Inside the Trimble X7: Deep Dive into Trimble X7 Auto-Calibration 5
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Figure 3: Typical Error Curves from Scanners
Figure 3 shows a diagram of this misalignment effect between the EDM laser and the rotation axis. Data following
sine and cosine distributions is typical of this effect. The curve can be calibrated with the internal collimator and
the vertical drive inside the alidade. In the field this self-calibration can be completed by taking a few spot
measurements at different vertical angles, gathering enough data to create the characteristic spread to fall within
the accuracy range.
Automatic Angular Calibration
The angular calibration is done with the X-Drive dual vertical deflection system which calibrates the angular
accuracy of the rotating mirror by using the servo system and the auto-collimator. A correction is applied to the
collimation error, i.e., the deviation of the Horizontal Axis, or Vertical Axis, or Sight Axis.
