[Paparazzi-devel] Compensating for drift in inertial autopilot

[Adam Williams]

So I'm putting together a shopping list for a helicopter autopilot based on
autopilot.sourceforge.net, http://www.sparkfun.com, 
<http://www.sparkfun.com> and anecdotal information on the
internet.  Sorry but can't find any implementation notes on 
http://savannah.nongnu.org/projects/paparazzi/.

Hovering a helicopter seems to require a 3-axis accelerometer and a 
2-axis gyroscope.  Autopilot.sourceforge.net claims they hovered a 
helicopter on just this information.

One problem isn't being addressed anywhere:  How do the autopilots 
compensate
for the drift in the gyroscopes?  Do the accelerometers compensate for 
it?  Do they need a GPS
to reset periodically?  Do they just have a time limit before requiring 
pilot intervention?
I would like to know if more components are required for the drift issue 
before buying anything.