A mortar fire control system for indicating azimuth, elevation and cant alar orientations of a mortar barrel. The system comprises a 3-axis optical head mounted adjacent the mortar barrel which emits light pulses in two predetermined directions, 90.degree. apart, towards aiming stakes. Two aiming stakes located at approximately 50 meters and 100 meters from the mortar are aligned along one of the predetermined directions while a third aiming stake is situated 90.degree. away from the first two aiming stakes and at a distance of approximately 50 meters from the mortar. Each of the aiming stakes is provided with an optical transponder for receiving the light pulses emitted from the optical head and for retransmitting a light pulse to said optical head. The light pulses received by the optical head are converted into digital information representative of the azimuth, elevation and cant angular orientations of the mortar barrel relative to predetermined initial values of each of these three parameters.