TDOA localization algorithm with compensation of clock offset for wireless sensor networks

This paper presents a source localization algorithm based on the source signal's time-difference-of-arrival (TDOA) for asynchronous wireless sensor network. To obtain synchronization among anchors, all anchors broadcast signals periodically, the clock offsets and skews of anchor pairs can be estimated using broadcasting signal's time-of-arrivals (TOA) at anchors. A kalman filter is adopted to improve the accuracy of clock offsets and track the clock drifts due to random fluctuations. Once the source transmits signal, the TOAs at anchors are stamped respectively and source's TDOA error due to clock offset and skew of anchor pair can be mitigated by a compensation operation. Based on a Gaussian noise model, maximum likelihood estimation (MLE) for the source position is obtained. Performance issues are addressed by evaluating the Cramér-Rao lower bound and the selection of broadcasting period. The proposed algorithm is simple and effective, which has close performance with synchronous TDOA algorithm.