Fairfax Tech Column

Fairfax Tech Column

29.12.2017 Fairfax Tech Column 75


Now here is an engineering challenge to keep your mind occupied over the Christmas break.

Firstly, take a geostationary satellite delivering Internet connectivity to a large chunk of the earth. I have spoken about the inherent issue with satellite technology before. For the satellite to stay above the same patch of dirt, it has to be geostationary. Without a constant power source to drive it forward, for an object to stay above the same spot on earth, the satellite has to be approximately 35,786km above the earth. This distance gives the frustrating latency users experience when using a satellite – but for some users in remote areas, the choice is high latency or nothing. Most people choose the high latency.

So this much is fairly well known and there are users who experience this method of delivery every day. Yes, it is a little tricky to get an object up to that height and point it back to the earth for an Internet Service Provider to send and receive signals to it and for users to point a dish at this spot in the sky to use it – but engineers have solved these issues and this technology has been in use for many years. The first communications satellite was launched in 1962 and the first high-throughput Internet satellite was launched in 2004. There is therefore a little bit of history in refining this technology.

Now comes the fun part.

Forget your house sitting in a stationary spot on earth and pointing an antenna at the sky. The challenge is to now connect a 544-tonne object travelling at 945km/h relative to the ground but at 13km above the earth. Just having that object doing that for a start is a challenge but the Wright brothers set us on that path from their first powered flight in 1903.

As much as I used to enjoy the fact that there was one last place on earth when I had a legitimate excuse to take a break from communication, some users demanded the airlines deliver Internet connectivity while on flights. The engineering challenge was to connect planes to those geostationary satellites. The same satellites that were designed to stay above a spot on the earth and communicate with one area were now being asked to communicate with something travelling at almost the speed of sound.

The number of aircraft offering Internet connectivity on international flights is now quite astounding. Some airlines have been offering a form of Internet connectivity for domestic flights for ten years but this problem is relatively easy. Use the same mobile towers that our phones use but connect aircraft to them. This gives satisfactory results while flying over the ground in one country but the ocean doesn’t have too many mobile phone towers hence the need for satellite communications.

To solve the problem of connectivity across the oceans, airlines are fitting dual directional antennas on the top of aircraft (you may notice a little bulge on the top of such aircraft) and these antenna constantly adjust their direction to stay aligned to a satellite. This is no simple chalenge.

Once the signal is received by the aircraft, up to six Wireless Access Points – similar to ones in your home – are spread throughout the aircraft to deliver a Wi-Fi connection to all users in the plane. I know your first thought – for years we have been told when we boarded a plane that we must turn our phone onto airplane mode for fear that the signal will interfere with instrumentation on the plane and who would want to be the culprit for causing a plane crash. Well everyone in the technology industry knew there was no proof to support this line touted by airlines and, now they can make some money from phones being left on, suddenly it is all OK. Rest assured, having your phone Wi-Fi turned on during a flight is not going to create any dramas for the flight.

Once all of this technology is linked together, the end result for the user is a slow, unreliable and expensive Internet connection that users can take advantage of for low data intensive activities (such as e-mail) but not for streaming. This is only new technology though – in time, we will be able to use our Internet enabled devices on a plane in just the same way as we would use them sitting on the ground (apart from the inherent latency). If you wanted a small break from your phone while on the flight you may not think that is necessarily a great idea, but no matter which way you look at it, an Internet enabled international flight is an incredible feat of engineering.

Mathew Dickerson