Inmarsat used the Doppler effect”a transmission's frequency change due to the movement of a satellite or aircraft”as the basis for a method of modeling Malaysia Airlines Flight 370's final flight path.
Once the company tracked the plane's final ping, it performed groundbreaking data analysis to try to establish which of two possible arcs the plane travelled along and where its perplexing flight might have come to an end. When the data were compared with data for the known paths of other aircraft, it formed the basis to establish the likely route taken by Flight 370.
Chris McLauglin, an Inmarsat senior vice president, said initially the data indicated the plane, could be north or it could be south, and what we've done is refined that with the signals we got from other aircraft. Previous aircraft provided a pattern, and that pattern to the south is virtually what we got in our suggested estimate.
The company was able to provide a location with a margin of error of about 100 miles, but it couldn't be more precise because the satellite that received the Flight 370's pings was a 1990s model and wasn't fitted with the Global Positioning System capability that would narrow the location to a handful of meters.
Image courtesy of The Independent.