A powerful range-Doppler clutter rejection strategy for navigational radars

The authors describe a method to combat arbitrary delay-Doppler clutter. The problem is approached using the signal ambiguity function. A matched filter receiver is assumed and transmitted signal parameters are optimized to achieve the clutter rejection capability. The signal set chosen is the family of frequency-coded constant-amplitude pulse bursts, and a criterion function is derived in terms of the frequencies of individual subpulses. The proposed method optimizes the detection performance of the radar for any given clutter distribution in the delay-Doppler plane of the radar. Representative results are presented which show the ambiguity function for optimum FSK (frequency-shift-keying) bursts for different burst lengths and clutter distributions. The results obtained clearly bring out the effectiveness of the method