C Commands Summary
108 MiLLennium GPSCard SW Version 4.503/4.52 Command Descriptions Manual Rev 2
MAGVAR
The GPSCard computes directions referenced to True North. Use this command (magnetic variation correction) if
you intend to navigate in agreement with magnetic compass bearings. The correction value entered here will cause
the "bearing" field of the NAVA/B and GPVTG logs to report bearing in degrees Magnetic. The magnetic variation
correction is also reported in the GPRMC log. The GPSCard will compute the magnetic variation correction if you
use the auto option.
Syntax:
Example:
magvar +15.0
MAGVAR correction [std_dev]
OR
MAGVAR auto
Syntax Range Value Description Default
MAGVAR -Command
correction ± 0 - 180 The magnetic variation correction for the area of navigation in units of degrees.
Magnetic bearing = True bearing + Magnetic Variation Correction
See Figure C-3.
0.0
std_dev ± 0 - 180 Option: the estimated accuracy of the magnetic correction entered (in degrees).
This option is currently not applicable to this product.
auto The GPSCard calculates values of magnetic variation for given values of latitude,
longitude and time using the International Geomagnetic Reference Field (IGRF)
95 spherical harmonic coefficients, and IGRF time corrections to the harmonic
coefficients.