• Psythik@lemmy.world
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      8 months ago

      Next time you’re on a flight, download a GPS speedometer app and launch it right before takeoff. You’ll notice that it’ll accurately measure the plane’s speed up to around 500 MPH, before it suddenly stops giving you a speed readout.

      Like the other person said, this is to prevent your average dude building a guided missile using an old phone they have lying around.

      • MeanEYE@lemmy.world
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        8 months ago

        It’s a built-in security of the protocol. For accurate speed measurement device would need access to L2 frequencies, which carry encrypted data used for additional corrections, faster calculations, atmospheric conditions, etc. One can certainly get a location tracked through phone, but it’s not solely though GPS, it’s most likely combination of other positioning systems.

        • deur@feddit.nl
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          8 months ago

          Probably would just use an IMU exactly as the plane itself already does for its own navigation.

          They get a lock on the ground, synchronize the IMU with the Earth’s orbit, and they keep track of where they’ve moved from the origin, supplemented by GPS.

    • MeanEYE@lemmy.world
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      8 months ago

      You are welcome. Although, like I said in other reply, speed is not the only limiting factor. It just makes it harder to find location. There are number of other things.