Abstract: A method and system for purifying contaminated refrigerants is described. The refrigerant is heated in a controlled manner to separate it into fractions, one fraction having the pure refrigerant and the remaining fractions containing the contaminants. The temperature of the refrigerant fraction output being closely monitored and controlled to ensure that it is the correct required fraction.

Abstract: A system and method for calibrating an imaging system includes a shutter that is moveable in to the optical path of the imaging system to generate an image of the shutter surface, which is flat and uniform. The shutter can be moved in and out of the optical path between first and second positions. The shutter is heated whilst in the second position and then returned to the first position. Data sets generated at two different temperatures enable the image generated by the imaging system in normal use to be to be adjusted for responsivity and variation in DC offset of the specific pixel array.

Abstract: An infrared detector system is described in which a despeckle filter is applied to image data generated by a High Operating Temperature (HOT) detector array. The filter reads the data associated with each pixel of the image generated and compares it with selected neighboring pixels. The comparison yields a series of values that are compared to predetermined thresholds and the pixel is scored according to the number of values that exceed the threshold set. The score assigned to the pixel then determines the treatment of the pixel in the image to be generated. The data value of the pixel may be ignored, included or substituted with an alternative calculated value.

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 mechanism is disclosed to dismantle/erect a portable antenna that includes a linkage between radial driven elements and radial ground plane elements of the antenna which acts to cause them to move together between a collapsed and an erect arrangement.

Abstract: A method for preventing spatial or spectral beam seeding in a Q-switched laser is described. The Q-switch trigger of the laser is delayed by several laser resonator lifetimes after the end of the pump pulse. In this way, beam seeding is completely eliminated whilst pre-lase is maintained. The method described may be used for any laser system where the fall time of the pump radiation is sufficiently fast with respect to the upper state lifetime of the laser medium.

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: 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 radar system having side lobe blanking capability is disclosed. The system can include a single channel antenna and receiver system, the side lobe blanking system being time multiplexed, but requiring no dedicated guard channel data collection period such that the scan rate of the system is not degraded.

Abstract: An imaging device is described having an electro-mechanical image stabilization system capable of removing the effect on a generated image of vibration and angular movement of the device. The system includes a mechanical coupling interposed between the optics and the drive electronics of the device. The coupling ensures that movement generated by vibration is translated into linear movement of the optics and the drive electronics relative to each other.

Abstract: A portable antenna is disclosed that can be collapsed into, and erected from, a housing. There is also a pull cord mechanism arranged, when pulled, to cause the antenna to revert between the erect or collapsed configurations. The pull cord extends from the antenna to a position in easy reach of the soldier's hand so that the antenna can be erected/collapsed remotely.

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.

Abstract: Described herein is a method of generating a test program structure from test requirement data. The method comprises translating the test requirement data into a form suitable for execution within a test programming environment to generate a hierarchy of sequence files based on user supplied information. The test program comprises a plurality of Test Blocks and each Test Block comprises at least one Test.

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 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: A system and method of reducing undesirable image artifacts such as image tear and image smearing are described. The system can include a series of pixels and enhanced sensitivity circuits. The circuit can be configured so as to operate in an enhanced sensitivity mode having a combination of sample and hold circuits and binning functions, the combination acting so as to reduce the undesirable imaging artifacts.

Abstract: An Infra Red detector system and method are disclosed for a SAR ADC capable of operation at low power and for use on a Focal Plane Array FPA) detector. High power consumption makes known converter approaches unattractive for use on Focal Plane Array (FPA) detectors that are to be cooled to cryogenic temperatures. Many such ADCs are used on a FPA detector (e.g., up to one ADC per column of the imaging array) to digitize image data for the whole array at standard frame rates. Increased power makes cooling difficult to achieve or unattractive at system level. An exemplary system as disclosed can use an adaptive approach to set the comparator gain and settling time depending on the dynamics of the input signal, thereby achieving specified performance while reducing overall power.

Abstract: The present invention relates to an optical parametric oscillator. In particular, the present invention relates to a more optimal rotating image optical parametric oscillator. More specifically, there is described an optical parametric oscillator comprising six mirrored surfaces; wherein two of the mirrored surfaces are provided by a penta prism and the sequence of mirrors is operable to provide a predetermined rotation of a beam passing therethrough.

Abstract: A detector system is described in which an image of a scene is displaced with reference to a dual waveband detector array. Such ‘scanning’ increases the sampling density, thereby reducing the effective pixel pitch, by moving the image of the scene relative to the detector array by fractions of a pixel pitch in sequential frames. The display is then reconstructed with the data from these frames interleaved relative to the original scan displacement.