GPS		COMPUSA'S TOP SELLERS
Garmin Nuvi 205W GPS Portable and affordable, Nüvi 205W GPS is your personal travel assistant for life on the go. Its priced right and ultra-easy to use. Only $139.99	Magellan Roadmate 1200 GPS Designed for simple, efficient and reliable vehicle navigation, the affordable Magellan RoadMate 1200 offers full navigation function. Only $79.99	1.  Magellan RoadMate 1412 GPS N 2.  Garmin Nuvi 255 GPS (Refurbi 3.  Magellan Maestro 5310 GPS ( 4.  Magellan Roadmate 1400 GPS 5.  Garmin Nuvi 205W GPS 6.  Garmin Nuvi 265WT 4.3" GPS B 7.  Garmin Nuvi 750 Auto GPS - R 8.  Magellan RoadMate 1430 GPS ( 9.  Garmin Nuvi 755T GPS 10.  Magellan 4350 4.3" GPS (Ref Also Available: Overstock - GPS

Garmin - Nuvi 200 - GPS Navigation (Refurbished) Garmin - Nuvi 200 - GPS Navigation With 3.5-Inch LCD Touch Screen (Refurbished) Only $99.99    Garmin Nuvi 255 GPS (Refurbished) Garmin Nuvi 255 GPS - 3.5" Touch Screen, HotFix, Picture Viewer, 3D Map View, North American Maps (Refurbished) Only $99.99    Magellan RoadMate 1430 GPS (Refurbished) Magellan RoadMate 1430 GPS - 4.3" Wide Touchscreen, Text to Speech, US And Canada Maps, MSN (Refurbished) Only $99.99    Magellan Roadmate 1400 GPS Magellan Roadmate 1400 GPS - 4.3" Touch Screen Display, 1.3 Million POI, Pre-Loaded Maps For Continental US/Hawaii/Puerto Rico Only $109.99    Magellan RoadMate 1412 GPS Navigation Magellan RoadMate 1412 GPS Navigation - 4.3" Touch Screen Display, Text-To-Speech, US/Hawaii/Puerto Rico/Canada Maps Only $119.99    Navigon 2100 Max GPS Navigation Navigon 2100 Max GPS Navigation - 4.3" Touch Screen Display, Text-To-Speech, POI, Predictive Text, Free Lifetime Traffic Alerts Only $119.99    Magellan RoadMate 1430 GPS Magellan RoadMate 1430 GPS - 4.3" Wide Touchscreen, Text to Speech, US and Canada Maps, 3 Months Free Traffic Alerts Only $129.99    Garmin Nuvi 750 Auto GPS - Refurb Garmin Nuvi 750 Automotive GPS - 4.3" Touch Screen, MP3 Player, North American Maps (Refurbished) Only $145.99    Tom Tom GO 630 GPS Tom Tom GO 630 GPS - 4.3" Widescreen, Text to Speech, US Maps (Including Puerto Rico) and Canada, 2GB Internal Flash Memory, SD Card Slot, RDS-TMC Traffic Compatible, (Refurbished) Only $149.99    Garmin Nuvi 255W GPS Garmin Nuvi 255W GPS - 4.3" Touch Screen Display, 3D Map View, SD Card Slot, HotFix, North American Maps Included Only $159.99    Garmin Nuvi 780 Auto GPS Garmin Nuvi 780 Auto GPS - 4.3" Touch Screen Display, Text-To-Speech, Bluetooth, MSN Direct, MIllions Of POI, North American Maps Only $209.99    Garmin Nuvi 265WT 4.3" GPS Bluetooth, TTS, Traffic Garmin Nuvi 265WT GPS - 4.3" Touch Screen, Text To Speech, Bluetooth, North American Maps Only $209.99    Garmin Nuvi 850 GPS Garmin Nuvi 850 GPS - 4.3" Touch Screen Display, 3D Map View, microSD Slot, North American Maps Only $249.99    Magellan Maestro 5310 GPS (Refurbished) Magellan Maestro 5310 GPS - 5.0" Touch Screen, North American Maps, Text-to-Speech, Ultra Thin Design (Refurbished) Only $129.99    Spot Satellite GPS Messenger Spot-1 Tracker Spot Satellite GPS Messenger Spot-1 Tracker Only $149.99    Garmin Nuvi 755T GPS Garmin Nuvi 755T GPS - 4.3" Touch Screen Display, Text To Speech, 3D Buildings, SD Card Slot, North American Maps Only $229.99

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Global Positioning System – GPS

At the end of the 1970s, the United States Department of Defense (DoD) conceived a Global Positioning System (GPS), which allowed any element of the military (planes, ships, submarines, tanks, ground forces) to know their position – via the technique of trilateration – precisely and instantaneously, anytime and anywhere on the Earth's surface. The Global Positioning System (GPS) was built to fulfill this task.

In essence, the GPS system is made of a constellation of satellites constantly orbiting the Earth, at an average altitude of 20,000 kms, scattered on six equally spaced orbital planes. As a result, at least three satellites are always visible at any time from any place on the Earth’s surface. Each satellite emits a coded signal containing essential GPS Navigation/GPS Location information, such as its position and the exact timing of the signal emission to Earth. Therefore, only a simple receiver is needed to measure the elapsed time between emission and reception of the signal. The satellite to station distance is deduced from this travel time.

By way of trilateration, three different measurements made on three different satellites provide the three distances needed to determine the three coordinates of the station (GPS systems) position (the location of the receiver): latitude, longitude, and altitude. This type of measurement is known as "pseudo-range" measurement in GPS jargon. Every satellite emits two types of pseudo-ranges: A precise code (P code), which enables a position precision of around 10 meters, and a coarse code (C/A code), which allows a precision of around 100 meters. The precise code is encrypted and restricted to the U.S. military receivers. Civilian applications are based on the pseudo-ranges measurements of the C/A code. Even using the C/A, incredibly precise location positions are still possible for everyday use.

GPS Navigation Systems

There are three main types of GPS devices available for consumer and commercial use: GPS Navigation, GPS Tracking and GPS Location.

GPS Navigation (such as Garmin GPS or Magellan GPS Navigation Systems) is used to help you locate where YOU are right now, and get you from Point A to Point B. There are numerous devices made for GPS Navigation. From hand-held units equipped with a digital compass to navigators that are installed in cars and commercial vehicles, by manufacturers such as Garmin, Magellan, TomTom, Navigon, Sony and more. These are basically mapping systems, which are used as a Personal Navigation Device. Each has very limited recording (tracking) capability and generally do not have the ability to create and upload detailed logs of vehicle travel, though they do often include a digital compass and a chart for general navigation.

Several businesses have already invested in mapping systems to increase productivity by improving route planning. Personal navigation devices, which can be used for geotagging, are also becoming widespread. In conjunction with a digital camera, geotagging allows you to mark the precise location of where your pictures were taken. As for the navigational system itself, it usually comes with a mounting bracket, and provides easy placement onto your dashboard. Once the mounting bracket is firmly secured onto your dashboard and the GPS navigator is turned on, you are then guided to your destination, usually via text-to-speech and voice instructions from the touch screen. Voice instructions allow you to keep your eyes on the road during your trip, while the GPS remains safely secured on the dash.

The navigational system, which is often times Bluetooth-enabled, also provides several Points of Interest throughout your trip, as well as alternative routes to avoid traffic. You can select your Point of Interest via the touch screen. Many are traffic-ready navigators and can detect a congested road up ahead as well. Additionally, you can get a GPS receiver to use with your Bluetooth-enabled portable computer, as well as a software mapping system to provide GPS mapping right on your personal computer, from makers like Deluo and Microsoft.

Used in the automotive industry, GPS Tracking records a log of all vehicle (or personal) activity and travel over an extended period of time. These devices are usually hidden under the dash. GPS Tracking is useful in eliminating time-consuming and poor quality automotive use logs; as well as increase productivity, and accountability, by maximizing business use of your vehicles, while decreasing or eliminating personal use. They are also great to keep track of where kids have been driving to. The best units provide second-by-second tracking for the highest accuracy of position AND speed traveled, while built-in motion sensors only collect data during actual travel, thus allowing for a much longer recording period.

To pin-point the current exact location of your device, GPS Location is used to provide Real-Time positioning of a vehicle or the GPS device, so you know where it is right now. These usually provide minimal tracking capability or none at all, and are not a replacement for GPS Tracking. GPS Location is mostly used for fleet vehicles, emergency location positioning or as an aid in recovery of a vehicle or asset. GPS Location includes a chart and involves "Pinging" the device via satellite or by cell phone, and having it "phone" home with its current position via satellite cellular technology. Therefore, there is a recurring cost for GPS Location that does not usually apply to GPS Tracking.