Sparse-optical-flow-based autonomous navigation scheme for unmanned aerial vehicles

An autonomous navigation scheme for unmanned aerial vehicles (UAVs) based on sparse-optical-flow is presented. The scheme can give navigation information without the known land-based cooperative target. Instead of tracking the known target, a sparse-optical-flow method is adopted. Two indirect and feedback-error-correction-based H_∞ filters are built to integrate the measurement data of strapdown-INS, optical flow, electronic compass, altimeter system and laser range finder, and the estimations of altitude, attitude angles, and horizontal velocities of UAV could be given. The navigation scheme can be used in the low altitude flying stage, the approach stage and other stages of UAV when it is not preferable to build the manmade or known land-based cooperative targets for computer vision equipment. The autonomous navigation scheme can run properly on the real-time simulation system for autonomous landing of the UAV.