摘要
针对明安图射电频谱日像仪(Mingantu spectral radioheliograph, MUSER)天线高指向精度动态跟踪要求,同时为降低非理想因素对复杂系统天线指向测量影响,提出校准天线指向的组合方法.先用网格法测量天线的双圆极化多频率通道立体方向图定性评估系统测量链路状态,后对太阳运行轨道进行十字跟踪扫描测量天线指向偏差,再用最小二乘法拟合获得天线指向模型的8个参数.国家天文台明安图观测基地的2台20 m地平式天线将在MUSER系统观测和校准中起重要作用.对20 m天线跟踪指向进行了校准,指向偏差均方根从12'改善到4.4',验证了方法的可行性,为类似复杂系统的相关工作提供了借鉴和参考.
To get good antenna tracking pointing accuracy under imperfect measurement link status of complicated system, methods and measurements of cubic radiation patterns and cross scanning-and-tracking are proposed for the two 20 m Az-El antennas, which will be updated to take part in the observation and calibration of Mingantu spectral radioheliograph(MUSER), a powerful instrument dedicated for solar radio imaging observation. Least square method is also used to obtain the 8 parameters of the 20 m antenna pointing model. After calibration, the pointing accuracy is improved from about 12'(rms) to about 4.4'(rms), testifying the reliability of the proposed methods and providing a good reference for other complicated telescope systems.
引文
[1] 颜毅华,张坚,陈志军,等.关于太阳厘米一分米波段频谱日像仪研究进展[J].天文研究与技术,2006,3(2):91-98.YAN Y H,ZHANG J,CHEN Z J,et al.Progress on Chinese solar radioheliogragh in cm-dm wavebands[J].Astronomical research and technology,2006,3(2):91-98.(in Chinese)
[2] 高冠男,汪敏,施硕彪,等.云台40 m射电望远镜的指向误差校正[J].天文研究与技术,2007,4(2):188-194.GAO G N,WANG M,SHI S B,et al.Pointing Calibration for the 40 m Radio Telescope in Yunnan Observatory [J].Astronomical research and technology,2007,4(2):188-194.(in Chinese)
[3] 王锦清,赵融冰,虞林峰,等.TM65m射电望远镜L、S、C、X频段天线性能测量[J].天文学报,2015,56(3):278-294.WANG J Q,ZHAO R B,YU L F,et al.Antenna performance measurements in L,S,C,and X bands for TM65m radio telescope [J].Acta astronomica sinica,2015,56(3):278-294.(in Chinese)
[4] 窦玉江,Dale Gary,颜毅华,等.关于单天线跟踪指向校准和双天线基线校准的探讨[J].天文研究与技术,2009,6(3):202-208.DOU Y J,DALE G,YAN Y H,et al.Search of the methods for calibration the single-antenna tracking/pointing and baselines of pairs of antennas [J].Astronomical research and technology,2009,6(3):202-208.(in Chinese)
[5] 秦顺友,耿京朝,王小强.多波段50米射电望远镜天线方向图测量[C]//第11界全国遥感遥测学术研讨会论文集,2008:461-476.
[6] 虞林峰,王锦清,赵融冰,等.TM65m射电望远镜指向模型的建立[J].天文学报,2015,56(2):165-177.YU L F,WANG J Q,ZHAO R B,et al.Pointing Model Establishment of TM65m Radio Telescope [J].Acta astronomica sinica,2015,56(2):165-177.(in Chinese)
[7] CONDON J J,YIN Q F.Offset pointing calibrators for large radio telescopes[J].Publications of the astronomical society of the pacific,2001,113(3):363-365.
[8] 焦永昌,文园,张福顺.一种有效的天线三维辐射方向图计算方法[J].电波科学学报,2008,23(4):229-234.JIAO Y C,WEN Y,ZHANG F S.An efficient algorithm for calculating three-dimensional radiation patterns of antennas [J].Chinese journal of radio science,2008,23(4):229-234.(in Chinese)
[9] 秦顺友.口径天线方向性系数和增益的快速估算方法[J].电波科学学报,2002,17(2):192-196.QIN S Y.Method of fast estimating aperture antenna directivity and gain [J].Chinese journal of radio science,2002,17(2):192-196.(in Chinese)
[10] 安涛,陈骁,MOHAN P,等.射电频率干扰的消减[J].天文学报,2017,58(5):18-39.AN T,CHEN X,MOHAN P,et al.Radio frequency interference mitigation [J].Acta astronomica sinica,2017,58(5):18-39.(in Chinese)