| 摘要 |
PURPOSE:To utilize effectively a reverberation suppressing force notched filter, by deciding the forecasting reverberation frequency corresponding to a deviation angle of an underwater navigating body based on a steering angle and speed information, and controlling local oscillation frequency, etc. CONSTITUTION:In accordance with a steering angle and a speed of an underwater navigating body such as a torpedo for executing active homing, etc., a deflextion angle calculator 20 calculates a deflextion angle of the navigating body. In accordance with this deflextion angle, forecasting reverberation frequency is generated from a reverberation frequency forecasting device 21, a local oscillator 24 for suppressing the reverberation of an ultrasonic receiving wave is controlled through a controller 22, and local oscillation frequency which is mixed with the ultrasonic receiving signal by a mixing circuit 25 is controlled. In this way, a signal applied to a notched filter 27 is not shifted from center frequency, the filter 27 is utilized effectively, a signal-to-reverberation ratio is elevated, and good homing is executed. In this regard, by controlling the center frequency of the notched filter in accordance with the forecasting reverberation frequency, the same result is obtained. |
