单圈绝对式电子经纬仪测角信号处理

Signal processing algorithm of a single-track absolute encoder for photoelectrical theodolite

为实现快速、高精度角位移测量,提出了一种单圈绝对式电子经纬仪测角信号处理算法。只需刻画脉冲左右边沿在阈值附近各2个采样点就可以快速估计出脉冲宽度和脉冲中心坐标;对现有文献细分方法进行改进,给出了基于多组刻画脉冲中心求解高分辨力细分角的公式;并对算法时间复杂度和抗噪声性能分别进行了分析与仿真。实验结果表明,本方法在水平方向上测角误差标准差仅为2.5″,平均每秒钟可测角输出25次,具有实现简单、只需较少计算量就可以获得较高测量精度的优点。研究结果可以为单圈绝对式电子经纬仪、全站仪提供一种新的测角信号处理实用方法。

To realize a fast and high-precision angular measurement method,this study focused on the signal processing algorithm of a single-track absolute encoder,which can be easily applied to photoelectrical theodolites.Using this algorithm,the grating line center and pulse width could be quickly estimated with only two sampling points of the rising and falling edges,by setting a threshold for the observed grating data.To improve the existing subdivision method,a high-resolution subdivision algorithm for angular measurement was provided by calculating multiple grating line centers.We also analyzed the algorithm's time complexity and anti-noise ability by simulation.Experiments were performed to evaluate the measurement precision,output stability,and running speed.The results showed that the standard deviation of error was within 2.5 seconds,and the rate of angular output was 25 times per second.This algorithm is easy to implement and has merits of both limited computation and high-precision.Thus,a new angular measurement signal-processing algorithm,which can be applied to a single-track absolute encoder for a photoelectrical theodolite or total station instrument in the future,can be developed with the results of this research.