Abstract: This paper studies a localization method using Angle of Arrival（AOA） estimations by directional antenna equipped beacons in Ad-Hoc networks.The node to be localized sends a signal to its surrounding beacons. The beacons estimate the signal directions with high resolution AOA methods and calculate the distance between the node and the beacon using RSSI （Received Signal Strength Indicator）.Only one beacon is needed to estimate the location of the node in this method.When AOA estimates from two or more beacons are received，the averaging resolution method is proposed.As estimation bias is heavily dependent on antenna orientations the center-facing approach is found to give better performance in a square field.

Key words: directional antennas, Ad Hoc networks, localization, Angle of Arrival（AOA）

摘要： 提出了一种新的基于方向性天线的Ad Hoc网络节点定位算法，当锚节点装配了智能天线或自适应天线阵列这样的方向性天线时，锚节点利用高分辨率的波达方向估计方法估计出节点向锚节点发送信号的方向，并根据收到的信号功率大小估算出节点和锚节点之间的距离后，锚节点即可完成对未知节点的定位。该方法只需要利用一个锚节点就可以完成未知节点的定位，且适当改变锚节点天线的阵列摆放，就可以提高定位的精度。理论分析和仿真实验证明了所得结论。

关键词: 方向性天线, Ad Hoc网络, 定位, 波达方向估计