Inmarsat is putting contingency plans in place should it need to bolster Ka-band satellite capacity in the event it encounters congestion on its forthcoming Global Xpress (GX) service. But the London-headquartered firm “is confident” that GX will be able to provide more than ample bandwidth for users.
GX will support connectivity for business and commercial aircraft, government aircraft, ships, and news agencies reporting from remote regions.
“[Satellite] network operators always say, ‘If there is any congestion, it’s a problem we’d love to have and Inmarsat is already considering the necessary long lead items to put in place should it be required,” says Inmarsat director of aeronautical business David Coiley, confirming that adding more satellites to the planned three-satellite I-5 Ka constellation for GX would be a “way to do it” down the road.
Each of the three I-5 satellites slated for launch will carry a payload of 89 Ka-band spot beams, which will provide virtually global coverage, except for the poles. Additionally, each satellite will carry six steerable beams that can be pointed at high-traffic commercial or government areas.
“Interestingly, the major maritime and aviation routes overlap quite nicely so we’ve already looked at areas in the world – such as the North Atlantic, Western Europe and Southeast Asia – where we’re looking to double up Global Xpress capacity. Plus we have steerable spot beams over and above that,” says Coiley.
Serving “the maritime world, the land world and the aviation world”, he notes, means that Inmarsat’s $1.2 billion investment in Global Xpress “is pretty safe because we’re not dependent on the number of passengers who swipe a credit card session to surf the web.
“The business model, though positive, has yet to be proven whether commercial aviation alone can sustain the numbers being bandied around out there.”
Inmarsat is “absolutely on track” to launch the first I-5 satellite at the end of 2013 and offer global coverage “by the fourth quarter of 2014, according to Coiley. Honeywell, which was chosen to develop, produce and distribute onboard hardware to users of GX, will start delivering in “the first quarter of 2015”, he says, adding that the firm has “committed an awful lot of resources” to the project.
A core part of what Honeywell is addressing is ensuring that the Ka-band antenna and radome to support GX will follow the Arinc 791 standard, which is the same spec followed for installation of Ku-band antennas on aircraft (so, in essence, the same attach points will be used).
“What that means – and certainly one of the dialogs going on – is that the aerodynamic design for the radomes may be identical because it’s more efficient for airframers to have one system. Under that radome, you could have different antenna apertures, whether Ku or Ka. However, if you have the same radome, the Ka-band antenna will give superior economics and superior performance [over Ku]. We can squeeze more out of the aperture. We’re looking at 45cm to 60cm, which is typically the size of a Ku-band system so if we’re going to sit under the same [sized] radome, we might as well expand up to that size and give superior performance and throughput,” says Coiley.
Another “undeniable, fundamental advantage of Ka-band” over Ku, he says, is “if you look at a spectrum chart and see how much spectrum in Ka is available versus the amount of spectrum in Ku-band, it’s something like four times as much spectrum”.
A now clear competitor to Inmarsat for inflight connectivity business is Intelsat, which last month partnered with Panasonic Avionics to provide the company with up to 1 Gbps of capacity on its planned new ‘Epic’ satellite platform. The two firms touted that airlines operating over the high-traffic North Atlantic corridor will be able to access “the highest possible bandwidth” for their passengers when the first Epic satellite, known as Intelsat 29e, launches in 2015.
“As you know, everyone likes to shout that they are the biggest and the fastest. I would caution people to look at the performance of Epic, and ask: ‘How does it tail off outside the corridor? What do they hand off to?’ Jet streams move around quite alarmingly. They can spoil not only your barbeque but can impact how reliably or consistently aircraft can experience this vaunted 80 Mbps [per aircraft] performance.”
He adds: “With GX we hand over to spot beams seamlessly as we do with [our current L-band service SwiftBroadband]. I think [Panasonic is] accentuating the positive by saying that the optimum performance is under Epic spot beams but they’re covering a relatively narrow field of the earth’s surface.”