佘山13 m口径射电望远镜指向扫描数据解析

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

  • 摘要: 佘山13 m射电望远镜作为新一代天体测量与空间大地测量甚长基线干涉测量系统,配备有2~14 GHz宽频接收机和X/Ka双频接收机。指向精度是射电望远镜性能的重要指标之一,一般要求好于最高配置频率波束宽度的1/10。对于佘山13 m口径射电望远镜,Ka波段32 GHz时的指向精度约为18 as。基于该望远镜的指向扫描实测数据,探讨了指向改正模型建立方法,包括测量功率曲线拟合、积分时间影响分析、指向改正模型参数设置等,实测评估了该望远镜的指向精度。所得指向改正模型可作为系统调试与改进的依据,也是望远镜系统指标测量和观测目标精确跟踪的保障,数据解析模型与分析流程可用于测量系统的日常指向精度检核,也可供类似工程测量参考。

     

    Abstract: 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.

     

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