ABCUnloc: Acoustic Backscatter Communication-based Underwater Localization

随着海上工业和水下物联网的不断发展，预计自主水下航行器（AUV）将得到越来越广泛的使用，在恶劣的海洋环境中执行各种任务。AUV的自主操作依赖于沿其路线沿着精确确定其位置，但GPS在水下不工作。AUV导航通常由水下声学定位系统支持，例如，长基线（LBL）系统。然而，LBL节点的电池需要定期更换，因此操作要求高且成本高，并对海洋环境构成极大威胁。工业界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。利用水下声学反向散射通信（UABC），允许一个节点通过反射入射声信号以接近零的功率进行通信，这一行动将开发一种新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，将定位信息反向散射到AUV。研究与试验的目标是：（1）建立水下浮标与AUV之间的UABC信道模型。(2)设计一种新型多节点水下浮标（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AUV定位的可行性。(3)设计基于UABC的水下机器人三维定位算法，以支持水下机器人在动态环境中的导航。(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），包括AUV定位功耗，准确性和鲁棒性以及对海洋环境的影响。(5)在可控波浪水槽和北海中对ABCUnloc系统进行原型设计和测试。

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.