Wow, dead reckoning and three LOP’s (lines of position) to build your ground track has really evolved. lol ;)
Hello Balata. It is more the DR. There is one assumption you have to make about the ground track while the pilot was flying over the Indian Ocean. He flew in a straight line. Using my KISS rule. If you layout 6 Iridium satellite circles on the surface of the earth that correspond to the 6 pings and try to overlay a straight line thru them you should be able generate a fairly good ground track. That is not dead reckoning.
If he flew multiple random headings we will never find the airplane.