Time synchronization for marine controlled source electromagnetic recorder

As an effective method to improve the successful rate of marine oil and gas drilling, marine controlled-source electromagnetic method requires acquisition of many marine controlled-source electromagnetic receivers which record electromagnetic data on the same time axis. However, receiver works on the seabed where GPS signal is shielded and relatively constant temperatures, this will bring about a consequence that the land synchronization method could not be implemented. To get the marine receivers which are time synchronization, we combine the GPS and OCXO (Oven Controlled Crystal Oscillator), and then calculate time drift. This method makes time drift down minimum by time drift compensation between different receivers.