I don’t know how air tags even work. So they have a cellular connection or something? How are they able to be tracked?
They’re Bluetooth beacons. Basically they transmit a very low power signal that any nearby iPhone (I think Android phones do it too now, but I’m not certain) can pick up. When a phone receives the signal it sends the information about the tag and the phone’s current location to the central server. You can then track the tag from there.
Crowd sourcing. AirTags and other similar trackers emit weak, short range Bluetooth beacons that any iPhone can quietly detect and report along with where they were when the beacon was seen. There are privacy implications for sure, but it works.
They use a combination of Bluetooth and nfc and maybe some wideband spec (though I think the wide and stuff is just for when you go in searching) . Basically anytime it’s near another iPhone, the iPhone picks up the tag ID and sends it in.
If it detects a lot of checkins to a phone that isn’t on the same Apple ID, the AirTag will make noise (as an anti-stalking measure)
I believe a recent patch also allows android to report in status, or maybe that’s coming but still in the works. Not sure.
Android won’t track airtags, but will allow 3rd party tags to work via “find my phone” (becoming “find my device”). They have coordinated with Apple however for anti stalking measures. Both can detect longer term presence of each other’s tags, and sound a warning. Apparently they have delayed the release, to allow apple to implement the protocols properly before they do.
Google’s are simple BLE beacons. They ping out periodically, and any android phones nearby note and report its existence and strength (along with their location).