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Sticking My Nose (As Usual) Where It Does Not Belong

INMARSAT has passed the following to those engineers working the Flight MH-370 signal intercept issue.

If the precise frequency of the MH-370 transmissions is known, and compared with
the intercepted value, you can, by applying the cosine values of estimates for
the offset angle from the location of the satellite to the assumed course of
flight MH-370 (180), approximate speed.

Depending on the accuracy of the intercept time, you can do the same thing and
derive a position if you have three satellites involved. You also may be able to
do that by using sequential intercepts by one satellite at different positions
along its orbit if you calculate and correct for the changing position of the
satellite.


Will advise if there is any response.

Re: Sticking My Nose (As Usual) Where It Does Not Belong

It seems to me that even with both the aircraft and (single) satellite moving, there should be calculations that would at least indicate aircraft direction of movement if not a fairly precise course (actually an MB solution). Calculations of doppler should be able to estimate "relative speed" between the aircraft and satellite, and since the speed of the satellite is known, the aircraft speed should be a pretty accurate calculation.

Am I dreaming, or over-thinking this?

Re: Sticking My Nose (As Usual) Where It Does Not Belong

George:

I agree; there appears to have been an "under-exploitation" of the Doppler data. (See quote below).

The critical point is: how stable (repeatable) and how narrowband was the frequency of the signal sent by MH370?

Quote: In a press statement this afternoon, Prime Minister Najib Razak said that, using a type of analysis "never before used in an investigation of this sort", Inmarsat engineers have been able to establish that the plane's last position was in the middle of the Indian Ocean, west of Perth.

Re: Sticking My Nose (As Usual) Where It Does Not Belong

Stability could well be a problem, but quite honestly, I think that the bandwidth of the freq could be handled. I also would expect that such a signal from a modern a/c would be pretty stable. I just don't know. But I suspect that you are right on in your assessment that there could be more exploitation than there appears to be (based upon the notion that this is indeed a type of analysis (never before used).

I also do not have confidence in the Malaysian govt, and we also do not know how much "insightful" information is being relayed to the Malaysians.

Why are you still awake? A good way to combat your wx is to take a stout one and crawl under the blankets.

Re: Sticking My Nose (As Usual) Where It Does Not Belong

I just caught a few minutes of the Sean Hannity show, and his guest was a Brit that seems to know what he is talking about. He indicated that the INMARSAT satellite is "geostable", which is essentially stationary.

His explanation of the new analysis was doing simple time delay calculations (satellite inquery - a/c response) over a number of points in time. While this seems logical, I would hardly regard it as new thinking or something never before done.

Re: Sticking My Nose (As Usual) Where It Does Not Belong

Ha! As I read this string between Bruce and George I am imagining the two standing over a wooden, tilting, lighted plotting table with rows of Sonar Data Recorders clicking in the background. Both are holding coffee mugs - George is pointing at the plot while Bruce is scratching his head......... Ah, the memories.

Re: Sticking My Nose (As Usual) Where It Does Not Belong

George:

It would appear time to install a tamper-proof interrogate and respond system (a transponder) on aircraft and, if such already is the case, as I strongly suspect, use it on a regular basis.

Such systems work on spacecraft at ranges of multiple billions of miles with a range errors of less than 10 miles.

Re: Sticking My Nose (As Usual) Where It Does Not Belong

Bruce:
Thoroughly agree. But I think it odd that something like this isn't already in use. Tamper-proof to be certain. Mount is on the outside of the fuselage with NO internal kill switch. Probably be a good idea for it to have a totally independent power supply (also mounted outside the a/c skin). Perhaps each aircraft could have a unique signal/frequency/pulse that is assigned and built in to the airframe at manufacture.

Satellite tracking routines would automatically know the "who" and the "where" on a continuous basis. Lets really get complex. Perhaps the flight plan could be digitized and available for real-time correlation. Deviations beyond an established baseline result in instant alert signals to the airline or whoever else might need it.

No longer depending on radar with its limitations, or on a sleepy controller in the middle of the night, or on "dead zones", or successful tower handoffs; just a satellite keeping ever-vigilant.

Aren't we already doing something like this? Please tell me we are.

Re: Sticking My Nose (As Usual) Where It Does Not Belong

George:

If we are doing something like what you suggest, I have not heard squat about it.

Does anyone on this site have the connections to bring this matter to the attention of the proper authorities?

It seems almost criminal that the capabilities you describes are not in existence.

Bruce

Re: Sticking My Nose (As Usual) Where It Does Not Belong

You know Bruce - if we WERE doing something like this, there would never, ever be a 2+ week period where the world didn't know where an aircraft was located. There is only a limited amount of time for survivors clinging to a life raft, or worse yet, bobbing on the surface wearing a life vest. So a system isolated from in-air manipulation could be critical for personal survival.

I have to conclude that there is no system in place that functions in a manner that we are talking about.

The descriptions I'm hearing about the way INMARSAT communicates with the aircraft is that there are only "periodic" inquiries, and for sure the system can be turned off from within the aircraft.

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