Filters that mitigate waveform modulation of radar clutter

Abstract

Moving target indication (MTI) radars will require modified signal processing to be able to employ pulse-to-pulse agile waveforms. The main problem with conventional processing is that matched-filter pulse compression leads to range-sidelobe modulation (RSM) of clutter. Due to the fact that range sidelobes differ on each pulse, clutter energy that leaks into these sidelobes cannot be cancelled by subsequent processing. This study derives a figure-of-merit for pulse-compression filters that quantifies the signal-to-interference-plus-noise ratio (SINR) loss that results from RSM. Optimising this figure-of-merit results in sets of filters that mitigate RSM by producing matched sidelobes. The proposed filters are compared to low-sidelobe mismatch filters designed separately for each pulse. Simulation results indicate that an MTI radar could achieve a 5–10 dB improvement in SINR by using the proposed filters instead of low-sidelobe filters.