Tuesday, August 25, 2009

GPS for Off-Road Navigation

The Global Positioning System, generally known as GPS has evolved into an accurate easy to use navigational aid for professionals and casual outdoors persons alike. Consumer GPS devices can be broken into three main categories; general purpose, automobile, and marine. For the purpose of this dissertation I’ll focus on the general purpose GPS, however they all work on the same basic principle; they are simply configured to optimize certain tasks.

In simple terms GPS units tune in to signals being sent from NAVSTAR satellites orbiting 12,000 miles above the surface of the earth. The accuracy of your GPS at any given time and place will vary depending on how many satellites you are tracking. The more satellites you are tracking at a given location the higher the degree of accuracy. The GPS then relates the signals from the satellites you are tracking to a specific position on earth letting you know, often within feet, where you are.

Even low end GPS units contain the basic functions necessary for navigation. They not only tell you where you are at a given time but allow you to save waypoints. A waypoint is simply a specific geographical location. For example you will want to mark your camp as a waypoint and if you are hiking or hunting, you will likely mark the location of your vehicle as a waypoint. You will then periodically mark trail crossings and other points of interest you may pass so you can easily return to them at some time in the future.

A set of waypoints can be saved to create a route, allowing you to follow a specific path over and over again. Or, you can use the “GO TO” function to select a specific waypoint – perhaps your car – that you want to head for. The arrow on your GPS will keep pointing to the waypoint until you reach it. You will also get information like distance traveled, distance to waypoint, and average speed. Even if you need to make a detour around a marsh or lake the arrow on your GPS will always point in the direction of the destination you have selected.

Higher end units give you the ability to download topographical maps, road maps, and charts directly to your GPS unit. You will not only see your location and waypoints but you will see them relative to the map you are using.

I would like to leave you with a word of caution before you head confidently into the wilderness with your new GPS. Sometimes I think GPS technology has become too easy to use, in fact it has become so easy to use that the average outdoors person is now able to get themselves into trouble in half the amount of time. That’s right, don’t use a GPS for wilderness travel unless you know how to use a topographical map and compass, and have them with you.

Here are a few cautions to keep in mind when using a GPS:

1. A GPS does not work, or may give inaccurate readings, under heavy tree cover!
2. A GPS does not always function well in river bottoms surrounded by high hills or cliffs!
3. A GPS can be affected by dense cloud cover and adverse weather conditions!
4. A GPS requires power to work! Loose you batteries and you’ve lost your ability to navigate with a GPS.
5. Use the neck lanyard or wrist strap. Most units don’t float.

The portable GPS has opened opportunities for outdoors lovers that were only dreamed of 15 years ago. I highly recommend that a GPS becomes a part of your outdoor gear, but learn how to use it and never head into the wilderness without a compass and topographical map. Getting lost in Southern Ontario farmland is an inconvenience; getting lost in our huge northern forests can be life threatening.

Keep updated with all your Southern Ontario outdoors activities at http://www.sooutdoors.ca/.

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