Free Republic
Browse · Search
News/Activism
Topics · Post Article

To: rodguy911

Rodguy911. Please reread the posting again. Take your time. Imagine 60+ satellites in orbit around the earth all evenly spaced. Each satellite can receive a signal from a 250 mile circle on the surface of the earth. As the satellite moves in orbit, the circle on the surface moves with it. Now imagine 60 other circles just like this also moving over the surface of the earth. As the 777 flys out over the Indian Ocean it is flying through these moving circles. The folks at Iridium Corp. know where each satellite is and has been. As the 777 flys out over the Indian Ocean it is flying through these moving Iridium circles. Each time the 777 pings, the Iridium folks can see the ping and know which satellite received the ping. Since they know which satellite recieved the ping and the time it received the ping they know where on the surface of the earth the circle is located. With one ping it is within the 250 mile circle. With multiple pings they can reconstruct a very accurate ground track. Hope that helps.


125 posted on 03/16/2014 8:22:02 AM PDT by robert14 (cng)
[ Post Reply | Private Reply | To 107 | View Replies ]


To: robert14
60 by 250 mile diameter circles doesn't cover the earth. 250 mile diameter circle has an area of about 50,000 square miles. The area of the earth is about 200,000,000 square miles.

That 250 mile circle is one of multiple "spots" viewed by each satellite. Each satellite can see (IIRC, from a post above) some 2300 mile diameter circle, which is covered by multiple "spots".

Your principle of being able to track is okay, the satellite network knows which spot(s) are getting signal, and can track signal motion across the face of the earth. Just a nitpick about how many 250 mile diameter spots are involved (many more than 60).

132 posted on 03/16/2014 8:32:07 AM PDT by Cboldt
[ Post Reply | Private Reply | To 125 | View Replies ]

To: robert14

A second confirmation is always better than the first.
What is your guess?Do they have multiple pings to work with? Can they refine the location to smaller than 250 square miles? What do you think. Having been there many times.Also let me ask you do many fellow pilots have simulators at their homes?Is that common?


135 posted on 03/16/2014 8:36:26 AM PDT by rodguy911 (FreeRepublic:Land of the Free because of the Brave--Sarah Palin our secret weapon)
[ Post Reply | Private Reply | To 125 | View Replies ]

To: robert14

Wow, dead reckoning and three LOP’s (lines of position) to build your ground track has really evolved. lol ;)


158 posted on 03/16/2014 9:07:47 AM PDT by Balata (Obama is a Lying Fraud, and so are his followers!)
[ Post Reply | Private Reply | To 125 | View Replies ]

Free Republic
Browse · Search
News/Activism
Topics · Post Article


FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson