基于BDS/GPS双系统的全球电离层建模  

Global ionosphere model based on BDS/GPS dual-system observations

作　　者：薛军琛[1] 宋淑丽[1] 朱文耀[1] 

机构地区：[1]中国科学院上海天文台,上海200030

出　　处：《中国科学：物理学、力学、天文学》2015年第7期23-32,共10页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金资助项目(批准号:10603011;11273048)

摘　　要：借助当前比较完善的GPS系统,建立基于BDS/GPS双系统的全球电离层模型,是克服BDS单系统建模弊端,提高全球电离层模型和硬件延迟(DCB)监测精度的一种有效途径.本文分析了基于BDS/GPS双系统的电离层模型所能达到的精度,以及GPS观测对DCB监测的辅助作用.文中选用了太阳活动峰年2013年2月11日–2014年1月13日336天的BDS/GPS双系统观测资料,利用15×15阶球谐函数模型建立了全球电离层模型(GIM/SHA),并利用IGS最终电离层产品(GIM/IGS)、双频实测VTEC和海洋测高数据对该双系统模型的电离层产品进行了全面的精度评估.结果表明:(1)通过与三种基准数据比对,GIM/SHA的外符合精度在3–6 tecu范围内,且系统性偏差较小;(2)GPS卫星P1P2频点DCB与IGS最终产品结果比较BIAS在0.1 ns内,RMS最大不超过0.2 ns;(3)通过比较BDS单系统与双系统生成的卫星和接收机B1B2频点DCB发现,两种方法解算的DCB均值差别为0.01–0.227 ns,双系统解算BDS卫星DCB稳定性稍优于单系统结果,但是GPS观测资料的加入能够明显地提高接收机DCB的稳定性;从14颗BDS在轨卫星B1B2频点DCB长期稳定性统计可见,各卫星DCB长期稳定性为0.2–0.3ns,其中GEO卫星稳定性水平稍差.In order to overcome the weakness of GIM based on BeiDou single system and improve the accuracy of GIM and differential code bias （DCB）, we created the GIM products based on BDS/GPS dual system assisted with GPS. In this study, we do analysis on the accuracy of GIM based on BDS/GPS and the auxiliary function for DCB monitoring by GPS. The ionosphere observations of BeiDou and GPS over 336 d from February 11, 2013 to January 13, 2014 in solar high activity have been used to generate a set of global ionosphere grids （GIM/SHA） with sphere harmonics at spatial resolution of 15×15 degree and order. The comprehensive accuracy assessment for the GIM/SHA products is provided by using IGS final products （GIM/IGS）, real-measured vertical total electron content （VTEC） by dual-frequency observations and VTEC by Jason-2 radar altimetry. Our study reveals： （1） Comparing the VTEC on global grids with that of three kinds of assessment data, the average RMS of GIM/SHA is in the range of 3-6 tecu with a little systematic bias; （2） For the estimated P1P2 DCB of GPS satellites, the bias between GIM/SHA and IGS is within 0.1 ns with RMS less than 0.2 ns; （3） For the estimated B1B2 DCB of satellites and receivers based on BeiDou single system and dual system, the difference of mean values is within 0.01-0.227 ns and the solution based on the dual system is a little better than that based on the single system, but GIM/SHA can obviously improve the stability for receiver DCB by using GPS observations. From the long-term stability statistics for 14 BeiDou satellites＇ B1B2 DCB, the stability is at 0.2-0.3 ns level, while slightly worse for that of GEt satellites.

关 键 词：全球电离层模型 GPS BDS IGS 垂直电子总含量 硬件延迟 

分 类 号：P228.4[天文地球—大地测量学与测量工程]