Target Localization of Short Vertical Line Array Based on Least Squares Method

In the shallow sea environment, array of small array elements may not be able to accurately locate targets due to undersampling. To address this issue, the paper proposed a method called sound field extension based on the reception of array of small array elements, which generates a virtual measurement field of a vertical array with lager number. The method utilizes the extended acoustic field for VTRM. This approach significantly improves the focusing and positioning performance of the TRM. The key implementation lies in estimating the normal wave mode coefficients from the acoustic field acquired by the short vertical line array. The paper uses the least squares method to estimate the mode coefficients. Experimental results demonstrate that compared to conventional time processing methods for an array of small array elements, the VTRM method using the a vertical array with a large number of elements can effectively enhance targeting and focusing performance of the short array. For array of small array elements with 21 elements, the SNR (Signal Interference to Noise Ratio) effectively improves by 4.32 dB.