Wireless sensor networks nodes localization based on inter-node RF range measurement using Vernier effect

Various method of inter-node range measurement has been used in wireless sensor networks (WSNs) for node range-based localization. Radio frequency (RF) based time-of-flight system promised an accurate result. However, it is only effective for long distance uses instead of it deploy high cost hardware time synchronization, therefore, it is not so feasible to be implemented in WSNs. To challenge the difficulties and reduce the cost of using RF for short ranges measurement, a simpler hardware based range measurement technique rely on Vernier effect has been proposed. Three experimental nodes have been fabricated to realize the method. Preliminary test of inter-node range measurement show a fairly accurate relation between inter-node range of distance and output sensing pattern. Further, a simple localization using the real experimental data shows the feasibility of using this method for real WSNs cases.