[reversed_rocker]

thanks for all the help

so first of all, i think it's especially important to mention that we're using 2 controllers. one processor for controls and one for fancy sensor inputs (image analysis and whatever else we throw on there). the second processor may be an ARM 3530, so i think kalman filters on the matbotix sonic rangers will do the trick. After reviewing the rules, i found out that the ceiling is 16 feet high, so that should be within the 255 in range of the range finder.

i was going to play around with using the camera and an optical flow algorithm to do position hold, but unless you're looking at a fixed object on the ground with a known size and shape, you cannot use the camera to determine altitude.