Ionospheric delay correction is the core issue of LEO satellite single-frequency precise orbit determination. At present, "the method of ionosphere scale factor" is mainly adopted in the LEO satellite ionospheric delay correction, but the method doesn't consider the electron density peak height along with the variation of factors, such as latitude and longitude, day and night, seasons, solar activity, etc. IRI2012 model while considering the influence of the above factors on the electron density peak height, but because of the height criteria inconsistent with ionosphere single layer model, there is usually a systematic deviation and can't be used directly. Therefore, this paper puts forward to an improved ionospheric delay correction method, the ionosphere thin layer height as the constraint condition of IRI2012 model of electron density peak height of the mean parameter estimation. Based on Swarm satellite single-frequency observation data, the effectiveness of the method was verified. The results showed that: with the improved model of the ionosphere, the precision of Swarm satellite obit radial, tangential and normal was improved in varying degrees, especially for the radial and normal most obviously, improved on average by 31.6% and 32.0%, respectively. At the same time, the systemic deviation of the orbit reduced significantly, especially for the radial and normal, reduced on average by 65.0% and 54.7%, respectively.
[1] 谢世杰, 鲁和平. GPS接收机性能之我见[J]. 测绘通报, 2000(12):32-34. XIE Shijie, LU Heping. My Viewpoint of GPS Receiver Performance[J]. Bulletin of Surveying and Mapping, 2000(12):32-34.
[2] MONTENBRUCK O. Kinematic GPS Positioning of LEO Satellites Using Ionosphere-free Single Frequency Measurements[J]. Aerospace Science and Technology, 2003, 7(5):396-405.
[3] BOCK H, JÄGGI A, DACH R, et al. GPS Single-frequency Orbit Determination for Low Earth Orbiting Satellites[J]. Advances in Space Research, 2009, 43(5):783-791.
[4] 胡国荣, 欧吉坤, 崔伟宏. 星载单频GPS接收机低轨卫星几何法定轨研究[J]. 天文学报, 2000, 41(3):278-288. HU Guorong, OU Jikun, CUI Weihong. A Research on Geometric Orbit Determination for GPS-based Single-frequency Receivers Aboard Low Earth Satellites[J]. Acta Astronomica Sinica, 2000, 41(3):278-288.
[5] 刘洋, 易东云, 王正明. 基于单频GPS接收机的低轨卫星准实时定轨算法研究[J]. 航天控制, 2005, 23(4):32-34, 40. LIU Yang, YI Dongyun, WANG Zhengming. The Algorithm Research of Norm-real-time Orbit Determination of LEO Satellites Based on Single-frequency GPS Receiver[J]. Aerospace Control, 2005, 23(4):32-34, 40.
[6] 郭向, 张强, 赵齐乐, 等. 基于单频星载GPS数据的低轨卫星精密定轨[J]. 中国空间科学技术, 2013, 33(2):41-46. GUO Xiang, ZHANG Qiang, ZHAO Qile, et al. Precise Orbit Determination for LEO Satellites Using Single-frequency GPS Observations[J]. Chinese Space Science and Technology, 2013, 33(2):41-46.
[7] 张小红, 李星星, 郭斐, 等. GPS单频精密单点定位软件实现与精度分析[J]. 武汉大学学报(信息科学版), 2008, 33(8):783-787. ZHANG Xiaohong, LI Xingxing, GUO Fei, et al. Realization and Precision Analysis of Single-frequency Precise Point Positioning Software[J]. Geomatics and Information Science of Wuhan University, 2008, 33(8):783-787.
[8] 涂锐, 黄观文, 凌晴. GPS单频精密单点定位的研究实现[J]. 测绘科学, 2011, 36(3):68-69. TU Rui, HUANG Guanwen, LING Qing. Precise Point Positioning of GPS Single frequency[J]. Science of Surveying and Mapping, 2011, 36(3):68-69.
[9] 姜卫平, 邹璇, 唐卫明. 基于CORS网络的单频GPS实时精密单点定位新方法[J]. 地球物理学报, 2012, 55(5):1549-1556. JIANG Weiping, ZOU Xuan, TANG Weiming. A New Kind of Real-time PPP Method for GPS Single Frequency Receiver Using CORS Network[J]. Chinese Journal of Geophysics, 2012, 55(5):1549-1556.
[10] 阮仁桂, 吴显兵, 冯来平, 等. 同时估计电离层延迟的单频精密单点定位方法[J]. 测绘学报, 2012, 41(4):490-495. RUAN Rengui, WU Xianbing, FENG Laiping, et al. Single-frequency Precise Point Positioning with Simultaneous Ionospheric Delay Estimation[J]. Acta Geodaetica et Cartographica Sinica, 2012, 41(4):490-495.
[11] MONTENBRUCK O, GILL E. Ionospheric Correction for GPS Tracking of LEO Satellites[J]. The Journal of Navigation, 2002, 55(2):293-304.
[12] BILITZA D, REINISCH B W. International Reference Ionosphere 2007:Improvements and New Parameters[J]. Advances in Space Research, 2008, 42(4):599-609.
[13] 郑磊, 李征航, 刘万科. 用星载单频GPS数据实时定轨的电离层延迟改正[J]. 大地测量与地球动力学, 2010, 30(3):118-121. ZHENG Lei, LI Zhenghang, LIU Wanke. Correction of Ionospheric Delay for Real-time Orbit Determination by Using On-board Single-frequency GPS Data[J]. Journal of Geodesy and Geodynamics, 2010, 30(3):118-121.
[14] 屈小川, 李征航, 龚晓颖. 星载单频GPS数据的电离层延迟改正方法分析[J]. 北京航空航天大学学报, 2012, 38(2):252-256. QU Xiaochuan, LI Zhenghang, GONG Xiaoying. Analysis on Ionospheric Delay Correction Method of Space-borne Single-frequency GPS Data[J]. Journal of Beijing University of Aeronautics and Astronautics, 2012, 38(2):252-256.
[15] 温晋, 万卫星, 丁锋, 等. 电离层垂直TEC映射函数的实验观测与统计特性[J]. 地球物理学报, 2010, 53(1):22-29. WEN Jin, WAN Weixing, DING Feng, et al. Experimental Observation and Statistical Analysis of the Vertical TEC Mapping Function[J]. Journal of Geophysics, 2010, 53(1):22-29.
[16] BILITZA D, ALTADILL D, ZHANG Yongliang, et al. The International Reference Ionosphere 2012-A Model of International Collaboration[J]. Journal of Space Weather and Space Climate, 2014, 4:A07.
[17] KLEUSBERG A, TEUNISSEN P J G. GPS for Geodesy[M]. Berlin:Springer, 1996.
[18] BILITZA D, MCKINNELL L A, REINISCH B, et al. The International Reference Ionosphere Today and in the Future[J]. Journal of Geodesy, 2011, 85(12):909-920.
[19] BILITZA D. International Reference Ionosphere (1990)[J]. Planetary and Space Science, 1992, 40(4):544.
[20] VAN DEN IJSSEL J, ENCARNAÇÃO J, DOORNBOS E, et al. Precise Science Orbits for the Swarm Satellite Constellation[J]. Advances in Space Research, 2015, 56(6):1042-1055.
[21] 田英国, 郝金明, 刘伟平, 等. 星载GNSS低轨卫星精密定轨快速解算方法[J]. 大地测量与地球动力学, 2014, 34(1):157-160. TIAN Yingguo, HAO Jinming, LIU Weiping, et al. A Rapid Solution Method on Precise Orbit Determination of LEOs Using GNSS[J]. Journal of Geodesy and Geodynamics, 2014, 34(1):157-160.
[22] Swarm Expert Support Laboratories. Swarm L2 TEC Product Description (SW-TR-GFZ-GS-0007)[EB/OL]. (2014-08-27)[2014-11-20]. https://earth.esa.int/documents/10174/1514862/Swarm_Level-2_TEC_Product_Description.
