Research On Monitoring Technology Of Sensor Network For Heritage Site

With the advancement of cultural heritage protection in China,more and more new technologies for Internet of Things(Io T)are applied to the parameter monitoring in cultural heritage reserves,museums,etc..Accompanied by the development of Io T technology,monitoring solutions with low cost and simple have fundamentally changed the approaches for cultural heritage conservation.In addition,the devices with miniature size and low power consumption make it possible to build Wireless Sensor Network(WSN).Earth ruins,a kind of cultural heritage,refers to the architectural heritage with soil as the main raw material.The traditional monitoring methods for earthen sites are manual monitoring and wired sensor monitoring,while the solution of WSN technology was seldom applied for earthen site monitoring.Based on the earthen sites and environmental characteristics,this paper designed a general WSN monitoring system for earthen sites to meet the requirement of long distance and long-term deployment in the field.Firstly,this paper studies the communication technology and standards for architectural heritage(wood architectural heritage,brick architectural heritage,earthen architectural heritage,etc.),and discuss the superiority and weakness of various schemes.It is clear that the wide-area and low-power characteristics of LoRa technology are suitable for field earthen site monitoring.According to the characteristics and environmental conditions of earthen site,the main content and specific requirements of earthen site monitoring were analyzed to design a wireless network structure for meeting the application requirement of earthen site protection area.Then,the system adopts modular design,with Raspberry Pi development board as the processing core,LoRa module and wireless communication module as the wireless gateway of the communication module,and LoRa terminal and sensor device as the terminal sensing device.A Linux server was adopted to build a database and realize a set of monitoring system for earthen site.The hardware design includes gateway and terminal sensor.And that,the gateway device has rich external expansion interface,which has strong scalability and upgradability.In software,the gateway program was designed based on Raspberry Pi including data processing subroutine relied on Isolation Forest method,LoRa transceiver subroutine,and communication mechanism depended on TDMA and polling method.The network security protocol was developed,as well the packet format was defined from terminal to gateway to server and the related dates were stored in the database form.In addition,field communication tests were carried out on the system in Suoyang City site.Through collecting the RSSI,packet loss rate and other indicators between gateway and nodes,the main communication interference and possible interference in the earthen site environment were analyzed comprehensively,and the communication distance and range of the monitoring system were measured.After testing,the system meets the expected design requirements within the site of Suoyang City.