Common-clock GPS single differences

An improved correlation model for GPS phase observations based on turbulence theory

authored by
Gaël Kermarrec, Steffen Schön

Microwave signals, for example, those from Global Navigation Satellite System (GNSS) and Very Long Baseline Interferometry (VLBI), are affected by tropospheric turbulence in such a way that the random fluctuations of the atmospheric index of refractivity correlate the phase measurements. A proper modeling of correlations is mandatory to avoid biased analysis, particularly when statistical tests are used. In this contribution, we analyze single differences (SD) computed from Global Positioning System (GPS) phase observations for which the between receiver clock error could be strongly mitigated by a specific common clock setting. We estimate specific parameters from the power spectral density (psd), which is directly related to the correlation function, with the debiased Whittle maximum likelihood and investigate their dependencies with the satellite geometry (elevation, azimuth angles) and the time of the day. We show that (i) the estimated slopes of the psd follow the one predicted by the Kolmogorov turbulence theory and (ii) the cut-off at high frequencies shows daily variations that may be linked with the strength of the turbulence. Based on these findings, we derive an improved spectral density model for GPS phase SD. The results of this study contribute to improving the stochastic description of random effects impacting VLBI and GNSS phase observations by studying variations of parameters from the von Karman spectrum.

Institute of Meteorology and Climatology
Institute of Geodesy
CRC 1464: Relativistic and Quantum-Based Geodesy (TerraQ)
Advances in space research
No. of pages
Publication date
Publication status
Peer reviewed
ASJC Scopus subject areas
Aerospace Engineering, Astronomy and Astrophysics, Geophysics, Atmospheric Science, Space and Planetary Science, Earth and Planetary Sciences(all)
Research Area (based on ÖFOS 2012)
Astronomy, Probability theory
Sustainable Development Goals
SDG 9 - Industry, Innovation, and Infrastructure
Electronic version(s) (Access: Open)