Originally Posted by
oldoberon
About 8 pages back EPPo posted today's update and says they had 6 pings that is basically 1 an hour after falling of milrad.
Please follow me through this.
If you look at the map by Volcanicash page 203 #4043 (
http://s8.postimg.org/ye87yekz9/isat.jpg )
Counting back that is 40, 45,50,55,60 65. He clearly could not have gotten that close to the centre of the elevation rings ,and still get to those final arcs, so he must have flown at tangent to them, My best guess is
1st ping 45 - west bound from final radar loss point
2nd ping 50 still west ish bound
3rd ping 55 still west ish bound
he then turns NW or SW
4th ping 50
5th ping 45
6th ping 40
and ended up on the north or south arc.
But there was a rush to the north (Andam sea) why?
Finally if you look at this link from Vinnie_boombatz p201 #4011
http://telecom.esa.int/telecom/media...-Obj4-hres.jpg
It shows the beaming arrangement of the I-4 series inmarsats (3 cover the world), there is wide beam (the whole area), a number of regional beams and finally the narrow beams. ( used I-3 diag for explanation purpose only)
To my knowledge the signals were picked up by the old I-3 sats which use 4 to cover the world and only have wide and regional beams.
As I understand the workings of the system the sat send a "hello anyone there" signal using the wide beam and if a reply is received it calculates the best regional beam to use transmits back to the response using the regional beam. Sat engineers pls confirm/correct.
The point of this post is to ask an expert if it can do that why don't we know a more accurate position ie a shorter arc based on the regional beam.
yes it is my own post from late night early morning but still hoping satellite savvy person can confirm because it would tell us it is possible to significantly shorten the arcs. MY hypothesis below could rule out the northern one
CAN PINGS GIVE CONFIRMATION OD A CONSTANT HDG ( not the actual hdg)
Most of the investigators work seems to assume a constant speed (presumably based on distance between pings.
The following assumes the rings shown are just the five degree rings for clarity ie they not fixed aerials on the satellite but dependent on aircraft position and all others are possible ie 51,52,53,53 etc
If you used this speed and assumed at any previous ping the aircraft crossed 1st ring at 90 deg, then you can calculate at which ring the next ping should occur at, if it is less than this radius , you should be able to using this difference calculate the angle at which he crossed the second ring to give this reduced distance ( ie actual distance traveled is the same but not at 90 deg to 2nd ring. If following pings show the same ring spacing he is on a constant track. You will not know where on the arc he crossed it or the hdg.
If plane on a constant track I would suspect heading south because north would certainly end up with a contact on radar unless evasive action taken.
Any maths folk out there who can confirm this is a valid idea.