Issue link: https://geospatial.trimble.com/en/resources/i/1468600
Inside the Trimble X7: Deep Dive into Trimble X7 Auto-Calibration 10 10 This calibration line has an extremely stable calibrated reference distance and has a built-in Variable Optical Attenuator (VOA), which allows us to modify the pulse signal level. Before each scan is initiated, we measure the distance given by pulses passing through the calibration line for all possible signal levels. The result of such a calibration is shown in figure 7. Figure 7: Distance correction look-up table As we know the physical reference distance of the calibration line we know the distance offset correction that must be applied for a distance measured with a given signal level. Therefore, when we carry out a 3D scan, for each distance measured, we use the pulse signal level to apply a distance correction according to the Look-Up- Table given by figure 7. Thanks to this innovative approach, X7 users can have confidence that every scan in all conditions will give them the quality data that they expect. Smart Calibration The auto-calibration feature is smart and monitors environmental temperature, ambient light, vibration, instrument temperature and vertical speed to optimize the process. Under normal conditions full automatic calibration will take approximately 25 seconds and under the worst conditions like extreme ambient light or vibration from the ground or wind, the process will automatically adapt and cover up to 45 seconds. The system will effectively compensate for the temperature range and after temperature stabilization the calibration time will decrease and may not have to be run at all. The instrument can even adjust to a normal level of shocks and vibration after transportation. Internal and external conditions are continuously monitored and a watch dog will perform a calibration refresh if required to stay within the accuracy range. Smart automatic angular and distance calibrations ensure consistent data quality without the maintenance cost, downtime and hassle associated with annual calibrations. Note: Even though the smart calibration feature can help compensate for shock and vibration, users should take care when handling the instrument. Follow the instructions in the user guide for care and maintenance and good station setup practices.