[Avionics Today 04-29-2015] Global Eagle Entertainment and German antenna developer Quantenelektronische Systeme GmbH (QEST) are teaming up to bring aviation a mechanically steered antenna that will enable global Ku-band connectivity and high speed broadband in-flight. As air traffic all over the globe increases and connectivity becomes ubiquitous in air travel, the companies are looking to provide airlines with an antenna that operates without geographical or systemic boundaries.
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| GEE and QEST executives unveil global Ku antenna at Airport Interiors Expo in Hamburg, Germany. Photo: GEE |
“It is critical that we build an antenna where the airlines don’t have to make a choice whether they will divvy up some of their connected systems to equatorially efficient antennas and northern or southern routes into a different kind of antenna. You always want to build a system where the customer doesn’t have to choose,” Aditya Chatterjee, chief technical officer at GEE told Avionics Magazine.
The new antenna will be compatible with GEE’s current installation architecture and Supplemental Type Certificates (STC), and will be both line-fit and ARINC 791 compliant. The growing need for connectivity combined with both the pick up in global air traffic and aircraft flying more long-haul routes has fostered the need for a more flexible antenna. GEE and QEST see the global Ku antenna as well poised to capture this market.
“There is a general increase in the demand for connectivity across the globe. When you look at that increase of demand it’s coming from African countries, Middle Eastern countries, and certainly South American and Southern Asian countries. So, overall the requirement to support a very efficient connected system close to the equator is a given,” said Aditya.
Traditionally, lower profile antennas are limited in how close to the horizon they can look, restricting their reliability to aircraft that don’t fly equatorial or polar routes. The GEE-QEST antenna, however, which is scheduled for commercial availability by mid-2016, will use a steerable pointing system to optimize beam shape and coverage at all latitudes. The companies aim to enable this through design tweaks, such as an oval-shaped aperture that is built with more up-to-date micro-honed technologies, as opposed to a traditional rectangular model.
Another key detail in the new antenna development is the addition of a third axis that will allow the antenna to more easily access visible satellites.
“Usually, a mechanically steered antenna such as this would have two axis: elevation and azimuth, which has some differences and advantages over the equator in the sense that, not that it doesn’t work under the equator, [but] it would actually need more space segment,” Chatterjee said, noting that a mechanically steered antenna often has some deficiencies when flying over the equator where it needs more satellite bandwidth compared to flying anywhere else. “But when you add the third axis, which we call the tilt axis, you could position the aperture more precisely toward the satellite of your choice, thereby transmitting and receiving higher levels of signals from the specific satellite.”
The companies did come across some regulatory challenges while endeavoring to develop a versatile mechanically steered antenna. The third axis became the solution to these challenges, as it cuts down on beam degradation often encountered by lower profile antennas as they approach polar regions by maximizing optimal beam shape.
“Ideally the antenna physicist would use a circular dish because it is uniform in any direction. It creates a nice beam, which basically looks like a baseball bat, so something very accurate. If you have an aspect ratio you have one side of the antenna beam that is very small, very focused and the other dimension is not as focused as you would like to have it. This is simply due to the fact that you have to have a flat form factor on top of an aircraft. With that you are not allowed to point in any direction even if you could do so mechanically,” explained QEST’s Chief Commercial Officer Michael Stobinski, who likens the restrictions on the beam to limiting a car’s use of high beams at night to prevent it from blinding other drivers on the road. But this is where the third axis comes into play. “With the third axis and the tilt angle, we can now have an additional degree of freedom where a specific beam shape can be pointed in a way to the satellite so that you don’t interfere with adjacent satellites,” he added.
Frequency was also a factor in developing a worldwide solution, with Ku band winning out due to its prevalence around the world. The companies decided that developing a system that was compatible with the spectrum as well as current Ku systems was the best option.
“When Ka came along, rightfully so because of the lack of enough orbital places, [satellite operators] directly went into high throughput,” said Chatterjee. “We looked at Ka, and still now it is more regional, and not in all regions. What we wanted was technology which would work across the globe.”
Prior to announcing its partnership with QEST, GEE inked an agreement with SES, which has committed to a significant investment in Ku-band payloads. The IFC provider will have access to Ku-band wideband and High Throughput Satellite (HTS) spot beam capacity from the SES 12, SES 14 and SES 15 satellites, which are currently slated for launch in 2017. The deal with SES, which has been designing its satellites with a greater focus on aeronautical connectivity, paves the way for higher throughputs with the global Ku-band antenna.
“So now you not only have a global coverage with wideband today, the path is very clear that we would have high throughput satellites in the next one and a half years, which would also cover the most populated regions of the globe,” Chatterjee explained. “The Ku-band technology, whether it is the current system or the next generation global system, it is forward compatible. You can use wide-band now and you can immediately with the exact same infrastructure and hardware, jump onto Ku HTS where it is available. That’s the fundamental reason why we use Ku, and we plan to continue using Ku.”
Chatterjee added that the new antenna will be able to receive the entire range for Ku band and could easily provide more than 100 Mbps per plane. Stobinski said QEST set out from the start to have a design that was as open as possible. Come 2016, the companies plan to have a singular antenna that can provide the full gamut of Ku-band satellite services.
“Our product is designed for customers to do what they want to do with a single product, not having to use multiple products for different areas of application. For example, if you look at combining reception of [Digital Broadcast Satellite] DBS TV signals, which typically come through a Ku wideband satellite on the one side and simultaneous IP data traffic on a different subset of the frequency band, it’s perfectly feasible with our antenna array. Others need to have two antennas on the fuselage of the aircraft to be able to have IP data traffic as well as TV reception. This can all be handled with one generic product,” said Stobinski.