GNSS Compare

The purpose of GNSS Compare is to make the life of developers and researchers easier. It’s an easy to use and easy to extend Android-based framework for calculating the Position, Velocity and Time (PVT) based on the raw GNSS measurements.

GNSS Compare is the winning Android application developed by the Galfins Team (https://gnss-compare.readthedocs.io/en/latest/team.html) as part of the internal European Space Agency (ESA) competition called Galileo Smartphone App Challenge introduced in October 2017. Furthermore, the competition was supported by the European Commission (EC) and European GNSS Agency (GSA). The Challenge was about creating a smartphone application, which will allow the user to choose which satellite constellation to use for Position, Velocity, and Time (PVT) estimation. The aim was to increase the awareness about the European Union’s Galileo satellite navigation programme and also to allow users from common public to view and use Galileo signals.

The current features of GNSS Compare include:
- Open-source code on github: https://github.com/TheGalfins/GNSS_Compare
- Online documentation: https://gnss-compare.readthedocs.io
- Modular software framework for extending GNSS Compare’s PVT algorithms
- Supported GNSS constellations: Galileo only, GPS only, Galileo&GPS combined
- Support for dual-frequency receivers
- Available PVT estimators: Weighted Least Squares, Extended Kalman Filter
- Data logging formats: Simple Logger (UTC timestamp, X, Y, Z), NMEA (UTC timestamp, lat, lon, alt, CN0), Raw GNSS measurements (Google’s GnssLogger format)
- note: all calculations are initialized with phone's FINE location

Please note that for this application to work properly, your phone needs to support both the Galileo Satellite System and Android raw GNSS measurements.
The list of Galileo compatible phones can be found here: https://www.usegalileo.eu/EN/inner.html#data=smartphone.
The list of phones supporting Android raw GNSS measurements can be found here: https://developer.android.com/guide/topics/sensors/gnss.

So far we’ve been testing the application on:
- Samsung Galaxy S8
- Samsung Galaxy S8+
- Xiaomi MI8
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Acknowledgements:
GNSS Compare’s developers would like to thank the European Space Agency for the continuous support throughout the development of this application. Especially we would like to mention the ESA employees that shared their experience and knowledge regarding the Dual-Frequency aspects: Paolo Crosta, Nityaporn Sirikan, Gaetano Galluzzo, Paolo Zoccarato, and Tim Watterton.