GPS navigationby Tom Jones
This article is intended for people who have never used any form of GPS navigation and is not intended to endorse a particular method or brand.
What is GPS?GPS stands for Global Positionning Satellite. Using some of a number of satellites orbiting the Earth from a fixed distance of 22,500 miles, signals are transmitted to receivers on the ground or in a vehicle. Comparing the relative times the signals from different satellites take to reach Earth, a GPS receiver is able to calculate its exact position.
What is GPS navigation?GPS navigation uses the calculated position information and displays it on a screen along with a map. Software allows the map to be customized and allows for the creation of routes. The net result is that the user sees where they are in relation to surrounding landscape, roads, etc.
GPS navigation comes in three basic forms:
- A stand-alone unit that has a built-in antenna to receive the signals from the satellites, a GPS receiver to process the signals and store the charting software and maps, and a screen on which you can view the maps. One advantage of this type of GPS is that it can be easily moved between vehicles.
There is a wide variety of GPS chartplotters on the market. Handheld units are popular with hikers, while dash-mounted units with larger screens display more information and are more convenient to use while driving.
- Software that you can install on a computer, using the computer to store and display the maps. This method requires an external GPS antenna/receiver to receive the signals from the satellites and compute actual position. One advantage of this method is the larger screen offered by a computer, but it's not very convenient for using while driving.
- A complete GPS system built into the dash of a car. We won't be discussing this version here, but suffice to say it eliminates the need for either a standalone unit or a computer, although typically it cannot be easily removed from the vehicle.
Updating mapsMaps change, roads are diverted and new roads built, so it's important to periodically update the maps. This can be done in one or more of several ways, depending on the manufacturer:
- Download from the manufacturer's web site.
- CDs or DVDs supplied by the GPSmanufacturer.