Research On Wireless Sensor Network Localization Algorithm Based On RSSI Correction

With the development of science and technology, the wireless sensor network has been more widely used, especially in the field of traffic management, environmental monitoring, production safety, smart home as well as medical equipment, etc. and the node location was crucial for these applications, only clear the location of the sensor node, we could know that "where a specific event occurred ", and then made decisions and took measures, the monitoring data without location information was meaningless, such as: vehicle tracking, forest environment monitoring, coal mine accidents, search and rescue personnel, and so on. Therefore, a precise positioning technology had important significance for the application of wireless sensor networks.This paper first introduced some existing typical positioning algorithm in wireless sensor networks, and their advantages and disadvantages were simply analyzed. The existing WSN localization algorithm mainly was divided into range-based localization and range-free localization, based on whether to measure the actual distance between nodes in the process of locating. At present, the ranging method mainly included TOA(Time of Arrival)、TDOA (Time Difference of Arrive)、AOA(Angle of Arrival)、RSSI(Received Signal Strength Indicator) etc. Among them, RSSI converted the signal transmission losses in the air as the distance using theoretical or empirical model, so the RSSI ranging did not need to add any additional hardware, saving cost, simple,thus it was widely used, and became the hotspot of current research.This paper carried out the research from two aspects which were ranging and localization, aiming at the defects existing in weighted centroid localization algorithm based on the RSSI ranging, and combining the characteristics of wireless sensor networks.First of all, in the ranging stage, weighted centroid localization algorithm based on the RSSI ranging did not make full use of the information between beacon nodes to correct the distance between beacon node and unknown node, so RSSI ranging value had a great error. Secondly, In the stage of weight selection, the algorithm did not reflect the influence of different beacon nodes on unknown node.Aiming at these defects, a weighted centroid localization algorithm based on RSSI correction was proposed.In ranging stage,the new algorithm corrected RSSI ranging value,by taking the distance and the signal strength information between beacon nodes into account at the same time,It made full use of the known information in the network environment;In the stage of weight selection,the new algorithm fully considered the influence of the beacon node on unknown node by using a new method, the simulation results showed that the improved algorithm has significantly improved the positioning accuracy.However,some deficiencies were found in the new algorithm in later studies, so a modified algorithm based on RSSI correction was proposed. The simulation results showed that the modified algorithm has effectively improved the positioning accuracy and reduced the positioning errors.