Abstract: A sighting apparatus is provided for aiming an optical device mounted on a moving platform and having both coarse and fine adjustment. The sighting apparatus includes a fixed base and an outer support ring that is capable of rotation by a drive motor about an azimuthal axis perpendicular to an axis defined by the outer support ring. A support hub is rotatably supported within the outer support ring and is capable of rotation by a drive motor about an elevational axis substantially coincident with the axis defined by the outer support ring. At least one mounting plate is supported by the support hub and the mounting plate is capable of movement about the azimuthal and elevational axes relative to the support hub, and the mounting plate is capable of movement about a roll axis perpendicular to the azimuthal and the elevational axes.

Abstract: An absolute pressure regulator valve assembly for controlling the absolute pressure (P.sub.C) of a fluid source. The absolute pressure regulator valve assembly includes a hollow housing having an inlet port and a discharge port. The inlet port is in fluid communication with the fluid source. The discharge port is associated with a valve seat. A bellows assembly is positioned within the housing. The bellows assembly has an open first end and a closed second end. The first end is gas-tight sealed to the housing and is in fluid communication with a means for providing a reference pressure (P.sub.R) within the bellows assembly. A valve closure element is attached to the closed end of the bellows assembly. The valve closure element is positioned relative to the valve seat wherein motion of the bellows assembly provides opening and closure of the discharge port.

Abstract: An improved two axis electromagnetically operated actuator is disclosed.

Abstract: Gimbal comprised of four concentric cylindrical shells rotatively attached to each other by three pairs of bearings or flexures. The innermost shell is rigidly attached to a suspended instrument. The outermost shell is attached to a vehicle. Each of the three pairs of bearings are colinear and define three axes of rotation which intersect at a point. None of the three axes are coincidental with a line of sight emanating from the instrument, and two of them are nonorthogonal. The gimbal provides the instrument with freedom of rotation about any axis relative to the vehicle, including about the instrument's line of sight, without the line of sight being vignetted by a bearing or any other gimbal structure. The respective angles between the three axes of rotation are set to minimize the exposure of the gimbal to gimbal lock, as well as to minimize the onset of secondary disturbances that occur when gimbal lock is approached.