Real Time Deformation Monitoring System Based On WSN And GNSS-RTK Design And Implementation

Due to the influence of various factors,Collapse events always happen when building’s position and shape change drastically.In nature,the factors such as heavy rainfall often bring soil deformation movement that causes geological disasters such as mudslides and landslides.However,traditional deformation monitoring methods like leveling network and corner network contain the problems of long monitoring cycle,low precision and high cost.In order to realize omni-directional and all-weather real-time deformation monitoring,this paper independently designs and develops a set of deformation real-time monitoring system based on multi-source WSN(Wireless Sensor Networks)and GNSS-RTK(Global Navigation Satellite system real time kinematic).Firstly,the monitoring station is built by the technologies of energy acquisition,power management,environmental information acquisition and high-precision displacement data acquisition;Then the multi-source heterogeneous data of the monitoring station will be upload to the data processing center through Lo Ra / 4G wireless communication;Finally,the system will parse and process the multi-source heterogeneous data,and store the high-precision positioning coordinates and sensor data in the database.The deformation risk assessment is realized with the multi-source data fusion algorithm,and the visual display is realized that based on GIS technology.The main research ideas and contents are as follows:(1)Hardware design of monitoring station.Independent design and development the monitoring station energy acquisition and power management system,GNSS-RTK board circuit,single chip microcomputer and peripheral interface circuit,and integrated various sensors and wireless modules.Through the design,development,welding and testing of the hardware of the monitoring station,and the iteration of the hardware version,finally,the operation of each functional module is stable,so as to realize the self-sufficiency of the power supply of the monitoring station and the wireless acquisition of various sensor data.(2)Software designThe monitoring station can reach centimeter level of RTK Positioning Data,environmental sensor data acquisition and wireless transmission.The single chip microcomputer of the monitoring station completes the data collection of meteorological sensors such as wind speed and rainfall,soil humidity geological sensors,gyroscope and accelerometer attitude sensors,and realizes the wireless communication and networking that based on Lo Ra and MQTT technology.The multi-source visual monitoring system of the data center realizes the functions of data parse,storage,analysis and display.Deformation hazard assessment is carried out by fusing GNSS displacement data with sensor data for analysis.The visualization platform superimposes that based on map,displays multi-source heterogeneous data,and realizes historical data query and curve drawing.(3)System performance test and practical applicationThis paper tests each module and the overall performance of the system.Including these tests of outdoor energy acquisition,sensor data acquisition,wireless communication packet loss rate,Lora communication and other specific functions.The test results show that the efficiency of the energy acquisition circuit is about 87%,and the data acquisition performance of the sensor is stable.When the communication distance between the gateway and the Lo Ra terminal is within 4000 m,there is no packet loss phenomenon.When the distance increases to more than 5000 m,the packet loss rate increases rapidly.Through the simulation experiment of deformation,the experimental results show that the height measurement error is less than 5mm.Field deployment of GNSS-RTK monitoring sites using high-rise building,infrastructure and slope monitoring as application cases.In the aspect of building deformation monitoring,the inclination angle of the building is measured by gyroscope and accelerometer.In terms of land disaster monitoring,the main research object is slope monitoring,and the GNSS-RTK monitoring station is installed on the slope of the park,and the local disaster body is monitored by combining rainfall and soil moisture sensors.At present,the system has operated stably for half a year,and there is no fault during operation.