spoiled BSV in divergent directions for each sub-aperture by;
for each element i in each of said sub-apertures, computing a beam steering phase coefficient, where said beam steering phase coefficient is determined by the equation
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Accused Products
Abstract
Embodiments of the present invention are directed to techniques and systems for modifying the transmit beam of a phased array antenna in order to effect a shape change in the beam that pre-compensates for platform motion and clutter considerations in the local environment. The techniques and systems herein disclosed take advantage of the phase controlling capability of phased array antennas to adjust the performance of each element in a way that de-focuses or spoils the transmit beam. This spoiling, in turn, enables the transmission of a broader, tailored beam that provides illumination over an area that would otherwise require multiple scans from narrow transmit beams. The techniques described provide a closed-form solution that sacrifices some antenna pattern efficiency in exchange for greatly reduced computational complexity over prior art, optimal search techniques.
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Citations
15 Claims
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1. In a beamforming apparatus for a phased array antenna, a method for beamforming in a phased array antenna having a total aperture, comprising:
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receiving a specified beam steering vector (BSV); determining a number of concentric sub-apertures based upon a beam spoiling vector associated with said BSV; dividing the total aperture into the determined number of concentric sub-apertures; computing a spoiled BSV for at least one of two orthogonal co-planar dimensions perpendicular to the direction of propagation of a transmit wavefront based on the BSV; applying the spoiled BSV in divergent directions for each sub-aperture by; for each element i in each of said sub-apertures, computing a beam steering phase coefficient, where said beam steering phase coefficient is determined by the equation - View Dependent Claims (2, 3, 4)
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5. An apparatus for beam forming in a phased array antenna having a total aperture, comprising:
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a communications processor configured to process INS data to determine a beam pointing vector and a beam spoiling vector; a beam spoiler operatively connected to said communications processor and configured to compute phase coefficients for each element in said total aperture based at least in part on said beam spoiling vector; a beam steering generator operative coupled to said beam spoiler and said phased array antenna elements and configured to steer said phased array antenna with at least said phase coefficients. - View Dependent Claims (6, 7)
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8. An apparatus for beamforming in a phased array antenna having a total aperture, comprising:
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means for receiving a specified beam steering vector (BSV); means for determining a number of concentric sub-apertures based upon a beam spoiling vector associated with said BSV; means for dividing the total aperture into the determined number of concentric sub-apertures; means for computing a spoiled BSV for at least one of two orthogonal co-planar dimensions perpendicular to the direction of propagation of a transmit wavefront based on the BSV; means for applying the spoiled BSV in divergent directions for each sub-aperture by; for each element i in each of said sub-apertures, computing a beam steering phase coefficient, where said beam steering phase coefficient is determined by the equation - View Dependent Claims (9, 10, 11)
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12. A computer-readable medium storing a non-transitory computer program executable by at least one computer, the computer program comprising computer instructions for in a phased array antenna having a total aperture:
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receiving a specified beam steering vector (BSV); determining a number of concentric sub-apertures based upon a beam spoiling vector associated with said BSV; dividing the total aperture into the determined number of concentric sub-apertures; computing a spoiled BSV for at least one of two orthogonal co-planar dimensions perpendicular to the direction of propagation of a transmit wavefront based on the BSV; applying the spoiled BSV in divergent directions for each sub-aperture by; for each element i in each of said sub-apertures, computing a beam steering phase coefficient, where said beam steering phase coefficient is determined by the equation - View Dependent Claims (13, 14, 15)
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Specification