浅海环境下动态水声传感器网络节点定位关键技术研究

The key technology of localization for mobile underwater acoustic sensor networks (UASN) in shallow ocean is studied in this project. By building a channel scene of underwater localization in shallow ocean, this project studies the influence of localization parameters affected by sea surface or sea bottom, time-varying multipath transmission, noise and Doppler frequency induced by free movement of node and water wave movement. A channel transmission model applied to dynamic UASN is got. The localization error of dynamic node in complicated multipath transmission environment and its joint probability distribution model are studied. The Cramer-Rao Bound (CRB) of localization estimation is deducted. For acquiring high accurate 2-dimension angles of target node, the time-frequency properties of Chirp signal in shallow ocean is analyzed, the effective marine creature signal suppression method and the extraction strategy of line of sight path are proposed. The convex optimization idea is brought in this project, and nonlinear and non-convex localization problem based on angle parameter is conducted by convex relaxation. 3-dimension localization algorithm theory for distributed dynamic UASN based on the convex optimization is proposed. Combined with channel scene, performance analysis and simulation verification are conducted. In all, this project will be efficiently reduce the influence of dynamic node localization affected by harsh environment and marine creature’s irregular movement, and make contribution to the accurate estimation of the dynamic node location in complicated shallow ocean.

本课题旨在研究浅海环境下动态水声传感器网络(UASN)节点三维位置坐标获取关键技术。构建浅海环境下定位信道场景，研究由于复杂水声环境而形成的海面（底）反向散射、时变多径传输、噪声及由节点自由移动和水波运动而产生的多普勒频移对定位参数的影响，得到适用于动态水声传感器网络的信道传输模型。研究复杂多径传输下动态节点定位误差及其联合概率分布模型，推导定位估计的克拉美罗界。分析Chirp信号在浅海环境下的时频特性，据此提出有效的海洋生物干扰信号抑制方法和视距路径提取策略，以获取高精度的目标节点二维角度参数信息。引入凸优化思想，将基于角度参数的非线性非凸定位问题进行凸松弛，提出基于凸优化的分布式动态UASN节点三维定位算法理论，并同建立的信道场景相结合，进行性能分析及仿真验证。总之，本课题将有效降低恶劣水声环境及海洋生物不规则运动对动态节点位置信息的影响，为复杂浅海水域中动态节点位置的精确估计做出贡献

本课题研究了浅海环境下动态水声传感器网络(UASN)节点三维位置坐标获取关键技术。构建浅海环境下定位信道场景，研究由于复杂水声环境而形成的海面（底）反向散射、时变多径传输、噪声及由水波运动产生的节点移动对定位参数的影响，得到适用于动态水声传感器网络的信道传输模型。研究复杂多径传输下动态节点定位误差及其联合概率分布模型，推导定位估计的克拉美罗界。分析Chirp信号在浅海环境下的时频特性，据此提出有效的海洋生物干扰信号抑制方法和视距路径提取策略，以获取高精度的目标节点二维角度参数信息。引入凸优化思想，将基于角度参数的非线性非凸定位问题进行凸松弛，提出基于凸优化的分布式动态UASN节点三维定位算法理论，并同建立的信道场景相结合，进行性能分析及仿真验证。同时，为了节约大规模UASN的部署成本，有效提高节点的通信效率，设计了高效的功率放大器。总之，本课题有效降低了恶劣水声环境对动态节点位置信息的影响，为复杂浅海水域中动态节点位置的精确估计做出贡献。