Specifications

BATS AND PORTABLE BATS OPERATION
3-54
Hydrophone X and Y offsets are entered with respect to the pitch / roll center of the vessel. It is
assumed that the vertical reference for the pitch / roll center is the water-line of the vessel or the
entered “DEPTH OFFSET”. Once the X and Y Offsets are entered and the dialog box closed, a small
"Hydrophone" symbol appears in the Plotting Window and moves in relation to the X and Y offsets
that are input. This "Hydrophone" symbol represents the actual position of the hydrophone. The
ships reference point remains in the center of the tracking display.
NOTE: The Trackman software outputs the target position with respect to the pitch / roll
center of the vessel graphically in the Display, numerically in the Status Block and
also on the RS-232 serial communications port.
NOTE: The X and Y coordinates of the USBL Hydrophone are different from the X and Y MRU
coordinates of the EdgeTech Motion Sensor Unit (Model 4760B). The Z axis polarity
is also different. (The Hydrophone Z Offset is always positive below the water surface
while the MRU Offet below the water surace is negative.) Refer to MRU Manual for
entering offsets into the MRU.
Depth Offset: Manually enter the depth offset as determined in section 2.4.2. This is the Depth of
the hydrophone from the water surface (which is assumed to be on the same plane as the pitch/roll
center of the vessel) to the tip of the hydrophone. Manual mode only. Auto Offset is used only in
special cases.
Attitude Offset: This is the (static) vertical offset of the hydrophone in degrees.
Enter the hydrophone attitude error corrections in degrees. It is used to offset the static attitude of
the hydrophone/staff. The attitude (pitch/roll) offsets are error constants that compensate for the
non-vertical installation of the hydrophone shaft and/or vessel trim. The operator must measure
the angle of the shaft with respect to vertical and enter the data in this menu. Pitch and roll errors
are entered in degrees. Maximum range is +/- 45°.
The attitude (pitch/roll) offset errors follow the polarity convention of; vessel Bow up = [+], Port
up = [+]. For example, if the combined hydrophone shaft and vessel trim causes the Hydrophone
(4610B or 4211A) mounted on the end of the staff) to tilt towards the port side (has the same af-
fect as tilting so that the port side of the vessel is up), the roll error is entered as a positive value.
And, if the Hydrophone is tilted towards the aft of the vessel (vessel attitude = bow down) the
pitch error is entered as a negative value. Also, refer to section 2.4.3.
Pitch and Roll have also been referred to as Tip (fore/aft) and Tilt (port/starboard).
Units: Sets the units that the dimensional offsets are relative to; Meters, feet or Yards.
Orientation: If an EdgeTech remote Pitch and Roll sensor is used, such as the Model 4730A,
4740A or 4760B-V the system can allow for different mounting configurations of these VRU assem-
blies. In some instances, when attempting to mount the VRU assembly as close to the pitch and
roll center of the vessel as possible, a convenient (bow facing) mounting surface is not always
available. The software can compensate for four different mounting arrangements. The VRU ORI-
ENTATION function allows a VRU assembly to be mounted in the NORMAL position with the assem-
bly's directional arrow facing towards the bow, or mounted to STARBOARD, AFT or PORT.