Inmarsat’s Relevancy

Inmarsat’s been around since 1979, operating geosynchronous communications spacecraft using the S-band. Compared to the GPS system, not overly glamorous. In the maritime satcom market, they’re the biggest fish in the pond.

With the current attention focused on how this old satellite company using standard physics to help locate the lost Malaysian airliner, they should become better known.

They’re on it, mate.

Here’s the story in The Malaysian Insider

Britain’s Inmarsat used a wave phenomenon discovered in the 19th century to analyse the seven pings its satellite picked up fromMalaysia Airlines Flight MH370 to determine its final destination.

The new findings led Malaysian Prime Minister Najib Razak to conclude on Monday that the Boeing 777, which disappeared more than two weeks ago, crashed thousands of miles away in the southern Indian Ocean, killing all 239 people on board.

The pings, automatically transmitted every hour from the aircraft after the rest of its 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 was able to provide two arcs, one north and one south that the aircraft could have taken.

Inmarsat’s scientists then interrogated 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,” Jonathan Sinnatt, head of corporate communications at Inmarsat, said.

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 on Monday.

The paucity of data – only faint pings received by a single satellite every hour or so – meant techniques like triangulation using a number of satellites or GPS (Global Positioning System) could not be used to determine the aircraft’s flight path.

They did a fine job with their corporate video, too. Standard concept of a “timeline” script, yet executed brilliantly.


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