Malaysia Airlines Flight Goes Missing En Route to China - Flight MH370

[anterian]

Latency? Signal strength? Signal travel time?
Some or all of them an probably some more combined with known planes on known locations with known ping values. All correlated and compared to eachother. I can imagine this takes huge data processing power, hence time.

They used very precise Doppler analysis and compared it with previous data from known sources. Basically the increased or decreased Doppler shift to the receiver tells if the signal source is moving towards or away from the receiver, increased if approaching, decreased if moving away.
you can work it out yourself here : http://www.calctool.org/CALC/phys/default/doppler

[voyager10]

MH370 - BIG PHOTOS :


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[voyager10]

Satellite 'pings' revealed missing Malaysia plane's path

LONDON: The satellite operator Inmarsat said Monday it managed to work out which direction the missing Malaysia Airlines plane flew in by measuring the Doppler effect of hourly 'pings' from the aircraft.

Malaysia's prime minister announced earlier that the Inmarsat analysis of flight MH370's path placed its last position in remote waters off Australia's west coast, meaning it can only have run out of fuel above the southern Indian Ocean.

Inmarsat explained how they plotted models of the flight's route by measuring the Doppler effect of satellite pings, giving corridors arcing north and south along which the plane could have flown for at least five hours.

Despite the plane's communication systems being switched off, satellite pings were still bouncing back from the aircraft, which vanished on March 8 with 239 people on board while flying from Kuala Lumpur to Beijing.

The pings are sent from a ground station to a satellite, then onto the plane, which automatically sends a ping back to the satellite and down to the ground station.

They do not include global positioning system (GPS) data, time or distance information.

So the British satellite operator measured the amount of time it took for the pings to be returned.

"We looked at the Doppler effect, which is the change in frequency due to the movement of a satellite in its orbit," Chris McLaughlin, Inmarsat's senior vice president of external affairs, told Britain's Sky News television.

"What that then gave us was a predicted path for the northerly route and a predicted path the southerly route."

"We don't know whether the plane stayed at a constant speed; we don't know whether its headings changed subsequently," he explained.

Therefore, "we applied the autopilot speeds -- about 350 knots. We applied what we knew about the fuel and range of the aircraft to hit the series of ping information we had.

"Normally you'd want to triangulate, often you'd have GPS. But because aircraft in that region are not mandated to send out signals of their location we were working from blind, so this is very much a unique approach -- the first time it's been done."

Ran out of fuel

They then compared those figures to data from other Malaysia Airlines planes and similar flight routes, which definitively showed the plane could only have been going down the southern corridor, and would eventually have run out of fuel.

They established an "extraordinary matching" between Inmarsat's predicted southern path and readings from other planes on such routes.

The BBC reported that as far as could be worked out, the plane was flying at a cruising height, above 30,000 feet (9,100 metres). They found no evidence of fluctuating heights.

Inmarsat handed over new information to Britain's Air Accidents Investigation Branch on Sunday for checking.

"By yesterday they were able to definitively say that the plane had undoubtedly taken the southern route," said McLaughlin.

He called for all commercial aircraft to be fitted with existing technology that would mean a plane cannot go missing.


Source : http://english.astroawani.com/news/s...-path-32490?cp

[voyager10]

The MH370 crash timeline

KUALA LUMPUR: Malaysia announced Monday that a Malaysia Airlines plane which went missing more than two weeks ago crashed in the Indian Ocean, bringing a measure of closure to relatives of the 239 people on board.

Here is a timeline of major developments in the hunt for flight MH370:

SATURDAY MARCH 8

- The Boeing 777 takes off from Kuala Lumpur at 12:41 am, bound for Beijing. It vanishes from Malaysian civilian radar at 1:30 am, just before passing to Vietnamese air traffic control. It blips on military radars until 2:15 am, but that sighting is only later identified as flight MH370.

- Vietnam launches a search operation that expands in the following days into a multinational hunt in the South China Sea.
- Vietnamese planes spot two large oil slicks near the plane's last known location, but they turn out to be a false alarm.

- It emerges that two passengers were travelling on stolen EU passports, fuelling speculation of a terrorist attack. The two Iranian men are later revealed as suspected illegal immigrants.

SUNDAY MARCH 9

- Malaysia's air force chief says the plane may have turned back towards Kuala Lumpur for no apparent reason, citing radar data.

- A Vietnamese plane spots possible debris off southwest Vietnam - another false alarm.

MONDAY MARCH 10

- Malaysia sends ships to investigate a sighting of a possible life raft, but only flotsam is found.

TUESDAY MARCH 11

- The search area now includes land on the Malaysian peninsula, the waters off its west coast, and an area to the north of Indonesia's Sumatra island - all far from the flight's scheduled route.

WEDNESDAY MARCH 12

- Malaysia expands the search zone again to include the Malacca Strait off its west coast and the Andaman Sea north of Indonesia.

- Malaysia's air force chief says an unidentified object was detected on military radar north of the Malacca Strait early Saturday, but says it is still being investigated.

THURSDAY MARCH 13

- Chinese satellite images of suspected debris in the South China Sea are found to be yet another false lead.

FRIDAY MARCH 14

- The hunt spreads to the Indian Ocean after the White House cites "new information" that the jet may have flown on after losing contact.

SATURDAY MARCH 15

- At a dramatic news conference, Malaysian Prime Minister Najib Razak announces that the plane appears to have been flown deliberately for hours, veering sharply off-route at roughly the same time that its communications system and transponder were manually switched off.

- Satellite data now places the jet anywhere in one of two huge corridors of land and sea

- a northern one stretching into Central Asia and a southern one swooping deep into the Indian Ocean. The search in the South China Sea is called off.

SUNDAY MARCH 16

- As the number of countries involved in the search jumps to 26, experts examine a flight simulator installed in the home of Captain Zaharie Ahmad Shah.

MONDAY MARCH 17

- After conflicting statements, officials confirm that the relaxed-sounding last words from the cockpit - "All right, good night" - came two minutes before the plane's transponder was shut down.

- Malaysia Airlines says the voice is believed to be that of co-pilot Fariq Abdul Hamid. Police probe a potential political motive on the part of Captain Zaharie, a supporter and distant relative of Malaysian opposition leader Datuk Seri Anwar Ibrahim.

TUESDAY MARCH 18

- Australian and US surveillance planes begin combing 600,000 square kilometres (230,000 square miles) of the remote Indian Ocean in the southern search corridor.

- Desperate relatives of the Chinese passengers threaten to go on hunger strike.

WEDNESDAY MARCH 19

- Malaysia says background checks on almost all passengers and crew have produced no "information of significance".

- Angry Chinese relatives try to gatecrash Malaysia's daily media briefing on the investigation, unfurling a banner reading: "Give us back our families."

- With the 26-country search apparently bogged down in coordination problems, Thailand's air force reveals its military radar had picked up what appeared to be flight MH370 just minutes after it was diverted.

THURSDAY MARCH 20

- Australia says satellites have spotted two objects, one estimated at 24 metres (79 feet) long, in a remote area of the southern Indian Ocean.

- Four surveillance aircraft are dispatched to the area, as is a Norwegian merchant ship. But in poor weather, they spot nothing.

FRIDAY MARCH 21

- Planes spend a second fruitless day searching the remote stretch of the Indian Ocean.

- Malaysia asks the United States to provide undersea surveillance technology.

SATURDAY MARCH 22

- China releases a new satellite photo of an object floating 120 kilometres (75 miles) from those pictured in the Australian images.

SUNDAY MARCH 23

- Along with French satellite data indicating floating objects in the area, sightings of a wooden pallet and other debris raise hopes of a breakthrough.

MONDAY MARCH 24

- China and Australia both announce fresh, separate sightings of objects in the sea, adding to the mounting evidence of debris in the Indian Ocean.

- The US Navy orders a specialised black box locator sent to the area.

- Late in the evening, Malaysian Prime Minister Datuk Seri Najib Tun Razak announces "with deep sadness and regret" that MH370 crashed into the Indian Ocean, citing new analysis of satellite data. In a message to families, the airline states "we have to assume" the plane was lost at sea. - AFP


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[airnrail]

You might want to ease back on the gas with that a tad (apply the speedbrakes). The fat lady hasnt sung.

Just say it can be confirmed that the plane is in the Indian Ocean around the present search area. It is in international waters, therefore the investigation belongs to the nation that owns the plane. It only becomes another nation's responsibility if the aircraft crashes within that nation's territory. Malaysia has declared all souls lost, therefore recovery of as much of the plane as possible together with the flight recorders now becomes the sole objective and it is Malaysia's responsibility.

We know from the Air France experience that recovery can take a long time but first you have to find the plane and that is shaping up as being an exceedingly difficult task. The present search will continue for a little while longer but if nothing conclusive is found quickly, all those planes and ships are just not going to stay out there. Malaysia will keep going - it has to - and the US will maintain some involvement to protect Boeing's interests, China will keep looking hoping to stick it to Malaysia. Everybody else will want a fee for service from Malaysia if they are to stay in the search. I emphasize the point that the search is no longer for people and that's when the humanitarian aid cuts out. Sure, Australia for instance, would still make the Pearce Base available and probably one naval vessel at sea but I can't see the government paying the tab to keep multiple Orions and chartered biz jets in the air every day for an extended period looking for a plane wreck that is not our responsibility. I also don't think the view of other governments would be much different. I guess it comes down to how deep are Malaysia's pockets.

It would be wonderful if something conclusive would happen quickly while all the resources are in place. If not I stand by my contention that this whole matter will quickly slip away and almost nobody will be talking about it very soon.

Then one day something will wash up somewhere or a lookout on a ship will spot something.

BTW Gregg, welcome back. Haven't seen you about on here for weeks. State of Origin soon mate - then we might talk about something other than planes! Cheers. John

[Mike]

Please stop posting conspiracy theories and links to stupid "DAHBOO77" YouTube videos. If you have any conspiracy theories please find another forum to post your bullshit. This thread is from now and on ONLY available for posting facts about the crash of MH370 in South Indian Sea and about the ongoing search operation.

[POR911]

Thanks Mike, FR24 has always been an informative, and caring site. Many people have been lost. As you say, Known facts only.

[Oblivian]

Just been made aware of another BizJet enroute to Perth to assist with the search. Along with a number of australian based Global hoppers. It would appear their range is useful in SAR ops.

ZK-KFB, Gulfstream G650. Charterd around NZ under operation of Execujet NZ (Operated on behalf of owner director Peter Jackson - rego reflects his wife and childrens names)

http://www.mrcaviation.blogspot.co.nz/2014/03/lost-updated.html

There is a Perth Spotters blog up with the play of the comming and going

http://aegwaspotters.blogspot.co.nz/

/edit 1040 UTC - SOME mlat testing taking place in the Perth region (refer MLAT thread - pending arrival of another receiver) which MAY be made public and assist in identifying aircraft involved in the search.

However once again, it must be stipulated - the search site is 2300kms from land This is about 2000kms short of the average receiver range. Let alone the private jet and military presence which do not have full ADSB location revealed. Therefore only those laying a track toward the middle of the ocean can be seen on arrival/departure

[cretanrunner]

Mike, I can't believe you have been so patient. If it were me I would have blocked certain posters many, many pages back.

[speedbird1960]

Latest update from Aviation Herald.

"On Mar 25th 2014 Malaysia's Transport Minister reported in the daily press conference the last complete handshake between satellite and aircraft took place at 00:11Z as previously reported, there is evidence that another incomplete hand shake occurred at 00:19Z. A new method based on Doppler effect to compute the speed of the aircraft relative to the satellite and compare these results with other aircraft along the northern and southern corridor showed little match within the northern corridor but good match with the southern corridor, the method permitted to roughly locate the aircraft at the time of the last complete handshake. As result the search in the north corridor as well as in the northern part of the southern corridor have been aborted, the search area has been narrowed to 469,407 square nautical miles instead of the previous 2.24 million square nautical miles. Works to further narrow down the search area including decoding and analysis of the last incomplete handshake at 00:19Z continue. In the search area near Perth six Chinese ships are estimated to arrive on Mar 26th, HMAS Success is going to return to the search area after temporarily having left the area due to rough sea and weather. The Transport minister said quote: "In recent days Inmarsat developed a second innovative technique which considers the velocity of the aircraft relative to the satellite. Depending on this relative movement, the frequency received and transmitted will differ from its normal value, in much the same way that the sound of a passing car changes as it approaches and passes by. This is called the Doppler effect. The Inmarsat technique analyses the difference between the frequency that the ground station expects to receive and one that is actually measured. This difference is the result of the Doppler effect and is known as the Burst Frequency Offset. The Burst Frequency Offset changes depending on the location of the aircraft on an arc of possible positions, its direction of travel, and its speed. In order to establish confidence in its theory, Inmarsat checked its predictions using information obtained from six other B777 aircraft flying on the same day in various directions. There was good agreement. While on the ground at Kuala Lumpur airport, and during the early stage of the flight, MH370 transmitted several messages. At this stage the location of the aircraft and the satellite were known, so it was possible to calculate system characteristics for the aircraft, satellite, and ground station. During the flight the ground station logged the transmitted and received pulse frequencies at each handshake. Knowing the system characteristics and position of the satellite it was possible, considering aircraft performance, to determine where on each arc the calculated burst frequency offset fit best. The analysis showed poor correlation with the Northern corridor, but good correlation with the Southern corridor, and depending on the ground speed of the aircraft it was then possible to estimate positions at 0011 UTC, at which the last complete handshake took place. I must emphasise that this is not the final position of the aircraft. There is evidence of a partial handshake between the aircraft and ground station at 0019 UTC. At this time this transmission is not understood and is subject to further ongoing work. No response was received from the aircraft at 0115 UTC, when the ground earth station sent the next log on / log off message. This indicates that the aircraft was no longer logged on to the network. Therefore, sometime between 0011 UTC and 0115 UTC the aircraft was no longer able to communicate with the ground station. This is consistent with the maximum endurance of the aircraft. This analysis by Inmarsat forms the basis for further study to attempt to determine the final position of the aircraft. Accordingly, the Malaysian investigation has set up an international working group, comprising agencies with expertise in satellite communications and aircraft performance, to take this work forward." The Minister handed out documents prepared by Inmarsat and the AAIB, see below.

In the evening of Mar 25th 2014 AMSA announced that the search is going to resume on Wednesday (Mar 26th) after gale force winds subsided and visibility improved. 12 aircraft and 5 ships (HMAS Success and 4 chinese ships) are expected in the search area on Wednesday."

http://avherald.com/h?article=4710c69b&opt=0

[POR911]

Speedbird, your rendition and that of the AVherald provided an excellent time line...It is no wonder the Malaysian Gov't were struggling to oversee this information 'overload'. The constant badgering by journalists must have been terrible for them.

[smay69]

They used very precise Doppler analysis and compared it with previous data from known sources. Basically the increased or decreased Doppler shift to the receiver tells if the signal source is moving towards or away from the receiver, increased if approaching, decreased if moving away.
you can work it out yourself here : http://www.calctool.org/CALC/phys/default/doppler

Its interesting, apparently they did not measure a doppler shift at the receiver of whether the source was moving toward or away (I suspected this would not be archived data) - they used the doppler shift based on the satellite moving in its orbit (which I imagine is very important data to keep!) and using the successive pings to determine if it was the northern or southern arc. And they seem to conclusively have determined it was the southern arc (also based on data of comparable aircraft with know position, heading, and speeds during their pings). That is all. The fact they believe it lies where they think it does in the southern ocean is purely based on estimated average speed and a straight line heading, and the time they received the last ping (in addition to what they believe the fuel would allow).

[avox]

INMARSAT and the northern arc

Its interesting, apparently they did not measure a doppler shift at the receiver of whether the source was moving toward or away (I suspected this would not be archived data) - they used the doppler shift based on the satellite moving in its orbit (which I imagine is very important data to keep!) and using the successive pings to determine if it was the northern or southern arc. And they seem to conclusively have determined it was the southern arc (also based on data of comparable aircraft with know position, heading, and speeds during their pings). That is all. The fact they believe it lies where they think it does in the southern ocean is purely based on estimated average speed and a straight line heading, and the time they received the last ping (in addition to what they believe the fuel would allow).

a) INMARSAT is in geostationary orbit, so its speed relative to surface is zero.
b) Doppler shift indicates relative speed between source and receiver. Since INMARSAT satellite is above equator, this data cannot tell northern and southern arc apart - it's symmetrical.
c) Apparently the northern route was eliminated solely because that route crossed Indian, Pakistani and other military radars and all nations declared that they didn't see the aircraft.

If anyone knows a scientific method that can determine position north or south of the equator just by looking at Doppler shift and round-trip handshake times from a geostationary satellite, please do explain.

[smay69]

a) INMARSAT is in geostationary orbit, so its speed relative to surface is zero.
b) Doppler shift indicates relative speed between source and receiver. Since INMARSAT satellite is above equator, this data cannot tell northern and southern arc apart - it's symmetrical.
c) Apparently the northern route was eliminated solely because that route crossed Indian, Pakistani and other military radars and all nations declared that they didn't see the aircraft.

If anyone knows a scientific method that can determine position north or south of the equator just by looking at Doppler shift and round-trip handshake times from a geostationary satellite, please do explain.

I was just reading their (inmarsat's) own explanation a few posts up. It does seem strange that something in geostationary orbit would be moving its its orbit - although it is likely a control system keeping it there which means minor oscillations around the geostationary point. It sounds like even though what you state it true, there was some difference in ping signatures that they could match up with real world data from other aircraft based on instaneous satellite motions during pings. If everything were completely symmetrical and the satellite always compeletly stationary WRT the surface, there would still be no way to tell northern or southern arc...

[F-EGLF1]

a) INMARSAT is in geostationary orbit, so its speed relative to surface is zero.

If anyone knows a scientific method that can determine position north or south of the equator just by looking at Doppler shift and round-trip handshake times from a geostationary satellite, please do explain.

Although the salellite is geostationary it is far from fixed, Inmarsat have stated that it moves in a figure-8 pattern, by comparing the doppler shifts from other 777 aircraft in the air AT THE SAME TIME they could calculate the satellite shift over the flight period, this allowed them to infer the position of the plane from the doppler shift caused by the satellite movement. the AviationHerald web site has further details.