Distributed Positioning Technique in Wireless Ad Hoc Sensor Networks

To support processing and collaboration, every node in the network needs to know the identity and location of its neighbors. This can be easily obtained in a planned network and quite hard in ad hoe networks whose topology is constructed and updated in real time. Selflocation using GPS may not be feasible but an effective distributed positioning algorithm is to be used. The proposed technique is a distributed infrastructure free positioning algorithm which achieves robustness through iterative propagation of information through a network. The two primary obstacles to positioning in an ad-hoc network like sparse anchor node problem and the range error problem are considered. In order to meet the above problems the new distributed algorithm is generated. This algorithm consists of two phases: start-up and refinement. For the start-up phase the Hop-TERRAIN algorithm is used to overcome the sparse anchor node problem, and refinement algorithm is used to refine the position estimates generated by Hop-TERRAIN. The experiment is carried out in a network containing 400 nodes randomly placed in a square area and the resulting error magnitudes are represented as percentages of each node’s radio range.