WSN Technology Application Research On The Landslide Monitoring System

China is a country of landslide disasters. Each year landslide disaster caused by a variety of economic losses as high as several billion yuan, thousands of casualties. Potential landslide disaster seriously threat to people's life and property safety. Developing an automation, many parameters, long period of time acquisition, and accuracy landslide disaster warning system is very necessary. With the mature of WSN technology, it has been a hot research topic that using WSN technology establish the landslide disaster monitoring system. This paper puts forward a set of landslide monitoring system whose monitored objects was groundwater, rainfall, displacement, acoustic emission signal, based on the WSN technology. This article main research contents and results are as follows:Firstly, the wireless sensor network research. Analyzed the research present situation of landslide monitoring system based on WSN, and introduced the RF transceiver NRF24L01+ enhanced ShockBurst? protocol. After that put forward a kind of WSN protocol stack which include the physical layer, data link layer, network layer, and application layer, and elaborate the design of each layer protocol. According to the needs of landslide monitoring system, we design a variety of types of radio frame and many data transmission and processing commands to facilitate system node complete ad-hoc network and process distributed data. Also, we put forward a selforganization and improved RIP protocol for landslide monitoring system WSN, by analyzing the advantages of RIP and OSPF protocol. We analyze landslide monitoring objects, have been clear monitoring parameters of the rainfall, groundwater and deep displacement. Using multi-point acoustic emission monitoring data contrast and the sound source localization method to eliminate the influence of environmental noise to the acoustic emission signal.Secondly, the system hardware design. Hardware equipment include many data acquisition nodes which were dispersed in the area of landslide and a data gathering node. In order to improve the data processing and analysis ability of node, two kinds of nodes MPU selected STM32F407 VE chip which architecture is Cortex-M4 of ARM, external memorizer used large capacity Micro SD card. The senor of acoustic emission signal selected the high quality, precision capacitor microphone of 4193, meanwhile using 12 bit successive comparative ADC inside of MPU complete sampling. The data of groundwater, rainfall and the landslide displacement sensors transmitted by a high economic and reliability RS-485 bus. The bus communication protocol is the standard Modbus-RTU protocol. The system WSN use NRF24L01+ RF transceiver that communication rate can be up to 2 Mbps. Transceiver output connect to power amplifier RFX2401 C, make the wireless communication receiving sensitivity of-94 dBm. Nodes location coordinates determination and time synchronization implement by high precision Beidou/GPS dual mode module BD-125. Furthermore, system access mobile internet through the USR-GPRS232-7S2 module to realize local system data transmission with specify the users and the remote server.Thirdly, the system software design. First, transplanting ?C/OS-II and FatFs on the MPU of this system. Then designing the low level driver of hardware and WSN protocol stack program of two kinds of nodes. Last, the data transmission between nodes and distributed data processing application program was designed.Fourthly, the system function test. After completion of nodes hardware design and debugging, tested Ad-hoc network and data more jump transmission of wireless sensor network. Then the data acquisition nodes and node functions were tested. The results show that:The monitoring objects have groundwater, rainfall and displacement, also include the acoustic emission signal of landslide, which can be more comprehensive reflect the evolution of landslide process; The WSN that based on enhanced ShockBurst? protocol make the nodes in the network flexibility and reliability, also increase the data transmission rate. Using the application of distributed data processing technology to the WSN, improve real-time performance and reliability of this system.