| The extensive mode of growth in China causes serious water pollution, water environmentmonitoring can provide strong support to the water pollution control with tracking thespatiotemporal changes of water quality. Fixed monitoring station has been used to collect data inwater environment monitoring through traditional method. Because of the high cost to build lessnumber of monitoring station, traditional method just get the data at one spatiotemporal point andthe result can not continuously and dynamically reflect changes in the water environment inmulti-dimensional. Water environment monitoring system based on wireless sensor networkprovides a new way to solve the above problems. Wireless sensor can cover the entire watershedscale because of its low cost, meanwhile using multi-hop transmission, the data sensored can besent to host computer in real-time and the change of water environment can also be reflected bybackend server at the same time. In addition, positioning method of wireless sensor network nodehelps to determine the location of pollution sources. This paper sets water environment informationprocessing as the goal and establishs a water environment monitoring system based on wirelesssensor networks. The main contents of this dissertation are expressed as follows:Firstly, the highly integrated water environment monitoring hardware node is designed tocollect and process water temperature, water depth and PH value. Connecting CC2430and CC2591which support ZigBee protocol ensures low power and high transmission efficiency. Optimizationmethods of distance measurement based on RSSI is given for node localization.Secondly, a water environment monitoring oriented node positioning method was designed andimplemented by combining cosine positioning method and maximum likelihood estimationpositioning method. MVC framework is used to implement a background system and a mobileclient based on Android was implemented to receive data from background using XML file.Thirdly, a test system is built to verify the feasibility and functionality of the system, includingthe hardware, network, backend service and mobile client. |
