Difference Coarray Design based on Genetic Algorithm and Convex Optimization

Large hydrophone array is an effective device for receiving acoustic signals in the ocean. In order to reduce engineering costs while meeting the needs of performance, a sparse array design method is proposed in this paper. This method combines genetic algorithm and convex optimization weighting to design a special sparse array named Difference Coarray (DC). In the design process, peak side-lobe level (PSLL) and degrees of freedom (DOF) is used as the objective function of genetic algorithm to design DC. Then convex optimization weighting is performed to reduce the sidelobes of the array obtained in the first step. By analyzing the beam patterns of the DC with element position uncertainty, it can be seen that the design array with convex optimization weighting maintains low side-lobe level while narrow main lobe, which demonstrates that DC has strong anti-interference ability. In addition, the beam pattern performance of the DC, coprime array and nested array is compared to prove the advantages in PSLL. The results prove that DC has lower PSLL under the same main lobe, which is beneficial to weak target detection.