gps jammer

f you spend enough time trolling eBay for interesting electronic devices to take apart, you’re bound to start seeing suggestions for some questionable gadgets. Which is how I recently became aware of these tiny GPS jammers that plug directly into an automotive 12 V outlet. Shipped to your door for under , it seemed like a perfect device to rip open in the name of science.

Now, you might be wondering what legitimate uses such a device might have. Well, as far as I’m aware, there aren’t any. The only reason you’d want to jam GPS signals in and around a vehicle is if you’re trying to get away with something you shouldn’t be doing. Maybe you’re out driving a tracked company car and want to enjoy a quick two hour nap in a parking lot, or perhaps you’re looking to disable the integrated GPS on the car you just stole long enough for you to take it to the chop shop. You know, as one does.

But we won’t dwell on the potentially nefarious reasons that this device exists. Hackers have never been too choosy about the devices they investigate and experiment with, and there’s no reason we should start now. Instead, let’s take this piece of gray-area hardware for a test drive and see what makes it tick.

While the GPS constellation average altitude of 20,200 km (12,550 miles) might not be quite as high up as communication satellites in geosynchronous orbit, they’re still pretty far away. With this incredible distance in mind, and given the size of the antenna on most GPS-equipped devices, it’s no wonder that the received signal is very weak. So weak, in fact, that it’s generally below the noise floor. Only with clever algorithms and a dash of wizardry can your phone turn this whisper from the stars into anything resembling useful information.