Electromagnetic receiver tracking and real-time calibration system and method

Patent metadata

Field	Value
Publication number	US-10948620-B2
Application number	US-201916419322-A
Country	US
Kind code	B2
Filing date	May 22, 2019
Priority date	Apr 7, 2014
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

An electromagnetic (EM) receiver system for measuring EM signals. The EM receiver system includes a survey EM transmitter for generating survey EM signals within a first frequency range; a calibration EM transmitter for generating a calibration signal; a receiver section, including a receiver housing and a receiver, that measures both the survey EM signals and the calibration signal; and a calibration device connected to the calibration EM transmitter and to the receiver, the calibration device configured to control a frequency and waveform of the calibration signal. The calibration device is further configured to calculate a response function of the receiver, based on the calibration signal.

First claim

What is claimed is:

1. An electromagnetic (EM) system for measuring EM signals, the EM system comprising:
a survey EM transmitter for generating survey EM signals within a first frequency range;
a calibration EM transmitter for generating a calibration signal;
a receiver section, including a receiver housing and a receiver, that measures both the survey EM signals and the calibration signal; and
a calibration device connected to the calibration EM transmitter and to the receiver, the calibration device configured to control a frequency and waveform of the calibration signal,
wherein the calibration device is further configured to calculate a response function of the receiver, based on the calibration signal.

2. The system of claim 1 , wherein the calibration device includes a controller and the controller is configured to subtract the response function of the receiver from the measured survey EM signals.

3. The system of claim 1 , wherein the calibration device is located on a reference frame to which the receiver housing is connected to with a connecting mechanism.

4. The system of claim 1 , wherein the calibration device is located on the receiver housing.

5. The system of claim 1 , further comprising:
a tracking EM transmitter for generating tracking signals within a second frequency range,
wherein the receiver section is configured to measure the tracking signals.

6. The system of claim 5 , wherein the calibration device is integrated inside the tracking EM transmitter.

7. The system of claim 5 , wherein the receiver includes three mutually orthogonal coils, each independently measuring each of the tracking signals.

8. The system of claim 1 , wherein the calibration signal is emitted during an ON-time of the survey EM signals.

9. The system of claim 1 , wherein the calibration signal has a different frequency for each ON-time cycle of the survey EM signals.

10. The system of claim 1 , wherein the calibration signal has a frequency that is a harmonic of a frequency of the survey EM signals.

11. An electromagnetic (EM) system for measuring EM signals, the EM system comprising:
a transmitter section;
a receiver section;
a calibration device configured to control a frequency and waveform of a calibration signal; and
a tow assembly connecting the transmitter section and the receiver section to an aircraft,
wherein the transmitter section includes a survey EM transmitter for generating survey EM signals within a first frequency range, and a calibration EM transmitter for generating the calibration signal,
wherein the receiver section includes a receiver housing and a receiver that measures both the survey EM signals and the calibration signal, and
wherein the calibration device is further configured to calculate a response function of the receiver, based on the calibration signal.

12. The system of claim 11 , wherein the calibration device includes a controller and the controller is configured to subtract the response function of the receiver from the measured survey EM signals.

13. The system of claim 11 , wherein the calibration device is located on a reference frame to which the receiver housing is connected to with a connecting mechanism.

14. The system of claim 11 , wherein the calibration device is located on the receiver housing.

15. The system of claim 11 , further comprising:
a tracking EM transmitter for generating tracking signals within a second frequency range,
wherein the receiver section is configured to measure the tracking signals.

16. The system of claim 15 , wherein the calibration device is integrated inside the tracking EM transmitter.

17. The system of claim 11 , wherein the calibration signal is emitted during an ON-time of the survey EM signals.

18. The system of claim 11 , wherein the calibration signal has a different frequency for each ON-time cycle of the survey EM signals and the calibration signal has a frequency that is a harmonic of a frequency of the survey EM signals.

19. A method for calibrating an electromagnetic (EM) receiver, the method comprising:
generating a calibration signal with a calibration device;
applying the calibration signal to a receiver;
measuring a voltage across the receiver to determine a response function of the receiver;
generating survey EM signals with a survey EM transmitter;
measuring with the receiver the survey EM signals; and
calibrating the receiver based on the response function.

20. The method of claim 19 , further comprising:
subtracting the response function from the measured EM signals.

Assignees

• Cgg Services Sas

Inventors

• Miles Philip
• Berringer Jason

Classifications

• G01V3/165 Primary

  operating with magnetic or electric fields produced or modified by the object or by the detecting device (with electromagnetic waves G01V3/17) · CPC title

• G01V3/088

  operating with electric fields (G01V3/082 takes precedence) · CPC title

• G01V3/30

  operating with electromagnetic waves · CPC title

• G01V3/265

  Operating with fields produced by spontaneous potentials, e.g. electrochemicals or produced by telluric currents · CPC title

• G01V3/083

  Controlled source electromagnetic [CSEM] surveying · CPC title