三轴误差对光电经纬仪测角的影响

Impact of three-axis error on angle measurement of photoelectric theodolite

轴系是决定光电经纬仪测量精度的关键组件,三轴误差是影响经纬仪测角精度的主要因素。根据经纬仪三轴地平结构,建立了球面坐标系并用球面三角学推导了轴系误差引起测量误差的精确数学模型。对精确模型简化得到了适用于工程应用的简化模型。仿真表明,照准差和水平轴倾斜对方位角测量影响较大,目标俯仰角越大影响越严重;对俯仰角测量影响较小,可以忽略不计;垂直轴倾斜对方位角、俯仰角测量的影响是目标方位角正弦函数。为光电经纬仪的精度分析、误差分配和误差修正提供了有效参考途径。

Shafting is the key module of photoelectric theodolite to decide the measurement precision, three - axis error is the main factor affecting the accuracy of photoelectric theodolite angle measuring. According to the three ax- is horizontal structure, the spherical coordinate system was set up and the accurate mathematical model of the measurement error caused by shafting error was deduced using spherical trigonometry knowledge. The simplified model suitable for engineering application was obtained by simplifying the accurate model. The simulation results show that collimation error and horizontal axis tilt have great effect on azimuth angle measuring, the larger target pitch angle is, the more serious the effect is. Howerer, collimation error and horizontal axis tilt has little influence on pitch angle measuring, and the influence can be neglected. The effect of vertical axis tilt error on azimuth angle and elevation angle measuring is the sine function of target azimuth. The influence of vertical axis tilt on azimuth angle and elevation angle measuring is the sine function of the target azimuth. It can provide an effective method to analyze accuracy, distribute and correct error of the photoelectric theodolite.