Indoor magnetic field based location discovery

摘要

There is provided an apparatus, wherein the apparatus is caused to acquire a location estimate of a positioning device that is to determine its location inside a building, wherein the location estimate is acquired on the basis of an indoor non-magnetic field based location discovery system; access an indoor Earth's magnetic field, EMF, map of plurality of buildings, wherein the indoor EMF map represents at least one of magnitude and direction of the Earth's magnetic field affected by the local structures of a corresponding building; and select a part of the indoor EMF map on the basis of the location estimate of the positioning device, wherein the selected part of the indoor magnetic field map includes the indoor EMF map for the area in which the positioning device currently is.

主权项

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 to, with the at least one processor, cause the apparatus at least to:
acquire an initial location estimate of a positioning device that is to determine its location inside a building, wherein the location estimate is acquired on the basis of an indoor non-magnetic field based location discovery system;access an indoor Earth's magnetic field, EMF, map for a plurality of floors of buildings, wherein the indoor EMF map represents magnitude and direction of the Earth's magnetic field affected by the local structures of a corresponding building;select at least one sub-part of the indoor EMF map on the basis of the acquired initial location estimate of the positioning device, wherein the at least one sub-part of the indoor EMF map selected is an area of the indoor EMF map corresponding to the acquired initial location estimate; andperform at least one of the following:
provide, on request, the selected at least one sub-part of the indoor EMF map to the positioning device in order to allow the positioning device to use the selected at least one sub-part of the indoor EMF map in locating itself; oracquire at least one measured EMF vector value from the positioning device, and apply the at least one measured EMF vector value and the selected at least one sub-part of the indoor EMF map in an indoor EMF map-based location determination of the positioning device.