The maximum ocean depth so far reported is about 11 000 m, and is located in the Mariana Trench in the Western Pacific Ocean. The hybrid unmanned underwater vehicle, Haidou, is developed to perform scientific survey at the deepest parts of the Earth oceans. For vehicles working at the full-ocean depth, acoustic positioning is the most effective and popular method. The 11 000 m class acoustic positioning system is relatively massive and complex, and it requires specialized research vessels equipped with compatible acoustic instruments. As a compact testbed platform, it is impractical for Haidou to carry an LBL/USBL beacon with its large volume and weight. During the descent to about 11 000 m, horizontal drift could not be eliminated because of the hydrodynamics and uncertain ocean currents in the sea trials. The maximum depth recorded by Haidou is 10 905 m, and determining the precise location of the deepest point is challenging. With the bathymetric map produced by a multibeam sonar, the terrain contour matching (TERCOM) method is adopted for terrain matching localization. TERCOM is stable in providing an accurate position because of its insensitivity to the initial position errors. The final matching results show the best estimate of location in the reference terrain map.

迄今为止，报告的最大海洋深度约为11000 m，位于西太平洋的马里亚纳海沟。混合动力无人水下航行器“海豆”被开发用于在地球海洋最深处进行科学勘测。对于在全洋深处工作的车辆，声学定位是最有效和最受欢迎的方法。11000 m级的声学定位系统相对庞大且复杂，需要配备兼容声学仪器的专门研究船。作为一个紧凑的测试平台，对于海斗来说，携带体积大，重量大的LBL / USBL信标是不切实际的。在下降到大约11000 m期间，由于水动力和海试中不确定的洋流，无法消除水平漂移。Haidou记录的最大深度为10 905 m，确定最深点的精确位置具有挑战性。对于多波束声纳产生的测深图，采用地形轮廓匹配（TERCOM）方法进行地形匹配定位。TERCOM对初始位置误差不敏感，因此在提供精确位置方面很稳定。最终匹配结果显示了参考地形图中最佳位置估计。