IMU tilt survey style settings

When using a receiver with a built-in IMU, you can configure the survey style to use IMU tilt compensation and, if required, to use the GNSS eBubble when using GNSS‑only mode.

IMU tilt compensation is available only in an RTK survey style. In a postprocessed survey style, select the Tilt functions check box to enable use of the GNSS eBubble when measuring points and to make the Tilt warnings and Auto‑measure options available in the appropriate point style settings.

  1. Tap and select Settings / Survey styles / Rover options.
  2. In the Survey type field, select RTK.
  3. In the Antenna group box, select your model of receiver in the Type field.
  4. In the Tilt group box:

    1. Select the IMU tilt compensation check box to enable "always on" tilt compensation using the internal IMU sensors while roving, navigating, or when measuring points using any measurement method except observed control point.

      To disable IMU tilt compensation and switch to using GNSS-only mode during a survey, for example when using a bipod in heavy canopy and the receiver needs to remain stationary for a period, tap the receiver icon in the status bar and then tap the IMU tilt compensation button in the GNSS functions screen. In good RTK environments where movement is happening constantly, tap IMU tilt compensation to re-enable it.

    2. Select the eBubble functions check box to enable use of the GNSS eBubble when using GNSS-only mode such as when measuring an observed control point, or when the IMU is not aligned or IMU tilt compensation is disabled.

      The GNSS eBubble uses the receiver’s accelerometers and operates independently of the IMU sensors. The GNSS eBubble is only shown when in GNSS-only mode.

    3. Tap Accept.
  5. To configure point measurement settings:
    1. In the survey style screen, select the point type.
    2. Set the Auto tolerance switch to Yes to enable the software to calculate horizontal and vertical precision tolerances that meet the GNSS receiver's RTK specifications for the baseline length and tilt you are measuring. To enter your own precision tolerances, set the Auto tolerance switch to No and then enter the required Horizontal tolerance and Vertical tolerance.

    3. If the eBubble functions check box is enabled in the Rover options screen of the survey style, select the Tilt warnings check box to display warning messages if the antenna tilts more than the threshold value entered in the Tilt tolerance field. You can specify a different Tilt tolerance value for each measurement type.

    4. To enable automatic measurement of points when the required conditions are met, select the Auto‑measure check box. Required conditions depend on the survey mode, for example in RTK+IMU mode the pole tip must be stationary, and in GNSS-only mode the pole must be within tilt tolerance.

      The Auto‑measure check box is not available for observed control points.

    5. To automatically abandon points when the position is compromised, such as where excess movement is detected during the measurement process, select the Auto abandon check box.

    6. Tap Accept.
  6. Tap Store.