This paper describes the concept of a new algorithm
to control an Unmanned Aerial System (UAS) for accurate
autonomous indoor flight. Inside a greenhouse, Global Positioning
System (GPS) signals are not reliable and not accurate enough. As
an alternative, Ultra Wide Band (UWB) is used for localization.
The noise is compensated by combining the UWB with the delta
position signal from a novel optical flow algorithm through a
Kalman Filter (KF). The end result is an accurate and stable
position signal with low noise and low drift.