Precise Binocular-Based Navigation and Guidance for Autonomous Landing on Small Body
- Paper number
IAC-06-A3.P.5.01
- Author
Dr. Zhang Zexu, Harbin Institute of Technology, China
- Coauthor
Mr. Pingyuan Cui, Harbin Institute of Technology, China
- Coauthor
Mr. Yang Tian, Harbin Institute of Technology, China
- Coauthor
Mr. Weiguo Zhong, Deep Space Exploration Research Center, China
- Year
2006
- Abstract
A precise navigation and guidance algorithm based on the binocular vision techniques for autonomous landing on asteroids is presented. To detect and recognize targets from image sequences effectively and fleetly, the sign lamps representing targets are first thrown on the surface of small body. The wavelength and bandwidth of the sign lamps are identical with that of the binocular cameras, which makes the detection and recognition of targets from image sequences easy and fast. Considering landing the asteroid in the day or night, the range of wavelength of the sign lamps may be about 750 nanometers to 1 millimeter. Secondly, using the binocular vision algorithm of perspective projection, the ego-motion parameters are computed with respect to the camera coordinate system from the corresponding feature points of two frame images. The ego-motion parameters describe the velocity and gesture of the probe and distance from the probe to the feature points. The real-time observed orbit of the probe is determined. To overcome the lost of feature points, the Kalman filter is used to predict the future positions of feature points, which could improve the robustness of algorithm. Thirdly, the desired descent altitude and velocity to satisfy the requirements of soft landing on asteroids is planned, using the coordinate transformation from the coordinate system of camera to that of asteroid. These data planned can be passed directly to the probe guidance and control system to enable rapid execution of safe and precise trajectories. Finally, the variable structure control is then used to design the tracking control law to ensure the fast and accurate response and robustness of guidance law. Computer simulations have demonstrated the satisfactory performance of the algorithms for safe landing on small body with assumed physical environments and simulated landing area.
- Abstract document