地基GNSS VTEC约束的大气掩星电离层误差修正方法  

Ground-based GNSS VTEC constrained ionospheric correction method for atmospheric occultation

作　　者：柳聪亮 孙越强 杜起飞 白伟华 王先毅 李伟 LIU CongLiang;SUN YueQiang;DU QiFei;BAI WeiHua;WANG XianYi;LI Wei(National Space Science Center,Chinese Academy of Sciences,Beijing 100190,China;Beijing Key Laboratory of Space Environment Exploration,Beijing 100190,China;Joint Laboratory on Occultations for Atmosphere and Climate(JLOAC),Beijing 100190,China;School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院国家空间科学中心,北京100190 [2]天基空间环境探测北京市重点实验室,北京100190 [3]掩星探测与大气气候应用国际联合实验室,北京100190 [4]中国科学院大学天文与空间科学学院,北京100049

出　　处：《地球物理学报》2020年第12期4324-4332,共9页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(41775034,41405039,41606206);中国科学院空间科学先导专项(XDA15021002);中国科学院青年创新促进会人才项目(2019151);北京市优秀人才青年骨干项目(2018000097607G380)资助.

摘　　要：介绍了一种考虑电离层沿GNSS掩星射线路径分布不对称且兼顾一阶和二阶项的大气掩星电离层误差修正新方法,它综合地基GNSS VTEC的水平变化信息和电离层模式的垂直变化信息,在沿“入射线”与“出射线”双边局部球对称假设下,估算GNSS掩星射线路径上的电子密度;进而计算一阶和二阶项弯曲角电离层误差廓线.采用太阳活动低年的2008年7月15日和太阳活动较高年的2013年7月15日两天的MetOp-A和GRACE掩星观测资料和IGS的GNSS VTEC数据,计算了GNSS大气掩星弯曲角一阶和二阶项电离层误差廓线.对比分析表明:新方法经验模型和理论模型的二阶项弯曲角电离层残差,以及经验模型与实测数据的一阶和二阶项弯曲角电离层误差均具有良好的一致性,因此该方法可用于L2信号数据质量较差或L2信号中断的掩星事件,同时修正大气掩星一阶和二阶电离层误差,从而提高弯曲角精度和掩星观测资料的利用率.Ionosphere is a major error source of Global Navigation Satellite System(GNSS)radio occultation(RO),this paper proposed a ground-based GNSS vertical total electron content(VTEC)constrained ionospheric error correction method,which accounts for the ionospheric asymmetry along the occultation ray path as well as the first-and second-order ionospheric terms.It combines the ground-based GNSS VTEC horizontal change information and the ionospheric model vertical change information to estimate the electron density along the occultation ray path,then calculates the bending angle first-and second-order ionospheric error profiles under the assumption of bilateral local spherical symmetry along the inbound side and outbound side rays.The GNSS RO bending angle first-and second-order ionospheric error profiles was calculated using MetOp-A and GRACE missions observation data and international GNSS service(IGS)GNSS VTEC data from a low solar activity day(i.e.,July 15,2008)and a high solar activity day(i.e.,July 15,2013).The comparative analysis shows that the empirical model consistent with the theoretical model in terms of the second-order Residual Ionospheric Error(RIE)and with the observation data in terms of the first-and second-order bending angle ionospheric errors.Therefore,this method can be used for those RO events with low quality L2 observations and even loss of L2 signal,to correct the first-and second-order ionospheric errors to improve the bending angle accuracy and the RO observations utilization.

关 键 词：GNSS大气掩星 弯曲角 电离层误差 地基GNSS VTEC 

分 类 号：P407[天文地球—大气科学及气象学]