Close... :-)
"We looked at the Doppler effect.
-PJ
Posted on 03/24/2014 10:34:25 AM PDT by don-o
Geostationary satellites are moving 1.91 miles per second.
I believe so. Makes sense.
Until they produce some evidence I’ll be standing by. It’s hard to believe any of these reports anymore.
I agree. I basically stated the same a week ago. Eventually something elaborated on the 'ping' at the time, but limited in detail.
It shouldn’t have taken this long. That it did seems suspect to me.
Doppler shift, since they compensate for it, should have been the 2nd thing they did after creating the 'arc' based on the 'ping'. You'd think, anyway.
Definitely odd that it took so long. However, much more plausible than overflying India to Pakistan with impunity and/or undetected...
There is a Monty Python sketch in here somewhere.
You're confusing orbital velocity with movement relative to the surface of the earth. That orbital velocity is designed to match the rotation of the earth so that, as much as possible, the satellite does not move relative to the surface of earth.
They are geostationary. Normally Low Earth Orbiting sats can track ground movement with radar using Doppler. Geostationary are 33,000 nautical miles out so this story may be wrong.
After this incident I am sure that they are going to beef up the system of satellite “pinging” to track aircraft. And probably remove the “off” button from all transponders.
Close... :-)
"We looked at the Doppler effect.
-PJ
This story has served its purpose as a diversion. Time to move along. Don’t question the authorities... they KNOW what is best for you.
If the plane runs out of fuel does it "glide" for a certain period of time or nose dive in ?
This story has served its purpose as a diversion. Time to move along. Don’t question the authorities... they KNOW what is best for you.
Plus, Richard Halibutron’s junk sailed into the ocean from China and was never herd from again.
There is definitely something out there
Inmarsats are comms satellites with focused spot beams. Wouldn;t that have to have been communicating with the plane to detect Doppler shift? If they had an orbital autotrack function that uses Doppler shift for orbital correction, the signal would be focused on a beacon with a known lat, long, and altitude. I thought satellites used star patterns in concert with ground beacons for navigation control.
No way an Inmarsat bird could “track” an object without common communications between the two objects IMO! Am I missing something here?
Signal Doppler can be caused by motion of the transmitter, motion of the receiver, or both. There would be little to no Doppler shift with regards to a satellite in geosynchronous orbit. Assuming that the satellite was near the same longitude there would only be Doppler shift if the plane were moving up or down relative to the surface of the earth, and hence, the satellite. If the geosynch satellite was near the horizon, a Doppler shift would only be generated based on the East-West motion of the aircraft. If the aircraft was on a mostly North-South track, as has been proposed, the Doppler shift would be VERY small.
If the satellite was in low earth orbit you could get significant up or down Doppler shift depending on positions and relative motion of the satellite and the aircraft. Doppler shift would be the greatest if they were on or near the same track and less or none if the tracks were perpendicular.
If the satellite had the ability to determine the bearing of the signal (unlikely) then you could use target motion analysis to generate a series of likely tracks (and general position) depending on the assumed speed of the aircraft.
Hope this helps.
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Right, Malasyan Triangle. It’s out there...
Assuming the pilot doesn’t push the stick “over” it will glide for miles, depending on your starting altitude and sink rate. The crew of a Canadian 767 had to dead-stick their jet into an abandoned CFAB base back in 1983, due to a malfunctioning fuel management system and poor “by hand” calculations. As a result, they took off with barely half the fuel needed for a flight from Ottawa to Edmonton.
The incident has become known as the Gimli glider, after the former Canadian AFB facility where they landed. It was also made into a fairly entertaining TV movie starring William Devane.
http://hawaii.hawaii.edu/math/Courses/Math100/Chapter1/Extra/CanFlt143.htm
Of course, the pilots of the Canadian 767 were trying to get their aircraft—and its passengers—on the ground in one piece, unlike the Malaysian pilot who flew that 777 into the Indian Ocean.
So what they are saying, in effect, is that they have zero idea where it actually is and zero idea what actually happened to it.
Someone alert CNN so they can go wall to wall with this for the next 200 years...
Maybe I’m being too much of a stickler here, but shouldn’t we wait until the plane is actually found before we start bragging about the technology’s success?
Just a thought.
Do you happen to know if the Auto pilot would automatically assume a glide path if the crew were comatose/dead and not in control of the aircraft. ?
It is definitely significant enough to be included in hand held GPS units -- error would increase significantly if it weren't.
This is so confusing to me..
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