Clutter mitigation for space based radar by appropriate choices of array aspect ratio and radar PRF

Different from the airborne scenario, space time adaptive processing (STAP) for space based radar (SBR) is a full system design task whose performance is significantly determined by radar system parameters such as array aspect ratio and PRF. To mitigate clutter, the two parameters should be appropriately designed. The suppression of mainbeam clutter is discussed while taking the earth's rotation and high range foldovers into consideration. Clutter rank is derived by modeling it as an equivalent two-dimensional spatially band-limited process and it is shown to be a function of array aspect ratio and radar PRF. Relationships between clutter rank and the two parameters are analyzed. Optimal array aspect ratio and radar PRF are obtained by minimizing clutter rank with the tradeoff of minimum discernable velocity (MDV). A high fidelity modeling of SBR is given to illustrate the effectiveness of the method.