用于矿山等极端环境中的高精度定位算法

High-precision Localization Approach for Harsh Environments Like Mining

高精度室内定位技术在矿山、建筑、施工等多种极端环境下都有需求。基于超宽带通信(Ultra Wideband,UWB)的室内定位技术能够提供较高的定位精度,但超宽带信号易受到障碍物的干扰,并且在类似矿山等极端环境中,障碍物不可避免。因此,超宽带非视线传输(Non-Line-of-Sight,NLoS)测距成为当前的一个研究热点。当前研究大多集中在识别和消除非视线传输对超宽带测距的影响上,实际应用中,大多数情形下超宽带信号根本无法穿透障碍物,会导致定位标签只能够与2个或1个信标节点通信,但完成三边定位至少需要3个信标节点。为此,提出了一种基于目标行为分析的定位算法,该算法能够在短时间内仅剩余一个信标节点与标签通信时,也可实现高精度定位。该算法以超宽带通信为基础,使用信号飞行时间(Time of Flight,TOF)算法测距并定位。通过分析信号正常时的目标运动轨迹来判断其速度和方向,当信号不正常时(可通信的信标节点减少),可利用预测的速度和方向参数来实现辅助定位。将该算法部署在一个基于超宽带定位的系统中进行了测试,结果表明:当能够与标签通信并完成TOF算法的信标节点数量少于3个时,基于NLoS传输识别和消除的算法无法完成定位,而基于目标行为分析的定位算法依然能够实现定位,在单信标节点区域的平均定位误差为0.93 m,最大误差为1.41 m,在2个信标节点测距的区域,平均定位误差为0.64 m,最大误差为1.2 m。

High-precision indoor localization technology is required in many harsh environments such as mining,con-struction,etc..Ultra Wide Band(UWB)based on indoor localization system provides a high-precision of position,but UWB sig-nals are susceptible to obstacles.Unfortunately,in harsh environments like mining,obstacles are inevitable.Therefore,rangingin Non-Line-of-Sight penetration has become a hot research topic.Most of researchers focus on identification and mitigation ofNon-Line-of-Sight(NLo S)penetration.However,in reality,UWB signals are simply unable to penetrate obstacles in most cas-es.This situation will cause the localization tag to only communicate with two or one single beacon nodes,but at least three bea-con nodes are required to complete the trilateral localization.To address this problem,a localization algorithm based on targetbehavior analysis is proposed.By using UWB and TOF ranging,this algorithm estimates target’s speed and heading based onthe analysis of trajectory when the signal is normal.When the target enters certain areas,the number of base stations communi-cating with it is less than three,speed and heading can be used to assist in localization.The experiment of the algorithm in anUWB localization system is done.The study results show that when the number of beacon nodes that can communicate with thetag and complete the TOF algorithm is less than three,the localization algorithm bases on NLo S identification and mitigationcan not work in this situation.But the approach based on target behavior analysis can still calculate location results.The aver-age positioning error in a single beacon node area is 0.93 m and the maximum error is 1.41 m.In the area where the two beaconnodes are ranging,the average positioning error is 0.64 m,and the maximum error is 1.2 m.