An Algorithm of Grating Lobe Suppression Based on Virtual Array Element Interpolation

Synthetic aperture sonar has the characteristics of high resolution imaging which is not limited by the detection range. It can be used for imaging and mapping of the seafloor. However, the product value of detection range and speed of navigation is limited by the physical length of the array in the traditional synthetic aperture sonar. When the speed of navigation is improved on condition that the detection range is not reduced, the grating lobes which reduce the imaging quality will be produced. In this paper, a virtual array transformation technique that realizes the interpolation of sparse aperture is proposed. This algorithm can eliminate the main lobe interference from the grating lobes; mitigate the contradiction between the detection distance and the navigation speed. The sweep efficiency of active synthetic aperture sonar is improved without affecting the basic quality of the image. At the end of the paper, the feasibility of the algorithm is verified by simulation.