GPS

We have long yearned to know where we are on the planet. This was of particular importance to sailors when at sea. Primitive early sextants, under ideal conditions, gave an accuracy of about 2 miles, while modern gyro mounted units can get within 200 meters.

So, consider the modern miracle that most of us carry around every day, that can give us our location on this planet to within 3 feet, or even our location in the sky above. How extraordinary !!

This is made possible by the GPS (Global Positioning System) of 33 special satellites and a tiny Intel GPS chip and software buried within our phones.

The first GPS (called TRANSIT) was used by the US Navy as early as 1960. It relied on just 4 satellites and could only give an accurate position every 2 hours. By 1978, the satellite constellation had grown to 10 and NAVSTAR could give near continuous position readings, which were only usable by the US military. In 2000, when the current constellation of 33 was complete, Congress forced the military to open the system to civilians. Still, GPS receivers were costly and bulky (think the old “brick” cell phone. The GPS is managed by DOD and has thus far cost about $6 billion (since 1960). In my mind one of the few military expenses that are worthwhile.

The huge and world-changing breakthrough came in 2008, when Intel introduced a tiny and relatively inexpensive GPS receiver chip. The iPhone 3 was the first model to include the feature, followed quickly by many Android devices. There are also dedicated GPS receivers. All use information from a minimum of 4 satellites, plus cell tower information to (almost) instantly tell you exactly where you are on the Earth, on the sea or in the air. I say almost, since the device needs a few minutes after it’s turned on to acquire sufficient satellite data. Hikers especially appreciate the security of knowing where they are in the woods, though the devices are most accurate in urban settings with multiple cell towers in range.

In my Peace Corps service working on rural water systems, an iPhone App allows me to track and record GPS position and elevation and print them out over a map. This has proven an invaluable tool in planning, repairing and estimating materials for these community systems.

So, next time you turn on your smartphone navigation app (or tracking app that allows you to record a path over time) show a little appreciation for the incredible technology that makes it all happen.