Lost About GPS? Here's Some Direction!

By Keith Thompson

If you've been confounded by all the technical jargon and
hype surrounding GPS, confusing what's turning out to be a
very useful tool, allow me to shed a little light on your
roadmap to deciding whether or not this technology is for
you! Originally designed with military applications in mind,
the technology was made available to mere mortals in hte
1980's for the many and varied uses we've found so far for
these special tools. Not only handy for auto navigation, GPS
units have made their way into maritime navigation,
backcountry uses, and much, much more!

How does GPS work? GPS (which stands for Global Positioning
System) allows you to pinpoint your position anywhere on the
planet to within an average of 15 meters, with some units
doing much better than that. Twenty-four GPS satellites,
paid for and placed in orbit by the Dept. of Defense
courtesy of your tax dollars, send signals back to terra
firma 24/7. These signals are retrieved by your handy dandy
GPS receiver which uses three sources (satellites) to
triangulate this information and compute your actual
position. If there are four data sources, even altitude can
be determined. Since there are normally eight satellites in
line of sight from anywhere on earth, the opportunity for
accurate positioning exists. Other things that can be
determined besides latitude, longitude, and altitude would
include things like speed, sunrises and sunsets, bearing,
distance and more. While they will work in any weather, some
hindrances would be electronic interference, buildings, and
certain terrain. A good rule of thumb is that the units will
generally not perform underwater, indoors, or underground.
There are currently two Global Navigation Satellite Systems
in use. Besides GPS, there is the Russian Global Navigation
Satellite System (GLONASS) Protocols are constantly being
refined to enhance the abilities of these systems. A bright
light on the horizon is Galileo, scheduled to go online in
2008, which promises even greater accuracy and
functionality.

So how do I know which GPS unit is for me? Quite a few
choices now exist for consumers in the GPS marketplace.
Whether you need a handheld unit for backpacking or boating,
or one for your automobile (they are becoming an attractive
option!) or for one of a myriad of uses, there are several
reputable manufacturers of quality GPS units out there to
help you find your way through the maze of choices. Names
like Magellan, Garmin, Rino, Etrex and Meridian lead the
market, and are readily available. Take your time, check out
the various features each has to offer, and get yourself
outfitted with one of the more useful and efficient
navigational tools out there today!