Re: [time-nuts] MH370 Doppler (Magnus Danielson)
You can probably find links to all of the data from the Duncan Steel Blog.
You might start by looking at the questions the group has posed in an open letter to the ATSB and Inmarsat. Frankly, the data Inmarsat released appear to be rather scant and some believe to be doctored not RAW.
I applaud those applying their rather extensive math skills at this problem, but from the outside, it appears to me that the problem is so very complex (error prone) and so many assumptions are being applied, that folks time would be better spent scouring the beaches for flotsam from the aircraft to wash up.
But I could be wrong, maybe some time-nuttery will set them straight to an answer!
It still bothers me that with all the space, ocean and ground based radar, sonar and imaging sensors, there is so little trace of the aircraft's travels that night. Somebody must have seen something. In fact some observers have reported seeing stuff, fire in the sky, low flying aircraft and even a fire bottle washed up on the beach in the Maldives, but so much stock is being put in the southward arc, that nobody is listening.
"Does anyone has the set of timing and doppler measurements, and position
of the observing satellite?
Cheers,
Magnus"
--
Joe Leikhim
Leikhim and Associates
Communications Consultants
Oviedo, Florida
407-982-0446
In message 53F8060B.7020907@leikhim.com, Joe Leikhim writes:
I applaud those applying their rather extensive math skills at
this problem, but from the outside, it appears to me that the problem
is so very complex (error prone) and so many assumptions are being
applied, that folks time would be better spent scouring the beaches
for flotsam from the aircraft to wash up.
It's certainly a big problem that we're in tan(almost_ninety) territory.
As for debris on beaches, not so much. There's a gyre in the Indian
ocean which is likely to trap a lot of it.
It still bothers me that with all the space, ocean and ground based
radar, sonar and imaging sensors, there is so little trace of the
aircraft's travels that night.
The earth is pretty damn vast and not a lot of people loiter in the
indian ocean on the off-chance that a plane is going to ditch.
A very big uncertainty in relation to electronic tracking is that it
is pretty trivial to spoof another plane, and it has previously been
done by two planes carrying out a rendez-vouz and swapping squawk
and other identifiers over international water.
As far as I can tell, that would not work with the Inmarsat transponder
without physically swapping the radio modules. Given the hour-long
"off" period that could have happened, but it would have been so
much easier to just enable the squawk.
If they did a rendez-vous with a co-conspirator plane, took
over their squawk code, turned off livery-lights and followed
the prefiled flightplan, MH370 could fly unchallenged by all
airforces all the way to the Black Sea along the norther route.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Joe,
I did find it here:
http://www.dca.gov.my/mainpage/MH370%20Data%20Communication%20Logs.pdf
There is also some Inmarsat presentation giving a little more detail.
At the same time, the data gathered is from a system not designed for
navigation and positioning purposes. It gives a rough hint. The reported
resolution of the time and doppler and the checking time all gives that
indication. The ring of last communication is from the time observation,
and the reduction of that ring to likely sectors is due to doppler and
time observations in previous observations trailing back to known
position. Not very good hints. It's a system that only after the fact
became a positioning system.
Doppler positioning is indeed possible, but that requires more
continuous observations than once every hour.
I think that the Inmarsat folks most probably did about as much as you
can with the data at hand.
The BTO jumps in 20 micro steps. That is 6 km of satellite-plane
distance, which through geometry becomes wider as the angle from the
satellite-earth-line increases. Good enough hint for a search party, but
the lack of frequent "pings" only shows in what neighborhood to search.
Making some assumptions on continuous flight path helps.
The BTO jumps between different types of channels, so only R-channel is
being used for estimates.
This positioning problem isn't very complex, but is a good exercise as
it is similar to the pseudo-range measurements and positioning from GPS.
The doppler and time observations with some basic geometry gives most of
it out. The systematic doppler shift needs to be canceled but there is
base measurements included that helps with that.
Cheers,
Magnus
On 08/23/2014 05:10 AM, Joe Leikhim wrote:
You can probably find links to all of the data from the Duncan Steel Blog.
You might start by looking at the questions the group has posed in an
open letter to the ATSB and Inmarsat. Frankly, the data Inmarsat
released appear to be rather scant and some believe to be doctored not RAW.
I applaud those applying their rather extensive math skills at this
problem, but from the outside, it appears to me that the problem is so
very complex (error prone) and so many assumptions are being applied,
that folks time would be better spent scouring the beaches for flotsam
from the aircraft to wash up.
But I could be wrong, maybe some time-nuttery will set them straight to
an answer!
It still bothers me that with all the space, ocean and ground based
radar, sonar and imaging sensors, there is so little trace of the
aircraft's travels that night. Somebody must have seen something. In
fact some observers have reported seeing stuff, fire in the sky, low
flying aircraft and even a fire bottle washed up on the beach in the
Maldives, but so much stock is being put in the southward arc, that
nobody is listening.
"Does anyone has the set of timing and doppler measurements, and position
of the observing satellite?
Cheers,
Magnus"