Scott Carmichael

Source: SES / SES-15 launch page

 

In our recent article discussing the launch and operational readiness of the new SES-15 satellite, we mentioned that it would add “HTS” coverage for aircraft connected using our 2Ku system. But what exactly is HTS, and how does it benefit passengers looking to connect when they fly?

In a nutshell, HTS stands for high throughput satellite, and as the name implies, it provides higher throughput than a traditional satellite. Throughput is a measure of data transfer speed, and in satellite technical terms is driven by the amount of frequency available for error free transmissions to and from a satellite to a target destination (which can be an aircraft, ship or other ground-based satellite terminal). HTS employs a much more efficient use of satellite frequencies and therefore equals higher throughput, which equals more data that can be sent through the satellite. This is particularly important because satellites are assigned specific frequency ranges they are allowed to operate within, which places limitations on what is possible.

But perhaps the biggest difference between a traditional satellite and an HTS satellite comes from a change in antenna technology. Normally, a satellite in space receives and transmits data using just a couple of antennas (technical term is transponder). These transponders beam data down to the ground and often cover very large areas, in some cases entire countries could be covered with just one beam, such beams are commonly referred to as “wide beams”.

Source: SES

Wide beams mean that everyone connecting to this satellite must share the bandwidth with everyone else in the same beam because everyone is communicating using the same transponder antenna. With HTS satellites, these beams are more numerous and are much, much smaller – which explains their name: spot beams. A spot beam is a satellite beam that covers a small area, often specifically selected to provide pinpoint accurate coverage for a specific place, maritime route or aviation route. In the coverage map of the new SES-15 satellite above, you can see exactly what spot beams are designed to do. When you look at the route between the continental United States and the islands of Hawaii, you’ll notice a line of overlapping ellipses – these are the spot beams. These spot beams were specifically planned and designed to ensure aircraft flying to and from Hawaii have uninterrupted coverage from the mainland all the way to the idyllic islands. When they launch 2Ku, Alaska Airlines is a good example of an airline that will benefit from this mainland <> Hawaii coverage as they fly a lot of passengers on this route.

These smaller beams bring us to the next big advantage of HTS satellites; with smaller beams, you serve fewer customers within each beam, which means more bandwidth to go around, which results in faster speeds! To help clarify further, imagine a huge water hose, trying to quench the thirst of 1000 people. Clearly, not everyone will be able to get a drink, and it becomes quickly apparent that there just isn’t enough water to help everyone. Now image that same amount of water coming out of 100’s of tiny hoses – suddenly everyone can grab their own hose or share it with a few others. The end result is that everyone gets a drink, and there is no overcrowding. Spot beams work exactly the same way – if a single beam covers half the country, there will be 1000’s of people on the ground trying to share the available bandwidth, along with 100’s of aircraft flying within the beam. Pretty quickly, you’ll run into congestion which equals lower performance. By using spot beams, we can easily host 100’s of aircraft on a single satellite while still ensuring everyone has the same incredible 2Ku experience we aim to provide.

And finally, HTS satellites offer better performance simply because they are newer – as with all technology, newer usually means faster, more innovative features and the ability to do things older satellites simply can’t. The new SES-15 satellite is a great example of this; instead of using the old rocket powered system for making orbital maneuvers, SES-15 uses the newer all electric propulsion system, making the entire satellite much lighter than a traditional design.

As more and more HTS satellites are launched, Gogo 2Ku is ready to take advantage of them, proving that the open architecture of 2Ku really is the best possible option for connected aircraft around the world.

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