MATCHING OF CROWDSOURCED BUILDING FLOORS WITH THE GROUND LEVEL

Abstract

A method is provided that includes obtaining or causing obtaining radiomap data representing at least a part of a structure. The radiomap data includes radiomap data acquired at least along a part of a first track comprising a first position at a reference altitude and a second position inside of the structure. The method also includes associating or causing associating the radiomap data of the second position with relative altitude information of the structure based on the reference altitude of the first position. A corresponding apparatus and computer program product are also provided.

Claims

1. A method performed by at least one apparatus, the method comprising: obtaining or causing obtaining radiomap data representing at least a part of a structure, the radiomap data comprising radiomap data acquired at least along a part of a first track comprising a first position at a reference altitude and a second position inside of the structure; and associating or causing associating the radiomap data of the second position with relative altitude information of the structure based on the reference altitude of the first position.

2. The method according to claim 1, wherein the radiomap data comprises at least two radiomap data layers respectively corresponding to a respective absolute altitude and/or to an absolute altitude range, one of the at least two radiomap data layers comprising the radiomap data of the second position, the method comprising: associating or causing associating at least a part of the radiomap data layer comprising the radiomap data of the second position with the relative altitude information of the structure based on the reference altitude of the first position.

3. The method according to claim 1, wherein the first position is determined to be at the reference altitude and the second position is determined to be inside of the structure based on at least one measurement result acquired with at least one sensor comprising at least one of a barometer; a gyroscope; an accelerometer; a motion sensor; a magnetometer; an audio sensor; a light sensor; a WLAN modem; or a Bluetooth Low Energy (BLE) modem.

4. The method according to claim 3, wherein the at least one sensor is comprised by a mobile device used at least for acquiring the radiomap data representing at least the part of the structure along said part of the first track comprising the first position and the second position.

5. The method according to claim 1, further comprising: determining the first position to be at the reference altitude and the second position to be inside of the structure based on a change in barometric pressure, an audio environment, a light environment, a signal strength of a WLAN or BLE signal between the first position and the second position.

6. The method according to claim 1, further comprising: associating or causing associating at least the radiomap data of the second position with map data of a geographic and/or geodetic system.

7. The method according to claim 2, wherein a radiomap data layer different from the radiomap data layer comprising the radiomap data of the second position comprises radiomap data acquired at least along a part of a second track comprising a third position inside of the structure and a fourth position, the method further comprising: if the first and the fourth positions are at a ground level of the structure, associating or causing associating at least the radiomap data of the third position and at least the radiomap data of the second position with same relative altitude information of the structure.

8. The method according to claim 7, further comprising: associating or causing associating at least the radiomap data of the second position and at least the radiomap data of the third position respectively with corresponding map data of a geographic and/or geodetic system.

9. The method according to claim 1, wherein the relative altitude information of the structure corresponds to a floor identifier identifying a respective floor level of the structure.

10. The method according to claim 1, wherein the first position is outside of the structure, wherein the reference altitude of the first position corresponds to a ground level of the structure, and wherein the associating or causing associating the radiomap data of the second position with relative altitude information of the structure associates the radiomap data of the second position with a floor identifier identifying a ground floor of the structure.

11. A method performed by at least one apparatus, the method comprising: obtaining or causing obtaining radio measurement data representative of a radio environment at a position of the at least one apparatus; obtaining or causing obtaining a position estimate of the at least one apparatus based on the radio measurement data and radio map data representing at least a part of a structure; wherein the radiomap data comprises radiomap data acquired at least along a part of a track comprising a first position at a reference altitude and a second position inside of the structure, wherein the second position is associated with relative altitude information of the structure based on the reference altitude of the first position.

12. The method according to claim 11, wherein the radiomap data comprises at least two radiomap data layers respectively corresponding to a respective absolute altitude and/or to an absolute altitude range, one of the at least two radiomap data layers comprising the radiomap data of the second position, wherein at least a part of the radiomap data layer comprising the radiomap data of the second position is associated with the relative altitude information of the structure based on the reference altitude of the first position.

13. The method according to claim 11, wherein at least the radiomap data of the second position is associated with map data of a geographic and/or geodetic system.

14. An apparatus comprising at least one processor and at least one memory that contains program code, wherein the memory and the program code are configured to use the at least one processor to cause an apparatus to perform and/or control at least: obtaining or causing obtaining radiomap data representing at least a part of a structure, the radiomap data comprising radiomap data acquired at least along a part of a first track comprising a first position at a reference altitude and a second position inside of the structure; and associating or causing associating the radiomap data of the second position with relative altitude information of the structure based on the reference altitude of the first position.

15. The apparatus according to claim 14, wherein the radiomap data comprises at least two radiomap data layers respectively corresponding to a respective absolute altitude and/or to an absolute altitude range, one of the at least two radiomap data layers comprising the radiomap data of the second position, and wherein the memory and the program code are configured to use the at least one processor to cause the apparatus to associate or cause association of at least a part of the radiomap data layer comprising the radiomap data of the second position with the relative altitude information of the structure based on the reference altitude of the first position.

16. The apparatus according to claim 14, wherein the memory and the program code are further configured to use the at least one processor to cause an apparatus to: determine the first position to be at the reference altitude and the second position to be inside of the structure based on a change in barometric pressure, an audio environment, a light environment, a signal strength of a WLAN or BLE signal between the first position and the second position.

17. The apparatus according to claim 14, wherein the memory and the program code are further configured to use the at least one processor to cause an apparatus to: associate or cause association of at least the radiomap data of the second position with map data of a geographic and/or geodetic system.

18. The apparatus according to claim 15, wherein a radiomap data layer different from the radiomap data layer comprising the radiomap data of the second position comprises radiomap data acquired at least along a part of a second track comprising a third position inside of the structure and a fourth position, and wherein the memory and the program code are further configured to use the at least one processor to cause an apparatus to: if the first and the fourth positions are at a ground level of the structure, associate or cause association of at least the radiomap data of the third position and at least the radiomap data of the second position with same relative altitude information of the structure.

19. The apparatus according to claim 18, wherein the memory and the program code are further configured to use the at least one processor to cause an apparatus to: associate or cause association of at least the radiomap data of the second position and at least the radiomap data of the third position respectively with corresponding map data of a geographic and/or geodetic system.

20. The apparatus according to claim 14, wherein the relative altitude information of the structure corresponds to a floor identifier identifying a respective floor level of the structure.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0112] FIG. 1 is a diagram of a system for performing exemplary embodiments of the invention;

[0113] FIG. 2A is a schematic illustration of a radio environment of a mobile device;

[0114] FIG. 2B is an exemplary illustration of a radiomap;

[0115] FIG. 3 is a block diagram of a server of FIG. 1 as an example of an apparatus according to the first aspect of the invention;

[0116] FIG. 4 is a block diagram of a mobile device of FIG. 1 as an example of an apparatus according to the second aspect of the invention;

[0117] FIG. 5A is a schematic side-view of a structure according to an exemplary embodiment;

[0118] FIG. 5B is a schematic side-view of a structure according to an exemplary embodiment;

[0119] FIG. 5C is a schematic side-view of a structure according to an exemplary embodiment;

[0120] FIG. 5D is a schematic top-view of a structure according to an exemplary embodiment;

[0121] FIG. 5E is a schematic top-view of a structure according to an exemplary embodiment;

[0122] FIG. 6A is a flow chart illustrating an example of a method according to the first aspect of the invention;

[0123] FIG. 6B is a flow chart illustrating an example of a method according to the second aspect of the invention; and

[0124] FIG. 7 is a schematic illustration of examples of tangible storage media according to the invention.

DETAILED DESCRIPTION OF THE FIGURES

[0125] The following description serves to deepen the understanding of the present invention and shall be understood to complement and be read together with the description of example embodiments of the invention as provided in the above SUMMARY section of this specification.

[0126] FIG. 1 is a diagram of a system 10 for performing exemplary embodiments of the invention. System 10 comprises a server 3 (an example of the at least one apparatus according to the first aspect of the invention, e.g. of a positioning server) and a mobile device 4 (an example of the at least one apparatus according to the second aspect of the invention). Mobile device 4 is illustrated exemplary moving along track 20 from a first position I to a fourth position IV for example while being outside (e.g. at first position I or at fourth position IV) and/or inside (e.g. at second position II or at third position III) of structure 2 (e.g. of a building). Mobile device 4 may move along said track 20 during a positioning procedure of mobile device 4 based on a radiomap of structure 2 and its closer vicinity (at least including positions I and IV) stored at mobile device 4 and/or at server 3. In an alternative example, mobile device 4 may move along track 20 during a crowdsourcing procedure for generating a radiomap of structure 2 (in this exemplary case, mobile device 4 may correspond to a further example of the at least one apparatus according to the first aspect). Reference numerals 5 and 8 indicate exemplary entrance/exit positions where mobile device 4 may enter/exit structure 2 when moving (e.g. being moved, carried by a user) along track 20. It is to be noted that the dashed line in between the second position II and the third position III of mobile device 4 indicates schematically that the part of the first track including the first position I and the second position II inside of structure 2 is on one floor of structure 2 and that the part of the second track including the third position III and the fourth position IV inside of structure 2 is on a different floor (e.g. above or below). In other words, mobile device 4 may enter structure 2 via entrance 8 on one floor which corresponds to a ground floor on the respective side of structure 2 and may leave structure 2 via entrance 5 on a floor which is a different floor of structure 2, however, also corresponds to a ground floor of structure 2 on the other side. Thereby, e.g. at a position schematically indicated by the dashed line between position II and position III, mobile device 4 may change the respective floors using stairs or an elevator (not shown in the figure).

[0127] When used in a crowdsourcing procedure, mobile device 4 may be used for collecting fingerprints of the radio environment (e.g. radio signals transmitted/broadcasted by wireless access points 6.1, 6.2, 6.3, 6.4) e.g. in and around structure 2. As mentioned above, wireless access points in accordance with embodiments of all aspects of the present invention correspond to or comprise Wireless Local Area Network, WLAN, access points, a Bluetooth access point; and/or an access point of a cellular communications network. Hereby, a cellular communications network may for example be a mobile phone network like a 2G/3G/4G/5G cellular communication network. The 2G/3G/4G/5G cellular radio communication standards are developed by the 3GPP and presently available under http://www.3gpp.org/.

[0128] When acquiring radiomap data for generating or supplementing a radiomap in a crowdsourcing procedure, acquired position information may be based on signals received from satellites 7 of a global navigation satellite system (GNSS). As such signals may only or primarily be available outside of structure 2 (in particular at positions I and IV), acquired position information may alternatively or additionally be based on sensors of the respective mobile device 4, such as a barometer, a motion sensor, an accelerometer, a magnetometer and/or a gyroscope. Fingerprints collected by mobile device 4 when moving along track 20 may be stored at mobile device 4 or may be communicated to server 3 (the communication being conceptually exemplarily indicated by dashed arrows in FIG. 1).

[0129] In an alternative example, track 20 may represent a track along which mobile device 4 moves while a position estimate of mobile device 4 obtained based on a radiomap of structure 2 and its vicinity and radio signals of wireless access points 6.1, 6.2, 6.3, 6.4 is acquired/obtained by mobile device 4 e.g. to be displayed on a display of mobile device 4 superimposed e.g. on an indoor map of structure 2.

[0130] Mobile device 4 may be enabled to communicate with server 3 via a wireless or a wired network connection (as exemplarily indicated by dashed arrows in the figure). As mentioned above, a wireless connection may correspond to a communication path or link in a wireless communication network, in particular a terrestrial wireless communication network like a Wireless Local Area Network (WLAN) or a cellular network. WLAN is for example specified by the standards of the IEEE 802.11 family (http://www.ieee.org/). A cellular network may for example be a mobile phone network like a 2G/3G/4G/5G cellular communication network. The 2G/3G/4G/5G cellular radio communication standards are developed by the 3GPP and presently available under http://www.3gpp.org/. A wireless connection may further include a Device-to-Device (D2D) communication path (e.g. involving vehicles, mobile devices, Road Side Units (RSU) or IOT devices).

[0131] Further, a wired connection may correspond to a communication path or link in a wired communication network employing wire-based communication technology and may correspond to a telephone network connection, a cable television connection, an internet connection, a fiber-optic connection or an electromagnetic waveguide connection.

[0132] In the example case shown in FIG. 1, mobile device 4 may be enabled to communicate with server 3 using any one of or all of wireless access points 6.1, 6.2, 6.3, 6.4 being connected to server 3 e.g. via a local area network and/or the Internet or via a cellular communication network.

[0133] FIG. 2A exemplarily illustrates a simplified radio environment of mobile device 4 within structure 2 which may be used to estimate a position of mobile device 4, e.g. to obtain an estimate of the position of mobile device 4 in horizontal coordinates in longitudinal and latitudinal directions (x and y directions shown in FIG. 2A). For conciseness, only simplified radio signal ranges C1, C2, C3 of wireless access points 6.1, 6.2, 6.3 are illustrated (the topology being simplified), the radio signal ranges simplified as overlapping circles. FIG. 2A illustrates areas, where respective radio signal ranges mutually overlap, i.e. area C12 where radio signal ranges C1 and C2 overlap, area C23 where radio signal ranges C2 and C3 overlap, area C13, where radio signal ranges C1 and C3 overlap and area C123, where radio signal ranges C1, C2 and C3 overlap. As can be taken from FIG. 2A, when mobile device 4 acquires identification information of all wireless access points 6.1, 6.2, 6.3, based on the corresponding identification information, a position of mobile device 4 can be estimated to be within the area of overlap C123. Similarly, if mobile device 4 would require only identification information of wireless access points 6.1 and 6.2, a position of mobile device 4 could be estimated to be within an area of overlap C12.

[0134] As disclosed above, measurements of the radio environment when for example moving along track 20 as shown in FIG. 1 can also be used by mobile device 4 for building a new or for supplementing an existing radiomap. To this end, mobile device 4 may obtain identification information of wireless access points from which mobile device 4 receives radio signals based on the received radio signals and may associate the obtained identification information with position information of the position where mobile device 4 has received the radio signals. Position information of said position may be obtained by mobile device 4 for example using signals of GNSS satellites 7 (in particular when outdoors, e.g. when at the first position I or the fourth position IV). In particular when moving indoors (e.g. when at the second position II illustrated in FIG. 2A), such position information may be obtained in based on sensors of the mobile device 4, such as a barometer, a motion sensor, an accelerometer, a magnetometer and/or a gyroscope. FIG. 2B illustrates an exemplary non-limiting representation of a radiomap which may represent an indoor area of structure 2 of FIG. 1. As shown, identification information of wireless access points 6.1, 6.2, 6.3, 6.4, i.e. corresponding IDs (ID6.1, ID6.2, ID6.3, ID6.4) are stored (either at mobile device 4 and/or at server 3) in association with position information of positions where radio signals of the respective wireless access points are receivable. In the shown case, position information corresponds to horizontal coordinates in longitudinal and latitudinal directions. In the shown example, for example coordinates x.sub.i.sup.C.sup.1, y.sub.i.sup.C.sup.1 are x, y coordinates representative of positions i where radio signals from wireless access point 6.1 are receivable. Similarly, x.sub.i.sup.C.sup.j, y.sub.i.sup.C.sup.j are x, y coordinates representative of positions i where radio signals from wireless access point 6.j are receivable.

[0135] As mentioned, the concept illustrated using FIG. 2A and FIG. 2B is simplified and only intended to illustrate the concept. In addition to identification information, radio quality information, for example Received Signal Strength Indication, RSSI, and/or path loss information may further be stored with respective fingerprints. In such case, a fingerprint may further comprise z-information (representative e.g. of RSSI, and/or path loss information) and a single wireless access point may have a cone-shaped radiomap where a high signal strength may be associated with a small distance from the access point (large z-value at x, y=0) and where signal strength decreases with distance from the wireless access point. Thus, if upon positioning, a fingerprint is received by mobile device 4, such fingerprint may comprise identification information of three wireless access points and three corresponding RSSI-values. The additional RSSI information may be used to obtain a position estimate with higher accuracy.

[0136] FIG. 3 is a block diagram of server 3 of FIG. 1 as an example of the at least one apparatus according to the first aspect of the invention.

[0137] Server 3 comprises a processor 31. Processor 31 may represent a single processor or two or more processors, which are for instance at least partially coupled, for instance via a bus. Processor 31 may use program memory 32 and main memory 33 to execute a program code stored in program memory 32 (for instance program code causing server 3 to perform embodiments of the different methods, when executed on or by processor 31). Some or all of memories 32 and 33 may also be included into processor 31. One of or both of memories 32 and 33 may be fixedly connected to processor 31 or at least partially removable from processor 31. Program memory 32 may for instance be a non-volatile memory. It may for instance be a FLASH memory, any of a ROM, PROM, EPROM and EEPROM memory or a hard disc, to name but a few examples. Program memory 32 may also comprise an operating system for processor 31. Main memory 33 may for instance be a volatile memory. It may for instance be a RAM or DRAM memory, to give but a few non-limiting examples. It may for instance be used as a working memory for processor 31 when executing an operating system and/or programs.

[0138] Processor 31 further controls one or more communication interfaces 34 configured to receive and/or send information. For instance, server 3 may be configured to communicate with mobile device 4 of system 10 of FIG. 1 (corresponding to mobile device 4 of FIG. 2A). Such a communication may for instance comprise receiving collected fingerprints, i.e. in particular access point identification information (e.g. ID6.1, ID6.2, ID6.3, ID6.4) and optionally signal quality information (e.g. corresponding RSSI values and/or path loss information for radio signals received from each respective wireless access point), from mobile device 4. Also, server 3 may be able to send e.g. a determined radiomap and/or a determined position estimate of mobile device 4 to mobile device 4 for the purpose of positioning of mobile device 4. The communication may for instance be based on a (e.g. partly) wireless connection. The communication interface 34 may thus comprise circuitry such as modulators, filters, mixers, switches and/or one or more antennas to allow transmission and/or reception of signals. In embodiments of the invention, communication interface 34 is inter alia configured to allow communication according to a 2G/3G/4G/5G cellular communication system and/or a non-cellular communication system, such as for instance a WLAN network and/or a Bluetooth network.

[0139] Processor 31 further interfaces with a mass storage 35, which may be part of the server 3 or remote from server 3, and which may for instance be used to store one or more databases. For instance, server 3 may store, in a database, collected fingerprints collected by mobile device 4. Further, server 3 may store in a database indoor map data and/or radiomap data corresponding to one or more radiomaps e.g. including a radiomap representative of one or more floors of structure 2.

[0140] The components 32-35 of server 3 may for instance be connected with processor 31 by means of one or more serial and/or parallel busses.

[0141] FIG. 4 is a block diagram of mobile device 4 of FIG. 1 as an example of the at least one apparatus according to the second aspect of the invention.

[0142] Mobile device 4 comprises a processor 41. Processor 41 may represent a single processor or two or more processors, which are for instance at least partially coupled, for instance via a bus. Processor 41 may use program memory 42 and main memory 43 to execute a program code stored in program memory 42 (for instance program code causing mobile device 4 to perform embodiments of the different methods, when executed on processor 41). Some or all of memories 42 and 43 may also be included into processor 41. One of or both of memories 42 and 43 may be fixedly connected to processor 41 or at least partially removable from processor 41. Program memory 42 may for instance be a non-volatile memory. It may for instance be a FLASH memory, any of a ROM, PROM, EPROM and EEPROM memory or a hard disc, to name but a few examples. Program memory 42 may also comprise an operating system for processor 41. Main memory 43 may for instance be a volatile memory. It may for instance be a RAM or DRAM memory, to give but a few non-limiting examples. It may for instance be used as a working memory for processor 41 when executing an operating system and/or programs.

[0143] Processor 41 further controls one or more communication interfaces 44 configured to receive and/or send information. For instance, mobile device 4 may be configured to communicate with sever 4 of system 10 of FIG. 1. Such a communication may for instance comprise providing (transmitting) collected fingerprints from mobile device 4 to server 3. Also, mobile device 4 may be able to receive e.g. a radiomap or a determined position estimate of mobile device 4 from server 3 for the purpose of positioning. The communication may for instance be based on a (e.g. partly) wireless connection. The communication interface 44 may thus comprise circuitry such as modulators, filters, mixers, switches and/or one or more antennas to allow transmission and/or reception of radio signals. In embodiments of the invention, communication interface 44 is inter alia configured to allow communication according to a 2G/3G/4G/5G cellular communication system and/or a non-cellular communication system, such as for instance a WLAN network and/or a Bluetooth network.

[0144] Processor 41 further controls a user interface 45 configured to present information to a user of mobile device 4 to receive information from such a user, such as manually input position fixes, a site map or floor plan of the area or the like. User interface 44 may for instance be the standard user interface via which a user of mobile device 4 controls other functionality thereof, such as making phone calls, browsing the Internet, etc.

[0145] Processor 41 may further control a GNSS interface 46 configured to receive position information of a GNSS such as Global Positioning System (GPS), Galileo, Global Navigation Satellite System (i.e. Globalnaja Nawigazionnaja Sputnikowaj a Sistema, GLONASS) or Quasi-Zenith Satellite System (QZSS). In case of mobile device 4, the location information of GNSS interface 46 (potentially in connection with further sensors of mobile device 4, such as an inertial sensor, an accelerometer or gyroscope) may be used in order to obtain position information. Mobile device 4 may utilize GNSS interface 46 to communicate with GNSS satellites 7 of FIG. 1.

[0146] The components 42-46 of mobile device 4 may for instance be connected with processor 41 by means of one or more serial and/or parallel busses.

[0147] FIGS. 5A to 5E exemplarily illustrate structure 2 in exemplary embodiments. FIG. 5A exemplarily illustrates structure 2 where a radiomap of structure 2 has been acquired for example in a crowdsourcing procedure by a plurality of mobile devices that have moved around the different floors of structure 2 while collecting fingerprints of the radio environment of structure 2. As exemplarily shown, the corresponding radiomap of structure 2 has been structured into individual layers of radiomap data denoted in the figure as layers L0 to L4 where layer L0 corresponds to a basement of structure 4 and layer L1 corresponds to a ground floor of structure 2. FIG. 5A illustrates a case where user 1 enters structure 2 using entrance 5 on the ground floor and proceeds to the first floor above the ground floor, this first floor corresponding to the radiomap data layer L2.

[0148] As explained in detail above, by analyzing tracks included in radiomap data, it is possible to find tracks with outdoors/indoors transition(s) such as the track of user 1 in FIG. 5A. Such analysis enables determining matches between the ground level (outside of structure 2), a corresponding ground floor of the structure and of a corresponding radiomap data layer which in the case shown in FIG. 5A corresponds to radiomap data layer L1. As further explained in more detail above, one option to detect an indoor/outdoor transition is to analyze sensor data acquired by a mobile device moving along such track in combination with fingerprints acquired by the mobile device while moving along this track. For example, an option is to analyze barometer (pressure) readings of the mobile device while moving along the track. As explained above, in particular multi-story buildings may have air conditioning, which may cause pressure within the building to be lower than pressure outside of the building. A change in air pressure along a track may thus be an indication of an indoor/outdoor transition along this track. An additional option to identify a track with an indoor/outdoor transition is to analyze sensor data of further sensors such as accelerometers, to detect for example if a userafter entering a buildingstayed on the ground level for some time.

[0149] Referring back to FIG. 5A, user 1 moves along the track indicated with the arrow from a position outside of structure 2 to a position on the first floor above the ground floor, this floor corresponding to radio data layer L2. User 1 may carry a mobile device used for a crowdsourcing procedure, i.e. for acquiring radiomap data (e.g. fingerprints) while moving along this track. In a later analysis, data acquired along this track may be used to match radio data layer L1 to the ground floor of structure 2.

[0150] FIG. 5B illustrates the structure 2 of FIG. 5A assuming that crowdsourcing has already taken place and that a radiomap corresponding to structure 2 exists, this radiomap being structured into layers L0 to L4 as in case of FIG. 5A. In the case shown in FIG. 5A, a person 1 is for example at his or her office room. When position estimate is calculated for person 1 e.g. based on the radio environment, it can be derived from this position estimate that person 1 is on layer L3 of the radiomap data. In case the above described analysis has already been performed and the radiomap data layers L0 to L4 have been associated to the real world floors of structure 2 with reference to the ground floor, it can be determined based on the so associated radiomap data that person 1 is at a floor which is two floors above the ground level. It becomes thus possible that for example when person 1 is in an emergency situation and makes an emergency call, the person 1 can be located based on the radio signals to reside at layer L3, and the call center can instruct the first responders to look for the person at a floor which is two floors above the ground level.

[0151] FIG. 5C illustrates the situation of FIG. 1, wherein a ground level at the first position I is different from a ground level of the fourth position IV. As shown, at the first position I near entrance 8, the ground floor corresponds to radio data layer L2 while at the fourth position IV near entrance 5, the ground floor corresponds to radio data layer in L1. As explained above, the present invention enables associating a ground floor of a structure 2 also in such situations where the ground around a building is a raked surface, and hence the ground level on different sides of the building matches with different building floors.

[0152] In particular in this kind of a case, when the aim is to express a relative floor indication with respect to the ground level, it is useful that a local radiomap of structure 2 (i.e. the crowdsourced radiomap data layers L0 to L4) may further be associated with a global coordinate system such as the WGS-84 system, for example with support of a GNSS system, e.g. using GNSS satellites 7 shown in FIG. 1. As a result, position information at the side of structure 2 e.g. corresponding to radiomap data of the second position II and position information at the opposing side of structure 2 e.g. corresponding to radiomap data of the third position III may be respectively expressed in a global coordinate system. FIG. 5D shows a top view of the situation depicted in side-view in FIG. 5C and in FIG. 1, where the local radiomap of structure 2 is associated with a global coordinate system as indicated by the compass. Given this, if a person in structure 2 makes an emergency call, he or she can be located based on the radio signals e.g. to reside for example at layer L3 of structure 2 of FIG. 5B (structure 2 on the raked surface). Given the additional information based on the global coordinate system as indicated in FIG. 5D, the call center can instruct the first responders to look for the person at e.g. a floor which is two floors above the ground level in case they arrive in the building from the South-East side (see FIG. 5D), or one floor above the ground level in case they arrive in the building from North-West side (see FIG. 5D).

[0153] As further illustrated in FIG. 5E, association of the local radiomap of structure 2 with said global coordinate system offers further possibilities that may help to enable fast location of the person in particular in emergency cases. As a further possibility, due to associating the radiomap of the building with respect to a global coordinate system, it is possible to place the radiomap on a real world map, and to identify for example the streets which are adjacent to the radiomap (i.e. adjacent to the building). Hence, similar to the case discussed in relation to FIG. 5D, as illustrated in FIG. 5E, it is possible to identify that the radiomap at the side of the first position I and the second position II is adjacent to the Victory Street, and that the radiomap at the side of the third position III and the fourth position IV is adjacent to the Main Street. As an example, if a person in the building makes an emergency call, he or she can be located based on radio signals (e.g. of wireless access points 6.1, 6.2, 6.3, 6.4) to be for example at layer L3 of structure 2 on the raked surface (see FIG. 5C), and the call center can instruct the first responders to look for the person at a floor which is two floors above the ground level in case they arrive in the building from the Main Street, or one floor above the ground level in case they arrive in the building from the Victory Street.

[0154] The methods of the different aspects will now be described in more detail with respect to FIGS. 6A and 6B.

[0155] FIG. 6A is a flowchart 610 illustrating an example of a method according to the first aspect of the invention. Without limiting the scope of the invention, it is assumed in the following that server 3 (an example of the at least one apparatus according to the first aspect of the present invention) as disclosed above with respect to system 10 of FIG. 1 performs the steps of flowchart 610. It is to be understood that any step of flow chart 610 may be performed by any one or more than one apparatus (e.g. one or more processors of server 3 and/or one or more servers). Further, in a second alternative example of the first aspect the steps of flowchart 610 can be performed by a mobile device which is for example configured to analyze radiomap data stored at the mobile device to determine tracks that include outdoors/indoors transitions and that thus is configured to find matches between a ground floor of a building and a corresponding layer of radiomap data as disclosed above. Still further, in a third alternative example of the first aspect, the steps of flow chart 610 can be performed by a mobile device when collecting/acquiring radiomap data for generating new or supplementing existing radiomap data.

[0156] In step 611, server 3 obtains radiomap data representing at least part of a structure, e.g. of structure 2 of FIG. 1. Server 3 may for example obtain radiomap data stored at a corresponding memory of server 3 which has been previously acquired by one or more mobile devices e.g. in a crowdsourcing procedure. Thereby, the obtained radiomap data comprises (at least) radiomap data acquired at least along part of a first track including the first position at a reference altitude and the second position inside of the structure. Said radiomap data acquired along at least part of said first track may correspond to radiomap data acquired by a mobile device e.g. during said crowdsourcing procedure.

[0157] In step 612, server 3 associates (or e.g. one or more processors cause server 3 to associate) the radiomap data of the second position with relative altitude information of the structure based on the reference altitude of the first position. In this step, the radiomap data of the second position, e.g. a fingerprint acquired by a mobile device during a crowdsourcing procedure at this position, is associated (e.g. stored in combination with or with reference to) with said relative altitude information of the structure. For example, if the first position is a position outside of the structure such as position I of FIG. 1 outside of structure 2, the relative altitude information of the structure based on the reference altitude of the first position may be e.g. a floor indicator indicating the ground floor of the structure (e.g. 0, 1, ground, or the like).

[0158] As discussed above in relation to FIGS. 5A to 5E, by associating a radiomap data layer corresponding to the ground floor of a structure with corresponding relative altitude information with reference to said ground floor, it becomes possible to identify different layers of the radiomap data (e.g. simply by counting from said layer associated with the ground floor) with relative altitude information based on the ground floor of the structure (for example third layer above ground floor).

[0159] FIG. 6B is a flowchart 620 illustrating an example of a method according to the second aspect of the invention. Without limiting the scope of the invention, it is assumed in the following that mobile device 4 (an example of the at least one apparatus according to the second aspect of the present invention) as disclosed above with respect to system 10 of FIG. 1 performs the steps of flowchart 620. It is to be understood that any step of flow chart 620 may be performed by any one or more than one apparatus (e.g. one or more processors of mobile device 4). For example, the steps of flow chart 620 may be performed by mobile device 4 while performing positioning (while estimates of its position are obtained) based on measurements of a radio environment (e.g. the radio environment of structure 2 of FIG. 1) and based on corresponding radiomap data which has been generated previously by one or more mobile devices acquiring corresponding radiomap data for example of structure 2 e.g. in a crowdsourcing procedure.

[0160] In step 621, mobile device 4 obtains (or one or more processors of mobile device 4 cause mobile device 4 to obtain) radio measurement data representative of a radio environment at a position of mobile device 4. For example, when located at position II in FIG. 1, mobile device 4 may measure radio signals transmitted from wireless access points 6.1, 6.2 and 6.3 and may obtain for example identification information of said wireless access points (ID6.1, ID6.2, ID6.3) based on the measured radio signals. By relating the obtained identification information to a radiomap stored for example at mobile device 4, as illustrated in FIG. 2A, mobile device 4 may be found to be positioned within an area C123. The obtained measurement results, i.e. the obtained identification information, may similarly be communicated by mobile device 4 to server 3 to be related to a radiomap stored at server 3.

[0161] Thus, in step 622, mobile device 4 obtains (or one or more processors of mobile device 4 cause mobile device 4 to obtain) a position estimate (indicating that mobile device 4 is for example at a location within said area C123) of the mobile device 4 based on the radio measurement data and radiomap data representing at least part of the structure. Thereby, the radiomap data comprises radiomap data acquired at least along part of a track including the first position at a reference altitude and the second position inside of the structure. As discussed in more detail above, said track may correspond to a track along which a mobile device has moved while acquiring radiomap data for generating or supplementing the radiomap based on which mobile device 4 is positioned (based on which a position estimate of mobile device 4 for is obtained) in step 622. Thereby, as discussed above, the second position is associated with relative altitude information of the structure based on the reference altitude of the first position. In other words, if the first position is a position outside of the structure (such as position I in case of structure 2 in FIG. 1), the second position is associated with relative altitude information indicating a ground level of the structure. Thus, when a position estimate is obtained of mobile device 4 based on the radiomap data including such association of the radiomap data with relative altitude information of the structure based on the reference altitude of the first position, in addition to horizontal position information and absolute altitude information such position estimate further includes information that allows to deduce on which mobile device 4 is located when the position estimate is obtained. It is possible for example to determine that the mobile device 4 is on floor x above or below a ground floor of structure 2.

[0162] It is thus possible not only to create radio signal based layer models for structures such as buildings by map data crowdsourcing, but also to associate such layers with respect to the ground level of a building without manual input required by users even when crowdsourcing is performed in massive scale. Such association of radiomap data layers with relative altitude information of structures can be utilized when locating mobile devices (when obtaining position estimates of mobile devices) based on radiomap data including such associations to discover the floor level relative to the ground level where the mobile devices reside. This can be very useful in particular in cases like emergency cases when police or firemen need to be guided to a certain floor in a building and where absolute altitude information is of limited use.

[0163] FIG. 7 is a schematic illustration of examples of tangible and non-transitory computer-readable storage media according to the present invention that may for instance be used to implement memory 32 of FIG. 3 or memory 42 of FIG. 4. To this end, FIG. 7 displays a flash memory 700, which may for instance be soldered or bonded to a printed circuit board, a solid-state drive 701 comprising a plurality of memory chips (e.g. Flash memory chips), a magnetic hard drive 702, a Secure Digital (SD) card 703, a Universal Serial Bus (USB) memory stick 704, an optical storage medium 705 (such as for instance a CD-ROM or DVD) and a magnetic storage medium 706.

[0164] The following example embodiments of the invention are also disclosed:

Embodiment 1

[0165] A method performed by at least one apparatus, in particular by at least one server and/or by at least one mobile device, the method comprising: [0166] obtaining or causing obtaining radiomap data representing at least a part of a structure, in particular a building, the radiomap data comprising radiomap data acquired at least along a part of a first track comprising a first position at a reference altitude and a second position inside of the structure (e.g. the building); [0167] associating or causing associating the radiomap data of, in particular acquired at, the second position with relative altitude information of the structure (e.g. the building), in particular a floor index/indicator, based on the reference altitude of the first position.

Embodiment 2

[0168] The method according to embodiment 1, wherein the radiomap data acquired at least along the part of the first track corresponds to radiomap data acquired by a mobile device moved, in particular by a user of the mobile device, along the first track when collecting at least part of the radiomap data representing the at least part of the structure, in particular in a crowdsourcing procedure.

Embodiment 3

[0169] The method according to any of embodiments 1 or 2, wherein the radiomap data comprises at least two radiomap data layers respectively corresponding to a respective absolute altitude and/or to an absolute altitude range, one of the at least two radiomap data layers comprising the radiomap data of the second position, the method comprising: [0170] associating or causing associating at least a part of the radiomap data layer comprising the radiomap data of the second position with the relative altitude information of the structure based on the reference altitude of the first position.

Embodiment 4

[0171] The method according to any of the preceding embodiments, wherein the first position is outside of the structure, and wherein the relative altitude information of the structure based on the reference altitude of the first position corresponds to an indication, e.g. a floor index/indicator, that indicates the second position to be on a ground floor of the structure and/or the radiomap data of the second position to be comprised by a layer of radiomap data corresponding to the ground floor of the structure.

Embodiment 5

[0172] The method according to any of the preceding embodiments, wherein the radiomap data comprises at least one fingerprint, the at least one fingerprint comprising position information of a position of the at least one fingerprint and at least one measurement result of at least one radio signal observable at the position of the fingerprint.

Embodiment 6

[0173] The method according to embodiment 5, wherein the position of the at least one fingerprint is a position at which the at least one fingerprint has been acquired by a mobile device when collecting at least part of the radiomap data representing the at least part of the structure.

Embodiment 7

[0174] The method according to any of embodiments 5 or 6, wherein the first track corresponds to a subset of the radiomap data, the subset comprising at least one fingerprint of/acquired at the first position and one fingerprint of/acquired at the second position.

Embodiment 8

[0175] The method according to embodiment 7, wherein the subset comprises fingerprints of/acquired at a plurality of positions of the first track.

Embodiment 9

[0176] The method according to any of embodiments 5 to 8, wherein the position information comprises horizontal position information (in particular data representative of coordinates in longitude and latitude directions) and/or vertical position information (in particular data representative of an absolute altitude).

Embodiment 10

[0177] The method according to any of embodiments 5 to 9, wherein the measurement result of a radio signal comprises identification information (in particular SSID and/or a MAC address) of a wireless access point transmitting (in particular broadcasting) the respective radio signal and/or signal quality information (in particular RSSI and/or a path loss indicator) of the radio signal observable at the position of the fingerprint.

Embodiment 11

[0178] The method according to any of the preceding embodiments, wherein the first position is determined to be at the reference altitude and the second position is determined to be inside of the structure based on at least one measurement result acquired with at least one sensor comprising at least one of a barometer; [0179] a gyroscope; [0180] an accelerometer; [0181] a motion sensor; [0182] a magnetometer; [0183] an audio sensor; [0184] a light sensor; [0185] a WLAN modem; [0186] a Bluetooth Low Energy (BLE) modem.

Embodiment 12

[0187] The method according to embodiment 11, wherein the at least one sensor is comprised by a mobile device used at least for acquiring the radiomap data representing at least the part of the structure along said part of the first track comprising the first position and the second position.

Embodiment 13

[0188] The method according to any of embodiments 11 to 12, wherein the at least one fingerprint further comprises a measurement result of at least one of the barometer; [0189] the gyroscope; [0190] the accelerometer; [0191] the motion sensor; [0192] the magnetometer; [0193] the audio sensor; [0194] the light sensor; [0195] the WLAN modem; [0196] the Bluetooth Low Energy (BLE) modem.

Embodiment 14

[0197] The method according to any of the preceding embodiments, further comprising: [0198] determining the first position to be at the reference altitude and the second position to be inside of the structure based on a change in barometric pressure, an audio environment, a light environment, a signal strength of a WLAN or BLE signal between the first position and the second position.

Embodiment 15

[0199] The method according to any of the preceding embodiments, further comprising: [0200] associating or causing associating at least the radiomap data of the second position with map data of a geographic and/or geodetic system.

Embodiment 16

[0201] The method according to embodiment 15, wherein the geodetic system is a WGS-84 system.

Embodiment 17

[0202] The method according to any of embodiments 2 to 16, wherein a radiomap data layer different from the radiomap data layer comprising the radiomap data of the second position comprises radiomap data acquired at least along a part of a second track comprising a third position inside of the structure and a fourth position, the method further comprising: [0203] if the first and the fourth position are at a ground level of the structure, associating or causing associating at least the radiomap data of the third position and at least the radiomap data of the second position with same relative altitude information of the structure.

Embodiment 18

[0204] The method according to embodiment 17, wherein the radiomap data acquired at least along the part of the second track corresponds to radiomap data acquired by a mobile device moved, in particular by a user of the mobile device, along the second track when collecting at least part of the radiomap data representing the at least part of the structure, in particular in a crowdsourcing procedure.

Embodiment 19

[0205] The method according to any of embodiments 17 or 18, wherein the second track corresponds to a subset of the radiomap data, the subset comprising at least one fingerprint of/acquired at the third position and one fingerprint of/acquired at the fourth position.

Embodiment 20

[0206] The method according to embodiment 19, wherein the subset comprises fingerprints of/acquired at a plurality of positions of the second track.

Embodiment 21

[0207] The method according to any of embodiments 17 to 20, further comprising: [0208] associating or causing associating at least the radiomap data of the second position and at least the radiomap data of the third position respectively with corresponding map data of a geographic and/or geodetic system.

Embodiment 22

[0209] The method according to embodiment 21, wherein the geodetic system is a WGS-84 system.

Embodiment 23

[0210] The method according to any of the preceding embodiments, wherein the relative altitude information of the structure corresponds to a floor identifier identifying a respective floor level of the structure.

Embodiment 24

[0211] The method according to any of the preceding embodiments, wherein the first position is outside of the structure, wherein the reference altitude of the first position corresponds to a ground level of the structure, and wherein the associating or causing associating the radiomap data of the second position with relative altitude information of the structure associates the radiomap data of the second position with a floor identifier identifying a ground floor of the structure.

Embodiment 25

[0212] The method according to any of embodiments 17 to 24, wherein the fourth position is outside of the structure, and wherein the associating or causing associating at least the radiomap data of the third position and at least the radiomap data of the second position with same relative altitude information of the structure associates the radiomap data of the second position and the radiomap data of the third position with a floor identifier identifying a ground level of the structure.

Embodiment 26

[0213] The method according to any of the preceding embodiments, wherein the/a mobile device is an Internet-of-Things (IoT) device, a smart home device, a smartphone, a tablet computer, a notebook computer, a smart watch, and a smart band.

Embodiment 27

[0214] The method according to any of embodiments 10 to 25, wherein the wireless access point corresponds to or comprises at least one of: [0215] a Wireless Local Area Network, WLAN, access point; [0216] a Bluetooth access point; or [0217] an access point of a cellular communications network.

Embodiment 28

[0218] A method performed by at least one apparatus, the method comprising: [0219] obtaining or causing obtaining radio measurement data representative of a radio environment at a position of the at least one apparatus; [0220] obtaining or causing obtaining a position estimate of the at least one apparatus based on the radio measurement data and radio map data representing at least a part of a structure;
wherein the radiomap data comprises radiomap data acquired at least along a part of a track comprising a first position at a reference altitude and a second position inside of the structure, wherein the second position is associated with relative altitude information of the structure based on the reference altitude of the first position.

Embodiment 29

[0221] The method according to embodiment 28, wherein the at least one apparatus is a mobile device, in particular an Internet-of-Things (IoT) device, a smart home device, a smartphone, a tablet computer, a notebook computer, a smart watch, and a smart band.

Embodiment 30

[0222] The method according to any of embodiments 28 or 29, wherein obtaining or causing obtaining the position estimate of the at least one apparatus comprises: [0223] relating or causing relating the radio measurement data to the radio map data representing at least a part of a structure stored at a memory of the at least one apparatus.

Embodiment 31

[0224] The method according to any of embodiments 28 or 29, wherein obtaining or causing obtaining the The method according to any of embodiments 28 or 29, wherein obtaining or causing obtaining the position estimate of the at least one apparatus comprises: [0225] communicating or causing communicating the radio measurement data to at least one server via a wired or a wireless connection to be related to radiomap data representing at least a part of a structure stored at a memory of the at least one server.

Embodiment 32

[0226] The method according to any of embodiments 28 to 31, wherein the radiomap data comprises at least two radiomap data layers respectively corresponding to a respective absolute altitude and/or to an absolute altitude range, one of the at least two radiomap data layers comprising the radiomap data of the second position, wherein at least a part of the radiomap data layer comprising the radiomap data of the second position is associated with the relative altitude information of the structure based on the reference altitude of the first position.

Embodiment 33

[0227] The method according to any of embodiments 28 to 32, wherein at least the radiomap data of the second position is associated with map data of a geographic and/or geodetic system.

Embodiment 34

[0228] The method according to embodiment 33, wherein the geodetic system is a WGS-84 system.

[0229] Any presented connection in the described embodiments is to be understood in a way that the involved components are operationally coupled. Thus, the connections can be direct or indirect with any number or combination of intervening elements, and there may be merely a functional relationship between the components.

[0230] Further, as used in this text, the term circuitry refers to any of the following:

[0231] (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry)

[0232] (b) combinations of circuits and software (and/or firmware), such as: (1) to a combination of processor(s) or (2) to sections of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile device, to perform various functions) and

[0233] (c) to circuits, such as a microprocessor(s) or a section of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present.

[0234] This definition of circuitry applies to all uses of this term in this text, including in any claims. As a further example, as used in this text, the term circuitry also covers an implementation of merely a processor (or multiple processors) or section of a processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example, a baseband integrated circuit or applications processor integrated circuit for a mobile phone.

[0235] Any of the processors mentioned in this text could be a processor of any suitable type. Any processor may comprise but is not limited to one or more microprocessors, one or more processor(s) with accompanying digital signal processor(s), one or more processor(s) without accompanying digital signal processor(s), one or more special-purpose computer chips, one or more field-programmable gate arrays (FPGAS), one or more controllers, one or more application-specific integrated circuits (ASICS), or one or more computer(s). The relevant structure/hardware has been programmed in such a way to carry out the described function.

[0236] Moreover, any of the actions or steps described or illustrated herein may be implemented using executable instructions in a general-purpose or special-purpose processor and stored on a computer-readable storage medium (e.g., disk, memory, or the like) to be executed by such a processor. References to computer-readable storage medium should be understood to encompass specialized circuits such as FPGAs, ASICs, signal processing devices, and other devices.

[0237] The wording A, or B, or C, or a combination thereof or at least one of A, B and C may be understood to be not exhaustive and to include at least the following: (1) A, or (2) B, or (3) C, or (4) A and B, or (5) A and C, or (6) B and C, or (7) A and B and C.

[0238] It will be understood that all presented embodiments are only exemplary, and that any feature presented for a particular exemplary embodiment may be used with any aspect of the invention on its own or in combination with any feature presented for the same or another particular exemplary embodiment and/or in combination with any other feature not mentioned. It will further be understood that any feature presented for an example embodiment in a particular category may also be used in a corresponding manner in an example embodiment of any other category.