# covariance matrix for odometry using encoder

Hi,

I have two wheel encoder and I'm able to calculate the distance and publish it as a nav_msg/odometry. I don't know how to calculate the covariance matrix for the same.

I publish the following:

Pose: x,y and orientation (but basically yaw) Twist: vel x (as my robot is non-holonomic) and angular rate z.

Can someone please help me solve this? Is there a formula to calculate the covariance?

Thanks & Regards Sriram

This is probably a better question for the Robotics Stack Exchange.

Hi Tom,

Thanks I'll post the question there. I have another issue. If possible could you have a look at it. find odom_combined