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.
This GPS buying guide includes some basic information to help you understand the technology, wade through the options and pick what will best meet your needs.
Before buying a GPS unit, first consider how it will be used:
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.
The Global Position System consists of three parts:
Accessories and add-ons are available to enhance GPS navigation unit use:
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.
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.
Can the government really track me through my cell phone?
Not only the government, GPS tracking via cell phone is a commercial service available for parents (to keep tabs on their children), business owners (to track delivery vans and employees) and others--even pet owners can hook a GPS receiver to their pets, in case Rover lives up to his name. Safety, quality of service and fraud prevention have been recognized by courts as legitimate use of GPS tracking systems for surveillance by non-government entities. GPS tracking abuse and misuse are inevitable, but that is true of every modern convenience and new technology is always followed by new law. If we want the positives of the GPS system, we must live with a few negatives as well. (The day your son, daughter or $100,000 load of someone else's property goes missing, you definitely won't be screaming "Invasion of privacy!" at the FCC.)
Solar flares used to interfere with my satellite dish, do they interfere with GPS?
They will, on occasion. The sun radiates many types of energy, including radio waves. Normal levels are known and GPS satellites are designed to cope with this interference. However, unusually strong emissions can interfere with GPS navigation signals. This is one of those "we can't deal with every problem and keep it affordable" situations.
If "Where are we" is the second most important question, what is the most important question an army has to answer?
Much debate has centered on this topic over the years. Strategists say "Where is the enemy?" is most important, while the more practical-minded argue the most important question an army asks is "Where is the chow line?" GPS systems have not yet been developed that are able to answer these questions, but research continues.
Digital Cameras and Camcorders
Wherever you go, whatever you do, your GPS navigation system will help you get there. Once you have arrived, take pictures! When buying a digital camera, camcorder or GPS, remember that some models use the same type of memory card. This could be an important factor when considering which model to buy. Photos are a great way to remember and share your vacation experiences and Overstock.com has a wide selection of discount digital cameras and camcorders at prices that are so low, you can buy something fantastic and still fill up the gas tank when you're done.
Cell Phones
If your car breaks down on the highway, knowing where you are is useless if you can't tell anyone. GPS tracking your teens' movements is so much more effective when you can call them up and tell them that where they are is where they should not be. Some people are so taken with their cell phones that they've given up "land lines." For the rest of you, a cell phone is not just a luxury; it is a valuable tool that makes life easier, especially in situations when you need to stay in touch