The global positioning system is one of the most important tools we have right now. Ships use it to navigate trading routes. The military uses it to get around. Heck, most of us use it to get around; in fact, if you call 911 on your smartphone, it likely uses e911, a system that uses GPS to lock onto your signal.
So, it’s not exactly heartening to discover that some idiot with a device you can get for about eighty bucks can knock out the GPS signal for blocks. Yep, GPS is highly vulnerable, and as we become more dependent on it, and as everybody from guys who want to slack off on the job to tyrannical governments trying to troll their neighbors start blocking it, that’s starting to be a serious problem.
The main problem is that GPS signals are relatively weak. It makes sense: They are sending signals from miles away in space, and adding to the problem is that there’s a lot of signal traffic as more of us get GPS devices and more GPS chips are installed in everything from cars to smartphones to small children.
So what can we do? Honestly, not that much, for now. Blockers are fairly discreet, and in fact in the US owning one is completely illegal. Governments are building terrestrial systems to provide navigation when GPS fails. These range from upgrading World War II-era technology to some really neat work by DARPA, creating a chip that uses sensors to figure out exactly where it is without needing any sort of signal; it’s basically a sense of direction you can install.
But until then, essentially you have to hope that you’re not near North Korea, which uses truck-sized jammers mostly to be dicks. Or a delivery guy who doesn’t want to get busted by his boss.