GPS Solutions

, Volume 15, Issue 2, pp 129–137 | Cite as

GOCE orbit predictions for SLR tracking

Original Article


After a descent phase of about half a year, the Gravity field and steady-state Ocean Circulation Explorer (GOCE) reached the final orbital altitude of the first measurement and operational phase (MOP-1) in September 2009. Due to this very low orbital altitude and the inactive drag compensation during descent, the generation of reliable predictions of the GOCE trajectory turned out to be a major challenge even for short prediction intervals. As predictions of good quality are a prerequisite for frequent ranging from the tracking network of the International Laser Ranging Service (ILRS), Satellite Laser Ranging (SLR) data of GOCE was very sparse at mission start and made it difficult to independently calibrate and optimize the orbit determination based on data of the Global Positioning System (GPS). In addition to the GOCE orbit predictions provided by the European Space Agency (ESA), the Astronomical Institute of the University of Bern (AIUB) started providing predictions on July 22, 2009, as part of the Level 1b to Level 2 data processing performed at AIUB. The predictions based on the 12-h ultra-rapid products of the International GNSS Service (IGS) were originally intended to primarily serve the daylight passes in the early evening hours over Europe. The corresponding along-track prediction errors were often kept below 50 m during the descent phase and allowed for the first successful SLR tracking of GOCE over Europe on July 29, 2009, by the Zimmerwald observatory. Additional predictions based on the IGS 18-h ultra-rapid products are provided by AIUB since September 20, 2009, to further optimize the GOCE SLR tracking. In this article, the development of the GOCE prediction service at AIUB is presented, and the quality of the orbit predictions is assessed for periods with and without active drag compensation. The prediction quality is discussed as a function of the prediction interval, the quality of the input products for the GPS satellite orbits and clocks, and the availability of the GOCE GPS data. From the methodological point of view, different approaches for the treatment of the non-gravitational accelerations acting on the GOCE satellite are discussed and their impact on the prediction quality is assessed, in particular during the descent phase. Eventually, an outlook is given on the significance of GOCE SLR tracking to identify systematic errors in the GPS-based orbit determination, e.g., cross-track errors induced by mismodeled GOCE GPS phase center variations (PCVs).


GOCE Orbit prediction Non-gravitational accelerations Drag-free flight GPS SLR 


  1. Bock H, Jäggi A, Švehla D, Beutler G, Hugentobler U, Visser P (2007) Precise orbit determination for the GOCE satellite using GPS. Adv Space Res 39(10):1638–1647. doi:10.1016/j.asr.2007.02.053 CrossRefGoogle Scholar
  2. Bock H, Dach R, Jäggi A, Beutler G (2009) High-rate GPS clock corrections from CODE: support of 1 Hz applications. J Geod 83(11):1083–1094. doi:10.1007/s00190-009-0326-1 CrossRefGoogle Scholar
  3. Dach R, Hugentobler U, Fridez P, Meindl M (eds) (2007) Bernese GPS Software Version 5.0. Documentation. Astronomical Institute, University of Bern, BernGoogle Scholar
  4. Dach R, Brockmann E, Schaer S, Beutler G, Meindl M, Prange L, Bock H, Jäggi A, Ostini L (2009) GNSS processing at CODE: status report. J Geod 83(3–4):353–365. doi:10.1007/s00190-008-0281-2 CrossRefGoogle Scholar
  5. Dow J, Neilan R, Rizos C (2009) The international GNSS service in a changing landscape of global navigation satellite systems. J Geod 83(3–4):191–198. doi:10.1007/s00190-008-0300-3 CrossRefGoogle Scholar
  6. Drinkwater M, Haagmans R, Muzi D, Popescu A, Floberghagen R, Kern M, Fehringer M (2006) The GOCE gravity mission: ESA’s first core explorer. In: 3rd GOCE User Workshop, 6–8 November 2006, Frascati, Italy, pp 1–7, ESA SP-627Google Scholar
  7. GOCE Level 2 Product Data Handbook (2009) GO-MA-HPF-GS-0110, Issue 4.1, European GOCE Gravity Consortium.
  8. Jäggi A, Hugentobler U, Beutler G (2006) Pseudo-stochastic orbit modeling techniques for low-Earth orbiters. J Geod 80(1):47–60. doi:10.1007/s00190-006-0029-9 CrossRefGoogle Scholar
  9. Jäggi A, Dach R, Montenbruck O, Hugentobler U, Bock H, Beutler G (2009) Phase center modeling for LEO GPS receiver antennas and its impact on precise orbit determination. J Geod 83(12):1145–1162CrossRefGoogle Scholar
  10. Johannessen JA, Balmino G, LeProvost C, Rummel R, Sabadini R, Sünkel H, Tscherning CC, Visser P, Woodworth P, Hughes CW, LeGrand P, Sneeuw N, Perosanz F, Aguirre-Martinez M, Rebhan H, Drinkwater MR (2003) The European gravity field and steady-state ocean circulation explorer satellite mission: its impact on geophysics. Surv Geophys 24:339–386. doi:10.1023/B:GEOP.0000004264.04667.5e CrossRefGoogle Scholar
  11. Koop R, Gruber T, Rummel R (2006) The status of the GOCE high-level processing facility. In: 3rd GOCE UserWorkshop, 6-8 November 2006, Frascati, Italy, pp 195-205, ESA SP-627Google Scholar
  12. Pearlman MR, Degnan JJ, Bosworth JM (2002) The International Laser Ranging Service. Adv Space Res 30(2):135–143. doi:10.1016/S0273-1177(02)00277-6 CrossRefGoogle Scholar
  13. Rummel R, Balmino G, Johannessen J, Visser P, Woodworth P (2002) Dedicated gravity field missions–principles and aims. J Geodyn 33:3–20. doi:10.1016/S0264-3707(01)00050-3 CrossRefGoogle Scholar
  14. Schmidt R, Baustert R, König R, Reigber C (2002) Orbit Predictions for CHAMP—development and status. In: Reigber C, Lühr H, Schwintzer P (eds) First CHAMP mission results for gravity, magnetic and atmospheric studies. Springer, Berlin, pp 104–111Google Scholar
  15. Urschl C, Beutler G, Gurtner W, Hugentobler U, Schaer S (2007) Calibrating GNSS orbits with SLR tracking data. In: Proceedings of the 15th ILRSWorkshop, 15–20 October 2006, Canberra, AustraliaGoogle Scholar
  16. Visser PNAM, van den IJssel J, Van Helleputte T, Bock H, Jäggi A, Beutler G, Švehla D, Hugentobler U, Heinze M (2009) Orbit determination for the GOCE satellite. Adv Space Res 43(5):760–768. doi:10.1016/j.asr.2008.09.016 CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Astronomical InstituteUniversity of BernBernSwitzerland
  2. 2.European Space Research Institute, European Space AgencyFrascatiItaly

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