ADS-B much, MUCH better coverage than we thought?

[EpicFlight]

Just read a very detailed article on ADS-B and learned some things I didn't know that makes it sound like ADS-B is a much more accurate and comprehensive picture of local air traffic than I, any many others here thought.

In short, if you receive ANY ADS-B traffic, you are almost certainly seeing all the traffic within a 15 mile radius (approximately). Regardless if an aircraft in that space is carrying an ADS-B Out transceiver or not, so long as your in an area with radar coverage, and an ADS-B ground station. This is true the vast majority of drone flights, and where it's rural enough to be outside any radar, collision risk is WAAAAAAYYYYYY less anyway.

Here's the relevant portion of the article (link):

 

[EpicFlight]

Of course the big caveat is receiving transmission from an ADS-B Out equipped aircraft. If you're not, the skies around you could be dense with aircraft, and you wouldn't see it in DJI Fly.

So, it's no guarantee. No substitute for your eye and ears. As an additional safety and awareness tool, I just found out that ADS-B is much more informative than I thought.

 

[waltermitty]

Huge percentage of planes are 40-50 years old. Older yet include those like Piper Cubs or kitplanes owned by enthusiasts and which may not possess (or required) to have ADS-B. I know that Flightradar-24 will offer free ground kits if you request and live in a location which is ADS-B ground station sparse. In the end, there is much patchwork bits and pieces that make up the theoretical picture of what the ADS-B system can become. We're getting there but there are still many holes.

 

[EpicFlight]

Huge percentage of planes are 40-50 years old. Older yet include those like Piper Cubs or kitplanes owned by enthusiasts and which may not possess (or required) to have ADS-B. I know that Flightradar-24 will offer free ground kits if you request and live in a location which is ADS-B ground station sparse. In the end, there is much patchwork bits and pieces that make up the theoretical picture of what the ADS-B system can become. We're getting there but there are still many holes.

you need to read the article again.

Those older planes show up on radar. They will then be included in the ADS-B Out data stream from any plane with an ADS-B Out transceiver.

The discovery, and point here is that in many instances an ADS-B receiver can show aircraft that have no ADS-B equipment at all.

Heck, if your drone showed up on radar and was tagged (rather than being ignored and filtered out) it would show up on another DJI drone's ADS-B traffic.

 

[waltermitty]

Okay, perhaps I'm not understanding this properly. If the plane is not equipped with a transponder who/what device paints this ID and passes it on for ADS-B identification?

 

[EpicFlight]

Okay, perhaps I'm not understanding this properly. If the plane is not equipped with a transponder who/what device paints this ID and passes it on for ADS-B identification?

It doesn't have to be identified for radar to pick it up and track position, speed, and altitude. The point here is an aircraft does not need to have ADS-B to be tracked in ADS-B traffic data, and – what was new to me – aircraft with simple air-to-air ADS-B receivers (Air 2S) receiver ADS-B ground station traffic data forwarded by aircraft with an ADS-B Out transceiver.

 

[waltermitty]

I think this may require a little more back and forth (and a primitive drawing or two) than I can manage through typing on a small smartphone keyboard so I will leave it be....though I will reread the link again and have a second cup of coffee

r- (fixed wing pilot, including aerobatics)

 

[EpicFlight]

As a fixed-wing pilot surely you know all traffic detected by radar, whether squaking an ID or being silent, is displayed and tracked.

If something produces a big enough radar return, it's displayed. It would be dangerous otherwise.

Anything being tracked by local radar will be included in the traffic data broadcast by an ADS-B ground station, if there is one in the area. This will then be broadcast to any aircraft carrying an ADS-B Out transceiver, and then broadcast by that aircraft over ADS-B air-to-air link.

So, under the circumstances where there is local radar, a ADS-B ground station, and an aircraft nearby with an ADS-B Out transceiver, ADS-B receivers will acquire a complete picture of local traffic.

In practice these conditions are met nearly 24/7 in any urban locale with an airport with an active tower.

 

[Cw4bray]

As a Commercial pilot and former ATC specialist I can say this thread's not accurate. For example, in the North and South Dakota area, primary and secondary radar is unavailable below 4000' .It doesn't exist. Unless there's a military AWACS plane painting the area and somehow microwaving a signal straight to the internet, which I doubt ever happens, you're not going to see any traffic on ADS-B regardless of the aircraft being equiped with a electric system. Also, you'd be amazed at the number of pilots flying - cruising below 500' which is stupid, and some of those wouldn't be seen even on approach control radar more than five miles from the airport.