NavX Reading Z?

[rclothier]

Our NavX board reads X and Y velocity and displacement just fine, but returns only zeroes for Z velocity and displacement. Any suggestions? Is the Z velocity just too low to register when you are driving uphill?

[slibert]

Originally Posted by rclothier

Our NavX board reads X and Y velocity and displacement just fine, but returns only zeroes for Z velocity and displacement. Any suggestions? Is the Z velocity just too low to register when you are driving uphill?

Yes, as you surmised the Z velocity information (derived from the Z-axis accelerometer data) is not anywhere near realistic. In the Z-axis, the accelerometer data is dominated by the earth's gravity, and that combined with the noise in the accelerometer data means that when the acceleration data is integrated oveer time, the compounded error results in a velocity term very unreliable for use in velocity estimation.

[rclothier]

Fair enough. Thanks for the explanation.