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Active pixel sensor apparatus for use in a start tracker device
| 539 - Abstract: |
| ESA presents a novel active pixel sensor apparatus for use in a star tracker device. The technology has been designed to make star sensors lighter, smaller and cheaper than the state of the art, but can be applied to several types of imaging devices. The organisation offers the technology for licensing. |
Description of the offer:
Star tracker images are known to be corrupted by so-called single event upsets (SEU) appearing as points and streaks destroying the integrity of the image. The single event upsets are due to solar flares and other cosmic radiation and are particularly bothersome in missions approaching the sun.
Recently, imager chips of active pixel sensor (APS) type have been employed in star tracker apparatuses. Moreover, it has been proposed to integrate additional functionality with APS sensors in this application. The object of the invention is to provide an active pixel sensor apparatus being capable of performing an on-the-fly processing of single event upsets and in particular, to enable an on-the-fly rejection of these single event upsets in order to reduce the complexity of the image processing in star tracker apparatuses.
This technology is an active-pixel-sensor (APS) apparatus for use in a star tracker device. It includes an 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.
Innovations and advantages of the offer:
- Simplification of proximity electronics
- Totally digital electronics
- Simplification of supply voltages and relevant DC/DC converter
- Possible improvement in radiation survivability (especially protons)
- Reduced size and mass
Domain of Application:
- Other scanning related (including optical mark sensing and image processing) monitoring equipment