DOA estimation for long-distance underwater acoustic sources based on signal self-nulling

Abstract

The direction-of-arrival (DOA) estimation for the long-distance underwater acoustic sources usually suffers from low levels of signal-to-noise ratio (SNR) and insufficient snapshot data. Therefore, a novel signal self-nulling based DOA estimation algorithm is proposed. First, assume that the angular sector, where the desired signal is located, is known. Then, the beampattern of the minimum variance distortionless response beamformer in this angular sector is circularly mapped onto a unit circle. Finally, the pseudo spatial spectrum is constructed by integrating the circular mapping beampattern over the whole circle. Computer simulations show that the proposed DOA estimation algorithm can produce a sharper spectrum peak around the true DOA and therefore, achieve better DOA estimation precision with low levels of SNRs and small snapshot numbers. The underwater experiment also demonstrates the superiority of the proposed DOA estimation algorithm over other existing methods for the long-distance underwater acoustic sources.