Undoubtedly, one of the best new pieces of technology introduced in the past few years is the GPS system. This has been a boon for wayward drivers who were constantly lost. Instead of having to stop and ask directions, a computer generated map will point out the fastest way to get there. For men — who are never lost, a navigation system is akin to a free gift. Imagine never having to plan a trip again. No more phone calls to the auto club, or getting out the road atlas. Just get into the car and head for that family vacation.

What is GPS?
GPS, or global positioning system uses a bank of 24 satellites orbiting high above the earth. They were originally sent into orbit by the U.S. department of defense strictly for use by the military. However, since being cleared for civilian use, manufacturers have found need applications for consumers. Some of the many advantages include the ability to work in any weather conditions, 24 hours a day, no matter what location on the earth. There are also no subscription fees, only the initial charge for the receiving unit. This device can be installed in the automobile or can be hand-held. It really doesn’t matter what style that you prefer.

How does GPS work?
The satellites in the GPS orbit, circle the earth 2 times each day. An individual with this type of receiver always has at least 4 of them in view at any one time. This is necessary to calculate his/her location on the planet. The signal is measured by the time it takes to reach the satellite and return. Using this data and the relative relationship to any of 3 to 4 satellites, the technology uses triangulation to pinpoint a users exact longitude and latitude. This information is then displayed on the electronic map. Other items of information can then be detailed, including speed, distance to target and current bearing.

How accurate is a GPS unit?
GPS units are remarkably accurate, the older units have a range within 15 meters, while the newer technology is less than 3 meters. The latest innovation is WAAS or Wide Area Augmentation System. Used by the U.S. Coast Guard, this employs the use of beacon transmitters to make slight corrections to the signal. It doesn’t matter what the locale is, or whether there are tall buildings in the area. The unit is able to locate and maintain contact with the orbiting satellites when first powered on. This makes establishing a location fast and easy.

The GPS satellite system
Most “green” power advocates will be happy to learn that all of these satellites are powered by solar energy. Orbiting twice a day around the globe at a speed of 7,000 miles per hour, each of the 24 units maintains it path about 12,000 miles from the earth. Small corrections are made to the course using on board rockets. This ensures that a constant, predictable flight will occur.

The GPS signal explained
This system uses 2 sets of signals, with the one designated L1 for civilian use. This is a relatively low powered radio beam in the UHF range. It’s frequency is 1575.42 MHz, meaning that straight line travel is possible. However, it is not strong enough to pass through solid objects, such as tall buildings or dense shrubbery. That is the main reason for the use of triangulation, or using 3 satellites to fix a location. There are 3 codes embedded into the signal, each being used for a different purpose. The pseudorandom code indicates what satellite is transmitting data. Ephemeris data shows the satellite status, current data and time. The almanac data updates the receiver about where the satellites should be during the day.

The final word about GPS
This is a marvelous piece of technology. By using hardware already present, companies have been able to construct a most useful tool for wayward drivers. Not only does it give directions, but can navigate around road construction and locate others businesses that may be needed. Being now available in a portable format, this eliminates the need for other bulky devices. It is truly a can’t do without personal gadget.