Finding Your Location with the Global Positioning System

GPS Origins, Position Measurement, Errors, Accuracy,
GNSS around the World, Applications, and Geocaching

Here’s something for you to think about. You’re out hiking in a forest. A storm comes up, and you quickly take shelter well off the trail. When things are all clear, you’ve gotten completely disoriented, and you can’t find your location: you’re well and truly lost. Or consider this. You’re driving in unfamiliar territory. It’s late at night, you’re miles from anywhere, you missed an important turn a few miles back, and none of the names or route numbers on the signs mean anything to you. In both cases, you’re out of cell phone range, and even though you have a printed map, you really have no idea where you are. How do you start navigating yourself out of this mess?

A few years ago, situations like these could have been potentially disastrous, but today there’s a geospatial technology tool that’s ready and available to help get you out of these situations. Using a small, hand-held, relatively inexpensive device, you can find the coordinates of your position on Earth’s surface to within several feet of accuracy. Simply stand outside, turn the device on, and shortly your position will be found, and perhaps even plotted on a map stored on the device. Start walking around, and it’ll keep reporting where you are and even take into account some other factors like the elevation you’re at, the speed at which you’re moving, and the compass direction in which you’re moving. Even though it all sounds like magic, it’s far from it—there’s an extensive network of equipment across Earth and in space continuously working in conjunction with your hand-held receiver to locate your position. This, in a nutshell, is the operability of the Global Positioning System (GPS).

GPS receivers have become so widespread that they seem to be everywhere. In-car navigation systems have become standard items on the shelves of electronics stores. GPS receivers are on sale at sporting goods stores too, because they’re becoming standard equipment for campers, hikers, fishing enthusiasts, and golfers. Runners can purchase a watch containing a GPS receiver that will tell them their location, the distance they run, and their average speed. Smartphones will often have GPS capability as a standard function. Use of the GPS is free for everyone and available worldwide, no matter how remote the area you find yourself lost in. So the first questions to ask are—who built this type of geospatial technology and why?