EAGER: Wireless Underground Sensor Network for In-Situ Monitoring of Soil Parameters, Soil-Structure Interaction Behavior, and Buried Utiltiies

这一早期概念探索性研究补助金项目的研究目标是采用新的跨学科视角，因为它旨在研究无线电传播和性能，以及通过典型土壤介质的吸收损失的特征，以便于使用现有的芯片收发机可靠地估计允许的地下网络结构。将无线传感器网络扩展到地下应用具有极大的变革性，因为它解决了许多紧迫的社会挑战，如地下基础设施的状况监测、改进的矿山安全、精准农业和隐蔽的边境保护。虽然有限范围的实地研究已经证明了使用地面传感器微尘进行地下数据通信的可行性，但实际的解决方案，如功率放大、网状网联网和电流能量收集，还有待研究。这项研究调查了无线传感器网络中主要使用的低于1 GHz的芯片收发器的介电测量得出的吸收损耗估计。该研究旨在为简化路径损耗估计提供不确定界，并基于实验观测提出经验修正，以便于可靠地设计井下无线传感器网络拓扑和网络协议。除了土壤参数外，还考察了载波频率、调制格式、传输功率和数据速率等无线电传输因素对地下信号传播的影响。该项目的成果可以产生一种监测各种地质结构现象的强大和低成本的解决办法，从而提高地下取样的空间密度，并最大限度地减少侵入性。改进土壤-水介质的介电吸收分类可能有助于改进基于阻抗的、非核的先进土壤密度测定方法，并有助于基于射频的地下成像技术。该项目的成功执行将有助于利用UWSN来解决国家对监测和维护地下基础设施的关切。该项目还在教育和研究中培养了更广泛的多学科科学和技术意识。

The research objective of this EArly-Concept Grants for Exploratory Research (EAGER) project is to engage novel interdisciplinary perspectives as it aims to study radio propagation and performance coupled with characterization of absorption losses through representative soil mediums to facilitate reliable estimation of permissible underground network structures using currently available chip transceivers. The extension of wireless sensor networks to underground applications has the potential to be highly transformative as it addresses numerous pressing societal challenges, such as condition monitoring of buried infrastructure, improved mine safety, precision agriculture, and covert border protection. While field studies of limited scope have demonstrated the feasibility of underground data communications using terrestrial sensor motes, practical solutions such as power amplification, mesh networking, and galvanic energy harvesting have yet to be investigated. This research investigates absorption loss estimates derived from dielectric measurements specific to sub-1GHz chip transceivers used predominantly in wireless sensor networks. The research aims to provide uncertainty bounds for simplified path loss estimates and to propose empirical corrections based on experimental observations to facilitate reliable design of underground wireless sensor network topologies and network protocols. In addition to soil parameters, radio transmission factors including carrier frequency, modulation format, transmission power, and data rate are examined for influence on underground signal propagation. Outcomes of this project could yield a powerful and low-cost solution to monitoring a variety of geo-structural phenomena thereby improving spatial density of subsurface sampling and minimizing intrusiveness. Improved classification of dielectric absorption through soil-water mediums may contribute to improvement of advanced impedance-based, non-nuclear methods for soil density determination as well as aid in RF-based subsurface imaging techniques. The successful execution of this project would facilitate the use of UWSNs to address national concerns associated with monitoring and maintenance of buried infrastructure. The project also develops a broader awareness of multi-disciplinary science and technology in education and research.