A modified Conjugate Gradient algorithm for low sample support in STAP radar

The Conjugate Gradient (CG) has been shown recently to be equivalent to the MultiStage Wiener Filter (MSWF) [1] which is an effective tool for interference suppression in space-time adaptive processing radar. In this paper, we give further insight on the interconnection between the MSWF and the CG. We propose a modified version of the CG for low sample support where we use the forward/backward (f/b) averaging for estimating the covariance estimation. The new algorithm takes benefits of the CG for rank compression and of the (f/b) subaperture smoothing for sample support compression [2]. The effectiveness of the algorithm is demonstrated through simulations.