Accuracy Analysis of Point Target Reference Spectrum

The point target reference spectrum (PTRS) plays an important role in the imagery of multireceiver synthetic aperture sonar (SAS) system. Since the two-way slant range is characterized by the double square rooted terms, it is difficult to obtain the point of stationary phase by using the method of stationary phase. In order to solve this issue, approximations are often exploited. In this paper, the double square rooted terms is transformed into a single square rooted term based on the equivalent transformation of radical expression. With this operation, the point of stationary phase can be easily calculated based on the method of stationary phase. Consequently, the imaging algorithms can be developed by using presented PTRS. In this paper, we first show the range error introduced by this approximation. Then presented PTRS is applied to focus the targets, and the result based on back projection algorithm is used to demonstrate the efficiency of presented PTRS.