Abstract: A lower-frequency compact radar system for wide-angle surveillance. Direction-finding receive antennas consisting of colocated orthogonal electric and magnetic dipoles provide target angles from the radar. The size of this antenna unit is reduced to the point where internal noise is comparable to external to achieve maximum compactness. High sensitivity is achieved with an efficient class of pulsed/gated, linearly swept-frequency waveforms that are generated and processed digitally. For backscatter radars, close to 50% duty factors are realized. The rules for waveform design and processing overcome problems of range/Doppler aliasing and/or blind zones. After mixing in the receiver, processing bandwidths are much less than RF signal bandwidths, so that simple, inexpensive personal computers are used for real-time signal processing. Digital FFT algorithms determine target range and Doppler, and DF algorithms determine its angles.
Type:
Grant
Filed:
February 28, 1992
Date of Patent:
November 1, 1994
Assignee:
Codar Ocean Sensors, Ltd.
Inventors:
Donald E. Barrick, Belinda J. Lipa, Peter M. Lilleboe, Jimmy Isaacson