Astronics AeroSat

Fresnel lens-horn design coupled with Ku-band transmission works well for bizav internet reception.

Astronics AeroSat FliteStream F-Series system is a fuselage-mounted internet connectivity solution ideal for airline and VVIP aircraft. FliteStream F-Series is composed of an antenna (FMU), transceiver (HPT), and satellite modem & antenna controller (ACMU).

This ability of a Fresnel lens to take a weak light source and magnify it was the reason it was used in lighthouses. An example of this exists today. In Florida, the original 9 ft tall Fresnel lens (hand-blown in Paris, France) still sits atop the St Augustine lighthouse. Although the original low-powered light source has since been replaced with a 1000 watt bulb, the Fresnel lens still directs the beam.

Fresnel lens-horn design

Astronics AeroSat's Fresnel lens-horn design enables the antenna to capture RF energy at greater incident angles. This efficiency makes it especially advantageous when flying in latitudes above 75 degrees. Again, think back to that home satellite system. The dish points towards the satellite on the equator. If your house was located on the equator the dish would point straight up; in Barrow, Alaska, at 71 degrees north, the same dish would be aligned almost horizontal.

The signal gets weaker as the latitude (angular difference) between the satellite and recipient increases. So the Fresnel lens-horn acts like a bigger diameter dish, achieving a higher gain and sensitivity than traditional satellite antennas. The end result is that the Astronics AeroSat product continues to provide internet and television in locations where other antennas tend to drop offline.

FliteStream F & T series

When it comes to connectivity, Astronics AeroSat produces 2 product lines. Airline customers (approximately 500 airframes have it installed) benefit from the fuselage-mounted FliteStream F-Series. Business aviation is served by the FliteStream T-Series, a tail mounted system available in 2 options: T-210 or T-220. T-series versions consist of a Gimbal Antenna Unit (GAU) at 23.5 lbs, Power Amplifier (PAU), Antenna Control & Modem Unit (ACMU), Low Power Transceiver (LPT), and a diplexer. Connection speeds are specified in excess of 40 Mbps.

The T-220 is considered an upgrade in terms of worldwide coverage of live TV. High speed data and global live TV is provided by Panasonic (which advertises coverage over 99.6% of the world's flight routes), while customer care and subscription services are delivered by SatCom Direct.

Astronics AeroSat uses Ku-band

Astronics AeroSat specializes in the Ku-band frequency range under an open-architecture philosophy to prevent locking the customer with a specific satellite network or provider. The modem in the ACMU is compatible with a number of broadband providers so that flight departments can choose from a variety of options to meet their specific needs.

There's a lot of hype these days about Ka service. Matt Harrah, president of Astronics AeroSat, explains why. "Ka-band has recently garnered the majority of the airborne connectivity news because it is new and promises faster internet speeds in flight," declares Harrah. "Unfortunately, this has confused the market, making customers think Ku-band means slow internet and Ka-band means fast internet.

However, this is not factual, as the speed from Ka-band is solely a function of how the satellite was designed, using multiple small antennas to cover a region creating spot beams versus the traditional single large antenna creating a single wide beam over an area. New Ku-band satellites being launched today also have the same spot beam architecture providing similar speeds."

Harrah also points out that Ku-band satellites are more prevalent as there are relatively few operational Ka-band satellites in orbit. All other things being equal, reflector gain is proportional to frequency squared. A Ka receiver operating in the 26.5–40GHz range has a mathematically better sensing capability than a Ku receiver at 11.7–14.5GHz. However, the Astronics AeroSat design offers a distinct advantage over standard Ka antennas.

Further, path loss (the quality of signal to noise) is also proportional to frequency squared. This translates to a higher noise ratio when it comes to Ka signal quality. Rain has a tendency to absorb signals over 11 GHz, so Ka is also subject to rain fade–an important consideration for operators that frequently visit tropical regions.

Business jet applications

In regards to business aircraft, As­tronics AeroSat's tail mounted T-se­ries have been FAA-approved for the Gulfstream G-IV/G-IVSP family and the Dassault Falcon 7X along with the Gulfstream G-450 and Bombardier Global Express XRS/5000/6000 on its heels.

According to Matt Harrah, 2018 is an exciting year for the company. "Multiple sequential aircraft STC programs are being kicked off to maximize business aviation market availability for quick installations for interested customers," says Harrah.

Since its inception in 1997 AeroSat has been highly regarded for its technical expertise and innovative designs. In 2004 Rockwell Collins began using AeroSat antennas for their Tailwind DBS-TV system product line.

There's no doubt that the combination of Astronics–a global powerhouse in the world of aerospace and AeroSat–with its strong history of SatCom engineering will produce some exciting products now and in the future under the Astronics AeroSat brand.

Shannon Forrest is a current line pilot, CRM facilitator and aviation safety consultant. He has over 10,000 hours and holds a degree in behavioral psychology.



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