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Active RFID tags do exist, but they're basically just a wireless transponder with a battery. Satellite tracking probably exists but it would need a fair amount
by GaryNumanVevo 2y ago
Active RFID tags do exist, but they're basically just a wireless transponder with a battery. Satellite tracking probably exists but it would need a fair amount of power and a non-noisy RF environment.
- akira2501 2y ago> fair amount of power My favorite thing about GPS is all satellites broadcast on the same carrier frequencies and the received signal at the surface of the earth is several dB below the noise floor. Which you can do with complicated signal encoding involving known values at the receiver and a really slow overall bitrate on top of a much faster carrier.
- eru 2y agoThere's more to it: they increased the overall accuracy (and I guess implicitly the bitrate?) over time much further than was originally intended, by more clever electronics and math on the receiver.
- RF_Savage 2y agoFor passive tags the power densities and antenna sizes in orbit would be genuinely use. For active tags it's a transponder like any other satellite tracker.