Galileo: following the trail of the dragon-ships
First Galileo maritime trials outside mainland Europe.
Belgian frigate Leopold I-F930
Results are being processed from the first Galileo maritime trials outside mainland Europe. The long-range, high-latitude testing spanned the North Sea, following the same historical sailing route that Viking dragon-ships used 1200 years ago.
Ancient manuscripts record Viking navigators relied on ‘sunstones’ to find their way – modern archaeologists believe these may have been polarising crystals to pinpoint the Sun even in overcast skies.
By contrast, Belgian frigate Leopold I-F930, participating in the end-of-year trials, carried the most up-to-date equipment possible, with multiple Galileo receivers for both its publicly-available Open Service and secure Public Regulated Service.
Miguel Manteiga Bautista, head of ESA’s GNSS (Global Navigation Satellite System) Security Office, explains:
Galileo is currently in a transition between its In-Orbit Validation phase and follow-on Full Operational Capability phase.
This means we are actively engaging in all kinds of experimental demonstrations of all Galileo services, in particular the Public Regulated Service, which offers the most highly accurate positioning and timing performance, but with access strictly restricted to authorised users.
Belgian frigate Leopold I-F930
The frigate sailed first from the Dutch marine base of Den Helder on 4 December 2013 to Stavanger in Norway. From there it progressed north in very rough seas with 10-m high waves, coming close to the Arctic circle on 17 December – a first for Galileo PRS observations – before heading homeward.
The testing provided tangible in-situ evidence of Galileo signal stability across both its operating frequencies up at high latitudes, equalling low satellite elevations in the local sky.
Following the completion of earlier road and flight testing last summer and autumn, the last challenge for Galileo’s IOV phase was to engage in a long-term maritime trial into high latitudes.
The testing was performed as part of the ‘PRS Participants to IOV” (PPTI) project jointly managed by ESA and the European Commission, in collaboration with the European GNSS Office Agency and several Member States possessing PRS test receiver technology.
The trials were performed by the Royal Military Academy (RMA) of the Belgian Ministry of Defence, the UK Space Agency in collaboration with satnav-specialising company Nottingham Scientific Ltd (NSL) and ESA, serving to ensure PRS signals were available whenever the four Galileo satellites currently in orbit came into view.
A dual test setup was fitted to the frigate at Den Helder:
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Belgium connected a PRS receiver and an Open Service receiver, both manufactured in Belgium by Septentrio NV, to a common antenna. The PRS receiver recorded raw PRS measurements on both frequencies while the Open Service receiver logged data from openly-available Galileo, GPS and Glonass signals at one second intervals
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the UK’s NSL installed its ULTRA system configured to record radio frequency samples, allowing the detailed post-processing of Galileo OS and PRS signals
Dr David Parker, Chief Executive of the UK Space Agency comments:
This test represents a significant milestone on the road to demonstrating early PRS capability across a range of platforms.
It should serve as a model for wider international collaboration between national governments and industry to prove and demonstrate PRS in different applications.
Mark Dumville, NSL General Manager adds:
This activity represents a truly collaborative effort at all levels. The trial involved UK and Belgian governments and industry partners with support from different European bodies as well as officials from the Netherlands and Norway.
This team effort has enabled the concept of RF sampling processing of Galileo PRS signals to be tested in real-world operational environments. We have confirmed that the prototype receiver is now ready to support European governments and associated PRS applications.
Results from the trial will guide future Galileo developments for years to come.