Tilt calibration

This topic applies to Trimble receivers that have built-in tilt sensors.

Trimble receivers with built-in tilt sensors calculate the degree of tilt of the receiver. The sensors enable you to make sure the pole is vertical and stable and the receiver is level or within tilt tolerance.

Tilt calibration aligns the tilt sensors in the receiver to the physical spirit level vial on the pole, so that when the receiver is level with the vial on the pole, the tilt sensors in the receiver are also level.

The tilt calibration routine takes 30 seconds to complete. You must perform the GNSS eBubble calibration:

  • The first time you use the receiver.

  • When the previous calibration expires.
  • After completing a pole bias adjustment.
  • If the GNSS receiver suffers severe shock such as a pole drop.
  • If the temperature inside the receiver is more than 30° Celsius different to when the eBubble calibration was last performed, the calibration is invalidated.

Take great care when calibrating the eBubble to make sure the most accurate tilt information is available at all times, including:

  • Bubble reference: Calibrate the GNSS eBubble against a properly calibrated reference, such as the physical vial.The accuracy of the eBubble depends totally on the accuracy of the reference used to calibrate it.
  • Pole stability: When calibrating the GNSS eBubble, 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: The straightness of the pole affects the tilt measured by the sensors in the GNSS receiver. If you change poles, and the poles are not both in excellent condition, you should recalibrate the GNSS eBubble. When using an R12i, you should perform a pole bias adjustment after changing poles and then recalibrate the GNSS eBubble.

  1. Set up the receiver so that the pole the GNSS receiver is on is as vertical and as stable as possible, and the receiver has a clear view of the sky.

  2. Make sure the receiver LED panel is facing you.
  3. Tap and select Calibration. Tap Tilt calibration. Read the text on the next screen and tap Next.
  4. Use the vial on the pole to make sure the pole is vertical. Hold the pole still and stable.
  5. Tap START.

  6. Keep the pole stable and vertical until the progress bar completes.

  7. Once complete, tap Done.