Issue link: https://geospatial.trimble.com/en/resources/i/1468600
Inside the Trimble X7: Deep Dive into Trimble X7 Auto-Calibration 8 8 Collimation Modes The internal collimator is used in two different modes to perform the automatic calibration. ▪ Auto collimation mode - internal collimator camera measures the center unit mirror to the front and back side for the trunnion axis error. ▪ Collimation mode – internal collimator camera measures EDM shots over the vertical deflection angle for horizontal & vertical collimation errors. Internal Collimator Measurements and Calculations Measuring horizontal and vertical collimation errors of the sighting axis is an automatic process of positioning the vertical telescope movements so that the laser sighting axis points directly into the nadir. The laser spot will be identified with the internal collimator camera in the base unit and will be measured with the center of gravity. Keeping the vertical position as it is, the instrument will turn a full circle horizontally measuring permanently the spot position on the camera chip. The given figure of the spot will be exactly a circle with a center representing the vertical axis. At least two measurements are required for constant horizontal angle and different vertical directions. Both points are defining a line. The foot dropped perpendicular from the circle center will be calculated. The deviation equates to vertical collimation error. The distance between circle center and the foot print defines the blind spot or the sum of the instrument trunnion axis error "k" and horizontal collimation error "c". In case the trunnion error is known the horizontal collimation error can be calculated. Figure 4: Internal Collimator Measurements and Calculations