Zero Cross-Correlation Complementary Radar Waveform Signal Processor for Ambiguous Range Radars.
Patent, Filed 30 Jan 91, patented 10 Sep 91,
DEPARTMENT OF THE NAVY WASHINGTON DC
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A method and apparatus exploiting the discovery that the crosscorrelation of constantly spaced rows of the matrices representing certain pulse codes sum to zero. In a ranging system, such as a radar, pulses are coded according to the rows of a such a matrix, transmitted sequentially and each return processed sequentially through a filter matched to one of the coded pulses. A different preselected filter is used for each return. The sequence of filters is chosen so that for returns for a give range interval, each filter is matched to the representing auto-correlations of the returned pulses. These outputs are time delayed added coherently to form the compressed pulse, and annunciated as a target hit. Should the filters and returns be mismatched, as with ambiguous stationary clutter returns, the outputs of the filters are cross-correlations which, according to said discovery, sum to zero. thus the invention operates to remove ambiguous range clutter from returns in such a ranging system.
- Active and Passive Radar Detection and Equipment