Method for selecting observation triangle before star map matching

Abstract

The invention relates to a method for selecting an observation triangle before star map matching. The method comprises the following steps: primarily selecting the observation triangle; performing second optimization screening on the observation triangle, wherein the screening conditions are that the minimum edge for forming the observation triangle on an image surface has more than dmin pixels, and the minimum included angle in the observation triangle on the image surface is larger than thetamin. Compared with the conventional method, the method for selecting the observation triangle before the star map matching can improve the 60.8% probability of one-time matching success and posture output, can preferentially select three groups of observation triangles consisting of brighter stars to recognize and verify in the practical engineering, namely having 77.5% probability to improve success rate of three times of matching and posturing, and greatly improves the time consistency of every frame of all day sphere posturing output.

Description

technical field [0001] The invention relates to the technical field of satellite autonomous navigation, in particular to a method for selecting an observation triangle before star map matching. Background technique [0002] In actual engineering, the star sensor is mainly based on the triangular star map recognition algorithm to determine the attitude. The triangular star map recognition algorithm uses the observed stars appearing in the field of view of the star sensor to form an observation triangle, and uses the principle of congruent triangles as the matching identification standard. Selecting an appropriate observation triangle can improve the success rate of the star map recognition algorithm, reduce the amount of calculation in the matching process, and improve the performance of the real-time output attitude of the star sensor. Zhang Guangjun and others proposed a method for selecting an observation triangle, the principle of which is to select an observation triang...

AI Technical Summary

Problems solved by technology

Since in the actual situation, the selected N B There may be double stars or three bright stars in the field of view where the positions of two stars are approximately in a straight line, so there will be a lot of redundant matching, which will prolong the recognition time, which will lead to the failure of star map recognition or large output errors attitude

Take N B =6, for traversal imaging of the whole celestial sphere, the probability distribution of the number of observation triangles that cannot be identified or output a large error attitude in the statistical field of view, such as figure 1 As shown, within the scope of the entire celestial field of view, among the 20 preferentially selected observation triangles, an average of 7.74 observation triangles cannot be recognized or output a large error attitude, that is, there is a probability of 38.7% in each star map recognition It is impossible to directly output the final attitude at one time. In the actual star map recognition process, the amount of calculation required to match the star map once is much greater than the calculation amount required to select the optimal observation triangle in the field of view, and sometimes even if the star map recognition is successful, but Because the position of the observed star in the field of view is approximately a straight line, the normal attitude cannot be output, and the observation triangle needs to be re-selected for matching and recognition. Therefore, this will seriously affect the real-time performance of the star sensor output attitude

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