Answer: Balloonists

The GPS unit in your phone, car, or stand-alone navigation device has security regulations built in that you, outside of this trivia question or your own trivia gathering adventures, would never discover under ordinary circumstances.

As part of regulations designed to ensure that GPS technology isn’t used in weaponry, manufacturers are required to design their consumer GPS devices so that the device does not function if it is moving over 1,200 mph (1,900 km/h) and/or at an altitude of 59,000 feet (18,000 meters) above sea level or higher. Clearly, you’re not going to hit that speed or elevation limit with the Garmin mounted on your car’s dashboard, but it helps ensure that if anyone tries to wire an off-the-shelf GPS module into a missile, it won’t be able to use it for navigation.

Even though that limitation doesn’t affect most of us in the slightest, there is, however, a tiny group of dedicated hobbyists who have run into it: high-altitude balloonists. You know all those cool videos you can find on YouTube of people sending GoPro cameras (and often action figures or LEGO minifigs as pilots) into the highest reaches of the atmosphere? Their efforts to track and locate their balloons are often hampered by their GPS units shutting off once the balloon has drifted up above 59,000 feet.

The limitations of the devices are referred to as the “COCOM Limit” in reference to the Coordinating Committee for Multilateral Export Controls (CoCom), a Cold War era committee formed by the Western bloc powers after World War II to impose an arms embargo on the Soviet Union and sympathetic countries. Although CoCom was replaced by the Wassenaar Arrangement (another arms control and embargo agreement), the acronym stuck as a quick shorthand reference to the kind of security restrictions found in commercial GPS units.