Most people know about GPS. It’s on our cellular phones, in our cars and seems to be omnipresent in technology. What really is GPS? How does it work? Why does it work in some situations but not in others? These are some of the questions I’m going to address today. GPS is a more complicated system than some people realize and I want to shed some light on the subject.
GPS stands for “Global Positioning System”. The system consists of 24 satellites orbiting the earth everyday. Where did they come from? These satellites were originally put into orbit for military use by the United States Department of Defence. In the 1980s they were made available for use by the public. Since then, GPS devices have been a booming industry. Think of the Personal Navigation Devices in cars. Or the mapping capabilities of your phone. There are still other positioning satellites out there – GLONASS (Russian) and the planned upcoming Galileo Positioning System being developed by the European Union. There is also the American Standard Global Positioning System, still the strongest player in the commercial market.
So now that we know what GPS is, how does it work? With 24 GPS satellites in orbit, a standard hand-held GPS device needs to have a clear line of sight to 3 satellites to generate your location on the planet. This uses a fundamental principal called Triangulation. Your device, be it a tour app or a bus, sends out a ‘ping’ to the satellites. When the Satellites receive that ping, they transfer the data (how long the satellites took to receive the message) to a Monitoring station. The Monitoring station then relays the location back through the satellites and to the device to tell it where it is positioned. This all happens in the blink of an eye.
In our case, we use GPS for our commentary systems. Our GPS receivers lock signals with several different satellites orbiting the Earth. This allows us to play commentary at precisely the right moment on sightseeing routes worldwide.
Occasionally something happens to make your GPS unavailable. Normally you may notice your device states “GPS Searching”. GPS Satellites can normally see through “soft” materials, while being blocked by “hard” or “reflective’ materials. As an example, a GPS signal can easily penetrate vinyl, but has a much harder time penetrating a metal roof. This can show itself in a variety of ways, and ‘hard’ or reflective materials are found in a lot of unexpected places. Large buildings are obvious, while not many people know that tinted windows contain metal that can block GPS signals. You always need to be aware of location when you are holding or installing a GPS device or antenna.
GPS is a great technology for a lot of different applications and is a perfect tool for almost any outdoor tourism application. Just look at the way GPS has changed the way we travel - with devices like Garmin or applications like EveryTrail.