Location discovery for sensor networks with short range beacons

A challenging problem in sensor network research is location discovery. In this paper, we present TPSS, a time-based positioning scheme for sensor networks with short-range beacons1. By measuring Time Difference of Arrival (TDoA) of signals from those nearby beacons, nodes can use TPSS, according to the range differences, to effectively estimate their locations through trilateration. After a sensor gets localized, it can act as a beacon and use its computed position to help others on location discovery. This iterative procedure helps to resolve more sensors with unknown positions. We also propose iTPSS as an enhancement to improve the localization accuracy by means of a clustering-based position re nement. Features of TPSS and iTPSS include high scalability in network size, low communication overhead, no requirement for time synchronization, etc. Extensive simulations have been conducted and the results indicate that both schemes are effective and ef cient for location discovery in sensor networks with short range beacons, and iTPSS outperforms TPSS in positioning accuracy.