NeTS: Cognitive Networking of the Oceans: Localization and Tracking Fundamentals

海底无线通信和网络具有广泛的潜在科学，商业和军事应用，但由于水传播媒介的本质，仍然是一项艰巨的任务。海底通信成功的基础是强大的定位和跟踪，以支持位置感知数据路由和在无gps海洋环境中的自主导航。目前最先进的海底定位和跟踪方法考虑了昂贵的、高功率的惯性测量传感器、基于地球物理的成像和声学信号技术。然而，长传播延迟、水运动引起的多普勒效应以及海底环境的高动态多径特性，导致声学和成像测量中的显著误差和异常值。该项目旨在通过提供新的算法解决在存在潜在错误测量的情况下估计海底传播信号到达角度的问题，从而显著推进（精度提高5倍）3d被动海底声学定位技术的最新进展。然后，算法将嵌入到内部开发的可编程水声调制解调器中，形成一个用于评估和演示的实验性四节点网络。定位能力将在远程无线导航和监视的通信、指挥和控制应用场景中进行演示。该项目将整合所有大学学位水平的研究和教育，建立交叉列出的海底声学定位及其应用和活动的研究生/本科生课程，以接触到初中和高中学生群体。还将进行这一领域的技术转让活动。该项目旨在改变信号到达方向（DoA）估计在海底声学链路上的模式，偏离熟悉的l2范数子空间分解理论及其变体，并首次考虑l1范数信号子空间分解。由于l1范数衍生子空间对异常值和/或数据损坏的抵抗能力以及该领域最近的计算进展，该项目将采用新颖的l1范数最大投影主成分分析天线阵列测量，为海底声学网络设计一种新颖的、抗异常值多普勒和多路径的DoA估计方法。l1规范定位和跟踪将支持位置感知数据路由和自主导航应用，在没有gps的海洋中偶尔出现严重的动态信号散射和路径丢失。

Undersea wireless communications and networking has a wide range of potential scientific, commercial, and military applications, but is still a daunting task due to the very nature of the water propagation medium. Fundamental to the success of undersea communications is robust localization and tracking to support position-aware data routing and autonomous navigation in the GPS-less oceanic environment. Current state-of-the-art approaches for undersea localization and tracking consider expensive, power-intense inertial measurement sensors, geophysical-based imaging, and acoustic signaling techniques. However, long propagation delays, Doppler effects due to water movement, and the highly dynamic multipath nature of the undersea environment result in significant errors and outliers in acoustic and imaging measurements. This project aims to significantly advance (five-fold in precision) the state of the art in 3D-passive undersea acoustic localization by providing novel algorithmic solutions to the problem of estimating the angle of arrival of undersea propagating signals in the presence of potentially faulty measurements. The algorithms will then be embedded in in-house-developed programmable underwater acoustic modems to form an experimental four-node network for evaluation and demonstration. Localization capabilities will be demonstrated in communication, command and control application scenarios for remote wireless navigation and surveillance. The project will integrate research and education at all University-degree levels by establishing cross-listed graduate/undergraduate courses on undersea acoustic localization and its applications and activities to reach out to groups of middle and high-school students. Technology transfer activities in this field will be also pursued.The project pursues a paradigm shift in how signal Direction-of-Arrival (DoA) estimation is carried out over undersea acoustic links by deviating from the familiar L2-norm-subspace decomposition theory and its variants and considering, for the first time, L1-norm signal subspace decomposition. Motivated by the resistance of L1-norm-derived subspaces against outliers and/or data corruption and the recent computational advances in the field, this project will employ novel L1-norm maximum-projection principal-component analysis of the antenna array measurements to design a novel, outlier- Doppler- and multipath-resistant DoA estimation method for undersea acoustic networks. L1-norm localization and tracking will support position-aware data routing and autonomous navigation applications in the GPS-less oceans under occasional severe dynamic signal scattering and path loss.