Kongsberg Seapath 320, Installation Manual, Page: 65 / 152

Installation Manual
M300-62/rev.2 49
A typical alignment process
consists of aligning the MRU
axes to an external reference.
Type of reference must be
determined according to the
required accuracy.
The reference for roll and
pitch alignment must be
carefully selected depending
on the intended application. It
may be the hull, a sensor such
as a multibeam echo sounder
or a USBL acoustic system.
Some sensors have internal
alignment routines, and
accurate alignment of the
MRU is not required. The
MRU mounting wizard is
described later in this manual.
This includes an automatic
procedure for obtaining the
roll and pitch mounting
angles.
Figure 21 Alignment of MRU yaw axis to vessel
longitudinal axis
An accurate alignment of the MRU +R arrow towards the vessel's longitudinal axis
(yaw orientation) is of special importance. If not properly aligned, the performance of
the roll and pitch measurements from the MRU will be degraded. Figure
22 illustrates
that a misalignment of 1 degree of the MRU in yaw will result in a roll error of ±0.09
degrees if the vessel is pitching ±5 degrees. To calculate the misalignment of the MRU
axis to an accuracy of 0.5 degrees or better is not an easy task and requires use of an
accurate external reference.