AviTech Reader

Rarely do we concentrate on entertainment as a major part of the Avionics in an aircraft. Just until recently, when global trends force us into it. Nowadays, portable computers, can be tablets, laptops or whatever have become the norm and this has been observed as a way of attracting customers. What am I saying…you may wonder-it has been observed that airlines are trying their best to claim their market share by providing passenger with something special, internet connection.

Many aircraft today, both private and commercial have antennae than communicate with satellites or towers that help access the internet. Even though most of the equipment are towers(on the ground), satellite sources have recently been hugely adopted and these increase in use has pushed their prices lower enough for more affordability. From an article I read in the SAE Aerospace engineering issue of 15^th August 2012, In-Stat predicts that by 2015, 6100 commercial planes will have internet access-3 times the number that had last year(2011). In USA for example, Gogo has been doing the tower thing which has been nice and reliable domestically but airlines go past country boundaries hence the need for satellite services. Comparatively, Satellite services are more expensive, but again it is not pragmatic for many aircraft to carry both types of antennas-the drag caused will be too high. Also, Air-To-Ground (ATG) networks are time consuming to set up.

This obliges airlines to pick one connection, as does not sound politic to have both, neither is it better to bounce between ATG’s and satellite connections. Another issue is that though satellite connections seem a viable solution, an aircraft on a trans-continental or trans-ocean trips will not be able to track one satellite all through. It needs to connect to at least three of them and the switching is not as easy as a cell phone switching between towers as one travels in a car. There is need for attention to some minute details (like Doppler compensation depending on speed) for a successful re-orientation and precise focus on another satellite to facilitate a continuous connection. Another pothole to look out for is to ensure that satellite communication does not overshadow the link between the air traffic controllers and the pilots.

So far, most of the links to satellites use Ku-band, a well-established technology-though many are anticipating the Ka-band links that will have a larger bandwidth.

The other challenge is a design one, because many passengers will be accessing the internet and doing may be 4-5 things, facebooking, listening to music, watching a movie…you see. You can imagine most of the passengers using the internet and the situation is not the same as that in a local cyber café because in an aircraft there are power consumption and weight that we will be adding just by adding few more routers to make the internet connectivity more efficient. Also, it won’t be a good idea if passengers have to wait every time the system is switching from one satellite link to another.

This calls for a very good Real Time Operating System (RTOS). Bombardier, working hand to hand with satellite provider Inmarsat, is among the companies that have surmounted all these challenges and established a very nice internet access system.