| 摘要 |
PURPOSE:To search a target extending over a wide ragne by applying a blanking to an acoustic pulse having with width and thereafter, receiving a reflected echo imedicately against an acoustic pulse having narrow width. CONSTITUTION:An underwater navigating body transmits an acoustic pulse having wide and narrow width to a long distance and a short distance target respectively by a transmitting interval determining circuit 14 and a transmitting pulse width determining circuit 15 which respond to a long distance/short distance commanding circuit 13. At the same time, a switching circuit 20 is switched, a blanking is applied to the long distance target by a gate circuit 23 controlled through a blanking circuit 24, and thereafter, a reflected echo pulse which is not influenced by self-noise is received. On the other hand, an echo pulse by a short distance transmitting pulse which has narrow width and scarcely has self noise is received immediately, and is identified from an echo by the sea bottom, etc. by a reflected echo identification circuit 21. According to this constitution, the underwater navigating body can serch a target extending over a wide range. |
