A commercial IMU-based autopilot developed by Krzysztof Bosak from AerialRobotics.
The autopilot is now available only wrapped with EasyUAV or Pteryx UAV which are designed for civilian aerial photography, without relying on the groundstation in field conditions.

The platforms supported must be rudder+elevator driven what is compatible with the mission, allowing easier maintenance and assembly and moderately stable platforms (however not strictly required).
This autopilot is not using the pitot tube, while still being fully stable in unlimited loiter.

Links:

• Features
• DIY Drones forum

You can see the range of flyable platforms here: