By Josh Brandt and David Bitner
Winter 1997

The Garmin GPS 45 is a small pocket sized GPS unit that allows for quick readings in the field of position in latitude and longitude. Other functions allow you to store points that you can then either recall later for data interpretation or to find your way back to the area using the bearing distance page. The GPS can be used to gather data to use for ground truth or to correlate images to map datum for a GIS.

The first step in using the GPS is to turn it on and acquire the satellites which it needs to gather fairly reliable data. When you press the on button (the red light bulb) the first screen that you get to is the satellite status page which shows which satellites are coming in and at what strength. Before a 3-d fix can be made four satellites need to come in fairly strong. It is important that you are away from any buildings so that the unit can have a clear line to as much of the sky down towards the horizon as possible. When the unit has picked up enough satellites to make a reading from it will then turn to the position page which will display position, altitude, speed, bearing, and time. To get to the other functions of the GPS press the page button. First you will come to a page which will show a map of where you have gone, then a page which will show you how to get to a prestored point. One more press of the page button will get you to the menu which will help you personalize the system as well as get to the advanced functions of the unit.

To move through the menu, it is a matter of using the arrows and the enter key. The quit button will always take you to the previous level of the menu. The first things which you may want to check are the setup functions. The operation setup allows you to tell the unit how many hours you are away from Greenwich, set the contrast, and tell the unit to stop beeping. The Navigation setup allows you to change the map datum, the position format, and the units.

To use the waypoint features simply press the mark button when you are on a point that you wish to save and then use the arrow keys to store a name for that point pressing enter when done. Once you have assigned a name to the spot you can then just use the goto button and, upon entering the name for the point, the unit will tell you which way that you need to go to get to the point (this works best if you keep moving rather than standing still). Under the menu you can find the nearest waypoints to where you are or just a general list of all waypoints currently stored.

Overall, the Garmin GPS 45 is a very easy to use menu driven system which if you need to find something you can just peak into a few menus and quickly find what you need. The only tricky part left is how to turn the unit off. To do this just hold down the red lightbulb button for three seconds.