MMSE Beamforming With Quadratic Quiescent Pattern Constraints for Circular Array STAP

摘要

The goal of this project was to develop new and innovative processing methods for clutter and interference mitigation for Space-Time Adaptive Processing (STAP) with circular arrays. The focus was on developing a robust minimum mean square error (MMSE) beamforming technique using quadratic quiescent pattern constraints (MMSE-QPC) that works with arbitrary array configurations, including the circular UHF Electronically Scanned Array (UESA) and the standard linear array. The MMSE-QPC technique provides a general framework for quiescent and adaptive space-time beampattern synthesis which provides both main beam and sidelobe control with reasonable computational complexity. Beampattern control is achieved by imposing a set of inequality constraints on the weighted mean- square error between the adaptive pattern and a desired beampattern over a set of angle-Doppler regions. An iterative procedure for satisfying the constraints is developed which can be applied as post-processing to standard MMSE beamformers. The algorithm is used to synthesize a nearly uniform sidelobe level quiescent pattern for the UESA, and to control sidelobe levels for the same array in an adaptive manner. Performance results using data provided by Lincoln Lab show that under low sample support conditions, sidelobes can be effectively suppressed while maintaining high signal-to-interference plus noise ratio, and deep nulls on clutter and interferers.