PURPOSE: To measure a propagation time accurately by determining the correlation between a transmission signal from a sound source on the water and the receiving signal from a submersible receiver thereby suppressing the effect of noise having low correlation with the transmission signal even if the receiving signal has a low S/N.
CONSTITUTION: The start signal 8 of burst generated from an oscillator 1 is delivered to a transmitter 2 and a correlator 7. The transmitter 2 transmits the burst of the start signal 8 which is received by a receiver 3. The receiving signal is delivered to the correlator 7 where the correlation with the burst of the start signal 8, delivered directly from the oscillator 1 to the correlator 7, is determined. Peaks appear at the time positions of the direct wave and the wave reflected on the surface of the sea on the waveform of correlated values. Since the time between the center of the pulse width of start signal 8 and each peak is determined as each propagation time, the propagation times of direct wave and reflected wave can be determined accurately and the position of the receiver 3 can be measured accurately.
SAIJIYOU KENJI
MATSUNAGA NARIKAZU
SAYAMA SHINICHI
OKI ELECTRIC IND CO LTD
| JPS5780582A | 1982-05-20 | |||
| JPH01118786A | 1989-05-11 | |||
| JPH03277987A | 1991-12-09 | |||
| JPS63249069A | 1988-10-17 |