You've been hearing about GPS and have decided that you might be interested in buying one for yourself. The first three things you should do are understand what a GPS is and how it works, determine how you will use it, and then determine a budget. There are many choices available but once you have completed these three things you will be prepared to make an educated choice and get the best value to meet your needs.

What is GPS?

The Global Positioning System, better known simply as GPS, is a satellite based navigation system developed by the United States military and made available for civilian use in the 1980's. The overall GPS network is made up of 24 satellites that orbit the earth. Basic GPS receivers can pinpoint any location within a few feet. It is widely expected to become the next personal utility in the same way that cellular phones have over the past couple of decades.

GPS works using the navigational process of triangulation. It can determine your location by using its' relative position to that of two or more of the satellites. The more satellites a GPS receiver can communicate with the more exact a position can be determined - in some cases down to inches.

How will you use your GPS?

GPS work differently and provide different output based on the need they were designed to fulfill. There are specific GPS designed for automobiles, pilots, and others for hikers and/or other outdoorsman. Some will show a map while others will just give longitude and latitude coordinates for someone charting their movement. Within each category there are several choices based on how sophisticated a system you want and how much you are prepared to spend.

If you plan to use you GPS in your car there are several choices available; a system designed specifically for cars, a laptop system or a system that integrates with your PDA. In addition a handheld system can be used but offers much less versatility than the other options. I would not recommend buying a handheld unit for use in your car but if you already have one you may find it helpful in navigating while driving.

If you are planning to use your GPS in your car on a regular basis I would recommend a unit designed just for cars. The advantages are that they have a bigger screen which is easier to see while driving, have voice commands, and will give you turn by turn directions. These advantages make for fewer distractions while driving and, in my opinion, are well worth the extra cost involved. While both laptop and PDA compatible software are available these options may require additional equipment such as external antennas to operate properly and even then you may experience some reception difficulties.

If you are looking for a GPS to use while hiking/backpacking, hunting or fishing, you have several options available. You can use a basic handheld unit, a handheld mapping unit, or a PDA based system. While relying on any of these systems if you are off the beaten path I recommend you take alternative means of navigation with you such as a map and a compass as well as back up batteries for your unit.

With the most basic handheld units you will have to plot your position as obtained from the GPS on your paper maptherefore make sure your map is marked with latitude and longitude coordinates. Systems offering a mapping feature may well be worth the extra cost to many, but remember because they offer more functionality they are slightly heavier. For the fisherman there are also systems that include depth sounders and chart plotters in addition to the basic functionality.

Depending on your requirements, systems range in cost from around $100 for the most basic handheld unit to several thousand dollars for the more sophisticated systems.