（1）根據MH370航班最後一次 ping 海事衛星接收天線角度和飛機載油量，確定飛機可能在南北兩條走廊上。注意這個結論是基於距離， 有對稱性， 所以有南北兩種可能。
（2）根據同步海事衛星接收的多次ping 的微波信號的多普勒效應分析，對稱性被打破，隻有往南一種可能。
幾點說明：
a) 在衛星通信中考慮多普勒效應， 是成熟技術，不是新技術。衛星通信是微波通信，與手機通信一樣是無線電通信的一種。
b) 用微波信號傳輸的多普勒效應對失事飛機定位，是多普勒效應的新應用。
c) 這個新的應用，用已知飛機的航程做過對比分析，得到了驗證。目前衛星發現的大麵積殘骸，初步證明結果的正確。飛機在南印度洋找到，隻是時間問題。
British satellite company Inmarsat’s Chris McLaughlin explains how scientists were able to work out the final flight path of the missing plane, flight MH370. Using models of the last signals sent from the Boeing 777 and comparing that with previous Malaysia Airlines data, they were able to narrow the final flight path down to the southern Indian Ocean.
(CNN) — Japan and Thailand both said Thursday they’ve sent new satellite images to Malaysia showing separate debris fields that could be related to missing Malaysia Airlines Flight 370.
The announcements come just a day after Malaysian officials announced a French satellite had found 122 pieces of something floating nearby, and days after similar findings in the same general area — all part of the search for Flight 370. The plane vanished March 8 with 239 people aboard.
d) 海事衛星是同步衛星，多普勒效應貢獻來自飛機的飛行速率與方向（速度矢量）。
(3) 什麽是多普勒效應？
一列迎麵開來的火車，鳴笛的聲音會比停著的火車聲音尖銳（高頻），而離開的火車鳴笛會更低沉（低頻）。迎麵開來的汽車鳴笛，在會車的過程中，你聽到的聲音會從尖銳到低沉。這是聲波的多普勒效應。
An animation illustrating how the Doppler effect causes a car engine or siren to sound higher in pitch when it is approaching than when it is receding. The pink circles are sound waves. When the car is moving to the left, each successive wave is emitted from a position further to the left than the previous wave. So for an observer in front (left) of the car, each wave takes slightly less time to reach him than the previous wave. The waves “bunch together”, so the time between arrival of successive wave fronts is reduced, giving them a higher frequency. The waves “stretch apart”, so the time between the arrival of successive wave-fronts is increased slightly, giving them a lower frequency.
以上為多普勒效應示意圖。以下為水波的多普勒效應。隻要是波，就有多普勒效應。 電磁波也一樣。
Doppler effect of water flow around a swan
