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Advisor(s)
Abstract(s)
A partir da base de dados WOD (World Oceanographic Database) de 2013 da NOAA (National Oceanographic and Atmospheric Administration) e das funções da toolbox GSW (Gibbs- SeaWater) encontrou-se forma, através da ferramenta de linguagem MATLAB, de calcular perfis de temperatura conservativa e salinidade absoluta ao longo da coluna de água. Dos perfis resultantes são calculados os perfis de densidade e velocidade do som. O software desenvolvido utiliza o perfil de velocidades do som para resolver a propagação do som em qualquer posição da base de dados WOD2013 através do método de raytracing.
A investigação feita na área de acústica submarina permitiu utilizar o software de raytracing e calcular as perdas de transmissão ao longo da propagação de cada raio. Sendo pedidos ao utilizador os restantes termos da equação sonar ativo ou passivo, dependendo do contexto em que é aplicada, o software resolve o problema da propagação e apresenta valores de alcance de deteção e de contra deteção, anexos a um gráfico de excesso de sinal em função da distância percorrida pelos raios de som.
Os valores obtidos, assim como o gráfico de excesso de sinal, pretendem ser informação válida e relevante para o planeamento e execução de operações submarinas e antissubmarinas, da perspetiva de navio de superfície como utilizador habitual de sonar ativo e da perspetiva de utilizador habitual de sonar passivo como é o caso do submarino no contexto das operações navais.
From the WOD (World Oceanographic Database) 2013 by NOAA (National Oceanographic and Atmospheric Administration) as well as the GSW (Gibbs-SeaWater) toolbox’s functions, a process that calculates seawater’s conservative temperature and absolute salinity by depth, was developed using MATLAB’s programming language. The resulting profiles are used for calculating the density and sound speed profiles. Subsequently, the developed software solves sound propagation in any position chosen from WOD2013 by the raytracing method. The investigation carried out in the field of submarine acoustics allowed the manipulation of the raytracing software in calculating the transmission loss along each ray propagation. Afterwards, the user must determine, depending on the context, which sonar equation will be used. Whether passive or active, the remaining factors of the sonar equation ought to be introduced by the user to obtain predicted sonar range and counter detection range, as well as a signal excess graph, as function of the distance travelled by each sound ray. The resulting values and the signal excess graph shall be relevant and useful information for planning and carrying out submarine or anti-submarine operations, while aboard a surface ship operating active sonar or as submarine’s passive sonar operator.
From the WOD (World Oceanographic Database) 2013 by NOAA (National Oceanographic and Atmospheric Administration) as well as the GSW (Gibbs-SeaWater) toolbox’s functions, a process that calculates seawater’s conservative temperature and absolute salinity by depth, was developed using MATLAB’s programming language. The resulting profiles are used for calculating the density and sound speed profiles. Subsequently, the developed software solves sound propagation in any position chosen from WOD2013 by the raytracing method. The investigation carried out in the field of submarine acoustics allowed the manipulation of the raytracing software in calculating the transmission loss along each ray propagation. Afterwards, the user must determine, depending on the context, which sonar equation will be used. Whether passive or active, the remaining factors of the sonar equation ought to be introduced by the user to obtain predicted sonar range and counter detection range, as well as a signal excess graph, as function of the distance travelled by each sound ray. The resulting values and the signal excess graph shall be relevant and useful information for planning and carrying out submarine or anti-submarine operations, while aboard a surface ship operating active sonar or as submarine’s passive sonar operator.
Description
Keywords
WOD2013 MATLAB GSW temperatura conservativa velocidade do som raytracing acústica submarina equação sonar deteção.