时间反转和逆时偏移混合法中参数改变对目标检测和定位的影响

Effects of parameters of acoustic field to detection and location of targets using TR-RTM mixed method

时间反转和逆时偏移混合法能有效地抑制分层介质中界面或底面反射波的干扰,从而实现分层介质中目标的检测和定位。该文计算得到阵列阵元的疏密,目标在空间中不同位置,以及不同载波频率相应的声场图和声场等高线图,从而详细研究不同参数对目标检测和定位的影响。研究结果表明,接收阵元需要达到一定数目才能获得较好的聚焦效果;目标无论距阵列远近都可以被很好地定位,特别是离界面很近的目标也可以清晰地分辨出来;用调制载波信号可以得到在目标处更尖锐的声场分布,但周围的各处声场分布高低起伏,可能带来定位的不稳定。

A mixed method of reversed time migration and time reversal can suppress the disturbance of the interface reflected waves or the bottom reflected waves in the layered medium, hence, the detection and position of the target in the layered medium can be realized effectively. In this paper, we study the density of array elements, the different positions of the target in space, and different carrier frequencies on the impact of target detection and positioning. The results show that the receiving array elements need to reach a certain number to get a good focusing effect. The target can be well located both near and far from the array, especially the objects close to the interface can also be clearly distinguished. The ac carrier signal sharper acoustic field distribution at the target can be obtained, but the fluctuation of the acoustic field distribution around the surroundings may cause positioning instability.