United Technologies Corporation

Marshall Greenspan

Kevin W Lindell

Francis X McGroary

Stephen Adelman

A multi-pulse pulse compression radar system transmits two or more radar pulses having different frequency components having a time delay therebetween. A signal conditioning stage time and phase aligns the received signals and provides a composite radar signal having time and phase continuity throughout.

Multi-pulse pulse compression radar system

In a digital moving target indicator (MTI) employing digital filters for rejecting low frequency clutter signals having magnitudes which are 20 to 60 db greater than the moving target return signal, the dynamic range and resolution accuracy requirement of an analog-to-digital (A/D) converter, used to convert the return radar analog video signal to a plurality of digital signal equivalents for presentation to the digital filters, is reduced from that normally required by prefiltering the return video signal through a prefilter network. The digital prefilter utilizes: a low resolution accuracy (low order bit capacity) analog-to-digital (A/D) converter to convert the return analog video signal (comprising both low frequency clutter and high frequency moving target component signals) to a digital signal, a low-pass digital filter to pass only the low frequency clutter signal, a digital-to-analog converter to reconvert the digital clutter signal to an analog clutter signal which is substantially equivalent to the clutter component signal value of the analog video signal, and a summing circuit which provides an analog sum signal representative of the amplitude difference between the analog clutter signal and the return analog video signal, to provide a video signal with a greatly enhanced moving target to clutter signal ratio. The sum signal is presented to the system A/D converter, permitting the use of a low resolution system A/D converter having a substantially reduced dynamic range and lower cost, the system A/D converter providing the digital equivalent signal of the enhanced return video for further processing in the digital MTI filters.

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Fairfield, CT, United States of America

Marshall Greenspan