Simulation
Wednesday 10th November 2010, 0900hrs–1030hrs
Chaired by Jerry Bradshaw Integration between Main Ship Design Characteristics and Naval Task Effectiveness, during the Warship Acquisition Phase Mr Francesco Perra, Orizzonte Sistemi Navali SpA, Italy PART ONE:
The exploration of various design solutions for a new warship is a fundamental process for selecting the configuration and characteristics of the final ship that meets the operational requirements. Present practices for management of the initial phase of Concept Definition are based on experience, balanced application of project constraints, empirical rules and experimental information, and analytic insights into the many technologies that are a part of a modern warship. This knowledge is employed within a consolidated team of experts who balance requirements, constraints, and resources. Many elements of this process employ computers to support decisions and manage portions of the overall selection process. At present, consistent and effective practices for “assisted planning” (i.e., a methodology and an environment that supports the evaluation of operational effectiveness of a Naval Unit in relation to requirements and ship design characteristics) do not exist in an integrated form. To achieve sufficient capability in this area of design it is necessary to have a computer based system that establishes an explicit connection between naval architecture and naval operational analysis. The basic objective is the integration of different principal areas for analysis and design within one environment (framework). The principal areas are:
Measures of effectiveness for each naval task (Operational Evaluation Model);
Ship synthesis design for a naval vessel (Ship Synthesis Mode – SSM);
Multi-objective optimization;
Multi – criteria – Decision analysis. An exclusive case study of a small OPV will be presented with sprint speed in a range of 21 to 30 knots.
The resulting main ship characteristics as well as patrol task effectiveness are presented and analyzed. PART TWO:
In the current debate about Ship Design much emphasis is given to Early Stage phases of the process: in particular, concept definition and Rough Order of Magnitude (ROM) Design. During these phases, it is only possible to have a sketch of the possible ship to be further designed. At this level of the design in which an idea of area, weight and volume of the ship are available, it’s important to include an evaluation of the radar signature of the naval Unit. This paper will focus on RCS evaluation at level of concept design. Two main characteristics are required to a RCS evaluation in ESD: it should be based on first principles; high level of accurateness is not required, but the RCS evaluation should change properly as a function of the main characteristics of the ship (dimensions, top side design, …) The main characteristics of the present method are: the sketch of the ship is approximated by a mesh of flat surfaces; the ship is assumed to be made up of perfect electric conductors; the contribution to the scattered field of each flat surface is evaluated using asymptotic approximations, such as optical physics and diffraction theory; Gordon’s method is adopted and Ufimtsev’s theory is applied to account for border effects; contribution due to multiple reflections (only the first one is considered) are included by exploiting a ray-tracing-based approach. Anti Submarine Warfare Search Evaluation - Two Case Studies Mr. Aldo Guagnano, Orizzonte Sistemi Navali SpA, Italy Evaluation of Naval Task effectiveness is important non only for force and operational planning,
but also to support the acquisition phase of a Naval Unit. In this paper, two examples are shown
related MIO and ASW naval Task. First case : Analytical Evaluation of Maritime Interdiction Operation (MIO)
MIO is the task currently performed in almost all existing operations in which naval forces are
employed: peace keeping, peace enforcing, maritime border control, illegal immigrants, smugglers
control. In this case of study MIO is analysed and analytically formulated through QUEUEING THEORY
(BIRTH-DEATH models) and MARKOV CHAINS. Second case : Optimization of a ASW Naval Task using Design Of Experiment (DOE)
The threat of hostile submarines is increasing and the need for effective Anti Submarine Warfare
(ASW) operations is growing : in particular , it’s considered the case of ASW search following
‘Datum’. Resources employed could be Naval Surface Unit, MPA, Helo or UAV and the search activity is
normally conducted using an Archimede Spiral and the second case of study proposes a
methodology to estimate the recommended track spacing.
Design Of Experiment (DOE) and the methodology of Latin Hypercube are employed in order to
analyse the influence on task effectiveness (MOE) of input variables (sensor detection range, MPA
Speed, Threat speed etc..)
MAST timetable
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