A method for harmonizing a frame of reference of an angular positioner to receive a moving body relative to the terrestrial frame of reference, the angular positioner carrying a measurement device for taking inertial measurements of the moving body, the method includes obtaining, using inertial measurements taken by a measurement device on-board the angular positioner during at least one predetermined operating period, values representative of a local magnitude of gravity as perceived by the measurement device and/or of a speed of rotation of the earth, the angular positioner being held stationary during the at least one operating period; evaluating, using the obtained values, at least one angular bias affecting the frame of reference of the positioner; and harmonizing the frame of reference of the positioner relative to the terrestrial frame of reference by compensating for the at least one angular bias as evaluated in this way.