  This paper considers onboard control of a small-sized quadrotor using a
strapdown embedded optical flow sensor which is conventionally used for desktop
mice. The vehicle considered in this paper can carry only few dozen grams of
payload, therefore conventional camera-based optical flow methods are not
applicable. We present hovering control of the small-sized quadrotor using a
single-chip optical flow sensor, implemented on an 8-bit microprocessor without
external sensors or communication with a ground control station. Detailed
description of all the system components is provided along with evaluation of
the accuracy. Experimental results from flight tests are validated with the
ground-truth data provided by a high-accuracy reference system.
