深空站区域对流层延迟模型构建及在嫦娥四号中的应用  

Construction of regional tropospheric delay model in deep space station and its application in Chang’E-4 mission

作　　者：路伟涛[1,2] 谢剑锋 韩松涛[1,2] 陈略 任天鹏[1,2] 牛东文 王美[1] 李黎 LU WeiTao;XIE JianFeng;HAN SongTao;CHEN Lue;REN TianPeng;NIU DongWen;WANG Mei;LI Li(Beijing Aerospace Control Center,Beijing 100094,China;Key Laboratory of Science and Technology on Aerospace Flight Dynamics,Beijing 100094,China)

机构地区：[1]北京航天飞行控制中心,北京100094 [2]航天飞行动力学技术重点实验室,北京100094

出　　处：《中国科学：技术科学》2019年第11期1286-1294,共9页Scientia Sinica(Technologica)

基　　金：载人航天预研项目资助

摘　　要：深空干涉测量系统实时模式下主要依赖经典模型进行对流层延迟修正,但修正效果不佳,严重限制了实时测量精度.基于此,本文构建了一种区域高精度对流层延迟模型.首先,通过对流层延迟实测值与模型值的比对确定了Saastamoinen模型天顶延迟估计的修正系数,修正后对流层天顶延迟偏差由1.24 ns降至约0.9 ps;其次,为突破Saastamoinen模型气象数据约束,提出了高程修正的UNB3m模型,建立了测站区域大气参数估计模型,大气压强、温度、水汽压的估计偏差分别约为3.9 mbar,6.7 K,0.63 mbar,由大气参数模型值与实测值得到的对流层天顶延迟偏差约为14 ps,显著增强了天顶延迟估计的实时性;最后,通过分析Niell映射函数规律,确定干映射参数a为响应的主要影响参数,进一步通过最小二乘处理得到了参数a的最佳值.结果表明在仰角10°时,对流层延迟偏差约0.3 ns,相对缩小近1个量级.利用本文所提模型,嫦娥四号探测器实时定轨残差与事后对流层延迟实测值条件下的结果基本一致,相对原始对流层模型下的定轨残差显著改善.本文所提对流层区域模型不依赖于大气参数实测数据,估计精度高,可显著改善深空干涉测量实时定轨支持能力.The very long baseline interferometry(VLBI)in China Deep Space Net(CDSN)mainly uses the classical model for tropospheric delay modification in real-time processing,while the measuring accuracy is constrained by the model performance.In view of this problem,an accurate regional tropospheric delay model is constructed.Firstly,the correction factor of Saastamoinen zenith tropospheric delay is determined by comparison of measured and estimated value,which leads to the zenith delay estimation bias reducing to about 0.9 ps from 1.24 ns.Secondly,in order to overcome the restriction of meteorological data,the UNB3m model with height correction is introduced to construct reginal atmospheric parameter estimation model,and results show that the estimation bias of atmospheric pressure,temperature and vapor pressure is about 3.9 mbar,6.7 K,0.63 mbar,respectively,moreover,the difference of zenith delay is about 14 ps when the measured and modeled meteorological data are as input,which enhances the real-time performance of zenith delay estimation.Finally,the characteristics of Niell mapping function are analyzed and the factor a in dry function is confirmed as the key parameter,whose optimal value is obtained by least-square processing.The measured data processing results show that the tropospheric delay estimation bias is about 0.3 ns when the elevation angle is 10°,which decreases nearly an order compared with the original model.Furthermore,the orbit determination error of Chang’E-4 detector is basically identical when using measured and the proposed tropospheric delay model,both results are significantly better than that of the original model.The regional model proposed here is of meteorological data independence and of high accuracy,which improves the support ability of VLBI system in CDSN for real-time orbit determination.

关 键 词：中国深空网 嫦娥四号 对流层延迟 Saastamoinen模型 Niell映射函数 

分 类 号：P22[天文地球—大地测量学与测量工程]