Malaysian Airlines Flight MH-370 goes missing

A_Gupta · Post by **A_Gupta** » 25 Mar 2014 03:26

matrimc wrote:[
Also the picture Theo posted why do the coverage areas look like rounded rectangles rather than ellipses or circles?

I believe those curves are the lines where the satellite is 5° above the horizon. Why are they so distorted? The joy of a Mercator projection?

UlanBatori · Post by **UlanBatori** » 25 Mar 2014 03:30

Ramana: Since GEO spots are highly coveted, they always try to minimize cross-talk between satellites, I would think. This may be the reason that coverage regions are shorter along the width and longer sideways: antenna shaping, probably. Actual regions may look like a lot of lobes etc.

Also, it is quite possible that the real occurrences are known to certain saterrites who hired PakMarSat to give the press announcement and claim credit for it. Doppler etc is plausible, not necessarily how whoever found out whatever. I bet it was PakSat-1R that REALLY found the plane, they are just too modest to reveal this.

The INMARSATs are by no means the only GEO saterrites looking down on the IO region... at other frequencies. Plus all the Polar and sub-sync and equatorial saterrites. Overall there are thousands, hain?

Vayutuvan · Post by **Vayutuvan** » 25 Mar 2014 03:59

Theo_Fidel wrote:Matrimc,

IME Companies like INMARSAT don’t mess up stuff like this. Their commercial lives are on the line.
I suspect it may have something to do with the antenna and receiver design. You often see these odd cell coverage maps based on the Antennae .

Theo

This is mere marketing collateral for the web pages. I bet they have more accurate maps and other detailed info for people who deal with them at a technical level.

Another could be that there is a cutoff at some latitude - say arctic and antarctic circles above and below which data is not collected though the area is illuminated. How can one stop illumination exactly at the boundary where the arctic circle starts?

So it is a combination of simplifying for presentation on the web plus what svinayak had said - no customers in those areas (near the poles).

Harpal Bector · Post by **Harpal Bector** » 25 Mar 2014 04:02

1.6 GHz carrier will experience a fractional redshift of 7e-7 for an ac moving at 540 kts directly away from the sat.
MH370 was moving at close to 90 deg to satellite this would make the fractional redshift closer to 6e-8.
To get that redshift measured properly you would need a clock that was stable to 6e-10.

To measure the freq of carrier they will sample at 4x the rate 6.4 GHz. I dont know what the width of the ping is but say it is 10ns (about 10 cycles of averaging before it locks in), so over that time the reference clock used for the lockin measurement will be stable to 6 parts in 1e10.

That looks like a desired Allan variance of 1e-14 per sqrtHz. IIRC the NIST time stamps have that kind of stability over 10nsish timescales. I dont know if the time stamps on the INMARSAT oscillators are all referenced to the NIST clock and to what extent the relative errors are understood.

It used to be that the mil grade GPS sats were matched to the NIST clocks and were good at 1e-11 per sqrthz level. This was a decade ago, maybe things are
better now?

Vayutuvan · Post by **Vayutuvan** » 25 Mar 2014 04:02

UlanBatori wrote: I bet it was PakSat-1R that REALLY found the plane, they are just too modest to reveal this.

Or the controllers of the PakSat-1R satellite were "gubo"ed in private and they revealed what the satellite had seen with its own eyes.

TSJones · Post by **TSJones** » 25 Mar 2014 04:34

And don't forget Einsteins Special Theory of Relativity. Time is not the same for a satellite as it is on earth so corrective calculations must be made like they do for the GPS satellites in order to get the correct measurements. Uh, cough, cough.

Vayutuvan · Post by **Vayutuvan** » 25 Mar 2014 04:38

From wiki entry on Atomic Clocks

Evaluated accuracy[edit]

In 2011, the NPL-CsF2 caesium fountain clock operated by the National Physical Laboratory (NPL), which serves as the United Kingdom primary time and frequency standard, was improved regarding the two largest sources of measurement uncertainties — distributed cavity phase and microwave lensing frequency shifts. As of 2011 this resulted in an evaluated frequency uncertainty reduction from 4.1 x 10−16 to 2.3 x 10−16 — the lowest value for any primary national standard so far.[27] At this frequency uncertainty the NPL-CsF2 is expected to neither gain nor lose a second in more than 138 million years.[28][29][30]

By the by, numerical zero in a double precision (64 bit IEEE standard) would be of the same order of magnitude ~ 1.0e-16 (or even a little larger 1.0e-15). One would have to compute with double double (128 bit reals) for getting that kind of accuracy. NIST has shown an (relative) accuracy a second in over a billion years which works out to ~ 3.1709791983764588e-17 in 2008. Question is whether it has been commercialized and anybody is employing this tech? After all 5 years have passed.

Vayutuvan · Post by **Vayutuvan** » 25 Mar 2014 04:48

TSJones wrote:And don't forget Einsteins Special Theory of Relativity. Time is not the same for a satellite as it is on earth so corrective calculations must be made like they do for the GPS satellites in order to get the correct measurements. Uh, cough, cough.

Isn't frequency shift a relativistic effect and that's what is being measured? Since the distances over which one has to be measure the shift is small in this case, the relative clock accuracy would be crux of the matter (energy

hat-tip to Nijalingappa garu).

vina · Post by **vina** » 25 Mar 2014 04:51

Harpal Bector wrote:If they do that and it checks out then I am willing to believe that SB route is the most likely path of the ac.

The SB route would not necessarily imply "the flight ended over water", there is still the mystery of why there was no detection by either Indonesian radar or by Aus radar on Cocos Island. The Malaysians may be jumping the gun.

How so ? All that will let you conclude that the plane could have flown that trajectory either north OR south. You cannot eliminate the north route from Inmarsat data alone. You will have to take the Indians on their word that that the plane didn't fly across Indian territory, including Andaman.

The SB route and no radar track in Andaman is not so perplexing. Whoever programmed the plane knew exactly what they were doing and made it fly a track between radar coverage areas . That is why it flew in the isthmus over Thailand/Malaysia, turned NORTH on the civil route to a marker towards Andaman, and would have then cleared the tip of Sumatra and then turned SOUTH to fly down Indonesia's west coast straight down to the splash point in the Indian ocean. The track in the pictures are misleading. Each of the pings would have been roughly in the concentric circles inside. The red arcs were the outer limits. From the last position, across from the inner arcs to the outer one on a roughly straight / great circle line I suppose.

Now, if the Inmarsat signal is received by more than ONE satellite , say two (for eg, the IRS series have an emergency beacon locator) , then you can obviously triangulate and clearly get even the altitude. But here too, the symmetry of the problem means that you cant eliminate the northern track, unless you take the Yindoos on their word, or okay, if 3 satellites get the signal, then you can nail it exactly to the southern track.

vina · Post by **vina** » 25 Mar 2014 05:03

matrimc wrote:Isn't frequency shift a relativistic effect and that's what is being measured? .

Yes. But this doppler theory (as CNN and BBC claim it is being used, probably being dumbed down for the mass audience) doesn't pass the smell test.

Tell me this. Which radio system that you know of for the purpose it is being used like Inmarsat, actually RECORDS the frequency at which it received the signal and stores it (remember, this tracks thousands of flights and ships and operates in space, it will run out of memory very soon) , for the folks who did that analysis to be able to go and analyze doppler shifts! My understanding , subject to correction is that the Inmarsat system is just a plain radio like system that receives and transmits data. It is not a radar like system that looks to calculate speed and heading and location.

To keep that in perspective, even the specialized system designed explicitly to find and record speed, heading and location, namely GPS and it's multiple avatars (Glonass and the Euro and Chinese stuff) use time delay of arrival and NOT doppler shifts. Time delays are far simpler, cheaper and easier than use frequency shifts.

ramana · Post by **ramana** » 25 Mar 2014 05:09

Vina you have hit upon the bokwas in the doppler theory. Most likely they have some other info and are pulling wool over the gullible public.

UlanBatori · Post by **UlanBatori** » 25 Mar 2014 05:12

UBCNews presents:

A totally hypothetical story

Person A decided to steal an entire jetliner and make it disappear. Let's not worry WHY, but consider the planning.
1. Exactly between handoff from Malaysia ATC and receipt by Vietnam ATC, and right after an engine data ping, the ACARS was switched off. The transponders were switched off. Maybe the lights were switched off.

Now the "legend" created:
a. The plane dropped altitude below radar, and turned around 90 deg. Headed straight over sea lanes to prevent anyone calling on their cellphones. Skirted Thailand border: forested areas.

b. Climbed back up to cruise altitude. You can't fly to the other side of the planet unless you are cruising at a decent altitude at a well-planned speed. Weather was not great in these regions at low altitudes.

Now my question: Given the planning and technical knowledge that went into this plan, was A so stupid that s(he) allowed the plane to respond to PakMarSat Pings??? I say that this is a very dangerous assumption, 99.99% probably wrong. Assume it is wrong.

2. The ping responder is not a reflection like radar. It is a digital gadget that receives a ping, thinks about it, and gives a response. That response, like anything else, could be programmed.
With a variable response delay (read the INMARSAT gloat carefully: they mention that on average, the plane was moving away from the satellite, IOW, sometimes it was NOT moving away from the satellite. Why would an unpiloted craft drift randomly in direction?)

3. So... the Ping Responder was also controlled. Ultimately, it provided "confirmed" evidence that the plane was moving along southward to the middle of the deepest and most remote part of the Ocean on the planet. And then stopped responding.

ALL of these could have been done with a transponder that was actually sitting in Kuala Lumpur, or on a container ship anywhere in the listening range of the INMARSAT/PAKMARSAT.

The perfect crime. Exquisitely successful so far.

"All the King's horses and all the King's men
Couldn't put Humpty-Dumpty together again".
Or figure out where the plane was taken or what was done to it.

UlanBatori · Post by **UlanBatori** » 25 Mar 2014 05:24

vina: not ruling out the bakwas, but...

RECORDS the frequency at which it received the signal and stores it

Doesn't have to do that. Just needs to store the pulse length as one word (64-bit?) They need that to confirm that it was indeed a valid ping return. There must be something in the ping return that identifies the aircraft.

For instance, a laser Doppler velocimeter puts out digital data. Each time a micron-sized seed particle transits the measurement volume, one digital word is put out: it gives the time for N fringe crossings (cycles of a sine wave) as a 16-bit word. This time used to be the output of a 500 MHz clock with 4 phase values possible. And the time since the previous data value as another 16-bit word that includes some other info. A single "measurement" may be 100,000 such data pairs. Hundreds of those might be taken in an hour. The storage needed is trivial, we used to do this with 1980s Hewlett-Packard minicomputers in Ulan Bator. Modern PCs can do orders of magnitude better; the whole thing can be programmed in software, because clock speeds are several GHz.

ramana · Post by **ramana** » 25 Mar 2014 05:30

UB, Dont you have access to good avionics gurus in Mangolia?

UlanBatori · Post by **UlanBatori** » 25 Mar 2014 05:33

I am sure there are many in Mangolia, even the yaks go around with blinking tails, but not smart enough to appreciate good CTs.

Confirmation from kindergartners that their part-time jobs involved processing data files coming in from engines. E.g., (over a week ago) "if that plane had landed, I would have seen a vibration reading from the engines".

A_Gupta · Post by **A_Gupta** » 25 Mar 2014 06:13

^^^ I am willing to believe that a radio signal from a plane 36000+ kilometers away is going to be rather weak, and to keep noise from overwhelming signal, the satellite receiver will want to put a very narrow-band filter to isolate the signal. Obviously, this filter needs to be tunable in its pass frequency so that things like Doppler shifts and such can be taken care of; what I find incredible is that someone would record how the pass frequency moved in a given transmission.

On the other hand, engineers can be anal; and given practical experience that the time between when you stopped recording/keeping data and the time that you now really need it is a week or less, maybe they record everything.

The second puzzling part is - why do planes heading south have a different Doppler signature from planes heading north? All that should matter is speed and heading relative to the satellite.

krisna · Post by **krisna** » 25 Mar 2014 06:13

read the whole dhaaga--

have this question--
why would anyone send some contraband bilogical or nuclear or something deadly in the passenger plane. are there not adequate safeguards to protect common people.
isnt it too risky as there aare many people mucking around the plane.

In fact better to take in private jets/planes military or non military etc

anyway noobie in these matters.

UlanBatori · Post by **UlanBatori** » 25 Mar 2014 06:27

Guptaji:
1. The frequency is recorded as a time for N cycles. There is a thingy called a Schmitt Trigger which starts a switch when a signal goes above a certain level, and counts zero crossings, until N such have occurred. Then it switches off. The time elapsed is compared with the master clock, to catch the number of clock ticks that have elapsed. The clock runs at several GHz, depending on the saterrite's basic frequency.

It may be that the nominal pulse length has something to do with IDing the plane, so it may be standard practice to record the time count. All they did is go and look at the precise number of nanoseconds to capture the Doppler shift. It may well be that the pulse width is on the order of microseconds, so counting in nanoseconds or sub-nanoseconds, is overkill.

2. See Harpal's brilliant insight above: the acceleration due to Coriolis effect has a different sign for an object traveling north vs. traveling south.

shiv · Post by **shiv** » 25 Mar 2014 06:40

Theo_Fidel wrote:Isn't it telling that only one of the INMARSAT satellites picked up the plane.

Here is the Map of INMARSAT coverage for reference. Note the gap between AOR-E & POR.

From this pic it seems like India, Vast areas of Russia, Indian Ocean, Pacific ocean and central parts of US are covered by one satellite onlee. Western Europe has 3 sat coverage. Poles and parts of Canada - over which lots of planes fly have no coverage
. But heck - they are MARitime saterrites.

UlanBatori · Post by **UlanBatori** » 25 Mar 2014 06:42

Vely hald to covel bores with saterrite above equatol.

vina · Post by **vina** » 25 Mar 2014 06:48

UlanBatori wrote:For instance, a laser Doppler velocimeter puts out digital data. Each time a micron-sized seed particle transits the measurement volume, one digital word is put out: it gives the time for N fringe crossings (cycles of a sine wave) as a 16-bit word. This time used to be the output of a 500 MHz clock with 4 phase values possible. And the time since the previous data value as another 16-bit word that includes some other info.

UBJi. You and I are talking of different animals. You are talking of speed finding Yaks where you use light in Mongolia to measure doppler shift , with an id that ensures that what you are smelling is your own Yak's dropping and not your neighbor's Yak's, while in Texas with Longhorns, they use radio waves to do the exact same thing. But notice, that you dont need to store the actual frequency you received the signal. That can be easily calculated back from the data . Knowing the freq you transmit at and with your result (target is coming towards you or receding from you), you can calculate the receive freq, so no need to store, and I doubt you will. Anyway, distance is by pulsing and using echo location onree, whether Yaks do it or Longhorns do it.

Again, coming back to different animals, the ACARS I think is a data system that basically sends data back to Boeing and engine makers, data details, say part X saying, I got my 72 after getting 100bars of vacuum eggsplosion, I doubt it will be like a radar system where you shine and examine the returns, but rather an IT/Vity data system which is a transmit only system (no need to receive), where some data packets are sent on a one way ticket to their jannat either to Boeings database or RR /GE/PW databases or both after an initial handshake which confirms if the transmitting system is actually Abdul Lungi or not. Such an IT/VITY data packet system will have no need whatsoever to examine frequency shifts first and even if it did, wont store the actual frequency (must be absolute value) for you to do analysis on later. For eg, your wireless modem will not be storing the actual frequency at which it received the signals if you walk around with your iPad/iPhone in the WiFi mode.

That is why I think this published info of doppler shifts from failed attempts of ACARS to connect to inmarsat doesn't pass the smell test.

A_Gupta · Post by **A_Gupta** » 25 Mar 2014 06:56

I think the Coriolis force acceleration would be way below the threshold of detection.

vina · Post by **vina** » 25 Mar 2014 06:56

UlanBatori wrote:2. See Harpal's brilliant insight above: the acceleration due to Coriolis effect has a different sign for an object traveling north vs. traveling south.

I might be missing something here. But all there are fixed wrt to earth. The plane is not like a free body like say a cannon ball for you to detect the velocity shift due to the corilios force for it to show as differential readings on the satellite via doppler shift. The plane is actively being steered by autopilot to fly a constant speed course wrt to the earth's surface, whether flying north or south. I doubt that will show up as a doppler shift for you to detect. I do think you will need the Yindoos to swear on the Bhagvad Gita to rule out the northern course if you are relying on doppler shift alone to determine location.

member_28502 · Post by **member_28502** » 25 Mar 2014 07:09

the distances are not astronomical to have Doppler effect

page 27-11 gives most of the answers except Mongolian Yaks droppling effects

http://tinyurl.com/ljoqn29

it also explains why at the polar regions the Geo stationary sat coverage has flat (like square wave horizontal chop instead of sharp ellipsoid shape)

Inmarsat plc (LSE: ISAT) is a British satellite telecommunications company, offering global, mobile services. It provides telephone and data services to users worldwide, via portable or mobile terminals which communicate to ground stations through eleven geostationary telecommunications satellites.

so the image of possible signal trace was from Geosat not polar sat which are more accurate for polar regions....

shiv · Post by **shiv** » 25 Mar 2014 07:20

UlanBatori wrote:Vely hald to covel bores with saterrite above equatol.

Arso convenientry, untir grobar walming takes hord, no ocean at bores fol Inmalsat.

UlanBatori · Post by **UlanBatori** » 25 Mar 2014 07:31

The plane is actively being steered by autopilot to fly a constant speed course wrt to the earth's surface

Well.. maybe it is and maybe it isn't. If it is flying on with no autopilot, just manual stability, with the engines running merrily on at last setting, what Harpal says is possible. Coriolis acceleration may not be negligible: distance is large, and velocity is large. The claimed path is nearly perpendicular to the direction of Earth's rotation.

But all said and done, I am wondering if anyone who was evil enough to fix the ACARS and do all those things with malice aforethought, wouldn't also have fixed the transponder that talked to INMARSAT. I say that the INMARSAT readings were also fixed. Not by INMARSAT, but by whoever sent it. IOW, I could be lolling on my hammock in the Maldives, adjusting the pulse times on my INMARSAT-spoof module, and

thinking about all the Peer Review Groups and Red Teams with smoke coming out of their ears in Bilayat, computing Average Path of MH370.

UlanBatori · Post by **UlanBatori** » 25 Mar 2014 07:42

See: reality is beginning to sink in, even at See Enn Enn:

There's no winning when it comes to flying a turbofan-powered airplane: If you want to fly far, you need to fly high.

So the fuel required for MH-370 to have reached the presumed crash location around 1500 miles west of Perth, Australia, means that the airplane did not do a lot of climbing or descending after it deviated from its original planned route to Beijing while it was still an hour or so north of Kuala Lumpur.

So if there was a struggle for control of the flight -- whether it was mechanical issues or a hijacker -- it could not have lasted long or involved great altitude deviations.

This means it's hard, though not impossible, to explain the disappearance as being the result of a mechanical or electrical failure. Such a scenario, as I've been saying since the beginning of the mystery, would require a kind of mechanical magic bullet, an event that would have taken out the transponder and ACARS radio, as well as the voice communications radios. Why else would they not have communicated the emergency?

Then one must accept that such a failure chain could then allow the crew -- or skilled intruder-- to be able to drive the airplane around the sky for a protracted period of time, eventually pointing it south, in the opposite direction from where the airplane was originally headed.

Let's remember, too, that the airplane would have to maintain an altitude sufficient to allow it to reach the southern Indian Ocean. All this must also have left the 777 in good enough shape to fly for another six hours or so before crashing.

A failure of the pressurization system might account for the scenario, but only if the pilots completely mismanaged their response to the emergency. The 777's backup and emergency oxygen systems are just as intelligently designed as the rest of the jet's redundant systems.

It's also difficult, if not impossible, to explain how the jet could have made the turns it did if the crew were unconscious during that time. Were they desperately trying to find an airport before time ran out? If so, they would have done two things they didn't do: They would have communicated the emergency and they would have descended. Neither of those things happened.

While it's horrific to imagine, a botched hijacking or failed pilot commandeering of the airplane are still the most likely scenarios.

BUT.. he's not taking that next logical step: Someone smart enough to fix the ACARS and voice comm and take over the plane and fly a complex set of maneuvers precisely, is also going to spoof the INMARSAT to make them think you flew towards the South Pole. When you are lolling in LaHore or Male, or maybe Mogadishu. Or Beijing? No, can't be.

UlanBatori · Post by **UlanBatori** » 25 Mar 2014 07:43

And.. note that another day has passed, and none of those reported pieces of wreckage has been seen again, much less retrieved.

A_Gupta · Post by **A_Gupta** » 25 Mar 2014 08:37

And after today's bad weather, it is even more unlikely that they will find anything.
Via an AMSA link
https://www.amsa.gov.au/media/

25th March, 2014: 9.45 am
(AEDT)

Search operations suspended for today due to adverse weather : Update16

The Australian Maritime Safety Authority’s search for any signs of the missing Malaysia Airlines flight MH370 has been suspended for today due to poor weather conditions in the search area.

Due to rough seas, HMAS Success departed the search area early this morning and is now in transit south of the search area until seas abate. A sea state ranging between 7 to 8 is forecast today with waves up to two metres and an associated swell of up to four metres.

The area is also forecast to experience strong gale force winds of up to 80km/h, periods of heavy rain,
and low cloud with a ceiling between 200 and 500 feet.

AMSA has undertaken a risk assessment and determined that the current weather conditions would make any air and sea search activities hazardous and pose a risk to crew. Therefore, AMSA has suspended all sea and air search operations for today due to these weather conditions.

AMSA has consulted with the Bureau of Meteorology and weather conditions are expected to improve in the search area in the evening and over the next few days. Search operations are expected to resume tomorrow, if weather conditions permit. HMAS Success will return to the search area once weather conditions improve.

Last night, HMAS Success attempted to locate objects sighted by a RAAF P3 Orion aircraft. The objects
were spotted visually in the search area by the RAAF P3 Orion about 2.45pm (AEDT). Drift modelling was undertaken to assist search efforts. HMAS Success was unable to relocate the objects.

In light of the statement by the Malaysian Prime Minister Najib Razak overnight, AMSA offers its deepest sympathies to the families of the passengers and crew of flight MH370. AMSA intends to recommence search activities for any signs of the aircraft once weather conditions improve in the search area.

member_28502 · Post by **member_28502** » 25 Mar 2014 08:41

In the mean time this song should be dedicated to Yak herding Farmers of Mongolia

ramana · Post by **ramana** » 25 Mar 2014 09:07

CNN says Aussie MOD to talk in a few minutes.
Malay PM to speak soon after.

anishns · Post by **anishns** » 25 Mar 2014 09:11

UlanBatori wrote:See: reality is beginning to sink in, even at See Enn Enn:

Bliss to watch!

http://www.frequency.com/video/was-mh37 ... 50/-/4-895

Aljo pay attention to 3:20 argument between Bartania babu and Amreeki babu.
Bartania babu claiming that Bartania equivalent of NTSB has much better reputation than Amreeki NTSB!

vina · Post by **vina** » 25 Mar 2014 09:25

A_Gupta wrote:^^^ I am willing to believe that a radio signal from a plane 36000+ kilometers away is going to be rather weak, and to keep noise from overwhelming signal, the satellite receiver will want to put a very narrow-band filter to isolate the signal. Obviously, this filter needs to be tunable in its pass frequency so that things like Doppler shifts and such can be taken care of;

Ok. I will buy this . The receivers in stuff like cell phone towers must be tunable and locked to precise frequencies to be able to receive from multiple channels and also to be able to receive from moving vehicles and the doppler shifts. You can make cell phones from airplanes , so it is good enough for airline speeds. Inmarsat will have such stuff as they facilitate making calls from airplanes. Maybe that info is dumped into the logs and call metadata for billing and other purposes (you called on this frequency for this many minutes to this mohtarma, so pay x no of goats as baksheesh).

Yes, now if you can get info from Boeing on exactly what is the time period between expected pings, compare it when it came, and from the frequency at which you listened to the pings, you will get the distance from satellite to plane, and the velocity of the plane at those instants, and you can get a reasonable track and trace on the ground. Of course from a single satellite, it will be symmetrical in both naarth and south , but get the Yindoos to vouch that it didnt fly over their territory and you have a pretty good estimate of where it landed after X hours in the air.

anishns · Post by **anishns** » 25 Mar 2014 09:27

One possible explanation.....on the doppler theory. Anyone kind enough to translate in layman terms to non-engg folks?

http://www.pprune.org/rumours-news/5355 ... ost8399298

Theo_Fidel · Post by **Theo_Fidel** » 25 Mar 2014 09:27

Vina,

INMARSAT webpage says that this is no ordinary passive ping. It is initiated by ground sent to satellite. Satellite queries plane and plane responds. Possibly the difference between query and response is part of what the 'doppler' comment was all about. As they said they compared it to signals planes send during normal flight to Beijing.

http://rg.to/file/b867c0d0472bb30cb700d ... m.rar.html

vina · Post by **vina** » 25 Mar 2014 10:10

The Malaysians are B*stards. They have blood on their hands. The Inmarsat analysis was done on Mar 9th, the day after the crash on 8th Mar. The Americans and Brits did baboo giri and the Malaysians got their hands on the Inmarsat analysis on 12th Mar . The Malaysians sat on it for a further 3 days , and released the info and that too only partially.

They took the last known position of the plane, the last known ping from the plane , ignored the Inmarsat triangulated path and published a nonsensical arc going north and south.

Washington Post says this.

During those critical days after the flight went missing -- when debris from any crash might have been sinking or simply drifting far away, when survivors could have clinging to life aboard rafts--multiple countries were sending ships to scour the waters in the Gulf of Thailand and then later in the South China Sea, all areas far from where Inmarsat's data was pointing. Two days after Inmarsat's experts had already done the math, searchers were still inspecting debris off the coast of Vietnam.

On Tuesday, March 18, three days after the map (the mangled one by the Malaysians) above was released, Australia announced that together with the U.S. National Transportation Safety Board, it had narrowed down the search area to just three percent of the southern corridor. The Americans and Australians took the Inmarsat triangulations – in other words, data from each of those hourly pings -- along with some assumptions about the plane's speed, and out came a much smaller search area, shown below

Adm Arun Prakash was right. The Malaysians were dicks and all countries were wasting resources on a massive scale, and searched for close to 8 days in totally wrong places. The Chinese better be hopping mad with the Malaysians. I wonder why they did what they did.

WTF!

svinayak · Post by **svinayak** » 25 Mar 2014 10:19

China, which has been at the forefront of the global search for the missing Malaysia Airlines flight MH370, now finds its strength limited as the crisis enters its third week, the New York Times reported today.

"The painful process of working with Malaysia in searching for the airplane and investigating what went wrong in the early hours of March 8 has revealed the limits of China’s power, influence and technological and military might in the region, despite its rapid rise as a rival to the United States and American strategic dominance of the Western Pacific," said the paper.

http://www.themalaysianinsider.com/mala ... -says-repo

ldev · Post by **ldev** » 25 Mar 2014 10:39

anishns wrote:One possible explanation.....on the doppler theory. Anyone kind enough to translate in layman terms to non-engg folks?

http://www.pprune.org/rumours-news/5355 ... ost8399298

As far as I can understand it (caveat I am no engineer), the Inmarsat satellite transmits its query at a certain frequency, the relative movement of the satellite and the plane causes the return from the plane (the ping) to come in at a slightly modified frequency due to the doppler effect. What is also interesting from that discussion is that geo stationary satellites are not strictly stationary because of the relative motion of the sun and the gravitational pull of the moon. They have a slight wobble which becomes more pronounced as a geo satellite stays longer in orbit, less fuel and efforts to conserve remaining fuel hence fewer corrections to wobble. This particular satellite has been in orbit for some time, an older generation of INMARSAT satellites. Apparently it has a North to South and South to North wobble every 11 hours i.e. it crosses the equator N-S-N every 11 hours by as much as 1.69 degrees. That supposedly is what also helped the Inmarsat engineers calculate the plane's heading i.e. if the satellite changed from a NS to a SN motion or vice versa e.g. during the 7 odd hours of the plane's journey, it would then have allowed the Inmarsat techies to establish with greater certainty whether the plane was on a northerly or a southerly heading by the doppler shift in the received frequency.

shanth · Post by **shanth** » 25 Mar 2014 11:00

anishns wrote:One possible explanation.....on the doppler theory. Anyone kind enough to translate in layman terms to non-engg folks?

http://www.pprune.org/rumours-news/5355 ... ost8399298

Let me give it a try:

* Doppler is the fancy name given to frequency translation. So when a train approaches you, you can hear the sound of the whistle changing. The amount of change depends on how fast the train approaches.
* The change also depends on the angle at which the train approaches you. So if the train approaches you directly (angle ==0) you will experience the full change in sound. If the train is moving in a circle around you, never towards you, you will not hear any change in sound, no matter how fast the train moves.
* Also assume that +ve numbers in the graph means the plane is approaching the satellite and -ve numbers means the plane is moving away from satellite.
* With the above in mind, lets look at the statement "At the start of its silent flight, MH370 was flying at a speed of 219.3 kph (kilometers per hour) directly towards the satellite and 821 kph directly perpendicular to the line-of-sight."
* Assumption is that the plane is flying at 850 km/h over the air. but not directly at the satellite.
* Let alpha be the angle between satellite and plane. If alpha = 0, plane is approaching satellite directly and the satellite will see a speed of 850 Km/h.
* That is the plane is approaching at an angle alpha towards the satellite such that speed_of_plane*cos(alpha) = 219.3 and speed_of_plane*sin(alpha) = 821.
* Now "Therafter, the airplane flew in a direction further and further away from the satellite, and the component of the velocity along the line-of-sight decreased."
* Maybe the person dint use the best word when he typed "line-of-sight decreased" ....I think the graphs show that the angle between the plane and satellite is decreasing, and the plane is moving away from the satellite. That is the line of sight is increasing and the plane is moving away. Thus +200 becomes -600.
* So now a good way is to ask the question:
* Given the starting location, and the doppler shifts so given, where should the plane go to match this data.
* This is what they analyzed in the last few days given other flights.

* "I will say this: the Inmarsat people must be very good engineers to detect such small changes in a 1600MHz carrier"
* 200Hz for satellite communication such as Inmarsat is a big deal. Most of the systems are designed for much lower error.

* Most-likely the data pings are sent as a "RACH" type packet.(RACH is a standard term also used in some sat comm)
* It is very likely that the RACH modem information such as SNR, time-offset and freq-offset are stored in logs.

-Shanth

habal · Post by **habal** » 25 Mar 2014 12:43

Maybe the need is to have more satellites patrolling the empty quarter. aka the Southern Indian Ocean.