Research Of A Water Environment Monitoring System Based On Wireless Sensor Networks

Water environment monitoring is essential for water resources protection, traditional methods of the water environment monitoring mainly includes:artificial sampling monitoring, water quality monitoring stations monitoring, aquatic organisms monitoring, and remote sensing monitoring. Each of these methods has its advantages and disadvantages, and they could not complete the task of real-time monitoring in large range. Wireless sensor network (WSN), as a network system which is used to perceive the environment, and WSN have applied extensively in the field of environmental monitoring. The technology of wireless sensor network has remarkable advantage in water environment monitoring, which could overcomes the shortages of traditional methods of the water environment monitoring, including worse real-time, costly, small monitoring area, etc.In this paper, we carefully analyze the characteristics of wireless sensor network and its applicable applications, and have a survey of traditional methods of the water environment monitoring, then we design a water environment monitoring system based on wireless sensor network. It consists of three parts:data acquisition network, ZigBee/GPRS gateway, remote data processing center. This system is suitable for the complex water environment monitoring, including lakes, rivers, swamps, etc. This work is partially supported by National Basic Research Program of China (National project973). The project number is2009CB320300.In the paper, we describe the hardware and software architecture of the three parts of the water environment monitoring system. The design of hardware part mainly includes the design of data acquisition node, the design of the sensor signal conditioning circuits, the ZigBee/GPRS gateway interface design. And the design of software part mainly includes the transplantation of ZigBee protocol stack, the program design of data acquisition, the program design of data upload based on the TCP technology, equipment remote control program design. We also make a detailed description about the location planning for the water environment monitoring nodes, including the selection of sampling section, the layout of sampling vertical line, the sampling point layout.Finally, we tested the water environment monitoring system by a series of monitoring experiments in a lake. And we designed a multi-sensor data fusion system for this water environment monitoring system, which includes the redundant data fusion by self-adapting weighting fusion algorithm and the complementary data fusion by an elastic BP neural network. The experiments verify the repeatability and correlation of this water environment monitoring system. It could accomplish the task from the water quality data collection to the water quality evaluation excellently.