Abstract: A wind turbine comprising a support structure and one or more turbine blades is disclosed, that incorporates means for reducing the radar cross section (RCS), wherein the support structure is notionally divided into an upper section in the shadow of the blade sweep area, and a lower section beneath the upper section, wherein the upper section is adapted to have the means for reducing the RCS, and the lower section does not have the said adaptation. The invention makes use of the realization that the blade masking the tower as it rotates (or the blade being masked by the tower if facing away from a radar), contributes significantly to interference to radar systems, and so localized application of e.g. RAM can give good RCS reduction at a lower cost than treating the whole structure.

Abstract: A drone detection radar can include a plurality of antenna systems, each antenna system being arranged to transmit a signal into an associated sector, and to receive signals reflected from targets in the sector, the sectors collectively forming a monitored volume, and wherein a sub-set of the antenna systems are active at any one time, with the active sub-set of antenna systems being arranged to monitor their respective volumes for a duration sufficient to measure Doppler signals associated with slow moving drones, with the radar being arranged to switch to a different sub-set of antenna systems after each duration, such that the whole volume is monitored within a predetermined period. Combining a staring array from an antenna system with a plurality of switched antenna system allows drones to be both detected and tracked, with appropriate selection of the predetermined period.

Abstract: The present invention discloses a detection device for discriminating between different materials, and a method for doing so. The device comprises an optical system having at least one optical focussing element and a receiving element. The receiving element is sensitive to electromagnetic radiation, typically in the millimeter wave band, and the optical system being arranged to focus incident energy from a scene onto the receiving element. The optical system comprises a prism element having a first surface and a second surface, the first surface being opposite the second surface. At least a portion of the first surface is positioned at an angle ? to the second surface. The angle ? varies between a minimum at a first position on the first surface and a maximum at a second position on the first surface.

Abstract: A drive member selection mechanism is described, including at least one drive member and at least two selector members, wherein the drive member includes a first and second face, and further includes, on each face, at least one projection, and the selector members include, on at least one face thereof, at least one complementary projection arranged to selectively engage with a projection of a drive member, the arrangement being such that the projection(s) of a selector member and the projection(s) of the first face of a drive member may be drivingly engaged in a first torque connection and the projection(s) of a selector member and the projection(s) of the second face of a drive member may be drivingly engaged in a second torque connection, wherein the second torque connection is opposed to the first torque connection.

Abstract: Methods and apparatus for determining a data signal. In an example, a method includes acquiring at least one image of a field of view at a first frame rate and identifying a sub-region of the field of view, wherein the sub-region contains an optical data signal. A plurality of images of the sub-region of the field of view may be acquired at a second frame rate, wherein the second frame rate is higher than the first frame rate, and a data signal encoded in the optical data signal may be determined from the plurality of images of the sub-region of the field of view.

Abstract: A shifting apparatus including a shaft extending along an axis, and at least one shifting feature, each of the at least one shifting feature including: a multi-part pin having first and second parts arranged to rotate relative to each other that extend through respective slots extending along the shaft; a drum arranged around the shaft and having channels extending along the length thereof wherein the first and second parts of the multi-part pin are respectively received for enabling torque transfer to the drum when the shaft is rotated, the drum also defining a track at least partially around its outer surface; a biasing mechanism for urging the drum towards a rest position along the length of the shaft; and a drive member selector member provided in operative relation to the track. The drive member selector member can be controlled to selectively engage a drive member.

Abstract: A method for the reception of a frequency hopped direct sequence spread spectrum signal includes acquiring the signal by splitting the received signal into a plurality of processing sub-channels, each corresponding to one or more hop frequencies; and within each sub-channel: i) subtracting any sub-carrier frequency from the received signal; ii) filtering the signal from (i) using a chip-matched filter; iii) selecting a sub-set of samples from the filtered signal; iv) correlating the sampled signal from step (iii) with a known reference signal to produce at least one correlator output. The output(s) from each sub-channel are provided to an input of a corresponding one or more common discrete time Fourier transforms (DTFT), and an output therefrom having a peak above a predetermined threshold is selected for further processing in the receiver. The method is a less expensive way of tracking the signal and can demodulate appropriately modulated signals.

Abstract: Some embodiments are directed to an electric motor that includes a stator including a plurality of circumferentially distributed drive elements for causing an electromagnetic driving force to be applied to a rotor of the electric motor in use. Each drive element includes a wire extending around a metal core to define a plurality of coils for magnetizing the metal core when current flows in the coils. At least one space exists between the metal core of each respective drive element and the coils around it. A cooling device is provided for transferring heat away from the drive elements. Each drive element further includes a heat conductor including a plurality of mutually electrically isolated metallic elements located in the or each respective space between the metal core thereof and the coils around it, for transferring heat from the coils to the cooling device.

Abstract: A system for compensating for phase noise, with particular application in lidar, includes a compensation interferometer that receives a signal from a source, and splits it into a first and second path, with a path length difference ?? between them. Typically the path length is significantly less than that of the return distance to a target. The output of the compensation interferometer, which consists of phase noise generated in time ?? is vectorially summed during a time similar to a signal flight time to a target, and the result used to reduce phase noise present on measurements of a target. It further includes means for selecting ?? such that competing noise elements are reduced or optimised.

Abstract: A system and method of using the same, wherein the system comprises: an optical surface having a diffractive image generating structure disposed thereon, the diffractive image generating structure itself comprising a layer of reflective material incorporating a plurality of grooved diffractive elements each having a periodic wave surface profile, the periodic wave surface profiles each having a groove alignment direction; a source of incident electromagnetic radiation arranged to illuminate the diffractive elements at an angle of incidence substantially normal to the plane of the surface of the diffractive elements; means for polarizing the radiation from the source, and means for polarizing radiation reflected from the diffractive elements; wherein the diffractive elements are configured such that, in use, polarization conversion of the incident radiation takes place, and wherein the diffractive elements are disposed in a two dimensional array of pixels to represent an image; and further wherein the means fo

Abstract: A method of tracking a plurality of signals from a single satellite comprises receiving a first signal transmitted by a satellite; receiving at least a second signal transmitted by the same satellite; applying a pre-filtering process to determine the cumulative in-phase and quadrature components of the first, second signals, and optionally any further signals; and applying a filtering process to the cumulated in-phase and quadrature components of the first and at least second signals to determine a range and range rate of the satellite; wherein the filtering process comprises applying a Kalman filter. The method results in a determination of the range and range rate from a single satellite with improved signal to noise ratio. The range and range rate so determined may be used, with data from other satellites, to produce a navigational position. The method may be used with each such satellite used in producing the navigational position.

Abstract: A celestial navigation system includes an optical device for receiving light from a celestial object, a spectrometer for measuring a spectrum of the light in sufficient detail to identify absorption and/or emission features, and a processor for processing the spectrum to match the spectrum, or a processed version thereof, against a set of reference spectra information in a database, a device for measuring the pointing direction of the optical device and a clock. The matching may be on a maximum likelihood basis. The system is thus able, on identification of a single star, and, using commonly available navigational almanacs, to calculate a geographical position. Celestial navigation takes place even when only one celestial object (that is also within the database) is visible, although improved accuracy may be obtained with multiple observations. Advantageously, the database includes stars of the K and/or M type, that have more characteristic spectral content.

Abstract: Some embodiments are directed to an apparatus for managing fluid flow in a vehicle, that includes an epicyclic gear set having first, and second inputs configured to receive rotational drive input from a torque output feature of a powertrain and a rotary actuator respectively. A pump driver is provided for driving a fluid pump, the pump driver being configured to receive rotational drive input from an output of the epicyclic gear set. A controller is configured to determine information corresponding to the rotational speed of the torque output feature using information generated by a rotational speed sensor and based on this control the rotary actuator, such that the pump driver is caused to rotate at substantially a pre-specified speed.

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: An electronic hardware assembly including at least a first and second laminar component, wherein the first laminar components includes a die, the die including a substrate, a functional region and a first protective layer, and the second laminar component includes a second protective layer, wherein the first and second laminar components are arranged in a stack such that the functional region of the first laminar component is arranged within the assembly substantially between first and second protective layers.

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.