Without prior knowledge of medium parameters, a method is proposed to detect and locate a target in layered media. Experiments were carried out for liquid/liquid and solid/liquid layered media, and the location of a target in them was obtained using three methods combined, i.e., the least-square method, the method of finding minimum dispersal degree of target distribution, and the snapshot time reversal and reverse time migration mixed method. The medium parameters, i.e., the acoustic velocities of upper and lower media as well as the thickness of the upper medium, were inversed simultaneously. The results show that the position of target is consistent with its actual position. Thus, the detection and location of a target in layered media are achieved without prior knowledge of medium parameters, and it overcomes the difficulty that the common time reversal method only detects the target, but cannot locate it.

中文翻译：

---

无需事先了解媒体参数，即可在分层媒体中检测和定位目标

在没有媒体参数的先验知识的情况下，提出了一种在分层媒体中检测和定位目标的方法。对液/液和固/液层状介质进行了实验，使用最小二乘法，求靶分布的最小散布度的方法和最小二乘法相结合的三种方法获得了靶的位置。快照时间反转和时间反转迁移混合方法。同时反转介质参数，即上，下介质的声速以及上介质的厚度。结果表明，目标位置与实际位置一致。因此，无需事先了解媒体参数即可实现目标在分层媒体中的检测和定位，