Chapter 3 SPAN Operation
OEM7 SPAN Installation and Operation User Manual v14
80
The X, Y and Z axes of the IMU Body frame are typically indicated on the IMU enclosure.
The X, Y and Z axes of the IMU Body frame are also indicated on the mechanical drawings of the IMUs
in the
Figure 24: IMU to Antenna Translation Offset
below shows an example of the translational offsets from the IMU
to a GNSS antenna. In this example, the IMU Body Frame (indicated by the small arrows) has the Y axis point-
ing in the direction of the vehicle motion and the z axis pointing up.
Figure 24: IMU to Antenna Translation Offset
If the distances measured in this example were X Offset = 1.000 m, Y Offset = 1.500 m and Z Offset = 2.000 m,
the following values would be entered, based on the IMU Body Frame:
l
x = -1.000
l
y = -1.500
l
z = 2.000
The translational offsets are entered using the
SETINSTRANSLATION
command. For this example, the com-
mand to enter these offsets is:
SETINSTRANSLATION ANT1 -1 -1.5 2
The measurements for the translational offsets should be done as accurately as possible, preferably to
within millimeters especially for RTK operation. Any error in the offsets will translate into an error in the
INS position.
The translational offsets from the IMU to the GNSS antenna are required for all SPAN systems. However, some
SPAN systems may have other sensors or devices integrated into the system for which the SPAN needs trans-
lational offsets. For example, a gimbal mount or a camera or LiDAR connected to an Event Input line. The off-
sets to these additional sensors and devices are also entered using the
SETINSTRANSLATION
command.
By default, the translational offsets are entered in the IMU Body Frame. However, in some systems the IMU
Body Frame may not be known precisely. For these cases, the
SETINSTRANSLATION
command has an
