Localization Technology Of Integrated Air-ground Wireless Sensor Network

The military sensor networks can acquire the information of battlefield situation effectively,which is an important part of information warfare in the recent years.And the location information of the sensors is also an indispensable content.On the one hand,the sensor end-devices may be deployed in a harsh environment and unattended area,which leads to difficult energy supply,so the terminals cannot be targeted by installing a GPS module.On the other hand,for the base station construction in this environment is little or not,it is difficult to obtain signals through the cellular network.For these reasons,to position these sensor nodes,either low power consumption or localization accuracy should be taken into consideration.To solve all the above problems,the paper studies the node localization of low-power wide-area sensor networks:Firstly,it introduces the background and significance of the research,then summarizes and analyzes the development status of related localization technologies,including the development of Low Power Wide Area Network(LPWAN)technology,algorithm based on the arrival time difference and the passive localization technology based on Unmanned Aerial Vehicles(UAVs).Then,the basics of the LPWAN network are introduced,including two main LPWAN technologies: LoRa and NB-IoT.Considering the terminal deployment cost,technical implementation difficulty and localization accuracy,this paper chooses LoRa and its LoRaWAN protocol for localization,studies the common TDOA-based localization analysis algorithm.After analyzing them,we make a conclusion that Chan's algorithm could obtain more accurate localization result.Furthermore,localization algorithm based on TDOA in 3D space is studied.By extending the classical Chan algorithm in 3D,dimensional iterative algorithm based on Fang algorithm is proposed,which reduces the positional information required to solve the equation,and doesn't increase the computational complexity.The simulation suggests that both algorithms can obtain the solution with the required accuracy.The localization effect of the Chan algorithm is better than the dimension reduction iterative algorithm,but the dimension reduction iterative algorithm requires less parameter information and can reduce the number of UAVs,which play the role of gateways.Finally,it is studied about two aircraft passiveTDOA-FDOA joint localization method.The Kalman filter can significantly improve the localization effect on the sensor nodes.The work of the paper revolves around the localization algorithm of the end-devices of the sensor network through the UAVs.Based on the low-power sensing network LoRaWAN,the three-dimensional localization algorithm is researched and compared,including the localization algorithm based on the TDOA and the TDOA-FDOA joint localization.