Hi Antonio:
It's my understanding that the satellite sends a ping to each aircraft in it's low gain antenna pattern once every hour
by aircraft ID number.
The aircraft replies with a very short data packet that's time stamped (but without any location or other info other
than the ID).
The difference between the time stamp on the ping and the received message is
the ping time.
The idea is to have some idea which of the spot beams to use if someone on the
plane wanted to make a phone call.
As it happens MH370 does not have first class or sat phones, but this is the
default system for everyone.
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
[email protected] wrote:
----Messaggio originale----
Da: [email protected]
Data: 20/03/2014 1.47
It depends on how accurately the bird can measure the round-trip time:
1 us = ca 500'
10 us = ca 1 mile
100us = ca 10 miles
1 ms = ca 100 miles
The arcs are loci of constant round trip time, projected on the globe.
This is valid for round trip and for the signal path which in this case is the
line generating the cone having the bird at its apex. The radius of the circle
at earth is another thing, and the error should be multiplied by some factor
which depends on the angle at the apex, being the earth's surface curve. Hence
I tought that the timing is crucial. Add to this that I understood it was not a
ping as we usually mean, but a one way signal (aircraft to satellite). Hence my
question.
Antonio I8IOV
-John
===============
My question was on what would be the expected accuracy of the circle's
radius.
Antonio I8IOV
----Messaggio originale----
Da: [email protected]
Data: 20/03/2014 1.21
They only got one ping from INMARSAT at 64E above the Indian Ocean.
There was no other ping to triangulate the position.
One ping projects a circle on the Earth. The maximum flying range of the
plane determined the ends of the NE and SE arcs of that circle.
The news only gets stranger as time goes on.
Bill Hawkins
-----Original Message-----
From: [email protected]
Sent: Wednesday, March 19, 2014 6:46 PM
Those who say the missing aircraft should be searched along the two
corridors, what measurement are they relying on? I think it is a one-way
measurement of time-stamped pings, which implies good synchronization of
clocks between a geosynchronous satellite and a moving aircraft. Antonio
I8IOV
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
