
April
2018
Pathfinder DVL Guide
Page 30
EAR-Controlled Technology Subject to Restrictions Contained on the Cover Page.
The M (mast) axis points in a direction that is closer to upward than downward (mast is always in the
same direction no matter if looking down or up).
Figure 18.
Pathfinder Ship Coordinates (OEM Transducer Shown)
The importance of the ship axis is that the attitude angles (pitch, roll, and heading) measure the orienta-
tion of the ship axes relative to the earth axes, regardless of up/down orientation. The sense of internal
sensors Tilt 1 (pitch) and Tilt 2 (roll) is positive for counterclockwise tilts respectively about the S and F
axes, using the right-hand rule (see Figure 19). One can use the Ship Frame and the alignment commands
to align the DVL Ship axis with the vehicle/platform Ship axis. See
Mechanical Integration Considera-
for more information, and see the
commands. In addition if Tilts are fed to the DVL then
the DVL Ship Frame is then Level.
Figure 19.
Pathfinder Pitch and Roll
Sign of Angle for a Unit Facing
Up
Down
Tilt 1 (Pitch) Beam 3 higher than Beam 4
+
+
Tilt 2 (Roll) Beam 2 higher than Beam 1
+
-