Abstract: Device for determining the orientation of an axis, mobile about a point, of a solid in rotation about this axis, particularly a gyroscopic spinner, wherein said device comprises a portion of sphere centered on said point of said axis, of which the surface comprises at least two parts which are respectively absorbent and reflecting for a given radiation, and sensor means sensitive to the radiation reflected by the sphere, the reflecting and absorbent parts being shaped so that the sensor means deliver signals characteristic of the orientation of said axis.

Abstract: An optical device of the periscope type carried on a vehicle, comprising a sighting tube rotatably mounted in the vehicle, a driving member fixed to the vehicle for rotating the tube about its optical axis, and a reflector placed at the other end of the tube and rotatable about an axis orthogonal to the optical axis, further comprising a central unit for forming electrical voltages representative of the pitch angle and the roll angle of the vehicle, a first resolver the rotor of which is driven in synchronism with the sighting tube and the primary windings of which are connected to said central unit, a second resolver supplying a voltage representative of a pre-determined site angle, a third resolver the primary windings of which are respectively connected to one of the secondary windings of the first resolver and to said central unit, a feed-back loop for servoing the output voltage of said third resolver to the output voltage of said second resolver, and means for transmitting the displacement of the rotor

Abstract: A device for stabilizing the site of the sight line in an optical panoramic survey system carried by a vehicle, said system comprising a sighting tube rotatably mounted in the vehicle, driving means secured to the vehicle for rotating the tube about the optical axis thereof, and a reflector disposed at the top of the tube and rotatable about an axis normal to the optical axis, comprising a circular guideway, support means attached to the vehicle for supporting said guideway while holding vertical the axis thereof, a member guided along said guideway, a vertically adjustable member supported by said guided member, a link member with a variable length pivotally connected at one end to said adjustable member, a shaft secured to the other end of said link member, said shaft having an axis which intersects the axis of said guideway, means for imparting to said shaft a rotational movement identical with that of the tube, and means for transmitting the angular displacement from said shaft to said reflector with a 1: