Patent ID: 9562984
Date: 2017-02-07
CPC Classifications: G01C,G01V

Claim:
1. A method of providing a stable timing signal for a seismic data acquisition unit, comprising: generating, via a local oscillator of the seismic data acquisition unit, a local timing signal; receiving, by a wireless receiver of the seismic data acquisition unit, an external time reference; disciplining, via the wireless receiver, the local oscillator based on the external time reference; determining a frequency error of the local oscillator by differencing time stamps of the external time reference over a frequency measurement time interval, wherein the frequency measurement time interval corresponds to a frequency accuracy for a variable time stamp uncertainty; measuring, via at least one environmental sensor, at least one environmental parameter for the seismic data acquisition unit, the at least environmental parameter including an inclination of the seismic data acquisition unit; storing, in a memory element of the seismic data acquisition unit, a data structure comprising (i) the frequency error, (ii) the time stamps from the external time reference, and (iii) measured environmental parameters encountered over the frequency measurement time interval; and during a time interval in which the wireless receiver is disabled, adjusting a frequency of the local oscillator to correct for at least one timing error using data stored in the data structure.