Abstract: A method and apparatus for aligning the mirrors of a laser cavity while the cavity is lasing. The orientation of the reflecting surface of the mirror in a laser cavity is modified by deforming the rear surface of the mirror in order to achieve a desired orientation of the reflecting surface and maintaining the reflecting surface in the desired orientation. In accordance with the preferred embodiment of the invention, the mirror is maintained in a desired orientation with a cavity alignment spring. More particularly, a spring is attached to a projection on the rear surface of the mirror and is adapted to apply a predetermined deflection to the projection. Thus, the spring engages and applies a mechanical force to a flexible member on which the reflecting surface is provided from outside the cavity in order to distort and maintain distorted the reflecting surface to a position which enables the proper laser operation.

Abstract: Data transmitted over an n-state phase-shift keyed transmission system which has an inherently suppressed carrier is recovered using digital processing techniques. The received signal is digitized and a digital representation of the suppressed carrier signal recovered directly from the digital representation of the received signal. The digital representation of the received signal is interacted with the digital representation of the carrier signal to recover the transmitted data. A preferred aspect recovers the carrier by subjecting the digital representation of the received signal to a non-linear processing step to generate the nth order harmonic.

Abstract: A control system suitable for incorporating in control panels and effecting remote control of apparatus includes a light guide bus system including input and output light guides and optical switches carried on a removable optical bridge member bridging in use the input and output light guides so that the switches may be selectively connected into the bus system. Each switch is of a known optically encoding type which on operation of that switch passes its particular control code into the light guide bus system for subsequent decoding and appropriate control of the apparatus.

Abstract: Described herein is a clamping mechanism for attaching and aligning a tubular member, for example a missile launch tube (7), to a support member, for example an optical sight/firing unit (1). The mechanism allows the required electrical connections to power supplies to be made while providing the necessary alignment for the effective launch of the missile system and retaining a rapid reloading cycle for the system.

Abstract: A thrust control valve which is operable to direct a gas supply to provide thrust is disclosed. The gas supply to obtained from a hot gas generator eg a rocket motor combustion chamber, and is directed through a nozzle by the operation of a plunger mounted within a pressure chamber. The pressure in the pressure chamber is controlled by the operation of a solenoid-operated poppet valve which moves between two positions to either pressurize the chamber ie sealing the nozzle with the plunger to provide no thrust, or to de-pressurize the chamber ie allowing gas from the gas supply to exit via the nozzle thereby providing thrust.

Abstract: An optical processor includes a non-linear spatial light modulator defining an array of logic gates and having an output plane 10 ) and an input plane 12. The array is made up of a plurality of cells 14 each containing a plurality of logic gates 16. A lenslet array 18 comprising an array of lenslets 20 associated one with each cell 14 respectively focusses the oututs of the cells onto respective facets 22 of a holographic array 24. Each facet of the holographic array defines a predetermined mapping or routing configuration to map the respective cell onto the input plane 12. The cells may be mapped either precisely onto the predetermined cell of the input plane or in cell-shifted fashion. An optical processor is described which employs the arrangement illustrated in FIG. 1 to enable asembly of a plurality of similar interacting modules for implementing a regular algorithm such as a fast multiplier array.

Abstract: A ring resonator waveguide for a laser gyroscope comprises a ring of waveguide material (2) formed around the inside or outside surface of a hollow cylinder (3) or ellipsoid (4). Such a ring resonator waveguide is made by providing a hollow cylindrical substrate (1), depositing waveguide material (2) on the inside or outside surface of the hollow cylindrical substrate (1), heating the substrate (1) and blowing it to form a cylindrical or ellipsoidal (4) member, and cutting a circular section (5, 6) from the cylindrical member (3) or from a central portion of the ellipsoidal member (4).

Abstract: Solid state imaging apparatus comprising a charge-coupled frame transfer image sensor including an image-sensitive integration region for forming a charge pattern representative of an incident image, first and second storage regions associated with respective opposed ends of said integration region, and charge transfer means for shifting the charge pattern formed in said integration region into a selected one of said storage regions.

Abstract: Where components are drilled by means of a robot a problem occurs when different size holes are needed to be drilled. The existing solution to this problem is to provide a drill unit (including drill bit, chuck and feed device) for each size of hole to be drilled and programme the robot to select the appropriate drill unit from the series of drill units supplied, perform its task, replace the drill unit in its store and select a further drill unit. Thus a complete drill unit is changed for every change in hole size. The presently described arrangement provides means to effect only drill bit change, the chuck and feed unit remaining on the robot at all times. The arrangement also provides means to effect such drill bit change while the chuck is rotating thereby obviating the need to stop and restart every time the drill bit is changed.

Abstract: A deployment mechanism in which a member 2 deploys from a spinning body 1 by centrifugal force is described.A friction arm 6 exerts a retarding torque on the root 4 of member 2 and prevents the member from overshooting its deployed position. The friction arm 6 applies a retarding torque which is proportional to the spin rate of the missile and keeps the resultant deployment torque to within pre-determined limits. The mechanism automatically compensates for a wide range of spin rates.

Abstract: An alternative form of accelerometer is described herein in which an acceleration sensitive element (68, 69) is coupled to a deformable reflector (60) in a lasing cavity (58) to vary the radius of curvature of the reflector in response to experienced acceleration and hence to alter the beat frequency between two transverse lasing modes in the cavity to provide an output signal indicative of the acceleration.

Abstract: An accelerometer includes a flexible beam member, a support and mounting holes. An inertial mass is carried by the beam member and is spaced from the mounting holes. A spring allows the beam to pivotably move in a plane transverse to a first direction. The beam member is resiliently deformable in the first direction and permits relative motion between the inertial mass and the support in response to acceleration. The beam member is also able to move relative to the support in the transverse plane because of the action of the spring to recude the likelihood of damage caused by shock accelerations.

Abstract: An aircraft fuel system adapted for the automatic extraction and dispersion of entrapped puddles of water in an aircraft fuel tank as a function of fuel flow supply to at least one propulsion engine. Scavenge pipes, positioned to be immersed in the puddles at their inlet openings, are connected to a venturi located within a fuel supply duct and arranged such that fuel drawn through the duct by means of a jet pump induces water extraction by suction at the venturi throat which is subsequently broken up within the jet pump and dispersed in the fuel.

Abstract: An arming device for a missile having a rotating tail fin assembly is disclosed. The device includes a distance counter comprising a given length of coiled tape contained within a rotatable drum, the length of the tape being determined by the distance required to be covered by the missile before arming the warhead. The tape is wound onto a shaft driven by the tail fin assembly from the drum which is initially locked to the missile body, and when the tape has been completely wound onto the shaft, the drum is released and is free to rotate through a half-turn to initiate arming of the warhead.

Abstract: A resource allocation system for indicating the optimum allocation of a resource between a series of demands iteratively processes the probability data for each demand to determine for each of a range of amounts of resource available the optimum distribution of the resource between the demands and the resultant probability of successfully overcoming all the demands. The system may be used to predict the probability of success where there is a limited resource available and a predicted series of demands, but it may also be used to assess non-predicted threats and to determine an updated optimum distribution and resultant probability.

Abstract: The equipment for the transfer of fluids such as oil or gas from a drilling rig or platform mounted on the seabed to a ship pitching, heaving and yawing in relation thereto includes an interconnection through which fluid flow can take place. The interconnection has two parts, namely a probe 5 and a probe-receiver 4. The two parts are capable of engagement or disengagement on relative fore-and-aft movement. The equipment also includes a hose 6 to pass fluid to and from the interconnection, one part of the interconnection being mounted upon the platform 1 and the other part being carried by an at least partially spaced stabilized gantry 9 mounted upon the receiver vessel 8. One part of the interconnection 4 is mounted by a releasable anchor and has its hose 6 extendable when the anchor is released. The arrangement is such that the receiver vessel can be temporarily placed in an engagement position adjacent to the platform 1 and the parts 4 and 5 of the interconnection so aligned that engagement can be effected.

Abstract: A conduit system for cables adapted for mounting in a vehicle including constant cross-sectional elongate conduit elements 1 having one or more channels 3 formed therein and retention and locking members for holding the cables within the or each channel at intervals along their lengths. The conduit system may comprise a plurality of straight conduit elements 1 connected end to end, for example in an aircraft fuselage. Alternatively, where a change of direction and/or elevation is necessary, the straight conduit elements may be interconnected by curved joining conduit elements 2.

Abstract: A shared memory system for a plurality of computers comprises a memory linked to the computers via a series of ports which are opened in turn by a control means to grant access to the memory--the operation is such that the memory is apparently always available to each computer and no cumbersome handshake or interrupt routines need be involved. Access may be granted to every computer according to a fixed cyclic sequence or, in sequence, only to those computers which request such access. In the latter case particularly, it may be advantageous to assign a graded priority to the computers and to grant the access to the shared memory in priority order.

Abstract: A disclosed canopy testing using an area imaging device, e.g. a T.V. camera, to view a scene, a cross-hatch pattern say, through the canopy. The viewed image is digitized and stored and a computer evaluates the target image by comparing the apparent positions of its features with their real positions and/or by sensing deviations from straightness of the pattern lines. In a development, a polarimeter or polarization sensitive camera is used to test for hazing and curvature defects.

Abstract: A combined duplexer/mixer especially for use in an FMCW millimetric radar system has a waveguide section containing a fin line or suspended strip structure for responding to the linearly polarized radar return signal passing through the section in one direction while permitting passage of the orthogonally polarized, outgoing signal passing in the other direction. The fin line is coupled via double balanced mixer diodes to an IF output line to produce an IF signal by mixing the return signal with a portion of the outgoing signal tapped off by a field distorting probe, ridge section or like coupling means.