Kongsberg EM 2040 MKII, Installation Manual

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154
472405/A
In order to establish a system
to measure the relative
distance between sensors, a
virtual coordinate system is
established. This coordinate
system uses three vectors; X,
Y and Z.
A
The X-axis is the
longitudinal direction
of the vessel, and in
parallel with the deck.
A positive value for X means that a sensor or a reference point is located ahead
of the reference point (origin).
B The Y-axis is the transverse direction of the vessel, and in parallel with the deck.
A positive value for Y means that a sensor or a reference point is located on the
starboard side of the reference point (origin).
C The Z-axis is vertical, and in parallel with the mast. A positive value for Z means
that a sensor or a new reference point is located under the reference point (origin).
D
Reference point (Ship Origin)
Coordinate system origin
The origin is the common reference point where all three axis in the vessel coordinate
system meet. All physical locations of the vessel’s sensors (radar and positioning
system antennas, echo sounder and sonar transducers, motion reference units, etc.) are
referenced to the origin. In most cases, the location of the vessel’s "official" origin
has been defined by the designer or shipyard. This origin is normally identified with a
physical marking, and also shown on the vessel drawings.
Frequently used locations are:
• Aft immediately over the rudder (frame 0)
• Vessel’s centre of gravity
• The physical location of the motion sensor
Coordinate system alternative origins
If necessary, other origin locations may be defined for specific products or purposes. One
example is the
Navigation Reference Point that is frequently used. Whenever a vessel
is surveyed to establish accurate offset information, the surveyor may also establish an
alternative origin location. Whenever relevant, any such alternative locations must be
defined using offset values to the "official" origin established by the designer or shipyard.
A commonly used alternative origin is the physical location of the vessel’s motion sensor.
Defining the physical location of each sensor
By means of the vessel coordinate system, the physical location of every sensor can
be defined using three numerical values for X, Y and Z. These values must define the
KONGSBERG EM 2040 MKII Installation Manual