Knowledge of the global navigation satellite system (GNSS) satellite clock error is crucial\nin real-time precise point positioning (PPP), seismology, and many other high-rate GNSS\napplications. In this work, the authors show the characterisation of the atomic GNSS clockâ??s stability\nand its dependency on the adopted orbit type using Allan deviation with two methods of averaging\ntime. Four International GNSS Service (IGS) orbit types were used: broadcast, ultra-rapid, rapid and\nfinal orbit. The calculations were made using high-rate 1 Hz observations from the IGS stations\nequipped with external clocks (oscillators). The most stable receiver oscillator was chosen as a\nreference clock. The results show the advantage of the newest GPS satellite block with respect to the\nother satellites. Significant differences in the results based on the orbit type used have not been\nrecorded. Many averaging time methods used in Allan deviation (ADEV) show the clockâ??s\nfluctuations, usually smoothed in 2n s averaging times.
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