ESN focus: view from the air
Ahead of ESN Air starting to test in the field, Philip Mason talks to project lead Sebastian Pampe about the challenges of rolling out a world-first air-to-ground mission-critical broadband network.
My title is the lead for the ESN Air part of the programme. ESN Air is one of the products that’s being delivered as part of the overall network, providing coverage between 500 and 10,000 feet, and up to 12 nautical miles out to sea.
How is the ESN Air project constituted?
In terms of scope, the project consists of three distinct parts. Firstly, there’s the air-to-ground [A2G] network itself, which is separate from what we’re building on the ground.
The overall requirement is to provide seamless coverage between the ground and 10,000 feet, with the terrestrial network providing coverage between zero and 500 feet. If you’re in an aircraft, you have to have that continuous coverage as you take off and land, kind of like vertical roaming.
The second part of the project is what we call the aircraft communication system, or ACS for short. That is being delivered by Chelton, with the contract having been awarded in the summer of 2019.
They are essentially delivering the device, which is going to be fitted into the aircraft, replacing the legacy TETRA system. The ACS will also host the Kodiak software application, supporting critical voice and data transfer. The whole project is a world first.
The third part is the integration of parts one and two – the ACS and air network – into the wider programme.
What are the particular requirements for the project, both in terms of the network and the communication devices? How were those requirements identified?
The requirements were developed in conjunction with the user community via an information-gathering exercise. We went through an options phase at the beginning of the project, looking at different technologies which could have been leveraged, an example of which would be satellite.
We also carried out a review of the ground network to ascertain to what extent it reaches into the air. That was to validate whether we needed an air network in the first place. This is an expensive part of the project, and we have to make sure that we’re delivering value for money.
In terms of the devices themselves, the ACS technology is going to provide a step-change from what users currently have, same as on the ground. Again, we’ve been working with the user community throughout the whole process, translating their requirements into our procurement strategy.
Going back to the coverage piece, how is the network infrastructure deployed?
We’ve worked in close collaboration with EE, looking at what’s available and where the disparity might be in terms of what we need. We’ve tried to go for towers or masts situated on the top of hills, with the aim of giving ourselves an additional lift in terms of providing coverage.
What have been the specific challenges when it comes to this part of the roll-out? Given what you’ve just said, an obvious one would appear to be providing coverage at such an elevated height…
That is a considerable challenge, yes. Because of the nature of the project, we’re generally not able to use smaller masts mounted on the side of buildings, because, as you indicate, they would be too near to the ground.
What we’ve done instead is develop a radio plan taking in approximately 90 sites across the whole of Great Britain, sharing infrastructure space with other providers at a height that’s required. Again, from a value-for-money point of view, it wouldn’t make sense to build that many of our own masts, so we’re borrowing other people’s.
Another challenge is the sheer variety of landscape that makes up the British Isles. We have to accommodate urban, rural, maritime and so on, alongside many different types of weather conditions. It hasn’t been the best summer this year, which has impacted on our testing efforts, at least to a degree. Just to put it into context, the air network will cover three quarters of a million cubic kilometres.
Ultimately, the complication presented by the network is simply how technical and far-reaching the requirements for it are.
To read the full version of this article, see the October issue of the BAPCO Journal.
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