Fig. 1. Flow chart of star image sampling process

Fig. 2. Flow chart of centroid algorithm based on star image resampling

Fig. 3. PSF and effective PSF in defocused optical system

Fig. 4. Frequency spectra of PSF and effective PSF in defocused optical system

Fig. 5. Simulation results of horizontal coordinate errors obtained by different algorithms when system only has defocus aberrations. (a) Traditional centroid algorithm; (b) resampling-based centroid algorithm

Fig. 6. Simulation results of horizontal coordinate errors obtained by different algorithms when system has defocus aberrations and comas. (a) Traditional centroid algorithm; (b) resampling-based centroid algorithm

Fig. 7. Equipment for star centroid error measurement

Fig. 8. Comparison between single star image and reference star image. (a) Single star image; (b) reference star image

Fig. 9. Experimental results of horizontal coordinate systematic errors obtained by different algorithms. (a) Traditional centroid algorithm; (b) resampling-based centroid algorithm

Fig. 10. Experimental results of horizontal coordinate systematic errors obtained by traditional centroid algorithm after compensation