Aiming system for portable weapons comprising - a display device to be worn on the head of a user comprising a visor that can be viewed by the user, - a portable weapon defining a firing trajectory, - electronic means for managing information received from three pairs of sensors (13B-14B, 13A-14A, 13C-14C), in particular a first (13B-14B), a second (13A-14A) and a third pair (13C-14C) of sensors, wherein a first sensor of each pair is arranged on said portable weapon and the second sensor of each pair is arranged on said display device; said first pair (13B-14B) comprising first sensors adapted to detect angular velocity in space of said weapon and of said display device for the evaluation, by virtue of said electronic means, of the orientation in space of said weapon and display device; said second pair (13A-14A) comprising second sensors adapted to detect the orientation of the terrestrial magnetic field; said third pair (13C-14C) of sensors comprising third sensors (13C, 14C) adapted to determine the acceleration in space of said weapon and of said display device for the evaluation, by virtue of said electronic means, of linear displacement in space of said weapon and display device; said first and third sensors being of the inertial type; - reference means (16A, 16B) adapted to locate the weapon and display device at a known mutual distance and angular position; said reference means (16A, 16B) being adapted to define an initial orientation and an initial position in space for the weapon and the display device which must be known to the system in such a manner as to have initial data from which to carry out the variations in orientation and position detected by the sensors; said electronic means being configured for - placing in mutual relation the Z r position and orientation in space of said weapon and of said display device by use of the information received from said pairs of sensors; said placement in mutual relation comprises the cooperation of said reference means (16A, 16B) and said sensors in a initialization step in which the mutual position and orientation in space of the weapon and of the display device are defined, so that at a time t=0, the weapon and display device are at a known mutual distance and angular position, and - representing in said visor, both on the basis of said mutual position relation, and on the basis of said mutual orientation relation, at least part of the firing trajectory of the weapon. - a display device to be worn on the head of a user comprising a visor that can be viewed by the user, - a portable weapon defining a firing trajectory, - electronic means for managing information received from three pairs of sensors (13B-14B, 13A-14A, 13C-14C), in particular a first (13B-14B), a second (13A-14A) and a third pair (13C-14C) of sensors, wherein a first sensor of each pair is arranged on said portable weapon and the second sensor of each pair is arranged on said display device; said first pair (13B-14B) comprising first sensors adapted to detect angular velocity in space of said weapon and of said display device for the evaluation, by virtue of said electronic means, of the orientation in space of said weapon and display device; said second pair (13A-14A) comprising second sensors adapted to detect the orientation of the terrestrial magnetic field; said third pair (13C-14C) of sensors comprising third sensors (13C, 14C) adapted to determine the acceleration in space of said weapon and of said display device for the evaluation, by virtue of said electronic means, of linear displacement in space of said weapon and display device; said first and third sensors being of the inertial type; - reference means (16A, 16B) adapted to locate the weapon and display device at a known mutual distance and angular position; said reference means (16A, 16B) being adapted to define an initial orientation and an initial position in space for the weapon and the display device which must be known to the system in such a manner as to have initial data from which to carry out the variations in orientation and position detected by the sensors; said electronic means being configured for - placing in mutual relation the Z r position and orientation in space of said weapon and of said display device by use of the information received from said pairs of sensors; said placement in mutual relation comprises the cooperation of said reference means (16A, 16B) and said sensors in a initialization step in which the mutual position and orientation in space of the weapon and of the display device are defined, so that at a time t=0, the weapon and display device are at a known mutual distance and angular position, and - representing in said visor, both on the basis of said mutual position relation, and on the basis of said mutual orientation relation, at least part of the firing trajectory of the weapon. - placing in mutual relation the Z r position and orientation in space of said weapon and of said display device by use of the information received from said pairs of sensors; said placement in mutual relation comprises the cooperation of said reference means (16A, 16B) and said sensors in a initialization step in which the mutual position and orientation in space of the weapon and of the display device are defined, so that at a time t=0, the weapon and display device are at a known mutual distance and angular position, and - representing in said visor, both on the basis of said mutual position relation, and on the basis of said mutual orientation relation, at least part of the firing trajectory of the weapon.