How exactly 'groundbreaking' number crunching found Flight 370

Monday's announcement brings new questions about the mystery that has captivated the planet for more than two weeks. It also provoked a call that all airliners be constantly tracked.
The mathematics-based process used by Inmarsat and the UK's Air Accidents Investigation Branch (AAIB) to reveal the definitive path was described by McLaughlin as "groundbreaking."
"We've done something new," he said.
Here's how the process works in a nutshell: Inmarsat officials and engineers were able to determine whether the plane was flying away or toward the satellite's location by expansion or compression of the satellite's signal.
What does expansion or compression mean? You may have heard about something called the Doppler effect.
"If you sit at a train station and you listen to the train whistle -- the pitch of the whistle changes as it moves past. That's exactly what we have," explained CNN Meteorologist Chad Myers, who has studied Doppler technology. "It's the Doppler effect that they're using on this ping or handshake back from the airplane. They know by nanoseconds whether that signal was compressed a little -- or expanded -- by whether the plane was moving closer or away from 64.5 degrees -- which is the latitude of the orbiting satellite."
Each ping was analyzed for its direction of travel, Myers said. The new calculations, McLaughlin said, underwent a peer review process with space agency experts and contributions by Boeing.
It's possible to use this analysis to determine more specifically the area where the plane went down, Myers said. "Using trigonometry, engineers are capable of finding angles of flight."
No surprise
Experts said they weren't surprised by the news that the flight traveled along the southern track -- one of two possible paths revealed by satellite data last week. The possible northern track toward Pakistan would have been heavily monitored by radar. Pakistan had said it found no evidence of Flight 370 on its radar systems.
http://edition.cnn.com/2014/03/24/world/asia/malaysia-airlines-satellite-tracking/index.html

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