Garmin GPS 3 Manual

Notice the information on the map display is slowly moving? That’s how it would
look in actual use as well. The background map information and nearby waypoints
will move across the screen, while your current position remains fixed in the center.
The other primary navigation screens are the Compass and Highway pages, with
the Compass Page appearing first in the sequence of main pages. 
To view the Compass Page, press PAGE.
The GPS III’s Compass Page provides graphic steering guidance to a destination...

To view the Highway Page, press PAGE.
The Highway Page provides a graphic highway display that shows your move-
ment relative to the desired course. The line down the middle of the highway repre-
sents your desired course. As you navigate toward your destination, the highway will
actually move, indicating the direction you’re off course. To stay on course, simply
steer toward the center of the highway. As you approach the waypoint, the highway
will end at the final destination. When the waypoint marker...

The GPS III’s Satellite Status Page provides a visual reference of various receiver
functions, including current satellite coverage, receiver operating mode, battery level
and position accuracy. As the receiver locks onto satellites, a signal strength bar will
appear for each satellite in view, with the appropriate satellite number (01-32) under-
neath each bar. The progress of satellite acquisition is shown in three stages:
• No signal strength bars— the receiver is looking for the satellites...

You can use the sky view to help determine if any satellites are being blocked,
and whether you have a current position fix (indicated by a ‘2D Navigation’ or ‘3D
Navigation’ in the status field). You can also set the sky view to a ‘Track Up’ config-
uration, causing the top of the sky view to align along your current track heading.
When the receiver is looking for a particular satellite, the corresponding signal
strength bar will be blank and the sky view indicator will not be highlighted. Once
the...

Poor GPS Coverage— the receiver isn’t tracking enough satellites for a 2D or 3D
fix due to bad satellite geometry.
Not Usable— the receiver is unusable, possibly due to incorrect initialization or
abnormal satellite conditions. Turn the unit off and back on to reset, and reinitial-
ize the receiver if necessary.
Simulating Nav— the receiver is in simulator mode.
‘Need to Select Initialization’ Prompt
If no satellites are received for several minutes (or an insufficient number of satel-
lites are received...

EPE and DOP
The Satellite Status Page also indicates the accuracy of the position fix, using
Estimated Position Error (EPE) and Dilution of Precision (DOP) figures. DOP mea-
sures satellite geometry quality (i.e., number of satellites received and where they are
relative to each other) on a scale from one to ten. The lowest numbers are the best
accuracy and the highest numbers are the worst. EPE uses DOP and other factors to
calculate a horizontal position error, in feet or meters.
Screen Backlighting...

The following Satellite Status Page options are available:
Start Simulator— allows you to activate the GPS III’s built-in simulator mode. If 
‘Start Simulator’ is selected, ‘Stop Simulator’ will appear as an option instead.
To activate (deactivate) simulator mode:
1. Highlight ‘Start Simulator’ (or ‘Stop Simulator’) and press ENTER.
2. Highlight ‘Yes’ and press ENTER.
Track Up— changes the sky view display from ‘North Up’ orientation to align to 
current direction of travel (track). If ‘Track Up’ is...

With 2D coverage, you will
need to enter your approxi-
mate altitude. Without an
approximate altitude, your
position error can be substan-
tial.
The Position Page shows you
where you are, what direction
you’re heading and how fast
you’re going.
30
REFERENCE
Set 2D Altitude— allows you to designate your approximate altitude, when the 
GPS III is acquiring satellites or navigating in 2D mode. By default, 2D naviga-
tion will attempt to use the last known altitude. If the altitude shown is off by 
several...

Many features of the GPS III are menu driven. Each of the main pages has an
options menu, allowing you to custom tailor the corresponding page to your prefer-
ences and/or select special features which specifically relate to that page.
To display the Position Page Options, press MENU (with the Position
Page displayed).
The following options are available:
Average Position— allows you to average position samples over time and save the 
averaged result as a waypoint. Averaging reduces the effects of...

Change Fields— allows you to choose the data displayed on the six user-selec-
table data fields. Available data types are: Altitude, Average (Avg) Speed, Battery 
(Bat) Timer, Max Speed, Odometer, Speed, Sunrise (at present position), Sunset 
(at present position), Track, Trip Odometer, Trip Timer, User Timer and Voltage. 
See page 85 for descriptions of navigation terms.
To change a data field:
1. Highlight ‘Change Fields’ and press ENTER.
2. Highlight the data field you wish to change (using the rocker...