Resolution of direction of arrival and number of signal(s) in a highly noisy environment
Jeffrey Y. Beyon, Stelios C. A. Thomopoulos · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1998
The majority of Direction-of-Arrival (DOA) estimation methods studied in the literature work effectively in relatively strong signal power environment [positive dB of Array- Signal-to-Noise-Ratio (ASNR)]. In weak power signal environments, conventional beamformer-based and subspace-based methods fail to estimate the DOA correctly. The MaxMax method allows to maintain accurate estimates of the DOA even in extremely noisy environments (-10 dB of ASNR). The method is reviewed and its performance is compared with that of the Conventional Beamformer, Capon's Beamformer, MUSIC, ESPRIT, and Min-Norm methods. In contrast with the subspace-based methods which entirely depend on the full rank signal covariance matrix, the MaxMax method does not. Hence, the performance of the method remains superior to that of the others without adjusting the algorithm to the characteristics of source signals such as multipath or singlepath. If the signal power is so weak that its presence is almost negligible, Akaike's Information Criterion (AIC) or Minimum Description Length (MDL) do not yield correct estimates the number of signal paths. A new 'spatial sampling' technique and its performance are presented for estimating the number of signals in case of strongly suppressed signal power.