The consistent of laser pointing and theodolite tracking

Abstract

The distance between the laser optical axis and the tracking optical axis of the theodolite (axis shift) and the parallelism error of the optical axis cause the tracking position of the theodolite to be inconsistent with the laser pointing position.The analysis of the influence of off-axis and parallelism errors shows that a large amount of shift and parallelism errors will lead to inconsistencies between the laser pointing and the theodolite tracking pointing, which in turn leads to an increase in the blind zone of the laser ranging, a decrease in the operating distance and the accuracy of target positioning. A dynamic correction method for laser pointing based on bias tracking is proposed. By keeping the target always at the center of the laser beam and keeping the laser ranging position consistent with the theodolite tracking and locking position, it effectively solves the effect of laser edge energy drop on the operating distance. For a certain type of theodolite, the blind spot of the target can be reduced from 1 km to 82 m. At the same time, in view of the problem that the bias tracking algorithm needs the initial distance of the target to start the bias tracking, a one-dimensional search method for the target with unknown initial distance is proposed, which greatly improves the search efficiency of the target with unknown initial distance. The method in this paper solves the problem of the consistency between the tracking position of the theodolite and the pointing position of the laser, and greatly reduces the limitation on the shift and parallelism of the laser optical axis and the theodolite tracking optical axis