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Hu X.-D.,The Flight Automatic Control Research Institute of AVIC | Hu Q.,The Flight Automatic Control Research Institute of AVIC | Lei X.,The Flight Automatic Control Research Institute of AVIC | Wei Q.,The Flight Automatic Control Research Institute of AVIC | And 2 more authors.
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2014

Star centroid extraction from object image in center of mass is the important basis of star sensor. For the star image obtained by daytime star sensors under complicated circumstances, a method of star centroid based on multiframe incremental is proposed by using the mathematical model of Gaussian point distribution function. By optimizing the multi-frame iterative image gray scale, the influence of random noise is eliminated and the signal-to-noise ratio is improved. Then, by utilizing weighted squared centroid algorithm, the star centroid is calculated to extract the star centroid from the star image. The simulation experimental results show that the method has excellent anti-interference ability and stability, and the centroid extraction precision is increased with the iteration frames. When the number of iterations reaches 100 times the extraction precision is increased with the increasing of iteration number and could approach 0.1 pixel, which is suitable for low signal-to-noise ratio. This algorithm is simple, less computations, and can achieve real-time processing of video image information. It can effectively improve the positioning precision, and satisfy the application requirements of daytime star sensors. Source


Hu X.,The Flight Automatic Control Research Institute of AVIC | Wang W.,The Flight Automatic Control Research Institute of AVIC | Hu Q.,The Flight Automatic Control Research Institute of AVIC | Lei X.,The Flight Automatic Control Research Institute of AVIC | And 3 more authors.
Chinese Optics Letters | Year: 2014

The stray radiation suppression in Cassegrain family optical system is presented. The design method for ultra-short outer baffle with honeycomb structure is proposed. Meanwhile the constraint formulas for designing the geometries of primary baffle and secondary baffle are deduced when basing the characteristic and taking vignette into account. According to the ray trace simulated data, the point source transmittance values of the baffle are less than 1010 when incident angles are larger than the rejection angle. The honeycomb-look front baffle guarantees a comparable performance of stray light suppression with traditional tube baffle, while reducing the size greatly. © 2014 Chinese Optics Letters. Source

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