Simple Methods for the Estimation of the Short-Term Stability of GNSS On-Board Clocks
CENTRE NATIONAL D'ETUDES SPATIALES TOULOUSE (FRANCE)
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The estimation of GNSS on-board clocks behavior is generally a complex task requiring a large ground infrastructure a global network of ground stations and an intense computation the so-called ODTS, Orbit Determination and Time Synchronization. Here, we propose two alternative methods that allow one to easily estimate the short-term stability of GNSS on-board clocks with respect to a given ground station on a pass. In the first method, we simply consider the phase measurements of the RINEX observation files provided by the ground station on which we apply a high-order polynomial fitting. Thus, we keep the high-frequency part of the measurement, which is expected to be representative of the clock difference. In the second method, we carry out a residuals computation on a given pass using precise ephemerides. The ground station phase measurements are considered. We compute the transmission dates and the satellites position by interpolation of these dates. Then we compute the theoretical pseudo-distance using the satellites position and the measurements the vertical troposphere delay is adjusted.
- Operations Research
- Test Facilities, Equipment and Methods