METHOD AND APPARATUS FOR CORRECTING THE TIMING FUNCTION IN A NODAL SEISMIC DATA ACQUISITION UNIT

摘要

A wireless seismic data acquisition unit with a wireless receiver providing access to a common remote time reference shared by a plurality of wireless seismic data acquisition units in a seismic system The receiver replicates local version of remote time epoch to which a seismic sensor analog-to-digital converter is synchronized The receiver replicates local version of remote common time reference for time-stamping local node events The receiver can enter a low power, nonoperational state over penods of time dunng which the seismic data acquisition unit continues to record seismic data, thus conserving unit battery power The system implements a method to correct the local time clock based on intermittent access to the common remote time reference using a voltage controlled oscillator to account for environmentally induced timing errors The invention further provides for a more stable method of correcting drift in the local time clock