| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To identify the correct position of a target even in a case where a reflection sound from the target is Doppler-shifted. <P>SOLUTION: A sonar system comprises a transmitter 20 and receiver 30 which transceives a fan-shaped fan beam transmitting-sound toward a target, a receiving direction setting part 34 which sets the reflection sound receiving-direction of the receiver 30, and reception signal processing means 37 which identifies the target based on the reflection sound. The transmitter 20 and the receiver 30 are disposed by shifting 90°from each other. A generation circuit part 22 is disposed to generate an excitation signal for each transmitting element. The excitation signal constitutes bulk waves having a constant cycle. The bulk waves are composed of frequency-hopping signals d having at least two-unit excitation signals in line having a different frequency. The reception signal processing means includes: a sample hold circuit 39 which identifies a reflection reception signal from the target for each direction; a replica correlation part 40 for correlating a plurality of unit-excitation signals constituting the sample-held reflection reception signal with a plurality of Doppler-shifted replica signals. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
