| 摘要 |
<p>PURPOSE:To provide an active sonar device for reducing a detection error of a target azimuth, without recourse to a Doppler shift and changes of a water temperature, etc. CONSTITUTION:A wavelength arithmetic circuit 1 finds a target echo wavelength from the information of a transmitting frequency, target Doppler frequency and underwater sound speed. A beam function reader 2 finds a beam conversion angle corresponding to the value of the target echo wavelength from a beam conversion table 3. A vector arithmetic circuit 4 carries out a vector operation about the complex data for which SB(split beam) correlation treatment is made. An inverse tangent function reader 5 finds an electric phase difference corresponding to a vector operation value from an inverse tangent function table 6. A conversion coefficient arithmetic circuit 7 finds an angle conversion coefficient, by using the each value of the target echo wavelength, beam conversion angle, vector operation value and phase difference. An inverse sine function reader 8 finds an azimuth corresponding to the angle conversion coefficient from an inverse sine function table 9.</p> |
