Low-Earth spacecraft orbits are usually computed from onboard measurements of pseudorange, carrier
phase and Doppler signals from one or more constellations of global navigation satellite systems (GNSS),
including Galileo, GPS, Beidou and Glonass. The high accuracy of these measurements together with high
accuracy of the environmental and force models used to propagate satellite orbits and the availability of
system biases corrections through third party services is currently stimulating research and applications to
achieve unprecedented accuracy in the determination of satellite orbits in real time.
The topic of this thesis is the development of a precise orbit determination filter for low-Earth orbit (LEO)
satellites making use of multi-frequency, multi-constellation, GNSS measurements. The reference missions
will be the Sentinels’ missions, which are the Earth Observation missions of ESA’s Copernicus program. The
student will concentrate on the architecture of one or more filter designs (e.g., batch, Kalman, smoother,
particle, …) making use of current ancillary libraries embodying the capabilities to model the force field and
the space-time reference frames.
The goal is to achieve a consistent determination of the LEO satellite position with a precision of a few
centimeters through the optimization of the computational procedure and a revision of the implementation of
the algorithms (force modeling, numerical integration, matrix operations, etc.) to make use of parallelization
techniques, possibly including the use of GPU’s. The target platforms are an HPC multi-processor system
and a high performance laptop.
Interested students should contact prof. S. Casotto at stefano.casotto@unipd.it