Abstract: A prismatic collimating device to collimate image bearing light is disclosed. The prismatic collimating device comprises a first prism and a second prism arranged to receive and collimate a light beam. The first prism comprises an output surface adjacent to an input surface of the second prism. The first prism and second prism are arranged such that the light beam undergoes total internal reflection and refraction at both the output surface of the first prism and the input surface of the second prism. Each of the first prism and second prism comprising at least three optically powered surfaces.

Abstract: A cavity system for use on a vehicle is provided. The cavity has a front edge and/or a rear edge and longitudinal edges. The front and/or rear and longitudinal edges define an opening. The cavity comprises at least one elongate flow partition protruding from a surface adjacent each longitudinal edge of the cavity into the ambient flow outside of the cavity. The at least one flow partition comprise an inboard surface facing predominantly towards the cavity and an outboard surface facing predominantly away from the cavity. An aircraft comprising the cavity system is also provided.

Abstract: A cavity system (300-600) is provided. The cavity system comprises a cavity (2) and a spoiler (304-604). The spoiler (304-604) comprises at least one plate (4) having a front surface and a rear surface, and an undulating edge. The spoiler (304-604) is positioned in the proximity of a leading edge (14) of the cavity (2), the leading edge (14) being relative to an actual or intended flow direction (3) of a fluid over the cavity (2), and the spoiler (304-604) is arranged with its longitudinal axis (1) perpendicular to or at an oblique angle to the actual or intended flow direction (3) such that the front surface faces towards the flow direction (3).

Abstract: A cavity system for use on a vehicle is provided. The cavity system comprises a cavity having at least one of a front edge and a rear edge arranged orthogonally to the actual or intended direction of travel of the vehicle, and longitudinal edges. The front and/or rear and longitudinal edges define an opening. The cavity system also comprises at least one shock stabiliser protruding from a surface adjacent each longitudinal edge of the cavity into the ambient flow outside of the cavity. An aircraft comprising the cavity system is also provided.

Abstract: A rake assembly for measuring fluid flow parameters in a fluid flow rig, comprises: a rake assembly support frame; a housing mounted on the rake assembly support frame; the housing comprising a wall which defines a flow passage, with a flow inlet and a flow outlet, the flow passage extending from the flow inlet to the flow outlet. The housing is cylindrical and is centred on a longitudinal axis. An instrumentation arm extends from a leading edge end to a trailing edge end, and the instrumentation arm extends from the housing wall to extend at least part of the way across the flow passage, the leading edge end located in an Aerodynamic Instrument Plane (AIP); the housing being rotatably mounted to the rake assembly support frame; such that the housing and instrumentation arm are operable to rotate at least part of the way around the longitudinal axis.

Abstract: There is provided a sacrificial sensor configured to be coupled with a part and provide an indication of damage in the part, wherein an electrical property of the sacrificial sensor is configured to change as the sacrificial sensor is damaged to indicate damage to the part.

Abstract: There is described a reconfigurable array for facilitating dynamic combination and distribution of RF signals.

Abstract: A optical apparatus to display an image to a user is disclosed. The apparatus comprises an image source to generate an image bearing light beam having a first numerical aperture; and a diffuser screen. The diffuser screen is configured to increase the numerical aperture of the image bearing light beam to a second numerical aperture. The diffuser screen comprises a first part comprising: a first face and second face substantially parallel to each other, a first array of a plurality of waveguides forming an optical path between the first face and the second face. A value of an optical property of each of the plurality of waveguides is selected randomly from a set of values of the optical property. The first array of a plurality of waveguides is arranged such that each of the plurality of waveguides has an optical axis that is substantially parallel to it's nearest neighbour.

Abstract: An image generation system and method for displaying an Augmented Reality “AR” image of a real-world environment having one of more objects located therein and one or more AR objects each corresponding to a respective object, the system comprising: a display on which the image of the real-world environment and the AR objects are displayed; a processing and control module configured to: receive, from one or more sensors, data relating to the real-world environment and objects therein; create the one or more AR objects from the objects by determining additional information relating to the object which is represented by at least one of symbols, annotations and fonts to be attached to the AR object to act as a displayed component: displaying the AR image comprising the real-world image and one or more AR objects; wherein the AR objects once created are stored for future retrieval based on a unique identifier for the AR object which remains active as long as the object is of interest.

Abstract: A heat engine system comprises a compressor, a heat source, and a turbine, each having an inlet and an outlet, and which collectively define part of a working fluid flow circuit. The system further comprises a housing operable to be sealed to define a reservoir in which the compressor, heat source, and turbine are located. The working fluid flow circuit further comprises a compressor-to-heat-source duct which extends between the compressor outlet and the heat source inlet, a heat-source-to-turbine duct which extends between the heat source outlet and the turbine inlet, and a turbine-to-compressor duct which extends between the turbine outlet and the compressor inlet. A bleed valve is provided in flow communication with the compressor outlet, operable to bleed working fluid into the reservoir. An intake valve is provided in flow communication with the compressor inlet operable to allow passage of working fluid from the reservoir to the compressor inlet.

Abstract: According to the present disclosure there is provided a duct arrangement for influencing fluid flow, the duct arrangement comprising: a duct section arranged to receive a fluid flow therethrough, the duct section defining a first direction through the duct section from a fluid inlet end to a fluid outlet end; a rotor housed in the duct section, the rotor comprising one or more rotor blades; and a vortex generator surface housed in the duct section, the vortex generator surface arranged to induce vortices in the fluid flow through the duct section.

Abstract: A router node comprises a link discovery module, a security module, a secure access module and storage. The link discovery module discovers a link to an adjacent router node and receives its first loopback address. The link discovery module creates a first tunnel between the security module in the router node and the first loopback address. The security module receives a second loopback address for the second router node, and creates a second tunnel. The security module repeats the discovering, receiving and creating steps for each router node adjacent to the first router node. The storage separately stores a link discovery routing table which comprises information relating to the links between the router node and each adjacent router note; a security routing table which stores the unique first loopback address; and a secure access routing table which stores the unique second loopback address.

Abstract: A Laser Designator Pod (LDP) protective system, the LDP protective system comprising: a protective hood a laser detector arranged within the protective hood to generate a signal when exposed to laser radiation within a predefined range of wavelengths; and a computing device to record the generated signal.

Abstract: An electroacoustic transducer array 110 is described. The electroacoustic transducer array 110 comprises a first electroacoustic transducer 40A comprising a first active element 41A and a second electroacoustic transducer 40B comprising a second active element 41B. The electroacoustic transducer array 110 comprises an acoustic coupling layer 43 arranged to acoustically couple, in use, the first active element 41A and the second active element 41B to a transmission medium. The electroacoustic transducer array 110 comprises a first cavity 42A arranged between the first active element 41A and the acoustic coupling layer 43 to receive a first fluid; and/or a second cavity 42B arranged between the second active element 41B and the acoustic coupling layer 43 to receive a second fluid. In this way, acoustic coupling of the electroacoustic transducer array 110 and the transmission medium is improved.

Abstract: According to an aspect of the invention, there is provided a fuze arming system for a munition, comprising: an arming circuit arranged to detect a setback event and, in response to the setback event, generate a signal indicating that an arming event has occurred, wherein the arming circuit comprises a sensor configured to produce a graduated output when the setback event occurs, and fuze arming system is arranged to use that graduated output.

Abstract: A head mounted display system for use on a watercraft is disclosed. The head mounted display system comprises circuitry to determine orientation information of a head mounted display system relative to the watercraft and a display configured to superimpose graphical information over objects in a field of view of at least one eye of a user of the head mounted display system. The graphical information is based on sensor data and the orientation information of the head mounted display. The sensor data is provided by at least one data source associated with the watercraft.

Abstract: This invention relates to a parachute sea anchor system deployable from a payload tube. There is provided a parachute sea anchor system suitable for launch from a vessel comprising at least one payload tube, said payload tube, comprising a payload canister, which comprises a parachute sea anchor, wherein said parachute sea anchor comprises a buoy tethered thereto, wherein said payload canister is attached to said vessel.

Abstract: A blast attenuation device for a gun tube. The blast attenuation device has a first wall section which defines a first chamber, which extends from an inlet end having an inlet aperture to an outlet end having an outlet aperture. The blast attenuation device also has a second wall section which defines a second chamber, which extends from an inlet end having an inlet aperture to an outlet end having an outlet aperture.

Abstract: A signal transmitting device is provided for communicating with an aircraft in the vicinity of a landing area. The signal transmitting device is configured to receive a signal from the aircraft and further configured to transmit a return signal to the aircraft automatically upon receipt of the signal. The return signal comprises information regarding the landing area.

Abstract: An arrangement for influencing liquid flow comprises a first section selectively configurable to provide a vortex generator surface to induce vortices in the liquid flow. The arrangement further comprises a second section, wherein the first section and second section are movable relative to one another to provide the vortex generator surface.