Patent ID: 8649992
Filing Date: 2014-02-11
Classification: G01V,Y02A

Abstract:
1. A method for reducing effect of motion on electromagnetic signals detected while moving an electromagnetic receiver through a body of water, comprising: towing a transmitter cable comprising an electromagnetic transmitter through the body of water; towing a separate receiver cable comprising the electromagnetic receiver through the body of water measuring a parameter related to an amount of current passed through the electromagnetic transmitter, wherein the measuring is done as close to the electromagnetic transmitter as possible; measuring a magnetic field proximate the electromagnetic receiver, wherein the measuring a magnetic field proximate the receiver comprises measuring voltage induced in three mutually orthogonal wire coils; estimating a transmitter portion of the measured magnetic field from the measured parameter related to the amount of current; estimating a motion portion of the measured magnetic field from the estimated transmitter portion of the measured magnetic field; estimating a voltage induced in the receiver from the estimated motion portion of the measured magnetic field; and correcting voltage signals detected by the receiver using the estimated voltage.