Comparison of Interpolation Methods in Synthetic Aperture Sonar Based on R-D Method

The movement of the array in Synthetic aperture sonar(SAS) relative to the object causes range migration in echo space,which would affect the ultimate image and is mainly corrected by interpolation at present.Based on range-Doppler algorithm,this paper first discusses the cause and correction idea of range migration,gives several classic interpolation methods,then presents their detailed expressions used in SAS,followed by a comparison of their performance.Finally,the simulation of point targets is carried out,target images before and after correction are displayed,added with some comparison of imaging quality and computation load.It is demonstrated that all these methods can improve the image quality,but Lagrange method and Shannon method show an advantage in mending the azimuth direction,which can be used in practice.