Elisa Maria Alessi (Universita di Pisa): Orbit determination and parameter estimation for the radioscience experiments of the BepiColombo mission

The BepiColombo mission to Mercury is an
ESA/JAXA joint project with very challenging objectives
regarding geodesy, geophysics and fundamental physics. The
Celestial Mechanics Group of the University of Pisa is
responsible for the orbit determination of the Mercury
Planetary Orbiter (MPO) and the parameter estimation
corresponding to the radio science experiments. With this,
we mean the gravimetry, rotation and relativity experiments
based on very accurate range and range-rate observations. In
this talk, we will describe the experiment and explain how
the orbit determination is performed. In particular, we
apply a non linear least squares differential correction fit
on a set of observational arcs separated by intervals of
time where the MPO is not visible. The constrained
multi-arc strategy is able to link subsequent arcs in a
smooth way, to solve for variables belonging or not to the
tracking intervals and mitigate problems due to degeneracies
or modeling limitations.