A Waveform Independent Approach to Detecting Targets in Clutter with Coherent Nonidentical Pulses

This paper presents novel signal processing that enables detection of targets in clutter with waveforms that may change pulse-to-pulse. The waveform changes are unconstrained as long as they are coherent. Nonidentical pulse (NP) processing, a component of waveform diversity, has been the subject of much research due to its potentially transformative impact on technologies such as radar-embedded communications, electronic protection, MIMO radar, multi-mission radar and many others. It is well known that standard processing (i.e., matched filtering followed by moving target detector (MTD)) is not suitable for NP processing due to the loss of clutter coherence caused by Range Sidelobe Modulation (RSM). Much of the research in this area has focused on reducing the range sidelobe levels compared to the mainlobe so that the effect of RSM is less deleterious, or constructing unique filters for each pulse which result in nearly identical sidelobe behavior (thus restoring coherence). In a companion paper, the Neyman-Pearson optimum detector (OD) for range-migrating targets in the presence of clutter is derived. The current work asserts that the framework presented in the companion paper is also capable of optimally processing nonidentical pulses. A simulation of the optimum detector with nonidentical pulses (ODNP) is explored and its performance is compared with that of both standard processing with nonidentical pulses (SPNP) and the optimum detector with identical pulses (ODIP). As expected the ODNP dramatically outperforms the SPNP. Also, the performance of the OD when clutter parameters are not perfectly known is examined. It is found that the OD experiences only marginal losses due to clutter parameter estimation errors of nontrivial magnitude. Furthermore, it is shown that as the size of the processing window increases, the ODNP performance approaches that of IP processing, becoming effectively waveform independent when the interference is dominated by clutter.