Invented by the U.S. military in the early ‘70s, use of the Global Positioning System (GPS) was restricted to government entities before the last years of the Reagan administration. The general public has been allowed to use GPS since the late 1980s. The long-running joke about adult males driving aimlessly for hours because they were too proud to ask directions has faded from the collective mind. All sorts of electronic devices, from cars to smartphones, have a GPS chip built in. But how does GPS actually work? And is it a force for good, or are there ulterior motives at work?
Orbiting the Earth are a series of 24 to 32 satellites, each containing a precise atomic clock. The satellites use these clocks and their position, with a series of the same clocks on the ground, to synchronize their position relative to each other with great accuracy. Using these known positions, the GPS receiver in your smartphone gets a signal from at least four of these satellites, calculates its position relative to the satellites, and then uses internal mapping software to show you where you are.
When you ask your iPhone to give you directions to the hardware store, your phone asks the satellites for a position check, the data is retrieved from them, and you see it’s five miles away with a preferred route. That’s the good news.
The bad news is that with GPS enabled (in car or phone), other entities can track your movements. If you have downloaded a weather app, you were asked for permission to find your location. This makes sense, as you most likely want to know what the weather will be where you are at the moment. However, what does the app’s maker do with that information? Are they reselling it to marketers? Using it to build a database of folks in the area to send weather warnings? Can it be put to even more nefarious use?
The answer is that you don’t really know where your GPS data winds up once it leaves your electronic device. You can restrict its usage, however. In Settings on your computer or phone, find the section in Privacy that talks about Location. Review the apps that have requested access to location data (GPS). If an app or system service says it uses “Location services” and you can’t think of any good reason why, disable it.
While you can disable Location Tracking altogether, you may find that this disables the helpful features of GPS, such as directions to avoid traffic tie-ups, warnings about severe weather or the Find My Phone feature.
Using GPS to send ads to your computer or phone is commonplace. Retailers now use the free WiFi in stores along with your phone’s GPS to send you targeted ads while you shop. These may be pop-ups in your web browser, or even notifications on your locked screen.
In most cases, if law enforcement wants access to GPS data, they need a search warrant. This protection is still being argued in the courts, though. And in some cases, phones seized during arrests are searched under “probable cause” statutes without a warrant.
A good question to ask yourself: How much of your privacy you are willing to surrender to use the good stuff, without making the marketers’ job any easier?