Pixel displacement effects on centroid position accuracy

In order to improve the accuracy of centroiding for high precision miniature star tracker, a method to calibrate the imaging sensor pixel displacement using heterodyne laser interferometry was proposed. And the star position error due to imaging sensor pixel displacement was studied by simulation. The simulation results show that the accuracy of star position can be enhanced from 0.008 pixel to 0.002 pixel by compensating pixel displacement when pixel displacement obeys uniformly distributed over the interval (-0.02, 0.02) pixel. When the additive Gaussian noise in the star image has a normal distribution with mean 0 and standard deviation 5.5, if pixel displacement obeys uniformly distributed over the interval (-0.02, 0.02) pixel, the accuracy of star position can be enhanced from 0.020 pixel to 0.018 pixel after compensation; if pixel displacement obeys uniformly distributed over the interval(-0.04, 0.04) pixel, the accuracy of star position can be enhanced from 0.026 pixel to 0.018 pixel after compensation, which are 31% better than the accuracy without compensation. Simulation results show that calibrating pixel displacement which can significantly improves the star position accuracy can be used as a new method to develop high precision miniature star tracker.