GPS Receiver  – Basic Features

A handheld GPS receiver can be a wonderful tool for expanding one’s access to, and enjoyment of, the outdoors. A quality unit, such as a Garmin GPS receiver, or a Magellan GPS receiver, will provide basic functions that can quickly be mastered, so that you may find yourself wondering how you got along without one for so long!

There’s one misconception about GPS receivers that can come up from time to time, that may be helpful to clear up. A GPS navigation receiver does not transmit any kind of signal in any way.

Some worry about their cell phone, since it transmits a signal, being used as a means of pinning down their location by secretive government agencies. This may or may not be a concern for you. As far as your new Lowrance GPS receiver, this will not happen.  As it only receives a signal, sent out by the GPS Sat Nav system, and does not transmit, you won’t be seeing unmarked black helicopters coming over the horizon in your direction while you’re out in the wilds!

The basic features you’ll need in your new GPS receiver are:

It reports your position in latitude and longitude coordinates.

This one is a given, as all consumer GPS receivers do just this. You’ll probably have the option of using UTM (Universal Transverse Mercator) coordinates as well. UTM coordinates are used on USGS topographic maps, and serious hikers will be familiar with this system.

It accepts different “map datums”.

To simplify a somewhat complicated subject, a map datum is basically a model of the basic shape of the globe that the latitude and longitude coordinates are calculated from. If you recall from high school science, the earth is not a perfect sphere, but “bulges” in the middle due to its rotation. If a perfect sphere was used as the model for latitude and longitude, the North Pole would be about 6.5 miles in the air! There have been different map datums used by various countries, at different times in the past. If you plan on using your GPS receiver  extensively outside North America, this will become important to you. If not, there are basically two map datums you need to be concerned with- NAD27 (North American of 1927- used on most USGS topo maps), and WGS84 (World Geodetic Survey of 1984 Another choice which may appear in your GPS receiver is NAD83, which is virtually identical to WGS84). Unless you are using coordinates from a USGS topo map, set your GPS receiver for WGS84.

It stores waypoints.

These will either be coordinates to locations you’ve entered yourself, have downloaded online, or are programmed into the GPS receiver when you buy it.

It calculates direction and distance from your current position to a waypoint.

This is called a “heading”, and will get you where you want to go.

It plots a “breadcrumb trail”, also called a track log, as you move.

This will be useful when you want to map a new trail you are making as you go.

With more expensive GPS receivers it displays full-featured maps.

Most commonly these are topographic maps that display the terrain as you move.

You can also purchase (expensive) GPS receivers that have built in barometric altimeters or magnetic compasses. You would be better off buying these items separately. They will be cheaper on their own, and will not be extra functions to chew up battery power while you’re out in the field.

The author, Mike Wreggitt, is an avid outdoorsman, and has extensive experience in outdoor navigation, much of it prior to the development of GPS technology. To learn more about GPS receivers, GPS navigation, and much more, visit http://GpsForHiking.net.

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