Chapter 3 SPAN Operation
OEM7 SPAN Installation and Operation User Manual v14
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been halted by user command, the calibrated offset value can be viewed in either the
INSCALSTATUS
log
or the
INSCONFIG
log.
To save a calibrated rotation for subsequent start ups, issue the
SAVECONFIG
command after calibration is com-
plete. Each time the IMU is re-mounted this calibration should be performed again. See also
page 96 and
on page 96 for details on coarse and kinematic alignment.
After the
INSCALIBRATE RBV ENABLE
command is entered, there are no body-vehicle rotation para-
meters present and a kinematic alignment is NOT possible. Therefore this command should only be
entered after the system has performed either a static or kinematic alignment and has a valid INS solu-
tion.
For information about the logs and commands used in this procedure, refer to the
.
3.4.7 Multi-Line Body to Vehicle Frame Rotation Calibration Routine
The single pass Body to Vehicle frame offset calibration feature assumes flat ground when estimating the roll off-
sets between the IMU Body and Vehicle frames, as this component of the rotational offset is difficult to observe
through typical ground vehicle motion. In practice this can result in an outstanding roll offset error as high as sev-
eral degrees. For applications where vehicle roll must be well known, or pass-to-pass accuracy of a highly offset
position is especially important, the Multi-Line IMU Body to Vehicle frame offset calibration routine offers higher
calibrated accuracy in roll. This is done by running independent calibrations over the same ground path in oppos-
ite directions; averaging the results cancels out the effect of any terrain induced roll. A minimum of two iterations
are required. Additional iteration pairs can be executed for increased reliability.
