Comparison of the radar clutter cancellation performance of post- and pre-Doppler STAP for ground moving target identification from an experimental airborne surveillance radar

Within this paper we report our study that compared the performance of pre-Doppler and post-Doppler STAP processing algorithms applied to the same radar trials data, collected by QinetiQ's Enhanced Surveillance Radar. The performance of these algorithms was quantified by clutter cancellation ratios and target signal improvement factors (the ratio of the signal to clutter plus noise ratios with and without STAP processing). We have shown that pre-Doppler and post-Doppler STAP may be tuned to give the same level of clutter cancellation. We present results in which bright target signatures are seen to affect the STAP processors and reduce the overall clutter cancellation. We have found that for our two phase center trials radar data, PRI staggered post-Doppler STAP gives greatly enhanced clutter cancellation compared to the simple fixed window post-Doppler STAP. The application of either moving window or auxiliary bin post-Doppler STAP was found to degrade the processor output. The importance of normalizing the final range Doppler map to prevent the amplification of thermal noise and remove the weight-norm variation as a function of Doppler is shown to be a critical step to allow interpretation and application of detection algorithms after STAP processing.