Abstract: An improved location discovery algorithm upon previous Hop-terrain localization algorithm was proposed in this paper. At first, the algorithm used distance vector exchange to get hop counts from sensors to anchors and estimate he initial positions of sensor nodes. Then it iteratively updated the sensor nodes' positions by utilizing the initial posilion estimates and information of immediate neighbors of sensors. A fin}grained distance control mechanism was introduced in the position iteration update phase to decrease the position error. I}he distance control mechanism chose the possible position with great accuracy as iteration result based on the constraints of the distance to those neighbors with high weight value calculated by our algorithm. Simulation results show that the fraction of located nodes is increased and the position error is decreased compared with Hop-terrain algorithm.

Key words: Wireless sensor networks, Localization, Distance controlled