So these questions may be bit a daft, but why do all the IMU's have 3 accelerometers on them?
I just picked up a memsic 2125 dual axis sensor from radio shack for $30. Wouldnt 2 of these give you "4 axis" of angle input (roll+pitch+yaw+... 1 extra)
I've also heard talk that the ArduPilot cant handle the processing required for the IMU and then the nav also. What processing goes into reading the IMU (sorry i know im being lazy.. i could just look at the code). The readings from memsic chip seems to be pretty stable.. just summing a small sample (5-10) and shifting the result.
im new to arduino stuff.. so bear with me, im just curious, It seems a very simple stabilization unit could be made from 2 of these memsic chips and a small amount of code. It seems too simple.. i must be missing some thing ;)