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Salisbury, United Kingdom

Butters B.,Chemring Countermeasures Ltd
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

Imaging seekers used in modern Anti Ship Missiles (ASMs) use a variety of counter countermeasure (CCM) techniques including guard gates and aspect ratio assessment in order to counter the use of IR decoys. In order to improve the performance of EO/IR countermeasures it is necessary to accurately configure and place the decoys using a launcher that is trainable in azimuth and elevation. Control of the launcher, decoy firing times and burst sequences requires the development of algorithms based on multi-dimensional solvers. The modelling and simulation used to derive the launcher algorithms is described including the countermeasure, threat, launcher and ship models. The launcher model incorporates realistic azimuth and elevation rates with limits on azimuth and elevation arcs of fire. A Navier Stokes based model of the IR decoy includes thermal buoyancy, cooling of the IR smoke and its extinction properties. All of these factors affect the developing size, shape and radiance of the decoy. The hot smoke also influences the performance of any co-located chaff or other obscurant material. Typical simulations are described against generic imaging ASM seekers using shape discrimination or a guard gate. © 2011 SPIE. Source

Smith L.,Cranfield University | Richardson M.,Cranfield University | Walmsley R.,Chemring Countermeasures Ltd
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

The ultraviolet (UV) band of the electromagnetic spectrum has potential as a host medium for the operation of guided weapons. Unlike in the infrared (IR), a target which is propelled by an air breathing jet engine generates no detectable radiation in the UV band, and is opaque to the background UV produced by the Sun. In theory the blocking of UV radiation from the sun causes a detectable 'negative contrast' between the target and the background. In order to determine the outcome of engagement scenarios between airborne platforms and guided weapon systems that utilise a guard channel operating in the UV, it is necessary to accurately model background UV levels. This paper presents a comparison between the atmospheric modelling code moderate resolution atmospheric transmission (MODTRAN®5) and measured data. The spectral irradiance levels generated by the MODTRAN®5 code are compared to those of the World Ozone and Ultraviolet Data Centre (WOUDC ) database, for various global positions and times of year. Radiance data collected at the Defence Academy of the United Kingdom (Shrivenham, England) for various observer geometries is also compared to that generated by the MODTRAN®5 code. © 2013 SPIE. Source

Chemring Countermeasures Ltd | Date: 2013-05-07

decoy missile launchers.


A process of producing an infrared radiation-generating decoy for protecting against heat-seeking missiles and other heat-seeking devices comprises the step of decomposing a metal carboxy compound in the substantial absence of gaseous oxygen, to produce a pyrophoric material as a decomposition product of the metal carboxy compound, which pyrophoric material is arranged to combust spontaneously upon contact with air when the decoy is used. The metal carboxy compound may be iron oxalate, and the pyrophoric material may be ferrous oxide. The pyrophoric material may be coated onto a substrate, and a plurality of coated substrate pieces may be used in a decoy.

Birchenall R.P.,Defence Academy of the United Kingdom | Richardson M.A.,Defence Academy of the United Kingdon | Brian B.,Chemring Countermeasures Ltd | Roy W.,Chemring Countermeasures Ltd
Infrared Physics and Technology | Year: 2010

The global proliferation of shoulder launched IR Man Portable Air Defence Systems (ManPADS) has resulted in the existence of a serious threat to both civilian and military aircraft from terrorist attack. Some of the older generations of ManPADS can be defeated with modern countermeasures but even the most sophisticated protection still has vulnerabilities to the latest family of ManPADS. This paper describes the work undertaken by the authors to model a second generation ManPAD, based on the Russian SA-14, and assess the vulnerabilities of aircraft both with and without flare countermeasures from these systems. The conclusions are the results of over 11,000 simulated firings against targets of varying aspects, velocities and altitudes. © 2010 Elsevier B.V. All rights reserved. Source

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