"Nice.
Now put a magnetometer on the controller to dynamically set your own (virtual) north and kids won't be disoriented when flying. You would point a direction with the controller, push the joystick and the quad would fly in that direction. =)"
The term "shield" is not in the glossary. I guess it means the same as "turn rate limiter". And again i guess the purpose of such a device is to limit the maximum variation speed of any command (gas, pitch, roll, or yaw).
I subscribed to answer (shortly) to this question and because I really like reading your stories with home-made UAVs. I intend to start a small project on my own when i'll be finished with writing my PhD manuscript. But enough about…"