Localization for Anchoritic Sensor Networks

We introduce a class of anchoritic sensor networks, where communications between sensor nodes is undesirable or infeasible, due to, e.g., harsh environment, energy constraints, or security considerations. Instead, we assume that the sensors buffer the measurements of the physical phenomena over the lifetime, and report measurements directly to a sink (note that “report” does not necessarily require direct communication). Upon retrieval of the reports, all sensor data measurements will be available to a central entity for post processing. Our algorithm is based on the further assumption that some of the data fields that are being observed by the sensors can be modeled as a local (i.e. having decaying spatial correlations) stochastic process; if not, then choose another auxiliary field, such as hydroacoustic noise, cloud shadows cast on the ground, or animal heat. The sensor nodes record the measurements, or a function of the measurements, e.g., “1” when the measured signal is above a threshold, or “0” otherwise. These sensors generated time-stamped sequences are ultimately transferred to the sink. The localization problem is then approached by analyzing the correlations between these sequences at pairs of nodes. As engineering ramifications to the idea of anchoritic sensors, we discuss the localization scheme for sensors deployed on the seabed, where radio signals are strongly attenuated in sea water within feet of their transmission; also, we discuss a two-tiered architecture tasked with combining heterogenous nodes: deaf sensors and local masters.