Analyzing target strength and echo-to-reverberation ratio of targets buried in sediment

The calculation of the scattering field from the buried targets, which is insonified by the acoustic wave with low grazing angle, is very important for designing a detection system. However, the scattering field from a buried target can not be obtained using the methods based on the ray model. Combining the wavenumber integral model and virtual source method, a software for 3D scattering field from the buried target was developed. Introducing the definition of effective target strength, the target strength and echo-to-reverberation ratio of buried conical frustum and spherical shell were computed. The effects of buried depth and incident grazing angle were analyzed. The results show that the echo-to-reverberation is always very low so that it is very difficult to detect with the monostatic mode. The simulation shows that if the bistatic detection mode is applied, the echo-to-reverberation ratio is improved above 40dB when the target is buried under 30cm below the bottom surface. The simulation results are useful for real application.