R & D Associates

Robert L Kirkwood

Archie Gold

Steven L West

Certain man-made structures located in a complex background, such as railroad ties, telephone poles, and fences are detected by a flying craft, using a low powered structure resonant radar system. The radar system transmits a radar signal which includes wavelengths of the same order of magnitude as twice the spacing of the elements of the man-made structure or grating multiples thereof, and transmits them in a plurality of different directions and frequencies. Reflections of the transmitted radar are received and structural resonance backscatter is detected wherein the backscatter amplitude at the resonant frequency is much higher than that at adjacent frequencies or that of the clutter background, indicating the presence of the search-for type of structure. The bright structural resonance backscatter can then be exploted by the structure resonant radar for guidance, homing, etc.

Structure resonant radar detection apparatus and method

A circuit is described which receives enemy radar signals in the form of encoded bursts or pulses, and which immediately generates and transmits, in sequence, a large number of target denial signals which are similar to the received signal. The transmitted signal masks signals from friendly craft, and deceives the enemy by providing rational false targets for him to engage. The carrier frequency of the enemy or threat, signal is detected, and is used to select one of a group of local oscillation signals which are superheterodyned with the received signal to produce an IF (intermediate frequency) signal which is recirculated and and superheterodyned with the local oscillator frequency to produce a series of signals for transmission that are similar to the received signal. The amplitude and offset doppler of each of the target denial signals are individually controlled prior to retransmission to maximize performance. In the recirculation loop, the circulated signal is hard limited, or clipped, and is also low limited, and also passed through a contoured bandpass to avoid the build up of noise.

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Pacific Palisades, CA, United States of America

Robert L Kirkwood