Effects of clutter modeling in evaluating STAP processing for space-based radars

RLSTAP is shown to be an effective tool for modeling clutter representative of that seen by an actual spaceborne system. Realistic effects, like the Doppler aliasing of the angle-Doppler clutter spectrum from a high velocity platform and the non-homogeneity of site-specific clutter, can be modeled and their impact on adaptive signal processing studied. The example simulated in this work demonstrates that the Doppler aliasing of the clutter spectrum impacts the requirements on the STAP processor. The processor requires four spatial degrees of freedom to effectively suppress the clutter, while in previous cases with slower platforms only two were sufficient. This should be considered in designing a space-based radar system. Additionally, the non-homogeneity of the site-specific clutter influences STAP requirements. Care must be taken to keep the required sample support small and to choose the secondary data cells such that they are as close as possible, statistically, to the data from the test range cell.