SIMULTANEOUS LOCALIZATION AND MAPPING BY USING EARTH'S MAGNETIC FIELDS

• US 20160116290A1
• Filed: 10/27/2014
• Published: 04/28/2016
• Est. Priority Date: 10/27/2014
• Status: Active Grant

• Current Assignee: IndoorAtlas Oy
• Original Assignee: IndoorAtlas Oy
• Inventors: HAVERINEN, Janne, RAHTU, Esa
• Granted Patent: US 9,476,717 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01C 21/08 involving use of the magnetic field of the earth
• CPC Class Codes: G01C 21/14 by recording the course traversed by the object G01C21/16 takes precedence
• CPC Class Codes: G01C 21/1654 with electromagnetic compass
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01R 33/10 Plotting field distribution ; Measuring field distribution
• CPC Class Codes: G01S 2205/02 Indoor
• CPC Class Codes: G01S 5/02522 The radio-map containing measured values of non-radio values
• CPC Class Codes: G01S 5/0264 at least one of the systems being a non-radio wave positioning system
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves
• CPC Class Codes: G01V 3/40 specially adapted for measuring magnetic field characteristics of the earth
• CPC Class Codes: G01V 7/00 Measuring gravitational fields or waves; Gravimetric prospecting or detecting
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

There is provided an apparatus configured to perform operations comprising: acquiring motion data sets from the plurality of mobile devices; estimating route models of the travelled routes on the basis of the motion data sets; generating EMF fingerprints for the travelled routes by associating the acquired EMF data sets with corresponding points of the route models; and determining the locations of the routes with respect to each other on the basis of at least one of the following: the EMF fingerprints and the route models.

Claims

1. An apparatus, comprising:

at least one processor and at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to perform operations comprising;

acquiring indoor non-labeled Earth'"'"'s magnetic field, EMF, data sets representing at least one of magnitude and direction of the EMF in a building from a plurality of mobile devices, wherein routes corresponding to the non-labeled EMF data sets in the building are unknown;

acquiring motion data sets from the plurality of mobile devices;

estimating route models of the travelled routes on the basis of the motion data sets;

generating EMF fingerprints for the travelled routes by associating the acquired EMF data sets with the route models; and

determining the locations of the routes with respect to each other on the basis of at least one of the following;

the EMF fingerprints and the route models.

2. The apparatus of claim 1, wherein apparatus is further caused to perform operations comprising:

acquiring location dependent data of the mobile devices; and

limiting a geographical location of a given mobile device on the basis of the location dependent data related to that mobile device, thereby clustering the data sets from the plurality of mobile devices geographically; and

applying the clustering when determining the locations of the routes with respect to each other.

3. The apparatus of claim 2, wherein the location dependent data comprises data related to at least one of the following:

measured WiFi radio frequency signal, identifier of an WiFi or Bluetooth access point, measured satellite radio frequency signal, measured air pressure, measured Bluetooth radio frequency signal, measured cellular radio frequency signal, identifier of the mobile device, measured direction of the Earth magnetic field, audio signal, video signal, image(s), ambient light, humidity, location-dependent event.

4. The apparatus of claim 1, wherein the apparatus is further caused to perform operations comprising:

clustering the plurality of the mobile devices geographically on the basis of the generated EMF fingerprints.

5. The apparatus of claim 1, wherein the apparatus is further caused to:

generating an EMF map of the building on the basis of the locations of the routes with respect to each other and the EMF fingerprints.

6. The apparatus of claim 1, wherein the apparatus is further caused to:

generating a floor plan of the building on the basis of the locations of the routes with respect to each other.

7. The apparatus of claim 1, wherein the apparatus is further caused to:

detecting that a single EMF fingerprint corresponding to one mobile device comprises a similar EMF sequence at two parts of the route model; and

determining, based on the detection, that a route loop closure occurs along that part of the route model.

8. The apparatus of claim 7, wherein the apparatus is further caused to:

detecting that the route model, estimated on the basis of the motion data set acquired from that mobile device, does not coincide at the part of the route loop closure;

determining that the inertial sensors of that mobile device have drifted and thereby cause the route model not to coincide; and

causing a correction of the motion data set related to that mobile device, thereby reshaping the route model of that mobile device.

9. The apparatus of claim 1, wherein the apparatus is further caused to:

detecting that at least part of a first EMF fingerprint matches, according to a predetermined likelihood, with at least part of a second EMF fingerprint;

determining, based on the detection, that the two routes coincide at least partly; and

determining that the points of the route models before and after the matching part of the first and the second EMF fingerprints comprise intersections in the building.

10. The apparatus of claim 1, wherein the apparatus is further caused to:

acquiring indications of items of interest from the mobile devices;

associating each item of interest to a corresponding point of a corresponding route model; and

determining the locations of the routes with respect to each other further on the basis of the indicated items of interests.

11. The apparatus of claim 1, wherein the apparatus stores a floor plan of the building, and the apparatus is further caused to:

placing the routes in the floor plan on the basis of the route models and the stored floor plan of the building.

12. The apparatus of claim 11, wherein the apparatus is further caused to:

detecting that the route model, estimated on the basis of the motion data set acquired from that mobile device, does not fit correctly to any route on the floor plan;

estimating the most probably travelled route of the floor plan on the basis of the motion data set acquired from that mobile device and consider that route as the travelled route;

determining that the inertial sensors of that mobile device have drifted and thereby cause the route model not to match with the most probably travelled route; and

causing a correction of the motion data set related to that mobile device, thereby reshaping the route model of that mobile device.

13. The apparatus of claim 11, wherein the apparatus is further caused to:

detecting that the route model, estimated on the basis of the motion data set acquired from that mobile device, does not fit correctly to any route on the floor plan;

determining that the stored floor plan is not up-to-date; and

updating the floor plan on the basis of the route model.

14. The apparatus of claim 1, wherein the apparatus is further caused to:

determining a correction measure for at least one mobile device, wherein the correction measure of the mobile device indicates how to adjust the data sets related to that mobile device; and

causing an adjustment of the data sets related to the mobile device on the basis of the corresponding correction measure.

15. The apparatus of claim 14, wherein the correction measure for a given mobile device is based on at least one of the following:

known bias of the mobile device, software applications being run in the mobile device, type and/or model of the mobile device.

16. The apparatus of claim 1, wherein the apparatus is further caused to:

determining a reliability measure for each mobile device, wherein the reliability measure of a mobile device indicates whether the data sets received from that mobile device are reliable or not; and

weighting the received data sets from the mobile devices on the basis of the corresponding reliability measures.

17. The apparatus of claim 1, wherein the apparatus initially stores at least part of the EMF map of the building, and the apparatus is further caused to:

updating the EMF map and/or enlarging the coverage area of the EMF map on the basis of the acquired EMF data sets and the route models.

18. The apparatus of claim 1, wherein the apparatus is further caused to:

acquiring radio frequency based measurement results from the mobile device;

associating the radio frequency based measurement results with corresponding points of the route models; and

generating and/or updating a radio frequency map of the building on the basis of the acquired radio frequency based measurement results and the associations.

19. A method, comprising:

acquiring, by an apparatus, indoor non-labeled Earth'"'"'s magnetic field, EMF, data sets representing at least one of magnitude and direction of the EMF in a building from a plurality of mobile devices, wherein routes corresponding to the non-labeled EMF data sets in the building are unknown;

acquiring motion data sets from the plurality of mobile devices;

estimating route models of the travelled routes on the basis of the motion data sets;

generating EMF fingerprints for the travelled routes by associating the acquired EMF data sets with corresponding points of the route models; and

determining the locations of the routes with respect to each other on the basis of at least one of the following;

the EMF fingerprints and the route models.

20. A computer program product embodied on a distribution medium readable by a computer and comprising program instructions which, when loaded into an apparatus, execute a method comprising:

acquiring motion data sets from the plurality of mobile devices;

estimating route models of the travelled routes on the basis of the motion data sets;

generating EMF fingerprints for the travelled routes by associating the acquired EMF data sets with corresponding points of the route models; and

determining the locations of the routes with respect to each other on the basis of at least one of the following;

the EMF fingerprints and the route models.