High-resolution angle-Doppler imaging by sparse recovery of underwater acoustic signals

The low resolution of Fourier 2-D spatial temporal spectrum estimation and the insufficient sample size of sonar space-time sampling data often caused difficulties in high-resolution space-time spectrum estimation. Aiming to solve this problem, we proposed a high-resolution angle-Doppler imaging method and designed an anti-reverberation space-time filter based on the sparse recovery of underwater acoustic signals. The proposed imaging method established the spatio-temporal sparse representation model of array signal under the condition of few observation samples of single measurement vector, and reconstructed the high-resolution angle-Doppler image of echo and reverberation through the matching pursuit algorithm and base pursuit algorithm. By utilizing the space-time distribution characteristics of echo and reverberation and the prior information of sonar rangecell under test, a reverberation dictionary composed of special space-time guidance vectors was designed, and was used to reconstruct the reverberation and formed an anti-reverberation space-time filter to suppress the reverberation interference of angle-Doppler plane. Computer simulations indicated that, under two conditions of forward and side-view array of moving sonar, the single measurement vector of sonar array was successfully used in the reverberation background to reconstruct the high-resolution angle-Doppler profile of low-speed moving target multi-spot echo. Its frequency resolution had a better performance than the Fourier resolution and the angle resolution broke through the Rayleigh limit of the array, the resolution was obviously superior to the Fourier space-time spectrum estimation. © 2021 Acta Acustica.