The first Galileo FOC satellites: From useless to essential

In August 2014, the European Global Navigation Satellite System Galileo successfully completes its In-Orbit Validation phase and the first two Full Operational Capability satellites were launched. Currently (February 2015), Galileo consists of four IOV satellites and two FOC ones, but only three IOVs and one FOC are working correctly. The two FOCs were injected in a not nominal orbit; at the time of this study only one of them (specifically FOC-FM1) was shifted into a more circular orbit. However, several studies and analysis were carried out by ESA to monitor the impact on the health status of the FOC satellites in wrong elliptical orbits. This paper investigates the potential improvements on constellation geometry provided by the inclusion of the FOCs and analyzes Galileo single-point positioning performance. Different methods for satellite position are considered due to the lack of navigation messages.