The Global Positioning System is a location positioning system consisting of a network of 27 earth-orbiting satellites. These satellites are solar-powered and circle the Earth at approximately 12,000 miles an hour. Traveling around the globe twice every 24 hours at anytime during the day there are at least four satellites located within the sky anywhere on Earth. This network was developed by the United States military and they implemented the network of satellites as a military navigation system. The tremendous commercial potential of this new satellite network system was soon realized and it was opened up to the public.  It changed the face of navigation as we know it.

When someone refers to a GPS they are usually referring to a GPS receiver. A GPS receiver is the device that you carry with you or put in your car to display your location on a map or relative to other objects.  It receives signals from the GPS satellite network to determine its present location. The GPS receiver works by locating the satellites in the GPS satellite network and then using their location relative to it to establish its own location through a process known as trilateration.

A personal navigation assistant is similar to an automotive navigation system but is designed to work as a hand-held device and is not focused on car-related travel. While many automotive GPS units are designed to be mounted inside the vehicle the hand-held GPS units are more portable and can be easily carried around. Since the late 2000’s, many large mobile phone companies have begun to incorporate GPS receivers into mobile phones and completely integrating the personal navigation assistant into the phone. With advances in technology it is predicted that GPS assistants will be rapidly integrated into mobile phones within the next few years.

When it comes to GPS navigation software, the types of software available can typically be divided into two categories:

Tracking software uses the GPS to track the position of the device relative to the satellite network and displays it on the device with an electronic map background image. This type of software allows for routes to be pre-programmed and shows the user where they have been.  This gives them a line or similar visual route indicator to follow on the screen.

Route calculation software provides the user with directions calculated and then given to the user by the software.  Often this is achieved with a vocal interface. It is the most popular form of GPS software used for automotive navigation systems and uses a vector-based map for calculations.

Navigation software makes use of tracks, routes and waypoints in order to calculate specific travel routes and travel times. Tracks are traces of where the user has been with the device.  At times, tracks can also be manually inputted. Points are recorded onto the device when the unit collects and sends details of its current location.  It is then noted by the software. Devices can be programmed to make points at specific time intervals and each point is stored on the device along with its time and date. Putting the traveling points together in chronological order results in a track which traces the user’s traveling route. Tracks can be used to retrace steps if you should get lost.

Tracks can also be indicated when traveling pre-planned routes.  They are especially helpful when a user travels off the indicated route. The device can then display both the route and the track.  It assists the user in becoming oriented.

Another important part of software route planning is the waypoint. Waypoints are used by the GPS software to mark particular locations on maps and are used as markers along the journey. Waypoints can differ from device to device, map to map and place to place. They can be inputted by users as custom identified places, sights or locations, or can be downloaded from official sources to serve as guiding landmarks when traveling. Waypoints can also be used for safety purposes, marking route obstacles such as cliffs or landslides or other hazards that could obstruct the route.

A number of navigation software products are available for use on computers provided they either have a built in GPs receiver or a portable receiver that can attach to the computer. The majority of commercial software is only available for the Windows or MAC OS X operating systems.  However, with the popularity of GPS usage rising, projects (some of which are open-source based) have begun development in order to make GPS software available to other computer operating systems. Using devices such as a Smartphone or a PDA is usually preferable for day-to-day GPS.  Routes can be planned and then uploaded or downloaded from the Smartphone or PDA. These devices are also useful to travelers and tourists as they can assist in tracking travel routes and making accurate travelogues.