Abstract :
[en] For over a decade, Europe has started to develop its own Global Navigation Satellite System
(GNSS). Initiated in 1999, the Galileo project finally materialized a few years ago, recently
experiencing a prompt expansion with the launch, in 2015 and 2016, of 8 satellites belonging to
the Full Operational Capability (FOC) generation. Broadcasting new signals, with new modulations,
the first studies addressing this system reveal promising level of precisions on both code
and carrier phase observables. Still in test phase but already available for measurements, this
recent system can be used to estimate positions.
Among the new signals developed by the Galileo program, the Galileo E5 AltBOC, also known
as Galileo E5a+b or Galileo E5, reveals great characteristics. Thanks to its particular AltBOC
modulation, it allows more precise code and phase observations besides being less affected by
multipath. These innovative performances should lead to more precise position estimations than
with any other signal presently in use.
In this master thesis, we compared the positions estimated with GPS and Galileo on their
different frequencies (L1, L2, L5 for GPS and E1, E5a, E5b and E5 AltBOC for Galileo). We
combined the observations made by the receivers belonging to the University of Liège (2 Trimble
NetR9 receivers, 1 Septentrio PolaRxS receiver and one Septentrio PolaRx4 receiver) in double
differences (DD) combinations using various configurations (zero baseline (ZB), short baseline
(SB) and medium baseline (MB)).
It turns out that Galileo E5 AltBOC outperforms all other signal in terms of observation precision
(estimated in a DD SB configuration in order to remove atmospheric and clock error
sources affecting the signal). Regarding the precision obtained on the computed positions, we
could reach a few decimetres with Galileo E5 code pseudoranges on baselines up to 25 kilometres.