This question which claims that an altitude of 55,000 ft. was observed on a passenger's in-flight entertainment system on an Emirates B777 made me wonder: What are the normal sources of information for the flight data displayed on passenger IFE systems?
Of particular interest are the common sources for the following information:
- Altitude (Is this a pressure altitude? Indicated altitude? A GPS-measured altitude? A radio-altimeter-measured absolute altitude?)
- Speed (This seems to typically be true ground speed, which I'd assume comes from GPS, but any further insight would be appreciated)
- Latitude/Longitude position (Is this from GPS? INS? radionav? some combination?)
- Wind speed