英文摘要 | With the development of communication engineering, integrated circuits, sensors and microelectronic technologies, Wireless Sensor Network (WSN) has been improved significantly. WSN has been implemented widely in the system monitor due to its low-cost, small size, self-organization as well as large scale. A WSN based monitoring system can collect the sensor data and environmental parameters with the high efficiency, and provide the alarm for the monitor center. This thesis focuses on a series of key problems in the environmental monitor with WSN, such as establishing WSN platform, network topology, power management and time synchronization. The main results include: 1. A monitor system based on WSN is described in detail, where system and network structures, communication protocol, hardware platform and soft design are addressed. Moreover, the smart sensor nodes expand the awareness of the sensor nodes and the video network, which consisted of wireless network cameras, provides the base infrastructure to collect video streams. 2. A novel power management algorithm is proposed, where a periodic sleep mechanism with alarm is designed. It can monitor the environment periodically and catch the exception condition. 3. In contrast to these traditional methods, such as GPS and other wireless location equipment, that synchronize the time in the global network, a local region based time synchronization algorithm is proposed. By using the feedback information from route nodes, sensors in the same region will go into the state of sleep with little communication consumption for time synchronization. 4. Design a data storage structure and database which centered the gateway node, realized through the client program or web log in access to different monitoring area of the gateway node database, query function of historical data and real-time data. 5. The large-scale farm simulation verifies the monitor system and the real experiments on the farm show the effectiveness of the proposed system. 6. Improve the communication mechanism, signal processing and sorting algorithm of position and navigation methods based on WSN and increase the reliability, accuracy and speed. |
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