基于电磁波及超声波联合测距的井下定位方法

研究煤矿井下电磁波、超声波联合定位方法，根据井下巷道的空间结构特点，由锚节点和网关节点形成无线传输网络，网关节点布置在巷道的端点，锚节点一字排开等间距吊挂在巷道顶部中央，使巷道内任意位置都至少有两个锚节点接收到移动节点发射的电磁波信号。 移动节点通过判别锚节点电磁波信号强度确定移动节点与锚节点的位置关系；移动节点采用基于超声波的TOF检测方法进行巷道横向测距，移动节点和锚节点节采用基于电磁波信号强度的对数-常态分布模型进行巷道纵向测距，最终确定移动节点的二维坐标。 仿真结果表明，提出的定位方法误差较小，超声波在巷道横向的测距误差很小，巷道纵向50 m范围内，最大误差不超过5 m。 联合定位方法使用少数锚节点获得高定位精度，可以应用于煤矿井下。 

A Positioning Method in Mine Tunnel Based on Joint Electromagnetic Wave and Ultrasonic Distance Measurement

A joint electromagnetic wave and ultrasonic localization method was presented. According to the space structure of the underground tunnel, the wireless transmission network was formed by anchor nodes and gateway nodes. The gateway nodes were placed in the end of the branch tunnels and the anchor nodes were hanged in line arrangement from the roof of the tunnels. These anchor nodes have same intervals, the length of which was limited to make sure that the electromagnetic wave signal emitted by one mobile node at any position of the tunnels can be received by at least two anchor nodes. The mobile node judges the position relations between the anchor node closest to it and itself through the received signal strength of anchor nodes; the mobile node makes transverse distance measurement through TOF detection method based on ultrasonic. The mobile node and anchor node make longitudinal distance measurement based on signal strength of electromagnetic wave through log-normal distribution model. The simulation results show that this method has smaller positioning error, ultrasonic in roadway horizontal distance measurement error is small, maximum error is not more than 5 m at 50 m range of tunnel longitudinal. The method presented by the paper could provide high positioning accuracy with a small number of anchor nodes.