Research On Localization Technology For The Wireless Sensor Networks

The wireless sensor network(WSN) involves many technologies, such as the sensor, embedded technology, distributed information processing, communications, and micro-electromechanical technology. The WSN has been widely used in fields such as military affairs, medical treatment, transportation, and environment protection. In operations such as disaster relief and mine exploration, the node position in the network is of great significance. Therefore, obtaining the node location is a key issue for the WSN. This thesis studies localization algorithms in the WSN. Firstly, this thesis introduces the basic positioning principle, localization algorithm classification, commonly-used localization algorithms, evaluation index for localization algorithms, and problems that need to be solved. To improve the positioning accuracy of the traditional DV-Hop algorithm, this thesis analyses the error source of the DV-Hop algorithm and proposes an improved DV-Hop algorithm. The algorithm is improved in four aspects. The simulation results show that compared with other similar algorithms, the proposed algorithm significantly improves the positioning accuracy and stability.Secondly, this thesis studies localization in the three-dimensional space and proposes a dimensional algorithm based on the improved DCP(Degree of CoPlanarity). The concept of coplanarity is added into the traditional DV-Distance algorithm to reduce the positioning error caused by anchor nodes which are coplanar. Unknown nodes which have been located are developed into assistant anchor nodes to improve the proportion of anchor nodes. The simulation results show compared with other similar algorithms, the proposed algorithm can improve the positioning accuracy and coverage.Finally, this thesis further studies the localization technology in the mobile WSN. An Adaptive Monte-Carlo-based mobile localization algorithm is proposed. The numbers of samples and hops are set according to the actual situation to reduce the sampling frequency and amount of calculation. Experiments show that the proposed algorithm features higher positioning accuracy with lower communications costs. The proposed algorithm is suitable for irregular and range-free mobile WSN and will play a role in real application.