Originally Posted by
JamesGBC
If they released the other pings and the last four are possible strait line. I'm sure someone by maths could work a possible track out.
The pings are time distances from the satellite and translated to an arc subtended from the point immediately below the satellite.
By definition these lines do not provide positions from which to drive a strait (sic) line. The lines will be a measurable distance apart. Let us assume they are at one hour intervals and are 200 miles apart; this gives a velocity vector of 200 mile/hr towards the statellite sub-point. You can then use a ruler marked off with the max ground speed, say 450 kts, and use this to fit the 450 mile marks to the arc. If you subtend this from the last know position it will give to a track at a given angle to the North with a similar mirror image to the South.
If you now mark the rule with either the minimum speed you can get another track which will be closer to the direct line to the satellite ground position.
You now have two sectors, one to the north and one to the south. The line joining the two points at the end of the sector arcs will give a possible line of position. These lines can then be plotted further on if it is assumed that the aircraft flew one for a time after the last ping. Only if you assume the
correct groundspeed would you have a discrete pair of tracks.
The closer together the ping arcs the greater the track angle would be to the north and south.
The logic only holds good if the aircraft made no course changes between pings and flew at a constant ground speed.