RELAX based estimation of signal and clutter echoes modeled as discrete point scatterers

We consider the radar signal return to be originating from discrete point scatterers, and utilize this to estimate clutter echoes and calibrate a multi-channel array. The point scatterers are parameterized with a specific Doppler and spatial frequency (u and v direction). Previous work considering this formulation of clutter is the SCHISM approach. Their estimation is based on the radar version of CLEAN. For many cases where the scatterers are well separated, the CLEAN algorithm is fast and accurate. However, for closely spaced scatterers (in either Doppler or space), the CLEAN method suffers. Thus, to enhance the ability to resolve such scatterers we instead employ a new estimator (RESCUE) that uses the approach introduced in RELAX. As for SCHISM, range gates are processed individually and independently from each other and sample covariance matrices are avoided. Real world multi-channel data are used to demonstrate the proposed method. The results are very promising and indicate that this approach can indeed be used as an alternative to traditional STAP.