Calculating amcl robot specific error parameters

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Hi everyone, I am implementing navigation stack on our robot. Unfortunately, the odometry from wheel encoders is not accurate and because of this the amcl is not working fine as we expected. Could anyone have idea how to calculate odometry noises i.e., odom_alpha1 to odom_alpha4 on physical robot which are parameters for amcl. I have gone through Probabilistic Robotics book but nothing was mentioned there and trying to calibrate the robot using UMBmark test and not sure how to incorporate the values. It would be great if someone has idea regrading this. Thank you.