关键词: 无线传感器网络, 近似三角形内点测试法（APIT）算法, 中位线, 接收的信号强度指示（RSSI）技术, 信号强度

Abstract: Aiming at the problem of low localization accuracy for APIT localization algorithm in wireless sensor network, an improved APIT algorithm is proposed. The improved algorithm presents a new test method of points to overcome the shortcoming of low localization accuracy which is caused by InToOut and OutToIn errors. To further improve the positioning accuracy, the algorithm adopts the medium line to reduce the localization area of triangle in traditional APIT algorithm. The improved algorithm has low complexity and never requires any additional hardware support. Simulation results show that the proposed algorithm keeps high localization accuracy under different anchor density and communication radius. Therefore, it meets the needs for the most node positioning in wireless sensor networks.

Key words: Wireless Sensor Networks（WSNs）, Approximate Point-In-Triangulation test（APIT） algorithm, medium line, Received Signal Strength Indicator（RSSI） technology, signal strength