Fix typo

[ricber]

Apart from that little typo It's a little confusing how do you set the covariance matrix diagonal. I suppose the 0.02 number comes from the fact that the standard unit of measure for length is meter so 2cm = 0.02m. But then you assign the same variance to roll, pitch, yaw that are measured in radian. Could you clarify this point? Thanks.

[methylDragon]

I actually just assigned an arbitrary value for the yaw, pitch, and roll for convenience. They stuck because I didn't see any major issues with those particular dimensions (to be honest, since I was navigating in 2D, only yaw mattered.)

Kalman filter covariance tuning is a pretty tricky business, and while there are probably computational or algorithmic ways to tune them, I find that it's mostly about being able to feel the right way to tune things... You'll have to try things out and see the result, then tune accordingly. I recommended using rosbag to ensure consistency of data at the bottom of the first part of the tutorial.

Thanks for the typo fix though!