GPS Solutions

, Volume 21, Issue 1, pp 43–52 | Cite as

High-rate clock variations of the Galileo IOV-1/2 satellites and their impact on carrier tracking by geodetic receivers

  • O. MontenbruckEmail author
  • A. Hauschild
  • S. Häberling
  • B. Braun
  • G. Katsigianni
  • U. Hugentobler
Original Article


The carrier signals of the first two Galileo satellites, IOV-1 and IOV-2, exhibit subtle phase variations, which may cause high-rate oscillations in carrier phase measurements of geodetic-grade receivers as well as associated Doppler measurement errors. The carrier phase oscillations slightly exceed the noise level of the measurements and have been attributed to a subtle cross talk of signals from two active atomic frequency standards in the clock monitoring and control unit (CMCU). This cross talk is only present in the first two IOV satellites, and its practical implications have partly been compensated by now through a suitable configuration of the CMCU. Nevertheless, a proper understanding of the phenomenon is deemed relevant to the interpretation of Galileo IOV measurements collected with global ground networks in the 2012 to early 2015 time frame. Also, the data collected so far offer valuable insight into the tracking of high-frequency signal variation of geodetic receivers that are of interest for applications such as structural monitoring or earthquake research. We present practical measurements from zero-baseline tests of common geodetic receivers with data rates of 1/30–1 Hz as well as dedicated tests with high-rate (50–100 Hz) receivers to evidence the phenomenon. Efforts are made to understand the different response of specific receivers based on generic receiver tracking and measurement generation concepts.


Galileo Clock oscillation CMCU 



Individual receivers used in this study have been contributed by the DLR Institute of Communication and Navigation as well as Leica Geosystems. The support of both institutions is gratefully acknowledged. Furthermore, the authors would like to thank Dr. Francisco Javier Gonzalez Martinez of ESA/ESTEC for valuable technical comments and his thorough review of an initial manuscript version.


  1. Borio D, Gioia C, Mitchison N (2015) Identifying a low-frequency Oscillation in Galileo IOV pseudorange rates. GPS Solut. doi: 10.1007/s10291-015-0443-7 Google Scholar
  2. Carrillo FJM, Sanchez AA, Alonso LB (2005) Hybrid synthesizers in space: Galileo’s CMCU. In: Proceedings of 2nd international conference on recent advances in space technologies, IEEE, pp 361–368Google Scholar
  3. Felbach D, Heimbuerger D, Herre P, Rastetter P (2003) Galileo payload 10.23 MHz master clock generation with a clock monitoring and control unit (CMCU). In: Proceedings of IEEE 2003 frequency control symposium and 17th European frequency and time forum, pp 583–586. doi: 10.1109/FREQ.2003.1275156
  4. Felbach D, Soualle F, Stopfkuchen L, Zenzinger A (2010) Clock monitoring and control units for navigation satellites. In: Proceedings of IEEE 2010 frequency control symposium (FCS), IEEE, pp 474–479. doi: 10.1109/FREQ.2010.5556283
  5. Gonzalez F, Waller P (2007) Short term GNSS clock characterization using one-way carrier phase. In: IEEE international FCS 2007 and 21st EFTF, pp 517–522. doi: 10.1109/FREQ.2007.4319127
  6. Griggs E, Kursinski E, Akos D (2015) Short-term GNSS satellite clock stability. Radio Sci 50(8):813–826. doi: 10.1002/2015RS005667 CrossRefGoogle Scholar
  7. Häberling S, Rothacher M, Zhang Y, Clinton JF, Geiger A (2015) Assessment of high-rate GPS using a single-axis shake table. J Geodesy 89(7):697–709. doi: 10.1007/s00190-015-0808-2 CrossRefGoogle Scholar
  8. Hauschild A, Montenbruck O, Steigenberger P (2013) Short-term analysis of GNSS clocks. GPS Solut 17(3):295–307. doi: 10.1007/s10291-012-0278-4 CrossRefGoogle Scholar
  9. Katsigianni G (2015) Zero-baseline analysis of Galileo data from multi-GNSS experiment. Master’s Thesis, Technische Universität MünchenGoogle Scholar
  10. Montenbruck O, Steigenberger P, Khachikyan R, Weber G, Langley RB, Mervart L, Hugentobler U (2014) IGSMGEX: preparing the ground for multi-constellation GNSS science. Inside GNSS 9(1):42–49Google Scholar
  11. Moschas F, Stiros S (2014) PLL bandwidth and noise in 100 Hz GPS measurements. GPS Solut 19(2):173–185. doi: 10.1007/s10291-014-0378-4 CrossRefGoogle Scholar
  12. Odijk D, Teunissen PJ (2013) Estimation of differential inter-system biases between the overlapping frequencies of GPS, Galileo, BeiDou and QZSS. In: 4th international colloquium scientific and fundamental aspects of the Galileo programme, pp 1–8, 4–6 December 2013, PragueGoogle Scholar
  13. Paziewski J, Wielgosz P (2015) Accounting for Galileo-GPS inter-system biases in precise satellite positioning. J Geodesy 89(1):81–93. doi: 10.1007/s00190-014-0763-3 CrossRefGoogle Scholar
  14. Ward PW, Betz JW, Hegarty CJ (2006) Satellite signal acquisition, tracking, and data demodulation. In: Kaplan ED (ed) Understanding GPS—principles and applications, chap 5. Artech House, Boston, pp 174–175Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • O. Montenbruck
    • 1
    Email author
  • A. Hauschild
    • 1
  • S. Häberling
    • 2
  • B. Braun
    • 1
  • G. Katsigianni
    • 3
  • U. Hugentobler
    • 3
  1. 1.Deutsches Zentrum für Luft- und RaumfahrtGerman Space Operations CenterOberpfaffenhofenGermany
  2. 2.Eidgenössische Technische HochschuleInstitut für Geodäsie und PhotogrammetrieZurichSwitzerland
  3. 3.Technische Universität MünchenInst. für Astronomische und Physikalische GeodäsieMunichGermany

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