Abstract:
A de-icing system for a hemispherical protective housing mounted on an aircraft structure is described. The system can include a series of piezo-electric devices mounted at the boundary of the housing. The piezo-electric devices generate ultrasonic frequencies and resonance of the protective housing is induced. One of the piezo-electric devices senses the frequency generated in the protective housing and acts as part of a feedback loop to maintain structural resonance of the protective housing. The structural resonance of the protective housing prevents the build-up of ice. Additionally, higher power resonances can be generated to remove ice already built up on the protective housing. The system also enables detection of ice build-up on the protective housing by monitoring any change in the frequency required to maintain structural resonance of the protective housing.
Abstract:
An exemplary laser system is disclosed which includes a pump laser diode array and laser gain material, in which the array generates optical radiation having a predetermined total linewidth approximately 20 nm wide constructed from a plurality of individual wavelengths with a linewidth of up to 8 nm, the center wavelength of radiation being for example within the absorption band of laser gain material used at the center point of the operating temperature of the array. The system can include a highly reflecting plane mirror with periodic transmitting patches placed between the laser diode array and the laser gain material, the size of the transmitting patches being such that minimal pump radiation is lost.
Abstract:
An Infra Red (IR) camera and method of operating the same is disclosed. The camera includes a detector having an infrared focal plane array (IRFPA). The camera is operated in such a fashion, implemented in software, to maximize the detector operating temperature under varying scene temperature and atmospheric conditions in order to achieve a predetermined and adequate level of sensitivity and operability from the detector.
Abstract:
A method of identifying and tracking a target is described, in which seismic data relating to a target is passively detected and processed using statistical means. The statistical manipulation of the data includes frequency information extraction, dynamical mixture model construction based on existing known data and identification of an unknown target by the convergence of this model to a state characteristic of that target.
Abstract:
A camera for polarimetric, multispectral imaging is described. Such cameras are used in photonics, computational imaging and multispectral imaging in which both multispectral and polarimetric sensing modalities are used simultaneously for detection, recognition and identification. The camera enables multiple spectral images to be recorded simultaneously using polarising beamsplitters and mirrors to divide the image according polarimetric and spectral bands. These multiple, polarised images are recorded on a single focal plane array (FPA) simultaneously. An image processor allows for the resolution of the subsequent image to be improved.
Abstract:
A radio frequency digital receiver system and method is described in which the radio frequency digital receiver system uses a discrete Fourier transform where detection decisions are made based on a spectral estimate. The spectral estimate is formed from an output of the, in which the spectral estimate is improved by enabling spatially variant apodization (SVA) such that the detection ability of the RF digital receiver is improved. In a further embodiment, the SVA is optimized for use with Digital Signal Processing.
Abstract:
An Infra Red detector system and method is disclosed. There is benefit in providing signal processing functions into each pixel of a 2D focal plane IR detector for applications such as hostile target detection. The thermal characteristics of muzzle flash or a projectile and it's trajectory for example are distinguishable from background scene. A technique to add a signal detection function to normal IR detector thermal imaging operation to a standard direct inject Integrate While Read (IWR) pixel circuit and for providing target detection at extremely high data rates is described.
Abstract:
Modern military aircraft are prime targets for surface to air and air to air RF guided missiles. Modern missile systems in particular are difficult to counter and have an array of Electronic Protection Measures at their disposal. Expendable Active Decoys provide effective protection for fast jet platforms by creating a realistic false target that seduces the missile away from the protected platform. They can be fitted to almost all military platforms as they are expended from standard chaff and flare dispensers. Simple repeater devices have been produced in the past but they lack the sophistication to defeat modern threats. Digital RF Memory based jammers have the necessary capability but have always been too large due to their complexity. A system architecture, design features and technologies are disclosed to reduce the size of a Digital RF Memory 12 based jammer to fit within a volume 0.5I.
Abstract:
A method of forming infra red detector arrays is described, starting with the manufacture of a wafer. The wafer is formed from a GaAs or GaAs/Si substrate having CMT deposited thereon by MOVPE. The CMT deposited can include a number of layers of differing composition, the composition being controlled during the MOVPE process and being dependent on the thickness of the layer deposited. A CdTe buffer layer can aid deposition of the CMT on the substrate. Once the wafer is formed, the buffer layer, an etch stop layer and any intervening layers can be etched away leaving a wafer suitable for further processing into an infra red detector.
Abstract:
A portable antenna with a housing in which the antenna is held when not in use, and a mechanism to cause the antenna to pop-up from, and sit on top of, the housing when it is to be used. The mechanism can function to collapse the antenna into the housing when not in use.