Control of a quadrotor helicopter using the COMPASS (BeiDou) system and on-board vision system

In this paper, the COMPASS (or BeiDou) navigation satellite system is utilized for the autonomous flight control of a micro quadrotor helicopter. The CEP (circular error probable) of the COMPASS system is up to 10 m, which is about 10 times higher than the widely used GPS system (Global Positioning System). To overcome limited position accuracy associated with the COMPASS system, an onboard vision system is employed to provide high accuracy translational velocity estimations. By fusing the COMPASS system with the vision-based velocity measurement, accurate and drift-free position estimation can be obtained. In addition, a nonlinear flight controller is utilized to improve the trajectory tracking ability. Finally, the validity and practicability are verified by the real-time experimental results.