Distributed RF Sensing Using Software-Defined Radios

A coarsely-synchronized, easy to deploy, distributed RF sensor network using embedded USRP software-defined radios on a dedicated IP network was developed and tested. The goal was the evaluation of a simple network and signal observation synchronization strategy on measured physical signals for use with collaborative sensor spectral estimation algorithms. The hardware and software architecture of the sensor network was developed, and coarse time synchronization was achieved between all sensors. The characteristics of the sensor network were measured, including relative time delays. Techniques that achieve finer estimates of parameters affecting sensor synchronization were examined, particularly the Cross-Ambiguity Function (CAF) and its relation to initial coarse time synchronization, and a sample application of spectral estimation is presented.