ABDS-B Out boiled down?

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Sundancer

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ADS-B out: Someone set me straight where I'm wrong on this? And I'm only interested in ADS-B out, UAT for below FL18. Not addressing ADS-B in, or the space-based stuff or surveillance radar parts of ADS-B.

1. Legacy transponders (and new ones) blast away on 1090 mhz

2. For ADS-B out via UAT we transmit a bunch of data on 978 mhz - this includes the same data transponders transmitted before ADS-B, plus position, N number, and other stuff I don't care about.

4. The new WAAS enabled transponders handle it all - assembling AND transmitting the data.

5. For legacy transponders something like a GDL82 or a Skybeacon eavesdrops on the transponder and combines the transponder data with a built in WAAS source, and transmit it independent of the transponder.

6. A few hundred ground stations listen for the signal and pass the data to ATC. Their equipment stirs in with their other sources to get the big picture.

Looking for the GA pilot's basic need to know - functional understanding.
 
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Sundancer said:
ADS-B out: Someone set me straight where I'm wrong on this? And I'm only interested in ADS-B out, UAT for below FL18. Not addressing ADS-B in, or the space-based stuff or surveillance radar parts of ADS-B.

1. Legacy transponders (and new ones) blast away on 1090 mhz

2. For ADS-B out via UAT we transmit a bunch of data on 978 mhz - this includes the same data transponders transmitted before ADS-B, plus position, N number, and other stuff I don't care about.

4. The new WAAS enabled transponders handle it all - assembling AND transmitting the data.

5. For legacy transponders something like a GDL82 or a Skybeacon eavesdrops on the transponder and combines the transponder data with a built in WAAS source, and transmit it independent of the transponder.

6. A few hundred ground stations listen for the signal and pass the data to ATC. Their equipment stirs in with their other sources to get the big picture.

Looking for the GA pilot's basic need to know - functional understanding.
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Ignoring all the stuff you said to ignore, I think you've pretty much got the gist of it.
 
Take a look at ADSBexchange.com. All the data fields are there, it’s a surprising amount of information.
 
Regarding # 6. I was always curious if it goes to ATC (specifically) or some other new govt program that ATC then elects to view it or not.

Edit: Whatever it is, I know it merges non ADSB out data as well for GBT transmission if that non out plane is on FF or IFR plan. Seems like ATC would see that plane twice then, once from their radar and again from the ADSB out feed (which is IN - sorry)
 
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What data does a legacy transponder (without ADSB) send? Squawk code of course, altitude if mode C, aircraft ID if mode S? So an all-in-one ADSB like a Skybeacon I presume gets the altitude info (and squawk?) by eavsedropping on the transponder and rebroadcasts that in its data package, is that correct?
 
Didn't ADS-B go live like two years ago.....and many of us have been using it a few years before that? o_O
 
It did go up a while back, correct: I have (I think) a gross idea of what's going on in our airplanes in order to comply. Listening here in case my understanding is off base. As I plane shop I want to be clear on the hardware options for compliance. It's a NextGen (SomeDayGen?) thing, a hoop we have to go through. If I have to add hardware to a plane I want to take the simplest route based on what boxes I inherit.

Dana said:
What data does a legacy transponder (without ADSB) send? Squawk code of course, altitude if mode C, aircraft ID if mode S? So an all-in-one ADSB like a Skybeacon I presume gets the altitude info (and squawk?) by eavsedropping on the transponder and rebroadcasts that in its data package, is that correct?
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That's my understanding.
 
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Sundancer said:
Not addressing ADS-B in, or the space-based stuff or surveillance radar parts of ADS-B.
...
Looking for the GA pilot's basic need to know - functional understanding.
Click to expand...

All of the components are basic need-to-know.

Short answer:
  • UAT ADS-B transponders transmit on 978; other ADS-B transponders transmit on 1090. Both require GPS. Implementations vary.
  • Ground stations uplink weather and traffic, including mode C traffic. Ground stations also relay traffic across bands as needed.
  • Receivers can receive traffic directly from other air targets and/or uplinked from ground stations.
https://www.faa.gov/air_traffic/technology/equipadsb/capabilities/ins_outs
 
Sinistar said:
Seems like ATC would see that plane twice then, once from their radar and again from the ADSB out feed (which is IN - sorry)
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That can happen to you if you have ADSB In. You get a report of an aircraft REAL close. Which is you a few seconds ago. It can get your attention. :D
 
Pinecone said:
That can happen to you if you have ADSB In. You get a report of an aircraft REAL close. Which is you a few seconds ago. It can get your attention. :D
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Ain't that the truth! Especially when he's on your six and you can't see 'em or shake 'em! :eek:
 
Yeap, happened to me a few weeks ago. About to enter the pattern and POOF, right behind us, same altitude, almost the same heading. Turned away and climbed and it followed. Then gone.

A few minutes later, got my heart rate under control.
 
Wildhorsetrail said:
Does uplink ADS-B in show mode C traffic not equipped with ADS-B out? This would only work in a radar environment.

Sent from my SM-A326U1 using Tapatalk
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Only in a radar environment and when you can receive TIS-B signal from ground station (and traffic is in your “hockey puck”)
 
Wildhorsetrail said:
Does uplink ADS-B in show mode C traffic not equipped with ADS-B out? This would only work in a radar environment.
Click to expand...

Yes, when I had my Starduster which had mode C but no ADS-B, people around SNC (not what I think of as a "Radar environment" but I guess there's coverage from nearby radars) could see me on their ADS-B in.
 
What plane are you shopping for? As ADSB has been mandated for a few years now, chances are a plane you would look at would have ADSB out already if it needed it.
 
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Sinistar said:
Regarding # 6. I was always curious if it goes to ATC (specifically) or some other new govt program that ATC then elects to view it or not.

Edit: Whatever it is, I know it merges non ADSB out data as well for GBT transmission if that non out plane is on FF or IFR plan. Seems like ATC would see that plane twice then, once from their radar and again from the ADSB out feed (which is IN - sorry)
Click to expand...

ATC sees a merged view from all the various available surveillance sources, so secondary radar is one source but there may be multiple radar sites and if ADS-B Out equipped, presents a second source. All the sources get merged together and displayed as a single target to ATC.
 
John Collins said:
ATC sees a merged view from all the various available surveillance sources, so secondary radar is one source but there may be multiple radar sites and if ADS-B Out equipped, presents a second source. All the sources get merged together and displayed as a single target to ATC.
Click to expand...
Is this true at all ATC facilities?
 
I believe that all TRACON have been move to the STARS system and in the CONUS the ARTCC use ERAM. I understand these systems used by ATC support FUSION which integrates the various surveillance sources including Terminal Radar, Enroute Radar, ADS-B, and WAM. STARS is the Standard Terminal Automation Replacement System and ERAM is the En Route Automation Modernization System. WAM is Wide Area Multilateration System that determines aircraft position by triangulation of the transponder reply time of arrival at several WAM station locations.
 
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