Abstract: A gas cell, preferably in the shape of a hemi-sphere, forms a transparent enclosure for helium or an alkali metal vapour. A coil forms an A.C. magnetic field H.sub.1 in the enclosure, the magnetic field having multi-directional field lines. A lamp or lamps, comprising either helium or alkali metal vapour, direct circularly polarized resonance radiation at the enclosure such that the radiation rays travelling through the enclosure are multi-directional. A photodetector or photodetectors detect the radiation rays after they have passed through the gas cell. The multi-directionality of the radiation rays and the A.C. magnetic field H.sub.1 ensures that the magnetometer will not possess dead-zones.

Abstract: A sheet of material for forming the screen is mounted on a cylindrical forming drum and is blow formed, by hot air under pressure, to provide a projection screen. The resulting screen is curved along the width thereof and curved along the length thereof, and is formed from a single, continuous, sheet of material so that the screen is a stand-alone screen.

Abstract: A six-axis force transducer is mounted on the flight controller and provides three independent orthogonal linear force components of the applied force and three independent orthogonal torque components of the applied force. Change in position is measured by a motorized spool connected to a high resolution shaft encoder. A small diameter thread is wound around the spool via a mechanically driven threading device. The free end of the thread is connected to a fixed point in the cockpit. The output of the transducer and the shaft encoder are fed to a microprocessor which calculates net force, in accordance with well known formula, and net position, from calibration data.

Abstract: A fiber optic helmet mounted display system produces a replica of an image derived from an image source for viewing by an observer. The system includes a wide angle eyepiece mounted on the helmet in the line of sight of the observer. Fiber optic cable means transmit the image from the image source to the eyepiece whereby to produce the replica of the image in the line of sight of the observer, the replica appearing to originate at a distance.

Abstract: A non-contact sensing system for monitoring the position and orientation of a rigid body in space having at least three distinct point light sources mounted on the rigid body. At least two position sensor heads are fixedly mounted within detection range of light from the light sources, each position sensor head having a position sensitive detector. The lights are illuminated one at a time and in sequential arrangement and a processor computes the position in three-dimensional space of an illuminated light source with data provided simultaneously by both position sensitive detectors. The processor means also computes the position of the object in all six degrees of freedom using the three-dimensional positional data of all three light sources.

Abstract: A system for counteracting the effect of helicopter vibrations on a seat in the helicopter which seat includes a plurality of controllable air cells includes a means for varying the pressure of the cells and transducer means for sensing cell pressure and vibrations and for providing electrical signals representative thereof. Control means provide signals for controlling the means for varying and processing means process the electrical signals and provide driving signals for driving the control means. A processing means converts the electrical signals to provide driving signals which drive the control means to control the means for varying so as to counteract the changes in pressure in the air cells due to vibrations to eliminate or reduce the changes in pressure with this system, the pilot is isolated from the helicopter compared with prior art systems where the seat is isolated from the helicopter.

Abstract: The invention relates to a motion simulator system, for example, a flight simulator system. In accordance with the invention, the system is driven by command signals representing both position and acceleration, and a circuit is provided to process and combine the signals to provide a system command signal. High frequency position command signals, and low frequency acceleration command signals, are eliminated by their drive circuits, and all command signals are varying electrical voltages.

Abstract: The invention relates to a 6 degree of freedom hand controller. The hand controller includes a handgrip member which is substantially spherical in shape and which includes a point disposed substantially centrally of the member. An elongated shaft member supports the handgrip member such that the handgrip member is rotatable, from an initial position, about the point. The rotational motion of the handgrip member about the point is resolvable into motion about a pitch axis, passing through the point, a roll axis at right angles to the pitch axis and also passing through the point, and a yaw axis, at right angles to both the pitch axis and the roll axis and also passing through the point. The elongated shaft member is movably supported such that the handgrip member is movable, from the initial position, in translational motion resolvable into motion along the pitch, roll and yaw axes and through the point.