Three dimensional radar antenna method and apparatus
First Claim
1. A method of implementing a three dimensional ground based bistatic radar receiving antenna for detecting and precisely determining locations of birds in a surveillance volume, said method comprising:
- providing a vertically oriented offset parabolic cylindrical antenna;
implementing said offset parabolic cylindrical antenna as receive only;
mounting an array of antenna elements along the vertical focal line of said offset parabolic cylindrical antenna;
receiving and converting signals from said antenna elements to digital data; and
combining said digital data in a three dimensional ground based bistatic radar external to said three dimensional ground based bistatic radar receiving antenna to form multiple simultaneous receiving beams of any desired elevation beamwidths and sidelobes and electronically scanned in elevation by controlling the progressive phase difference and amplitude between said digital data from said array of antenna elements along said vertical focal line of said offset parabolic cylindrical antenna.
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Abstract
A ground based avian radar receive antenna is implemented using a vertically oriented offset parabolic cylindrical antenna. The desired azimuth beamwidth is determined by the width of the parabolic cylinder reflector surface and the desired elevation beamwidth by the height of the parabolic cylinder reflector surface. A vertical array of antenna elements is mounted along the vertical focal line to provide electronic scanning in elevation. Low sidelobe levels are obtained using tapered antenna element illumination. Low cost modular construction with high reflector accuracy is obtained by attaching a thin metal reflector to thin ribs machined or stamped in the shape of the parabolic cylinder reflector surface. The antenna is enclosed in a radome and mechanically rotated 360 degrees in azimuth.
108 Citations
19 Claims
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1. A method of implementing a three dimensional ground based bistatic radar receiving antenna for detecting and precisely determining locations of birds in a surveillance volume, said method comprising:
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providing a vertically oriented offset parabolic cylindrical antenna; implementing said offset parabolic cylindrical antenna as receive only; mounting an array of antenna elements along the vertical focal line of said offset parabolic cylindrical antenna; receiving and converting signals from said antenna elements to digital data; and combining said digital data in a three dimensional ground based bistatic radar external to said three dimensional ground based bistatic radar receiving antenna to form multiple simultaneous receiving beams of any desired elevation beamwidths and sidelobes and electronically scanned in elevation by controlling the progressive phase difference and amplitude between said digital data from said array of antenna elements along said vertical focal line of said offset parabolic cylindrical antenna. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A three dimensional ground based bistatic radar receiving antenna for detecting and precisely determining locations of birds in a surveillance volume, said antenna comprising:
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a vertically oriented offset parabolic cylinder reflector surface; an array of antenna elements mounted along the vertical focal line of said offset parabolic cylindrical reflector surface; receivers coupled to said antenna elements, said receivers configured to receive, downconvert, and digitize signals from said antenna elements; and data multiplexers coupled to said receivers and configured to send said antenna elements digital signal data to a three dimensional ground based bistatic radar external to said three dimensional ground based bistatic radar receiving antenna where said digital signal data is combined to form multiple simultaneous receiving beams of any desired elevation beamwidths and sidelobes and electronically scanned in elevation by controlling the progressive phase difference and amplitude between said digital signal data of said antenna elements. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A method of implementing a three dimensional ground based bistatic radar receiver antenna, said method comprising:
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providing a short vertical offset parabolic cylindrical reflector surface; mounting an antenna element at the focal point of said short vertical offset parabolic cylindrical reflector surface; receiving and converting said antenna element signal to digital data; vertically stacking multiple said short vertical offset parabolic cylindrical reflector surface sections to form a tall offset parabolic cylindrical antenna; and combining said digital data from said tall offset parabolic cylindrical antenna in a three dimensional ground based bistatic radar external to said three dimensional ground based bistatic radar receiver antenna to form multiple simultaneous receiving beams of any desired elevation beamwidths and sidelobes and electronically scanned in elevation by controlling the progressive phase difference and amplitude between said digital data from said tall offset parabolic cylindrical antenna. - View Dependent Claims (19)
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Specification