Avionics News January 2023 - 30

GOGO'S GOIN' GLOBAL
Continued from page 29
technology that allows Gogo's team to introduce performance
and service innovations that are not possible when
using GEO satellites.
MacDougall said high-speed global connectivity is the
service Gogo's customers have wanted for years. But, like many
new products, while the need was there, the technology just
didn't exist yet.
It does now
MacDougall explained that his team spent the best part of
the last three years researching the equipment and technologies
they'd need to make an affordable, global high-speed broadband
service a reality.
While they looked at using a geosynchronous satellite and a
tail-mounted parabolic antenna - the backbone of every other
satellite service today - they decided it wasn't the best way to
go. The status quo was too limiting.
As with their other connectivity products and services, they
wanted a truly innovative and better solution. So, they set their
sights on the relatively new low-Earth satellite technology.
Before we get too far, here's a quick refresher on GEO and
LEO satellites:
Geosynchronous satellites orbit between 22,000 to 25,000
miles from the Earth's surface, are parked over the equator and
travel at the same speed as the Earth's rotation. That's how they
stay synchronized. Because they are so far away, operators need
fewer satellites to " see " everything but the North and South
poles. In most cases, three GEOs can cover more than 90% of
the globe.
Also, because of their distances from the ground stations,
current satellite connections can suffer from signal latency
problems. It may only be several hundred milliseconds, but it's
enough to be a problem.
Low-Earth orbit satellites inhabit an area that spans from
around 400 miles up to 1,200 miles from the Earth's surface.
Because of their lower altitudes, each LEO satellite can only see
a small portion of the Earth's surface.
LEOs are also traveling at about 17,000 miles per hour and
circle the planet every 120 minutes or so. Because of their speed
and limited coverage area, you need hundreds or possibly thousands
of satellites to create a globe-covering LEO constellation.
" As you can see, the differences between GEO and LEO are
profound, and there are advantages and disadvantages to both, "
MacDougall said. " For us, we felt that LEO was the best way to
go for many reasons. One was it provides true global coverage,
including over both poles.
" There have been arguments made about the value of polar
coverage, but a lot of business aviation aircraft fly over the
poles today. Our customers want to fly the most direct routes
possible, and for many international flights, that track is over
the North pole. "
Another plus in LEO's favor was the fact that it's a new
30 avionics news * january 2023
" The pace of innovation in GEOs is slow because the
satellites cost hundreds of millions to build and launch, so it's
understandable why they stay in orbit for decades, but that
also means the technology can't remain current, " MacDougall
said. " Because the lifespan of a LEO satellite is only three to
five years, we can introduce new capabilities faster to deliver a
better connectivity experience to passengers sooner and keep
current with technology that is being developed. People want
the same services in the air they enjoy on the ground. "
The end was just the beginning
Once the Gogo Business Aviation team had decided to base
the new service offerings on LEO, they had to evaluate all the
various options and select the satellite network and aircraft
broadband antenna providers.
" We quickly realized that LEO and a new-generation electronically
steerable antenna would go hand in hand, " MacDougall
explained. " ESAs are best suited for handling the tracking
speeds needed and can be combined with Gogo's expertise in
things like the Doppler effect. It's incredibly important when the
satellite travels at 17,000 miles per hour in one direction, and
the airplane may be going 600 knots in another direction. That
difference must be accounted for.
" The antenna must be able to steer toward that one satellite,
then quickly shift to the next one to maintain that connection.
Even a difference of a few milliseconds will cause a disruption
in the connection. Electronic steering eliminates those issues.
" When we looked at all the antenna options for LEOs, we
found that Hughes had solved all the problems with their new
ESAs. When we talked to them, we learned about the maturity
of their antenna's design. They hadn't been thinking of business
aviation in particular but were concentrating on how to leverage
their ESAs for OneWeb's LEO network. "
" The world has been waiting for a high-performance, cost-effective,
flat-panel antenna solution to realize the global, highspeed,
low-latency promise of LEO broadband, " stated Reza
Rasoulian, Hughes vice president. " Gogo's selection of the
Hughes ESA solution affirmed our engineering excellence and
unlocked the value of OneWeb's global capacity for in-flight
broadband anywhere on the planet. "
According to Hughes, during tests, their compact flat-panel
antenna has supported data download speeds of up to 190 Mbps
and upload speeds of 20 Mbps, all with an average signal latency
of only 55 milliseconds. While that's not to a jet traveling
at 600 miles per hour, it's close to what the typical terrestrial
broadband connection delivers.
MacDougall explained that Hughes had been a " fantastic
partner " throughout the evaluation, planning and product-development
process.
Avionics News January 2023

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