Directions 2018: Galileo ascendant

December 8, 2017  - By
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By Paul Verhoef
Director of the Galileo Programme and Navigation-related Activities,
European Space Agency

Paul Verhoef

The European Space Agency (ESA) and the European GNSS Agency (GSA) are starting 2018 with the commissioning and In-Orbit Testing (IOT) of four new Galileo satellites.

This work is fairly routine for us as we have achieved the process successfully many times. But the impact of four new satellites for Galileo services is a different story.

This batch of satellites provided by OHB of Germany — 19, 20, 21 and 22  — will bring our constellation to 22 satellites. Together with the necessary ground segment delivered by Thales Alenia Space (TAS) and Airbus Defense and Space (ADS) and their many subcontractors throughout Europe, this will be providing availability to users anywhere in the world in order to achieve a high-quality position solution 99.8% of the time. “High quality” is hereby meant that the position dilution of precision (PDOP) will be smaller than 5, with our final accuracy for a full 24 FOC satellites operating at full potential being PDOP ~ 2.4.

This achievement will create a step change in the ability of service providers and equipment manufacturers to utilize the Galileo service. For all intents and purposes, it means the Galileo signal can always be relied upon to be there, and industry can sell products and design the power budget of devices based upon that fact.

Dual Frequency. The first mass-market GNSS receiver chip for smartphones and mobile devices that is able to utilize dual-frequency Galileo signals was released by Broadcom in September, able to employ both L1/E1 and L5/E5 signals. In 2018, dual-frequency technology like this will provide an order of magnitude increase in the performance of mobile device location-based services (LBS), especially in urban environments, and Broadcom advertises a 50% reduction in power consumption. The world of mobile-device LBS is going to change in 2018, and it will be due to the availability of Galileo.

It will not be the first time the partnership of ESA, the European Commission (EC) and the GSA has made a service available that has changed the nature of the marketplace. The GSA already has in service the ESA-designed EGNOS LPV200 aircraft approach service performing so well that countries like France have taken the decision to phase out the terrestrial Instrument Landing System that has burdened the capital expenditure budgets of airports in the past.

We have had discussions with several commercial organizations that are interested in building products around Galileo, and I am excited to see what they are going to come up with. With Galileo Initial Services the world had a new navigation signal to study and trial. In 2018 the world will have a new star to navigate by — well, a new constellation of 22 to 24 stars, I should say!

FOC. In the summer of 2018 we will launch the final part of the Galileo FOC constellation (geometrically speaking) with four more satellites taking us beyond the 24 needed for 100% coverage and minimum performance limitation from satellite geometry. The launch will also provide our first in-orbit spares, enabling us to plan for the end of life of our old validation phase satellites or otherwise supplement the constellation to improve performance.

What might we do with these in-orbit spares? Our first priority is to complete a constellation of 24 satellites in the correct orbits for minimum PDOP; as you know, a Fregat upper-stage malfunction left GSAT 0201 and 0202 in orbits too elliptical to correct fully, so the current plan is to complete the 24-satellite geometry. 0201 and 0202 are foreseen to be fully integrated in the Galileo operational system in 2018 following further testing and preparations, allowing us to have a 24+2 constellation with “hot back-up” from 0201 and 0202 contributing at around current GPS satellite levels of accuracy.


“It will not be the first — nor the last — time the partnership of ESA, the EC and the GSA has made a service available that has changed the nature of the marketplace.”


Of course, as is known to the community, the validation-phase satellite GSAT 0104 is down to single frequency, and we routinely monitor the health of all satellites. 0104 is the only satellite that has lost part of its function; designed-in redundancy has managed all other problems.

However, obviously we will be examining all options for deployment to ensure that the Galileo schedule is not impacted by in-orbit failures, and those we have experienced we have learned from and mitigated successfully without impacting the service.

The first two spares are not the end of our ability to maintain the constellation and our system performance. All four validation phase satellites will need to be replaced, and so the “Batch 3” satellite procurement will continue to regularly roll out satellites for replenishment of the constellation.

Enhancements. That won’t mean we will be resting on our laurels. In 2018 we also plan to release enhancements to the ground segment for Galileo, a process that will be a first as the system is already being operated by the GSA.

The process of managing an in-service upgrade program with the GSA is going to be new and challenging, but we have a strong engineering support team deployed as part of our working arrangement with the GSA to help ensure the process goes smoothly.

Of course, the need for GSA to be able to continue smooth operations imposes extra discipline and imposes on us a balance between stable operations and continued build-out of the infrastructure. We do not consider this to be a problem; on the contrary, the focus will be on robust operations and availability to the user.

Back at base (ESTEC in the Netherlands for Galileo and Toulouse, France, for EGNOS) we are full steam ahead on preparing the future. We are moving forward at considerable pace with our next-generation designs that develop new functionality for continuous service improvements.

Free PPP. Galileo was designed to broadcast a Commercial Service signal providing services such as precise point positioning to paying customers, but we are pleased to able to report that the EC has confirmed that this service will be provided for free by the European Union. In 2018/2019 the GSA will select the providers and get that unique, free service on the air.

In 2017 the EC confirmed the decision to implement the commercial service using E6-B with both encrypted and open components so all users could benefit for all frequency bands. Now, with the decision to make the service available free of charge, all users of Galileo, with the right type of receiver, will be able to achieve position fixes with an accuracy around 10 cm from Galileo’s first-generation constellation by 2020/2021.

The Galileo Public Regulated Service will also be a focus, with the EC soon to decide upon release dates for the first milestones on the service roadmap. The infrastructure and equipment to support a secure service is being put in place, and I can’t say more for security!

The next generation of European GNSS technology will include multi-constellation EGNOS, Galileo 2nd Generation (G2G) and a transition batch of satellites between the first and second generations to get the best technology proven in flight and working for Galileo users as soon as possible. G2G will reach its System Requirements Review stage in the first half of 2019. To be ready for that we are looking at:

  • clock technology and ensembles
  • inter satellite links
  • propulsion technology
  • flexible payloads and power allocation
  • 5G telecoms networks standards and what we need to do ensure we provide the timing services those networks will need and new signals with time to first fix (TTFF) and power requirements for acquisition of signal that are compatible with 5G devices. Look out for a new pilot signal E1-D to move forward on this.
  • Open Service authentication and support for ARAIM (Advanced Receiver Autonomous Integrity Monitoring).

Finally, 2018 will see the first contract awards of the Navigation Innovation Support Programme. This is a programme specifically designed to encourage R&D, new concepts and new products and to ensure that 2018 is not the last time ESA with the EC and its industrial partners deploy a GNSS service for GSA to operate that changes the world.

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