Simulating elastic targets for sonar algorithm development

Targets interrogated during synthetic aperture sonar (SAS) applications may exhibit elastic scattering behavior and reradiate sound after the initial geometric returns. The current suite of reconstruction techniques fails to fully capture elastic mechanisms, causing “late-time” energy to appear out-of-focus and away from the target location. A model capable of simulating late-time energy from elastic targets will be important in exploring the tradespace of advanced reconstruction methods that properly capture late-time energy. Stanton’s 1988 model presents the scattering amplitude of an elastic cylinder as a function of frequency and spherical angles. This presentation uses Stanton’s scattering model to simulate the time series of pressure scattered by the cylinder for SAS collection geometries. This approach allows the target scattering model to be readily coupled with time series models for the environment to generate high fidelity simulated data. This paper will explore this modeling approach as a substitute for field data during initial stages of algorithm development for improved target localization. It will show that the modeled data has the expected characteristics through comparison to a target strength reference and by reconstructing the modeled returns to form images. Finally, applications for this method will be discussed.