Solar sensor

Solar sensors on spacecraft act as orientation sensors, determining the spatial position of the device relative to the Sun. Very often they are used to roughly orient solar panels to the Sun. It should be noted that it is impossible to fully determine the orientation of the spacecraft only from the readings of solar sensors - there will always be uncertainty with the angle of rotation of the spacecraft around the direction "apparatus-Sun".

The sensor returns readings from two sensors examining the left and right hemispheres, respectively. When one of the sensors is illuminated, the angle of pointing at the Sun can be estimated by the level of illumination. When two sensors are illuminated, a more correct approach would be to use the ratio of light levels on both sensors.

Calculating the specific dependencies of the angle on the illumination levels is called calibrating the sensor to different conditions. Nevertheless, even without calibration, sensors of a similar design can be used to point at the sun by analyzing the mutual illumination of the right and left hemispheres of the sensor.