Somewhat tongue-in-cheek, but I couldn’t resist this…..
This slide is self-explanatory, but I think that to date the industry has been clearly technology-led or dependent. The technology has driven the ability to do these things on this timeline.
PAUSE at up/forward link to explain broadcast mode operations such as DBS/Live TV, AirTV.
10 You have a couple of diagrams in your handouts that illustrate the concepts of geo-stationary equatorial satellite orbit at approx 36,000 kilometres (22,500 miles) where gravitational and centrifugal forces balance and where a satellite may effectively remain stationary over a given point on the Earth’s equator. This slide shows how a constellation of satellites (minimum three required) can provide global coverage when the coverage or footprints of each butt up or overlap with one another. Inmarsat now in fact uses four satellites to share capacity more evenly and also to provide more coverage in more frequently used areas. In fact, during the recent Iraq conflict Inmarsat positioned its spare fifth satellite over the region to provide even more capacity such was the demand from news organisations, military use etc. Note also the vital point that you must have a ground station within the footprint of each satellite (with the notable exception of the Iridium system, which I will come on to shortly) The following slide shows how the four satellite constellations footprints translate into coverage on the ground.
LEO satellites such as Iridium and Globalstar constantly orbit the Earth’s surface and move relative to any given point on the ground. Accordingly, this presents additional challenges and methods of linking the mobile terminal, satellite and ground station. In the case of Iridium, uniquely this is done using inter-satellite links, so the signal is transmitted from one satellite to another to another until the signal reaches a satellite the is currently over the ground station, where it is then downlinked to the ground.
Connectivity 101 WAEA Technology Committee Single Focus Workshop 25 March 2010
Passenger connectivity: a false dawn? First ground to air telephone call (1920) : radio takes off On August 19, 1920, Sir Samuel Instone, chairman of the Instone Air Line was able to have a telephone conversation by wireless radio between his home in London and a passenger on board on of his Vickers aeroplanes en route to Paris. This is thought to have been the first radio telephone call to an aircraft in flight. Another world first for Instone Air Lines………
Receiving stations, billing systems back office systems
Multitude of communications systems Inmarsat L-band GEO satellite Ku-band GEO satellite VHF/HF ACARS Datalink and voice Technologies (flight deck and ATC only) Gatelink (Terminal WLAN) Terrestrial (eg Aircell, Wi-SKY) Iridium L-band LEO Satellite Satellite Technologies Radio Technologies
Radio and Satellite Transmission Satellite (Ground) Station Radio (Base) Station Satellite Up link Forward link Return link Down link All elements of each system may vary: frequencies used, data rates, type of satellite, orbit, range of transmission, aircraft equipment etc., etc . Radio Transmission Satellite Transmission
In-flight communications options Bandwidth Less More (Kbit/s) (Mbit/s) Geographical availability Global Regional L-band higher rates Ku band Satellite DBS/DVB TV L-band Low and mid rates Air-to-ground/Terrestrial Safety Services Real time TV Cellphone Internet