基于UWB与PDR的井下人员融合定位方法

A fusion positioning method for underground personnel based on UWB and PDR

  • 摘要: 现有超宽带(UWB)与行人航位推算(PDR)融合定位方法大多忽略了非视距(NLOS)环境下的定位误差校正,以简单的阈值划分作为NLOS环境判断依据,而阈值划分在很大程度上与定位场景及场地大小相关。针对上述问题,提出一种考虑NLOS环境的基于UWB与PDR的井下人员融合定位方法。首先,利用UWB技术进行井下人员位置解算,通过三边定位算法得到人员初步位置后,使用最小二乘法对位置进行优化,通过多项式拟合实现NLOS环境下基站和标签之间实际值和测量值之间的拟合,减小NLOS环境下的测距误差,提高定位精度。其次,采用PDR算法对步态进行识别和分析,PDR算法使用惯性导航传感器采集的步态数据,通过步态识别、步长估计和方向估计,实现目标位置的更新;然后,通过卷积神经网络(CNN)−长短期记忆(LSTM)网络分析信道脉冲响应(CIR)特征,实现视距(LOS)/NLOS识别,解决NLOS环境判断存在场景限制的问题;最后,根据LOS/NLOS识别结果确定融合系数,实现UWB和PDR定位结果融合。测试结果表明:多项式拟合后UWB平均测距误差降低0.59 m;LOS/NLOS识别的平均准确率为95.3%,召回率和F1分数均在90%以上,验证了CNN−LSTM具有较好的识别效果;融合定位方法的平均误差为0.31 m,较UWB降低1.57 m,较PDR降低1.41 m。

     

    Abstract: Most existing fusion positioning methods for ultra-wideband (UWB) and pedestrian dead reckoning (PDR) ignore the correction of positioning errors in non line of sight (NLOS) environments. The methods use simple threshold division as the basis for NLOS environment judgment, which is largely related to the positioning scene and site size. In order to solve the above problems, a fusion positioning method for underground personnel considering NLOS environment is proposed. Firstly, UWB technology is used to calculate the position of underground personnel. After obtaining the preliminary position of personnel through the trilateral positioning algorithm, the least squares method is used to optimize the position. Polynomial fitting is used to achieve the fitting between the actual value and the measured value between the base station and the tag in the NLOS environment, reducing the ranging error in the NLOS environment and improving the positioning precision. Secondly, the PDR algorithm is used for gait recognition and analysis. The PDR algorithm uses gait data collected by inertial navigation sensors to update the target position through gait recognition, step size estimation, and direction estimation. Thirdly, the convolutional neural network (CNN) - long short term memory (LSTM) network is used to analyze the features of channel impulse response (CIR) and achieve line of sight (LOS)/NLOS recognition. It solves the problem of scene limitations in NLOS environment judgment. Finally, the fusion coefficient is determined based on the LOS/NLOS recognition results to achieve the fusion of UWB and PDR positioning results. The experimental results show that after polynomial fitting, the average ranging error of UWB is reduced by 0.59 m. The average accuracy of LOS/NLOS recognition is 95.3%, and the recall rate and F1 score are both above 90%, verifying that CNN-LSTM has good recognition performance. The average error of the fusion positioning method is 0.31 m, which is 1.57 m lower than UWB and 1.41 m lower than PDR.

     

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