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Spacecraft attitude motion compensation approach to deal with internal slewing payload motion is addressed in this study. The internal payload motion is generated by a steering mechanism such as steerable gimbals for image acquisition as well as error correction due to orbital and attitude errors. Disturbance caused by payload motion in general cannot be measured using sensing devices. The disturbance...
Under GPS-denied conditions, an inertial navigation diverges easily due to integration drift in the measurement of acceleration and angular velocity. Therefore, a terrain relative navigation (TRN) is applied to correct the drift error for precise lunar landing mission. Diverse sensors are used for the TRN in these days, such as a Light and Detection and Ranging (LIDAR), laser altimeter, and optical...
The robust marker tracking and relative navigation algorithms are presented for precise UAV vision-based autonomous landing. To recognize the marker in close-range, the concentric circles are adopted as the marker with ellipse fitting algorithm based on Direct Least Square. We assume that IMU provides vehicle's attitude and altitude so that we consider GPS-denied situation. Also multiple ellipses...
In this paper, we present close-range vision navigation and guidance for rotary autonomous landing. To consider the case which the entire shape of the marker cannot be shown in close range, we suggest a marker design consists of ‘H’ shape and concentric circles. To recognize circles using only portion of the marker, ellipse fitting method by direct least square is used. Thus, the pixel coordinates...
In this paper, we studied for the ellipse fitting problem when an unmanned aerial vehicle (UAV) reaches near a landing marker for vision-based autonomous landing. Due to limited field of view of a camera, the entire shape of the landing marker cannot be captured as the vehicle approaches it. Also, depending on the vehicle's pose, the shape of the maker is shown distortedly. In order to overcome these...
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