ABCUnloc: Acoustic Backscatter Communication-based Underwater Localization

随着海洋工业和水下物联网的不断发展，自主水下航行器（auv）有望得到越来越广泛的应用，在恶劣的海洋环境中执行各种任务。AUV的自主操作依赖于准确确定其路线上的位置，但GPS在水下不起作用。AUV导航通常由水声定位系统支持，例如长基线（LBL）系统。然而，LBL节点的电池需要定期更换，因此操作要求高，成本高，对海洋环境构成很大威胁。工业和科学界迫切需要生态友好、低成本和低维护的水下定位系统来支持AUV导航。利用水声反向散射通信（UABC），节点可以通过反射入射声信号以接近零的功率进行通信，该行动将开发一种新型的基于声学反向散射通信的水下定位（ABCUnloc）系统，该系统在已知位置部署三个或更多个多节点水下浮标，以向AUV反向散射定位信息。该行动的R&I目标是：(1)模拟水下浮标和水下航行器之间的UABC通道。(2)设计一种新型的多节点水下浮标（每个节点由压电阵列和超低功耗控制电路组成），并评估其用于基于uabc的水下航行器定位的可行性。(3)设计基于uabc的三维定位算法，支持水下动态环境下的AUV导航。(4)优化ABCUnloc系统（即每个水下浮标的节点数量和节点间距离，覆盖水下区域的浮标数量和位置），优化AUV定位功耗、精度、鲁棒性和对海洋环境的影响。(5)在可控波浪储罐和北海对ABCUnloc系统进行原型和测试。

As offshore industries and the Internet of underwater things continue to expand, autonomous underwater vehicles (AUVs) are expected to be in increasingly widespread use, carrying out various tasks in harsh marine environments. The autonomous operation of an AUV relies on accurately ascertaining its position along its route, but GPS does not work underwater. AUV navigation is typically supported by underwater acoustic positioning systems, e.g., long baseline (LBL) systems. However, batteries of LBL nodes need to be replaced periodically, thereby being operationally demanding and costly and posing a great threat to the marine environment. Eco friendly, low-cost and low-maintenance underwater localization systems are urgently needed by industry and scientific communities to support AUV navigation. Leveraging underwater acoustic backscatter communication (UABC) that allows a node to communicate at near-zero power by reflecting incident acoustic signals, this action will develop a novel acoustic backscatter communication-based underwater localization (ABCUnloc) system that deploys three or more multi-node subsurface buoys at known locations to backscatter localisation information to an AUV. The R&I objectives of the action are: (1) To model the UABC channel between a subsurface buoy and an AUV. (2) To design a novel multi-node subsurface buoy (each node comprising a piezoelectric array and ultra-low-power control circuits) and assess its feasibility for UABC-based AUV localization. (3) To devise UABC-based 3D localization algorithms that can support AUV navigation in dynamic underwater environments. (4) To optimise the ABCUnloc system (i.e. the number of nodes and inter-node distance per subsurface buoy, the number and placement of buoys for covering an underwater region) regarding AUV localization power consumption, accuracy and robustness and impact on marine environment. (5) To prototype and test the ABCUnloc system in controllable wave tanks and in the North Sea.