Compass And Altimeter Calibration - DeLorme Earthmate PN-60 GPS User Manual

Compass and Altimeter Calibration

The PN-60 comes equipped with two sensors; an electronic compass and a barometric altimeter.
• The electronic compass works when the PN-60 is moving at less than 1.5 miles per hour. The compass readings
calculated from GPS information are accurate only when the device is moving.
• The barometric altimeter uses the elevation adjusted to mean sea level and barometric pressure to provide more
accurate elevation readings than the calculated GPS elevation provides.
Changes in weather patterns and geographic locations can cause errors in sensor readings. Calibrating the sensors
ensures that they record and display accurate data on the device and record accurate data in the track file.
The Calibrate option is available from the Satellite Page and the Compass Page, and is under the Compass & Altimeter
option on the Settings Page. In addition, from the Settings > Compass & Altimeter menu, you can enable or disable
the electronic compass, barometric altimeter, and the auto-calibrate barometer options , or restore the default settings.
Compass Calibration
• Calibrate the electronic compass the first time you use the PN-60.
• Make sure you are outside and away from magnetic fields, such as those caused by vehicles and power lines,
when you calibrate the compass.
• Calibrate when you change the batteries. Batteries, even those of the same type, have unique magnetic fields that
affect the accuracy of the electronic compass. The device periodically checks the compass accuracy; if it is poor,
"Poor Accuracy" appears in the bottom right corner of the Compass Page and a red exclamation point displays in
the Heading info field. If the warning does not go away, try calibrating the compass.
To calibrate the compass
1. From the Satellite Page or the Compass Page, go to MENU > Calibrate > Calibrate Compass.
OR
From the Home Page, go to Settings > Compass & Altimeter > Calibrate > Calibrate Compass.
2. Follow the on-screen instructions to calibrate the compass.
Altimeter Calibration
There are three options for calibrating the altimeter. By default, the device is set to auto-calibrate the altimeter using
GPS elevation; however, manual calibration using the known elevation or barometric pressure provides greater
accuracy.
Auto-calibration uses the average GPS elevation as a basis for the barometric elevation. Adjustments are made to take
into account changes over time in the barometric pressure, unrelated to changes in elevation. As the elevation adjusts
(typically in 2-3 minutes), "Calibrating" displays in the bottom right corner of the Satellites Page. If you are using the
Elevation: Barometer info field on any page, it displays a red exclamation point.
Note that the unit settings used in the Known Elevation and Known Pressure fields are from the units set on your
device. To change the units, go to Settings > Units > Pressure.
Earthmate PN-60 User Manual | Compass and Altimeter Calibration 59