Research On Subgrade Settlement Monitoring System Of Railway Based On Spread Spectrum Technology

The safe,reliable and high-quality operation of the railway depends on the good smoothness of the railway subgrade.With the rapid development of China's railway industry and the dramatic increase in the scope of railway operations and operations,the settlement of railway subgrade has become one of the major hidden dangers threatening the safe operation of railways.The railway subgrade is in an outdoor working environment,where not only the lines are long,but some of them are still in the mountains and tunnels.Therefore,the signals are attenuated during the transmission.The traditional manual monitoring and wired monitoring need to consume huge manpower and material resources,and the general wireless transmission methods can not adapt to the working environment of the railway roadbed.In order to solve this problem,this paper designed a railway subgrade settlement monitoring system based on spread spectrum technology.The main contents are as follows:On the hardware platform of the system,by analyzing the relevant regulations and technical requirements for the monitoring of the settlement of railway subgrade in China,a high-precision JS series static level was selected as the monitoring instrument to collect the subgrade settlement information.The hardware platform of the wireless node of the system was analyzed and designed.Through the comparison of power consumption,anti-jamming performance and transmission distance,the wireless transceiver chose SX1278.The controller selects the STM32L151CBT6 A which can meet the resource requirements and has low power consumption advantages.According to the system requirements,the wireless module peripheral circuit is designed accordingly.In terms of system software design,in order to transmit data between wireless nodes more stable,energy-efficient and efficient,Contiki and Rime protocol stacks for wireless sensor networks were introduced.It mainly completed the porting of the Contiki and Rime protocol stacks to the IAR environment,modified the incompatible parts of the system,designed the hardware drivers,and configured the network layer.Through the analysis of the protocol stack routing algorithm,a routing algorithm that takes into account the routing hops and energy balance is adopted to extend the network cycle and balance the network energy.And using NS2 simulation software to compare and analyze the performance of the improved routing algorithm before and after.In order to achieve real-time data display and storage,use LabVIEW to build a host computer monitoring interface.In the system function test,the wireless module's transmission distance and packet loss rate were first tested.After simulating the system's future work environment,the data will be transferred to the LabVIEW monitoring interface,realizing the real-time display of monitoring data on the upper level,and generating historical reports;Finally,the improved algorithm was verified by experiments.