To calibrate the sensors in the receiver

Trimble recommends calibrating the tilt sensor and the magnetometer in the R10/R12 receiver:

  • Each time you replace the battery.
  • If the GNSS receiver suffers severe abuse such as a pole drop.
  • If the temperature inside the receiver is more than 30° Celsius different to when the tilt sensor calibration was performed. This high temperature invalidates the tilt sensor calibration, which in turn invalidates the magnetometer alignment.

  1. Because the calibration time is stored in the receiver, make sure the controller has the correct time and timezone.

    The receiver does not need to be tracking satellites to calibrate the tilt sensor.

  2. Open the GNSS eBubble options screen. For example, tap the Settings icon in the top left corner of the eBubble window.
  3. Tap Calib. The Sensor calibration screen appears.
  1. In the Sensor calibration screen, tap Calibrate beside Tilt calibration status.

  2. Level the instrument against a properly calibrated physical bubble and make sure the pole the GNSS receiver is on is as vertical and as stable as possible. In practice this means using at least a bipod to hold the pole as still as possible.

  3. Tap Start.

    When calibration is complete, the software returns to the Sensor calibration screen.

    Because calibrating the tilt sensor invalidates the magnetometer alignment, you must recalibrate the magnetometer alignment after calibrating the tilt sensor.

  4. Tap Calibrate beside Magnetometer alignment status.
  5. Tap Start. Rotate the receiver slowly and smoothly around its vertical axis until calibration is complete.

  6. Tap Accept.

    The details of the calibration are stored in the job. To review them, tap and select Job data / Review job.

    If you tap Cancel before the calibration is complete the previous calibration is lost and the eBubble will not be calibrated.

Take great care when calibrating the tilt sensor to ensure the most accurate tilt information is available at all times.

  • Bubble reference: Calibrate the tilt sensor against a properly calibrated physical bubble. The accuracy of the tilt sensor depends totally on the accuracy of the physical bubble used to calibrate it.
  • Pole stability: When calibrating the tilt sensor, the pole the GNSS receiver is on should be as vertical and as stable as possible. In practice this means using at least a bipod to hold the pole as still as possible.
  • Pole straightness: A bent pole will affect the tilt measured by the sensors in the GNSS receiver. If you calibrate the eBubble using a bent pole and then change poles, the accuracy of points will be affected. Also, if you calibrate using a straight pole and then change to a bent pole, the GNSS will not be plumb even though the eBubble will say it is, again affecting the accuracy of the measured points.

The performance of the magnetometer is affected by nearby metal objects (for example, vehicles or heavy machinery) or objects that generate magnetic fields (for example, high voltage overhead or underground power lines). Always calibrate the magnetometer away from sources of magnetic disturbance. In practice this usually means outdoors. (Calibrating the magnetometer near sources of magnetic disturbance does not "correct" for the interference caused by these objects.)

  1. In the Sensor calibration screen, tap Calibrate beside Magnetometer calibration status.
  2. Detach the receiver from the pole.
  3. Tap Start. Rotate the receiver as shown on‑screen for a minimum of 12 different orientations, until calibration is complete.
  4. Reattach the receiver to the pole. Use the eBubble to make sure the pole is as vertical as possible.
  5. Tap Calibrate beside Magnetometer alignment status.
  6. Tap Start. Rotate the receiver slowly and smoothly around its vertical axis until calibration is complete.

  7. Tap Accept.

    The details of the calibration are stored in the job. To review them, tap and select Job data / Review job

    If you tap Cancel before the calibration is complete, the existing calibration is used.