1. A method of embedding images from other sources within images captured by a viewing device in motion, by transmitting and analyzing the spatial coordinates of the viewing device during acquisition of a sequence of video images (I) while the viewing device is moving through space along a trajectory (t) determined with respect to a defined reference point, the method comprising: a preliminary step consisting of attaching said viewing device to a first subsystem which contains an inertial sensing unit delivering data signals representing spatial coordinates and instantaneous inclination and the focal length of said viewing device with respect to said defined reference point, wherein the first subsystem is removable from the viewing device; a first step of acquiring, in real time, of said data signals during the movement of said viewing device along said trajectory (t) and the transmitting of said data signals to a second subsystem which includes equipment for processing said data signals using a stored software program; and a second step of processing said data signals, either in real time or deferred for later analysis, so as to determine said spatial coordinates of the viewing device, and improving the quality of the acquired data signals by applying an image analysis procedure, wherein error corrections to the data signals delivered by said inertial sensing unit is done by applying the image analysis procedure, included among the stored software program contained in a data processing unit.