In an article in the December 2019 issue of Scientific American, now available online, Paul Tullis looks at the problem of GPS hacking, or spoofing—how easy it is to do, how vulnerable GPS is to it, and the consequences we’d face if GPS was disrupted on a broad level. It’s essential but scary reading. The potential scenarios Tullis describes are far more serious than the instances of GPS spoofing we’ve seen so far. It’s not just about navigation: a lot of critical infrastructure relies on GPS timestamps.
Tullis points out that other GNSS systems have terrestrial-based backup systems; GPS does not, despite a 15-year-old directive to build an eLORAN backup that would put out a signal too strong to spoof.