It's not at all comparable. ADS-B is opt-in: you place an ADS-B out transmitter in your plane and turn it on to transmit your position [1]. You're perfectly free to turn your ADS-B off if you like. It's not even required for most of the US, so some planes may not have it installed (ADS-B out is only required within 30 nautical miles of a Class B airport [big airport], inside Class C airspace [medium-size airport], or in Class A airspace [18,000 ft above sea level]).
Military aircraft don't use ADS-B out a lot of the time. Spy planes are obviously not going to transmit their locations. A civilian plane with an electrical failure might stop transmitting ADS-B out. Being able to identify planes via satellite is a whole separate capability.
[1] In all the planes I've flown, ADS-B is configured to transmit whenever the master electrical switch is turned on, but it can be configured to be turned on and off at will. See this video on a mid-air collision involving an eccentric character who liked to fly with ADS-B out turned off: https://youtu.be/G5y3JiOEnVs?si=rs5gNMurZ9ssUloS. If I recall correctly, he had his ADS-B wired to his nav lights so he could turn it on and off at will.
From my experience in general aviation, I've never met anyone who intentionally turned off their ADSB. It is generally wired into the transponder, and the bulk of air traffic worldwide happens where a transponder is practically required. Yes, it is technically not needed but you can't get help from ATC, can't fly instruments in the clouds, and you can't fly high.
Sure, it can happen but these are edge cases. Space-based ADSB solves this problem with a fraction of the effort and much better data. Spooks might need this for military stuff, but for the bulk of planes, it doesn't make sense.
You are NOT at all (legally) free to arbitrarily turn off your ADSB on an aircraft equipped with it. 91.225(f) [1].
> Except as prohibited in [unmanned aircraft section], each person operating an aircraft equipped with ADS-B Out must operate this equipment in the transmit mode at all times unless [authorized by FAA or ATC].
A common way to add ADSB to an aircraft not originally equipped is replacing one of the lights with a uAvionics skyBeacon[2], which has a LED light + ADSB-out transmitter. So the nav light switch would control it, but you'd also now be required to have them on at all times.
ADS-B is mandatory in many jurisdictions and for all commercial flights basically everywhere. Obviously like any transponder, you can pull the breaker, but turning it off is likely to beer the end of you're commercial piloting career.
That video is great, thanks. Though the ML solution doesn't seem to claim to be able to identify individual aircraft, just do daily counts of aircraft at specific airfields. Which I guess works for military aircraft, but I guess if you're a nation state actor you've already got this sort of technology/intelligence?
Military aircraft don't use ADS-B out a lot of the time. Spy planes are obviously not going to transmit their locations. A civilian plane with an electrical failure might stop transmitting ADS-B out. Being able to identify planes via satellite is a whole separate capability.
[1] In all the planes I've flown, ADS-B is configured to transmit whenever the master electrical switch is turned on, but it can be configured to be turned on and off at will. See this video on a mid-air collision involving an eccentric character who liked to fly with ADS-B out turned off: https://youtu.be/G5y3JiOEnVs?si=rs5gNMurZ9ssUloS. If I recall correctly, he had his ADS-B wired to his nav lights so he could turn it on and off at will.