A Spatial Power Spectrum Estimator for Distributed Signals
Read, W. J. · Defense Technical Information Center (DTIC) · 2000
This report details the development of an N-channel spatial power spectrum estimation technique called the SPatial Incoherent Region Estimator (SPIRE). It was developed in support of research aimed at characterizing the spatial spreading of HF signals caused by the high latitude propagation environment with the ultimate goal of improving high latitude HF radio direction finding performance. Based on the assumption of temporal and spatial incoherence, SPIRE uses a surprisingly simple, yet effective, approach based on maximum likelihood principles to model the spatial power spectrum. The result is an algorithm which provides a more accurate and more informative characterization of the spatial nature of incoming signals than currently popular conventional and modern superresolution algorithms. This characterization includes bearing, spatial extent and power distribution, and total power of the signal. It also includes total noise power and modeling accuracy. The performance and utility of the SPIRE algorithm is demonstrated using both simulation and off-air data.