POS MV V4 User Guide
Installation
Copyright © Applanix Corporation, 2009
2-4
auxiliary GNSS antenna. For a DGNSS or P-Code receiver used as an
auxiliary unit, make these measurements to an accuracy of ±0.1 m (~±4 in).
For an RTK receiver used as an auxiliary unit, make these measurements to
the same accuracy as the Reference to Primary GNSS Lever Arm to prevent
a bias in the position output by POS.
• A positive value for the X lever arm means the auxiliary GNSS
antenna is forward of your reference point
• A positive value for the Y lever arm means the auxiliary GNSS
antenna is to starboard of your reference point
• A negative value for the Z lever arm means the auxiliary GNSS
antenna is above your reference point
Note: If your application does not include an auxiliary GNSS receiver, record
these lever arm distances as zero.
Reference to Centre of Rotation
Normal dynamics in a marine environment apply a complex combination of
forces to a survey vessel, causing the vessel to experience a continuously
varying pattern of heave, roll and pitch.
Under the influence of these, vertical movements experienced by the multi-
beam transducer include two components:
• Heave movements as the vessel moves vertically in the water - in the
absence of any changes in vessel attitude, these will be the same
throughout the vessel.
• Apparent heave movements under the influence of roll and pitch - the
amplitude of these will vary directly with distance from the vessel
centre of rotation.
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