Research on Rapid Antenna Pointing Measurement Based on Optical Pointing Telescopes

The track unevenness has a significant impact on the pointing performance of large radio telescopes. The track unevenness related pointing measurements require a high spatial sampling density, necessitating a large number of measurement points. Given the limited number of radio pointing calibration sources, sufficient spatial sampling density must be achieved by Earth's rotation, which limits the measurement speed. OPTs (Optical Pointing Telescopes) can obtain high spatial density data independently of Earth's rotation, but the large number of measurement points still constraints the measurement speed. This paper proposed the adoption of OTF (On-The-Fly) mode in OPT observations to avoid the time-consuming process of establishing stable tracking at predetermined measurement points. To address the performance degradation of the antenna's encoder and the OPT at a high angular speed, a “bar-shaped” star extraction method based on the YOLO (You Only Look Once) approach was developed, and an encoder error model was established. Ultimately, pointing measurements at an angular speed of 1°/s were achieved. This measurement effectively detected the track unevenness effects with amplitudes of 2 arcseconds.