基于接收信号强度指示的AP簇测距方法
AP Cluster Ranging Method Based on Received Signal Strength Indication
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摘要: 对移动目标的高精度测距是室内定位的关键。室内环境中无线接入点(Access Point, AP)采集的移动目标设备的接收信号强度指示(Received Signal Strength Indication, RSSI)受阴影衰落波动严重。受到RSSI采集频率和目标机动能力的限制,AP采集到的RSSI样本量少,导致基于RSSI测距精度差。为提高基于RSSI对移动目标测距的精度,本文提出了基于RSSI的AP簇测距(AP Cluster Ranging, APCR)方法。该方法通过对多个AP进行位置约束组成AP簇采集移动目标设备的RSSI,在相同采集频率下可获得更多的RSSI样本。利用RSSI波动特点,使用最大值选取和Dixon检验相结合的方式从AP簇采集的RSSI样本中筛选出高质量的RSSI样本,以提高对移动目标的测距精度。仿真和实验结果表明,与传统RSSI处理方法相比,本方法在室内环境简单或复杂时都具有更高的测距精度,在少量RSSI采集次数下同样能保持较高精度,更能满足对移动目标测距的需求。Abstract: High precision ranging of moving target is the key to indoor positioning. The received signal strength indication (RSSI) of the moving target device collected by the wireless access point (AP) in the indoor environment fluctuates severely due to shadow fading. Limited by RSSI sampling frequency and target mobility, the RSSI sample size collected by AP is small, resulting in poor ranging accuracy based on RSSI. In order to improve the accuracy of moving target ranging based on RSSI, an AP cluster ranging (APCR) method based on RSSI is proposed. In this method, the RSSI of mobile target device is collected by AP cluster with position constraints on multiple APs, this increased the number of samples at same collection frequency. Based on the fluctuation characteristics of RSSI, a combination of maximum value selection and Dixon test is used to screen out high-quality RSSI samples from AP cluster collected RSSI samples to improve the ranging accuracy of moving targets. Simulation and experimental results show that, compared with the traditional RSSI processing methods, this method has higher ranging accuracy in either simple or complex indoor environment. It has high accuracy in the case of a small number of RSSI collect times, which can better meet the requirements for the ranging of moving target devices.