Surgical tools having electromagnetic tracking components

1. A method comprising:

providing a surgical tool comprising:

an elongate shaft including a flexible shaft portion and a rigid portion attached to the flexible shaft portion; and

a plurality of electromagnetic (EM) sensors disposed at least partially within the elongate shaft, the plurality of EM sensors including a first EM sensor and a second EM sensor, wherein:

the first EM sensor comprises a first coil and a first core; and

the second EM sensor comprises a second coil and a second core that extends beyond the second coil, the second EM sensor extending along a majority of a length of the rigid portion;

introducing a tip of the surgical tool into a luminal network of a patient;

determining a voltage measurement between the first and second EM sensors of the plurality of EM sensors, and

determining an orientation of the surgical tool based on the determined voltage measurement.

2. The method of claim 1 , wherein the first core does not extend beyond the first coil.

3. The method of claim 1 , wherein a difference in at least one of length or direction of core extension between the first and second EM sensors provides an increased differential voltage between the first and second EM sensors.

4. The method of claim 1 , wherein the first and second EM sensors are spaced a common distance from an end of the elongate shaft.

5. The method of claim 1 , wherein a first one of the first and second EM sensors is placed closer to a tip of the elongate shaft than a second one of the first and second EM sensors.

6. The method of claim 1 , wherein at least one of the plurality of EM sensors is positioned between an illumination source and a working channel of the surgical tool.

7. The method of claim 1 , wherein the second core extends beyond the second coil internally.

8. The method of claim 1 , wherein:

the second core is a ferrite core; and

the ferrite core extends externally from a distal end of the elongate shaft.

9. The method of claim 8 , wherein the ferrite core has a force sensing component associated therewith.

10. The method of claim 9 , wherein an external free end of the ferrite core has a force perception structure associated therewith.

11. A method comprising:

providing a surgical tool comprising:

an elongate shaft including a flexible shaft portion and a rigid portion attached to the flexible shaft portion;

a first electromagnetic (EM) sensor comprising a first coil and a first ferrous core; and

a second EM sensor comprising a second coil and a second ferrous core that extends beyond the second coil, the second EM sensor extending along a majority of a length of the rigid portion;

introducing a tip of the surgical tool into a luminal network of a patient;

determining a voltage measurement between the first and second EM sensors; and

determining an orientation of the surgical tool based on the determined voltage measurement.

12. The method of claim 11 , wherein the second ferrous core extends externally from a distal end of the elongate shaft.

13. The method of claim 12 , wherein the second ferrous core has a force perception structure associated with an end thereof.

14. The method of claim 13 , wherein the force perception structure has a pyramid shape.

15. The method of claim 13 , wherein the force perception structure has a ball shape.

16. The method of claim 13 , wherein the force perception structure is configured to generate a force output in response to physical contact with patient anatomy.

17. The method of claim 11 , wherein the voltage measurement is a differential measurement between the first EM sensor and the second EM sensor.

18. The method of claim 11 , wherein the first ferrous core of the first EM sensor differs from the second ferrous core of the second EM sensor with respect to at least one of length or direction to provide increased differential between voltage measurements between the first and second EM sensors.