Estimated acceleration

Most engine logs have no accelerometer. BigData estimates longitudinal acceleration from the speed channels the log does have and adds a set of calculated channels: acceleration in G and in other units, an estimated chassis speed, wheel slip, whether the wheels are spinning, and a confidence figure. They carry the ≈ badge and behave like any other channel.

The ⚙ on the channel row opens them:

• Speed source: Auto, GPS, vehicle speed, wheel-speed fusion, or any speed channel it found.
• Filtering: Auto, Fast (50 ms), Normal (150 ms), Smooth (250 ms) or Very smooth (500 ms).
• Wheel spin correction: Off, Auto or Aggressive.

Underneath, read-only lines tell you which chassis speed was used, the window actually applied, the sample rate and resolution of the source, and anything it decided not to use. Changing a setting recalculates immediately.

It was validated against logs that also carried a real accelerometer and it tracks well on clean pulls. It is still an estimate from wheel speed, so anything that makes wheel speed lie degrades it: spin, a tyre size change, or a speed channel that updates slowly. The confidence channel and the resolution line are there to tell you when that is happening.