A system for determining the true airspeed vector, defined by a magnitude and by a direction, of an aircraft comprising a fuselage, comprises four laser anemometers each having a single measurement path so as to measure a local component of the true airspeed and being distributed in different locations around the fuselage of the aircraft; and means for calculating the magnitude and direction of the true airspeed vector of the aircraft using the four measurements of components of the true airspeed.