A positioning computer for a satellite intended to move in an orbital plane, the satellite being intended to include: a body having an Earth face defining an axis Z of the satellite intended to point towards the Earth, at least one optical system for communicating with another satellite located in the orbital plane, the first optical system being intended to be located on an anti-Earth face and have a field of view in azimuth around the axis Z, the field of view being limited by an obturation angle due to the body. The computer is adapted to obtain a parameter representing a solar angle defined by the Sun with the orbital plane, and to perform the calculation of a parameter representing the yaw angle of the satellite using at least the parameter representing the solar angle and a parameter representing the obturation angle.