Feature Guide: Surface Tilt

Overview

The Surface Tilt feature allows you to redefine the reference plane for roll and pitch measurements from your OXTS device.

Normally, roll and pitch are measured relative to a plane normal to gravity. The Surface Tilt function instead enables you to define a flat reference plane aligned with the surface on which your vehicle operates — for example, a test track or proving ground.

This feature is particularly useful when the ground surface is not perfectly level, ensuring that your roll and pitch measurements reflect vehicle motion relative to the actual driving surface rather than to gravity.

Before Beginning

Accurate surface tilt measurement depends on stable motion and correct setup of the device. Before starting:

• Ensure Stable Mounting: The device must be firmly mounted with known lever arms.

• Perform a Warm-up Run: Always complete an INS warm-up to ensure the RT is fully initialised.

• Use the Improve Configuration function in NAVconfig to optimise the device configuration.

• Minimise Vehicle Suspension Effects:

  • Preferably use a survey trolley to perform the measurement.

  • If using a vehicle, drive slowly and steadily at a constant speed.

  • Recommended maximum speed: 3 m/s (≈ 7 mph / 10 km/h)

Configuring Surface Tilt

The Surface Tilt tool is accessed and run through a utility in NAVdisplay.

Step 1 — Open the Surface Tilt Tool

1. Open NAVdisplay and connect to your OXTS device.

2. Go to Utilities → Quick Config.

3. Navigate to the Surface Tilt page.

Step 2 — Select Motion Direction

From the Surface Tilt window:

• Choose either Clockwise or Anti-clockwise circle depending on your test area and turning space.

• Click Start to begin the test.

Step 3 — Perform the Measurement

1. Drive in a Circle - drive at a steady, low speed (below 3 m/s) to complete a full circular path.

   • The first half of the circle is used to establish constant motion. This section is shown on the map as a thin line.

   • The remaining circle is recorded and used to calculate the surface plane. The driven path will be displayed as plotted points on the map

2. Once the circle is complete, click Next > to continue.

Step 5 — Applying Results

1. Review the calculated tilt values shown — these are the offsets applied to align roll and pitch with the surface.

2. Tick the checkbox to correct surface roll and pitch using these measurements.

3. Use the options in at the bottom to choose whether to:

   • Apply temporarily — valid until the device is powered off or reset.

   • Commit to configuration — stores the surface tilt correction permanently for future use.

Verifying Surface Tilt Operation

Once the surface tilt has been applied:

• Return to NAVdisplay and monitor Roll and Pitch values.

• Confirm that when stationary on the same surface, Roll ≈ 0° and Pitch ≈ 0°, indicating that the new surface plane is correctly aligned.

• If values appear offset or unstable, repeat the surface tilt procedure at a consistent speed and ensure suspension movement is minimal.