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giới thiệu quý vị website : http://www.flightradar24.com/ .website
này giúp theo dõi mọi chuyến bay trên hành tình này ... khắp năm châu ... Dùng
trong trường hợp có đi đón ai hoặc muốn biết người thân mình đi nơi xa có bị
trễ máy bay hoặc gặp trở ngại . Cứ search (bên góc trái) hoặc click vào
một chiếc máy bay trên đường bay, chúng ta sẽ biết hãng máy bay, số máy bay .. đầy đủ
chi tiết ... Hãy thử coi. Đây là một chuyến đang bay về phi trường Chicago.
How
it works
Flightradar24
is a flight tracker that shows live air traffic from around the world.
Flightradar24 combines data from several data sources including ADS-B, MLAT and
FAA. The ADS-B, MLAT and FAA data is aggregated together with schedule and
flight status data from airlines and airports to create a unique flight
tracking experience on www.flightradar24.com and in Flightradar24
apps.
ADS-B
The
primary technology that we use to receive flight information is called
automatic dependent surveillance-broadcast (ADS-B). The ADS-B technology itself
is best explained by the image to the right.
Aircraft
gets its location from a GPS navigation source (satellite)
The
ADS-B transponder on aircraft transmits signal containing the location (and
much more)
ADS-B
signal is picked up by a receiver connected to Flightradar24
Receiver
feeds data to Flightradar24
Data
is shown on www.flightradar24.com and in Flightradar24 apps
Today,
roughly 60% of all passenger aircraft (70% in Europe, 30% in the US
Flightradar24
has a network of about 2000 ADS-B receivers around the world that receives
plane and flight information from aircraft with ADS-B transponders and sends
this information to our servers. Due to the high frequency used (1090 MHz) the
coverage from each receiver is limited to about 250-400 km (150-250 miles) in
all directions depending on location. The farther away from the receiver an
aircraft is flying, the higher it must fly to be covered by the receiver. The
distance limit makes it very hard to get ADS-B coverage over oceans.
About
98% of Europe is covered with ADS-B receivers.
There is also good ADS-B coverage in USA ,
Canada , Caribbean, Brazil , Russia ,
Middle East , India ,
Japan , Thailand , Malaysia
and Australia
MLAT
In
some regions with coverage from several FR24-receivers we also
calculate positions of aircraft with the help of Multilateration (MLAT),
by using a method known as Time Difference of Arrival (TDOA). By measuring the
difference in time to receive the signal from aircraft with an older
ModeS-transponder, it's possible to calculate the position of these aircraft.
Four FR24-receivers or more, receiving signals from the same aircraft, are
needed to make MLAT work. That means that MLAT coverage can only be achieved
above about 10000-20000 feet as the probability that signal can be received by
four or more receivers increases with increased altitude.
MLAT
coverage is today limited to some parts of Europe and North
America , but expanding fast.
FAA
In
addition to ADS-B and MLAT data, we also get data from the Federal Aviation
Administration (FAA) in the United States
FAA
data is based on radar data (i.e. not just planes with ADS-B transponders) and
includes most scheduled and commercial air traffic in US and Canadian air space
+ parts of Atlantic and Pacific Ocean .
Aircraft
visible on Flightradar24 (within ADS-B coverage)
Common
aircraft models that usually have an ADS-B transponder and are visible on
Flightradar24 (within ADS-B coverage):
All
Airbus models (A300, A310, A318, A319, A320, A321, A330, A340, A350, A380)
Antonov
AN-148 and AN-158
ATR
72-600 (most new deliveries)
BAe
ATP
BAe
Avro RJ70, RJ85, RJ100
Boeing
737, 747, 757, 767, 777, 787
Bombardier
CS100 and CS300
Embraer
E190 (most new deliveries)
Fokker
70 and 100
McDonnell
Douglas MD-10, MD-11
Sukhoi
SuperJet 100
Some
newer Ilyushin and Tupolev (for example Il-96 and TU-204)
Common
aircraft models that usually do not have an ADS-B transponder and are not
visible on Flightradar24 (within ADS-B coverage):
"Air
Force One"
Antonov
AN-124 and AN-225
ATR
42, 72 (except most new deliveries of ATR 72-600)
Boeing
707, 717, 727, 737-200, 747-100, 747-200, 747SP
BAe
Jetstream 31 and 32
All
Bombardier CRJ models
All
Bombardier Dash models
All
CASA models
All
Dornier models
All
Embraer models (except most new deliveries of Embraer E190)
De
Havilland Canada
Fokker
50
McDonnell
Douglas DC-9, MD-8x, MD-90
Saab
340 and 2000
Most
helicopters
Most
older aircraft
Most
business jets
Most
military aircraft
Most
propeller aircraft
Of
course there are lots of exceptions from these rules. There are some older
A300, A310, A320, B737, B747, B757, B767, MD10, MD11 aircraft flying without an
ADS-B transponder, which make those aircraft invisible on Flightradar24 when in
areas with ADS-B coverage only. But there are also some Twin Otters, Saab 340,
Saab 2000 and MD-80 aircraft with an ADS-B transponder that are visible on
Flightradar24.
Aircraft
visible on Flightradar24 (within MLAT or FAA coverage)
In
regions with MLAT or FAA coverage most of the air traffic is visible
independent of aircraft type. But as mentioned above MLAT coverage is limited
to some areas with many FR24-receivers and can normally only be achieved on
altitudes above about 10000-20000 feet. Data provided by FAA is often missing
aircraft registration information.
Blocking
For
security and privacy reasons information about some aircraft is limited or
blocked.
Coverage
map
In
areas where Flightradar24 normally have coverage, all major airports are marked
with blue airport markers.
Flightradar24
relies on volunteers around the world for the majority of our coverage. Find
out how you can contribute and host a receiver.
Please
note that coverage and aircraft visibility is dependent of many parameters
including aircraft type, aircraft transponder type, aircraft altitude and
terrain so coverage is different for different aircraft. If an aircraft you are
looking for is not visible on Flightradar24 it either does not have correct
transponder or it's out of Flightradar24 coverage.
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