David J. Purdy
In the design of Weapon Control Systems (WCS) for main battle tanks there is a requirement for low-order models of the elevating mass and barrel. In this work two models suitable for this requirement are put forward. The two models under consideration break the barrel down into rigid sections that are connected by frictionless pin-joints and linked by torsional springs and dampers. This model is referred to as a Lumped Parameter Flexible Beam Model (LPFBM) in this work. These models consider the barrel being broken down into two and three rigid sections. The lengths of the rigid sections and spring stiffnesses are selected to preserve the resonances (poles) and anti-resonances (zeros) of the system. This is achieved by using a novel scheme based on equations derived for the cantilever mode frequencies for the zeros and on optimising the lengths of the rigid sections for the poles. The responses from these two models, in the frequency and time domain, are compared to a finite-element barrel version, which is used as the base model and a non-optimised two-section LPFBM. Recommendations are then made on the appropriate model to use in the design of a WCS based on the required frequency range of the model and whether muzzle motion predictions are needed.
Joanna Szmelter and David Leeming
This study was designed to determine the extent to which aerodynamic interactions affect the pellet pattern from shotguns as this has considerable influence on their impact. After the characteristic separation of pellets was obtained from their probability densities, the detailed flow field was obtained using Computational Fluid Dynamics (CFD) analysis. The reported initial results illustrate the influence that the wake of preceding pellets has on the trajectory of trailing pellets.
Alfred Kaufman
This paper explores the strategic consequences of networking a military force under the assumption that such networking would deliver the combat power increases claimed for them by the Network Centric Warfare doctrine. Because of the large difference in combat power likely to exist under this assumption between networked and non-networked forces, such an exploration requires non-linear models of war in which the protagonists adapt their behaviour to the vagaries of the ongoing battle. We show that even the simplest model able to account for adaptation displays the ability of a networked force to terminate the combat phase of war in relatively short order, but find that termination of combat does not lead to victory unless the surviving enemy force is rendered inert by other means than combat.
Anthony H. Dekker
Like other militaries, the Australian Defence Force (ADF) is committed to producing a more agile force in the next two decades. As the Enabling Future War Fighting: Network Centric Warfare document [1] states:
Mubarak Al-Jaberi, Mark Richardson, John Coath, and Robin Jenkin
Laser-assisted weapons, such as laser-guided bombs, laser-guided missiles and laser beamriding missiles pose a significant threat to military assets in the modern battlefield. Laser beamriding missiles are particularly hard to detect because they use low power lasers. They are even harder to defeat because current countermeasures are not designed to work against this threat [1]. The aim of this project is to examine the vulnerability of laser warning systems to guided weapons, to build an evaluation tool for laser warning receivers (LWRs) and seekers, and try to find suitable countermeasures for laser beamriding missiles that use low power lasers in their guidance systems. The project comes about because of the unexpected results obtained from extensive field trails carried out on various LWRs in the United Arab Emirates desert, where severe weather conditions may be experienced. In order to approach the subject, a computer model has been developed to enable the assessment of all phases of a laser warning receiver and missile seeker. MATLAB & SIMULINK software have been used to build the model. During this process experimentation and field trials have been carried out to verify the reliability of the model. This project enables both the evaluation and design of any generic laser warning receiver or missile seeker and specific systems if various parameters are known. Moreover, this model will be used as a guide to the development of reliable countermeasures for laser beamriding missiles. This paper (Part I of a four-part series of papers) outlines the theory required to construct a computer model for a laser beamriding missile engagement.
Amanda Jane Brosnan
Bayes’ Theory of conditional probability and efficient algorithms for probability computation together allow a probabilistic approach to expert systems known as Bayesian Belief Networks (BBNs). BBNs facilitate the graphical representation of complex problems and allow users to make expert predictions on the likelihood of a hypothesis in the absence of complete information. As such they seem applicable to the problem solving in the face of uncertainty that characterises enemy course of action (COA) assessment at the tactical level of war. In this paper, BBNs were constructed to reflect two distinct tactical intelligence problems, one based on conventional operations, and one based on peace support operations (PSO). Difficulties were encountered in quantifying the PSO BBN because the intelligence collection plan reflected a requirement to collect information on enemy capabilities as well as intent. Consequently, the BBN had to be modified. Overall, however, it was found that BBNs could be constructed to reflect the tactical enemy COA assessment problem. Nevertheless, it was found that the utility of such BBNs was limited, especially in the conventional environment, because of the likely requirement to modify quantification to reflect actual battlefield factors such as weather and terrain, even for the same set of COA. It was considered that the development of a library of BBN fragments prior to deployment could go some way to alleviate the problem, although mainly in the PSO environment with a slower operational tempo. On the other hand, the modification problem could be solved by making the BBN more general, allowing it to be used as a tactical indicator and warning tool, at least in the PSO environment.
