Some points about the inmarsat lines of position.
- According to spec GSM must infer distance between base station and user equipment via round trip times with an acuracy of better than 550 metres. I see no reason why Inmarsat should perform worse.
- In the first 2 hours of the flight MH370 was in range of two satellites (POR/IOR). During that time two intersecting lines of position should be available. From todays PMs Statement:
Today, based on raw satellite data that was obtained from the satellite data service provider, we can confirm that the aircraft shown in the primary radar data was flight MH370. After much forensic work and deliberation, the FAA, NTSB, AAIB and the Malaysian authorities, working separately on the same data, concur.
I.e. primary radar track and the positions from inmarsat correlate.
That is what gives them confidence in the data.
- What was shown to the public was only the
last known line of position. More lines from during the flight must be available.
- If sombody wanted to land that plane somewhere (I don't believe it) he might wanted to do that with first light. As we are close to Equinox the night/day border is almost parallel to the meridians. Longitude of the day/night border at 8:11 Malay time was somewhere close to the Andamans. Further west it was still dark.