Analysis of Pointing Scan Data of the Sheshan 13 m Radio Telescope

The Sheshan 13 m radio telescope is designed as a new generation of astrometric and geodetic very long baseline interferometry (VLBI) observation system, equipped with 2-14 GHz broadband receiver and X/Ka dual-band receiver. Pointing precision is one of the most important technical specifications of radio telescopes, typically about one tenth of the beam width at the highest observation frequency. For the Sheshan 13 m radio telescope, the required pointing precision is about 18 as at 32 GHz of Ka band. Based on the pointing scan data of the telescope, the method of establishing pointing correction model is discussed, including the curve fitting of the power measurements of extragalactic sources, the tests on the effect of the integration time, and the parameter setting of the pointing correction model. The pointing precision of the telescope is measured and estimated. The resulted pointing correction model can be used as the basis for the system debugging and improvement. It is also the guarantee for the measurement of the systematic technical specifications and precisely tracking of observation target. The data analysis model and analysis process can be used for the daily pointing precision check of the observation system, and can also be used for similar engineering measurement as reference.