An autonomous lifebuoy includes a body, an electric power supply, a propelling module and a control unit configured to control the autonomous lifebuoy so as to automatically guide the autonomous lifebuoy towards a person overboard in water, during a man overboard (MOB) situation. The control unit includes at least one communication module, a non-volatile memory, a graphics processing unit (GPU) configured to perform an image comparison and a microcomputer configured to make calculations, based on at least the image comparison performed by the graphics processing unit (GPU), and issue commands to at least the propelling module to propel the autonomous lifebuoy towards the person overboard in the water during the man overboard (MOB) situation.