Abstract: An autonomous magnetic observatory is provided that includes a scalar magnetometer for measuring the modulus of the local magnetic field vector F; an angular magnetometer for measuring the vertical direction, the direction of geographic North, and the direction of the local magnetic field vector F; a variometer for measuring three variations in the local magnetic field vector F; a clock; and a controller. In which observatory, the controller is configured to control and manage the orientation of sensors, to acquire the measurements of the variometer, of the scalar magnetometer, of the angular magnetometer and of the variometer, and to process the acquired measurements in order to obtain automatically, the local magnetic field vector F and the errors in the measurements associated with each instrument.