The Global Positioning System offers consumers access to a network of satellites that can provide pinpoint navigational information in real time. GPS devices use signals from these satellites to triangulate your position anywhere on the globe, correlating that data with internal maps or other information to provide your position accurately. Depending on your needs, there are a number of different types of GPS devices available.
One of the most common forms of GPS receiver is the automotive GPS unit. These units contain a GPS receiver as well as an internal road map database, providing you with a real-time view of the surrounding streets as you drive. They also typically include a navigation feature that allows you to set a destination and receive turn-by-turn instructions as you travel. More advanced units may provide real-time traffic information or include a cellular modem for weather updates, business searches or other features. Aeronautical or maritime GPS units offer similar functionality for air or watercraft.
Another common form of GPS is the hand-held, outdoor GPS unit. These devices are popular with hikers and outdoor enthusiasts, as they can prevent you from getting lost even in the roughest terrain. Outdoor GPS units typically include terrain maps and the ability to plant virtual flags, giving you a quick route back to places you have already been. These GPS units are also popular with geocaching enthusiasts, a hobby involving the planting of “treasure” caches that users visit, taking and leaving items to mark their passage.
You can also use GPS devices to track people or items. Unlike consumer GPS navigators, these devices usually lack a display, containing only a GPS receiver and some sort of communication relay, usually a radio antenna. The tracker periodically updates its location using the GPS system and transmits that information over the communication link, allowing you to track the subject in real time. GPS trackers used as part of a security system may also include a feature that allows the device to set off an alarm if it passes beyond a set boundary, allowing you instant notice if a tagged item or person leaves a secured area.
GPS devices can also enhance emergency beacons and other equipment used on ships and aircraft. These devices commonly include maps and navigational features similar to outdoor GPS but may also include a radio or satellite link for communication or signaling. One-way signal devices are most common due to the expense of satellite communication, but some advanced units may even include a satellite radio for two-way communication. In some cases, the GPS tracker and communication device is automatic, activating when passengers deploy emergency equipment or the device detects a crash or other vehicular problem. These devices can greatly increase the response time of emergency personnel to plane crashes and other dangerous situations, giving victims of these accidents a greater chance at survival.
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