Quantifying mis-modelling effects in the GNSS yawattitude and phase wind-up

The yaw-attitude modelling of GNSS satellites is a critical objective
underlying the phase wind-up (PWU) correction and orbit determination.
The attitude mis-modelling during the eclipse seasons may lead to a
significant impact in the Precise Point Positioning (PPP), applications with
demanding availability requirements. The current study focuses on the
numerical investigation of the GNSS yaw-attitude model as this has been
implemented into our Analysis Centre Software (ACS) Orbit Determination
and Positioning (ODP) module. We focus on periods during the eclipse and
their impact on the PWU by considering tabulated GNSS precise orbit data.
The present analysis aims at quantifying underlying issues in precise
applications such as the impact of the yaw-angle mis-modelling to the PWU
effect. The yaw-attitude analysis has been performed for daily and annual
time periods. The modelling of the yaw-angle variations over annual periods,
as a function of the β angle during a GNSS draconic year forms a useful
prediction scheme of the GNSS eclipse seasons and the expected impact in
the user’s observations. The current approach has been applied for satellites
included in the GPS Blocks IIA, IIR, IIF and the GLONASS-M series.