RSSI-based Proportional Difference Correction Location Algorithm For Underground Wireless Sensor Networks

The location of person under the mine is the core part of the mine safety.In recent years,Wireless sensor network technology which is a new type of information sensing,processing and interactive technology,will bring rapid development and progress of underground safety monitoring system.The core problem of the underground safety monitoring system is the location of the underground nodes,the information acquisition of the underground safety system is not lost.Node localization technology is the most basic and core partin wireless sensor networks.In the special environment of coal mine,the traditional GPS positioning method can not meet the requirements of the underground environment.At present,the main underground positioning system uses radio frequency identification,which is in close to the RF node that can be detected.Then get the location information.But the positioning mode of RFID is a kind of passive monitoring mode,which can not achieve the real-time location of underground personnel feedback.Aiming at underground safety supervision system which cannot afford to solve real-time positioning,and performance of instability problems.Combined with the positioning status of the wireless sensor networks,wireless sensor network knowledge and underground environment,this paper puts forward two kinds of model of underground wireless sensor networks node localization method,and simulated the two methods.In this paper,based on the multilateral localization algorithm of RSSI,the relationship between anchor nodes to obtain the proportional difference coefficient,the coefficient of the distance between nodes are used in the measurement by RSSI method.The RSSI measurement method needs different propagation models in different environments,and the RSSI ranging method is far better than the distance target because of its own limitation,that is to say,the accuracy of the RSSI to the distance is close to the target.The target of unknown node first reads the beacon nodes within the communication range of the broadcast information,RSSI intensity,by Calman filtering of RSSI signal to remove the noise in the signal,remove the noise value of the received signal strength can obtain more precise distance value,and then use the anchor node that is closest to the destination node and the anchor node construction the differential model,access to the system error,the target node location to remove system error,get more accurate distance value;and then use the proportional difference method to modified RSSI distance,through the simulation experiment,the positioning accuracy is better than the traditional RSSI positioning algorithm.As the original weighted centroid localization is not precise enough,the improved weighted centroid method is used to locate the nodes in the underground tunnel.This paper analyzes the problems existing in the distribution of the nodes in the tunnel environment,and puts forward some solutions.On this basis,we further adopt the method of proportional difference to get the distance correction,and further optimize the weighting factor,so that the positioning accuracy of the node is closer to the real effect.