Optimization and accuracy analysis in pose measurement of the subreflectors of large antennas based on stereo structured light

Abstract

The accuracy of the pointing error in the subreflector is of great importance to the large steerable radio telescope, so the measurement of the six degree-of-freedom (DOF) poses of the subreflector is crucial, which are measured by the detector and the laser array. The errors in the pose measurement system of the subreflector contain random measure errors and fitting iteration errors; all of them will add up to the pose measurement, which affects the accuracy of the six DOF parameters. This paper proposed the accuracy analysis method in the pose measurement of the subreflector of large antennas, which includes the error in the variable model in laser three-dimensional point space linear fitting, iterative accuracy analysis of spatial equations in Newton’s downhill method, and the analysis of the adjustment theory of the Bursa model. The experimental results show that the measure time in six-DOF poses of the subreflector in a large-aperture antenna is at most 0.5 s, while the measurement accuracy error of translation is within 0.0131 mm and the error of rotation is within 0.2323°, which indicates that the pose measurement method of the subreflector in large antennas based on stereo structured light is efficient and applicable enough to analyze the measurement system accuracy.