Getting To Know GPS Technology
Getting To Know GPS Technology
Once upon a time, this would have sounded like a science-fiction plot: We're going to put an array of machines up in space orbiting the Earth, and use them to navigate the globe. Such audacity would only have been found in a Jules Verne novel.
But today, the Global Positioning System (GPS) is a reality, and a working one at that. As of the year 2009, there are now 31 active satellites in the GPS constellation. With all this sophisticated technology up there, you should have no problem finding a signal! GPS systems are definitely here to stay. While these systems were originally deployed for military and commercial shipping and flying use, they've since become the standard for end user consumers to use for navigation as well, even to the point of trivial recreational use, such as with geocaching.
The way that GPS systems can be used for navigation is by triangulating on a signal from space and using the time it takes to receive the signal to determine the distance from the source of that signal. A signal from one satellite isn't very helpful - that could be an infinite number of points around a circle on the face of a globe. The signal from two satellites is somewhat useful, since there's only two points on the surface of a globe which can match the distance from two satellites.
With the exact distance from three visible satellites, you have a theoretically perfect pinpoint location, but such accuracy would require a highly accurate clock - we're talking nanosecond accurate. Thus, four or more satellites are used and the results can be easily averaged out to indicate the location of the received signals. That should help explain why we have so many redundant satellites up there, and remember also that you can't receive a signal which has to be traveling straight through the Earth.
The most typical use of a GPS receiver for private use is automotive navigation systems. These devices interpret the data from satellites and download maps from Internet servers or use built-in mapping software to display the current location of the device, and can easily be clipped to the visor of a car and used like a live, updated map.
Companies which rely on a mobile dispatch model are also increasingly turning to GPS systems for tracking their units. Companies such as mobile repair services and taxicab services use the devices both to dispatch the nearest unit and assist individual drivers with navigation. Police, fire, and paramedic units are dispatched in cities with the assistance of GPS. GPS tracking is even coming into use in package delivery - you just might be able to pinpoint the exact location of your package in the very near future when it's being handled by UPS or FedEx.
A typical GPS system is made up of GPS terminals, some form of mapping data service, and service centers. These systems typically tie together diverse technologies of Internet, mobile terminals and networks, and automotive and consumer electronics such as mobile phones. The market is rapidly developing, and each company has to keep coming up with new innovations and ways of providing their products cheaper in order to stay competitive.
Filed Under: GPS, GIS and Navigation
