为了确定水平式光电望远镜的各主要误差对观测精度的影响，提高望远镜的指向精度，对它的目标定位误差进行了分析。针对水平式望远镜的结构特点，通过分析从被测目标到望远镜相面产生目标定位误差的光、机、电等各种误差因素，建立了水平式望远镜目标定位测量方程。应用蒙特卡罗法进行误差仿真，预测出水平式望远镜的目标定位误差，并对各误差的敏感性进行了分析。选取敏感性高的误差项建立误差补偿模型，对实拍星体误差进行补偿实验，结果表明：补偿后经轴转角误差标准差从66.4″降低到3.3″，下降了95%；纬轴转角误差标准差从49.4″降低到 5.6″，下降了89%。所用方法和模型能够对主要误差进行分析和预测，可为水平式光电望远镜的总体设计提供参考。

The orientation errors of an alt-alt photoelectric telescope are analyzed to determine the effects of the main errors of telescope on measuring accuracy and to improve the pointing precision.By analyzing optical, mechanical and electrical errors from a measured target to the telescope picture, the measuring equations of alt-alt telescope are established. Then,by using Monte Carlo method, the orientation errors are forecasted and the sensitivity of errors to pointings is analyzed.Furthermore,an error correction model is built based on the high sensitivity errors. The result of correction test indicates that the standard error of the longitude axis rotation angle has reduced by 95% from 66.4″ to 3.3″, and that of the latitude axis rotation angle has reduced by 89% from 49.4″to 5.6″. These results show that the model and the method not only can analyze and synthesize the main errors, but also can provide a reference for the whole design.