Research On WSN Indoor Location Method Based On Fingerprint Matching

The innovation of wireless sensor network technology plays an important role in the life and production of human beings.As an important branch of wireless sensor networks,localization technology is the focus of scholars' research domestic and overseas.As GPS and other outdoor positioning methods have bad connection in the in indoor environment,it is difficult to locate effectively in complex indoor environment,so the study of finding reliable indoor positioning methods has great significance.Range-based localization is mainly measured by the signal intensity which transmitted by the base station nodes indoors,and the coordinates of ordinary nodes can be calculated by multiple points distance measurement.However,there are many interferences in this method,the signal transmitted by base station exist multipath phenomena such as reflection and refraction,so ranging by signal intensity is not accurate.Moreover,the cost of base station nodes is huge,and it is difficult to deploy the location system widely.Rang-free localization is represented by fingerprint location method.Firstly,it establishes the feature fingerprint map of the location scene,and then matches the fingerprint map.This method can reach accurate localization without base station nodes deployment or just deploy a small number of base station nodes,and the cost is minimal.The established location area fingerprint will not change for a long time,so it has higher reliability.Combined with the present situation of domestic and international researches,this paper presents a WSN indoor positioning method based on fingerprint matching;the method can be divided into three steps:First,build the signal strength fingerprint map in the positioning area;second,match the fingerprint map location;third,optimize positioning results.In step one,the Kriging interpolation algorithm is used to build a high-resolution location fingerprint map;in step two,the cosine similarity and spatial index are used to get the target location;In step three,the K-means is used to improve positioning accuracy.Based on the method,we develop the WSN positioning system,the Micaz is used as the base station node,the system experiment and simulation results show that the positioning method has better anti-jamming,also the positioning error in the indoor positioning scene is about 5 cm.