LONDON — The British company Inmarsat used a wave phenomenon discovered in the 19th century to analyze the seven pings its satellite picked up from Malaysia Airlines Flight 370 to determine its final destination.
The new findings led Malaysian Prime Minister Najib Razak to conclude yesterday that the Boeing 777 crashed in the southern Indian Ocean, killing all 239 people on board.
The pings, automatically transmitted hourly from the aircraft after other communications systems had stopped, indicated it continued flying for hours after it disappeared from its flight path from Kuala Lumpur to Beijing.
From the time the signals took to reach the satellite and the angle of elevation, Inmarsat provided two arcs, one north over central Asia, the other south to the Indian Ocean, that the aircraft could have taken.
Inmarsat’s scientists then analyzed the faint pings using a technique based on the Doppler effect, which describes how a wave changes frequency relative to the movement of an observer, in this case the satellite, a spokesman said.
The Doppler effect is why the sound of a police-car siren changes as it approaches and then overtakes an observer.
Britain’s Air Accidents Investigation Branch was also involved in the analysis.
“We then took the data we had from the aircraft and plotted it against the two tracks, and it came out as following the southern track,” said Jonathan Sinnatt, head of corporate communications at Inmarsat.
The company then compared its theoretical flight path with data received from Boeing 777s it knew had flown the same route, he said, and it matched exactly.
The findings were passed to another satellite company to check, he said, before being released to investigators yesterday.
Inmarsat said that, for a relatively low cost, its satellites could keep tabs on flights and provide data exchanged between the air and the ground to help organize routes.
Its systems, which are widely used in shipping, have been embedded into surveillance and communications technologies that allow air-traffic controllers to build a picture of where aircraft are and to better manage routes.