Generating magnetic fingerprint for mobile device indoor navigation

1. A method, executed in a processor of a server computing device, of generating a magnetic fingerprint map of an indoor area, the method comprising:

generating a magnetic infrastructure profile of at least a portion of the indoor area, wherein generating the magnetic infrastructure profile comprises identifying a set of polygons corresponding to potential magnetic field interference sources, based on a floorplan of the indoor area;

determining, in the processor, a magnetic field profile based on the magnetic infrastructure profile, wherein the magnetic field profile is determined based on a postulated magnetic model, and wherein determining the magnetic field profile comprises:

classifying each of the set of polygons, based on a magnetic potential of a type of magnetic field interference source corresponding to a polygon; and

assigning, based on the type of the magnetic interference source, default initial values to magnetic field profile parameters of each of the set of polygons, the default initial values being based on the postulated magnetic model; and

generating an association of the magnetic field profile parameters associated with respective locations within the indoor area as the magnetic fingerprint map.

2. The method of claim 1 wherein the magnetic infrastructure profile comprises at least one of a wall, a support column, an elevator, a fixedly located electronic equipment, a support beam, a stairwell, an escalator, a ceiling, and an electro-mechanical power plant.

3. The method of claim 1 wherein the magnetic infrastructure profile comprises at least one of a steel structural element and a ferro-magnetic structural element.

4. The method of claim 1 wherein the postulated mathematical magnetic model includes at least a lengthy ferromagnetic element (LFME).

5. The method of claim 1 wherein the magnetic field profile parameters comprise at least one of a magnetic field strength and a magnetic dip angle.

6. The method of claim 1 wherein the magnetic field parameters comprise at least one of an x, y, z magnetic field vector component.

7. The method of claim 5 wherein the magnetic field parameters comprise a magnetic direction.

8. The method of claim 1 wherein the indoor area comprises at least one of a manufacturing facility, a shopping mall, a warehouse, an airport facility, a hospital facility, a university campus facility or an at least partially enclosed building.

9. A server computing system for magnetic fingerprinting of an indoor area, the server computing system comprising:

a processor; and

a memory including instructions executable in the processor to:

generate a magnetic infrastructure profile of at least a portion of the indoor area wherein generating the magnetic infrastructure profile comprises identifying a set of polygons corresponding to potential magnetic field interference sources, based on a floorplan of the indoor area;

determine, in the processor, a magnetic field profile based on the magnetic infrastructure profile, wherein the magnetic field profile is determined based on a postulated magnetic model, and wherein determining the magnetic field profile comprises:

classifying each of the set of polygons, based on a magnetic potential of a type of magnetic field interference source corresponding to a polygon; and

assigning, based on the type of the magnetic interference source, default initial values to magnetic field profile parameters of each of the set of polygons, the default initial values being based on the postulated magnetic model; and

generate an association of the magnetic field profile parameters associated with respective locations within the indoor area as the magnetic fingerprint map.

10. The system of claim 9 wherein the magnetic infrastructure profile comprises at least one of a wall, a support column, an elevator, a fixedly located electronic equipment, a support beam, a stairwell, an escalator, a ceiling, and an electro-mechanical power plant.

11. The system of claim 9 wherein the magnetic infrastructure profile comprises at least one of a steel structural element and a ferro-magnetic structural element.

12. The system of claim 9 wherein the postulated mathematical magnetic model includes at least a lengthy ferromagnetic element (LFME).

13. The system of claim 9 wherein the magnetic field profile parameters comprise at least one of a magnetic field strength and a magnetic dip angle.

14. The system of claim 9 wherein the magnetic field parameters comprise at least one of an x, y, z magnetic field vector component.

15. The system of claim 9 wherein the magnetic field parameters comprise a magnetic direction.

16. The system of claim 9 wherein the indoor area comprises at least one of a manufacturing facility, a shopping mall, a warehouse, an airport facility, a hospital facility, a university campus facility or an at least partially enclosed building.

17. The method of claim 1 , wherein determining the magnetic field profile further comprises refining the default initial values of the magnetic field profile parameters to generate the magnetic field profile.

18. The method of claim 1 , wherein determining the magnetic field profile further comprises

georeferencing the floor plan, to determine geolocation of endpoints of each line representing an LFME;

estimating an angle that the LFME makes with the geomagnetic field, based on the georeferencing;

estimating a length of the LFME, based on the georeferencing; and

determining the magnetic field parameters for the geolocation, based on the estimated angle and the estimated length of the LFME.

19. The system of claim 9 , wherein determining the magnetic field profile further comprises refining the default initial values of the magnetic field profile parameters to generate the magnetic field profile.

20. The system of claim 9 , wherein determining the magnetic field profile further comprises

georeferencing the floor plan, to determine geolocation of endpoints of each line representing an LFME;

estimating an angle that the LFME makes with the geomagnetic field, based on the georeferencing;

estimating a length of the LFME, based on the georeferencing; and

determining the magnetic field parameters for the geolocation, based on the estimated angle and the estimated length of the LFME.