An efficient range-free multi-hop localisation algorithm for irregular wireless sensor networks

In the range-free multi-hop localisation algorithm, the physical distance between nodes is estimated based on hops, and complex ranging equipment is not required during this process. This could help realise simpler system configuration, while lowering the node cost and consumption of energy in wireless sensor networks. During the actual deployment of nodes, the deviation of the final estimated location from the actual location is generally caused by factors such as shielding or barriers during the hop distance conversion. In this paper, an improved method for range-free multi-hop localisation is proposed which could improve the precision without increasing the cost and reducing the performance of the algorithm. First, we obtain the optimal weighting function for location estimation according to the error between the estimated locations of non-beacon nodes and their actual locations. Then, we correct the inaccurate estimated locations of non-beacon nodes through geometric constraints. Lastly, we demonstrate via simulation that our proposed localisation method outperforms the basic range-free multi-hop algorithms as well as their improved methods in irregular wireless sensor networks.