Research On Detector Autonomous Navigation Based On Image Information

Detector landing on star surface can get a lot of surface topography on the surface of star information, to collect rock samples, etc for scientific research. Deep space exploration targets are far away from earth, and short duration of objects in landing process. So remote communication between ground control stations and deep space probe can not meet the requirement of the deep space exploration tasks. Therefore, how to use image information to gain more scientific observation and navigation information is a key technology in astrophysics field.This paper combines the national natural science foundation project-"tracking strategy and error analysis of independent feature point in star landing process". The spacecraft autonomous optical navigation algorithm based on image information is studied. The main research contents and innovation points include:1. The research significance, background and development situation at home and abroad of autonomous navigation system based on image information are introduced. Analyze advantages and disadvantages of various autonomous navigation method and its applicable occasions. Combining deep space detection with and task process of autonomous optical navigation, the paper makes a brief analysis to optical navigation principle.2. For completing accurate initial positioning tasks in detector landing phase, SIFT algorithm is used to extract feature points of the star surface. Feature points are matched with the image database, the algorithm solve the image matching problem when the image exists large rotating and zooming. According to matching points of real shot image and image database, linear2D/3D pose estimation method is used to estimate position.3. Detector navigation in the landing process needs the navigation camera image information, which requires that there should be plenty of overlap between adjacent two images. So the detector can extract enough inter-frame matching feature point to estimate detector motion parameters. For above mentioned problems, motion limiting conditions of the detector for having sufficient overlapping area between adjacent images are studies.4. Aiming at the positioning in detector landing process, inter-frame motion estimation method based on pole-constraint principle is studies. Use fundamental matrix to determine the relative position and attitude of the detector. The fundamental matrix is determined by tracking the feature point location. All six degrees of freedom motion parameters are obtained through ranging information. The simulations verify that the method has higher accuracy.