Radar-waveform design for detecting targets in clutter

The waveform dependence of matched-filter systems is investigated for detecting signals in nonstationary clutter, including the range dependence of the clutter power return. As is normally the case for microwave radars with moderate waveform durations, it is assumed that the r.m.s. clutter Doppler-shift spread is less than the signal Doppler-shift resolution. General expressions are derived for the output S/C ratio, as a function of the radar ambiguity function, the target range delay and the Doppler shift, and specific examples are evaluated. It is shown, for example, that, owing to the nonstationarity of the clutter return, long waveforms which resolve the mean Doppler-shift difference between target and clutter may result in a worse S/C ratio than that achieved with a short waveform which has no Doppler-shift resolution.