Juniper Systems LandMark Mobile - Manual (Page 41)

LandMark Mobile User’s Manual 41
Display Option Distance Units Speed Units
Feet Feet (changes to miles
at 13,000 ft.)
Miles per hour
Meters Meters (changes to kilo-
meters at 1500 m)
Kilometers per hour
Heading
The Heading option allows you to set the display compass
readings to the following:
True
Auto Mag (automatic magnetic declination)
Manual Mag (manual magnetic declination)
WMM 2K (World Magnetic Model 2005)
Declination is the angle formed between magnetic north and true
north from the GPS receiver’s location.
True
The True selection uses true north as the compass heading.
Auto Mag
The Auto Mag selection displays all compass headings as
magnetic north using the magnetic declination value from the
NMEA RMC packet sent by the GPS satellite. The declination is
applied to the Auto Mag reading and appears on the GPS screen
modified, adjusting for the altered declination degrees.
Note: If the receiver you are using is not able to use RMC or VTG
NMEA packets and the declination does not appear in the Diagnostic
screen, do not use Auto Mag with that receiver.
Manual Mag
The Manual Mag value uses a negative (-) number for East
declination and a positive (+) number for West declination. When
manually entering the declination, use the box to the right of the
Heading drop-down menu and specify either East (using a negative
value) or West (using a positive value).
WMM 2K
Earth’s magnetic field, as measured by a magnetic sensor on or
above the Earth’s surface, is a composite of several magnetic fields
generated by a variety of sources.
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