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# High Precision GPS

Sometimes important changes for our industry come from outside the industry. We’re getting close to seeing affordable GPS devices that can measure accuracy within a centimeter. Higher precision GPS will be invaluable for ISPs and broadband technologies.

Normal GPS isn’t highly accurate. For example, a GPS-enabled smartphone is only accurate to within 4.9 meters (16 feet) under the open sky. Accuracy is even less around tall buildings, trees, bridges, or other obstacles that can block or deflect signals from satellites. This is plenty of accuracy for providing driving directions, which is the use of GPS that most people are familiar with – although occasionally you’ll get bad driving directions in a major city center when your mapping software thinks you’re on a different street.

Applications like using GPS for driving directions use a single frequency with the GPS device (smartphone or car) connecting to a single GPS satellite. The GPS satellites operated by the government can theoretically provide greater accuracy within 2.3 feet. But accuracy is reduced by local factors such as atmospheric conditions, signal blockage, the quality of the receiver, and the position of the satellite in relation to the user. All of these factors contribute to the lessened accuracy for the normal cellphone or car GPS unit.

High-precision GPS has been around for a while. But the current generation of high-precision technology has not been suitable for applications like driving. High-precision GPS devices work by using multiple frequencies and connecting to two GPS satellites. The technology uses complex mathematics models to calculate precise locations. This would normally require three signals (triangulation), but the devices do a good job at determining position based upon two signals. High-precision devices are also expensive to operate, with an annual subscription as high as \$1,000 per device.

The new generation of GPS devices will overcome several of the major shortfalls. The new devices do away with the need for two frequencies. That limitation meant that high-precision devices still won’t work while moving in a car – the needed mathematical calculations cannot keep up in a receiver that’s moving.

The new devices instead are using a clever solution. Each device can create a real-time model of the environment that incorporates all of the known factors in the region that affect GPS accuracy. In essence, a single cellphone is preloaded with a simulation of the GPS environment, and the cellphone can then correct for expected distortions in the GPS measurement – meaning much higher accuracy in locations. These regional models are updated during the day to account for changes in temperature and weather and are beamed to any device trying to use GPS.

Higher precision to GPS opens up applications that were unattainable in the past. The simplest application will be precision locations for things like handholes. Technicians will no longer need to search through tall grass along a rural road to find a handhole because with the new GPS they’ll know the exact location.

Better GPS will be invaluable in locating existing utilities and in siting new buried construction. An engineer that first walks a route can define exactly where to dig or where to place a buried fiber.

Better GPS will be invaluable to rural broadband services like precision agriculture. Once a farmer precisely maps a field, they can tell a self-driving tractor or harvester exactly where to drive without needing a driver in the cab of each device.

And better GPS will help daily work functions in numerous ways we will discover once it’s routinely available. Somebody will be able to survey a site for a new hut and precisely define the location of a concrete pad or a fence without having to return to oversee the construction process. Companies will be able to precisely tell a homeowner where to find a buried conduit without having to always wait for a locator. We’ll quickly get used to more precise field measurements just like we all quickly adapted to trusting GPS driving directions.