Objectives Structural deformation of dual-reflector antenna with large aperture and high surface precision will greatly decrease its electrical performance, and performing surface measurement and adjustment is of great importance. For the problem of online adjustment of structural deformation in engineering, one online adjustment method is presented based on a laser tracker measuring system.
Methods Assumed that a laser tracker is installed on the back frame of sub-reflector and laser probe can move along the guideway on the edge of sub-reflector, with its ability of automatic target search, it will be possible to realize automatic measurement during antenna operation. Based on the above measuring strategy, we derive the pose adjustments of sub-reflector and the panel adjustments of main reflector based on the concept of best-fit reflector using the measured surface information of main reflector. The proposed method can achieve the online measurement, and because the measuring system is fixed on the sub-reflector, there is no need to measure the position and attitude of the sub-reflector again.
Results For a 35 m reflector antenna, the adjustment precision is discussed, and simulation results show that the surface error is reduced to ±1 mm from ±3.5 mm when only the sub-reflector is adjusted and the surface error is nearly zero when the sub-reflector and main reflector are both adjusted.It should be noted that the measurement accuracy of the whole measuring system should be further considered in engineering.
Conclusions The proposed method can greatly improve reflector's surface accuracy and electromagnetic performance, and it can provide helpful guidance for automation closed-loop surface adjustment of large dual-reflector antenna.