Compact underwater electromagnetic measurement system using magnetic sensors and electrical sensors having capacitive electrodes
First Claim
1. A system for measuring magnetic and electric fields present in an electrically conducting medium, the system comprising:
- a group of components constituting an integrated sensor package including;
two magnetic sensors, each magnetic sensor having a magnetic field induction coil for producing a magnetic field signal and a magnetic field signal amplifier connected to the induction coil for producing an amplified magnetic field signal based on the magnetic field signal, each induction coil being disposed so as to measure fields in orthogonal directions;
two electric field sensors, each electric field sensor having an electric field signal amplifier connected to at least two electric potential antennas for producing an amplified electric field signal, each electric field sensor being disposed so as to measure fields in orthogonal directions, the at least two electric potential antennas each including a respective capacitive electrode being adapted to measure an electric potential and having a conducting core and an electrically insulative layer covering the core, said insulative layer preventing transfer of a resistive current from the core to the medium;
a data acquisition system for receiving the amplified electric field signals and the amplified magnetic field signals and storing data representative thereof; and
a power supply for providing electrical power to the data acquisition system, the electric sensors and the magnetic sensors.
2 Assignments
0 Petitions
Accused Products
Abstract
An underwater EM measurement system, which is substantially smaller, much simpler to use, and more robust than prior systems, is formed as a sensor package integrated into a single pressure vessel includes two magnetic sensors including induction coils disposed substantially horizontally so as to measure fields in orthogonal directions. The package also includes two electric field sensors including electric potential antennas adapted to couple to a water potential via a capacitive electrode having a conducting material and an electrically insulative layer formed of an insulating material. The capacitive electrode has a capacitance to the medium of greater than 1 mF. Preferably, the insulating material is a metal oxide.
-
Citations
24 Claims
-
1. A system for measuring magnetic and electric fields present in an electrically conducting medium, the system comprising:
a group of components constituting an integrated sensor package including; two magnetic sensors, each magnetic sensor having a magnetic field induction coil for producing a magnetic field signal and a magnetic field signal amplifier connected to the induction coil for producing an amplified magnetic field signal based on the magnetic field signal, each induction coil being disposed so as to measure fields in orthogonal directions; two electric field sensors, each electric field sensor having an electric field signal amplifier connected to at least two electric potential antennas for producing an amplified electric field signal, each electric field sensor being disposed so as to measure fields in orthogonal directions, the at least two electric potential antennas each including a respective capacitive electrode being adapted to measure an electric potential and having a conducting core and an electrically insulative layer covering the core, said insulative layer preventing transfer of a resistive current from the core to the medium; a data acquisition system for receiving the amplified electric field signals and the amplified magnetic field signals and storing data representative thereof; and a power supply for providing electrical power to the data acquisition system, the electric sensors and the magnetic sensors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
15. A method for measuring an electric field present in an electrically conducting medium below a surface of the medium comprising;
-
deploying electrodes on a rigid structure that provides a defined electrode separation; preventing a transfer of a resistive current from the electrodes to the medium; measuring either a differential signal from the electrode or a signal from each electrode; producing an amplified electric field signal by either amplifying the differential signal from the electrodes or amplifying the signal from each electrode first and then taking the difference; and storing the amplified electric field signal. - View Dependent Claims (16)
-
-
17. A method for measuring electric and magnetic fields present below a surface of a body of water comprising;
-
deploying a system including at least two electric field sensors, each field sensor having an electric field signal amplifier connected to at least two electric potential antennas, the at least two electric potential antennas each including a respective capacitive electrode, and magnetic field sensors, having at least two magnetic field induction coils, arranged in a plane under the water; measuring the electric and magnetic fields in orthogonal directions to produce signals representative of the electric and magnetic fields; preventing a transfer of a resistive current from at least one of the electrodes to the water; amplifying the signals from the electric potential antennas and magnetic field induction coils to produce amplified electric field signals and amplified magnetic field signals, respectively; and storing the amplified electric field signals and amplified magnetic field signals. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
-
Specification