StarTracker camera

Star tracker is an avionic instrument which estimates the attitude of a spacecraft through the stars observation. It is based on a camera to acquire images of the sky, interfaced with a processor, which performs pattern recognition of the stars in the field of view by means of a star catalog to estimate its attitude with respect to the celestial sphere.

The electronics were developed for the camera based on a specialized 500 x 500 pixel CMOS image sensor. This sensor allows for multiple Regions of Interest (RoI) per frame with programmable number and size. These additional features aim to minimize the amount of data that needs to be delivered off-chip and reduce power consumption.

As the image sensor is in the early stages of development, the goal was not only to develop front-end electronics but also to create a platform for future activities by other teams. To achieve this, a microcontroller-based control board was designed with the following features:

  • Low-level sensor interfacing and image readout
  • Implementation of region-of-interest functionality, allowing partial readout of the image
  • Hardware and software ROI tracking
  • Data communication with a PC (either through dedicated software or Python code)

The use of a microcontroller processor, reprogrammable with a high-level language, and the possibility of interfacing with the sensor from a Python script minimize the time required for future software development in research and development projects.

Recently, the second iteration of the electronics has been produced with three major improvements:

  • The hardware has been adapted to accommodate the new version of the chip with higher image resolution (1Kx1K)
  • The communication speed has been drastically increased, moving from USB2 to USB3.
  • Unnecessary blocks have been removed from the development board, optimizing its size and power consumption.