Research And Application Of Localization Algorithm Based On ZigBee Wireless Sensor Network

As a new short-range communication technology, wireless sensor network is subject to more and more attention with the broad development prospects in the monitoring and control applications. Establishing a low-cost, high-precision positioning system is one of the hot research field, using wireless sensor network to determine the location of the incident or derive the node position of news. Based on the ZigBee protocol for wireless sensor network, the node localization algorithm is studied in this paper, and is applied to precision irrigation control system.This paper firstly describes the background of wireless sensor network node localization and the main domestic and international wireless location technology, analyzes the development trend of wireless location technology and the existing problems. On the basis of understanding the structure and characteristics of wireless sensor network, this paper explained the basic principles of wireless node location, specified and classified the various node localization algorithm. Then the evaluation criteria of wireless location are given.Considering the volume of sensor nodes, power consumption, cost and other factors, we use the received signal strength indicator (RSSI) as the method of measuring distance between the nodes. Through the establishment of mathematical model gives the relationship between distance and RSSI. In the completion of the measuring distance as the first phase, we should use a certain location algorithm to complete the position stage as the second phase. In this paper, we use a weighted centroid location algorithm by weight modifying to calculate the coordinates of the node. Through the measuring distance experiment and the positioning experiment in the actual environment, the formula for short-range positioning is obtained. After the experimental results are compared with the results of conventional positioning method, it shows that the weighted centroid localization algorithm by weight modifying has obvious advantages. It can meet certain requirements of positioning.With the sensor nodes independently developed, this paper also designs a irrigation control system based on ZigBee, implements the software development of WSNView monitoring system and gives details of the system design and design process of each functional module. Beijing Forestry University established a research base for precision irrigation control demonstration, which is about 100 acres in the Qianlingou village, Changping District in Beijing. The system is running in this real environment for about four months. And the results show that the software has good stability to meet the requirements of a precision irrigation control and the conservation and efficient water use. Finally, network condition assessment, another verification of location algorithm, trend analysis of soil moisture and analysis of water used are done by using the collected data from experiments.