Joint Direction Of Arrival Estimation Of Subarrays Based On Near-Field Nulling Weight

As for long-range target Direction of Arrival (DoA) estimation with benthonic long linear arrays under near-field acoustic interference and space non-stationary noise, a novel joint DoA estimation of subarrays algorithm is proposed, which is based on near-field nulling weight. The long linear array is divided into several high overlap subarrays. The near-field nulling weight is calculated for subarrays to eliminate the effect of the near-field interference on target detection. The spatial frequency variance weighted joint DoA method is presented based on the little discrepancy of the subarrays' DoA estimates to repress the space nonuniform noise and detect the target in a long distance. The maximum value of spatial spectrum is random in the frequencies without the target because of the space non-stationary noise. The simulation results show that compared with long-linear-array conventional beamforming, long-linear-array conventional beamforming based on near-field nulling weight and long-linear-array multiple signal classification based on near-field nulling weight method, this proposed technique can effectively reduce the background level of spatial spectrum (over 60 dB), improve signal to noise ratio (above 15 dB) and has high spatial resolution, with better engineering application value.