Space-Time-Frequency Adaptive Processor Design for Ultra-Sparse Apertures

This paper addresses the problem of designing an adaptive processor to cancel multiple interference sources using an ultra-sparse, very large array of distributed sensors. Specifically, we will address the case where the array has sufficient dispersive properties such that sufficient degrees-of-freedom required by a standard "dense tap" space-time adaptive processor to cover the delay spread of all the potential interference sources would result in an infeasible solution. We propose a "sparse tap" architecture, where we derive the minimum dimensionality of a STAP processor required to cancel a given interference environment. We then look at the case were the interference sources may have non-zero velocity, and derive an extension of the processor to cover this environment.