Patent Grant
9078104
The invention relates generally to indoor positioning systems. More particularly, the invention relates to utilization of the magnetic field based navigation, such as in detecting a change in the operational environment and initialization of a positioning device for location discovery and/or tracking.
It may be of importance to locate or track a user when the user is inside a building. However, a well-known outdoor positioning system to employing a global positioning system (GPS) or any other satellite based system may not work inside a building due to lack of reliable reception of satellite coverage. Therefore, a positioning technique utilizing Earth's magnetic fields (EMF) indoors has been developed as one possible option for indoor location discovery. This type of location discovery applies, for example, a magnetic field strength measured by a positioning device. However, problems are related to this type of location estimation, especially in how to detect a change in the operational environment and how to initialize the positioning device for applying the EMF based positioning technique, for example.
According to an aspect of the invention, there is provided a location estimation and/or tracking system as specified in claim 1.
According to an aspect of the invention, there is provided a cellular phone for use in the location estimation and/or tracking system as specified in claim 12.
According to an aspect of the invention, there is provided a database server for use in the location estimation and/or tracking system as specified in claim 13.
Embodiments of the invention are defined in the dependent claims.
In the following, the invention will be described in greater detail with reference to the embodiments and the accompanying drawings, in which
The following embodiments are exemplary. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.
In order to enable positioning, a radio frequency (RF) and/or GPS based location discovery and/or tracking is known. The GPS location discovery may not, however, be suitable for indoors due to lack of satellite reception coverage. Also the RF based location discovery and location tracking may only be possible by determining the indoor base station to which the user device is connected to, a round trip time of the RE signal, or the power of the received RF signal, for example. This type of location tracking may suffer from a lack of accuracy, for example, when the user gets located by two different RF base stations. Also, the coverage area of one base station may be wide resulting in poor accuracy. Some other known positioning measures, which may be applicable indoors, include machine vision, motion sensor and distance measuring, for example. However, each of these requires expensive measuring devices and equipment mounted throughout the building. As a further option, the utilization of Earth's magnetic field (EMF) may be applied.
The material used for constructing the building may affect the EMF measurable in the building and also the EMF surrounding the building. For example, steel, reinforced concrete, and electrical systems may affect the EMF. The EMF may vary significantly between different locations in the building and may therefore enable accurate location discovery and tracking inside the building based on the EMF local deviations inside the building. On the other hand, the equipment placed in a certain location in the building may not affect the EMF significantly compared to the effect caused by the building material, etc. Therefore, even if the layout and amount of equipment and/or furniture, etc., change, the measured EMF may not change significantly.
An example of a building 100 with 5 rooms, a corridor and a hall is depicted in
As said, the magnetometer carried by a person traversing the path 102 in
In location tracking of the user or any target object moving in the building 100, the EMF vector measured by the positioning device carried by the user may be compared to existing information, wherein the information may comprise EMF vector strength and direction in several locations within the building 100. The information may depict an indoor Earth's magnetic held map. The positioning device of the user may comprise at least part of the EMF map, the positioning device may access the EMF map stored somewhere else in a network accessible by the positioning device, or the positioning device may forward the measured EMF vector data to a database entity or server which comprises or has access to the EMF map and thus is capable to locate the user in the floor plan of the building. Preferably but not necessarily, the EMF map covers most or all of the building so that the user may be reliably located without “black spots”.
However, it may be cumbersome and time consuming for the user to detect a change in the operational environment, such as a change between indoors (e.g. the building 100) and outdoors, and perform required actions based on that. At least partly for this reason, a solution is provided in which it is, with reference to
Further, it is proposed to acquire in step 302 a first sequence of magnetic field measurement carried out by the PD 400 upon detecting that the PD 400 is within the predetermined control area 402A, 402B. Let us assume that the PD 400 traverses a path 406A in
Further, it is proposed to determine in step 304 that an operational environment of the positioning device 400 has changed between an indoor environment and an outdoor environment when at least one predetermined criterion with respect to at least part of the first sequence is met. The at least one predetermined criterion is detailed later but for now it may be said that the first sequence may be monitored alone or in comparison to another sequence. The first sequence may be monitored continuously in order to detect the change in the operational environment or it may be monitored according to predetermined intervals, or it may be monitored once the EMF 208 measurements to be comprised in the first sequence are finished, which may take place once a predetermined time limit expires, for example. The change of operational environment may be detected when the PD 400 has moved from outdoor to indoors at point 410 of
In an embodiment, when it is detected in step 304 that the operational environment of the positioning device 400 has changed at point 410 or at point 411, an actuation of a predetermined software function in or with respect to the positioning device 400 may be automatically caused in step 306. The database entity 500 may cause the activation by sending a command to the PD 400, or the PD 400 may cause the activation itself. Such a predetermined software function may comprise for example a navigation system. When the operational environment changes from outdoors to indoors or from indoors to outdoors, it may be advantageous to change into using a corresponding navigation system. Therefore, an activation of either an application employing an indoor magnetic field based positioning system or an application employing an outdoor positioning system may be caused in the positioning device 400 when the operational environment of the positioning device 400 has changed. The application employing the indoor magnetic field may use an indoor magnetic field map representing at least one of magnitude and direction of Earth's magnetic field 208 affected by the local structures of the budding 100 at a given location inside the building 100. This way the embodiment provides a seamless navigation even if the user moves from outdoors to indoors, or vice versa. By knowing or accessing the existing EMF map data, the PD 400 may be able to determine its location in the building 100 by comparing the measured EMF vector to the EMF map.
In another embodiment, such a predetermined software function may comprise for example a reference to a social network. For example, such a reference may be a check-in to the Facebook Places, Foursquare social network, a status update to the Facebook, or to the Twitter, wherein the status update refers to the location of the user associated with the PD 400, for example. In other words, when it is detected that the operational environment has changed, for example, from outdoors to indoors, the PD 400 may automatically check-in to the Foursquare. This may be advantageous for the user so that the user need not himself perform the reference to the social network. Further, as will be described later, the entry of the building among a plurality of entries may optionally be detected. This may further aid in specifying the check-in location of the user to the building so that the check-in location may correspond to the specific entry of the building.
Let us now take a look at how it is determined that the operational environment has changed.
In an embodiment, the at least one criterion is a predetermined similarity between the first sequence 420 and a second magnetic field sequence 422, as shown in
As said, the second sequence 422 may be obtained from prior measurements carried out in a controlled manner. The controlled manner may refer to the three-dimensional orientation of a measuring device, as will be described later. In an embodiment, as shown in
In an embodiment, as shown in FIGS. in 6A and 6B, it may be assumed that the at least one measuring device 600 has measured the path 606A, 606B, each path 606A, 606B comprising an entry 412A, 412B to the building. The acquired second sequences 422A and 422B, respectively, may be seen in
A further advantage may be that the positioning device 400 may be initialized with the indoor location estimate corresponding to the identified location, i.e. the entry 412A or 412B. To enable the correct initial location estimation significantly enhances the efficiency of indoor positioning system, such as the EMF based navigation system. For example, when the indoor positioning system applies a multi-hypothesis location estimation, the number of different hypothesis may in the beginning include over 1000 location hypothesis for the positioning device 400. Therefore, it may be understood that it may take a lot of time to converge to the correct hypothesis. By enabling the initial location estimate, the efficiency of the location discovery is increased as the number of location hypothesis may be reduced closer to the identified entry 412A or 412B. Thus, the time of convergence to the correct location may be reduced.
In an embodiment, as shown in
However, in an embodiment, the X-axis represents distance moved by the positioning device 400. The motion estimate needed for the distance representation may be acquired from at least one motion sensor coupled to the positioning device 400. The motion sensor may be comprised in an inertial measurement unit (IMU). The motion sensor may comprise for example at least one acceleration sensor or an odometer. The motion sensor may detect the movement of the positioning device and provide as output an estimate of the movement. The estimate may comprise at least the amount of movement. i.e. for example, how many meters the positioning device 400 has moved and/or how many steps the person carrying the PD 400 has taken. In addition, the direction of the movement may be determined by the motion sensor. The distance information obtained may be used to pair the measured EMF value to a distance. Thus, it is possible to represent the first magnetic field sequence 420 as a function of distance with respect to the motion of the positioning device 400. This may be beneficial for the comparison of two sequences 420 and 422. For example, the second sequence 422 may have been measured so that the measuring device 600 has been moving along the path. Now the first sequence 420 may also be directly represented in the distance domain. Thus, even if the person with the positioning device 400 providing the first sequence 420 has stopped at some point along the path, the first sequence 420 in the distance domain may still be directly comparable to the second sequence 422.
As said, the measuring device 600 measures the EMF vectors for the paths 606A, 606B in a controlled manner in order to provide second sequences 422A, 422B. The controlled manner may refer to the three-dimensional orientation of a measuring device. In other words, the measuring device 600 may be kept in a correct three-dimension orientation so that the frame of reference of the measuring device 600 corresponds to the frame of reference of the building 100, for example, as shown in
The three-dimensional orientation of the measuring device 400 may be defined by at least one of the following: a rotation with respect to a first horizontal axis (such as X-axis or Y-axis), a rotation with respect to a second horizontal axis (such as Y-axis or X-axis, respectively), and a rotation with respect to a vertical axis Z. Let us consider this in more detail by referring to
Although the rotation about the X and Y axis may in general be correctable because the global reference (the gravitational force G) is present, the rotation about the Z-axis as shown in
Let us assume that the positioning device 400 measures EMF vectors at any given point inside the building 100. Let us also assume that there exists an EMF map for the building 100, or at least for a part of the building 100, such as for the entries 412A, 412B. The EMF map may indicate EMF vector magnitude and/or three-dimensional direction for a given location in the building 100 or in a part of the building 100. As said, incorrect orientation of the positioning device 400 may lead to erroneous results or to a situation where only the magnitude of the EMF vector can be utilized but not the direction of the EMF vector in addition to the magnitude of the EMF vector. Therefore it is beneficial to adjust the measured magnetic field vector from the frame of reference of the positioning device 400 to the frame of reference of the floor plan the building 100. This may be done at least partly on the basis of the knowledge of the direction of the true magnetic field vector F, as referred in
For example, when there are two position hypotheses, the three-dimensional orientation adjustment at the correct location hypothesis performs better than at the false location hypothesis. This is because, when correcting the rotation based on Earth's gravitation G, the inclination of the measured EMF vector should approach the true EMF vector inclination F. If this is not the case, the position hypothesis may be determined as not correct or the probability of the reliability of the position hypothesis may be given a low value. This is because at a false position hypothesis, a wrong EMF vector direction F may be used. On the contrary, the orientation adjustment at the correct position hypothesis based on G, makes the measured inclination and true inclination F to be closer to each other. Then, the three-dimensional orientation correction based on F may be conducted, i.e. the three-dimensional orientation of the positioning device 400 with respect to the rotation about the Z-axis may be corrected at least partly based on F. The correction may be performed by the PD 400 or the database entity 500. Such three-dimensional orientation correction may be conducted even off-line if the positioning device 400 is equipped with the EMF map data. This way the three-dimensional orientation of the positioning device 400 may be adjusted properly and correct values of EMF measurement vector may be obtained.
However, in case the rotation about the z-axis cannot be corrected, which may be due to the lack of EMF map data (i.e. a global reference) for the location or location hypothesis of the PD 400, it may still be advantageous to determine the magnitude of the XY-plane projection and the magnitude of the Z-component. As said, the rotations about the XY-plane may be corrected using the global reference G. Namely, the norm of the XY-plane projection ∥m∥xy, of the EMF vector m=(x,y,z) may be determined as ∥m∥xy=sqrt(x2+y2) even without adjusting the rotation about the Z-axis. As a result, the feature vector (z, ∥m∥xy) may be computed from the tilt compensated magnetic field observation, which feature vector is invariant to the rotation about the Z-axis. These two features enable for more EMF vector information than the magnitude alone, because the magnitude may be represented separately for the Z-axis component and for the XY-plane projection.
This may additionally allow for representing the first sequence 420 as a function of distance which may be beneficial, as indicated before. In this case, the representation as a function of distance may be obtained through the location estimation (e.g. by using a multi-hypothesis location estimation) even without odometers or alike being comprised in the positioning device 400. The orientation adjustment may allow efficient location estimation based on direction of the EMF 208, in addition to or instead of the magnitude of the EMF 208. In an embodiment, the detection of operational environment change for the positioning device, and the location estimation is conducted separately for each entry of the building. In other words, the acquired measured EMF data is compared against the EMF data provided by the map for each entry location. As a result, each entry may be associated with a location estimate of the positioning device 400 as a function of time. The location estimate may represent the distance moved by the positioning device 400. As the location estimate is known for each entry as a function of time, each point of time may be associated with a distance moved and with a measured EMF vector (first sequence 420). Thus, it may be possible to generate the first sequence 420 as a function of distance. At the correct entry location, the localization result may be statistically more consistent, and the similarity between the mapped EMF vector sequence 422A, 422B and the first sequence 420 may be higher.
In an embodiment, the three-dimensional orientation correction at least partly based on the true magnetic field vector direction F is performed for determining probabilities for position hypotheses applied by multi-hypothesis location estimation. In this case, the orientation correction may be performed at each position hypothesis. The multi-hypothesis location estimation may comprise 1) applying a motion model for at least part of the position hypotheses based on the motion information, 2) orientation adjustment from the frame of reference of the PD 400 to the frame of reference of the building 100 (or to another predetermined frame of reference), 3) comparing the measured, orientation adjusted EMF vector (or computed feature vector) to the EMF vector (or computed feature vector) acquired from the map at position hypothesis, 4) determining probability of being a correct hypothesis for each position hypothesis on the basis of the comparison and optionally also on the basis of the reliability of the orientation adjustment, and 5) updating a posteriori probability distribution represented by the position hypotheses. Step 1-5 may be repeated without limit for a predetermined number of times, or as long as a certain threshold with respect to accuracy or characteristics of a posteriori probability distribution is met. At some point in time, the position hypotheses close to the correct position may have high probabilities, whereas the false positions may be associated with low probabilities (or lower probabilities). This way it may be determined, at each point of time, where the PD 400 is located in the building. Once the location estimates are converged, the tracking of the object, such as the PD 400, may be started. The orientation correction using the map data as the global reference may advantageously allow the multi-hypothesis location estimation to converge faster to the correct position/location hypothesis.
In an embodiment, the orientation correction is implemented, e.g., by applying an orientation filter for MARG (Magnetic, Angular Rate, and Gravity) sensor implementation in each position hypothesis. The MAR G sensor contains a three-axis magnetometer, a three-axis angular rate sensor, and a three-axis accelerometer. The orientation filter can be, e.g., a quaternion, gradient decent, Kalman filter (KF), or extended Kalman filter (EKF) based implementation, or a hybrid implementation. Each position hypothesis may maintain own orientation estimate, which is periodically updated, by the orientation filter, for each new sensor observation consisting of acceleration, angular velocity, and magnetic field measurements. For each update step, the true EMF vector F is used as the global magnetic field reference by the orientation filter. The vector F is acquired from the map at the location indicated by the specific location hypothesis, and is used by the orientation filter together with the sensor observation to update the orientation estimate of the specific location hypothesis.
In an embodiment as shown in
For example, let us assume that the low range communication unit 800 is the first RFID unit 800. Then, the PD 400 also comprising a second RFID unit 476 may read information comprised in the first RFID unit 800. The information may comprise the location of the first RFID unit 800, for example. Based on this information, the PD 400 may initialize its location estimate. The PD 400 may also activate the indoor navigation system, if not already to activated. The information may be comprised in the memory coupled to the first RFID unit 800, or the first RFID unit 800 may provide access information to a network element where the information is stored. Alternatively, the first RFID unit 800 may read information from the second RFID unit 476 of the PD 400, wherein the information may comprise network access address of the PD 400. Then network access equipment couple to the first RFID unit 800 may cause the initialization of the PD 400 with the location estimate and possibly with the EMF map data through the network. In either case, the data may also provide information enabling a network access establishment between the PD 400 and a network element, such as the database entity 500. The information may include network address of the PD 400 and/or the network address of the network element, such as the database entity 500.
In an embodiment, the low range communication unit 800 may be coupled to a controller 802 and to a calibration circuitry & correction circuitry for co-operating in calibration of the PD 400. For example, the exact magnitude of the EMF may be predetermined and stored in the memory 804. Then the PD 400 may apply this information in obtaining knowledge of how much the measured EMF magnitude deviates from the indicated, true EMV magnitude. Based on the information, a correction of the values provided by the magnetometer or calibration of the magnetometer may be in order. The calibration or correction process may be carried out in various manners. Let us consider the case where two RFID units are connected to each other. The second RFID unit 476 of the PD 400 may receive the true magnetic field information from the first RFID unit 800. Then the positioning device 400 may apply the received information in calibration of its magnetometer in order for the magnetometer to provide accurate and true EMF vector data. Alternatively, the positioning device 400 may apply the received information in correcting each value provided by the magnetometer so as to provide accurate and true EMF vector data. In another embodiment, the PD 400 may inform the correction that needs to be used for the EMF vector data received from this specific positioning device 400 to any element handling the EMF values provided by this specific positioning device 400. It should be clear that the difference between the true and measured EMF vectors may be determined at the positioning device 400 or at the first RFID unit 800, as the case may be. The calibration/correction may be for the strength of the EMF vector, and/or for an EMF bias (offset) vector affecting to the EMF measurements acquired by the positioning device 400. Alternatively, or in addition to, the calibration/correction may be for the direction of the EMF vector. The calibration process may also calibrate/correct data related to the direction and/or strength of the measured acceleration vector representing the direction of the gravitational force G. For this, the true value for may be previously determined for the predetermined location of the low range communication unit 800.
The exact location of the PD 400 after entry to the building 100 may be referred to as a control point. The control point may be any point at which the location of the PD 400 may be accurately known. Therefore, according to the embodiment explained with reference to
In an embodiment as shown in
In an embodiment, the EMF bias (offset) vector affecting to the EMF vector measurements acquired by the positioning device 400 may be determined based on the difference between the measured EMF vector and the true EMF vector at the location or at the location hypothesis of the positioning device 400, wherein the true EMF vector may be obtained from the EMF map of the building 100. Once the bias is determined, it may be added to or deducted from the measured value in order to obtain the correct EMF vector value, such as the correct magnitude of the EMF. The bias thus represents the difference of the measured value and the true value. It may be that the bias is caused by the equipment to which the PD 400 is mounted, or by a metallic object locating near (e.g. in a pocket or in a bag of a user) the PD 400. For example, when the PD 400 is mounted to the shopping cart, the cart may cause the same bias to the measured EMF values at each location of the building 100. Then it may be advantageous to first measure the bias at one predetermined location and then apply the bias in other places inside the building 100. The predetermined location may be detected as described above. Alternatively, the bias may be computed individually for each location hypothesis at the beginning of the location estimation process, and the bias estimate for each hypothesis may be updated incrementally/periodically during the location estimation and/or tracking process. It should be noted that this procedure may also aid in determining probabilities for the location hypothesis. For example, if the location hypothesis, where the bias is determined, is correct, the bias is properly determined and may increase the probability of the true location hypothesis due to correct, bias adjusted EMF vector observations. However, if the location hypothesis is not correct, the bias determined at that position may be false. This false bias may also lead to erroneous EMF vector observations from the point of view of the incorrect position hypothesis, which may decrease the probability associated with the false location hypothesis, and, thus, promote the correct location/position hypothesis, in addition or alternatively to the bias, a scaling factor may be similarly determined and applied. The scaling factor may be used to calibrate the magnetometer of the PD 400 so that it provides EMF vector magnitude values which are comparable to the EMF vector magnitude values provided by another measuring device used to generate the EMF map. In addition, if the bias and/or scaling factor are updated incrementally/periodically for each location hypothesis, the statistical properties, such as variance, of the bias/scaling factor estimates may further provide information about the correctness of the specific position hypothesis.
Embodiments, as shown in
The apparatuses 400 and 500 may further comprise radio interface components 456 and 506 providing the apparatus 400, 500, respectively, with radio communication capabilities with the radio access network. The radio interfaces 456 and 506 may be used to perform communication capabilities between the apparatuses 400 and 500. For the transmission and/or reception of information, the apparatuses may apply, for example, wireless cellular radio network. Alternatively, for example, short range radio communication techniques including wireless local area network and Bluetooth, may be applied. The radio interfaces 456 and 506 may be used to communicate data related to the EMF map, the measured EMF vectors, location estimation, initialization, etc.
User interfaces 458 and 508 may be used in operating the measuring device 400 and the database entity 500 by a user. The user interfaces 458, 508 may each comprise buttons, a keyboard, means for receiving voice commands, such as microphone, touch buttons, slide buttons, etc.
The apparatus 400 may comprise the terminal device of a cellular communication system, e.g, a computer (PC), a laptop, a tabloid computer, a cellular phone, a communicator, a smart phone, a palm computer, or any other communication apparatus. In another embodiment, the apparatus is comprised in such a terminal device, e.g. the apparatus may comprise a circuitry, e.g. a chip, a processor, a micro controller, or a combination of such circuitries in the terminal device and cause the terminal device to carry out the above-described functionalities. Further, the apparatus 400 may be or comprise a module (to be attached to the terminal device) providing connectivity, such as a plug-in unit, an “USB dangle”, or any other kind of unit. The unit may be installed either inside the terminal device or attached to the terminal device with a connector or even wirelessly. The apparatus 500 as the database entity may be comprised in the network accessible by the apparatus 400 of
As said, the apparatus 400, such as the positioning device, may comprise the at least one processor 452. The at least one processor 452 may comprise an indoor & outdoor navigation circuitry 460 for performing indoor or outdoor navigation. The indoor navigation may be on the basis of Earth's magnetic field measurement and EMF map, on the basis of RE signal strengths, and/or on the basis of visual or distance based location estimation. The circuitry 460 may also be responsible for identifying the correct position in the building 100 and to cause initialization of the PD 400 with the location estimate and/or with the at least part of the EMF map. The circuitry 460 may apply for example multi-hypotheses location estimation. A detection circuitry 462 may be for detecting a change in the operational environment of the PD 400 based on observing the first sequence 420 of
The magnetometer 470 may be used to measure the EMF vector. There may be various other sensors or functional entities comprised in the positioning device 400. These may include an inertial measurement unit (IMU) 472, an odometer 474, a low range communication unit 476, a GPS sensor 478, a radio frequency (RF) based location tracking sensor 480, at last one camera 482, for example. A skilled person understood that there may be of use when performing the embodiments as described earlier. For example, the RF based location tracking sensor 480 may detect the RE signal from a near-by base station and determine a location of the PD 400 based on the signal strength. The IMU 472 and the odometer 472 may be used to detect movement of the PD 400 and to enable three-dimensional orientation estimation of the PD 400. The IMU 472 may comprise for example acceleration sensor and a gyroscope, for example. The GPS sensor 478 may aid in outdoor navigation. The at least one camera 482 may be used to capture images for the purposes of any of the embodiments described. As shown in
Although not shown, the apparatus 400 may comprise a MARC sensor (described above) which may comprise or apply one or more of the functional entities of the apparatus 400, such as the magnetometer 470, an inertial measurement unit (IMU) 472, an odometer 474, etc.
The apparatus 500, such as the database entity, may comprise the at least one processor 502. The at least one processor 502 may comprise several circuitries. As an example, an indoor navigation circuitry 510 for performing indoor navigation on the basis of Earth's magnetic field measurement and EMF map, on the basis of RF signal strengths, and/or on the basis of visual or distance based location estimation. For the navigation, the memory 504 may comprise the EMF map 540 and the floor plan 542 of the building 100, for example, or have access to that information. The circuitry 510 may perform the location discovery and tracking based on measured EMF vectors acquired from the positioning device 400. Then the database entity 500 may indicate the position of the PD 400 within the building 100. Alternatively, the circuitry 510 may provide, on request: at least part of the generated indoor magnetic field map to the positioning device 400 that is to determine its location inside the building to which the EMF map is applicable. The indoor navigation circuitry 510 may provide the entire EMF map of the building 100 to the positioning device 400 via network. Alternatively, the indoor navigation circuitry 510 may provide only a part of the EMF map to the positioning device, to wherein the part of the generated indoor EMF map to provide is selected on the basis of location estimate of the positioning device. The location estimate may be acquired from a non-magnetic field based location discovery system. For example, if the building is equipped with another location discovery system, such as for example indoor base station based location discovery, the information provided by that other location technique may be used. Such additional data may obtained by the RE based location tracking unit 480 of the positioning device 400, transmitted to the database entity 500 and processed in the database entity 500, for example. The information stored relating to the other non-magnetic based navigation system may comprise the mounting location of the indoor base stations, for example. By knowing the location of the positioning device 400, at least roughly, the circuitry 510 may then provide EMF map only for the area where the positioning device 400 is currently moving, such as for the floor of the building where the positioning device 400 currently is. This may be advantageous so that only a part of the large EMF map needs to be communicated to the positioning device. The positioning device 400 may then use the map or part of the map in locating itself in the building 100. The circuitry 510 may also be responsible for identifying the correct position in the building 100 and to cause initialization of the PD 400 with the location estimate and/or with the at least part of the EMF map 540. The circuitry 510 may apply for example multi-hypothesis location estimator/tracker/filter.
A detection circuitry 512 may be for detecting a change in the operational environment of the PD 400 based on observing the first sequence 420 of
As may be understood by a skilled person from the description of the embodiments throughout the application and from
As used in this application, the term ‘circuitry’ refers to all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and/or digital circuitry, and (b) combinations of circuits and software (and/or firmware) such as (as applicable): (i) a combination of processor(s) or (ii) portions of processor(s)/software including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus to perform various functions, and (c) circuits, such as a nicroprocessor(s) or a portion of a microprocessors(s), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of ‘circuitry’ applies to all uses of this term in this application. As a further example, as used in this application, the term ‘circuitry’ would also cover an implementation of merely a processor (or multiple processors) or a portion of a processor and its for theft) accompanying software and/or firmware. The term ‘circuitry’ would also cover, for example and if applicable to the particular element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, or another network device.
The techniques and methods described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. For a hardware Implementation, the apparatus(es) of embodiments may be implemented within one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs) programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software: the implementation can be carried out through modules of at least one chip set (e.g, procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be implemented within the processor or externally to the processor. In the latter case, it can be communicatively coupled to the processor via various means, as is known in the art. Additionally, the components of the systems described herein may be rearranged and/or complemented by additional components in order to facilitate the achievements of the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art.
According to an embodiment, there is provided an apparatus comprising processing means configure to carry out an embodiment according to any of the
Embodiments as described may also be carried out in the form of a computer process defined by a computer program. The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, which may be any entity or device capable of carrying the program. For example, the computer program may be stored on a computer program distribution medium readable by a computer or a processor. The computer program medium may be, for example but not limited to, a record medium, computer memory, read-only memory, electrical carrier signal, telecommunications signal, and software distribution package, for example.
Even though the invention has been described above with reference to an example according to the accompanying drawings, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions Should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20125031 | Jan 2012 | FI | national |
This is a Continuation of application Ser. No. 13/734,365 filed Jan. 4, 2013, which in turn is a Non-provisional Application, which claims the benefit of Finnish Application No. 20125031 filed Jan. 11, 2012. The disclosure of the prior applications is hereby incorporated by reference herein in its entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 7181247 | Melick et al. | Feb 2007 | B1 |
| 7747409 | Ladetto et al. | Jun 2010 | B2 |
| 20060125644 | Sharp | Jun 2006 | A1 |
| 20070260418 | Ladetto et al. | Nov 2007 | A1 |
| 20080077326 | Funk et al. | Mar 2008 | A1 |
| 20090043504 | Bandyopadhyay et al. | Feb 2009 | A1 |
| 20110098921 | Miller et al. | Apr 2011 | A1 |
| 20120130632 | Bandyopadhyay et al. | May 2012 | A1 |
| 20120143495 | Dantu | Jun 2012 | A1 |
| 20120232838 | Kemppi et al. | Sep 2012 | A1 |
| 20130030700 | Miller et al. | Jan 2013 | A1 |
| 20130045751 | Chao et al. | Feb 2013 | A1 |
| 20130166195 | Bandyopadhyay et al. | Jun 2013 | A1 |
| Number | Date | Country |
|---|---|---|
| WO 2009021068 | Feb 2009 | WO |
| WO 2011065931 | Jun 2011 | WO |
| Entry |
|---|
| Serra, Indoor Pedestrian Navigation System Using Modern Smartphone, 2010. |
| Jul. 18, 2013 Office Action issued in U.S. Appl. No. 13/734,365. |
| Storms et al., “Magnetic Field Navigation in an Indoor Environment,” Proceedings of Ubiquitous Positioning Indoor Navigation and Location Based Service (UPINLBS), Oct. 2010. |
| Subbu et al., “Indoor Localization through Dynamic Time Warping,” Proceedings of IEEE International Conference on Systems, Man and Cybernetics (SMC), pp. 1639-1644, Oct. 2011. |
| Haverinen et al., “Global Indoor self-localization based on the ambient magnetic field,” Robotics and Autonomous Systems, vol. 57, pp. 1028-1035, 2009. |
| Riehle et al., “Indoor Waypoint Navigation via Magnetic Anomalies,” Proceedings of 33rd Annual IEEE International Conference of the Engineering in Medicine and Biology Society (EMBS), pp. 5315-5318, Sep. 3, 2011. |
| Gozick et al., “Magnetic Maps for Indoor Navigation,” IEEE Transactions on Instrumentation and Measurement, vol. 60, No. 12, pp. 3883-3891, Dec. 2011. |
| Glanzer et al., “Self-contained Indoor Pedestrain Navigation by Means of Human Motion Analysis and Magnetic Field Mapping,” Proceedings of 7th Workshop on Positioning, Navigation and Communication (WPNC), pp. 303-307, Mar. 2010. |
| Kemppi et al., “Use of artificial magnetic anomalies in indoor pedestrian navigation,” Proceedings of 72nd IEEE Vehicular Technology Conference (VTC), Sep. 2010. |
| Nov. 8, 2012 Finnish Search Report issued in Finnish Patent Application No. 20125031. |
| Nov. 8, 2012 Finnish Office Action issued in Finnish Patent Application No. 20125031. |
| Oct. 28, 2013 Office Action issued in Finnish Patent Application No. 20125031. |
| Number | Date | Country | |
|---|---|---|---|
| 20130310069 A1 | Nov 2013 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13734365 | Jan 2013 | US |
| Child | 13927854 | US |
