Navigation Using GPS Devices

GPS is an acronym standing for Global Positioning System. Though there are lots of components, the essential parts are a series of satellites and the units people carry. Three satellites are used to locate your position across the Earth’s surface and another can be used with them to calculate your altitude in a process called triangulation.

GPS units come in an array of prices, with the higher priced models offering more features. A very basic unit will have a display and controls that allow you to find your latitude (east-west lines drawn around the Earth) and longitude (north-south lines radiating from the North Pole to the South Pole).

Within that basic configuration there are a variety of models and styles, most of them from Garmin. Garmin is the leading manufacturer, but there are others. Whichever brand you favor, you’ll find options for different battery life, control placement and weight.

Some models are waterproof – very handy when crossing rivers and lakes or if you get caught in a storm. Different models offer different numbers of waypoints. A ‘waypoint’ is another term for terrestrial coordinates – latitude, longitude, altitude, etc. (‘etc’ because there are, in fact, several ways to locate a point in space other than latitude, longitude and altitude.)

Another use of the term ‘waypoint’, and one which is incorporated into different GPS units, is the number of landmarks given on the display. That will vary depending on which map is loaded, but the ability to display more can be a blessing or a curse. You need enough to orient yourself, but the screen can become too busy to be useful.

As you go up in price, most GPS units will add features like a digital compass. Other options can include the ability to download area maps into the unit, or changing maps, zoom and relocate, and many more.

One popular Garmin model (the eTrex) is waterproof, displays up to 500 waypoints, and features controls along the side in order to maximize the display size. It’s also lightweight (150g with batteries.)

Prices range from $100-$300 or more. In the GPS arena you often get what you pay for. The Garmin eTrex Summit, for example, is around $200 and has some handy features. Some GPS units require movement in order to give a heading, but the built-in compass of this model allows you to stand still and get a reading.

It also has an altimeter for judging height. That’s very useful when you are trying to use the GPS in conjunction with an area map and the contour lines showing altitude are confusing. Like other models, it has 12 channels. Those extra channels – just like a portable home phone – give you options when you might get interference from other nearby devices.

Different models have some nice-to-have features like back-lighting so you can read them at night without holding a flashlight. Many offer a tracking log so you can recall where you’ve been. That’s very useful for drawing on a paper map to nail down your route.

Do some research and look at a lot of models before deciding. If you do, you’ll definitely find one that suits your needs and budget.

Leave a Reply

You must be logged in to post a comment.