Abstract: In order to obtain raw and accurate data processing section of ocean bottom seismograph (OBS) in marine geophysical exploration, negative effects of positional time and positional accuracy in acquisition and processing must be eliminated. Through analyzing the effects of the accuracy of positional time in OBS data processing and analyzing the timing error sources, we developed a gun controlling chronograph to improve positional precision and to eliminate conventional timing error; the accuracy can reach 0.01 ms, to realize high accuracy of navigation shotpoint time positioning and timing and to ensure the accuracy in OBS data acquisition. The results of stability testing and production testing show the time fixing capacity of chronograph can meet the demands of OBS multi-component acquisition perfectly, as well as in other marine geophysical prospecting areas that need high accuracy timing.

Key words: gun controlling, time fixing, time chronometer, navigation and position, ocean bottom seismograph, geophysical exploration