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Un touriste arrêté en Inde pour possession d’un GPS de vélo (mais, rassurez-vous, libéré après)
https://weelz.ouest-france.fr/inde-un-touriste-emprisonne-pour-possession-dun-compteur-gps-velo/
Y’a un énorme truc qui me chiffonne : ça parle du GPS comme un "émetteur satellite".
Les "GPS" sont des récepteurs bon sang. Ils n’émettent rien. Un petit engin comme cela ne peut pas envoyer un signal à des satelittes qui sont à 20.000 km d’altitude ! C’est beaucoup trop loin. Et imaginez que le satellite doivent gérer des millions de connexions ?
@ploum Of course you area absolutely correct that GPS receiver is ... a receiver.
But I'd still want to point out that is is absolutely possible to make pocket sized transmitters that can reach satellites.
Benefits of large antenna in space / beam forming / coding gains / ....
It wouldn't be fast or anything, but for instance, apple sms over sat, or distress beacons, ...
@tnt : those are satellites that are often less than 1000km away. GPS are at 20.000km ! This requires lot of power.
@ploum No it doesn't ... I've got a phone the size of that bike GPS that can transmit over a geo sat that's almost twice as far.
You can trade off speed for transmission gain. Or bigger antenna on the sat ( foldable, multi-element for beam forming ).
See Huawei’s Mate 60 Pro for instance.
Also the latest Beidou satellites ( china GPS ) actually include a SMS service !
@tnt : wow, I didn’t know that. Thanks for the info.