Electromagnetic tracking system and method using a three-coil wireless transmitter

1. An electromagnetic tracking system, said system comprising:

an instrument manipulated by a user to perform a task;

a wireless transmitter for broadcasting a wireless signal, said wireless transmitter located on said instrument;

a receiver assembly for receiving said wireless signal; and

electronics for determining positioning information for said instrument based on a relationship between said receiver assembly and said wireless transmitter.

2. The system of claim 1 , wherein said positioning information comprises at least one of position and orientation of said instrument.

3. The system of claim 1 , wherein said wireless transmitter comprises a wireless transmitter coil trio.

4. The system of claim 1 , wherein said receiver assembly comprises two receiver coil trios.

5. The system of claim 1 , wherein said relationship comprises triangulation between said wireless transmitter and said receiver assembly.

6. The system of claim 1 , wherein said task involves manipulating said instrument outside of said user's line of sight.

7. The system of claim 1 , wherein said instrument comprises a medical instrument.

8. The system of claim 1 , further comprising a wired transmitter located away from said instrument.

9. The system of claim 7 , wherein said wired transmitter is located on an instrument guide for said instrument.

10. The system of claim 1 , wherein said receiver assembly is located on an instrument guide for said instrument.

11. The system of claim 1 , wherein said positioning information is determined by a range and a gain ratio between said wireless transmitter and said receiver assembly.

12. The system of claim 1 , wherein said positioning information is determining using mutual inductance between said wireless transmitter and said receiver assembly.

13. A method for tracking a position of an instrument, said method comprising:

transmitting a signal from a wireless transmitter located on an instrument;

receiving said signal at a receiver assembly; and

determining positioning information for said wireless transmitter based on said signal and a relationship between said wireless transmitter and said receiver assembly.

14. The method of claim 13 , further comprising transmitting a signal from a second transmitter to determine said position information.

15. The method of claim 13 , wherein said determining step further comprises determining positioning information for said wireless transmitter by triangulating between said wireless transmitter and said receiver assembly.

16. The method of claim 13 , wherein said determining step further comprises determining positioning information for said wireless transmitter by determining a range and a gain ratio between said wireless transmitter and said receiver assembly.

17. The method of claim 13 , further comprising determining a magnitude and phase of said signal.

18. The method of claim 13 , further comprising calculating a sum of products of said signal.

19. The method of claim 13 , further comprising determining a mutual inductance between said wireless transmitter and said receiver assembly.

20. The method of claim 13 , further comprising refining said positioning information using a solution fitter.

21. The method of claim 13 , further comprising displaying said positioning information with respect to a reference system.

22. An improved wireless electromagnetic tracking system, said system comprising:

a wireless transmitter coil trio attached to an object, said wireless coil trio transmitting a signal;

a receiver assembly with at least two receiver coil trios; and

a tracker electronics for determining positioning information for said wireless coil based on said wireless coil and said at least two receiver coil trios.

23. The system of claim 22 , wherein said positioning information is determined based on said signal and a triangulation of signals between said wireless coil trio and said at least two receiver coil trios.

24. The system of claim 22 , wherein said positioning information is determined based on a mutual inductance between said wireless coil trio and said at least two receiver coil trios.

25. The system of claim 22 , wherein said position information is determined based on said signal and a gain ratio for said receiver assembly.

26. The system of claim 22 , further comprising a display for displaying said positioning information.