Questions tagged [ads-b]

ADS-B (Automatic Dependent Surveillance - Broadcast) is a surveillance technology that works by broadcasting GNSS position, velocity and identity to interested parties. It can be used as a supplement to or alternative to radar systems for tracking aircraft. It is a component of the FAA's NextGen ATC improvements, as well as the European SESAR programme.

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Why don't all commercial aircraft transmit GPS data in real time?

It seems strange that trucks and taxis can be set up to transmit GPS data in real time but aircraft cannot. Wouldn't this be a useful function and feasible to implement?
JoelFan's user avatar
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32 votes
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Why are commercial flights not (publicly) trackable in some locations?

Flying BA15 from London to Sydney, I noticed that the flight is not tracked over Turkmenistan and Afghanistan, except for a short ping. Is this for security reasons? Do planes disable their ADS-B, or ...
Mantriur's user avatar
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31 votes
4 answers
13k views

Why do aircraft on FlightRadar24 jump around randomly sometimes?

I use FlightRadar24 on my iPad to track friends'/family's flights when they are traveling (not paranoia, just curious). I've noticed that, quite often, their plane will jump from one location to ...
Jae Carr's user avatar
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27 votes
2 answers
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What are these vehicles with no callsign used for?

I keep seeing these land based vehicles whenever I am looking airports on flightradar24, like in the image below: Why do they come up on the radar? Do they have a transponder? What is the purpose of ...
hat's user avatar
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24 votes
3 answers
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What is ADS-B and who needs it?

I read that ADS-B is required by the year 2020. What does this mean? What is ADS-B used for, and who needs it?
xpda's user avatar
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22 votes
4 answers
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My N number showed up on another plane's flight on FlightRadar24. How does that happen?

My Cessna 150F has never had ADS-B out. It has had the same N number since 1967. But yet, FlightRadar24 shows a flight a few weeks ago, perfectly tracing the coast north of San Diego, 2,000 miles from ...
David Hempy's user avatar
22 votes
1 answer
7k views

How does ATC radar/ADS-B ground stations not get confused with signals sent from multiple aircraft?

I understand that the radar sends a 1030 MHz interrogation signal to an aircraft and the aircraft's transpoder responds using 1090 MHz. When it comes to Mode S squitter, the transmissions are ...
Clive's user avatar
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17 votes
2 answers
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Why are Search & Rescue aircraft looking for the OceanGate Titan submarine not visible on ADS-B Exchange?

Currently, there is an ongoing Search and Rescue mission being conducted by Canada, the United States, and commercial operators to find and rescue the crew of the OceanGate Titan submersible vessel (...
End Anti-Semitic Hate's user avatar
17 votes
4 answers
6k views

Why are transponders to be turned off when in formation?

Reading through FAR AIM. I came across the ADSB section which stated that transponders should be turned off except for the lead plane. Why is this?
Boeing787's user avatar
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16 votes
6 answers
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How can ADS-B replace primary radar when FlightRadar24, using ADS-B, is so inaccurate?

I read the following on Flightradar24.com's 'How it works' page. The percentage of aircraft equipped with ADS-B receivers is steadily increasing though, as they will become mandatory for most ...
Sanchises's user avatar
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Why are there so many ADS-B ground towers in western Colorado?

I was reading up on Appaero's new ADS-B OUT transponder and clicked over to the Stratus coverage page for some reason. Then I glanced at the map, and noticed something interesting: Western Colorado ...
egid's user avatar
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15 votes
3 answers
4k views

Do pilots ever use the aircraft's ICAO 24-bit address when communicating with ATC?

Do pilots know the unique ICAO 24-bit hexadecimal code for their aircraft? Do they ever give it directly to ATC? For example, to controllers who make the flight strips with destination, departure, ...
gary's user avatar
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14 votes
1 answer
3k views

Will a portable ADS-B unit, like Stratus, meet the requirements for my aircraft to be ADS-B equipped by the 2020 mandate?

There is a lot of confusion around what it means to have ADS-B. What is the minimum equipment required to meet the mandate? Can I use a Stratus to meet that requirement?
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13 votes
1 answer
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What is the relation between aircraft altitude and ADS-B coverage?

While reading the description of ADS-B given on the FR24 website (ADS-B How it works), I came across this sentence: The farther away from the receiver an aircraft is flying, the higher it must fly ...
hat's user avatar
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12 votes
1 answer
2k views

Why did this aircraft re-route?

I was looking through my ADSB Virtual Radar outputs couple days ago and saw a weird re-route for one of the aircraft that looked out of place. Can one of the pilots/ATC guys pitch in to help me ...
KORD4me's user avatar
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12 votes
1 answer
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How does the ADS-B compact position report NL() function work?

I'm trying to decode ADS-B messages for a school project, and I cannot reproduce the results of the NL() function as described in this document. I've seen the same formula in several other documents. ...
Kevin's user avatar
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11 votes
5 answers
3k views

How can ADS-B be secure when it is based on self-reporting?

By all reports, ADS-B is the future of air navigation and ATC. In the simplest definition, ADS-B is aircraft self-reporting GPS position to benefit everyone. How is this secure? Seems like someone ...
digitgopher's user avatar
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10 votes
2 answers
4k views

Is ADS-B intended to replace other traffic management systems?

What is the main purpose of ADS-B? How do aircrafts interact with each other using them? Is it intended to replace the Traffic Collision Avoidance System (TCAS) or ground based Air Traffic Control (...
Davide's user avatar
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10 votes
2 answers
1k views

Why does ADS-B altitude from multiple landed planes vary so much from one plane to another?

When viewing ADS-B data from sites like FlightAware and Flightradar24 (and also from a personal antenna), the landed altitudes vary greatly from one aircraft to another. What accounts for this ...
bhamjman's user avatar
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10 votes
2 answers
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What is the difference between ADS-B UAT and ADS-B ES?

Why would an owner decide to put in an ADS-B UAT transceiver versus an ADS-B ES transceiver? What are the advantages and disadvantages of both systems?
wbeard52's user avatar
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10 votes
2 answers
502 views

What will create a "traffic puck" on the UAT band?

I know that for ADS-B in the US to receive TIS-B information you need to be a participating aircraft (ie ADSB-Out). My question is more specifically, if you are flying an aircraft with a 1090ES ...
Kevin Jablonski's user avatar
9 votes
1 answer
2k views

Does ADS-B use its own antenna?

In the aircraft we have: ADS-B out/in using 1090ES A/C or Mode S transponder for SSR grounding interrogation. Does the ADS-B out use the same antenna as Mode S or does it use its own antenna?
Oussama SDR's user avatar
9 votes
2 answers
335 views

Received ADS-B TC=31 message with non-existent version 3?

On several dates, my ground station received some airborne operational status ADS-B messages (TC=31) where the version number was reported as 3. As far as I know, ...
John Wiseman's user avatar
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9 votes
1 answer
5k views

Are squawk codes used with ADS-B?

When using ADS-B are squawk codes still necessary or does the unit provide a discrete code (like a tail number or something) that is recognized by ATC?
TomMcW's user avatar
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8 votes
2 answers
938 views

Will 1090 Mhz band become too congested in the future?

1090 Mhz is currently used for SSR Mode A/C replies and Mode S communication(ELS-EHS replies and ADS-B broadcasts) by civilian aircraft and some of military IFF modes. With the infamous 2020 ADS-B ...
Mehmet Çağrı Köse's user avatar
8 votes
1 answer
428 views

Will ICAO 24 bit addresses suffer the same fate of IPv4?

As we know; both IP addresses and Mode S (ICAO) addresses are relatively short. With local networks and NAT (Network Address Translation), there is not an urgent need for transition to IPv6. But how ...
Mehmet Çağrı Köse's user avatar
8 votes
2 answers
5k views

How can I get flight destination from ADS-B?

If I have aircraft details such as the callsign, transponder code, and ads-b info, how can I look up the departure and arrival airdrome? Is there an API to obtain this information in a programmatic ...
Peter M.'s user avatar
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8 votes
1 answer
3k views

How do military fighter aircraft identify themselves and each other?

I live in an area where there is much NATO military activity. Often there are various fighter aircraft fly-overs. But none of the common websites such as flightradar24, flightaware and ...
not2qubit's user avatar
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7 votes
2 answers
3k views

Does baro altitude from ADSB represent height above ground level or height above mean sea level?

I am retrieving ADSB data from Opensky-network.org. I would like to know what the baro altitude represents, is it the height above ground level or above mean sea level ?
Canis_Lupas's user avatar
7 votes
2 answers
11k views

What's the relation between ADS-B and MODE S

I know that ADS-B uses 1090ES or UAT to transmit their signal, and 1090 ES is related to MODE S. Here's my questions. What's the 1090 ES? If a aircraft uses 1090 ES as their ADS-B out, Does aircraft ...
Min's user avatar
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7 votes
1 answer
2k views

What is the broadcast rate of an ADS-B message?

From what I know, ADS-B (DF=17) message structure is 112 bits long. In terms of type of messages it transmits, there are aircraft identification, surface position, airborne position with baro altitude ...
Agha's user avatar
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7 votes
1 answer
640 views

Question about congestion of the 1090MHz frequency

I'm no expert so there's likely to be a lot of mistakes in this post. ADS-B - Automatic Dependent Surveillance - Broadcast, (out) transmits (in) receives position data from/to other aircraft and to ...
Rory McDonald's user avatar
7 votes
1 answer
2k views

Is it recommended to have an ADS-B transponder in ALT mode on the ground? [duplicate]

Early on in training I was told that unless the airport specifically noted it on the chart, that the transponder was turned to ALT (altitude) mode just prior to taking the runway for take-off (lights, ...
Ron Beyer's user avatar
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7 votes
2 answers
3k views

Where are US FIS-B UAT ground facilities located?

In the US there are Flight Information Services Broadcast (FIS-B) transmitters strategically located to provide WX, NOTAMS and other flight information utilizing the ADS-B infrastructure. ADS-B has ...
mongo's user avatar
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7 votes
2 answers
2k views

What are Mode C requirements with ADS-B 978?

ADS-B out is available on the 1090 (Mode S) band, and can even be implemented as a firmware update to some Mode S transponders. In the case of 978 ADS-B Out, I believe that it is still necessary to ...
2NinerRomeo's user avatar
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7 votes
1 answer
795 views

Is this a glitchy ADS-B signal? [duplicate]

I was looking through my virtual radar logs one of the days and found this "glitchy" ADS-B behavior. I am almost 100% sure that this is not due to my antenna or setup since two independent different ...
KORD4me's user avatar
  • 1,779
7 votes
3 answers
310 views

TIS-B anonymous address

I could not understand what is the difference between ADS-R with anonymous address (CF=6, IMF=1) and TIS-B CF=5, which on ICAO Doc 9871 is described, for Version 1 as: Fine TIS-B Message AA field ...
nunojpg's user avatar
  • 201
7 votes
1 answer
157 views

Where does FlightAware obtain the filed flight plans under the "Flight Data" section?

Visit the FlightAware page for a random flight, say https://www.flightaware.com/live/flight/QFA570 Now under the "Flight Data" section, sometimes we'll see an entry called "Route" ...
iaexo's user avatar
  • 331
7 votes
2 answers
1k views

How does FlightAware correlate flights to Part 91 flight plan data?

I'm looking at some flights in FlightAware. With the scheduled air carrier flights, their call-sign can be crossreferenced with a flight schedule database to determine the origin and destination. How ...
BigNutz's user avatar
  • 529
6 votes
2 answers
2k views

What kind of ADS-B identification code is FFxxxx, where xxxx are numbers i.e. FF0024?

I live near an airbase and use an ADS-B receiver that picks up aircraft using regular ICAO assignments. They do not include flight path details or position info, but can be identified by the ICAO ...
Gordon's user avatar
  • 61
6 votes
2 answers
1k views

Why weren't SA-On GPS units updated to become SA-Aware?

SA = Selective Availability (gps.gov) SA-On and SA-Aware are widely used in current air transport aircraft (...) GPS that behave as if SA is still active (SA-On) GPS that behave as if SA has been ...
user avatar
6 votes
3 answers
245 views

NEXRAD—why is it 2D?

If you paid attention to NEXRAD training, you know that the colors of pixels show the maximum activity at any altitude in that air column. (It’s a “composite” view.) NEXRAD itself samples in three ...
Trey's user avatar
  • 250
6 votes
4 answers
4k views

What are the options for installing ADS-B OUT in a Cessna Citation to meet the regulations?

So I have a friend that works for a company that owns a Cessna Citation. His company is looking to comply with the ADS-B regulations. He has been given the task of making a business case for actually ...
JasonR's user avatar
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6 votes
2 answers
468 views

Can ATC provide vectors and separation service to and between IFR aircraft in areas where radar coverage does not exist using ADS-B only?

In the U.S., can ATC provide vectors and separation service to and between IFR aircraft in areas where radar coverage does not exist using ADS-B only? If so, are the separation standards the same as ...
user avatar
6 votes
1 answer
569 views

Is ADS-C used in practice?

Both the FAA and the EASA have decided against using ADS-C in the development of NextGen and SESAR, because of cost, scalability and ease of use. But has ADS-C actually been implemented and used in ...
usernumber's user avatar
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6 votes
3 answers
647 views

Would FAR 91.227, or any other regulation, forbid use of ADS-B-out in an unregistered ultralight?

In the US, would FAR 91.227, or any other regulation or law, forbid use of ADS-B-out in an unregistered ultralight? Could the N-number field simply be left blank, without violating any regulation or ...
quiet flyer's user avatar
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6 votes
1 answer
2k views

What's required for the ADS-B to function? A GPS or Mode S Transponder?

Jeppesen defines the ADS-B as a surveillance system broadcasting GPS-derived positions and other information such as velocity over the data link. Yet, the Wiki article on ADS-B relates it to the Mode ...
lemonincider's user avatar
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6 votes
2 answers
1k views

Why does the 1090 ES use the same frequency for both uplink and downlink?

The 1090 ES is the transponder system used in ADS-B. Why does the 1090 ES use the same frequency (1090MHz) for uplink as well as downlink? 1090 ES is an extension of Mode S. The Mode S used 1030MHz ...
Clive's user avatar
  • 383
6 votes
3 answers
123 views

ADS-B - Measure distance from position on ground to an aircraft

I have a docking station for autonomous drones in the field. It is equipped with a Raspberry Pi, an 1090 MHz ADS-B stick, and it knows it's geometric position from a previously done precise ...
user3792852's user avatar
6 votes
2 answers
520 views

When will the Canadian ADS-B satellite system be implemented?

It is interesting that ADS-B is not mandated in Canada as of yet. If you fly in the US you quickly realize the benefits. Now as I understand it Nav Canada is the largest shareholder in Iridum but ADS-...
P Kofman's user avatar
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