How does the GPS system of an airbus A319 work?
Ive bin playing Flight simulator X for a while now but there is one thing that i realy dont understand. If for example, i fly from Amsterdam to London i see a purple line on the radar. This line goes from Amsterdam all the way to London. However, if, for any reason, i loose track i cant find the line back. So, if i loose the purple line out of my radar screen how do i get back on track?


Pilotage, dead reckoning, or call ATC to help them get your candy ass headed back towards where ever in the hell it is you said you are going. I’m sure the boss WON’T want to be talking to you about that when you get back.
Airliners do not use GPS alone. The on-board flight management system integrates information from multiple GPS receivers, multiple inertial reference systems, multiple VOR receivers, etc., to determine the aircraft’s position.
GPS does not provide the magenta line on the navigation display; the FMS provides that. If for some reason you are not flying the magenta line and you lose track of it, you can use the range adjustment of the ND to find it, along with switching modes to see everything in front of and behind the aircraft (in case the line is already behind you).