A radar system includes an image forming circuit that provides a two-dimensional image of an operating environment. The image includes pixel elements representative of the operating environment. The system includes at least one filter configured to convert the two-dimensional image into a clutter classification map of clutter regions. A predetermined number of clutter regions are selected as training cells for a predetermined cell-under-test (CUT). A space-time adaptive processor (STAP) is configured to derive a weighted filter from training cell data. The STAP applies the weighted filter to a digital return signal associated with the predetermined CUT to provide a STAP-filtered digital return signal having the clutter signal components substantially eliminated therefrom.