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Wireless sensor network is a new information processing technology, which integrates sensor technology, embedded technology, electronic technology and radio technology. As a new technology, wireless sensor network is used in national defense science and technology, environmental monitoring, space exploration, health and medical, precision agriculture, traffic management, and other areas of discaster resistance, to achieve large-scale detection and tracking. Node localization technique-the main technology for wireless sensor networks,is the premise to achieve object recognition, monitoring and tracking. Current Localization Schemes for Sensor Networks are in a wide range, Range-Based and Range-Free Localization Schemes are widely in used. Considering the cost and power consumption, Range-Free Localization seems more advantageous than Range-Based Localization. People have paid more attention to Range-free location technology for WSN, which is a special self-organizing network. Therefore, this article focuses on Range-free localization algorithm for wireless sensor nodes in the Network Localization Technology. First, I summarized the architecture of wireless sensor networks, characteristics, basic principles and evaluation criteria for system performance. Then, I discussed the localization algorithm’s classification for WSN, and studied the typical location algorithms of Range-Free Localization Schemes in details;after that, I analyzed the APIT localization algorithm in Range-free localization algorithm, and researched an improved APIT algorithm against the problem, that the localization accuracy is low when anchor node ratio and node density is low, and discussed the relationship between the average location error and anchor node ratio, or the number of nodes. Next, an optimization method with GA algorithm was proposed against the problem of low localization coverage in traditional algorithm and improved algorithm, and simulation analysis and performance evaluation was made in matlab. At last, the future work was prospected based on the results of the wireless sensor network development.
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