Unbiased Bearing Estimation in Low SNR Condition with an Acoustic Vector Sensor

Bearing estimation using cross-spectral method for an acoustic vector sensor, is unbiased and effective in high signal-to-noise ratio(SNR) environment. As SNR reducing, the mathematical expectation of estimates will deviate from the true azimuth, which means that the average of bearings measured by multiple times is no longer consistent with the direction of the target, it's unexpected and unfavorable in practical application. This paper analyses the influencing factor causing bearing biased in low SNR condition by cross-spectral estimation, proposes a new unbiased estimation method, gives the theoretical derivation process, and verifies the validity of this method by the computer simulation and actual data analysis.