Abstract: Large range course angle measurement system of medium-to-high accuracy was studied for the course angle calibration of vehicle dynamic base. The system used two area array CCDs to identify the location of a reflected spot and realized the course angle measurement of dynamic base. To avoid the impact of base vibration, a retro-reflector was used. The system is optimized for airborne application because it is simple in structure and easy to adjust. An experimental setup was built based on the estimated parameters. After the signal detected by CCDs was processed by threshold segmentation, a center of gravity sub-pixel method was used to achieve position detection. The result shows that the accuracy of position measurement is about 0.4 pixel, the course angle is immune to the base vibration, and the accuracy of the measurement is better than 1 in the measurement range of 10.