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How 'groundbreaking' # crunching found path of 370
送交者:  2014年03月24日21:46:21 于 [世界军事论坛] 发送悄悄话

How 'groundbreaking' number crunching found path of Flight 370

By Thom Patterson, CNN
updated 1:35 PM EDT, Mon March 24, 2014
Watch this video

Experts: Flight ended west of Perth

STORY HIGHLIGHTS
  • Satellite experts use "groundbreaking" process to track Flight 370's final hours
  • The Malaysia Airlines Boeing 777's last position was "in the middle of the Indian Ocean, west of Perth"
  • Satellite official: Hopefully, this will trigger a "mandate that all aircraft should be constantly tracked"

(CNN) -- Monday's announcement by Malaysia's Prime Minister acknowledging that missing Flight 370 ended in the southern Indian Ocean opens the door to a big question: How did new number crunching confirm the Boeing 777's path?

Now we know for sure "there's no way it went north," said Inmarsat Senior Vice President Chris McLaughlin.

Malaysian Prime Minister Najib Razak said Monday that the plane was last tracked over the middle of the Indian Ocean, west of Perth, Australia. Malaysian Airlines has informed passengers' relatives that "all lives are lost," a relative told CNN.

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."

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"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."

What could wreckage tell us about Flight 370's fate?

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.

"It was very difficult to believe that no watch captain" along the possible northern path "would've seen a burning or distressed aircraft in the sky during the course of their watch," said McLaughlin.

Is the more pinpointed flight path now focused enough to increase the chances of finding wreckage from the plane?

If the flight definitely ended far from land, does that support the theory that the plane was not hijacked? It's just one question of many that investigators likely will be pondering in the coming days.

Hours before the Prime Minister's announcement, Australian officials said they had spotted two objects in the southern Indian Ocean that could be related to the flight, which has been missing since March 8.

One object is "a gray or green circular object," and the other is "an orange rectangular object," the Australian Maritime Safety Authority said.

"This is obviously a major tragedy," McLaughlin said. "The only thing you can hope is that from this, just as the Titanic resulted in (new safety legislation), that from this, there will be a mandate that all aircraft should be constantly tracked."

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  解决这类问题,最终还是要靠 solid - 生人 03/24/14 (504)
      The PING don't tell where - lotofrain 03/25/14 (459)
        有那6个握手信号的准确信息,就可以推出航班的大致航迹 - 新用户 03/25/14 (488)
        如果有6个圆圈的话,是不是可以看出圆圈往哪里移动? - 生人 03/25/14 (463)
          The final anaysis is based on - lotofrain 03/25/14 (533)
            没有人说是确切位置,海事星是通信星,但多个ping个可以看出 - 生人 03/25/14 (460)
              They indeed use doppler shift. - e-mail 03/25/14 (432)
            Indeed, they used the Doppler - 透气 03/25/14 (470)
    The loci only indicates the - oldfarmer 03/24/14 (495)
      你如果细看国外媒体的图,上面有NTSB推测的可能路径  /无内容 - 生人 03/24/14 (487)
        比如这张 - 生人 03/24/14 (813)
          这路线图已经好几天了,不是最新才有的 - highsierra 03/24/14 (496)
            是的,北线是possible,not probable, 大 - 生人 03/24/14 (504)
  This is possible only if the - oldfarmer 03/24/14 (454)
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