ADS-B Question

[Cymru]

If DJI wants to have ADS-B Out capabilities, they could put the transmitter in the remote controller. As long as the drone can communicate with the RC, the RC could broadcast the drone's location. That would move the weight and power issues from the drone to the RC. I don't know how practical it would be to build it (cost, power, weight), and you would find drone operators who would not want to broadcast their drone's location. But it could be done.

Then as well as frequency congestion (that does exist) you also have the fact you're still going to need each drone individually registered with the ICAO as well as local bodies, unique hex identifiers needed for each one and so on.
Given the low altitudes, ranges and speeds consumer drones operate on ADS-B is a very inefficient way of doing it.
Something like UAT would make slightly more sense given its design but again, its overkill.

It would never deter people who want to break rules. You can spoof ADS-B with a $30 raspberry Pi plugged into a HackRF to be anything/anywhere/any speed you want.

 

[Cymru]

I think unmanned deliveries might be what it takes to take to bring ADS-B transmitters down to commodity pricing. Taking everything else off the table, having bi-directional ADB-B on delivery drones would keep them from colliding into each other. If you through enough money on a technical problem, the resolution becomes cheap.

Delivery drones are not going to need ADSB. They're not going to be operating in controlled airspace outside defined corridors and so on.
Far more useful to them would ne active detect and avoid - a data link between drones themselves to not just detect but negotiate and predict to allow avoidance.
ADS-B (/S coupled with TCAS etc) is very sub optimal for this sort of traffic.

 

[lookout]

Problem with mode C is its going to give you nothing more than a squawk code you cant do anything with and a coarse altitude to within 100ft or so. It wont give you any positioning data at all.
Tracking sites need to use fairly complex maths and multilateration from many receivers to actually get a coarse location for a Mode C (or A) contact.
You'd still have the issue at low level where drones are (hills, valleys, obstructions) of not picking up a signal at all until its almost on top of you.

That's how LORAN worked. But they've done away with it, but there are others that want to bring back the ground based system back. So now they're gonna put up a bunch of ADS-R ground stations.

Some ideas never go away.

But the other day I kept getting an aircraft the repeatedly goes over that most likely took out their mode C and replaced it with mode S after 9/11. Then ADS-B comes along and all you get on 1090 is Mode S. Well now, with a dual band receiver, they left the mode S transponder in, but added ADS-B on the UAT 978 and position came off there. Weird things with that ADS-B. So if you're using 1090 only, you might not being seeing everybody you want to avoid.

ADS-B can be seen for several miles away or not be seen until right on top of you. So ADS-B isn't quite reliable, it can help but not everyone is on it either. And they want to squeeze everybody together like rush hour. Radar separation is just that and leaves a comfortable distance.

Mode A/C was only concerned with identifying a bogey or friendly during the world war times. Then it was adopted for average everyday flight combined with radar. Looking for someone at altitude even if no position at least gives something useful. But they never implemented a mode C in, before now and even mode S wasn't position either.

 

[maelstrom]

ADS-B can be seen for several miles away or not be seen until right on top of you. So ADS-B isn't quite reliable, it can help but not everyone is on it either.

But better anything than nothing!

And they want to squeeze everybody together like rush hour. Radar separation is just that and leaves a comfortable distance.

They’re not squeezing any more aircraft into the airspace than were already there. They’re just improving situational awareness in order to make operating in the airspace safer. Radar services are much more restrictive and limit what you’re allowed to do in the airspace.

 

[Cymru]

Plenty of places don't have radar service either.
Some are using ADS-B as a semi-official traffic advisory.