Abstract: A method of processing signal data including an unencrypted portion and an encrypted portion, the method including: receiving, at a receiver, the signal data; processing a sample of the signal data to provide a processed signal sample including data relating to the encrypted portion of the signal data and data relating to the unencrypted portion of the signal data, comparing the unencrypted signal data with at least one reference signal to determine information including at least one of (i) the time at which the signal was sent from the source and (ii) the identity of the source; requesting, based on the determined information, and from a source remote to the receiver, a set of encrypted reference signal samples; comparing, on a processing device remote to the receiver, the set of encrypted reference signal samples with the received encrypted signal data to identify any matching signal samples.

Abstract: Some embodiments are directed to an electromagnetic interference (EMI) indicator includes an ultra-wideband detector, preferably having a bandwidth of at least 30 MHz to 6 GHz. At least one antenna is provided for receiving EMI. Each antenna has receiver protection, a logarithmic receiver to convert the EMI signal into a direct voltage proportional to the magnitude of the EMI signal, a peak/average detector, and a controller connected to the output of the receiver for generating a signal when the direct voltage developed in the detector exceeds a pre-set threshold voltage using, for example, a carefully defined algorithm. The peak/average detector and controller are connectable to an indicator, which is activatable by the controller, which stores EMI event data in a non-volatile memory store.

Abstract: A thermally emissive apparatus (2) having an electro-thermal heating element (6) comprising a layer (8) of a first material having a first resistivity and a plurality of discrete regions (10) of a second material having a second resistivity substantially lower than that of the first material in electrical contact with the first material. The plurality of regions (10) of second material are arranged spatially so as to impart a predetermined effective sheet resistivity to the first layer (8). A plurality of heating elements may be used having a common first layer (30) of first material, wherein the spatial arrangement of the regions (10) of second material within a first heating element are optionally different to that within a second heating element. In this configuration the first and second heating elements may emit infrared radiation (14) having different intensities. The apparatus (2) finds applications as a thermal target and as an electro-thermal ice protection device.

Abstract: Some embodiments are directed to a multiplexed fiber sensor for a fiber optic hydrophone array, including a signal receiver configured to receive a signal from the fiber optic hydrophone sensor array and an interferometer. The interferometer is configured to produce a first signal component and a second signal component from the signal received from the hydrophone array, and also provided with a first polarization controller configured to control the polarization of the first signal component and a second polarization controller configured to control the polarization of the second signal component. A modulated carrier signal generator configured to generate a modulated carrier signal component based on the first signal component is also provided. A detector configured to output a demodulated output signal from the modulated signal component and the second signal component is included, wherein the modulated signal component and the second signal component output separately from the interferometer.

Abstract: Some embodiments are directed to a method of identifying a vehicle-borne transmitter emitting an interfering signal over a predefined frequency band. The method comprises monitoring the predefined frequency band at a first location to identify an emission of an interfering signal from a passing vehicle. If an interfering signal is detected, the method further comprises capturing a first image of the passing vehicle to enable an identity of the passing vehicle to be determined.

Abstract: A processor for a radio receiver is adapted to process direct sequence spread spectrum (DS-SS signals), and includes a demodulator, digitizer, correlator, and chip-matched filter (CMF) wherein the digitizer sample rate is selected to take a plurality of samples of each incoming chip at differing points thereon compared to sample points on an adjacent chip and to sample the chip at a non-integer multiple of the chip rate, wherein the CMF is arranged to filter the output of the digitizer. A sample selection unit is arranged to select a single sample from the CMF for input to each tap of the correlator, the selected sample being chosen as that nearest in time to a desired ideal time in relation to a timing reference point on the chip. An improved correlation function results, leading to better tracking performance.

Abstract: The invention relates to a thermal infrared transparent polymer film suitable for use in an identification device, said film comprising an infrared transparent polymer matrix with a pigment dispersed therein, wherein the thickness of the polymer film is greater than 30 micron and wherein the polymer film has an average transmission in the thermal infrared of greater than or equal to 0.5. Preferably, the pigment comprises an inorganic material. There is further provided a thin film, thermally reflective material (20) comprising the afore-mentioned infrared transparent film (21) and an infrared reflective layer provided on one surface thereof (22).

Abstract: Some embodiments are directed to a controlled differential adapted to couple two shafts and steer input, such as those provided in a drive configuration for a skid steered vehicle, the controlled differential including a pair of planet carriers arranged to turn with respective shafts; a pair of ring gears interconnected by a cross-shaft such that the ring gears rotate in common; planet gears and a pair of sun gears, the sun gears being coupled to at least one steer motor to enable rotation of the sun gears in mutually opposite senses upon input from the steer motor.

Abstract: Some embodiments are directed to methods of detecting a target that include: receiving signals reflected from a target of interest, the signals having a bandwidth large enough to provide a plurality of range cells along an expected target, and processing the received signal(s) by (i) determining the phases of contiguous groups of range cells, the group size selected to approximate to sizes of targets of interest, (ii) phase-shifting the returns within a group to increase constructive interference and thereby signal power; and (iii) combining the phase shifted returns to produce phase-adjusted combined returns, and performing a detection on those combined returns. Some embodiments may provide enhanced target detection capabilities. The process may be repeated for different potential target sizes, and may be performed either on real time data, or off-line on recorded data, and is applicable to both radar and sonar.

Abstract: A one-way valve for use in the inhalation and/or exhalation flowpath of respiratory protection equipment comprises a housing 1 defining a conduit and a circumferential array of three flexible flaps 2 each extending inwards from the conduit wall and in the direction away from the inlet end I of the valve. Under a pressure differential in the opening direction of the valve each flap is adapted to flex outwards towards the conduit wall and under a reverse pressure differential the free edge 5,5 of each flap is adapted to press in sealing contact with respective portions of the free edges of the neighboring flaps.

Abstract: This invention relates to a novel curing method of oligomers, using metal triflates, and particularly to the curing of hydroxyl terminated elastomers to achieve crosslinked polymers. The method finds particular use as an alternative cure methodology to replace isocyanate curing. There is further provided a cured and crosslinked polymer binder, which is particularly suitable and compatible for use with energetic materials.

Abstract: This invention relates to the field of an electromagnetic (EM) field absorbing composition, in particular, those capable of providing absorbance in the frequency of commercial radar. The composition finds particular use as a radar absorbing coating for wind turbines, in particular for use in onshore and offshore environments. There are further provided coated surfaces comprising the composition, methods of absorbing EM radiation, and methods of use of such a composition, such that a surface coated in the composition is capable of absorbing EM radiation. There is provided an electromagnetic radiation absorbing composition comprising elongate carbon elements with an average longest dimension in the range of 50 to 1 000 microns, with a thickness in the range of 1 to 15 microns and present in the range of from 0.5 to 20 volume % dried, in a non conductive binder.

Abstract: An electrothermal heater mat for anti-icing or de-icing of a helicopter rotor blade or other aerodynamic surface comprises a substrate, such as a flexible polyimide sheet, bearing tracks of a material of selected electrical resistivity, these tracks being formed by printing onto the substrate with a thermosetting ink loaded with electrically conductive (e.g. carbon) particles. Electrical bus bars/terminals for the supply of electrical energy to the resistive tracks may also be printed, using an ink loaded with particles of higher conductivity material such as copper or silver.

Abstract: A filter for removing coherent radiation from a source in a field of view, substantially independent of the size of the source, comprises a first reticle 22 located in the path of received light 21, a first lens 23 producing an optical transform of the first reticle 22 at a second reticle 24 located in the image plane of the first lens 23, a second lens 25 producing an optical transform of the second reticle 24 and a third reticle 26 located in the image plane of the second lens 25. The arrangement is such that the spatial transmittance of the third reticle 26 is selected to block at least part of the diffracted image of the first reticle 22 produced in the image plane of the second lens 25 and characteristic of the coherent radiation. Preferably the optical transforms are Fourier Transforms. A monochromatic coherent source in the field of view produces a pattern of diffracted energy in the image plane of the second lens which is independent of the size of the source.

Abstract: Some embodiments are directed to a gearbox including first and second rotational members, the first rotational member having a shaft portion extending away from the gearbox, the first rotational member carrying one or more projections, the second rotational member carrying one or more complementary projections, the projections carried by the first rotational member being configured to be drivingly engaged with the complementary projections carried by the second rotational member to transmit torque in a first torque connection but not in a torque connection that is opposed to the first torque connection. The gearbox further includes a one way clutch adapted such that the first and second rotational members can be drivingly engaged to transmit torque in a second torque connection, wherein the second torque connection is opposed to the first torque connection.

Abstract: A terrain disruption device includes an air or gas flow generation device mounted on a remote operated vehicle having an extendible arm, wherein the air or gas flow generation device includes an elongate (optionally detachable) ducting arrangement to direct the air or gas flow and an optional nozzle. The air or gas flow generation device and/or the elongate ducting arrangement may be mounted on the extendible arm. Preferably, the air or gas flow generation device is powered by a fan, more preferably an electric ducted fan.

Abstract: A respirator has one or more electrodes of e.g. conductive elastomer disposed on the surface of a face sealing member opposite to the surface which seals against the user's face. In use the integrity of the seal formed between the sealing member and the user's face is monitored by monitoring the electrical capacitance across that member between the electrode(s) and the user's face.

Abstract: A method for mitigating interference in a receiver, where the received signal is transmitted in a fashion having equivalent information content in at least two distinct bands. The method compares mean power per unit bandwidth in suitably normalised sidebands and sets a rejection threshold based upon the measured levels. Bands above the threshold may be rejected from further processing. The bands may include sidebands produced by a modulation process that produces sidebands having the same informational content. The threshold may be set relative to the band having the lowest mean power per unit bandwidth or according to some other function of the bands. Also extends to a signal processor in a receiver, and a receiver. The primary focus of the application is toward the Galileo Public Regulated Service (PRS) Satellite navigation signal.

Abstract: A shaped charge includes an explosive charge having a cavity lined with a laminate liner, the laminate liner comprising a primary liner located adjacent the cavity which forms a non-jet penetrator on detonation, and one or more supplementary liners each of which is less dense than the adjacent liner nearer the cavity. On detonation the liners form a series of penetrators, those formed by the supplementary liners acting to clear a path through an obstruction in front of a target to produce a more efficient attack on the target by that formed by the primary liner.

Abstract: Methods and apparatus for quantum key distribution are described, in particular including methods and networks 300 arranged to improve and/or ensure the security of data transmitted thereby by (i) ensuring a certain level of loss within at least part of the network, (ii) placing a penultimate and an endpoint nodes in situated in a secure second enclave, (iii) analyzing a transmitted bit stream to ensure that it does not provide an unacceptable amount of information about the key that may be generated therefrom, and/or (iv) varying the order in which bits are used to generate a key.