Batch Measurement and Calibration Method of DSRT Three-axis Low Frequency Antenna Pointing Error postprint

Abstract: Daocheng Solar Radio Telescope(DSRT) is an important part of the Solar Interplanetary exploration subsystem of the second phase of The Chinese Meridian Project. It operates in the 150\;MHz to 450\;MHz frequency band and provides high-resolution spatial and temporal images of solar eruption brightness and temperature. Aiming at the high precision pointing measurement of the DSRT antenna and the requirement of batch calibration and correction of pointing errors, this paper establishes the 3-parameter, antenna encoder zero point offset pointing error model by quaternion rotation transformation method according to the unique three-axis mount system of DSRT. In this paper, the drift scanning method based on radio source is proposed to obtain the radiation pattern of 16 antennas and determine the boresight according to the two-dimensional power pattern to accurately measure the pointing error of the DSRT antenna. Finally, the least square method is used to get the model parameters, and the antenna control software is used to adjust the encoder zero point of each axis, and then the adjustment results are verified. The results show that the pointing calibration method is reliable and effective. The pointing accuracy of 16 antennas after correction is within 0.5$^\circ$, which is significantly better than the pointing error of 3.5$^\circ$ before calibration, and the error is less than one-tenth of HBPW(half power beam width) under the maximum working frequency of the DSRT antenna.