I think that the transmissions from the airplane are time tagged, even without the data packets being transmitted. By comparing the ping time to the time on the satellite, one can tell how far away the ping is. You can draw a circle with that radius, taking into account fuel available on the airplane and last heading to sort of kind of bound where the airplane is. That is where the red circles in the NY Times article come from.
A second satellite is needed to pinpoint a more exact location, but even that will have a relatively position error on the ground. I don’t think it is within range of another INMARSAT. Whether or not other assets exist that could receive the signal is a matter of speculation. - KK6MC On Mar 16, 2014, at 2:01 PM, Rick Walter <[email protected]> wrote: > Tony, since the satellite cannot tell direction of the Ping, only distance, > the arcs have the same distance from the plane making up a half circle. You > would need to sats to hear the plane, see where the two arcs cross to > determine a location. > > This is the same way seismic stations locate earthquakes. > > Rick - WB3CSY > > Sent from Rick's iPhone 5 > "Great spirits have always encountered violent opposition from mediocre > minds" - Albert Einstein > > > >> On Mar 16, 2014, at 12:24 PM, "Anthony Japha" <[email protected]> wrote: >> >> Those so-called arcs that are said to be possible routes for the plane look >> much like the outer edge of one of the Inmarsat footprints. Is there logic >> behind the arcs or is it oversimplified nonsense? They are said to be the >> result of the signals Inmarsat received. But then why wouldn’t it be >> possible for the plane to be anywhere in the footprint? >> >> I’m sure many in our group have good ideas. I’m not trying to start a >> discussion of the entire mystery, only this one narrow, but possibly >> misleading, aspect related to our hobby. >> >> 73, >> Tony, N2UN >> LM 183 >> >> --- >> This email is free from viruses and malware because avast! Antivirus >> protection is active. >> http://www.avast.com >> _______________________________________________ >> Sent via [email protected]. Opinions expressed are those of the author. >> Not an AMSAT-NA member? Join now to support the amateur satellite program! >> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > _______________________________________________ > Sent via [email protected]. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
