A Method of Star Spot Center-of-Mass Localization Algorithm for Star Sensor Under Highly Dynamic Conditions

The starlight guidance system calculates the vehicle attitude information by observing the stars’ position through the star sensor. When the star sensor operates under high dynamic conditions, the motion blur phenomenon exists in the images taken by it, which seriously affects the computational accuracy of attitude solution. In this article, based on the motion characteristics of the vehicle under high dynamic conditions, we study and derive the imaging model of the blurred star spot under high dynamic conditions. On this basis, we use the least-squares method combined with the simulated annealing algorithm to fit the trajectory of the cor- responding star spot. The trajectory fitting is based on the information of multiple star streaks in the star field image. And finally, we calculate the center-of-mass coordinates of the star spot. Simulations and experiments demonstrate the feasibility and effectiveness of the method. The fitting error is less than 0.3 pixels for the angular velocity vector [10°/s,0°/s,10°/s] and exposure time 200 ms, which is an improvement of at least 0.1 pixel compared with previous studies.