Helmet with visor position detection and associated helmet position detection

A helmet 2 has a head-up display comprising an image source 3, collimating optics 2 and a fixed visor 1 onto which the image (e.g. navigation or aiming symbiology) is cast for superposition on the exterior. A helmet position detection system includes mobile parts 21 on the helmet and fixed parts 20 in a cockpit so the posture of the helmet can be used to servocontrol weapons etc systems.. The helmet 2 has a substantially spherical mobile visor 10 that is able to occupy a position of use and a stowage position (shown in dashed lines). The helmet comprises detection means 14 for detecting the position of the visor and the helmet position detection system 20, 21 has means for introducing an angular correction in the helmet position measurements when the visor is detected in the position of use by the visor detection means. The detection means are preferably optical sensors.