POSITION DETERMINATION DEVICE AND PROCEDURES

Abstract

Positioning device comprising the following: - a data input circuit (21) configured to receive at least one magnetic field vector detected by a magnetic field sensor (10), - a data processor circuit (22) configured to determine the magnetic field magnitude and an additional magnetic field parameter of the at least one obtained magnetic field vector, - a comparison circuit (23) configured to compare the determined magnetic field quantity with a predetermined magnetic field quantity map of an area around the magnetic field sensor to obtain a first estimate of the sensor position, and to compare the determined additional magnetic field parameter with a corresponding predetermined map of the additional parameter of an area around the magnetic field sensor to obtain a second estimate of the sensor position, - a weighting determination circuit (24) configured to determine weighting information indicating the reliability of the first and / or second estimate of the sensor position and / or the relative weighting of the first estimate with respect to the second estimate, wherein the weighting information is determined based on the local variation in a local sensor area of ​​the magnetic field size in the magnetic field size map and / or the additional magnetic field parameter in the additional parameter map, and - a position determination circuit (25) configured to weight the first and second estimates of the sensor position according to the specified weighting information and to determine the sensor position from the weighted first and second estimates.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to European application 15185520.2, filed on 16 September 2015, the contents of which are incorporated herein by reference in their entirety BACKGROUND OF REVELATION

[0002] The present disclosure relates to a positioning device and a corresponding positioning method for determining the position of the device, particularly indoors. The present disclosure further relates to a mobile device and a non-transitory computer-readable recording medium. DESCRIPTION OF THE STATE OF THE ART

[0003] Many technologies are being researched for indoor positioning (especially location determination and / or navigation). Geomagnetic fingerprinting technology exploits the fact that the magnetic field inside buildings is distorted in a unique way by the building's construction (material). The idea is to collect magnetic field maps of the building (offline phase), which can later be used for navigation (online phase) in such a way that current magnetic field measurements are matched against the mapped magnetic field profile (fingerprints). The more components a fingerprint contains, the more unique its evaluation; conversely, the fewer components a fingerprint has, the more matches will be found in the fingerprint map. Of course, a magnetic field map of a building can contain many duplicates or at least similar entries.

[0004] The Earth's magnetic field is a 3-dimensional vector (i.e., it has x, y, and z components), which in principle allows for the generation of 3-dimensional fingerprints. However, since the measurements depend on the orientation of the magnetic field sensor, which cannot be detected or can only be partially detected (e.g., using an accelerometer), only one magnetic field component (e.g., magnitude) or only two components (e.g., vertical and horizontal components) can generally be used as a fingerprint.

[0005] The description of "Background" provided herein is for the purpose of generally presenting the context of this disclosure. Work by the presently named inventor(s) to the extent described in this Background section, as well as aspects of the description that may not otherwise be considered prior art at the time of filing, are not expressly or impliedly incorporated as prior art to the present disclosure. US 2015 / 0 153 151 A1 discloses systems and methods for determining location using magnetic fields from AC power lines. For example, each magnetic field measurement acquired by the device over time can be analyzed to determine a variety of properties of the magnetic field.One or more of the plurality of properties may describe a component of the magnetic field oscillating at a frequency associated with the AC power lines. The plurality of properties may be compared to expected values, each associated with a plurality of locations, provided by a map of the magnetic field to determine a location where each magnetic field measurement was taken. In further embodiments, magnetic field measurements taken by the device over time may be analyzed in conjunction with other data or constraints to determine a trajectory of the device. Furthermore, the map may be updated based on the collected measurements and the determined trajectory.

[0006] JP 2015 - 102 515 A discloses a detector for detecting a curve on which a runner is running even when the detection accuracy of position data by a GPS receiving equipment and the detection accuracy of geomagnetic quantity data by a geomagnetic sensor in a running condition detector are different. SUMMARY

[0007] According to the present invention, a positioning device, a positioning method, a mobile device and a computer program are provided as defined in the claims.

[0008] The foregoing paragraphs have been provided as a general introduction and are not intended to limit the scope of the following claims. The described embodiments, along with additional advantages, are best understood by reference to the following detailed description, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A more complete understanding of the disclosure and many of the attendant advantages thereof will be readily appreciated when the same becomes apparent by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which: Fig. 1 is a schematic diagram of a first embodiment of the mobile device including a position determining device according to the present disclosure, Fig. 2 is a schematic diagram of a second embodiment of the mobile device and the position determining device according to the present disclosure, Fig. 3 is a schematic diagram of a third embodiment of the mobile device including a position determining device according to the present disclosure, Fig. 4 illustrates a flowchart of an embodiment of a position determination method according to the present disclosure and Fig. 5 depicts various diagrams illustrating various steps of an embodiment of the position determination method according to the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0010] Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, Fig. 1 shows a schematic diagram of a first embodiment of the mobile device 1, such as a smartphone or other portable or handheld device. The mobile device 1 is particularly configured to determine its position, particularly indoors in certain premises where a conventional navigation system, such as the GPS system, does not work at all or does not work properly. Such a position determination can, for example, be useful or necessary for navigation in a shopping center, a factory, a parking garage, a hospital, an office building, a train station, an airport, etc., generally in larger buildings, to communicate to the user of the mobile device where they are and / or where they should go, and / or to communicate to other people (such as a caregiver in a hospital or retirement home) where the user of the mobile device is (e.g.a patient or an elderly person) is currently located.

[0011] The mobile device 1 includes a magnetic field sensor 10 (also called a magnetic position sensor or magnetometer) for detecting at least one magnetic field vector at the position of the mobile device 1. Such magnetic field sensors are commonly known and are used, for example, in Hall technologies or magnetoresistive technologies. Conventional smartphones include such a magnetic field sensor to create a miniature Hall-effect sensor that detects the Earth's magnetic field along three perpendicular axes X, Y, and Z. The Hall-effect sensor generates a voltage proportional to the strength and polarity of the magnetic field along the axis in which each sensor is aligned. Other technologies used for magnetic field sensors may include magnetoresistive devices, which change the measured resistance based on changes in the magnetic field.

[0012] The mobile device 1 further includes a position determining device 20 according to the present disclosure for determining the position of the mobile device 1 based on the at least one magnetic field vector detected by the magnetic field sensor 10. The position determining device 20 may be implemented in software, hardware, or a mixture of software and hardware. For example, a processor may be provided in the mobile device 1 that implements the functions of the position determining device 20. The processor may also be programmable, such that the functions are implemented by program code executed by the processor to perform the functions.

[0013] The position determining device 20 comprises a data input circuit 21 configured to receive at least one magnetic field vector detected by a magnetic field sensor 10, e.g., via a wired line, a bus line, or a wireless line, depending on the implementation of the mobile device 1, between the magnetic field sensor 10 and the data input 21, which may be a conventional data interface.

[0014] The position-determining device 20 further comprises a data processor circuit 22 that determines the magnetic field magnitude and an additional magnetic field parameter of the at least one obtained magnetic field vector. Conventionally, a magnetic field sensor 10 measures the magnetic field vector, e.g., the magnetic field components in the x, y, and z directions. These are converted into the magnetic field magnitude, i.e., the absolute value of the magnetic field intensity, and an additional magnetic field parameter used for position determination. This additional parameter is preferably the magnetic field inclination, which is the angle between the horizontal plane and the measured magnetic field vector. Other useful parameters may be the horizontal and / or vertical magnetic field component of the magnetic field vector.

[0015] The position-determining device 20 further comprises a comparison circuit 23 that compares the determined magnetic field magnitude with a predetermined magnetic field magnitude map of an area around the magnetic field sensor to obtain a first estimate of the sensor position, and compares the determined additional magnetic field parameter with a corresponding predetermined map of the additional parameter of an area around the magnetic field sensor to obtain a second estimate of the sensor position. These maps can either be stored in an (optional) memory circuit 30 (e.g., a semiconductor memory) or can be accessed spontaneously, e.g., they can be provided in the cloud, the Internet, or a server provided for wireless access by an optional access circuit 31 (e.g., a WiFi interface, a mobile communication interface, etc.) of the mobile device.For example, these maps can be available for free download or access, e.g., via Wi-Fi, upon entering the building (e.g., a shopping center), so that continuous navigation through the building can be guaranteed, for example, for the shopping center's customers and suppliers. Alternatively, these maps can be pre-stored on the mobile device 1.

[0016] The magnitude map indicates the magnetic field magnitude of the magnetic field vector at the premises, e.g., the shopping center, which represents the Earth's magnetic field distorted by the building and elements (walls, infrastructure, etc.) within the building. The additional parameter map indicates the additional magnetic field parameter (e.g., the magnetic field inclination) of the magnetic field vector at the premises.

[0017] These maps may be obtained in advance, e.g., by the owner or operator of the premises (e.g., the shopping mall), so that they can be obtained as an input by the mobile device via the data input circuit 21. Generally, such a magnetic field magnitude map and an additional parameter map are not available; only a horizontal magnetic field component map and a vertical magnetic field component map are available. Therefore, in this case, these available maps are obtained by the data input circuit 21, and the data processor circuit 22 determines the magnetic field magnitude map and / or the additional parameter map of the area around the magnetic field sensor 10 from the horizontal magnetic field component map and the vertical magnetic field component map.

[0018] Generally, the required maps are obtained by the positioning device 20 for an area around the magnetic field sensor 10. The area may depend on the size of the premises, the volume of maps, the desired application, the desired accuracy and / or reliability, etc. The area may be the entire premises, e.g., an entire building, such as an entire shopping center, but may also be a map of only a part of it, such as the map of a specific wing of the building or the floor where the mobile device is currently located (as known, e.g., from a previous positioning determination, e.g., based on GPS before the user enters the building, or based on the method disclosed herein, or based on a beacon signal that tells the mobile device where it is located).The area should be large enough to enable the desired position detection and optionally navigation with the desired accuracy and reliability.

[0019] The area may depend on a number of factors and can be adjusted dynamically. Such factors may include: the update rate of the positioning system (e.g., every second or every half second), the user's speed, the uncertainty derived from the positioning algorithm, local variation of the map (a homogeneous part requires a larger area, while a heterogeneous part allows for a smaller or medium-sized area), etc. The area may, for example, cover the entire floor or building if no initial position is given or the position estimate becomes very uncertain. In the case of position convergence, the area is typically on the order of a few meters (e.g., with a radius of 5 to 10 m).

[0020] These maps can thus be used to compare the measured magnetic field magnitude and the additional magnetic field parameter measured at a particular location with the map to obtain two separate estimates of the location where the measurements were obtained. These estimates can be lists of potential locations, optionally with a certain probability, or can be deviation maps. For example, in one embodiment, the comparison circuit 23 receives a first deviation distribution as a first estimate, the first deviation distribution indicating the deviation of the determined magnetic field magnitude from the magnetic field map, and a second deviation distribution as a second estimate, the second deviation distribution indicating the deviation of the determined additional magnetic field parameter from the additional parameter map.

[0021] The position determining device 20 further comprises a weighting determination circuit 24 that determines weighting information indicating the reliability of the first and / or second estimate of the sensor position and / or the relative weighting of the first estimate with respect to the second estimate. It has been found that the magnetic field magnitude is more reliable in certain situations and should be given greater weight, whereas the additional magnetic field parameter is more reliable in other situations and should be given greater weight. For example, if a user of the mobile device is walking, the magnetic field magnitude measurement is barely affected, whereas the additional magnetic field parameter may be greatly affected, in which case the first estimate should be given greater weight than the second estimate in the subsequent processing of the weighted estimates.

[0022] Finally, the position determination device 20 further comprises a position determination circuit 25 that weights the first and second estimates of the sensor position according to the determined weighting information and determines the sensor position from the weighted first and second estimates. For example, in one embodiment, the position determination circuit 25 is configured to determine a first position probability distribution from the first estimate and the weighting information, determine a second position probability distribution from the second estimate and the weighting information, and determine the sensor position by combining the first and second position probability distributions. There are different algorithms for obtaining the position estimate from such probability distributions (MMSE, ML, etc.).

[0023] In principle, it is better to have / use more dimensions for matching fingerprints, as this will lead to more unique results and fewer duplicates. This assumes that the fingerprint components are available and reliable. The magnetic field is a 3-dimensional vector (x, y, z), which theoretically provides a 3-dimensional magnetic field fingerprint. In general, the measurements depend on the orientation of the sensor. Using an accelerometer (which is typically also available in a smartphone), the magnetic x, y, z components can be resolved into a vertical component (direction of gravity) and a horizontal component. To additionally differentiate according to "world coordinates," information about "true north" would be required.This is typically not the case, so most implementations of the geomagnetic approach analyze a horizontal and vertical component or only the magnetic field magnitude.

[0024] It has been found that the transformation (x,y,z) -> (horizontal, vertical) based on the accelerometer (gravity) sensor is unreliable, especially when the sensor is in motion (e.g., a person walking with a smartphone), whereas the magnetic field magnitude does not suffer. Thus, the present disclosure proposes to form magnetic fingerprints of the magnetic field magnitude and another magnetic field parameter, in particular, their complementary magnetic field inclination. Furthermore, the estimates obtained from the two parameters are weighted according to their reliability (or availability as a "limiting case"). Since the magnetic field inclination is orthogonal to the magnetic field magnitude, its use is preferred.

[0025] At the Fig. In the embodiment shown in Figure 1, all elements of the mobile device 1 are integrated into a single device, which may be, for example, a handheld device, a portable device, a mobile phone, a smartphone, a portable phone, a camera, a watch, a vital sign monitor, a laptop, a tablet, or glasses. In another embodiment, as shown in Fig. 2, the mobile device 2 and the positioning device 40 may be arranged at different locations and not integrated into a single device.

[0026] For example, the mobile device 2 may be a device guided by the user, and it includes the magnetic field sensor 10, a wireless interface 11, and a user interface 12, but not the positioning device 40. The positioning device 40 may, for example, be implemented in a central computer system, a server, or a workstation located somewhere in the premises and provided by the owner or operator of the premises, or located somewhere in the cloud or on the Internet. The data measured by the magnetic field sensor 10 is thus transmitted through the wireless interface 11 (e.g., a WiFi transceiver or other communication circuitry, such as used for mobile communications) via a network 50 (e.g., WiFi network, communication network, ...) to the positioning device 40, which, in addition to the Fig. 1, may itself comprise a corresponding wireless interface 27 or receive the measured data from the central computer system that includes such a wireless interface. The determined position information is then transmitted back to the mobile device 2 via the wireless interface 11 so that it can be used by the mobile device 2 to indicate on the user interface 12 (e.g., a display) the current position and / or the route the user should take to a desired destination.

[0027] This embodiment thus provides the advantage that the mobile device does not need to be configured to perform all of the positioning device's processing, i.e., it can be configured much more simply with less hardware and software, and furthermore, it is not required to obtain and optionally store any maps as described above, which can also be performed by the positioning device 40. The mobile device 2 can thus be, for example, a fairly simple wrist-worn device or camera.

[0028] A schematic diagram of a third embodiment of the mobile device 3 including a position determining device 60 according to the present disclosure is shown in Fig. 3. In this embodiment, the mobile device 3 further includes a motion detector 13, e.g., an accelerometer, for obtaining motion information indicative of a movement of the mobile device 3. The motion information is used by the weighting determination circuit 24 to determine the weighting information based on the motion information. This motion information may be, for example, a movement of the user's body part that guides the mobile device 3 or the user's step pattern.

[0029] In one embodiment, if it is detected that a user is standing, preferably both magnetic field parameters are used (the magnitude and the additional parameter), e.g., both are weighted equally, since both should be reliable and more parameters generally provide better (more unambiguous) agreement results. If it is detected that a user is walking (quickly), only or mainly the robust (motion-independent) magnetic field magnitude is used for position determination, i.e., the first estimate is weighted with a larger weight than the second estimate, which may even be weighted with zero. If no motion detector (or gravimeter) is available (or their signals cannot be combined), in one embodiment only or mainly the magnetic field magnitude is used.

[0030] The position determination circuit 60 may further include a filter 26 for low-pass filtering the obtained at least one magnetic field vector, wherein at least two sequentially sampled magnetic field vectors are preferably used to apply the filter 26. In this case, the data processor circuit 22 determines the magnetic field magnitude and the additional magnetic field parameter from the at least one filtered magnetic field vector.

[0031] Furthermore, in this embodiment, local variation information of the magnetic field parameters (magnetic field magnitude, additional magnetic field parameter) can be used in the weighting process. The local variation information can be derived from the map data and thus can be previously calculated and stored together with the magnetic field data in the map for local sensor areas, e.g., in an area having a radius in a range between 1 m and 20 m, particularly in a range between 2 m and 10 m (e.g., 5 m radius). Therefore, the local variation can be stored in the storage circuit 30 and obtained by the weighting determination circuit 24 for additional processing.In another embodiment, the weighting determination circuit 24 may be configured to determine the local variation in the local sensor area of ​​the magnetic field magnitude in the magnetic field magnitude map and / or the additional magnetic field parameter in the additional parameter map from the magnetic field magnitude map and / or the additional parameter map (e.g., spontaneously).

[0032] In one embodiment, the weighting determination circuit 24 is further configured to determine the weighting information such that the weighting of the second estimate is increased the fewer variations in the magnetic field size, the less movement and / or the fewer steps are indicated in the local sensor area, ie in this case the estimate from the additional parameter is assumed to be more reliable.

[0033] In another embodiment, the weighting determination circuit 24 is further configured to determine the weighting information such that the weighting of the first estimate is decreased the less variation in the magnetic field magnitude is indicated in the local sensor area, and / or the weighting of the second estimate is increased the more variation in the additional magnetic field parameter is indicated in the local sensor area. Thus, if the magnetic field magnitude is almost constant in the vicinity of the estimated (or true) position, whereas the additional parameter (e.g., inclination) exhibits larger variations in the same area, the same or higher weighting could be applied to the additional parameter, even if it is less reliable compared to the magnetic field magnitude.

[0034] In another embodiment, the comparison circuit 23 is further configured to use, as an initial sensor position for determining the area around the magnetic field sensor, an estimate determined based on the last known position of the magnetic field sensor (e.g., from the most recent GPS signal, for example, before the user enters the building), and to reduce the size of the area around the magnetic field sensor in subsequent comparison steps to reduce the volume and time of calculations required for the position determination.

[0035] In another embodiment, the data input 21 is further configured to receive motion information indicating a movement of the magnetic field sensor, and the data processor 22 is further configured to determine the magnetic field inclination of the at least one obtained magnetic field vector as an additional magnetic field parameter and to correct the determined magnetic field inclination for a rotation of the magnetic field sensor based on the obtained motion information. This further improves the accuracy and reliability of the position determination.

[0036] In yet another embodiment, there may be some sort of rescue or reset procedure, e.g., if the position cannot be determined by the proposed method, for example, because the user suddenly changes direction and / or moves very quickly to leave the detection range, due to some new installation present in the premises that has not yet been considered in the respective maps or that prevents reliable positioning, etc. Such a procedure may be initiated, e.g., if the probability of the determined position is quite low compared to previous probabilities of determined positions. In this case, the local sensor range may be increased, or the positioning may be restarted entirely.

[0037] In general, the disclosed devices and method dynamically integrate the advantages of two fingerprint systems depending on the reliability and amount of local variation of the available information. The more reliable a fingerprint component is and the more local variation it exhibits, the higher it is generally weighted.

[0038] A flowchart of an embodiment of the proposed positioning method is shown in Fig. 4. Various steps of a practical implementation of the method are described in more detail with reference to various diagrams shown in Fig. 5 are explained.

[0039] A first step S10 comprises obtaining at least one magnetic field vector detected by a magnetic field sensor. A second step S12 comprises determining the magnetic field magnitude (e.g., indicated as m1) and an additional magnetic field parameter (e.g., indicated as m2) of the at least one obtained magnetic field vector (e.g., indicated as m→=(m1m2) specified).

[0040] A third step S14 comprises comparing the determined magnetic field magnitude m1 with a predetermined magnetic field magnitude map M1 (as shown in Fig. 5A, which represents the magnetic field strength in µT in a local sensor area) of an area around the magnetic field sensor to obtain a first estimate of the sensor position. The first estimate may thus be a first deviation distribution D1 (also called a first deviation map, as in Fig. 5C, which represents the deviation error in absolute numbers in the local sensor area), where the first deviation distribution D1 indicates the deviation of the determined magnetic field magnitude m1 from the magnitude map M1.

[0041] A fourth step S16 comprises comparing the determined additional magnetic field parameter m2 with a corresponding predetermined map M2 of the additional parameter (as in Fig. 5B) of an area around the magnetic field sensor to obtain a second estimate of the sensor position. The second estimate may thus be a second deviation distribution D2 (also called a second deviation map), as shown in Fig. 5D, wherein the second deviation distribution D2 indicates the deviation of the determined additional magnetic field parameter m2 from the additional parameter map M2.

[0042] A fifth step S18 comprises determining weighting information indicating the reliability of the first and / or second estimate of the sensor position and / or the relative weighting of the first estimate with respect to the second estimate. The weightings can be expressed, for example, as parameters σ1 and σ2.

[0043] A sixth step S20 comprises weighting the first and second sensor position estimates according to the determined weighting information. Weighting can be performed by separately applying (for each estimate) a maximum likelihood estimate having the following form: P(m / (x,y))=12πσ2e−12σ2[(m−M(x,y))2] where m = m1 or m2, M = M1 or M2 respectively . σ = σ1 or σ2, which leads to two probability distributions (also called position probability distribution maps) P1 and P2, as shown in the Fig. 5E and Fig. 5F (which represents the probability of different positions in the local sensor area).

[0044] A seventh step S22 comprises determining the sensor position from the weighted first and second estimates. This can be done by a point-by-point multiplication of the probability distributions P1 and P2, resulting in a final probability distribution P3, as shown in Fig. 5G. Such a multiplication is particularly useful in the case where the probabilities of both components m1 and m2 are statistically independent. The weighting can be implemented by using different weighting factors σ1 and σ2 for both components (standard deviation of both Gaussian distribution functions).

[0045] In summary, one object of the present disclosure can be seen as providing a positioning device and a corresponding positioning method for determining the position of the device, particularly indoors, with greater reliability and accuracy. A further object is to provide a corresponding mobile device and a non-transitory computer-readable recording medium for implementing the positioning method.

[0046] According to one aspect, a position determining device is provided, comprising: - a data input circuit configured to receive at least one magnetic field vector detected by a magnetic field sensor, - a data processor circuit configured to determine the magnetic field magnitude and an additional magnetic field parameter of the at least one obtained magnetic field vector, - a comparison circuit configured to compare the determined magnetic field magnitude with a predetermined magnetic field magnitude map of an area around the magnetic field sensor to obtain a first estimate of the sensor position, and to compare the determined additional magnetic field parameter with a corresponding predetermined map of the additional parameter of an area around the magnetic field sensor to obtain a second estimate of the sensor position, - a weighting determination circuit configured to determine weighting information indicating the reliability of the first and / or second estimate of the sensor position and / or the relative weighting of the first estimate with respect to the second estimate, and - a position determination circuit configured to weight the first and second estimates of the sensor position according to the determined weighting information and to determine the sensor position from the weighted first and second estimates.

[0047] According to a further aspect, a positioning method is provided, comprising: - Obtaining at least one magnetic field vector detected by a magnetic field sensor, - determining the magnetic field magnitude and an additional magnetic field parameter of the at least one obtained magnetic field vector, - comparing the determined magnetic field size with a predetermined magnetic field size map of an area around the magnetic field sensor to obtain a first estimate of the sensor position, - comparing the determined additional magnetic field parameter with a corresponding predetermined map of the additional parameter of an area around the magnetic field sensor to obtain a second estimate of the sensor position, - determining weighting information indicating the reliability of the first and / or second estimate of the sensor position and / or the relative weighting of the first estimate with respect to the second estimate, - weighting the first and second estimates of the sensor position according to the determined weighting information and - Determining the sensor position from the weighted first and second estimates.

[0048] According to still further aspects, a computer program comprising program means for causing a computer to perform the steps of the presently disclosed method when the computer program is executed on a computer, and a non-transitory computer-readable recording medium storing therein a computer program product that, when executed by a processor, causes the presently disclosed method to be performed are provided.

[0049] Embodiments are defined in the dependent claims. It is understood that the disclosed method, the disclosed computer program, and the disclosed computer-readable recording medium have similar and / or identical preferred embodiments as the claimed device and as defined in the dependent claims.

[0050] One aspect of the disclosure is to use a magnetic field magnitude and a second magnetic field parameter (and optionally one or more additional magnetic field parameters) of the magnetic field vector detected by the magnetic field sensor, as currently available in various mobile devices, such as smartphones, instead of vertical and horizontal components of the magnetic field vector. From the used parameters, the position of the magnetic field sensor (i.e., the mobile device including the magnetic field sensor) is estimated. The estimates are then dynamically weighted based on dynamically obtained weighting information when combined to ultimately determine the position of the magnetic field sensor. This increases the reliability and accuracy of the determined position.

[0051] Thus, the foregoing discussion merely discloses and describes embodiments of the present disclosure. As will be understood by those skilled in the art, the present disclosure may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present disclosure is intended to be illustrative, but not to limit the scope of the disclosure, as well as other claims. The disclosure, including any readily observable variations of the present teachings, in part defines the scope of the foregoing claim terminology such that no inventive subject matter is directed to the public.

[0052] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single element or other unit may perform the functions of several of the things recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of those measures cannot be used to advantage.

[0053] To the extent that embodiments of the disclosure have been described, at least in part, as being implemented in a software-controlled processing device, it should be understood that a non-transitory machine-readable medium carrying such software, such as an optical disk, a magnetic disk, a semiconductor memory, or the like, is also considered to represent an embodiment of the present disclosure. Furthermore, such software may be distributed in other forms, such as over the Internet or other wired or wireless telecommunications systems.

[0054] The elements of the disclosed devices, apparatus, and systems may be implemented by corresponding hardware and / or software elements, such as dedicated circuits or circuits (sometimes referred to as a unit or assembly). A circuit or circuit is a structural arrangement of electronic components, including conventional circuit elements, integrated circuits, including application-specific integrated circuits, standard integrated circuits, application-specific off-the-shelf products, and field-programmable gate arrays. Furthermore, a circuit includes central processing units, graphics processing units, and microprocessors programmed or configured according to software code. A circuit does not include pure software, although a circuit includes the hardware described above that executes software.

[0055] The following is a list of further embodiments of the disclosed subject matter: 1. A positioning device comprising: - a data input circuit configured to receive at least one magnetic field vector detected by a magnetic field sensor, - a data processor circuit configured to determine the magnetic field magnitude and an additional magnetic field parameter of the at least one obtained magnetic field vector, - a comparison circuit configured to compare the determined magnetic field magnitude with a predetermined magnetic field magnitude map of an area around the magnetic field sensor to obtain a first estimate of the sensor position, and to compare the determined additional magnetic field parameter with a corresponding predetermined map of the additional parameter of an area around the magnetic field sensor to obtain a second estimate of the sensor position, - a weighting determination circuit configured to determine weighting information indicating the reliability of the first and / or second estimate of the sensor position and / or the relative weighting of the first estimate with respect to the second estimate, and - a position determination circuit configured to weight the first and second estimates of the sensor position according to the determined weighting information and to determine the sensor position from the weighted first and second estimates. 2. The position determining device as defined in embodiment 1, wherein the data processor circuit is further configured to determine the magnetic field inclination, the vertical magnetic field component, or the horizontal magnetic field component of the at least one obtained magnetic field vector as an additional magnetic field parameter. 3. The position determining device as defined in embodiment 1 or 2, wherein the weighting determination circuit is further configured to determine the weighting information based on the variation of the additional magnetic field parameter, the direction of gravity, the movement, and / or the step pattern. 4. The position determining device as claimed in embodiment 3, wherein the weighting determination circuit is further configured to determine the weighting information such that the weighting of the second estimate is increased the fewer variations in the magnetic field size, the less movement and / or the fewer steps are indicated in the local sensor area. 5. The position determining device as defined in any preceding embodiment, wherein the weighting determination circuit is further configured to determine the weighting information based on the local variation in a local sensor area of ​​the magnetic field magnitude in the magnetic field magnitude map and / or the additional magnetic field parameter in the additional parameter map. 6. The position determining device as claimed in embodiment 5, wherein the weighting determination circuit is further configured to determine the weighting information such that the weighting of the first estimate is decreased the less variation of the magnetic field magnitude is indicated in the local sensor area, and / or that the weighting of the second estimate is increased the more variations of the additional magnetic field parameter are indicated in the local sensor area. 7. The position determining device as claimed in embodiment 5, wherein the weighting determination circuit is further configured to determine the local variation in the local sensor area of ​​the magnetic field magnitude in the magnetic field magnitude map and / or the additional magnetic field parameter in the additional parameter map from the magnetic field magnitude map and / or the additional parameter map. 8. The position determining device as claimed in embodiment 5, wherein the weight determination circuit is further configured to receive the local variation as a predetermined input. 9. The position determining device as defined in any preceding embodiment, wherein the data input circuit is further configured to obtain a map of the horizontal magnetic field component and a map of the vertical magnetic field component of the region around the magnetic field sensor, and the data processor is further configured to determine the magnetic field magnitude map and / or the additional parameter map of the region around the magnetic field sensor from the obtained map of the horizontal magnetic field component and the map of the vertical magnetic field component. 10. The position determining device as defined in embodiment 1, wherein the data input circuit is further configured to receive the magnetic field magnitude map and / or the additional parameter map as a predetermined input. 11. The position determining device as defined in any preceding embodiment, wherein the weighting determination circuit is further configured to use an area having a radius in a range between 1 m and 20 m, in particular in a range between 2 m and 10 m, as a local sensor area. 12. The position determining device as defined in any preceding embodiment, further comprising a filter configured to low-pass filter the obtained at least one magnetic field vector, wherein the data processor is configured to determine the magnetic field magnitude and the additional magnetic field parameter from the at least one filtered magnetic field vector. 13. The position determining device as defined in any preceding embodiment, wherein the comparison circuit is further configured to use an estimate determined based on the last known position of the magnetic field sensor as an initial sensor position for determining the area around the magnetic field sensor and to decrease the size of the area around the magnetic field sensor in subsequent comparison steps. 14. The position determining device as defined in any preceding embodiment, wherein the data input circuit is further configured to receive motion information and / or orientation information indicating a movement and / or orientation of the magnetic field sensor, and wherein the data processor is further configured to determine the magnetic field inclination of the at least one obtained magnetic field vector as an additional magnetic field parameter and to correct the determined magnetic field inclination for a rotation of the magnetic field sensor based on the obtained motion information. 15. The position determining device as defined in any preceding embodiment, wherein the position determination circuit is configured to determine a first position probability distribution from the first estimate and the weighting information, to determine a second position probability distribution from the second estimate and the weighting information, and to determine the sensor position by combining the first and the second position probability distribution, in particular by a point-by-point multiplication. 16. The position determining device as defined in embodiment 15, wherein the comparison circuit is configured to obtain a first deviation distribution as a first estimate, the first deviation distribution indicating the deviation of the determined magnetic field quantity from the magnetic field map, and to obtain a second deviation distribution as a second estimate, the second deviation distribution indicating the deviation of the determined additional magnetic field parameter from the additional parameter map. 17. A positioning method comprising: - Obtaining at least one magnetic field vector detected by a magnetic field sensor, - determining the magnetic field magnitude and an additional magnetic field parameter of the at least one obtained magnetic field vector, - comparing the determined magnetic field size with a predetermined magnetic field size map of an area around the magnetic field sensor to obtain a first estimate of the sensor position, - comparing the determined additional magnetic field parameter with a corresponding predetermined map of the additional parameter of an area around the magnetic field sensor to obtain a second estimate of the sensor position, - determining weighting information indicating the reliability of the first and / or second estimate of the sensor position and / or the relative weighting of the first estimate with respect to the second estimate, - weighting the first and second estimates of the sensor position according to the determined weighting information and - Determining the sensor position from the weighted first and second estimates. 18. A mobile facility comprising: - a magnetic field sensor for detecting at least one magnetic field vector at the position of the mobile device, - a position determining device as defined in embodiment 1, for determining the position of the mobile device based on the at least one magnetic field vector detected by the magnetic field sensor. 19. The mobile device as defined in Embodiment 18, further comprising a motion detector for obtaining motion information indicative of a movement of the mobile device, wherein the one position determining device is configured as claimed in embodiment 3 or 16. 20. The mobile device as defined in embodiment 18 or 19, wherein the mobile device is a handheld device or a portable device or a mobile phone or a smartphone or a portable phone or a camera or a watch or a vital signs monitor or a laptop or a tablet or glasses. 21. A non-transitory computer-readable recording medium having stored therein a computer program product which, when executed by a processor, causes the method of claim 17 to be performed. 22. A computer program comprising program code means for causing a computer to perform the steps of the method of embodiment 17 when the computer program is executed on a computer.

Claims

[1] Positioning device comprising: - a data input circuit (21) configured to receive at least one magnetic field vector detected by a magnetic field sensor (10), - a data processor circuit (22) configured to determine the magnetic field magnitude and an additional magnetic field parameter of the at least one obtained magnetic field vector, - a comparison circuit (23) configured to compare the determined magnetic field magnitude with a predetermined magnetic field magnitude map of an area around the magnetic field sensor to obtain a first estimate of the sensor position, and to compare the determined additional magnetic field parameter with a corresponding predetermined map of the additional parameter of an area around the magnetic field sensor to obtain a second estimate of the sensor position, - a weighting determination circuit (24) configured to determine weighting information indicating the reliability of the first and / or the second estimate of the sensor position and / or the relative weighting of the first estimate with respect to the second estimate, wherein the weighting information is determined based on the local variation in a local sensor area of the magnetic field magnitude in the magnetic field magnitude map and / or the additional magnetic field parameter in the additional parameter map, and - a position determination circuit (25) configured to weight the first and second estimates of the sensor position according to the determined weighting information and to determine the sensor position from the weighted first and second estimates. [2] Position determining device according to claim 1, wherein the data processor circuit (22) is further configured to determine the magnetic field inclination, the vertical magnetic field component or the horizontal magnetic field component of the at least one obtained magnetic field vector as an additional magnetic field parameter. [3] The position determining device according to claim 1, wherein the weighting determining circuit (24) is further configured to determine the weighting information based on the variation of the additional magnetic field parameter, the direction of gravity, the movement and / or the step pattern. [4] Position determining device according to claim 3, wherein the weighting determination circuit (24) is further configured to determine the weighting information such that the weighting of the second estimate is increased the fewer variations in the magnetic field size, the less movement and / or the fewer steps are indicated in the local sensor area. [5] Position determining device according to claim 1, wherein the weighting determination circuit (24) is further configured to determine the weighting information such that the weighting of the first estimate is reduced the less variation of the magnetic field magnitude is indicated in the local sensor area, and / or that the weighting of the second estimate is increased the more variation of the additional magnetic field parameter is indicated in the local sensor area. [6] Position determining device according to claim 1, wherein the weight determination circuit (24) is further configured to determine the local variation in the local sensor area of the magnetic field magnitude in the magnetic field magnitude map and / or the additional magnetic field parameter in the additional parameter map from the magnetic field magnitude map and / or the additional parameter map. [7] The position determining device according to claim 1, wherein the weight determining circuit (24) is further configured to receive the local variation as a predetermined input. [8] The position determining device according to claim 1, wherein the data input circuit (21) is further configured to obtain a horizontal magnetic field component map and a vertical magnetic field component map of the area around the magnetic field sensor, and the data processor circuit (22) is further configured to determine the magnetic field magnitude map and / or the additional parameter map of the area around the magnetic field sensor from the obtained horizontal magnetic field component map and the vertical magnetic field component map. [9] The position determining device according to claim 1, wherein the data input circuit (21) is further configured to receive the magnetic field magnitude map and / or the additional parameter map as a predetermined input. [10] Position determining device according to claim 1, wherein the weighting determination circuit (24) is further configured to use an area having a radius in a range between 1 m and 20 m, in particular in a range between 5 m and 10 m, as a local sensor area. [11] The position determining device according to claim 1, wherein the position determining circuit (25) is configured to determine a first position probability distribution from the first estimate and the weighting information, to determine a second position probability distribution from the second estimate and the weighting information, and to determine the sensor position by combining the first and second position probability distributions. [12] Position determining device according to claim 1, wherein the comparison circuit (23) is configured to obtain a first deviation distribution as a first estimate, the first deviation distribution indicating the deviation of the determined magnetic field quantity from the magnetic field map, and to obtain a second deviation distribution as a second estimate, the second deviation distribution indicating the deviation of the determined additional magnetic field parameter from the additional parameter map. [13] The position determining device of claim 1, wherein the comparison circuit (23) is further configured to use an estimate determined based on the last known position of the magnetic field sensor as an initial sensor position for determining the area around the magnetic field sensor and to reduce the size of the area around the magnetic field sensor in subsequent comparison steps. [14] Position determining device according to claim 1, wherein the data input circuit (21) is further configured to receive movement information and / or orientation information indicating a movement and / or orientation of the magnetic field sensor, and wherein the data processor circuit (22) is further configured to determine the magnetic field inclination of the at least one obtained magnetic field vector as an additional magnetic field parameter and to correct the determined magnetic field inclination for a rotation of the magnetic field sensor based on the obtained movement information. [15] Positioning method comprising: - Obtaining at least one magnetic field vector detected by a magnetic field sensor (10), - determining the magnetic field magnitude and an additional magnetic field parameter of the at least one obtained magnetic field vector, - comparing the determined magnetic field size with a predetermined magnetic field size map of an area around the magnetic field sensor to obtain a first estimate of the sensor position, - comparing the determined additional magnetic field parameter with a corresponding predetermined map of the additional parameter of an area around the magnetic field sensor to obtain a second estimate of the sensor position, - Determining weighting information indicating the reliability of the first and / or the second estimate of the sensor position and / or the relative weighting of the first estimate with respect to the second estimate, wherein the weighting information is determined based on the local variation in a local sensor area of the magnetic field magnitude in the magnetic field magnitude map and / or the additional magnetic field parameter in the additional parameter map, - weighting the first and second estimates of the sensor position according to the determined weighting information and - Determining the sensor position from the weighted first and second estimates. [16] Mobile facility comprising: - a magnetic field sensor (10) for detecting at least one magnetic field vector at the position of the mobile device, - a position determining device (20, 40, 60) as claimed in claim 1, for determining the position of the mobile device based on the at least one magnetic field vector detected by the magnetic field sensor. [17] Mobile device according to claim 16, further comprising a motion detector (13) for obtaining motion information indicative of a movement of the mobile device, wherein said one position determining device (60) is configured as claimed in claim 3 or 15. [18] Mobile device according to claim 16, wherein the mobile device is a handheld device or a portable device or a mobile phone or a smartphone or a portable phone or a camera or a watch or a vital signs monitor or a laptop or a tablet or glasses. [19] A computer program comprising program code means for causing a computer to perform the steps of the method of claim 15 when the computer program is executed on a computer.

Images