STAR TRACKER DEVICE HAVING AN ACTIVE PIXEL SENSOR

The invention relates to an active-pixel-sensor (APS) apparatus for use in a star tracker device including an imager chip, said imager chip comprising an array of photo-diodes operating as optical pixels, and a logic circuit. The logic circuit is configured for reading out a pixel signal depending on an amount of light irradiated during a predetermined integration time and resetting the optical pixel upon termination of the predetermined integration time processing the pixel signals and to output the modified signals and for performing a non-destructive readout of the pixel signal during the integration time. In order to distinguish Single-Event-Upset (SEU) contributions to the signal from star signal contributions, it is proposed to further configure the logic circuit to detect whether or not a discontinuity has occurred in the pixel signal during the integration time, and to modify the signal depending on the result of this detection.