Sentinel V SC and RT Operation Manual
September
2017
EAR-Controlled Technology Subject to Restrictions Contained on the Cover Page.
Page 119
Troubleshooting a Low Calibration Score
If the calibration score is low:
Remember, a score of 10/10/10 is not required to pass the compass calibration. A score of 8 or 9 in any of
the three fields is sufficient to get accurate compass headings.
If the Standard Deviation score is 7 or lower, there may be several factors contributing to this problem:
•
Nearby sources of dynamic interference – computer monitors, test equipment, etc., that can gen-
erate time-varying magnetic interference in the environment.
•
Nearby sources of static interference – hard and soft iron in the nearby shelving, rebar, steel,
iron, magnets, changing magnetic fields, etc.
•
Moving the compass in space between points in the calibration can cause the Standard Devia-
tion score to get worse when calibrating in a magnetically noisy environment. Make sure that
the compass module is the center of rotation for the instrument in all the various orientations to
substantially lower the standard deviation score.
•
Remove phones and metal objects from pockets.
•
When in doubt, calibrate outside and away from metal, machines, and electronics.
If the X-Y coverage score is 7 or lower, make sure the rotation directions and tilts are followed. The
compass calibrations procedures use
40
degrees tilt for steps 1 through 4 and
65
degrees for steps 5
through 12 during calibration is desired. Over-tilting can also lower this score.
If the Z coverage score is 7 or lower, it usually means the system was not being tilted enough during cali-
bration (a score of 1 means the system was not tilted at all).
Restore to Factory Defaults
If the compass calibration fails after repeated attempts, use the Restore to factory defaults button.
This will use the factory calibration of the compass module itself as it was shipped from the vendor, not a
system level calibration at the time of manufacture at TRDI. This calibration will not take into considera-
tion variables such as magnetic fields from batteries or mounting fixtures. The assumption is a factory cal-
ibration may be better than a failed field calibration result.
