POS MV V4 User Guide
Introduction
Copyright © Applanix Corporation, 2009
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GNSS Azimuth Measurement Subsystem
GNSS Azimuth Measurement Subsystem (GAMS) is a unique feature of POS
MV that allows the system to achieve exceptional accuracy in the
measurement of heading. The GAMS subsystem uses two GNSS receivers
and antennas to determine a GNSS-based heading that is accurate to ±0.02°
(±0.03° for WaveMaster) or better (using a two-metre [~6 ½ feet] antenna
baseline) when blended with the inertial navigation solution. POS MV uses
this heading information as aiding data together with the position, velocity and
raw observations information supplied by the primary GNSS receiver.
GAMS provides heading aiding to the POS MV. To understand the effect that
GAMS has on the system it is useful to compare system performance with
and without GAMS, see
Table 1.
Note: Operation without GAMS will occur when POS MV has insufficient data
to compute a heading solution.
Before POS MV can deliver valid measurements for use in your application,
you must configure the system with the relative mounting angles between the
IMU, the vessel, and the multi-beam transducer. You do this by selecting a
convenient and fixed reference point on the vessel, and by defining a
reference frame orientation centred on that point.
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