POS MV V5 Installation and Operation Guide
Installation
2-28
Reference to Sensor 2 Lever Arm
Measure and record the distance from your reference point to the second sensor.
•
A positive value for the X lever arm means the second sensor is forward of your reference point
•
A positive value for the Y lever arm means the second sensor is to starboard of your reference
point
•
A positive value for the Z lever arm means the second sensor is below your reference point
Note
: If your application does not use a second sensor, record these lever arm distances as zero.
Reference to Auxiliary GNSS Lever Arm
The auxiliary GNSS supplies DGNSS, P-Code or RTK measurements to POS MV. Measure and record
the distance from your reference point to the auxiliary GNSS antenna.
•
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 multibeam 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.
The vessel centre of rotation is a point of the vessel that experiences only rotations with changes in
attitude. Any heave measured at this point arises entirely from vertical movements that affect the whole
vessel equally.