Novel sensor location scheme using time-of-arrival estimates

This study proposes a novel scheme for locating an asynchronous sensor with synchronised beacons using time-of-arrival (TOA) estimates. In this scheme, a reference beacon initiates the localisation by emitting a ranging signal, and the sensor position is estimated by measuring the length of the signal propagation path from the reference beacon to every beacon via the sensor. The associated Cramér-Rao bound (CRB) is derived, and a localisation algorithm, which does not need a priori knowledge about the TOA estimation accuracy, is proposed based on the constrained least square (LS) principle. It is illustrated by numerical experiments that the proposed scheme features a lower CRB compared to the conventional time-difference-of-arrival (TDOA)-based scheme, and the performance of the proposed algorithm is close to the CRB, especially when the sensor is in the centre area surrounded by the beacons.