Bernese GPS Software Version 5.0 - Bernese GNSS Software

Table 2.7: Errors in baseline components due to orbit errors.
Orbit Error Baseline Length Baseline Error Baseline Error
in ppm in mm
2.5 m 1 km .1 ppm - mm
2.5 m 10 km .1 ppm 1 mm
2.5 m 100 km .1 ppm 10 mm
2.5 m 1000 km .1 ppm 100 mm
.05 m 1 km .002 ppm - mm
.05 m 10 km .002 ppm - mm
.05 m 100 km .002 ppm .2 mm
.05 m 1000 km .002 ppm 2 mm
2.2 GNSS Satellite Orbits
Table 2.7 gives the actual baseline errors in meters and in parts per million (ppm) for
different baseline lengths and different orbit qualities as they have to be expected based on
Eqn. (2.6). What orbits are available today? Let us mention seven types of orbits, namely
Broadcast Orbits, CODE Ultra Rapid Orbits, CODE Rapid Orbits, CODE Final Orbits,
IGS Ultra Rapid Orbits, IGS Rapid Orbits, and IGS Final Orbits. From these, currently only
the CODE products contain GLONASS orbits. The estimated accuracies, based on analyses
performed by the IGS Analysis Center Coordinator, are given in Table 2.8. The numbers
quoted in Table 2.8 are conservative numbers. The consistency between the contributions
of the best IGS Analysis Centers, including CODE, is of the order of 2 cm for the IGS Final
Orbits, 3 cm for the IGS Rapid Orbits. The comparison between the predicted first 12 hours
of the IGS Ultra Rapid Orbits with the IGS Rapid Orbits is for most satellites regularly of
the order of 5 cm (available for real-time and near real-time applications!). The GLONASS
precise orbits contained in the CODE rapid and final products have a quality below 10 cm.
Table 2.8: Estimated quality of orbits in 2003.
Orbit Type Quality Delay of Availability Available at
Broadcast Orbits ∼2 m Real-time Broadcast message
CODE Ultra Rapid Orbits