A talk from the hacker conference 39C3 about the Baltic Jammer (which causes GPS interferences in the baltic sea) and how a civilian project plans to protect against it with existing infrastructure. (in English)
I live in a suburb to the north of Stockholm, I have experienced the GPS jamming first hand.
There were a few days when my car’s inbuilt GPS thought I was driving around in another suburb on the other side of the city.
Does anyone know if GPS has the abillity to do signed packets?
I mean, I’d rather the GPS fail completely, than giving me false data.
Civilian-use GPS signals are unencrypted specifically because they want to be as open as possible. It was originally a military only system, that was only opened up in 2000 after a civilian airliner blundered into Russian airspace and got shot down.
Military-only signals are encrypted. There are also newer civilian-only signals with checksums and on alternative frequencies but there aren’t enough of the new sats up yet to live on it fully. Check whether your phone supports dual-band GPS, or specifically the L5 signal. There are even apps you can download that will display the full output of your GPS chip, including every satellite in view.
Pretty sure that gps is a plaintext broadcast. It’s nice because it’s universally accessible, but it’s a target now that people rely on it.
Back in the 90s my head was full of maps of my region because I drove a lot for work. Mobile online GPS is a game changer, since you get traffic updates in real time. While I suppose you could review your route ahead of time, there is not a known way to get relevant traffic updates unless you have a radio station just to that effect.
My real concern for you would be a sudden information blackout.
At least, it did not tell you, you were in Kaliningrad… 😉

