ELECTROMAGNETIC SYSTEM FOR TIMING SYNCHRONIZATION AND LOCATION DETERMINATION FOR SEISMIC SENSING SYSTEMS HAVING AUTONOMOUS (NODAL) RECORDING UNITS

摘要

A synchronization system for a nodal geophysical data recorder includes an electromagnetic transmitter associated with a master recording unit. The master unit includes devices for determining time and geodetic position from an external reference. The transmitter includes a code generator to cause transmission of a time synchronization signal as a coded sequence. The transmitter is configured to induce an electromagnetic field in at least one of subsurface rock formations and a body of water. At least one nodal geophysical data recorder includes at least one geophysical data sensor. The at least one sensor has measurements there from stored in a data storage device associated with the recorder wherein the recorder includes a clock for time indexing the stored data measurements. The recorder includes a receiver for detecting and decoding the time synchronization signal in the coded sequence to synchronize the clock with the synchronization signal.