Your source for GPS info in everyday terms

    
Home · Pitfalls

GPS devices are wonderfully capable but also complicated for the new user. GPS Primer provides GPS info explained in simple, everyday terms to get you started on the right foot in your travels.

GPS Info Articles

RSS Feeds

GPS Pitfalls

There are a few things to keep in mind when using a GPS that may not be obvious to a beginner. Read through these to keep the surprises to a minimum.

A Moment of Privacy, Please
Every time you turn your GPS on, it will need some time to track down the satellites. The longer you have had your GPS off, the longer it will take. It can be a few seconds if you've only had your GPS off a few hours, to 20 minutes or more, depending on conditions, if you have had your GPS off for months. This is normal, just give it time--and a clear view of the sky.

Blue Skies, Smiling at Me
Your GPS needs a clear view of the sky to find the satellites. It will not work in a building, nor too close to buildings or hills that block the horizon. Handheld GPS units can be problematic in a car (see below). And even heavy leaf cover can interfere. If your GPS unit is having trouble finding satellites, step out into the open. If in doubt, find a clear view of the southern horizon in the northern hemisphere, as the satellite tracks favor the middle of the globe rather than the poles.

Basic GPS units are Poor Compasses
Basic GPS's do not have internal compasses. They have a hard time determining what direction you are facing when you are standing still. They calculate your direction using the GPS satellites, and you must be moving for the GPS to figure out which direction you are facing. If you want your GPS to function more like a traditional compass, where you stand still and orient yourself to a certain direction before moving, make sure the model specifies that it has an internal compass. These are usually more expensive models. Or, just bring a regular compass with you; they are cheap!

Not THAT Accurate
GPS receivers' maximum accuracy is 10 feet under ideal conditions. Much of the time it will be less accurate than that, 50 feet or worse, and fluctuates as you move. This is still plenty accurate for most uses most of the time, but it can be a little disconcerting at first. WAAS-enabled units are supposedly more acccurate more of the time, but are still at the mercy of satellite visibility and atmospheric conditions.

Got Batteries?
GPS receivers need batteries to function. Always bring spares...and bring an old fashioned compass and paper map if you will be in unfamiliar territory.

Baby, You Can Almost Drive My Car...
Handheld GPS units don't do well in cars. They don't see well through the metal and glass of the car. You may need an external antenna. Navigational GPS units built for cars will include this...but then they aren't designed for walking.

Wilderness Safety
With a GPS, you might find yourself more likely than you ever were to explore somewhere you have never been, or even get off the trail as you hunt for a geocache. Do some research on wilderness safety before you head out. Always tell someone where you are going and when you expect to be back. Bring water and emergency supplies, especially foul weather gear, even if you are only going to be out for the afternoon. Remember you can go without food for days, but hypothermia or heat stroke can kill you in hours--and dehydration makes hypothermia (or heat stroke) more likely.

Maps, Maps, Maps
You still need maps. You can store a lot of information in your GPS, but good old maps will still be useful. Drive to the park using roadmaps, use the trail maps to get into the general area of your destination, then use the GPS to zero in.

Mother May I
Always respect the rights of landowners, be they your neighbors or the government. Obey the rules concerning trespassing, restricted areas or sensitive wildlife habitats. Check the park regulations concerning journeying off the trail.

Keep Your Feathers Numbered
Always have a back up plan in case your GPS fails. You may run out of batteries, drop the unit in a lake, or just can't get a good fix on enough satellites due to weather or landscape, or delete a waypoint by accident. If you will be in unfamiliar territory, bring a paper map and a compass "just in case" you need to find your way back out without your GPS.