以国产机载激光扫描仪内较独特的扫描四棱塔镜为基础，提出了四棱镜的误差模型，并分别建立了垂直与水平方向的定位误差模型，依据该模型定性定量分析了对定位精度的影响，研究表明，四棱塔镜误差在垂直与水平方向对定位精度的影响趋势不同，均与扫描角有关，并随测距值的增大而增大。其中，垂直误差在X 方向对定位精度的影响远远大于Y、Z 方向。水平误差在Y 方向影响呈抛物线趋势，Z 方向与横滚角的影响相似。由分析可知，四棱塔镜误差对定位精度的影响较大，必须在转镜设计及加工、主机系统装调及部件集成优化、主机系统检校三个环节严格控制以消除或削弱此误差，研究该误差对机载激光雷达系统定位精度的提高有着重要影响。

The error model of four-prism based on the unique scan four-prism tower mirror of domestic airborne laser scanner is put forward. And the position error models in horizontal and vertical direction are established respectively. The effect of positioning accuracy in qualitative and quantitative aspects are analyzed. The analysis demonstrates that the influence of error in the vertical and horizontal direction is different, which is related to the scanning angle and increases with the increasing of scanning distance . The vertical error in X direction is bigger than Y、Z directions. The influence of horizontal error is parabolic trend in Y direction, and seems like the influence of roll in Z direction. The analysis shows that the four-prism tower mirror error has the significant influence on the positioning accuracy, the three links of the design and processing of the mirror, the integrated of components and the host system calibration must be strict controlled in order to eliminate or weaken this error, the study of error has the important influence on improve the airborne laser radar system positioning accuracy.