Cranfield Defence and Security
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Browsing Cranfield Defence and Security by Type "Working Paper"
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Item Open Access An Evaluation of Sensor and Data Fusion Technologies for Application within an Integrated Base Defence System(2009-11-11T17:45:23Z) Tsourdos, Antonios; Silson, P.; White, B.; Spillings, J.; Burke, P.The purpose of this paper is to communicate the technical issues involved in integrating data fusion technologies in the development of an integrated base defence system. Options are presented, with possible alternatives, when selecting the sensor systems to support specific mission goals. The document then provides a proposed candidate system architecture that integrates the independent systems to support the commander’s information needs.Item Open Access Experimental and Computational Investigation of an “Open” Transonic Cavity Flow(2009-11-10T18:31:10Z) Atvars, K.; Knowles, Kevin; Ritchie, S. A.; Lawson, Nicholas J.This paper presents an investigation of a transonic flow (M∞ = 0.85) over a rectangular cavity having a length-to-depth ratio of 5. Velocities were measured inside the cavity on the central plane and two off-centre planes using a two-component particle image velocimetry system. These measurements were supported by surface flow visualisation, and mean and time-varying surface pressure measurements. The flow was also simulated using an unsteady Reynolds-averaged Navier Stokes code, with a realizable κ− ε turbulence model. It is shown that this CFD model does not capture all the characteristics of the flow field correctly. However, by using this integrated experimental and computational approach we have been able to identify three-dimensional flow field structures within the cavity. The influence of the thickness of the approaching boundary layer is discussed.Item Open Access Merging probabilistic data of multiple targets detected by multiple sensors(2009-11-11T17:54:28Z) Spillings, J.; Tsourdos, Antonios; Silson, P.; White, B.The aim of this work is to present an extension to current data fusion techniques and associated results for the implementation of a collaborative multi-platform, multi-target detection system. A multi-sighting data fusion algorithm has been simulated. The groundbased platforms have been assumed autonomous, with fully operational guidance systems. The attached sensors have associated errors that are controlled through the simulation. The target sightings and errors are translated into estimates with associated covariances in both the major and minor axes represented by 3-dimensional Gaussian distributions. Data merging is performed in two stages using the Jointly Gaussian Probability Density Function (JGPDF) with global alignment and minimal acceptable distance calculations. Empirically data highlights that, when using this approach a better estimate of the target’s location can be obtained when more observations are made, along with distinguishing between multiple targets. This paper aims to explore the issues surrounding localising detected targets within a know region from data gathered by multiple platforms. The problem is addressed by using a platform, having a known map to perform self-localisation, to detect and localise a target with respect to itself. The technique of interest for localisation is Simultaneous Localisation and Map building (SLAM) while research will be conducted into data fusion techniques for merging of the resulting target acquisition data. The main objectives of this work are to: - gain a theoretical understanding of SLAM and the surrounding issues, - compare and contrast the estimation techniques employed within SLAM, - perform a short study into appropriate sensor suites and fusion techniques and - develop a practically feasible solution to the described SLAM problem.