%0 Journal Article %T Cooperative Anchor-Free Position Estimation for Hierarchical Wireless Sensor Networks %A Chih-Yu Wen %A Yu-Cheng Hsiao %A Fu-Kai Chan %J Sensors %D 2010 %I MDPI AG %R 10.3390/s100201176 %X This paper proposes a distributed algorithm for establishing connectivity and location estimation in cluster-based wireless sensor networks. The algorithm exploits the information flow while coping with distributed signal processing and the requirements of network scalability. Once the estimation procedure and communication protocol are performed, sensor clusters can be merged to establish a single global coordinate system without GPS sensors using only distance information. In order to adjust the sensor positions, the refinement schemes and cooperative fusion approaches are applied to reduce the estimation error and improve the measurement accuracy. This paper outlines the technical foundations of the localization techniques and presents the tradeoffs in algorithm design. The feasibility of the proposed schemes is shown to be effective under certain assumptions and the analysis is supported by simulation and numerical studies. %K anchor-free localization %K cooperative estimation fusion %K wireless sensor networks %U http://www.mdpi.com/1424-8220/10/2/1176