Research On Positioning Algorithms In Wireless Rechargeable Sensor Networks

With the rapid development and wide application of wireless sensor networks,the demand for time and stability of sensor networks is becoming higher and higher.The wireless charging technology has attracted wide attention,and researchers have begun to supply energy to sensor networks through the wireless energy transmission.This new sensor network is called Wireless Recharge Sensor Networks(WRSN).In WRSN,many applications generally require the location information of sensor nodes.On this basis,it can provide users with the desired monitoring information and services.If the network only provides node monitoring data and does not determine the location information of the node,it is meaningless in many applications.In addition,the location of nodes in WRSN also determines the charging planning and efficiency.Therefore,the location information of nodes is crucial.How to achieve the accurate node localization at low cost has become a research hotspot.In view of the existing problems of WRSN localization technology,this paper mainly studies the location problem of randomly deploying rechargeable sensor nodes in an area,and designs location algorithms based on the node charging time by using the self-localization wireless charger.This method does not require additional precision equipment,and has high positioning precision.This paper is divided into two parts:1.When the charger and nodes use omnidirectional antennas in WRSN,the transmission formula of electromagnetic wave under ideal conditions is combined with the formula of capacitor charging,and is corrected according to the actual environment,so the environment adaptation charging model of nodes based on the omnidirectional charging antenna is obtained.The relationship between the charging time and the charging distance can be described through the node charging model.An accurate location equation is established,and the method of solving the node location is designed.The location equation of the omnidirectional charging antenna is relatively simple.The solution matrix of the node location is obtained by the least square method,and the location algorithm based on Time Difference of Charge(TDOC)is implemented.2.When the charger uses the directional antenna and nodes use omnidirectional antennas in WRSN,the transmission formula of electromagnetic wave under ideal conditions is combined with the formula of capacitor charging,and is corrected according to the actual environment,so the environment adaptation charging model of nodes based on the directional charging antenna is obtained.The relationship between the charging time and the charging distance in different directions can be described through the node charging model.An accurate location equation is established,and the method of solving the node location is designed.The location equation of the directional charging antenna is relatively complicated.The objective function of node location is obtained by combining the geometric method with the least square method.Then,the improved particle swarm optimization algorithm is applied to solve the node location,and the location algorithm based on Time of Directional Charge(TODC)is implemented.