Electromagnetic receiver tracking and real-time calibration system and method
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 tracking EM transmitter for generating tracking signals within a second frequency range; and a receiver section including a receiver that measures both the survey EM signals and the tracking signals.
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 tracking reference frame;
plural tracking EM transmitters for generating tracking signals within a second frequency range, wherein the plural tracking EM transmitters are rigidly attached to the tracking reference frame; and
a receiver section, including a receiver housing and a receiver, that measures both the survey EM signals and the tracking signals,
wherein the receiver housing is attached with a connecting mechanism to the tracking reference frame so that the receiver housing freely translates and rotates in all directions.
2. The system of claim 1 , wherein the receiver includes three mutually orthogonal coils, each independently measuring each of the tracking signals.
3. The system of claim 1 , further comprising:
a controller connected to the receiver and configured to calculate a position and orientation of the receiver relative to the tracking reference frame, based on the recorded tracking signals.
4. The system of claim 1 , further comprising:
a synchronization unit for controlling and processing signals in the EM system.
5. The system of claim 1 , wherein each tracking EM transmitter includes two or three mutually orthogonal transmitter coils.
6. The system of claim 1 , wherein the receiver includes two or three mutually orthogonal receiver coils.
7. The system of claim 1 , further comprising:
an additional receiver having two or three mutually orthogonal receiver coils.
8. The system of claim 7 , wherein the additional receiver is used exclusively for tracking purposes.
9. The system of claim 1 , wherein the EM transmitter includes two or three mutually orthogonal transmitter coils and each transmitter coil independently generates the EM signals.
10. The system of claim 1 , further comprising:
an inertial system that has accelerometers and roll rate sensors for measuring position and orientation.
11. The system of claim 1 , wherein a distance between the receiver and a tracking EM transmitter of the plural tracking EM transmitters is smaller than a radius of the survey transmitter.
12. An electromagnetic (EM) system for measuring EM signals, the EM system comprising:
a transmitter section;
a receiver section;
a tracking reference frame; 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
plural tracking EM transmitters for generating tracking signals within a second frequency range, wherein the plural tracking EM transmitters are rigidly attached to the tracking reference frame,
wherein the receiver section includes a receiver housing and a receiver that measures both the survey EM signals and the tracking signals, and
wherein the receiver housing is attached with a connecting mechanism to the tracking reference frame so that the receiver housing freely translates and rotates in all directions.
13. The system of claim 12 , wherein the receiver includes three mutually orthogonal coils, each independently measuring each of the tracking signals.
14. The system of claim 12 , further comprising:
a controller connected to the receiver and configured to calculate a position and orientation of the receiver relative to the tracking reference frame based on the recorded tracking signals.
15. The system of claim 12 , wherein each tracking EM transmitter includes two or three mutually orthogonal transmitter coils.
16. The system of claim 12 , wherein the receiver includes two or three mutually orthogonal receiver coils.
17. The system of claim 12 , further comprising:
an additional receiver having two or three mutually orthogonal receiver coils.
18. A method for determining the position and/or orientation of an electromagnetic (EM) receiver, the method comprising:
crossing a given exploration area with a transmitter section, wherein the transmitter section includes a survey EM transmitter for generating survey EM signals within a first frequency range and plural tracking EM transmitters for generating tracking signals within a second frequency range, wherein the plural tracking EM transmitters are rigidly attached to a tracking reference frame; and
recording with a receiver section, including a receiver housing and a receiver, both the survey EM signals and the tracking signals,
wherein the receiver housing is attached with a connecting mechanism to the tracking reference frame so that the receiver housing freely translates and rotates in all directions.
19. The method of claim 18 , further comprising:
calculating in a controller a position and/or orientation of the receiver relative to the tracking reference frame based on the recorded tracking signals.
20. The method of claim 18 , further comprising:
calibrating a receiver movement compensation from the survey EM signals.