GPS Buying Guide From Overstock
The Global Positioning System was created by the US Department of Defense to answer the second most important question an army has: “Where are we?” Today, GPS satellites orbit the Earth, constantly sending signals ground-ward; these signals can be picked up by a GPS receiver which then calculates the user’s position on the Earth’s surface. It didn’t take long for civilian agencies–police, fire, ambulances and construction crews–to see the value in GPS systems and begin using GPS tracking systems.
Consumer applications soon followed, though the electronics industry needed to refine the GPS tracking system into a profitable consumer electronic line. After all, it does you little good to know that you’re at 40 degrees 33 minutes 24 seconds north 118 degrees 48 minutes 36 seconds west, unless you already know that’s where Overstock.com is located and you’re trying to parachute onto the office roof. Consumer electronics added street by street visual directions to create a user-friendly GPS navigation system.
GPS buying tips
Before buying a GPS unit, first consider how it will be used:
* Car GPS is probably the most popular application. Auto GPS units include street maps; high-end models even offer turn-by-turn voice instructions. Frills include touch screen operation, cell phone connectivity, video games, radio, CD or DVD players and computer links to receive GPS system updates.
* Cell phone GPS was mandated in the aftermath of September 11th, 2001. The US Federal Communication Commission (FCC) required cell service providers to make GPS tracking of cell phone calls possible. All phones made since 2005 are GPS-equipped. Cell phones including handheld GPS receivers are also available but may not operate properly if you are outside your cell providers’ service area.
* Recreational GPS includes wrist or armband and handheld GPS units. The wristwatch-size model portable GPS units are especially good for hikers and bikers. Larger portable GPS units are designed for carrying in the pocket or backpack or mounting on the dashboard.
* Marine GPS systems are, of course, waterproof (most consumer electronics don’t react well to water!) and they float–not a feature you actually want to use, but extremely valuable should extreme circumstances arise. Ocean maps are notoriously dull to read, but shoreline maps and features like tide tables and fish-finders can be very useful. Marine GPS tracking is especially valuable when entering or exiting crowded harbors.
Second, determine how much to spend on your GPS navigator. Prices range widely, depending on features. A basic GPS unit, one that only displays latitude and longitude, is good for hiking if you have a map and some basic map reading skills (what is life in the great outdoors if you always take the great indoors with you?). Fancier handheld GPS units display coordinates over a map; map quality and level of detail vary. Car GPS systems range from a simple dash-mount GPS navigation system to multi-component in-dash car audio system with all the bells and whistles.
Third, visit Overstock.com, where your GPS buying dollar will go farther, regardless of what model or features you choose.
GPS components
The Global Position System consists of three parts:
* Satellites: Twenty-four active plus five standby satellites orbit the Earth twice each day. At least four should be ‘visible’ to the ground at all times, allowing GPS tracking system users to precisely determine latitude, longitude and altitude.
* Command and control system: Currently under the direction of the US Air Force Space Command, certain segments are managed by other agencies, such as the US Coast Guard Navigation Center (for maritime issues).
* GPS receivers: Civil and military GPS units are receive-only electronics; they do not transmit data or interact with the rest of the GPS system. This allows an unlimited number of simultaneous users. In other words, this may be the only operation of the US government that is available 24/7 and will never put you on hold!
Accessories and add-ons are available to enhance GPS navigation unit use:
* Maps: Most GPS units have factory installed street maps of the United States. World travelers can purchase additional GPS system maps of Canada and other areas.
* Data storage: GPS users can store even more if the device supports removable memory cards–like those commonly used for digital cameras.
* Combo packs: For most people, GPS receivers work great on their own. For the serious user/traveler, portable GPS devices are available with personal digital assistants (PDAs) and two-way radios built in. As noted, car GPS devices can include all sorts of entertainment or media extras.
* GPS holders: These attach to the car dashboard or console so your handheld GPS doesn’t have to be handheld while driving.
* GPS antennas: These amplify GPS signals and are especially useful in urban areas where there is more chance of interference from terrestrial sources.
* GPS chargers: Obviously, a handheld GPS must be recharged; at home and car adapters are available.
* New stuff: GPS systems are an emerging technology, their full scope not yet known. Check the Overstock.com GPS page regularly to see what new models and accessories have been added.
GPS terminology
Nationwide Differential Global Positioning System
A US Department of Transportation program operated jointly with the Commerce and Homeland Security departments. Using fixed land-based reference stations, civilian GPS accuracy can increase to just 1-3 meters (less than 10 feet). Commercial GPS receivers are almost always on target to within 15 meters (about 49 feet) but many users see accuracy levels within 5 to 10 meters (just over 30 feet).
Geocaching
Geocaching (pronounced /GE-oh-CASH-ing/) is a new and exciting game gaining popularity every year. Simply put, it’s GPS hide-n-seek; gamers place objects ranging in size from a 35-mm film can to a military ammo box in plain sight. The locations (latitude and longitude) are logged onto web sites. Players use their GPS units to locate the caches, called ‘waypoints‘. It’s a whole lot harder than it sounds. Waypoints can be disguised as plants or rocks and getting within 10 meters still leaves a lot of ground to cover. Some waypoints are pick-n-place, meaning they have prizes inside; when you find one, trade a trinket you’ve brought for the trinket you have found.
Benchmarks
One of the early means of determining locations was small metal markers placed by the US National Geodetic Survey (NGS). These are still in place and are found all over the US on street corners, mountain tops, in parks and other obvious and not so obvious places. All benchmark locations are logged and available from the NGS. They make a quick and easy way to see if your GPS unit is working properly or for geocaching.
GPS care
Like all modern consumer electronics, a GPS receiver has few moving parts to break, so it can provide years of service if not abused. Dust, heat, humidity and impact damage are primary causes of failure. Don’t drop your GPS unit, not even onto something soft like water–especially not onto something soft like water!
Wipe it down with a clean cloth before you put it away and, if your GPS receiver has openings like a data card slot or battery compartment, blow those clean with canned air–never your humid breath.
If you own a car GPS system, mount it out of direct sunlight. Even on cool days, the dashboard can get dangerously hot for a GPS system and excessive exposure to the sun’s radiation can damage the memory–yes, sunburn can be terminal for a GPS terminal.
Back to the top Common GPS questions.
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