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QinetiQ, in association with Frazer-Nash Consultancy and Dstl, have developed a new numerical model of optical communications where part of the transmission is through water. The model (called Optical Communications Underwater Model or OCUM) finds the signal from air platform to sea platform (and vice versa) or between underwater platforms including the effects of scattering within the water, the refraction at the sea surface and transmission through cloud. The effects of scattering are found through Monte Carlo simulation before parameterizing the results to be used in subsequent calculations. The background light is also included from the sun to obtain the signal to noise ratio which is then used to find the analytical and numerical (via a message transmission simulation) bit error rate. This paper shows some of the details of the model and the approaches taken to obtain the transmission efficiency and performance. Some basic results will be presented to demonstrate the utility of the model.

A Naval Infrared Search and Track (IRST) demonstrator has been developed for the UK Ministry of Defence. The system uses two staring infrared cameras and split field of view optics to provide panoramic surveillance of the horizon and has real time processing for detection and tracking. The fusion of IRST and radar sensors offers an improvement in tracking due to their complementary nature. The benefit of integrating an IRST with other sensors has been assessed with simulated and real trials data. The high fidelity simulation begins with infrared scene rendering, followed by addition of targets, atmospheric effects, sensor characteristics and ends with plot extraction. This paper describes the simulation and compares the results with real data gathered with the IRST demonstrator.

A Naval Infrared Search and Track (IRST) demonstrator has been developed for the UK Ministry of Defence. The system uses two staring infrared cameras and split field of view optics to provide panoramic surveillance of the horizon. Use of staring detectors provides improved sensitivity and faster update rate than current scanning IRST systems. The demonstrator is fitted with commercial 640x512 pixel medium waveband detectors but is designed to accommodate 1024x768 pixel detectors in the future. The system features switchable spectral filters to allow choice of the optimum waveband for the prevailing environmental conditions and beam steering optics for non uniformity correction and image stabilisation. Real time processing has been implemented using a combination of Field Programmable Gate Array and PowerPC hardware for detection and tracking. The paper describes the system and presents some examples of its output.