| 摘要 |
PURPOSE:To improve the recognition differential to achieve easily the target detection, by sampling phase information of a target in a time section, which can be set preliminarily, to obtain a sectional error variance and displaying the output only when the echo of the target is inputted. CONSTITUTION:Phases of outputs of plural electroacoustic transducers are arranged, and two, left and right receiving beams having the same receiving directivity with respect to an optional direction are formed in a split beam forming circuit 2, and the correlation between these beam outputs is operated by a correlation operating circuit 3, and the phase difference of the sonar target is obtained on a basis of the output of the circuit 3 by a phase difference detecting circuit 4, and the direction and the amplitude of the sonar target are outputted from an output detecting circuit 5. The error variance on the time base of the phase difference obtained by the circuit 4 is sampled successively in time sections, which can be specified optionally preliminarily in accordance with conditons of sonar operation or the like, by a sectional error variance circuit 6, and sectional error variances are compared with a threshold, which can be specified preliminarily in accordance with conditions of sonar operation or the like, in a threshold setting circuit 7, and the output of the circuit 5 is displayed only when a sonar target signal where the sectional error variance is lower than the threshold is inputted, and thus, the target is detected easily. |
