A method is provided for readjusting a worn head-up display via an SVS synthetic vision system for viewing information pertaining to the piloting of an aircraft, the information being conformal with the real outside world, comprises steps consisting in: launching the readjusting method by displaying all or some of the conformal piloting information in a readjusting state, frozen on the display with respect to head movements and free with respect to the movement of the aircraft; then carrying out a series of N measurements of relative orientations {circumflex over (K)}l of the head corresponding to targeting actions Vi that superpose the various elements of piloting information displayed in the readjusting state with corresponding landmarks of the real outside world; then conjointly determining the relative orientation M01 between the display D0 and the tracking mobile element D1 and the relative orientation M3t of the inertial device D3 with respect to the Earth on the basis of a system of dual harmonization equations using the measurements {circumflex over (K)}l.