Both commercial and private aircraft are increasingly carrying antennas that link them to communications satellites or terrestrial towers that link planes to the Internet. Ground-based systems are popular now, but satellite links are widely considered to be the future for global connectivity. Many market watchers feel this trend has reached critical mass, beginning the spiral of rising volumes and falling prices that makes systems affordable enough for mainstream markets.
In-Stat predicts that in-flight Wi-Fi services will generate revenues of more than $1.5 billion in 2015, when 6100 commercial planes will have Internet access. That’s more than triple the number of Wi-Fi-equipped planes last year.
In the U.S., Gogo has gained solid market share with a terrestrial system that works much like a cell-phone system, communicating over a network of towers. The technology is used by both commercial and business planes.
While this technology has fared well domestically, many vendors feel that satellite links are more viable in many international regions. Gogo plans to begin providing Ka-band satellite links to extend its reach outside the U.S.
Though terrestrial communications can be less expensive, it may not be practical for many aircraft to carry both types of antennas, partially because the protrusions that hold the antennae cause drag. Additionally, air-to-ground (ATG) networks are costly and time-consuming to deploy.
That may force many to pick one connection, either looking earthward or to orbiting satellites. One factor behind this decision is that it’s not practical to bounce between terrestrial communications and satellite links.
“Development of integrated systems requires significant investment, which would only be supportable if there were more ATG networks globally to inspire such innovation,” said Frederick St.Amour, Sales Vice President for Row 44. “The primary limiting factor is the lack of commercially viable equipment sets and software that enables such switching.”
Though satellite systems don’t require as much switching as ground-based communications, they can’t track a single satellite during a long flight. When planes fly across the U.S., for example, they usually need to access three satellites. Switching from one satellite to the next is not as simple as when cell phones shift from one terrestrial antenna to another.
“There’s a momentary break when you switch,” said Dave Jupin, Product Line Manager at Hughes Network Systems. “We have to determine when to make the switch and reorient the antenna so it’s focused on another satellite.”
Switching from one antenna to another highlights the complexity of these systems. Antennas must always focus precisely on the satellite they’re communicating with. They must also work at varying speeds, and beams must be very accurately positioned so they don’t cause interference with other communication signals.
“To make these systems work, you have to provide Doppler compensation for jets flying at high speeds,” Jupin said. “You’ve also got to be sure that the plane’s communications don’t interfere with other satellites.”
At present, most of the satellite links use the Ku-band, a technology that is widely deployed. That’s likely to change over the short term. Satellite providers are gearing up for Ka-band links, which provide far more bandwidth.
“Everyone’s looking forward to Ka-band; it offers more capacity. In the next three to five years, there will be enough Ka-band satellites to support aircraft,” Jupin said.
One example of this interest level came in April when Honeywell signed a 20-year pact with satellite provider Inmarsat to sell aircraft antenna that will communicate with three Ka-band satellites that Inmarsat plans to launch over the next couple years. Honeywell expects to earn nearly $3 billion over the two decades of the deal.
While providers look to the future, existing satellite technologies are not going away. Vendors can use new technologies to squeeze more capability from satellite systems that are already orbiting.
“We introduced a Ku-Band option combined with a router that uses compression algorithm to optimize available bandwidth,” said Yannick Dansereau, Lead Product Manager for Cabin Systems at Bombardier.
Some techniques for reducing demand for satellite bandwidth will occur on the aircraft. One is to store some of the most commonly accessed material on hard drives before the aircraft takes off. Servers can then disseminate it without communicating with the satellite.
“There’s a significant increase in the amount of content that may be stored and updated to support the content in greatest demand by passengers,” St.Amour said. “In the future, low-cost data and content loading technology will be deployed, enabling rapid updating of onboard servers with extremely large quantities of data. This will shift data loading from satellite links and physical efforts to terrestrial GSM and Wi-Fi links, reducing costs and security risks and improving commercial flexibility.”