Figure 3: Heading Measurement With Gams - Applanix POS MV V5 Installation And Operation Manual

After alignment, the IMU delivers measurements of multibeam transducer heading relative to true north.
These measurements possess the same accuracy as those of vessel heading defined in the paragraph
above.
Refer to the Theory of Operation description on page B-1 for a more complete description of GAMS,
together with an explanation of GNSS carrier phase differential position measurement, levelling,
gyrocompassing and the Kalman Filter.
Refer to the Lever Arm Distances, page 2-26, and the Antenna Baseline Vector
The antenna baseline vector is the vector describing distance from phase centre of primary antenna to
phase centre of secondary antenna in the vessel frame. If this vector can be determined accuractely
(error <= 5 mm) then the values can be entered into the GAMS parameter setup window and avoid
having to perform a GAMS calibration, which on a large vessel may not be practical or as accurate. If the
antenna baseline vector cannot be accurately determined and the vessel can perform dynamics sufficient
to achieve a good GAMS calibration then the baseline vector parameters can be left as zero.
Refer to the Lever Arm Distances, page 2-26, and the Antenna Baseline Vector
The antenna baseline vector is the vector describing distance from phase centre of primary antenna to
phase centre of secondary antenna in the vessel frame. If this vector can be determined accuractely
(error <= 5 mm) then the values can be entered into the GAMS parameter setup window and avoid
Copyright © Applanix Corporation, 2017
POS MV V5 Installation and Operation Guide
POS MV with GAMS
heading aiding
IMU begins levelling
and alignment
Rotation
Levelling
POS MV power-on
& alignment data
After levelling
Kalman
Filter
Ship frame wrt Heading alignment
reference frame
complete within
mounting angles
2 to 5 minutes
Heading
Rotation
information
Vessel heading
Rotation
accuracy = 0.02
degree
(0.03° for
WaveMaster)
Sonar heading
accuracy = 0.02
degree
(0.03° for
WaveMaster)

Figure 3: Heading Measurement with GAMS

IMU wrt reference
frame mounting
angles
GPS derived heading
information
& alignment
Surveyed antenna
Rotation
Heading aiding information in
IMU coordinate frame
Sensor 1 (Sonar) wrt
reference frame
mounting angles
Introduction
GAMS
baseline vector
1-9