Access monitoring system and method for operating an access monitoring system

Abstract

In an access monitoring system (1) for a building, a gate (14) separates a restricted access area (20) from a public area (22). A radio device (6) is arranged at a certain distance from the gate (14) and defines a monitoring area. A control device (10, 12) of the system (1) is communicatively connected to a building device (16), and a data storage device (18) stores processing instructions for a situation-specific calibration mode. A signal processing device (8) evaluates radio communications in the monitoring area, thereby determining at least one situation indicator indicating a radio situation existing in the monitoring area, and for each radio device (6) detects a received signal strength indicator (RSSI) based on radio communications with a first mobile radio device (2). i The signal processing device (8) selects a calibration mode corresponding to at least one condition indicator and reads a processing instruction corresponding to the calibration mode from the data storage device (18). The signal processing device (8) determines the current position (P') of the first mobile radio device (2) as a detected received signal strength indicator (RSSI) according to the read processing instruction. i ) function.

Description

Technical Field

[0001] The technology described herein generally relates to an access monitoring system that allows authorized users to enter access-restricted areas in a building. Embodiments of the technology particularly relate to an access monitoring system having a transmitter and a receiver for radio signals and a method for operating such an access monitoring system. Background Art

[0002] Access monitoring systems can be designed in the most diverse ways. The design can, for example, involve the way in which the user (person) must prove his or her right to access, for example by means of a key, a magnetic card, a chip card or an RFID card or a mobile electronic device (such as a mobile phone). WO2010 / 112586A1 describes an access monitoring system in which a mobile phone carried by a user sends an identification code to an access node. If the identification code is found to be valid, the access node sends an access code to the mobile phone, which displays the access code on a display. If the user brings the mobile phone close to the camera so that the camera can detect the displayed access code, the access monitoring system checks whether the detected access code is valid. If the access code is valid, the user is allowed access. Summary of the invention

[0003] In buildings with many floors, there can be a large flow of people at certain times of the day, for example in the entrance hall of an office building, where a large number of employees enter the building in the morning or after their lunch break in order to reach their workplace. At these times, high demands are placed not only on the efficiency of the elevator systems installed in the building, but also on the access monitoring system, in order to, for example, avoid long queues at gates between public areas and areas with restricted access as much as possible. Therefore, there is a need for an access monitoring system that meets these requirements and which is still able to reliably distinguish between persons with authorized access and unauthorized persons.

[0004] One aspect of this technology relates to a method for operating a system for monitoring access to a restricted access area in a building, wherein a gate separates the restricted access area from a public area. The system includes a radio device, which is arranged at a certain distance from the gate and defines a monitoring area. The radio device is designed to perform radio communication with mobile radio devices within the radio range and corresponding to users, wherein a first mobile radio device at a first position of a first user is at a certain distance from each radio device. A control device of the system is connected in a communication manner to the building equipment, and a data storage device stores processing instructions for a situation-specific calibration mode. A signal processing device is connected in a communication manner to the data storage device, the radio device and the control device. The method evaluates the radio communication in the monitoring area and determines a situation indicator indicating the radio situation existing there based on the evaluation. For each radio device, an indicator is detected based on the received signal field strength of the radio communication with the first mobile radio device. The method selects the calibration mode corresponding to the situation indicator and reads the corresponding processing instruction from the data storage device. According to the read processing instruction, the current position of the first mobile radio device is determined as a function of the detected indicator for the received signal field strength.

[0005] Another aspect of the technology relates to a system for monitoring access to restricted access areas in a building, the system comprising a radio device, each of which is arranged at a certain distance from a gate and defines a monitoring area. The radio device is designed to perform radio communication with mobile radio devices within the radio range and corresponding to users, and a first mobile radio device at a first position of a first user is at a certain distance from each radio device. A control device of the system is connected to the building equipment in a communication manner, and a data storage device stores processing instructions for a situation-specific calibration mode. Signal processing device The data storage device, the radio device and the control device are connected in a communication manner. The signal processing device is designed to evaluate the radio communication in the monitoring area and determine at least one situation indicator therefrom, which indicates the radio situation currently existing in the monitoring area. In addition, the signal processing device is designed to, based on the radio communication with the first mobile radio device, detect an indicator for the received signal field strength for each radio device and select a calibration mode corresponding to the at least one situation indicator. The signal processing device is also designed to read the processing instructions corresponding to the selected calibration mode from the data storage device, and determine the current position of the first mobile radio device as a function of the detected received signal field strength indicator according to the read processing instructions.

[0006] The technology presented here proposes an access monitoring system in which, in order to determine the position, the radio conditions currently existing in the monitoring area are first determined and then a calibration mode is selected depending on the radio conditions. The selected calibration mode determines the processing instructions by means of which the current position of the user is determined. This allows the position determination to be flexibly adapted to the existing radio conditions so that the position can be determined as accurately as possible even in the presence of radio conditions.

[0007] For example, when traffic is high, many users may interfere with the propagation of the radio signal, resulting in increased signal attenuation and signal obstruction. Therefore, the radio signal may propagate differently in this case than during a baseline case where a single user moves along a determined baseline path. Therefore, processing instructions based on this baseline case may not provide the most accurate position determination. Therefore, in one embodiment, a calibration mode may be selected that takes into account higher traffic. On the other hand, if traffic is low, processing instructions may be based on the baseline case.

[0008] The number of users can also indicate the number of active mobile radios present in the monitoring area. Therefore, in one embodiment, the number of mobile radios can be selected as a status indicator. As an alternative or in addition to the number of mobile radios, at least one of the following status indicators can be selected, depending on the configuration of the access monitoring system, for example, depending on the situation in the building: mobile radio type, spatial orientation of the mobile radio, entry position of the user in the monitoring area, sensor data generated by the mobile radio, time, number of radio devices, computing power available in the access monitoring system, density of radio devices or room size. These options allow building-specific adaptation.

[0009] The technology presented here detects a large number of received signal strength indicators and processes these received signal strength indicators according to a calculation model, wherein the calculation model depends on the selected calibration mode. Advantageously, the received signal strength indicator is easy to determine and the determination and monitoring of the received signal strength indicator are provided in known radio communication specifications and standards. In these specifications and standards, the received signal field strength indicator is also called the received signal strength indicator (RSSI). Exemplary standards relate to Bluetooth technology, such as low-power Bluetooth (BLE) technology.

[0010] In one embodiment of the technology presented here, the radio signals are sent and evaluated based on Bluetooth technology, in particular BLE technology. This has the advantage that the technology is generally available for mobile radio devices and that users can also use devices they are familiar with in conjunction with the access monitoring system. This is done in a convenient way for the user, because, for example, the user does not have to handle the mobile radio device when he wants access.

[0011] The data storage device stores data determined in the calibration phase, which data can be read in the application phase. The data, for example, relate to radio signal strength reference values, which are determined in the calibration phase from radio communication between one of the radio devices and a reference mobile radio device arranged at a reference distance therefrom. The data can also relate to a reference radio signal pattern as a function of the position of the reference mobile radio device, which is determined in the calibration phase by radio communication of the radio device with the reference mobile radio device. Furthermore, the data can relate to a loss coefficient determined in the calibration phase as a function of the reference position of the reference mobile radio device for each radio device.

[0012] In one embodiment, the first processing instruction of the first calibration mode for position determination may be determined according to the following formula:

[0013]

[0014] Among them, N A represents the number of radio devices and d i (p) represents the Euclidean distance between the i-th radio device (6) and the variable position (p) of the user (4), wherein the distance (d′) between the radio device (2) and the i-th radio device (6) is determined by means of the reference radio signal pattern (FP). i ) is obtained as follows:

[0015]

[0016] The loss factor is defined as follows:

[0017]

[0018] Where j = 1, ..., N j，k represents the jth measurement for the ith radio device in the kth trip partition of a determined trip segment, the trip partition being determined during the calibration phase.

[0019] In one embodiment, a second processing instruction for a second calibration mode can determine the acquisition of a user's movement trajectory, which is based on the determined position of the radio device, the detected indicator of the received signal field strength and the radio signal strength reference value, wherein a loss coefficient is determined by means of maximum likelihood estimation, the determined loss coefficient is introduced according to a negative log-likelihood function to determine a residual consumption (Restkosten), and the residual consumption on the position path is minimized.

[0020] In one embodiment, the data storage device also stores an individual identifier of the first mobile radio device, which is sent by the first mobile radio device. The individual identifier is used to infer the user who owns the first mobile radio device. In one embodiment, it can thus be checked whether the user is authorized to access. In the access monitoring system, the signal processing device is designed to feed a control signal to the control device when a certain rule is met based on the identifier and the determined current position of the mobile radio device. The control device is designed to trigger a building action corresponding to the determined rule, in particular the opening of a gate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In the following, different aspects of the improved technology are explained in more detail based on embodiments and in conjunction with the accompanying drawings. In the drawings, the same elements have the same reference numerals, wherein:

[0022] Figure 1 A schematic diagram showing an exemplary situation in a building with an access monitoring system according to one embodiment;

[0023] Figure 2 Shown in the building Figure 1 A schematic diagram of an exemplary radio communication situation for the situation shown;

[0024] Figure 3 Shown for Figure 1 An exemplary illustration of a model for determining a user's position in the illustrated case, including exemplary influencing factors;

[0025] Figure 4 A flow chart illustrating an embodiment of a method for operating an access monitoring system;

[0026] Figure 5 A flow chart illustrating an embodiment of a calibration method for determining a reference constant;

[0027] Figure 6 A flow chart illustrating an embodiment of a calibration method for determining a loss coefficient;

[0028] Figure 7 A flow chart showing another embodiment of a method for operating an access monitoring system, and

[0029] Figure 8 A flow chart showing an additional exemplary embodiment of a method for operating an access monitoring system. DETAILED DESCRIPTION

[0030] Figure 1is a schematic diagram of an exemplary situation in a building with an access monitoring system 1. For reasons of illustration, only a part of the walls 3 of the building, the room 24 and the areas 20, 22 are drawn. The room 24 can be, for example, an office, an apartment, a hall and / or an elevator car of an elevator system. Figure 1 In the case shown, there is a user 4 in the area 22, who carries with him a mobile radio device 2. In such an exemplary case, the area 22 is not subject to any access restrictions and is also referred to below as the public area 22. The gate 14 separates the public area 22 from the area 20, which is subject to access restrictions and adjoins a room 24. The area 20 is also referred to below as the access-restricted area 20. The person skilled in the art knows that, depending on the building, each room 24 can be regarded as an access-restricted area 20. In the present description, the term "building" is to be understood as meaning, for example, residential and / or commercial buildings, sports stadiums, airports, ships.

[0031] According to one embodiment, the access monitoring system 1 includes a radio device 6, for example, four radio devices 6 marked with RF1, RF2, RF3, and RE4 may be arranged. It is known to those skilled in the art that in another embodiment, more than four radio devices 6 (generally RF1, RF2, RF3, and RF4) may be arranged. i , where i = 1, 2, ... N), which is Figure 1 Each radio device 6 sends and receives radio signals during operation according to a determined standard for radio communication, as described elsewhere in this specification.

[0032] The radio device 6 is arranged in a fixed position at a certain position; these positions can be indicated according to the building plan, for example, by xy coordinates for the building floors. The position of the gate 14 can be indicated for the building floors in a similar manner by xy coordinates. In one embodiment, data indicating the position of the radio device 6 and the position of the gate 14 are stored in the access monitoring system 1, for example, in a data storage device 18 (hereinafter also referred to as storage device 18).

[0033] The area monitored by the access monitoring system 1 is determined by the radio device 6 arranged in this way, which area is referred to as the monitoring area in the following. Depending on the building situation, the monitoring area can be adjacent to the main entrance door, the floor door or the elevator door, for example, the position of the main entrance door, the floor door or the elevator door is also indicated in the building plan and is therefore known. If the user 4 enters the monitoring area through such a door, for example, the movement of the door can be detected, and the current position of the user 4 is inferred based on the known position of the door. Since the user 4 is moving away from the door, the current position can be used as the starting position for observing the movement in the monitoring area. In one embodiment, the radio device 6 can be located in a prominent position, for example at the door, so as to define this position as the starting position.

[0034] The access monitoring system 1 further comprises a signal processing device 8 (shown as a DSP) and control devices 10, 12 connected to the signal processing device 8. A storage device 18 is also connected to the signal processing device 8. The signal processing device 8 is communicatively connected to the radio device 6, which is indicated by a double arrow 9. The control devices 10, 12 comprise a control system 12 (in Figure 1 The access control system may be a control device 16 (CTRL) for a gate 14 or a control device 16 (CTRL) for an elevator system (in FIG. Figure 1 10 is a control system 10 shown as ECS in FIG. 10. With respect to the elevator system, some or all of the rooms 24 shown are elevator cars. Figure 1 In the embodiment, the control devices 10, 12 comprise a control system 10 for an elevator system. It will be appreciated by those skilled in the art that the control system 12 for the access monitoring system 1 and the control system 10 for an elevator system may be separate systems and may therefore be denoted as separate systems.

[0035] exist Figure 1 In the case shown, the technology presented here can be used in an advantageous manner to operate the access monitoring system 1 with the lowest possible complexity and to allow the user 4 to conveniently access the access restricted area 20. It is known to those skilled in the art that there may be more than one user 4 in the monitored area. Briefly summarized by way of example, the operation of the access monitoring system 1 is carried out according to the following embodiment:

[0036] The technique determines the position of the user 4 using a calculation model, also referred to below as a channel model, which represents the transmission loss of the radio signal propagating between the mobile radio device 2 and the radio device 6. As a measure of the transmission loss, the channel model uses received signal strength indicators (RSSI), which are determined for the current position associated with each radio device 6. The channel model is adapted according to the radio conditions present in the monitoring area, such as a plurality of existing mobile radio devices 2, their types (e.g., iPhone devices or Android devices) and / or direction information (e.g., the position / orientation of the mobile radio device 2), and the condition indicators determined thereby. The adaptation is performed according to the calibration mode selected for the radio conditions; the selected calibration mode can be based on previously determined and stored values ​​(e.g., reference values), or such a previous value determination may not be performed. The technique implemented in the access monitoring system 1 improves the accuracy of the position determination. In one embodiment, the improvement in accuracy is promoted in the following way, the radio signal is sent according to the Bluetooth technology standard and / or the best possible diversity is provided in the access monitoring system 1 (as explained in other parts of the description).

[0037] Since the position of the radio device 6, in particular the position with respect to the reference gate 14, is known / determined, the position of the user 4 relative to the radio device 6 or the gate 14 is determined by the position determination in the mobile radio device 2. This determines, for example, the distance of the user 4 from the gate 14 and / or the direction of movement, for example, towards the gate 14 or away from the gate. The radio signal sent by the mobile radio device 2 includes a personal identifier (e.g. device ID, serial number, device address), by means of which it can be checked whether the user 4 is authorized to access and whether the user wants to access and not just pass through the gate 14. If the user 6 is walking along Figure 1 If the user 4 moves in one of the travel segments 26, 28 shown as an example in FIG. 1 , the position of the user 4 over time (also called trajectory) can be tracked. For this purpose, the position determination is performed at fixed discrete time intervals; for example, the time intervals can be selected based on radio technology. If the comparison of the acquired position with the position of the gate 14 shows that the user 4 is at the gate 14, then if a certain rule is met, a corresponding building action is triggered; for example, if an access authorization is determined, access is granted to the user.

[0038] The channel model and the options for customizing the channel model are described in more detail below. In addition, other features of the access monitoring system 1 and its components are also provided.

[0039] In the embodiment shown, the radio device 6 of the access monitoring system 1 is arranged in the public area 22 and in the access restricted area 20. Thus, the monitoring area extends over both areas 20, 22. Figure 1 In the case shown with four radio devices 6, two radio devices 6 (RF1, RF2) are in the public area 22 and two radio devices 6 (RF3, RF4) are in the restricted access area 20. It is known to those skilled in the art that in another embodiment, the radio devices 6 can only be arranged in one of the two areas 20, 22, and the number and arrangement of the radio devices 6 can be selected according to the conditions in the building. The arrangement of the radio devices 6 in the two areas 20, 22, i.e. on both sides of the gate 14, is advantageous in that the position is determined with substantially the same accuracy regardless of the direction in which the user 4 moves.

[0040] The gate 14 separates the restricted access area 20 from the public area 20. Depending on the building and its requirements, the gate 14 can be a physical barrier, such as a door, a revolving door or a sliding door, a barrier or a revolving door, or be designed without such a physical barrier. The access monitoring system 1 uses the gate 14 to ensure that only authorized users 4 can enter the access restricted area 20, for example by blocking or opening the physical barrier. In the case of a gate 14 without a physical barrier, the access monitoring system 1 can monitor access, for example by activating security measures when an unauthorized user 4 enters the access restricted area 20, such as, for example, activating an optical and / or acoustic alarm; alternatively or additionally, a notification of a security service can be triggered. Regardless of whether the gate 14 is equipped with a physical barrier, any information device that may be present can be activated in order to, for example, notify the user 4.

[0041] Figure 2 Shown in the building Figure 1 Schematic diagram of an exemplary radio situation for the illustrated situation. Figure 1 and Figure 2 In the example shown in FIG. 1 , the user 4 is in position P, hereinafter referred to as (actual) position P. The technology presented here uses a channel model to determine the position of the mobile radio device 2 and thus the position of the user 4. The position of the user 4 determined in this way is referred to as position P' in the following; this position can be identical to the actual position P of the user 4, but can also deviate to a greater or lesser extent under actual conditions, especially in buildings.

[0042] exist Figure 1 and Figure 2 , four radio devices 6 (RF1, RF2, RF3, RF4) are shown, which are arranged in the area around the gate 14. The user 4 and the mobile radio device 2 are in a (real) position P, from which the user is at a certain distance from one of the radio devices 6; Figure 2 These are the distances d1, d2, d3, d4 (usually d i , where i = 1, 2, ... N). Figure 2In the example, it is assumed that radio signals are sent and received between the mobile radio device 2 of the user 4 and each radio device 6. For each of these radio signals, a received signal strength indicator (RSSI) at the position P can be determined. i );exist Figure 2 In this example, the received signal strength indicators RSSI1, RSSI2, RSSI3, and RSSI4 are shown. Figure 2 For each radio signal or each radio link a value pair is plotted which indicates the distance d i and the received signal strength indicator RSSI measured for it i , i=1, 2, ..., N (the number of radio devices 6).

[0043] A characteristic radio pattern FP (also called radio fingerprint FP) corresponding to the position P of the user 4 is generated based on these radio signals. In one embodiment, the radio fingerprint FP includes all received signal strength indicators RSSI measured for the position P. i ,exist Figure 2 In the example, this refers to four received signal strength indicators RSSI1, RSSI2, RSSI3, RSSI4. If the position P changes, one or more of these received signal strength indicators RSSI1, RSSI2, RSSI3, RSSI4 will usually change. In one embodiment, for the received signal strength indicator RSSI measured for the position i , that is, the knowledge of the radio fingerprint FP determined for this position can be used to approximately determine the position of the mobile radio device 2. Received signal strength indicator RSSI i The and radio patterns FP may be stored in the storage device 18 .

[0044] Figure 2 A situation for determining one or more reference values ​​according to an embodiment is also shown. One or more reference values ​​determined in this way can be used in a calibration mode. In the situation shown, the user 4 has a reference mobile radio device 2a and is at a distance d0 from the radio device 6 selected for determining the reference value; Figure 2 In this example, this is the radio device 6 labeled RF1, for which the reference value determined is denoted by Further information on this is given elsewhere in this specification.

[0045] It is known to those skilled in the art that the highest possible degree of diversity can be achieved in various ways. In communication technology, diversity techniques are used for redundant transmission of data via random independent channels, which are subject to errors only with a very low probability at the same time. Various forms of diversity operating modes are known: For time diversity, the information in the useful data is time-shifted several times and thus sent several times via the same radio channel to compensate for time-related fluctuations in the signal strength. In the case of spatial diversity, two or more transmit-receive paths are operated. This is mainly achieved by spatially separated antennas operating in parallel. Depending on the method, the receiving device then selects, for example, the strongest received signal. For frequency diversity, the same signal is transmitted simultaneously via two or more different carrier frequencies. If interference occurs or the signal is completely blanked, it is expected that not all used frequency ranges will be affected by this.

[0046] In one embodiment of the technology presented here, radio communication between the mobile radio device 2 (or the reference mobile radio device 2a) and the radio device 6 is carried out according to the standard for Bluetooth technology, such as Bluetooth Low Energy (BLE) (hereinafter referred to as BLE technology); the mobile radio device 2 (2a) and the radio device 6 are equipped with corresponding equipment for this. As an alternative to BLE technology, other known radio technologies can be used, such as a WLAN / WiFi technology. The mobile radio device 2 sends an attention notification from a so-called advertising event, for example, as a radio signal. All radio devices 6 located within the radio range receive the radio signal, and each of these radio devices 6 can determine the signal strength of the radio signal received by it, thereby generating a received signal strength indicator RSSI. i It is known to those skilled in the art that the process can also be carried out in reverse, that is, each radio device 6 sends an advertising event as a radio signal and the mobile radio device 2 determines the signal strength or received signal strength indicator RSSI based on it. i (Further explanation is given below).

[0047] In one embodiment of the BLE technology (Bluetooth 5.0), three main radio channels are used, each with a relatively small bandwidth and separated by relatively large frequency intervals from each other; further details of the BLE technology, in particular the details of the communication protocol, are known to those skilled in the art, so it does not seem necessary to explain them at this point. In one embodiment, diversity can be achieved by averaging consecutive measurements of the received signal strength indicator RSSIi. The diversity is generally independent of time, because the diversity is transmitted via different radio channels and therefore on different frequencies.

[0048] It is known to those skilled in the art that the received signal strength indicator RSSI iThe signal strength indicator RSSI may be measured by the mobile radio 2 (or the reference mobile radio 2a) and / or the radio 6 or the signal processing device 8. For example, in the first case, the radio 6 may continuously send advertising event packets. The mobile radio 2 receives these packets and may determine all received signal strength indicators RSSI associated therewith. i The measured values ​​are now available in the mobile radio device 2. The software application (also referred to as application) can now determine the position of the mobile radio device 2 according to the technology presented here and possibly also use the sensor values ​​(IMU data) generated by the sensor module (IMU, Inertial Measurement Unit) of the mobile radio device 2, since these are also available on the mobile radio device 2. The determined position is then communicated to the access monitoring system 1 by the mobile radio device 2.

[0049] In the opposite (second) case, the mobile radio 2 continuously sends advertising event packets. The radio 6 receives these packets and can determine all received signal strength indicators RSSI associated therewith. i The measured values ​​are now present in the radio device 6 and can be stored with a time stamp in the memory device 18. The signal processing device 8 processes these data according to the technology described here to determine the position of the mobile radio device 2. The IMU data can be transmitted from the mobile radio device 2 to the signal processing device 8 and also used to determine the position. The following is a technical description based on the second case.

[0050] Figure 3 Shown for use according to Figure 1 and Figure 2 Schematic diagram of an exemplary principle for determining the position of the user 4 in the situation shown. The position determination is based on a channel model (box 38). Depending on the design, one of several calibration modes can be used to determine the position (box 36), wherein the calibration mode can be selected based on the situation indicators. The position determination scheme can also be modified using time filtering (box 34) and / or sensor values ​​(box 32). In one embodiment, the sensor values ​​are generated by a sensor module (IMU, inertial measurement unit) of the mobile radio device 2. The current position P' of the mobile radio device 2 (which may have been modified by filtering and sensor values) is obtained based on the channel model adapted according to one of the calibration modes, which is Figure 3 The position P' is in the xy plane (see Figure 1 ) is represented in frame 40. In frame 40, gate 14 is located at x0 in the x direction, for example; it can also be seen from this that the position determination according to the technology presented here extends over two areas 20, 22.

[0051] The technique presented here is based on the concept of representing the loss of signal strength during transmission on a transmission channel. The transmission channel comprises the signal path from the mobile radio 2 (including its antenna) through the air to one of the radio devices 6 (including its antenna), which may also result in losses. In the technique presented here, antenna losses and multipath propagation are considered as random variables. Figure 1 and Figure 2 It can be seen that multiple signal paths start or end at the mobile radio device 2. This concept is known to those skilled in the art as a channel model. According to the channel model used here, the average received signal strength indicator RSSI (d) (in dBm) as a function of the distance d is expressed by the following equation:

[0052]

[0053] in

[0054]

[0055] and

[0056] W=X+S+G=10log 10 (x)+10log 10 (s)+10log 10 (g)

[0057] in:

[0058] d0: reference distance

[0059] α: Loss coefficient / loss index

[0060] Average received signal strength indicator at the reference distance d0

[0061] The average power received at the reference distance d0

[0062] X: attenuation variable / decay variable,

[0063] S: radio obscuration variable, and

[0064] G: Antenna gain variable / antenna loss variable.

[0065] At a given point in time, there are instantaneous radio conditions in the monitoring area (here only the radio signals between the mobile radio device 2 and the radio device 6 (Bluetooth technology) are taken into account, and other possible radio signals present in the building are not taken into account). Since each mobile radio device 2 also emits at least one unique identifier via the radio signal, the mobile radio devices 2 can be distinguished; this allows conclusions to be drawn about the number of active mobile radio devices 2 present in the monitoring area. The identifier can be a telephone number, an International Mobile Radio Subscriber Identity (IMSI), an equipment ID (International Mobile Station Equipment Identity (IMEI)), a device address (Media Access Control (MAC) Address) or another type of unique or one-to-one identifier of the mobile radio device 2. The degree of radio shadowing and the channel utilization of the current user 4 can be estimated from the number of mobile radio devices 2. In addition, it can be identified, for example, based on the number of users 4, Figure 2 The user 4 in the mobile radio 2 is closer to the radio device RF1 or the oppositely arranged radio device RF2. In an embodiment, the type of mobile radio device 2 can also affect the radio conditions. The device ID usually indicates the type of mobile radio device 2 (e.g. iPhone from Apple or so-called Android smartphones from other manufacturers).

[0066] As well as the types of mobile radio devices 2, the number of mobile radio devices 2 represents a status indicator. Further status indicators are the entry position of the user 4 into the monitoring area (e.g. the prominent position mentioned), sensor data generated by the mobile radio device 2, the user identifier, the time, the number of radio devices 6, the (computer) computing power available in the access monitoring system 1, the density of the radio devices 6 and the size of the room. By evaluating the radio communication in the monitoring area, at least one of these status indicators can be determined, which indicates the radio situation in the monitoring area. It is known to the person skilled in the art that several of these status indicators can be recorded to display the radio situation and that not all of the mentioned status indicators can be determined in the access monitoring system 1, at a specific time or for a specific mobile radio device 2.

[0067] According to the techniques presented here, the condition indicator is used to select a calibration mode appropriate to the conditions, by which the channel model is adapted. Three different calibration modes, each with several possible calibration algorithms, are described below:

[0068] A calibration mode based on a reference mobile radio device, which is based on a dedicated calibration run with the reference mobile radio device 2a in a calibration phase and is combined with the following Figure 6 Make an introduction;

[0069] A calibration mode independent of the mobile radio device based on a self-calibration method during the calibration phase; and

[0070] Automated real-time calibration mode that can be performed smoothly with reduced or no special calibration phase.

[0071] The parameters of the channel model mentioned, in particular the average received power (P R，d0 ), which may vary greatly for different radio conditions and mobile radio devices 2. However, for reliable position determination, knowledge of these parameters is important for a given system and given radio conditions, especially in the case of changes in the propagation environment of the radio signals. By means of the calibration mode mentioned, the parameters can be determined in a calibration phase with or without knowledge of the path of the user 4, or the calibration phase can be omitted.

[0072] First, reference is made to a calibration mode that is independent of the mobile radio, also referred to below as self-calibration. Here, the loss factor α describing the path loss is determined based on measurements between the radio devices 6 and knowledge of the position of the radio devices 6. i During the calibration phase, each radio device 6 acts as an individual transmitter, while the remaining radio devices 6 are receivers. When, for example, the first radio device 6 sends a radio test signal to all other radio devices 6, the received signal strength indicator RSSI determined by them i is stored. Then, the first radio device 6 that previously transmitted switches to receiver mode and the next radio device 6 starts transmitting. This process is repeated until all radio devices 6 have transmitted the radio test signal once. Based on the knowledge of all positions of the radio devices 6 and the distances between the radio devices 6, the received signal strength indicator RSSI is determined. i is used to determine the corresponding loss factor α for all radio devices i The advantage of self-calibration is that it can be automated with little effort and repeated when necessary, for example as the environment changes. Self-calibration can be used, for example, to determine the position of the mobile radio device 2 when it is located in the vicinity of the radio device 6 due to building conditions (e.g. a building door leads directly into the surveillance area); this can be done, for example, by means of the radio fingerprint detection in order to select the self-calibration mode.

[0073] The advantage of the automated real-time calibration mode is that it requires little or no prior knowledge, which reduces the installation effort. In one embodiment, the automated real-time calibration mode can be run without a special calibration phase. The position of the mobile radio 2 is determined without prior knowledge other than the position of the radio 6. Instead of estimating the parameters of the channel model used to determine the position in a previous calibration phase, these parameters are considered interference parameters and are determined in real time together with the position of the mobile radio 2. This method does not necessarily require calibration, since the corresponding optimization does not depend on the reference RSSI value or the loss factor α. i Thus, the algorithm can adapt to new propagation environments or antenna patterns of the mobile radio device 2. In one embodiment, if only the loss coefficient α i is regarded as an interference parameter, and the average received signal strength indicator at the reference distance d0 If the θ is known, the accuracy can be improved. In one embodiment, the automated real-time calibration mode determines the movement trajectory from the start of the measurement to the current time point.

[0074] In another embodiment, the automated real-time calibration mode is iterative; it is based on the assumption that the first position of the user 4 is known. As described above, this may be the case when the user 4 enters the monitoring area directly through a landing door or elevator door and continues to move from this initial position. i The loss factor α can be determined for each radio device 6 i The loss factor α determined in this way i This is then used to determine the (new) position of the user 4. This new position is then determined based on the two received signal strength indicators RSSI of each radio device 6: i Determine the new loss factor α i This process is then continued iteratively for the entire travel segment.

[0075] In another embodiment of the automated real-time calibration mode, the (old) data obtained by the iterative process can be used for expansion in order to initially achieve a certain minimum stability of the position determination. The algorithm is based on older and outdated information about the loss factor α. Although these can lead to inaccuracies in the position determination, their accuracy is generally better than the initial position determined by the iterative procedure at the beginning of the run. For example, the first 10-30 measurements, in particular the first 20-25 measurements, can be used. This number of measurements is sufficient to obtain a preliminary and stable position for a correct estimate of the loss factor α.

[0076] In one embodiment of the access monitoring system 1, a calibration phase is provided, which is performed, for example, when the access monitoring system 1 is put into operation on site. In this calibration phase, the reference constant (mean value M (RSSI d0 )) and several loss coefficients α i As an alternative to calibration during commissioning on site, it is possible to calibrate the radio devices 6 in a structurally identical manner and in particular with respect to the reference constant M(RSSI d0 ) have essentially the same radio characteristics, for example when the manufacturer or supplier of the access monitoring system 1 is the same, the calibration can be performed centrally. If necessary, the calibration phase can be repeated after commissioning.

[0077] The calibration mode based on the reference mobile radio device 2a is explained below. In this case, during the calibration phase, the reference mobile radio device 2a is guided along a determined travel section (with known position information) and receives a signal strength indicator RSSI i is measured and stored together with the known position information. Here, it is not necessary to know the travel segment exactly, it is sufficient to roughly determine the starting point, the end point and the constant speed between the starting point and the end point. In one embodiment, the method is extended to divide the travel segment into separate travel sub-segments (k) so that different loss coefficients α are determined for the path loss of each radio device 6 and each travel sub-segment (k). i For a user 4 whose location is to be determined, the algorithm selects the trip segment (k) in which the user 4 is likely to be located (determined by the radio fingerprint) and accordingly assigns a loss coefficient α to each radio device 6 for the corresponding trip segment (k). Figure 5 Give further explanation.

[0078] Figure 4 A flow chart showing an embodiment of a method for operating an access monitoring system 1, wherein the location of a user 4 is determined in an application phase. For the flow charts shown in the present application by individual steps, the division generally applicable to the steps shown is exemplary, and in another illustration, one or more of these steps can be divided into one or more sub-steps or a plurality of steps can be combined into one step. Therefore, the selected illustration of the flow chart should not be understood as limiting.

[0079] like Figure 1 and Figure 2As shown in the example in , a user 4 carrying a mobile radio device 2 is near the gate 14. Although only user 4 is shown, it is known to those skilled in the art that other users and mobile radio devices may be present. The Bluetooth function of the mobile radio device 2 and any associated software applications are activated, and the calibration phase is completed. The storage device 18 is configured for the technology described here; in particular, the storage device stores building data (such as a building floor plan or floor plan) and processing instructions for the mentioned situation-specific calibration mode. The processing instructions include algorithms for various calibration modes, algorithms for determining location, and data determined in the calibration phase (such as a reference distance d0, a reference radio signal pattern, a reference received signal strength indicator). It is known to those skilled in the art that the storage device 18 also stores (online) data determined in the application phase.

[0080] The user 4 moves, for example, along the travel section 26 from the public area 22 in the direction of the restricted access area 20. It is assumed that the mobile radio device 2 is already within the radio range (RF1-RF4) of the radio device 6. The method starts at step T1 and ends at step T6.

[0081] In step T2, the radio communications in the monitoring area are evaluated by the signal processing device 8. For the technology presented here, such radio communications refer to all radio signals (Bluetooth technology) transmitted and considered in the monitoring area. For example, the radio signals transmitting the above-mentioned attention notifications (advertising events) and the radio signals of their responses. The signal processing device 8 thereby determines, for example, the identifier of the mobile radio device 2 present.

[0082] The signal processing device 8 also detects the signal strength of the radio signal received by the radio device 6 and / or the mobile radio device 2 present. In one embodiment, the signal processing device 8 detects a received signal strength indicator RSSI based on the radio communication with the mobile radio device 2 for each radio device 6. i .

[0083] In step T3, the signal processing device 8 determines at least one situation indicator, which is indicative of the radio conditions existing in the monitoring area. The situation indicator is determined based on the evaluation performed in step T2. Exemplary situation indicators are described above.

[0084] In step T4, at least one calibration mode corresponding to the condition indicator is selected. To this end, at least one rule is determined in the access monitoring system 1, in particular in the computer program and / or in the processor of the signal processing device 8. A person skilled in the art will know that a plurality of rules can be established. An example of such a rule is given below:

[0085] If the situation indicator indicates, for example, the type of mobile radio device 2 and the entry point into the monitoring space, a check is performed to determine whether a calibration data set (processing instructions) for a calibration mode for a reference mobile radio device is present in the storage device 18. This calibration mode can be selected in particular if the entry point is the starting point for a calibration run.

[0086] If the situation indicator indicates a user identifier and a time instead of or in addition to the situation indicator present in the previous rule, it is checked whether a position determination according to the calibration mode has already been performed at a similar time for this user 4. If this is the case, the calibration mode can be selected again.

[0087] If the situation indicator indicates that the number of users 4 in the monitoring area is significantly higher than that already present during the calibration run, a calibration mode independent of the mobile radio (self-calibration) or an automated real-time calibration mode is provided, for example.

[0088] If the situation indicator indicates radio conditions that do not appear to have calibration data sets suitable for a special calibration mode, then a calibration mode independent of the mobile radio (self-calibration) or an automated real-time calibration mode is provided, for example. However, if, for example, the situation indicator indicates the time and it is known that this corresponds to a peak time when many users 4 are present, then self-calibration can be selected, since it can adapt to changing environmental conditions.

[0089] Depending on the situation in the building, the access monitoring system 1 or its computer system can be more or less fully loaded or have less or more computing power. When the computing power provided is used as a situation indicator, for example if the computer system has sufficient available computing power, a more computationally intensive automated real-time calibration mode can be selected.

[0090] Those skilled in the art will appreciate that other rules and / or additional rules may be established.

[0091] If the calibration mode is selected, the signal processing apparatus 8 reads the processing instructions corresponding to the calibration mode from the data storage device 18 .

[0092] In step T5, the position P' of the first mobile radio device 2 is determined based on the read processing instructions. Figure 7 The embodiment described herein determines the position. Figure 7 , an embodiment of using the determined position P' is also given. The method ends in step T6.

[0093] Figure 5 Shown is the reference constant used to determine Flow chart of an embodiment of a calibration method for the average value of the reference constant; this average value of the reference constant is called M(RSSI d0 ). Reference Figure 1 and Figure 2 The illustrated situation describes a calibration method, using in the calibration phase a reference mobile radio device 2a (which may be identical to the mobile radio device 2). The method starts in step S1 and ends in step S6.

[0094] In step S2, a reference distance d0 is determined. The reference distance d0 is the distance between the reference mobile radio device 2a and the selected radio device 6 (in Figure 1 The reference distance d0 is preferably equal to or less than 1 meter; in one embodiment, d0=1 meter. If the reference distance d0 is selected, the reference mobile radio 2a is located at the above distance from the selected radio 6.

[0095] If the reference mobile radio device 2a and the selected radio device 6 are switched on so that they carry out radio communication according to the BLE technology, a number of received signal strength indicators RSSI are determined in step S3. d0 In one embodiment, each received signal strength indicator RSSI is measured in relation to the radio signal arriving at the radio device 6. d0 While the reference distance d0 remains unchanged, the reference mobile radio device 2a is rotated or moved around the selected radio device 6. As a result, the antenna of the reference mobile radio device 2a adopts different antenna orientations (angular diversity) relative to the selected radio device 6. In addition, this leads to a higher (spatial) diversity. After each change in antenna orientation, at least one received signal strength indicator RSSI d0 is determined and stored in the storage device 18. The number of measurements and the number of antenna orientations may be specified in the calibration specification.

[0096] If a certain measurement is performed in step S3, then in step S4 the received signal strength indicator measured and stored in step S3 is determined. The average value (in dBm). Reference constant RSSI d0 The average value M(RSSI d0 ) is stored in the memory device 18 in step S5 and used for position determination in the application phase. The reference mobile radio device 2a and the selected radio device 6 can then be deactivated and the method ends in step S6.

[0097] Figure 6 A flow chart showing an embodiment of a calibration method for determining the loss factor α is shown. Figure 1 and Figure 2The calibration method is described with reference to the situation shown in FIG. 1 and the reference mobile radio device 2 a. The method starts with step A1 and ends with step A9 .

[0098] In this calibration method, a large number of measurements of the received signal strength (RSSI measurements) are performed while the reference mobile radio device 2a is moving along a determined travel section in a building. For this purpose, a travel section for given conditions in a building is determined in step A2. For the calibration, for example, one can select Figure 1 The travel section 26 is shown.

[0099] In step A3, the travel section 26 is divided into a plurality of (N k ) trip partitions. It is known to those skilled in the art that this is a division for calibration. Depending on the trip and building conditions, the lengths of the trip partitions can be the same or different. After this division, the trip segment 26 has a first trip partition (k=1), a second trip partition (k=2), and generally the kth trip partition. In the following, the reference numeral k indicates for which trip partition the RSSI measurement value is determined.

[0100] The switched-on reference mobile radio device 2a is initially located at the start of the travel segment 26 and moves from there at a constant speed along the travel segment 26. If the reference mobile radio device 2a is in one of the travel segments (reference numeral k), then in step A4 a received signal strength indicator RSSI is determined and stored for each radio device 6 (reference numeral i). i，k , i.e. often with the following frequency (reference number j, number of measurements per travel segment) until the reference mobile radio device 2a reaches the end of the current travel segment. At the end of the current travel segment, the reference mobile radio device 2a sends a segment signal according to an embodiment. The signaling of the end of the travel segment ensures that the RSSI measurement values ​​can be correctly assigned, further processed and stored. If, for example, the received signal strength indicator N is determined for each radio device 6 (reference number i) and within the travel segment (reference number k) i，k times (with index j), the number of measured values ​​becomes {RSSI i，k，j}, the number is stored, for example, in the memory device 18. If the end of the path 26 has not yet been reached, the next travel segment follows and the described measuring process is repeated.

[0101] In step A5, the RSSI is formed from all measurements (reference numeral j) of the corresponding travel segment (reference numeral k) of each individual radio device 6 (reference numeral i). i，k The average value of the measured values. This average value is referred to as M(RSSI i，k ). This average value is determined based on the following formula:

[0102]

[0103] Where j = 1, ..., N j，k denoted by the jth measurement in the corresponding kth trip segment for the i-th radio device 6 .

[0104] In step A6, the mean value M(RSSI i，k ) to determine the loss coefficient α i，k The determination method is based on the following formula:

[0105]

[0106] Where j = 1, ..., N j，k = represents the jth measurement in the corresponding kth travel segment for the i-th radio device 6. At the known position of the radio device 6, the distance d from the mobile radio device 2a is thus obtained for each radio device 6. i，k，j (for tuple (i, k, j)).

[0107] In step A7 , the empirical covariance matrix Σ′ is determined over the entire travel segment 26 W The values ​​of the main diagonal of the matrix are are stored. These diagonal elements are measures of the different model error variances of the individual radio devices 6. Here, the empirical covariance matrix ∑′ W It involves the residual model error ε k，j :

[0108]

[0109]

[0110]

[0111]

[0112] In step A8, the average value M(RSSI i，k ), loss coefficient α i，k and covariance matrix ∑′ W This is then used for position determination in the application phase. The reference mobile radio device 2a and the selected radio device 6 can then be deactivated and the method ends in step S6.

[0113] In one embodiment of the technique presented here, the information obtained and stored in the calibration phase is used in the application phase to determine the current position P' of the user 4. Since the user 4 moves in the building, his movements can be tracked if the position determination is repeated at successive time intervals. The position P' determined in this way obtains the described trajectory (position path). The time interval can be selected as desired.

[0114] Figure 7 A flow chart of an embodiment of a method for operating an access monitoring system 1 is shown, wherein the position P' (or positions) of a user 4 is determined in an application phase. A user 4 carrying a mobile radio device 2 is located near a gate 14, wherein the Bluetooth function of the mobile radio device 2 is activated. Any relevant software applications are also activated. The user 4 moves from a public area 22 to a restricted access area 20, for example, along a travel section 26. It is assumed that the mobile radio device 2 is already within the radio range (RF1-RF4) of a radio device 6. In the embodiment presented here, the mobile radio device 2 sends a notice notification, referred to as an advertising event, as a radio signal, and all radio devices 6 within the radio range receive the radio signal. The method starts in step B1 and ends in step B12.

[0115] If the mobile radio device 2 communicates with one of the radio devices 6, the mobile radio device 2 also transmits a specific identifier. Figure 7 , the identifier is determined in step B10. The identifier can be a telephone number, a device address (media access control (MAC) address) or another identifier that uniquely identifies the mobile radio device 2. Since the mobile radio device 2 usually corresponds to the user 4 in a fixed manner, the identifier of the mobile radio device 2 also indirectly corresponds to the user 4. The access monitoring system 1 stores the identifier of the mobile radio device 2 corresponding to the user 4 authorized to access, for example in a storage device 18, wherein a user profile is created for each user 4. The name of the user 4 and his access authorization can be specified in the user profile, for example, which rooms 24 the user can access. It can also be specified on which day and at what time the access authorization exists. In one embodiment, the identified identifier is stored in the storage device 18. For example, in the storage device 18, a value that can be measured and / or calculated for the user 4 uniquely corresponds to the identifier.

[0116] In step B2, a received signal strength indicator RSSI is determined for each radio device 6. i In the embodiment described here, the received signal strength indicator RSSI i The determination is performed synchronously by the radio devices 6, i.e. the radio devices 6 have a common time reference (e.g. the same time), which allows simultaneous determination of the received signal strength indicator RSSIi ). The mobile radio device 2 is located at the current position, so that for the current position there are, for example, four received signal strength indicators RSSI i (i=1, 2, 3, 4). In each subsequent measurement, the four received signal strength indicators RSSI are measured again. i In one embodiment, the storage device 18 stores the received signal strength indicators RSSI. i .

[0117] In step B3, the current radio pattern ( Figure 2 This radio pattern (also called radio fingerprint) is determined by the radio device 6 in step B2 when the mobile radio device 2 is in a certain position. i That is, if the mobile radio device 2 is at a certain location, there are four received signal strength indicators RSSI i Represents the radio fingerprint of the location.

[0118] In step B4, the trip segment (k) is determined, in particular the trip segment (k) in which the user 4 is currently located. For this purpose, the current radio fingerprint determined in step B3 is used to search for an identical or at least very similar radio fingerprint in the storage device 18. Figure 6 As described in steps A4 and A5 of the present invention, each radio device 6 is assigned a received signal strength indicator RSSI measured for the determined trip segment (k). i，k，j The average value (M(RSSI i，k，j )), which average is stored in the storage device 18. If the current radio fingerprint (or its received signal strength indicator) is equal to the radio fingerprint (or its average received signal strength indicator (M(RSSI)) stored for the trip segment (k), i，k，j )) matches to a certain extent, then the itinerary segment (k) currently in which the user 4 is located is obtained. An exact match is not required, and the method searches for a stored radio fingerprint that is most similar to the current radio fingerprint.

[0119] In step B5, the loss coefficient α corresponding to the travel segment (k) determined in step B4 is read. i，k . Loss coefficient α i，k Stored in the storage device 18, such as in combination Figure 6 Thus, the reading is performed in the following manner, searching the storage device 18 through the determined travel partition segment (k) to find the loss coefficient α corresponding thereto. i，k . Loss coefficient α i，kSpecific to each trip segment (k) and specific to each radio device 6 .

[0120] In step B6, the weighting factor w is determined i The weighting factor w specifies the received signal strength indicator RSSI of the i-th radio device 6. i In one embodiment, only the strongest radio signals, i.e., those with the highest received signal strength indicator RSSI, are detected. i For example, the three (or four) highest received signal strength indicators RSSI can be selected i For these three (or four) radio signals, the weighting factor w i They are w i =1, and for other radio signals it is w i = 0. Generally, the weighting factor can be determined by the following equation:

[0121]

[0122] in,

[0123] In step B7, the user's current position P' is determined. The current position P' is a vector representing the xy position coordinates at a specific time point. The instantaneous position P' determined in this way may be the same as the actual position P of the user 4, but especially in actual situations inside a building, there may be a certain degree of deviation. It is determined according to the following formula:

[0124]

[0125] in:

[0126] N A : Number of radio devices 6

[0127] d′ i : the estimated distance between the mobile radio device 2 and the i-th radio device 6, and

[0128] P: optimization variable,

[0129] d i (p): Euclidean distance between p and the i-th radio device.

[0130] The corresponding distance d′ calculated based on the measured value i for:

[0131]

[0132] Among them, RSSI iis the current measurement value of the i-th radio device 6 .

[0133] The position P' corresponds to a snapshot of the user 4 as it moves along the travel segment 26. It is known to those skilled in the art that the movement of the user 4 can be tracked by repeatedly determining the position P'. This can be shown graphically, for example, as Figure 3 As shown in box 40.

[0134] In one embodiment, the position P' determined in step B7 may be further processed. This further processing may include time filtering, such as Figure 3 As shown in block 34 of FIG. 1 , the sensor values ​​are considered, such as Figure 3 32, or a combination of these. Figure 8 is shown in step B8.

[0135] According to an embodiment, because a large number of consecutive position determinations are performed, a temporal filtering can be performed. Therefore, a large number of positions P' are determined, which may include outliers, i.e. positions that deviate too much from neighboring values. Over time, the influence of these outliers can be reduced by filtering. In an embodiment, an average value is determined for five determined positions P'.

[0136] In one embodiment, a Kalman filter, in particular a so-called extended Kalman filter (EKF), may be used. Kalman filters and advanced Kalman filters are known to those skilled in the art, for example from I. Guvenc et al., "Enhancements to RSS Based Indoor Tracking Systems Using Kalman Filters", International Signal Processing Conference (ESPC) and Global Signal Processing Expo (GPSx), 2003. Kalman filters are typically used to reduce errors in actual measurements and to provide estimates for unmeasured system variables. A prerequisite for this is that the values ​​of interest can be described by a mathematical model, for example in the form of an equation of motion. The Kalman filter works by alternating prediction and measurement steps, requiring a state space vector x, a vector state update function f, and an observation space vector z or a vector measurement function h.

[0137] The state of a system is usually understood as the smallest set of determinants that fully describes the system. Within the scope of modeling, this is expressed in the form of a multidimensional vector x by the corresponding equation of motion f, the so-called state equation. This vector function f m Describes the continuous state (x m-1 and x m ). The process of observing the true system state reflects the characteristics of the observer or the measuring device. These are expressed by the so-called observation equations h m is associated with the expected state of the system according to the equations of motion. The corresponding modeling of the state and observation process is given below.

[0138] State space vector x m-1 , x m should be determined as accurately as possible. These relate to the continuous position P of the user 4, its absolute velocity (||v||) and its direction (θ) at the corresponding time point (m). If these are estimated, then a prediction (pred.) is made of how this state space vector will look at the next time step (e.g. from time point m-1 to time point m) (predicted state space vector ). Vector function f m (x m-1 ) is used for this purpose. In one embodiment, the vector function f m In each time step, φ is chosen such that it can be assumed that the user 4 moves with a constant speed and in the same direction.

[0139] In the next step, the predicted state space vector This will be improved by using the current measurement, which so far is based only on the last state and the transition function. Two different embodiments can be used for this purpose (the difference between the two embodiments is that the vector measurement function h m and the corresponding observation space vector or measurement vector z m ).

[0140] In a first embodiment (tri), the position determination (position P') from a previous position determination method is used as the measurement value. The predicted state space vector Correction is done by these position determination schemes.

[0141] thus:

[0142] z m，tri =P′ m ,

[0143]

[0144]

[0145] In a second embodiment, the vector measurement function h m，dir (which is based on the channel model) Calculate: If the user 4 is actually in the predicted state space vector When the conditions are defined, the RSSI value can be expected. Then, the expected RSSI value is directly ("dir" in the following formula) corrected by the measured RSSI value. Thus:

[0146]

[0147]

[0148]

[0149] In one embodiment, the method takes sensor values ​​into account when determining the position. In this embodiment, the mobile radio device 2 is an inertial measurement unit (IMU) (IMU measurement unit). If the mobile radio device 2 is designed as a so-called smartphone, it usually contains an IMU measurement unit. An IMU measurement unit is a spatial combination of multiple inertial sensors, such as accelerometers, magnetometers, pedometers and yaw rate sensors. For smartphones, the IMU measurement unit detects, for example, its inclination, position and / or rotation. This is known, for example, from the compass function of a smartphone or the function of rotating the screen display, which depends on how the user holds the smartphone 4.

[0150] The mobile radio device 2 determines, for example, the direction of movement of the user 4 and the acceleration obtained when the user 4 walks along the travel section 26 by means of the IMU measurement unit. The number of steps of the user 4 can be calculated from the acceleration values. In one embodiment, a known dead reckoning method is used to determine the movement speed of the user 4 based on the movement direction and the counted number of steps. Dead reckoning enables the current approximate position determination of a moving object based on the movement direction and speed. In one embodiment (the mobile radio device 2 sends an advertising event packet), the signal processing device 8 receives the measurement values ​​from the IMU measurement unit. After the measurement, the IMU data is transmitted to the signal processing device 8 together with the RSSI measurement value.

[0151] The measurement function of the filter combines the sensor data with the position and the received signal strength indicator RSSI by adding the movement speed and the IMU compass angle of the user 4 to the observation range. In this way, in particular, the movement of the user 4 over time can be better tracked. For example, if the user 4 changes the direction of movement, this can be recognized earlier, so that, for example, the gate 14 can be prevented from opening.

[0152] In step B9, a check is made as to whether the rules specified in the access monitoring system 1 are met. To check the rules, the identifier determined in step B10 is used to check whether a user profile exists for the user 4. If a user profile exists, the user 4 is known in the access monitoring system 1 and it can be checked whether he is authorized to access at this time. On the other hand, if the identifier is not stored in the access monitoring system 1, the user 4 has no access authorization.

[0153] Typically, for example, it can be determined that when the user 4 is authorized to access, the gate 14 is to be opened. If the gate is barrier-free, the rule can state that no measures (e.g., alarms) need to be taken. On the other hand, if the user 4 is not authorized to access, the rule can specify that the gate 14 remains blocked and / or security measures (e.g., notifying security personnel) are to be initiated. Depending on the building, the rule can also specify that the building action specified in its user profile is to be performed for the user 4 (who is authorized to access). For example, the building action can include triggering a target call for the user 4 (according to the data of the user profile that exists for the user 4), corresponding to which the elevator is assigned by the elevator control device 10, and the assigned elevator is displayed for the user 4 at the gate 14 or on the mobile radio device 2. In step B11, the building action is performed. It will be known to those skilled in the art that multiple building actions can also be performed in combination, such as opening the gate 14 and triggering an elevator call. The method ends in step B12.

[0154] In one embodiment, plausibility checks may be provided in the method. Such checks are intended to determine whether the determined position is fully plausible, i.e., to detect possible obvious inaccuracies. For example, an obvious inaccuracy may be that the determined position is outside the monitoring area or that two users are in the same position and are therefore allegedly standing in close proximity. In response to this, the determined position may be considered an outlier and rejected.

[0155] Figure 8 A flow chart of an additional embodiment of a method for operating an access monitoring system is shown, which starts in step C1 and ends in step C18. In this context, it can be seen in particular that after the calibration mode is selected in step C3, the method is divided into two method branches. The first method branch (steps C4-C8) determines the position of the user 4 according to an automated real-time calibration mode, and the second method branch (steps C10-C14) determines the position of the user 4 according to a calibration mode supported by a reference mobile radio device, which is operated based on calibration by a reference mobile radio device 2a during a calibration phase. The calibration mode supported by the reference mobile radio device is combined with Figure 6 and Figure 7 Make an introduction, Figure 7 Steps B3-B7 shown in FIG. 1 essentially correspond to Figure 8 The steps C10-C14 shown in FIG. 1 are therefore not described in detail at this point. This also applies to step C15 corresponding to step B10, step C10 corresponding to step C2, step C2 corresponding to step B2, and steps C9, C16 and C17 corresponding to steps B8, B9 and B11, respectively.

[0156] In the first method branch (steps C4-C8), the calibration mode is selected in step C3. This selection is similar to that in Figure 4 The selection disclosed in step T4 is performed based on at least one situation indicator indicating the radio situation in the monitoring area.

[0157] If the automatic real-time calibration mode is selected, the received signal strength indicator RSSI associated with the user 4 determined in step C2 is stored in step C4. i For example, the data is stored in the storage device 18 .

[0158] In step C5, all RSSI values ​​stored for user 4 in step C4 are combined. i To form a signal strength vector.

[0159] In step C6, the reference received signal strength indicator is read from the storage device 18 The average value determined during the calibration phase.

[0160] In step C8, the location of user 4 is determined. The received signal strength RSSI determined in step C2 and steps C4-C6 i Indicators, benchmark received signal strength indicators The average value of and the known position of the radio device 6, the position P' can be determined by the consumption optimization function. i The maximum likelihood estimation is determined based on the previous possible position paths. Maximum likelihood estimation is known to those skilled in the art and refers to parameter estimation methods in statistics. In short, the parameter is selected as an estimate that, according to its distribution, achieves the most reasonable value of the likelihood of the observed data. According to the negative log-likelihood function, the loss coefficient α determined is i The resulting remaining consumption is determined by considering it as a function of the position path. The remaining consumption on the possible position paths is then minimized. The minimization can be performed by a minimization algorithm known to those skilled in the art, for example by the known Levenberg-Marquardt algorithm. For example, the consumption optimization function can be performed using the software product MATLAB from The MathWorks, Inc., USA. The latest component of the position path found in this way is then used as the determined current position P'.

[0161] When the position of the user 4 is determined in this way, the method can proceed to the further steps C9, C16 and C17. The method ends at step C18.

[0162] In one embodiment, the signal processing device 8 is designed to apply the techniques described herein in combination with one or more machine learning algorithms (also referred to as machine learning) in order to automatically further improve the accuracy of position determination or position tracking. The computer program installed in the signal processing device 8 is programmed to execute the corresponding algorithm or algorithms. The machine learning algorithm usually consists of a training phase and an application phase. When executed in the application phase, the computer program accesses one or more data sets stored in the storage device 18 during the training phase. Such data sets involve data about the position determination that has occurred (e.g., status indicators, received signal strength indicators RSSI i ), for example, also includes whether the position determination or position tracking is successful. Whether the position tracking is successful can be verified later, for example, whether the user 4 entering from door A actually passed through door B. In the application phase, the currently determined data (radio status, current received signal strength indicator RSSI) related to the data determined in the training phase are analyzed by a computer program. i ) to determine a function that reflects the current position or its trajectory with the help of the currently determined data.

[0163] The mobile radio device 2 can be, for example, an application-specific software application (also referred to as an application) that can be activated by the user 4. In one embodiment, the dedicated software application is used in conjunction with access monitoring and the use of the elevator. In one embodiment, the dedicated software controls the generation and transmission of the radio signal. Depending on the design, the software can also generate an identifier for the mobile radio device 2, for example an identifier that is unique to the mobile radio device 2 and cannot change over time. Such an identifier generated by the software is an alternative to a device identification number and a telephone number that can also be used as an identifier.

[0164] The mobile radio device 2 can be, for example, a mobile phone, a smartphone or a tablet PC, which are usually equipped with hardware capable of radio communication. However, the mobile radio device 2 can also be a pair of glasses with a microcomputer or another computer-assisted device worn on the body (also called a "wearable device"), in particular a smart watch. Depending on the design of the mobile radio device 2, the mobile radio device can operate the mobile radio device 2, for example, via a graphical user interface (also called a graphical user interface, GUI) and can selectively activate and deactivate its functions.

[0165] In summary, one aspect of the technology described herein relates to a system for monitoring access to a restricted access area in a building, and another aspect relates to a method for monitoring access to a restricted access area in a building. Other aspects of the technology described herein relate to systems and methods for determining the location of a user or its temporal distribution, for example in combination with Figure 4 and Figure 7 The determination of the position or its temporal distribution can be performed and claimed independently of access monitoring to access-restricted areas in a building. Additional aspects of the technology presented here relate to systems and methods for calibrating parameters for position determination, for example in combination with Figure 5 and Figure 6 The calibration may be implemented and claimed independently of access monitoring and independently of the determination of the position or its distribution over time. In addition, one aspect of the technology presented herein relates to a system in which one or more algorithms for machine learning are used to automatically further improve the accuracy of the position determination or position tracking.

Claims

1. A system (1) for monitoring access to a restricted access area (20) in a building, wherein: The gate (14) separates the restricted access area (20) from the public area (22), and the system comprises: A radio device (6) is arranged at a determined position at a determined distance from the gate (14) and defines a monitoring area. The radio device (6) is designed to perform radio communication with a mobile radio device (2) that is within the radio range and assigned to a user (4). The mobile radio device (2) is a smartphone, a tablet computer, or a wearable electronic device. The first mobile radio device at the position P of the first user (4) is at a distance d from each of the radio devices (6). i ; A control device (10, 12) connected to the building equipment (16) in a communicative manner; a data storage device (18) having stored therein processing instructions for a situation-specific calibration mode and a unique identifier of the first mobile radio device, wherein the unique identifier is sent by the first mobile radio device; and A signal processing device (8) is communicatively connected to a data storage device (18), a radio device (6) and a control device (10, 12), wherein the signal processing device (8) is designed to: evaluating radio communications within the surveillance area and determining therefrom at least one condition indicator indicative of radio conditions existing in the surveillance area; For each radio device (6), a received signal strength indicator RSSI is detected based on radio communication with the first mobile radio device. i ; selecting a calibration mode corresponding to at least one condition indicator and reading processing instructions corresponding to the selected calibration mode from a data storage device (18); According to the read processing instruction, the current position P' of the first mobile radio device is determined as the detected received signal strength indicator RSSI i functions of ; and When a certain rule is met based on the identifier of the mobile radio device (2) and the determined current position P', a control signal is fed to the control device, wherein the control device is designed to trigger a building action corresponding to the certain rule.

2. The system (1) according to claim 1, wherein: The building action is to open the gate (14).

3. The system (1) according to claim 1, wherein: The at least one status indicator represents the type of mobile radio device, the number of mobile radio devices (2) in the monitoring area, the spatial orientation of the mobile radio device (2), the entry position of the user (4) into the monitoring area, sensor data generated by the mobile radio device (2), the time, the number of radio devices (6), the available computing power, the density of the radio devices (6) or the size of the room.

4. The system (1) according to any one of claims 1 to 3, wherein: Also stored in the data storage device (18) are: Radio signal strength reference value M (RSSI d0 ), in a calibration phase, the radio signal strength reference value is determined based on radio communication between one of the radio devices (6) and a reference mobile radio device (2a) arranged at a reference distance d0 therefrom, a reference radio signal pattern FP as a function of the position of the reference mobile radio device (2a), wherein the reference radio signal pattern FP is determined in a calibration phase based on radio communication between the radio device (6) and the reference mobile radio device (2a), and The loss coefficient α determined for each radio device during the calibration phase as a function of the reference position of the reference mobile radio device (2a), wherein the loss coefficient determined for the i-th radio device is denoted as loss coefficient α i .

5. The system (1) according to claim 4, wherein: The first processing instruction for the first calibration mode determines the position according to the following equation: Among them, N A represents the number of radio devices (6) and d i (p) represents the Euclidean distance between the i-th radio device (6) and the variable position p of the user (4), w i represents a weighting factor, the weighting factor being based on the received signal strength indicator RSSI of the i-th radio device (6) i The influence of the measurement of on the position determination, the distance d′ between the mobile radio device (2) and the i-th radio device (6) determined by means of the reference radio signal pattern FP i According to the following formula:

6. The system (1) according to claim 5, wherein: The loss coefficient α of the i-th radio device in the k-th travel section of the determined travel section i，k Determined according to the following formula: Where j = 1, ..., N j，k represents the jth measurement for the i-th radio device (6) in the k-th trip partition of a determined trip segment, the trip partition being determined in the calibration phase, d i，k，j represents the jth measured distance from the mobile radio device in the kth travel segment of the determined travel segment for the i-th radio device (6), RSSI i,k，j The received signal strength indicator is represented by the jth measurement of the i-th radio device (6) in the k-th travel sub-segment of the determined travel segment.

7. The system (1) according to claim 4, wherein: The second processing instruction for the second calibration mode determines to obtain the trajectory of the movement of the user (4), the acquisition is based on the determined position of the radio device (6), the detected received signal strength indicator RSSI i and radio signal strength baseline Loss coefficient α i The residual consumption is determined by means of maximum likelihood estimation, and the loss coefficient α is determined by introducing i The case is determined according to the negative log-likelihood function, and the remaining consumption on the location path is minimized.

8. The system (1) according to any one of claims 1 to 3, wherein: The radio device (6) and the mobile radio device (2) are designed for radio communication according to Bluetooth technology.

9. A method for operating a system (1) for monitoring access to a restricted access area (20) in a building, wherein: The gate (14) separates the restricted access area (20) from the public area (22), and the system (1) comprises: A radio device (6) is arranged at a determined position at a determined distance from the gate (14) and defines a monitoring area. The radio device (6) is designed to perform radio communication with a mobile radio device (2) that is within the radio range and assigned to a user (4). The mobile radio device (2) is a smartphone, a tablet computer, or a wearable electronic device. A first mobile radio device at a first position P of a first user (4) is at a distance d from each of the radio devices (6). i ; A control device (10, 12) connected to the building equipment (16) in a communicative manner; a data storage device (18) in which are stored processing instructions for a situation-specific calibration mode and a unique identifier of the first mobile radio device, wherein the unique identifier is transmitted by the first mobile radio device during radio communication with the radio device (6); and A signal processing device (8) is communicatively connected to a data storage device (18), a radio device (6) and a control device (10, 12), wherein the method comprises: evaluating radio communications within a monitoring area and determining, based on the evaluation, a condition indicator indicative of radio conditions existing within the monitoring area; Based on the radio communication with the first mobile radio device, a received signal strength indicator RSSI is detected for each radio device (6). i ; selecting a calibration mode corresponding to the condition indicator and reading a processing instruction corresponding to the calibration mode from the data storage device (18); According to the read processing instruction, the current position P' of the first mobile radio device is determined as the detected received signal strength indicator RSSI i functions of ; and If a certain rule is met based on the identifier of the mobile radio device (2) and the determined current position P', a control signal for a control device is generated by the signal processing device (8) and a building action corresponding to the determined rule is triggered by the control device.

10. The method according to claim 9, wherein: The building action is to open the gate (14).

11. The method according to claim 9, wherein: The situation indicator represents the type of mobile radio device, the number of mobile radio devices (2) in the monitoring area, the spatial orientation of the mobile radio device (2), the entry position of the user (4) into the monitoring area, sensor data generated by the mobile radio device (2), the time, the number of radio devices (6), the available computing power, the density of the radio devices (6) or the size of the room.

12. The method according to any one of claims 9 to 11, wherein: Also stored in the data storage device (18) are: Radio signal strength reference value M (RSSI d0 ), wherein the radio signal strength reference value is determined based on radio communication between one of the radio devices (6) and a reference mobile radio device (2a) arranged at a reference distance d0 therefrom, a reference radio signal pattern FP as a function of the position of the reference mobile radio device (2a), wherein the reference radio signal pattern FP is determined based on radio communication between the radio device (6) and the reference mobile radio device (2a), and The loss coefficient α determined for each radio device during the calibration phase as a function of the reference position of the reference mobile radio device (2a), wherein the loss coefficient determined for the i-th radio device is denoted as loss coefficient α i .

13. The method according to claim 12, wherein: According to the first processing instruction for the first calibration mode, the position determination is performed according to the following formula: Among them, N A represents the number of radio devices (6), and d i (p) represents the Euclidean distance between the i-th radio device (6) and the variable position p of the user (4), w i represents a weighting factor, the weighting factor being based on the received signal strength indicator RSSI of the i-th radio device (6) i The influence of the measurement of on the position determination, the distance d′ between the mobile radio device (2) and the i-th radio device (6) determined by means of the reference radio signal pattern FP i According to the following formula:

14. The method according to claim 12, wherein: The loss coefficient α of the i-th radio device in the k-th travel section of the determined travel section i，k Determined according to the following formula: Where j = 1, ..., N j，k represents the jth measurement for the i-th radio device (6) in the k-th trip partition of a determined trip segment, the trip partition being determined in the calibration phase, d i，k，j represents the jth measured distance from the mobile radio device in the kth travel segment of the determined travel segment for the i-th radio device (6), RSSI i，k，j The received signal strength indicator is represented by the jth measurement of the i-th radio device (6) in the k-th travel sub-segment of the determined travel segment.

15. The method according to claim 12, wherein: The second processing instruction for the second calibration mode determines to obtain the trajectory of the movement of the user (4), the acquisition is based on the determined position of the radio device (6), the detected received signal strength indicator RSSI i and radio signal strength baseline Loss coefficient α i The residual consumption is determined by means of maximum likelihood estimation, and the loss coefficient α is determined by introducing i The case is determined according to the negative log-likelihood function, and the remaining consumption on the location path is minimized.

Images