A hybrid iterative localization algorithm in wireless sensor networks

Localization is one of the imperative issues in wireless sensor networks. The classical range-free and range-based localization algorithms have respective pros and cons, which cannot gracefully meet the practical requirements, such as the heterogeneity of network and irregular distribution. Thus, the high-accuracy localization algorithm HILS (Hybrid Iterative Least Square) is proposed in this paper, utilizing nodes with and without calibration capability. The "hybrid" characteristic of HILS holds in two aspects: being able to take advantage of both the range-based information and range-free information, e.g. connectivity and shortest path, and to calculate the initial coarse locations using a certain lightweight algorithm (e.g. DV-Hop) to utilize the error-controllable localization algorithm in heterogeneous networks. Simulation results show that compared with classical range-free algorithm, the proposed algorithm can mitigate the local minima problem in the general iterative algorithms. Although its time consumption is related to the parameter of desired accuracy, it can be reduced by exchanging little amount of information between nodes to rank the order to localize, and by using the optional initial estimation with a certain lightweight range-free algorithm. Experimental analysis represents that HILS is a practical, stable and effective localization algorithm.