一种非视距三维超声波室内定位系统研究

Research on Non-line-of-sight 3D Ultrasonic Indoor Positioning System

目的针对超声波室内定位系统在非视距定位中精度较低的问题,为减少非视距环境误差与时钟同步等硬件误差,从定位系统整体出发提出一种非视距环境下基于对射式测距的超声波定位系统。方法利用差分修正Chan-Taylor算法结合Chan算法与Taylor级数展开算法的优势,通过Chan-Taylor算法估计空间中已知坐标点并记录其误差信息,以实际坐标为参考点,运用相邻范围内参考点对未知点差分加权,修正该点经Chan-Taylor算法的初始估计坐标,得到最终位置。为简化定位系统复杂度,提高视距环境定位精度,提出改进差分修正Chan-Taylor算法,减少初始参考点密度,将符合参考点最小间隔条件的待测点经差分修正后的估计坐标记为新参考点,优化原参考点体系误差信息分布情况。结果算法仿真实验结果表明:在非视距环境下,差分修正Chan-Taylor算法在不同参考点分布区域的平均误差与Chan算法和Chan-Taylor算法相比减小6.43%到37.46%;改进差分修正Chan-Taylor算法在视距定位中平均定位误差减少至少11.15%,均方根误差值FRMSE降低22.59%。搭建超声波室内定位系统以验证改进差分修正算法的定位精度,实验结果表明:定位误差范围在3~7.5 cm,其中90%的误差值小于6 cm,与Chan-Taylor算法相比提高28.23%。结论该超声波室内定位系统在非视距定位中精度有明显提高,在视距定位中提升较小。可通过提高Chan-Taylor算法精度和改进参考点加权函数以优化定位算法;通过优化超声波接收端信号识别方法,增大发射端信号范围以在硬件方面进一步提升该系统定位精度。

Objective In response to the issue of low precision of ultrasonic indoor positioning system in non-line-of-sight positioning,a novel ultrasonic positioning system based on retroreflective ranging in non-line-of-sight environments was proposed starting from the overall positioning system to reduce errors in non-line-of-sight environments and hardware errors such as clock synchronization.Methods Utilizing the advantages of the differential corrected Chan-Taylor algorithm combined with the Chan algorithm and Taylor series expansion algorithm,the Chan-Taylor algorithm was used to estimate the known coordinate points in space and record their error information with actual coordinates as reference points.By differentially weighting unknown points with neighboring reference points within a certain range,the initially estimated coordinates obtained by the Chan-Taylor algorithm were corrected to obtain the final position.In order to simplify the complexity of the positioning system and improve the positioning accuracy in line-of-sight environments,an improved differential corrected Chan-Taylor algorithm was proposed.This involved reducing the initial density of reference points and marking the estimated coordinates of target points that meet the minimum interval conditions for reference points after differential correction as new reference points to optimize the distribution of error information in the original reference point system.Results Simulation experiments of the algorithm showed that in non-line-of-sight environments,the average error in different reference point distribution areas of the differential corrected Chan-Taylor algorithm was reduced by 6.43%to 37.46%compared with the Chan algorithm and Chan-Taylor algorithm.The improved differential corrected Chan-Taylor algorithm reduced the average positioning error in line-of-sight positioning by at least 11.15%,with a decrease of 22.59%in root mean square error.The positioning accuracy of the improved differential corrected algorithm was validated through the construction of an ultrasonic indoor positioning system,with experimental results showing a positioning error range of 3 cm to 7.5 cm,where 90%of the errors were less than 6 cm,representing a 28.23%improvement compared with the Chan-Taylor algorithm.Conclusion The ultrasonic indoor positioning system shows a significant improvement in accuracy in non-line-of-sight positioning,with a smaller improvement in line-of-sight positioning.The positioning algorithm can be optimized by improving the accuracy of the Chan-Taylor algorithm and enhancing the reference point weighting function.Hardware improvements,such as optimizing the ultrasonic receiver signal recognition method and increasing the signal range at the transmission end,can further enhance the positioning accuracy of the system.