海底掩埋物体的目标强度与信混比分析

小掠射角声波照射下的掩埋物体散射声场计算,对水声探测系统的设计十分重要。现有基于声线理论的方法,无法计算小掠射角声波照射下的掩埋物体散射声场。基于波数积分声场模型和虚源方法,开发了可计算海底掩埋物体三维散射声场的模型软件。通过引入等效目标强度的定义,仿真计算了掩埋圆台和球壳的等效目标强度和回声信混比,并分析了掩埋深度和声波掠射角对信混比的影响。结果表明,用单基地方式工作时,掩埋物体的回声信混比总是很小,探测十分困难,若采用双基地探测,当掩埋深度达到30cm时,信混比可提高40dB以上,对掩埋物体探测系统的设计具有参考价值。

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.