In this paper, the authors consider the problem of localization in wireless sensor networks and propose a distributed algorithm that helps unknown nodes to determine confident position estimates. The proposed algorithm is robust to range measurement inaccuracies and can be tailored to varying environmental conditions. The proposed position estimation algorithm considers the errors and inaccuracies usually found in signal strength measurements. They also evaluate and validate the algorithm with an experimental test bed. The test bed results indicate that the actual position of nodes are well bounded by the position estimates obtained despite ranging inaccuracies.