结合菲涅尔理论的免携带设备定位

针对免携带设备定位DFL( Device Free Localization)精度低，近距离定位目标不易区分等问题，提出了一种结合菲涅尔理论的定位估计方法。该方法首先通过无线层析成像RTI( Radio Tomographic Imaging)原理，粗定位出人体目标位置，其次计算环境参量，划分限制区域，考虑肩宽、头宽等具体人体参数，对限制域中满足菲涅尔理论的位置点进行拟合加权，实现精确定位；在出现近距离目标时，对比人体参数的实验值与理论值，判断是否为多目标。实测数据下的定位仿真结果表明，与传统的RTI方法相比，该方法在定位的准确度上提高了30％，同时实现了近距离目标数目的判决。

Device Free Localization with wireless networks based on Fresnel theory

In allusion to problems such as low accuracy of Device Free Localization,uneasy differentiation of location targets within a short distance etc.,this paper proposes a localization estimation method based on the theory of Fres￣nel. This method roughly identifies the localization of human body at first through Radio Tomographic Imaging ( RTI ) principle. The second step is to calculate environmental parameters and divide the restricted area;meanwhile,in order to realize accurate positioning,weighted fitting is conducted to the positions within the restricted area which meet the demand of Fresnel by taking specific body parameters,such as the breadth of shoulders and head,into consideration. Thirdly,when targets within a short distance appear,the comparison between the experiment value and theoretical value of human parameters should be made,in order to identify whether there are multiple targets. According to simulation results,compared with traditional RTI method,this method improves the degree of accuracy by 30% in terms of positioning in our experiment;at the same time,the number of targets within a short distance can also be identified.