Asynchronous Self-Localization of Sensor Networks with Large Clock Drift

Large clock offsets and drifts impose many difficulties on sensor self-localization. We have proposed a differential time-difference-of-arrival (dTDOA) localization method in [1] to overcome the problem caused by asynchronous clock offsets. In this paper, the dTDOA method is extended to combat clock drifts by a two-stage clock-drift cancellation method. Furthermore, based on the clock-drift cancellation, a maximum likelihood estimation (MLE) method that is theoretically optimal for sensor locations is derived. The method can achieve sensor localization using a single round of time-of-arrival (TOA) measurements, and thus greatly reduces the communications burden and timing constraint.