Research On WiFi Indoor Positioning Technology And Its Application In Monitoring Radioactive Sources

With the rapid development and wide application of nuclear technology,the regulation of radioactive sources has become an important task to ensure public safety and protect the environment.However,due to the loss,theft or illegal transfer of radioactive sources,too many radioactive incidents have occurred,which have caused serious harm to the environment and human health.Therefore,the design and establishment of a radioactive source monitoring system is an important measure to ensure public safety and environmental protection.Through real-time and accurate acquisition of radioactive source locations and radiation dose values,the monitoring system can provide early warning and take necessary measures to minimize the risk of accidents and potential hazards,and contribute to ensuring the sustainable development of society and the safe application of nuclear technology.First,this paper introduces the application scheme of wireless positioning technology in the remote monitoring system of radioactive sources.When the radioactive source is in an open outdoor area,the Bei Dou satellite navigation system(BDS)with mature technology and high accuracy and developed by China is used to obtain its location information;however,when the radioactive source is in an indoor area,the penetration of the satellite signal to the external wall of the building is limited,and the satellite navigation system cannot provide positioning service indoors.To address this problem,this system uses WiFi network-based indoor positioning technology,which has the advantages of low cost,easy deployment,and wide signal coverage,and is suitable for the positioning needs of indoor locations.However,due to the problem of large positioning error caused by the time-varying volatility of WiFi indoor received signal strength,an improved location fingerprinting positioning method is proposed to improve the positioning accuracy of indoor radioactive sources in complex environments.Second,a radioactive source remote monitoring system is designed and developed by combining network communication,embedded development,sensing detection and database technologies using the proposed wireless positioning technology and algorithms.The monitoring terminal in this system can obtain the dose value of the radioactive source as well as the surrounding temperature,humidity and geographic location information in real time,and send these data packaged to the remote monitoring center using the TCP/IP protocol of GPRS network.The monitoring center software can simultaneously process the monitoring terminal data of multiple radioactive sources installed in different locations,and process,store and visualize the real-time monitoring data of radioactive sources.Managers can use the system equipment to realize remote real-time monitoring of radioactive sources.Finally,the actual function test of the designed radioactive source remote monitoring system shows that the proposed improved indoor fingerprint positioning algorithm has a positioning accuracy within 2～3 meters in the system application,while the outdoor positioning accuracy based on Beidou is 5～10 meters,which meets the requirements of radioactive source positioning accuracy.The average relative error between the system’s environmental dose monitoring value of radioactive sources and the standard tool detection value is 6.12%.The software function and database of the monitoring center run normally and stably,and the remote monitoring system of radioactive sources meets the requirements of effectiveness,convenience and practicality for monitoring radioactive sources.