METHOD AND SYSTEM FOR NAVIGATION USING MAGNETIC DIPOLES
A method of navigation includes receiving a magnetic field signal from a magnetic field transducer, the magnetic field signal proportional to sensed magnetic fields associated with magnetic field sources, in a processor, processing the magnetic field signal to determine magnetic field axes of rotation corresponding to rotations of the sensed magnetic fields, and using the magnetic field axes of rotation to render a position of the magnetic field transducer.
1 . A method of navigation, comprising:
receiving a magnetic field signal from a magnetic field transducer, the magnetic field signal proportional to sensed magnetic fields associated with a plurality of magnetic field sources;
in a processor, processing the magnetic field signal to determine a plurality of magnetic field axes of rotation corresponding to rotations of the sensed magnetic fields; and
using the plurality of magnetic field axes of rotation to render a position of the magnetic field transducer.
2 . The method of claim 1 , wherein said using the plurality of magnetic field axes of rotation to render the position of the magnetic field transducer comprises:
determining a plurality of orientations of the magnetic field axes of rotation relative to a predetermined coordinate system; and
using the plurality of orientations of the magnetic field axes of rotation to render the position of the magnetic field transducer.
3 . The method of claim 2 , wherein the position of the magnetic field transducer is a fixed position.
4 . The method of claim 1 , wherein said using the plurality of magnetic field axes of rotation to render the position of the magnetic field transducer comprises:
determining a predetermined number of angles between the magnetic field axes of rotation; and
rendering the position of the magnetic field transducer using the predetermined number of angles.
5 . The method of claim 4 , wherein the predetermined number of angles is at least three angles and the rendered position includes at least one of position information or orientation information.
6 . The method of claim 4 , wherein the predetermined number of angles is six angles and the rendered position includes a three-dimensional position and a three-dimensional orientation.
7 . The method of claim 4 , wherein the magnetic field transducer is a rotating magnetic field transducer.
8 . The method of claim 4 , further comprising:
rendering a position of at least one of the magnetic field sources using the predetermined number of angles.
9 . The method of claim 1 , wherein the position of the magnetic field transducer corresponds to a position of an object of interest coupled to the magnetic field transducer.
10 . The method of claim 1 , wherein the magnetic field transducer comprises a magnetometer.
11 . The method of claim 1 , wherein the plurality of magnetic field sources comprises:
a first spinning dipole generated at a first transmitter having a first predetermined position;
a second spinning dipole generated at a second transmitter having a second predetermined position; and
a third spinning dipole generated at a third transmitter having a third predetermined position,
wherein the first, second, and third predetermined positions form a triangle.
12 . The method of claim 11 , wherein the triangle is formed about a navigation area of interest including the magnetic field transducer.
13 . The method of claim 1 , wherein the plurality of magnetic field sources rotate about a plurality of magnetic field source axes of rotation and are positioned to form a navigation area of interest, further comprising:
rotating each magnetic field source axis of rotation about a respective axis perpendicular to a plane formed by the plurality of magnetic field sources to align each magnetic field source axis of rotation with a successive one of the magnetic field sources.
14 . The method of claim 13 , further comprising:
rotating at least one of the magnetic field source axes of rotation about a respective axis coincident with the plane formed by the plurality of magnetic field sources to avoid a condition in which the magnetic field transducer is coincident with a plane formed by the magnetic field associated with the at least one magnetic field source axis of rotation.
15 . A navigation system, comprising:
a processor to receive a magnetic field signal from a magnetic field transducer, the magnetic field signal proportional to sensed magnetic fields associated with a plurality of magnetic field sources;
a memory coupled to the processor, the memory including program instructions for providing navigation information by:
processing the magnetic field signal to determine a plurality of magnetic field axes of rotation corresponding to rotations of the sensed magnetic fields; and
using the plurality of magnetic field axes of rotation to render a position of the magnetic field transducer.
16 . The system of claim 15 , said using the plurality of magnetic field axes of rotation to render a position of the magnetic field transducer comprises:
determining a plurality of orientations of the magnetic field axes of rotation relative to a predetermined coordinate system; and
using the plurality of orientations of the magnetic field axes of rotation to render the position of the magnetic field transducer.
17 . The system of claim 16 , wherein the position of the magnetic field transducer is a fixed position.
18 . The system of claim 15 , said using the plurality of magnetic field axes of rotation to render a position of the magnetic field transducer comprises:
determining a predetermined number of angles between the magnetic field axes of rotation; and
rendering a position of the magnetic field transducer using the predetermined number of angles.
19 . The system of claim 18 , wherein the predetermined number of angles is at least three angles and the rendered position includes at least one of position information or orientation information.
20 . The system of claim 18 , wherein the predetermined number of angles is six angles and the rendered position includes a three-dimensional position and a three-dimensional orientation.
21 . The system of claim 18 , wherein the magnetic field transducer is a rotating magnetic field transducer.
22 . The system of claim 18 , further comprising:
rendering a position of at least one of the magnetic field sources using the predetermined number of angles.
23 . The system of claim 15 , wherein the position of the magnetic field transducer corresponds to a position of an object of interest coupled to the magnetic field transducer.
24 . The system of claim 15 , wherein the magnetic field transducer comprises a magnetometer.
25 . The system of claim 15 , wherein the plurality of magnetic field sources comprises:
a first spinning dipole generated at a first transmitter having a first predetermined position;
a second spinning dipole generated at a second transmitter having a second predetermined position; and
a third spinning dipole generated at a third transmitter having a third predetermined position,
wherein the first, second, and third predetermined positions form a triangle.
26 . The system of claim 25 , wherein the triangle is formed about a navigation area of interest including the magnetic field transducer.
27 . The system of claim 15 , wherein the plurality of magnetic field sources rotate about a plurality of magnetic field source axes of rotation and are positioned to form a navigation area of interest, further comprising:
rotating each magnetic field source axis of rotation about a respective axis perpendicular to a plane formed by the plurality of magnetic field sources to align each magnetic field source axis of rotation with a successive one of the magnetic field sources.
28 . The system of claim 27 , further comprising:
rotating at least one magnetic field source axis of rotation about a respective axis coincident with the plane formed by the plurality of magnetic field sources to avoid a condition in which the magnetic field transducer is coincident with a plane formed by the magnetic field associated with the at least one magnetic field source axis of rotation.
29 . A computer-readable medium having encoded thereon software for providing navigation information, said software comprising instructions for:
determining a plurality of magnetic field axes of rotation corresponding to rotations of magnetic fields sensed by a magnetic field transducer and associated with a plurality of magnetic field sources; and
processing the plurality of magnetic field axes of rotation to render a position of the magnetic field transducer.
30 . The computer-readable medium of claim 1 , wherein said processing the plurality of magnetic field axes of rotation to render a position of the magnetic field transducer comprises:
determining a plurality of orientations of the magnetic field axes of rotation relative to a predetermined coordinate system; and
using the plurality of orientations of the magnetic field axes of rotation to render the position of the magnetic field transducer.
31 . The computer-readable medium of claim 29 , wherein said processing the plurality of magnetic field axes of rotation to render a position of the magnetic field transducer comprises:
determining a predetermined number of angles between the magnetic field axes of rotation; and
rendering the position of the magnetic field transducer using the predetermined number of angles.
32 . The computer-readable medium of claim 31 , wherein the predetermined number of angles is at least three angles and the rendered position includes at least one of position information or orientation information.
33 . The computer-readable medium of claim 31 , wherein the predetermined number of angles is six angles and the rendered position includes a three-dimensional position and a three-dimensional orientation.
34 . The computer-readable medium of claim 31 , wherein the magnetic field transducer is a rotating magnetic field transducer.
35 . The computer-readable medium of claim 31 , said software further comprising instructions for:
rendering a position of at least one of the magnetic field sources using the predetermined number of angles.
36 . The computer-readable medium of claim 29 , wherein the position of the magnetic field transducer corresponds to a position of an object of interest coupled to the magnetic field transducer.
37 . The computer-readable medium of claim 29 , wherein the magnetic field transducer comprises a magnetometer.