There are several buttons on the face of most GPS units that, when pressed, route you to various operating options. They may have different names, but they have similar functions. They may allow you to view a navigation screen, status satellite signal availability, review your positions list, or determine your position relative to a selected destination. The following explains what some of these options are:
This screen displays present position, elevation, and time of day. If a destination or route is active, it may also indicate direction toward the destination.
If there is an active destination or route, this screen will point to that location and provide bearing, distance and time to go to get there.
If you are moving, the current heading and speed are displayed. If a destination or route is active, this screen gives bearing and distance to that position. It also provides an indicator if you are on or off course.
This screen provides you access to the different listings of options (like a pull-down menu) available for your computer. Usually you move the cursor over the topic you want, and hit “enter” to see what is available.
This screen provides a track history of the route travelled, and the bearing and distance to the listed destination.
Most GPS units have a feature to display how many satellites it is tracking and what level of satellite signal strength it is receiving. If more than 4 satellites are visible, the receiver will choose the best 4 satellites, based on signal strength and triangulation angle.
Landmark or Waypoint List or Library/ Route List:
You usually can view the positions you have stored in memory so that you can rename or delete them, or plan a route. You can sometimes add icons (a FISH or CAR or TREE, etc), to distinguish important waypoints. Usually, there also is a route option, to review/edit the routes you have made, or to prepare a new route.
Most units allow you to choose units, time system, the coordinate system, map datums, and true or magnetic north. There may also be options to receive Differential GPS signals, or download data.
Distance to (GO TO):
This feature allows you to select a stored position, and make it active. Then it provides the bearing and distance to that location, from where you are.
Cross-Track Error (XTE):
If you have selected a position or waypoint that you wish to travel to, and make it a route or leg, then as you move, the cross-tract error indicator will tell you if you are on the direct line between your start and stop point, or if you are left or right of that path, by 0.1 mile or 20 miles, depending on the scale you choose.
While your GPS unit is turned on, it will continually update its location every second or two. Your unit may regularly store this last fix location in memory every 10-30 minutes, and refer to it when you backtrack your route, or restart your unit. If you are hiking, and turn it on only every half mile, it will remember where you were last time, and easily relocate the GPS satellites again. If you have traveled over 300-500 miles from your last fix, you may have to re-initialize, or re-cold start the unit.
Some GPS units can provide you sunrise and sunset time for a given day at a given position. This can help you plan to maximize activity in available daylight, or just catch a great sunset shot.