Broadband incoherent virtual array beamforming on small-scale array for passive detection

It cannot be guaranteed that array spacing corresponding to half-wavelength of each frequency when broadband signals are processed by passive detection scheme. Therefore, for high-frequency, side lobe will rise when array spacing is half the wavelength of the low-frequency. In addition, the main lode of small-scale array will be wider due to limited array aperture. In order to resolve these two disadvantages for passive detection of small-scale array, virtual array beamforming based on time-delay information is studied in this paper. But this technology often requires high sampling frequency which will increase computational complexity. In order to use virtual array beamforming to processing broadband signals at lower sampling frequency, broadband incoherent virtual array technology based on phase information is introduced in this paper. The effectiveness of these two methods is shown by simulation and sea experiment.