水中超音波のドプラー効果を用いた船舶の対地速度測定について

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This paper describes a theoretical and experimental investigation aimed at measuring ship's speed to the ground by means of the Doppler effect of underwater ultrasonics. Measurable quantity of the Doppler effect of underwater ultrasonics is thought to be influenced by the distribution of flow velocity, temperature, and salinity of the water. Assording to the computational formula of the aftereffect obtained by theoretical consideration. calculated speed to the ground is falled within 1% of the real speed to the ground in a numerical example of the aftereffect. It is suggested that the error in calculation of the speed to the ground may be corrected by measuring the Doppler shift frequency in two direction (θ_1 (O<θ_1<90°) and 180°-θ_1). An experimental apparatus is introduced in order that output signal of frequency Δf may emerge from input signal of frequency f_o+Δf and f_o-Δf. The spectrum of the output signal in the experimental towing tank is analysed by the frequency analyser, and it is shown that it has a steep peak. Error of velocity measuremnt is, as a result, shown to be [numerical formula] and [numerical formula], where Δf_DC, Δf_PS and Δf_T are the digital counted, the spectral peak, and the theoretical frequency, respectively.
社団法人日本船舶海洋工学会の論文