Research on Indoor Mobile Node Localization Based on Wireless Sensor Networks

The positioning technology, as one of the key technologies of wireless sensor network, can make each node acquire its own position information in the network to achieve target monitoring, data acquisition and behavior prediction. Under indoor environment, owing to the influence of obstacles, signal transmission between mobile nodes generally is under the non-line-of-sight environment, causing more localization errors. In this paper, focused research on the localization algorithm in the initial state and mobile state when nodes enter the network is conducted under non-line-of-sight environment. Firstly, a multi-signal-based localization algorithm is proposed against the initial localization stage at which mobile unknown enters the network. Appropriate anchor nodes are selected to participate in localization computing through the signal strength value, thereby narrowing the area where unknown nodes locate and improving the localization accuracy of nodes. Meanwhile, aiming at the problem of non-line-of-sight errors, anchor nodes with low errors are selected by introducing non-line-of-sight inhibitory factor to reduce the impact of non-line-of-sight measured value on the localization results. Secondly, aiming at the motion state of mobile nodes, a localization algorithm based on historical localization is proposed. Mobile nodes are located according to the number of anchor nodes around node localization moment in conjunction with the historical localization information of nodes. Meanwhile, the coordinate computing method is modified by introducing a modification value to make the coordinate values of nodes closer to the real value. The simulation result indicates that the proposed localization method can improve the localization accuracy effectively and has good adaptability.