JP6245658B2 - Position estimation system, position estimation method, program - Google Patents

Description

  The present invention relates to a position estimation system, a position estimation method, and a program for estimating the position of a terminal device existing in a predetermined space.

  In recent years, the O2O (Online to Offline) market in which various functions of the Internet are utilized to attract customers from online (online) to actual stores (offline) and sell goods is expanding. In the O2O market, for example, services linked with location information in actual stores are rapidly spreading, and interest in location measurement technology is increasing.

  Many position information services use GPS (Global Positioning System) as a position measurement technique. However, since it is difficult to receive GPS radio waves in an indoor environment, it has been difficult to suitably use GPS in an indoor location information service such as in an actual store. Thus, a pedestrian dead reckoning (PDR) technique for measuring the position of the user indoors using a sensor provided in a terminal device possessed by the user has been proposed.

  As such a PDR technique, for example, by using a terminal device including an acceleration sensor and a direction sensor such as a geomagnetic sensor, it is estimated by what speed the user is moving in which direction, What measures the position (namely, user's position) of the said terminal device is known (for example, refer to patent documents 1).

JP 2000-097722 A

  By the way, when estimating the moving direction of a terminal device using a direction sensor, the possession mode of the terminal device (for example, the user is operating the terminal device while walking, the user shakes the hand holding the terminal device). Depending on the movement direction of the terminal device (that is, the movement direction of the user) and the direction in which the terminal device faces, depending on whether the user is walking or the user is walking with the terminal device in a bag or the like. Since they do not always match, there are cases where the moving direction of the terminal device cannot be accurately estimated.

  As described above, when the direction sensor is used, the moving direction of the terminal device may not be accurately estimated. As a result, for example, the position of the terminal device existing in a space such as indoors (that is, It may be difficult to accurately estimate the user's position.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a position estimation system, a position estimation method, and a program capable of accurately estimating the position of a terminal device existing in a predetermined space. To do.

  In order to solve the above problems, first, the present invention is a position estimation system for estimating the position of a terminal device existing in a predetermined space, and is transmitted from a plurality of communication devices provided in the space. Acquisition of information on received signal strength when the terminal device receives received radio waves, or information on received signal strength when the plurality of communication devices receive radio waves transmitted from the terminal devices over time And the position of the terminal device at the first timing based on the information on the received signal strength obtained at the first timing and the information on the received signal strength obtained at the second timing after the first timing. Based on a combined vector obtained by synthesizing the displacement vector for each of the plurality of communication devices, generating means for generating a displacement vector for each of the plurality of communication devices, There is provided a position estimation system comprising: direction estimation means for estimating the movement direction of the terminal apparatus; and position estimation means for estimating the position of the terminal apparatus at the second timing based on the estimated movement direction ( Invention 1).

  Here, the information regarding the received signal strength may be, for example, a value (RSSI value) of the received signal strength, or a value obtained by substituting the RSSI value into a predetermined calculation formula. Alternatively, it may be information indicating the degree of received signal strength.

  According to this invention (Invention 1), based on the information on the received signal strength of the radio wave received by the terminal device or the plurality of communication devices, a displacement vector corresponding to each of the plurality of communication devices is generated, and these displacement vectors Since the moving direction of the terminal device is estimated based on the combined vector generated based on the terminal device, the moving direction of the terminal device can be estimated based on the received signal strength of the radio wave received by the terminal device or the plurality of communication devices. It becomes possible. Here, when estimating the moving direction of the terminal device using the received signal strength, the received signal strength is the same regardless of whether the moving direction of the terminal device matches the direction in which the terminal device faces, for example. Therefore, compared with the case where the moving direction of the terminal device is estimated using a direction sensor such as a gyro sensor or a geomagnetic sensor, the influence of the terminal device possessing mode can be suppressed. For this reason, the moving direction of a terminal device can be estimated correctly. Moreover, in this invention (invention 1), since the position of the terminal device is estimated based on the movement direction thus estimated, the position of the terminal device existing in a predetermined space (that is, the position of the user). Can be estimated accurately.

  In the above invention (Invention 1), the displacement vector represents a displacement of a distance between any one of the plurality of communication devices and the terminal device from the first timing to the second timing, The direction estimation unit estimates a movement direction and a movement distance of the terminal device based on the combined vector, and the position estimation unit calculates the position at the second timing based on the estimated movement direction and movement distance. It is preferable to estimate the position of the terminal device (Invention 2).

  According to the invention (Invention 2), the terminal device has a synthesized vector obtained by synthesizing a displacement vector representing a displacement from the first timing to the second timing of the distance between each of the plurality of communication devices and the terminal device. Since it is possible to represent not only the moving direction but also the moving distance of the terminal device from the first timing to the second timing, the end point of this combined vector can be estimated as the position of the terminal device at the second timing. As a result, the position of the terminal device can be estimated without using a device for measuring the moving distance such as an acceleration sensor, for example, so that the position of the terminal device can be easily estimated and the position estimation system can be manufactured. Cost can be reduced.

  In the above invention (Invention 2), when the information about the received signal strength is acquired, a correction unit that corrects the received signal strength based on a difference between the received signal strength and a predetermined reference value of the received signal strength is provided, The generating means is based on the received signal strength acquired at the first timing and corrected, and the received signal strength acquired at the second timing and corrected received signal strength information. The displacement vector is preferably generated for each of the plurality of communication devices (invention 3).

  The relationship between the distance between the terminal device and the communication device and the received signal strength may be different for each type and / or individual of the terminal device or the communication device, and may be different depending on the environment around the terminal device or the communication device. For example, when estimating the position of the second terminal device different from the first terminal device using the relationship between the distance between the first terminal device and the communication device and the received signal strength, the second terminal Even if the device exists at the same position as the first terminal device, the distance between the second terminal device and the communication device determined based on the above relationship is different from the distance between the first terminal device and the communication device. There is a case. In this case, since it can be estimated that the second terminal device is located at a different position from the first terminal device, there is a possibility that the position of the terminal device cannot be estimated accurately.

  According to this invention (Invention 3), when information on the received signal strength is acquired, the received signal strength is corrected based on the difference between the received signal strength and a predetermined reference value of the received signal strength. Even when a different terminal device or communication device is used or when the environment around the terminal device or communication device is different, the received signal strength is corrected so as to conform to the predetermined relationship between the distance and the received signal strength. Thus, the difference in the relationship between the distance and the received signal based on the difference in the type or environment of the terminal device or communication device can be reduced, and consequently the position of the terminal device can be accurately estimated. Therefore, the position of the terminal device can be accurately estimated regardless of the type and / or individual of the terminal device or communication device and the environment around the terminal device or communication device.

  In the above inventions (Inventions 1 to 3), the position estimation means is configured such that when the received signal strength corresponding to at least one communication device among the plurality of communication devices is equal to or greater than a predetermined threshold at the second timing, It is preferable to estimate the position of the terminal device at the second timing to a predetermined position (Invention 4).

  For example, in the case where an error occurs between the accurate position of the terminal device and the estimated position every time the position of the terminal device is estimated, the terminal device is accumulated in an error every time the position of the terminal device is repeatedly estimated. Therefore, it may be difficult to accurately estimate the position of the terminal device. By the way, the received signal strength of radio waves transmitted and received between the terminal device and the communication device increases as these distances become shorter, and decreases as these distances become longer. It is possible to estimate the distance to the communication device.

  According to this invention (invention 4), for example, when the received signal strength at the second timing is equal to or higher than a predetermined threshold, the position of the terminal device at the second timing is set to a predetermined position (for example, received signal strength equal to or higher than the threshold). Therefore, the position of the terminal device can be accurately estimated based on the relationship between the distance between the terminal device and the communication device and the received signal strength. Thereby, for example, even when an error occurs between the accurate position of the terminal device and the estimated position, it is possible to suppress a new estimation of the position of the terminal device in a state where this error is accumulated. Can do.

  In the above inventions (Inventions 1 to 4), the generation means includes an average value of received signal strengths corresponding to each of the plurality of communication devices in a first period before the first timing, and the plurality of communication devices. Preferably, the displacement vector is generated for each of the plurality of communication devices based on the average value of the received signal strength corresponding to each of the first and second values within the second period before the second timing (invention 5).

  For example, when the received signal strength acquired at least one of the first timing and the second timing is an abnormal value, the received signal strength is used as it is for estimation of the moving direction, thereby degrading the estimation accuracy of the moving direction, and consequently There is a possibility that the estimation accuracy of the position of the terminal device may deteriorate. According to this invention (invention 5), since the position of the terminal device can be estimated based on the average value of the received signal strength corresponding to each of the plurality of communication devices, for example, the abnormal value of the received signal strength is the first value. Even when included in at least one of the period and the second period, the influence of the abnormal value can be reduced by averaging the received signal intensity in each period. As a result, it is possible to suppress the deterioration of the estimation accuracy of the moving direction based on the abnormal value of the received signal strength, and thereby suppress the deterioration of the estimation accuracy of the position of the terminal device 20.

  In the said invention (invention 1-5), it is preferable that three or more of the said communication apparatuses are provided in the said space (invention 6).

  According to this invention (invention 6), each of the three or more displacement vectors starting from the position of the terminal device at the first timing is generated so as to face in any direction along the same plane. Therefore, the combined vector of each displacement vector can also be generated so as to face in any direction along the plane. Thereby, the moving direction of a terminal device can be estimated two-dimensionally.

  Second, the present invention is a position estimation method for causing a computer to estimate the position of a terminal device existing in a predetermined space, wherein the computer transmits radio waves transmitted from a plurality of communication devices provided in the space. Obtaining information regarding received signal strength when the terminal device has received, or information regarding received signal strength when the plurality of communication devices receive radio waves transmitted from the terminal device, over time; Based on the information on the received signal strength acquired at the first timing and the information on the received signal strength acquired at the second timing after the first timing, the displacement starting from the position of the terminal device at the first timing Generating a vector for each of the plurality of communication devices, and based on a combined vector obtained by combining displacement vectors for the plurality of communication devices. Providing a position estimation method for executing each step of estimating the moving direction of the terminal device and estimating the position of the terminal device at the second timing based on the estimated moving direction. (Invention 7)

  Thirdly, the present invention is a program for causing a computer to estimate the position of a terminal device existing in a predetermined space, wherein the computer transmits radio waves transmitted from a plurality of communication devices provided in the space. A function of acquiring information on received signal strength when received by the terminal device or information on received signal strength when the plurality of communication devices receive radio waves transmitted from the terminal device over time, first timing The displacement vector starting from the position of the terminal device at the first timing is based on the information on the received signal strength acquired at step 2 and the information about the received signal strength acquired at the second timing after the first timing. Based on a function that is generated for each of a plurality of communication devices, and a combined vector obtained by combining displacement vectors for each of the plurality of communication devices, the terminal Function of estimating the moving direction of the location, and based on the moving direction estimated to provide a program for realizing the function, estimating the position of the terminal device in the second timing (invention 8).

  According to the position estimation system, the position estimation method, and the program of the present invention, it is possible to accurately estimate the position of a terminal device existing in a predetermined space. For this reason, for example, it can be suitably used for an indoor location information service such as in an actual store.

It is a figure which shows schematically the basic composition of the position estimation system which concerns on one Embodiment of this invention. It is a block diagram which shows the structure of a terminal device. It is a functional block diagram for demonstrating the function which plays a main role in a position estimation system. It is a figure which shows an example of the moving direction of the terminal device in space. It is a figure which shows the structural example of displacement data. It is a figure which shows an example of the displacement vector corresponding to each of a some communication apparatus. It is a figure which shows an example of a synthetic | combination vector. It is a figure which shows an example of the estimated position of a terminal device. It is a flowchart which shows an example of the main processes of the position estimation system which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the displacement data in a modification. It is a figure which shows an example of the moving direction of the terminal device in the position estimation system which concerns on a modification. It is a figure which shows the relationship between the distance between a communication apparatus and a terminal device, and received signal strength. It is a figure which shows the structural example of the displacement data in a modification. It is a functional block diagram for demonstrating the function which plays a main role in the position estimation system which concerns on a modification. It is a figure explaining the correction value of received signal strength.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, this embodiment is an exemplification, and the present invention is not limited to this.

(1) Basic Configuration of Position Estimation System FIG. 1 is a diagram schematically showing a basic configuration of a position estimation system according to an embodiment of the present invention. As shown in FIG. 1, in this position estimation system, for example, the terminal device 20 receives radio waves transmitted from a plurality of (three in FIG. 1) communication devices 10 provided in a predetermined space S in the actual store. The terminal device 20 estimates its own moving direction based on the received signal strength (RSSI) at the time, and estimates its own position based on the estimated moving direction.

  Each communication device 10 is provided in a space S at a position where wireless communication with the terminal device 20 can be performed using Bluetooth (registered trademark), and is configured to transmit radio waves for wireless communication. Yes. In the example of FIG. 1, a case where each communication device 10 is provided at the same height is shown as an example, but each communication device 10 may be provided at a different height. In addition, here, a case where wireless communication is performed using Bluetooth (registered trademark) is described as an example, but the present invention is not limited to this case. For example, a wireless communication method such as a wireless LAN (for example, Wi-Fi (registered trademark)), ZigBee (registered trademark), UWB, optical wireless communication (for example, infrared) may be used. Furthermore, each communication device 10 may be configured to receive radio waves transmitted from the terminal device 20 in order to directly receive data from the terminal device 20. In addition, each communication device 10 may relay wireless communication between the terminal device 20 and another terminal device (not shown) existing in the radio wave reachable range, or the terminal device 20 and the communication device 10. Relaying communication with another communication device (for example, a service providing server for providing a service based on the position in the space S of the terminal device 20) connected to the device in a wired or wireless manner Good.

  When the terminal device 20 exists in the space S, the terminal device 20 can perform wireless communication with each communication device 10, and a received signal when a radio wave transmitted from each communication device 10 is received. It is configured to be able to measure the intensity. The terminal device 20 is, for example, a mobile terminal, a smartphone, a PDA (Personal Digital Assistant), a personal computer, a television receiver having a bidirectional communication function (including a so-called multifunctional smart TV), and the like. It may be a communication terminal operated by an individual user.

(2) Configuration of Terminal Device The terminal device 20 will be described with reference to FIG. FIG. 2 is a block diagram showing an internal configuration of the terminal device 20. As illustrated in FIG. 2, the terminal device 20 includes a CPU (Central Processing Unit) 21, a ROM (Read Only Memory) 22, a RAM (Random Access Memory) 23, a nonvolatile memory 24, a display processing unit 25, and the like. The display unit 26, the input unit 27, the acceleration sensor 28, and the communication interface unit 29 are provided, and a bus 20a is provided for transmitting control signals or data signals between the units.

  When the power is turned on to the terminal device 20, the CPU 21 loads various programs stored in the ROM 22 or the nonvolatile memory 24 to the RAM 23 and executes them. In the present embodiment, the CPU 21 reads and executes a program stored in the ROM 22 or the nonvolatile memory 24, thereby obtaining an acquisition unit 41, a generation unit 42, a direction estimation unit 43, and a position estimation unit 44 (described in FIG. 3). To achieve the functions shown). The CPU 21 receives a signal transmitted from each communication device 10 via the communication interface unit 29 and interprets the signal. Further, the CPU 21 may transmit data stored in the ROM 22, RAM 23, or nonvolatile memory 24 to each communication device 10 via the communication interface unit 29.

  The nonvolatile memory 24 is, for example, a flash memory, and stores a program executed by the CPU 21 and data referred to by the CPU 21. The nonvolatile memory 24 may store displacement data (shown in FIG. 5) described later.

  The display processing unit 25 displays the display data given from the CPU 21 on the display unit 26. The display unit 26 is, for example, an LCD (Liquid Cristal Display) monitor including thin film transistors arranged in units of pixels in a matrix, and drives the thin film transistors based on the display data to display the displayed data on the display screen. indicate.

  When the terminal device 20 is a button input type communication terminal, the input unit 27 includes a button group including a plurality of instruction input buttons such as a direction instruction button and a determination button for accepting a user operation input, a numeric keypad, and the like. A button group including a plurality of instruction input buttons, and includes an interface circuit for recognizing a pressing (operation) input of each button and outputting it to the CPU 21.

  When the terminal device 20 is a touch panel input type communication terminal, the input unit 27 receives a touch panel type input mainly by touching the display screen with a fingertip or a pen. The touch panel input method may be a known method such as a capacitance method.

  The acceleration sensor 28 is, for example, a triaxial acceleration sensor, and is a sensor that outputs a predetermined detection signal at a constant period in accordance with the triaxial acceleration of the terminal device 20. For example, the acceleration sensor 28 outputs a positive signal when the acceleration of the terminal device 20 is increasing, and outputs a negative signal when deceleration is occurring.

  The communication interface unit 29 includes an interface circuit for performing communication using the above-described wireless communication method and an interface circuit for performing communication via the communication network NW. An interface circuit for performing communication using a wireless communication system is provided with an RSSI circuit that detects a received signal strength value (RSSI value) when a radio wave transmitted from each communication device 10 is received. Here, the CPU 21 stores the detected RSSI value in the RAM 23 or the nonvolatile memory 24 in association with, for example, the identification information of the communication device 10 that has transmitted the radio wave. Here, the identification information of the communication device 10 may be acquired from the communication device 10 when the terminal device 20 receives a radio wave from the communication device 10, for example.

(3) Overview of Functions in Position Estimation System Functions realized by the position estimation system of the present embodiment will be described with reference to FIG. FIG. 3 is a functional block diagram for explaining functions that play a major role in the position estimation system of the present embodiment. In the functional block diagram of FIG. 3, the acquisition unit 41, the generation unit 42, the direction estimation unit 43, and the position estimation unit 44 correspond to the main configuration of the present invention.

  In describing each function in the position estimation system of the present embodiment, it is assumed that each communication device 10 transmits radio waves constantly or at predetermined intervals (for example, intervals of several tens to several hundred milliseconds). Further, as shown in FIG. 4, the terminal device 20 exists on the xy plane when the plane in the space S extending in the horizontal direction perpendicular to the gravitational direction is the xy plane. , It is assumed that radio waves transmitted from each communication device 10 are sequentially received.

  Here, it is preferable that three or more communication devices 10 are provided in the space S. In this case, as described later, each of the displacement vectors DV1, DV2, DV3, DV4 (shown in FIG. 6) starting from the position of the terminal device 20 at the first timing is set in any direction along the xy plane. Therefore, the combined vector RV (shown in FIG. 7) of the displacement vectors DV1, DV2, DV3, DV4 can also be generated so as to face any direction along the xy plane. . Thereby, the moving direction of the terminal device 20 can be estimated two-dimensionally.

  In the following description, a case where four communication devices 10 are provided in the space S (the four corners in the x-axis direction and the y-axis direction of the xy plane) will be described as an example. In addition, each of the four communication devices 10 is appropriately described as communication device A, communication device B, communication device C, and communication device D.

  The acquisition unit 41 includes information on received signal strength when the terminal device 20 receives radio waves transmitted from the plurality of communication devices 10 provided in the space S, or a plurality of radio waves transmitted from the terminal device 20. The communication apparatus 10 has a function of acquiring information related to received signal strength over time. Here, a case will be described as an example in which the acquisition unit 41 acquires information on the received signal strength over time when the terminal device 20 receives radio waves transmitted from the plurality of communication devices 10.

  The information on the received signal strength may be, for example, a received signal strength value (RSSI value) or a value obtained by substituting the RSSI value into a predetermined calculation formula. Information indicating the degree of received signal strength may be used.

  The function of the acquisition means 41 is implement | achieved as follows, for example. Each time the CPU 21 of the terminal device 20 receives a radio wave transmitted from each communication device 10, the CPU 21 associates the RSSI value detected by the communication interface unit 29 with the identification information of the communication device 10 that has transmitted the radio wave. For example, it is stored in the RAM 23.

  The generation unit 42 starts the position of the terminal device 20 at the first timing based on the information about the received signal strength acquired at the first timing and the information about the received signal strength acquired at the second timing after the first timing. Is provided for each of the plurality of communication devices 10.

  The function of the production | generation means 42 is implement | achieved as follows, for example. Here, a case where the terminal device 20 exists at the position P (shown in FIG. 6) on the xy plane in the space S at the first timing will be described as an example. When the CPU 21 of the terminal device 20 stores the RSSI value of the radio wave received from each of the plurality of communication devices A, B, C, and D at the first timing based on the function of the acquisition unit 41, the CPU 21 stores the RSSI value. For example, the RSSI value is stored in the displacement data shown in FIG. The displacement data includes an RSSI value at the first timing, an RSSI value at the second timing after the first timing, and a displacement of the RSSI value between the first timing and the second timing. , C, and D. The displacement data is stored in the nonvolatile memory 24 of the terminal device 20, for example.

  Next, the CPU 21 of the terminal device 20 has a plurality of communication devices A, B, C, and D at the second timing after the first timing (for example, 1 second after the first timing) based on the function of the acquisition unit 41. When the RSSI value of the radio wave received from each is acquired and stored in the RAM 23, the RSSI value stored in the RAM 23 is used as the received signal strength for each of the plurality of communication devices A, B, C, and D at the second timing. To remember. Then, the CPU 21 calculates the displacement of the RSSI value between the first timing and the second timing for each of the plurality of communication devices A, B, C, and D, and stores the calculated displacement value in the displacement data.

  Then, the CPU 21 of the terminal device 20 generates a displacement vector starting from the position P of the terminal device 20 at the first timing for each of the plurality of communication devices A, B, C, and D on the xy plane. Specifically, first, the CPU 21 accesses the displacement data and extracts the displacement values of the communication devices A, B, C, and D. Next, for example, as shown in FIG. 6, the CPU 21 converts the displacement vectors DV1, DV2, DV3, DV4 starting from the position P into the communication devices A, B, C, D and the position P on the xy plane. Generate on a straight line connecting Here, the displacement vector DV1 corresponds to the communication device A, the displacement vector DV2 corresponds to the communication device B, the displacement vector DV3 corresponds to the communication device C, and the displacement vector DV4 corresponds to the communication device D. It corresponds. The magnitude of each displacement vector DV1, DV2, DV3, DV4 corresponds to the absolute value of the displacement value of the corresponding communication device 10. Also, the direction of each displacement vector DV1, DV2, DV3, DV4 is a direction toward the corresponding communication device 10 when the displacement value of the corresponding communication device 10 is positive, and the displacement value of the corresponding communication device 10 is In the negative case, the direction is away from the corresponding communication device 10.

  Note that when the CPU 21 estimates the position of the terminal device 20 at the second timing based on the function of the position estimation unit 44 described later, the CPU 21 accesses the displacement data and the plurality of communication devices A, B, C, The received signal strength for each D is stored as the received signal strength for each of the plurality of communication devices A, B, C, and D at the first timing. Then, when the CPU 21 newly acquires the RSSI value of the radio wave received from each of the plurality of communication devices A, B, C, and D from the terminal device 20, the acquired RSSI value is obtained from the plurality of communication devices A at the second timing. , B, C, and D are stored in the displacement data as received signal strength, and the displacement of the RSSI value is calculated for each of the plurality of communication devices A, B, C, and D.

  The direction estimation unit 43 has a function of estimating the moving direction of the terminal device 20 based on a combined vector RV obtained by combining the displacement vectors DV1, DV2, DV3, DV4 for each of the plurality of communication devices 10.

The function of the direction estimation means 43 is implement | achieved as follows, for example. As shown in FIG. 7, the CPU 21 of the terminal device 20 generates a combined vector RV by combining the displacement vectors DV1, DV2, DV3, DV4 on the xy plane. And CPU21 estimates the moving direction of the terminal device 20 from a 1st timing to a 2nd timing by calculating | requiring the inclination (here, the angle | corner which synthetic | combination vector RV and the x-axis) (theta) make | form. The slope θ is obtained by calculating θ satisfying the following expression (1), where u is the combined vector RV and v is the unit vector in the x-axis direction.

  The position estimation unit 44 has a function of estimating the position of the terminal device 20 at the second timing based on the estimated moving direction.

The function of the position estimation means 44 is implement | achieved as follows, for example. When the CPU 21 of the terminal device 20 estimates the moving direction of the terminal device 20 based on the function of the direction estimating means 43, the movement of the terminal device 20 from the first timing to the second timing is detected using the detection data of the acceleration sensor 28. Estimate distance. Here, the moving distance d _n (n is an integer equal to or greater than 0) of the terminal device 20 is expressed as the following Expression (2).
d _n = s _n × l _n (2)

Wherein (2), s _n indicates the number of steps of the user carrying the terminal unit 20, l _n indicates the stride of the user. For example, the _number of steps sn may be increased by one each time the value of the detection data (that is, acceleration) of the acceleration sensor 28 reaches a predetermined threshold value or more. Further, step length l _n are, for example, may be a value that is appropriately set according to the size of the user's body, may be a fixed value.

Next, the CPU 21 determines the position of the terminal device 20 at the second timing using the position of the terminal device 20 at the first timing, the moving direction of the terminal device 20, and the moving distance of the terminal device 20. Here, _assuming that the position of the terminal device 20 at the first timing is P _n = (x _n , y _n ) and the moving direction of the terminal device 20 from the first timing to the second timing is θ _n , the terminal at the second timing The position P _{n + 1} of the device 20 is shown as the following equation (3).
P _{n + 1} = (x _n + d _n cos θ _n , y _n + d _n sin θ _n ) (3)

Here, an example of the estimated position of the terminal device 20 will be described with reference to FIG. Here, the initial position of the terminal device 20 in the space S is assumed to be P ₀ = (x ₀ , y ₀ ). The terminal device 20 exists at the position P ₀ at the first timing, the moving distance of the terminal device 20 from the first timing to the second timing is d ₀ , and the movement of the terminal device 20 from the first timing to the second timing When the direction is θ ₀ , the position P ₁ of the terminal device 20 at the second timing is P ₁ = (x ₁ , y ₁ ) = (x ₀ + d ₀ cos θ ₀ , y ₀ + d ₀ sin θ ₀ ). Indicated.

Next, when the position P ₁ is the position of the terminal device 20 at the first timing, the position P ₂ of the terminal 20 at the second timing is P ₂ = (x ₂ , y ₂ ) = (x ₁ + d ₁ cos θ ₁ , y ₁ + d ₁ sin θ ₁ ). In this way, the CPU 21 repeatedly estimates the position of the terminal device 20 over time.

(4) Flow of main processes of position estimation system of this embodiment Next, an example of the flow of the main processes performed by the position estimation system of this embodiment is demonstrated with reference to the flowchart of FIG.

  First, every time the CPU 21 of the terminal device 20 receives a radio wave transmitted from each communication device 10, the RSSI value detected by the communication interface unit 29 corresponds to the identification information of the communication device 10 that has transmitted the radio wave. In addition, for example, it is stored in the RAM 23.

  Next, the CPU 21 of the terminal device 20 determines the terminal device at the first timing based on the information regarding the received signal strength acquired at the first timing and the information regarding the received signal strength acquired at the second timing after the first timing. Displacement vectors DV1, DV2, DV3, DV4 starting at position 20 are generated for each of the plurality of communication devices A, B, C, D (step S102).

  Specifically, the CPU 31 of the terminal device 20 stores the RSSI value of the radio wave received from each of the plurality of communication devices A, B, C, and D at the first timing in the RAM 23 based on the function of the acquisition unit 41. Then, the RSSI value stored in the RAM 23 is stored in the displacement data. Further, the CPU 21 acquires the RSSI value of the radio wave received from each of the plurality of communication devices A, B, C, and D at the second timing after the first timing (for example, 1 second after the first timing), and stores it in the RAM 23. If it memorize | stores, the RSSI value memorize | stored in RAM23 will be memorize | stored in displacement data as a received signal strength for every some communication apparatus A, B, C, D in 2nd timing. Then, the CPU 21 of the terminal device 20 generates a displacement vector starting from the position P of the terminal device 20 at the first timing for each of the plurality of communication devices A, B, C, and D.

  Next, the CPU 21 of the terminal device 20 estimates the moving direction of the terminal device 20 based on the combined vector RV obtained by combining the displacement vectors DV1, DV2, DV3, DV4 for each of the plurality of communication devices 10 (step S104).

  More specifically, the CPU 21 of the terminal device 20 generates a combined vector RV by combining the displacement vectors DV1, DV2, DV3, DV4. And CPU21 estimates the moving direction of the terminal device 20 from a 1st timing to a 2nd timing by calculating | requiring the inclination (here, the angle | corner which synthetic | combination vector RV and x-axis make) (theta) of synthetic | combination vector RV.

  Next, the CPU 21 of the terminal device 20 estimates the position of the terminal device 20 at the second timing based on the estimated moving direction (step S106). More specifically, the CPU 31 positions the terminal device 20 at the first timing, the moving direction of the terminal device 20 from the first timing to the second timing, and the terminal device 20 from the first timing to the second timing. The position of the terminal device 20 at the second timing is obtained using the movement distance.

  When a predetermined time (for example, 1 second) has elapsed after the process of step S106 (step S108: YES), the CPU 21 of the terminal device 20 proceeds to the process of step S100. As a result, the CPU 21 repeatedly estimates the position of the terminal device 20 over time.

  As described above, according to the position estimation system, the position estimation method, and the program of the present embodiment, the displacement corresponding to each of the plurality of communication devices 10 based on the information related to the received signal strength of the radio wave received by the terminal device 20. Since the vectors DV1, DV2, DV3, DV4 are generated and the moving direction of the terminal device 20 is estimated based on the combined vector RV generated based on these displacement vectors DV1, DV2, DV3, DV4, the terminal device 20 It is possible to estimate the moving direction of the terminal device 20 based on the received signal strength of the radio wave received. Here, when estimating the moving direction of the terminal device 20 using the received signal strength, for example, regardless of whether the moving direction of the terminal device 20 matches the direction in which the terminal device 20 faces, Since it is considered that the received signal strength can be obtained, for example, compared with the case where the moving direction of the terminal device 20 is estimated using a direction sensor such as a gyro sensor or a geomagnetic sensor, the influence of the possessing mode of the terminal device 20 is suppressed. be able to. For this reason, the moving direction of the terminal device 20 can be estimated accurately. Moreover, in this embodiment, since the position of the terminal device 20 is estimated based on the movement direction estimated in this way, the position of the terminal device 20 existing in the space S (that is, the position of the user) is accurately determined. Can be estimated.

Hereinafter, modifications of the above-described embodiment will be described.
(Modification 1)
In the above-described embodiment, the acquisition unit 41 has been described as an example of the case where the terminal device 20 acquires information on the received signal strength over time when the terminal device 20 receives radio waves transmitted from the plurality of communication devices 10. Not limited to. For example, the acquisition unit 41 may acquire information related to received signal strength when a plurality of communication devices 10 receive radio waves transmitted from the terminal device 20. In this case, each communication device 10 may be provided with an RSSI circuit that detects the value of the received signal strength when a radio wave transmitted from the terminal device 20 is received, similarly to the terminal device 20.

  In this case, as a function of the acquisition unit 41, the CPU 21 of the terminal device 20 requests each communication device 10 to transmit the RSSI value of the radio wave received from the terminal device 20 to the terminal device 20. And CPU21 will memorize | store the received information in RAM23, for example, if the information transmitted from each communication apparatus 10 is received (acquisition) via the communication interface part 29. FIG. The functions of the generation unit 42, the direction estimation unit 43, and the position estimation unit 44 are the same as those in the above-described embodiment.

  As described above, according to the position estimation system, the position estimation method, and the program according to the present modification, it is possible to exert the same effects as those of the above-described embodiment.

(Modification 2)
In the above-described embodiment, the position estimation means 44 is a terminal device at the second timing when the received signal strength corresponding to at least one of the plurality of communication devices 10 is equal to or greater than a predetermined threshold at the second timing. The 20 positions may be estimated as predetermined positions.

  For example, every time the position of the terminal device 20 is estimated, if an error occurs between the accurate position of the terminal device 20 and the estimated position, the error is accumulated every time the position of the terminal device 20 is repeatedly estimated. Since the position of the terminal device 20 is estimated in the state, it may be difficult to accurately estimate the position of the terminal device 20. By the way, the received signal strength of radio waves transmitted and received between the terminal device 20 and the communication device 10 becomes higher as these distances become shorter, and becomes smaller as these distances become longer. The distance between the device 20 and the communication device 10 can be estimated.

  According to this modification, for example, when the received signal strength at the second timing is greater than or equal to a predetermined threshold value, the position of the terminal device 20 at the second timing corresponds to the predetermined position (for example, the received signal strength equal to or greater than the threshold value). Therefore, the position of the terminal device 20 can be accurately estimated based on the relationship between the distance between the terminal device 20 and the communication device 10 and the received signal strength. Thereby, for example, even when an error occurs between the accurate position of the terminal device 20 and the estimated position, it is possible to prevent the position of the terminal device 20 from being newly estimated in a state where this error is accumulated. can do.

  The function of the position estimation means 44 in this modification is implement | achieved as follows, for example. The CPU 21 of the terminal device 20 accesses the displacement data, and among the communication devices A, B, C, and D, the communication device (for example, the communication device D) whose received signal strength value at the second timing is equal to or greater than a predetermined threshold value. Is present, the position of the terminal device 20 is estimated to be a predetermined position (for example, the position of the communication device D).

  In addition, when there are two communication devices whose received signal strength values at the second timing are equal to or higher than a predetermined threshold among the communication devices A, B, C, and D, the CPU 31 may, for example, You may estimate the position used as the center between communication apparatuses as a position of the terminal device 20. FIG. Further, when there are three communication devices having a received signal strength value at the second timing equal to or greater than a predetermined threshold among the communication devices A, B, C, and D, for example, the CPU 31 You may estimate the position used as the center between communication apparatuses as a position of the terminal device 20. FIG.

  Further, the position estimation unit 44 calculates the average value of the received signal strength corresponding to at least one communication device 10 among the plurality of communication devices 10 in the second period before the second timing (for example, the past one second including the second timing). When is equal to or greater than a predetermined threshold value, the position of the terminal device 20 at the second timing may be estimated as a predetermined position. Thereby, for example, even if the received signal strength is an abnormal value that instantaneously exceeds a predetermined threshold value, if the average received signal strength is equal to or lower than the threshold value, the terminal device 20 is erroneously placed at a predetermined position. Can be suppressed.

  The function of the position estimating means 44 in this case is realized as follows, for example. Here, for example, as shown in FIG. 10, the displacement data includes an average value of RSSI values within a first period before the first timing (for example, the past one second including the first timing) and an RSSI value within the second period. And the displacement of the average RSSI value between the first period and the second period may be described for each of the plurality of communication devices A, B, C, and D. The CPU 31 accesses the displacement data, and among the communication devices A, B, C, and D, there is a communication device (for example, the communication device D) in which the average value of the received signal intensity in the second period is equal to or greater than a predetermined threshold. In this case, the position of the terminal device 20 may be estimated to a predetermined position (for example, the position of the communication device D).

(Modification 3)
In the above embodiment, the generation unit 42 receives the average value of the received signal strength corresponding to each of the plurality of communication devices 10 within the first period before the first timing and the received signal corresponding to each of the plurality of communication devices 10. The displacement vector may be generated for each of the plurality of communication devices 10 based on the average value in the second period before the second timing of the intensity.

  For example, when the received signal strength acquired at least one of the first timing and the second timing is an abnormal value, the received signal strength is used as it is for estimation of the moving direction, thereby degrading the estimation accuracy of the moving direction, and consequently There is a possibility that the estimation accuracy of the position of the terminal device 20 may deteriorate. According to this modification, since the position of the terminal device 20 can be estimated based on the average value of the received signal strength corresponding to each of the plurality of communication devices 10, for example, the abnormal value of the received signal strength is the first period. Even when included in at least one of the second periods, the influence of the abnormal value can be reduced by averaging the received signal intensity in each period. As a result, it is possible to suppress the deterioration of the estimation accuracy of the moving direction based on the abnormal value of the received signal strength, and thereby suppress the deterioration of the estimation accuracy of the position of the terminal device 20.

  The function of the production | generation means 42 in this modification is implement | achieved as follows, for example. When the CPU 21 of the terminal device 20 acquires the RSSI values of the radio waves received from each of the plurality of communication devices A, B, C, D at the first timing based on the function of the acquisition unit 41, the plurality of communication devices A, For each of B, C, and D, an average value within a first period (for example, the past one second including the first timing) of the RSSI value before the first timing is obtained. And CPU21 memorize | stores the average value of an RSSI value in the displacement data shown, for example in FIG. Further, when the CPU 21 acquires the RSSI value of the radio wave received from each of the plurality of communication devices A, B, C, D at the second timing based on the function of the acquisition unit 41, the plurality of communication devices A, B, For each of C and D, an average value within the second period (for example, the past one second including the second timing) before the second timing of the RSSI value is obtained. And CPU21 memorize | stores the average value of an RSSI value in displacement data. The contents of the process for generating the displacement vector are the same as in the above-described embodiment.

  In addition, the generation unit 42 generates an exponential smoothed average value within a first period before the first timing of the received signal strength corresponding to each of the plurality of communication devices 10 and the received signal strength corresponding to each of the plurality of communication devices 10. The displacement vector may be generated for each of the plurality of communication devices 10 based on the exponential smoothed average value in the second period before the second timing. Even in this case, it is possible to suppress the deterioration of the estimation accuracy of the moving direction based on the abnormal value of the received signal strength, and thus the deterioration of the estimation accuracy of the position of the terminal device 20 can be suppressed.

  In this case, when the CPU 21 of the terminal device 20 acquires the RSSI value of the radio wave received from each of the plurality of communication devices A, B, C, and D at the first timing, for each of the plurality of communication devices A, B, C, and D. Then, an exponential smoothing average value within a first period (for example, the past 10 seconds including the first timing) before the first timing of the RSSI value is obtained. And CPU21 may memorize | store the exponential smoothing average value of an RSSI value in displacement data, for example. Further, when the CPU 21 acquires the RSSI value of the radio wave received from each of the plurality of communication devices A, B, C, and D at the second timing, the CPU 21 obtains the RSSI value for each of the plurality of communication devices A, B, C, and D. An exponential smoothing average value within a second period (for example, the past 10 seconds including the second timing) before two timings is obtained. Then, the CPU 21 may store the exponential smoothed average value of the RSSI values in the displacement data.

  In addition, when estimating the moving direction of the terminal device 20 based on the exponential smoothing average value of the RSSI value, the start period of the second period may be the same as or different from the start period of the first period. Good. Moreover, you may estimate the moving direction of the terminal device 20 based on the exponential smoothing average value of the predetermined period B (for example, 10 seconds) of the average value of the RSSI value for the predetermined period A (for example, 1 second).

(Modification 4)
In the above embodiment, the case where the number of communication devices 10 is three or more has been described as an example, but the number of communication devices 10 may be two. In this case, it is possible to estimate the position of the terminal device 20 in a linear space connecting the two communication devices A and B shown in FIG. 11 by performing the same processing as in the above embodiment.

(Modification 5)
In the said embodiment, a displacement vector represents the displacement of the distance of any one of the some communication apparatuses 10 from the 1st timing to the 2nd timing, and the terminal device 20, and the direction estimation means 43 is the following. Based on the combined vector, the moving direction and moving distance of the terminal device 20 are estimated, and the position estimating means 44 estimates the position of the terminal device 20 at the second timing based on the estimated moving direction and moving distance. Also good.

  According to this modification, the terminal device 20 uses the combined vector obtained by combining the displacement vectors representing the displacement from the first timing to the second timing of the distance between each of the plurality of communication devices 10 and the terminal device 20. Since it is possible to represent not only the moving direction but also the moving distance of the terminal device 20 from the first timing to the second timing, it is possible to estimate the end point of this combined vector as the position of the terminal device 20 at the second timing. it can. Thereby, since the position of the terminal device 20 can be estimated without using a device for measuring a moving distance such as an acceleration sensor, the position of the terminal device 20 can be easily estimated, and the position estimation system The manufacturing cost can be reduced.

式（４）中、Ｐ_ｒはＲＳＳＩを示し、Ｐ_ｔは通信装置１０の送信電力（ｄＢｍ）を示し、Ｇ_ｒは端末装置２０の受信アンテナの利得（ｄＢｉ）を示し、Ｇ_ｔは通信装置１０の送信アンテナの利得（ｄＢｉ）を示し、Ｌは自由空間損失（ｄＢｍ）を示している。このＬは式（５）でもとめられ、式（５）中、ｄは通信装置１０と端末装置２０との距離（ｍ）を示し、ｆは電波の周波数（Ｈｚ）を示し、ｃは光速（＝２．９９７９２４５８×１０^８）（ｍ／ｓ）を示している。式（４）及び（５）によってもとめられる距離とＲＳＳＩ値の関係は、例えば図１２に示す対数関数で表される。 The function of the production | generation means 42 in this modification is implement | achieved as follows, for example. When the CPU 21 of the terminal device 20 acquires the RSSI value (information on the received signal strength) from each communication device 10 at the first timing based on the function of the acquisition unit 41, each communication device 10 uses the acquired RSSI value. And the distance between the terminal device 20 and the terminal device 20. Here, the distance between one communication device 10 and the terminal device 20 may be obtained, for example, by actually measuring the relationship between the distance and the RSSI value in advance. In addition, the relationship between the two can be determined more accurately by using the following equations (4) and (5).
_{P r = P t + G r} + G t -L ... (4)

Wherein (4), _{P r} represents the RSSI, _{P t} represents the transmission power of the communication device 10 (dBm), _{G r} represents a receiving antenna gain of the terminal device 20 (dBi), _{G t} is the communication device 10 indicates the gain (dBm) of the transmitting antenna, and L indicates the free space loss (dBm). This L can also be obtained from equation (5). In equation (5), d represents the distance (m) between the communication device 10 and the terminal device 20, f represents the frequency (Hz) of the radio wave, and c represents the speed of light ( = 2.99794584 × 10 ⁸ ) (m / s). The relationship between the distance and the RSSI value obtained by the equations (4) and (5) is expressed by, for example, a logarithmic function shown in FIG.

  CPU21 will memorize | store the calculated distance in the displacement data shown, for example in FIG. 13, if the distance of each communication apparatus 10 and the terminal device 20 in a 1st timing is calculated | required. The displacement data in this modification includes the distance between the communication device 10 and the terminal device 20 at the first timing, the distance between the communication device 10 and the terminal device 20 at the second timing, the first timing, and the second timing. Is the data described for each of a plurality of communication devices (A, B, C, D in the example of the figure).

  Next, the CPU 21 of the terminal device 20 acquires the RSSI value of the radio wave received from each of the plurality of communication devices A, B, C, and D at the second timing after the first timing based on the function of the acquisition unit 41. Then, using the acquired RSSI value, the distance between each communication device A, B, C, D and the terminal device 20 is obtained, and the obtained distance is stored in the displacement data. And CPU21 calculates the displacement value of the distance between 1st timing and 2nd timing for every some communication apparatus A, B, C, D, and memorize | stores the calculated displacement value in displacement data.

  Then, the CPU 21 of the terminal device 20 generates a displacement vector starting from the position of the terminal device 20 at the first timing for each of the plurality of communication devices A, B, C, and D on the xy plane. These displacement vectors are generated in the same manner as the displacement vectors DV1 to DV4 shown in FIG.

  In this modification, the direction estimation means 43 has a function of estimating the moving direction and moving distance of the terminal device 20 based on a combined vector obtained by combining displacement vectors for a plurality of communication devices A, B, C, and D. .

  The function of the direction estimation means 43 is implement | achieved as follows, for example. The CPU 21 of the terminal device 20 generates a combined vector by combining each displacement vector in the xy plane. This composite vector is generated in the same manner as the composite vector RV shown in FIG. And CPU21 estimates the moving direction of the terminal device 20 from a 1st timing to a 2nd timing by calculating | requiring the inclination of a synthetic | combination vector using Formula (1) mentioned above. Further, the CPU 21 estimates the moving distance of the terminal 20 from the first timing to the second timing by determining the size of the combined vector.

  In the present modification, the position estimation unit 44 has a function of estimating the position of the terminal device 20 at the second timing based on the estimated moving direction and moving distance.

The function of the position estimation means 44 is implement | achieved as follows, for example. When the CPU 21 of the terminal device 20 estimates the moving direction and moving distance of the terminal device 20 based on the function of the direction estimating means 43, the CPU 21 estimates the position of the end point of the combined vector as the position of the terminal device 20 at the second timing. Here, the position of the end point of the combined vector is the position of the terminal device 20 at the first timing P _n = (x _n , y _n ) (n is an integer of 0 or more), and the terminals from the first timing to the second timing the direction of movement of the device 20 theta _n, when the moving distance of the terminal device 20 from the first timing to the second timing and d _n, is determined in the same manner as the above expression (3).

(Modification 6)
A functional block diagram of this modification is shown in FIG. As shown in FIG. 14, this functional block diagram is different from that shown in FIG. 3 in that a correction means 45 is added.

  In the fifth modification described above, when the information about the received signal strength is acquired, the generating device includes a correcting unit 45 that corrects the received signal strength based on a difference between the received signal strength and a predetermined reference value of the received signal strength. 42, based on the received signal strength acquired at the first timing and corrected reception signal strength, and the received signal strength acquired at the second timing and corrected received signal strength information, A displacement vector may be generated for each of the plurality of communication devices 10.

  The relationship between the distance between the terminal device and the communication device and the received signal strength may be different for each type and / or individual of the terminal device or the communication device, and may be different depending on the environment around the terminal device or the communication device. For example, when estimating the position of the second terminal device different from the first terminal device using the relationship between the distance between the first terminal device and the communication device and the received signal strength, the second terminal Even if the device exists at the same position as the first terminal device, the distance between the second terminal device and the communication device determined based on the above relationship is different from the distance between the first terminal device and the communication device. There is a case. In this case, since it can be estimated that the second terminal device is located at a different position from the first terminal device, there is a possibility that the position of the terminal device cannot be estimated accurately.

  According to the present modification, when the information on the received signal strength is acquired, the received signal strength is corrected based on the difference between the received signal strength and the predetermined reference value of the received signal strength. Even when the device 20 or the communication device 10 is used or when the environment around the terminal device 20 or the communication device 10 is different, the received signal strength is corrected so as to conform to the predetermined relationship between the distance and the received signal strength. By doing so, it is possible to reduce the difference in the relationship between the distance and the reception signal based on the difference in the type or environment of the terminal device 20 or the communication device 10, and thus accurately estimate the position of the terminal device 20. it can. Therefore, the position of the terminal device 20 can be accurately estimated regardless of the type and / or individual of the terminal device 20 or the communication device 10 and the environment around the terminal device 20 or the communication device 10. .

  The correction unit 45 has a function of correcting the received signal strength based on a difference between the received signal strength and a predetermined reference value of the received signal strength when information on the received signal strength is acquired.

  The function of the correction means 45 is implement | achieved as follows, for example. When the CPU 21 of the terminal device 20 acquires the RSSI value (information on the received signal strength) from each communication device 10 based on the function of the acquisition unit 41, the acquired RSSI value is corrected. By the way, the slopes of a plurality of logarithmic functions each representing the relationship between the RSSI value and the distance are, for example, as shown in FIG. 15, for each type and / or individual of the terminal device 20 or the communication device 10, or for the terminal device 20. Or, it is the same without depending on the environment around the communication device 10. That is, a logarithmic function (indicated by a solid line in FIG. 15) indicating a predetermined relationship between the RSSI value and the distance, and another relationship between the RSSI value and the distance (for example, the type or environment of the terminal device 20 or the communication device 10) The difference CV of the RSSI value between the logarithmic function (represented by a one-dot chain line in FIG. 15) indicating the RSSI value and the distance in different cases is the same value even if the distance changes. Therefore, the terminal device 20 or the communication device is corrected by correcting the RSSI value by using the difference CV between the reference value (for example, theoretical value) of the RSSI value at a predetermined position in the space S and the actual measured value of the RSSI value at the position. It is possible to reduce the difference in the relationship between the distance and the received signal based on the difference between the ten types and environments.

  The CPU 21 may obtain in advance a reference value (for example, theoretical value) of the RSSI value at a predetermined position in the space S using the above-described equations (4) and (5). Further, for example, when the actual measured value of the RSSI value at the predetermined position is input using the input unit 27, the CPU 21 obtains the difference CV between the actual measured value of the RSSI value and the reference value of the RSSI value. Good. Further, the CPU 21 may capture the difference CV in advance. And when CPU21 acquires an RSSI value from the communication apparatus 10, it will correct | amend the acquired RSSI value using difference CV so that the acquired RSSI value may match a reference value (In the example of FIG. 15, it acquired. Add the value of the difference CV to the RSSI value).

  Note that the CPU 21 may obtain a new difference CV using an exponential smoothing method, a moving average method, or the like using the difference CV that has been determined in the past.

  In the present modification, the generating means 42 receives the received signal intensity acquired at the first timing and corrected reception signal intensity, and the received signal intensity acquired at the second timing and corrected received signal intensity. And a function of generating a displacement vector for each of the plurality of communication devices 10 based on the information on the information.

  The function of the production | generation means 42 in this modification is implement | achieved as follows, for example. When the CPU 21 of the terminal device 20 corrects the RSSI value (information on the received signal strength) acquired from each communication device 10 at the first timing based on the function of the correction unit 45, each communication is performed using the corrected RSSI value. The distance between the device 10 and the terminal device 20 is obtained. Further, when determining the distance between each communication device 10 and the terminal device 20 at the first timing, the CPU 21 stores the determined distance in, for example, displacement data illustrated in FIG.

  Next, when the CPU 21 of the terminal device 20 corrects the RSSI values acquired from the plurality of communication devices 10 at the second timing after the first timing based on the function of the correcting unit 45, each of the CPUs 21 uses the corrected RSSI values. The distance between the communication device 10 and the terminal device 20 is obtained, and the obtained distance is stored in the displacement data. And CPU21 calculates the displacement value of the distance between 1st timing and 2nd timing for every some communication apparatus 10, and memorize | stores the calculated displacement value in displacement data. Note that the functions of the direction estimating unit 43 and the position estimating unit 44 in the present modification may be the same as those in the fifth modification described above.

  The program of the present invention may be stored in a computer-readable storage medium. The storage medium storing this program may be the nonvolatile memory 24 shown in FIG. Further, it may be a CD-ROM that can be read by being inserted into a program reading device such as a CD-ROM drive. Further, the storage medium may be a magnetic tape, a cassette tape, a flexible disk, an MO / MD / DVD, or a semiconductor memory.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, in each of the above-described embodiments, the case of estimating the moving direction of one terminal device 20 has been described as an example. However, the moving directions of a plurality of terminal devices (that is, the moving directions of a plurality of users) are estimated. May be. In this case, the types of the plurality of terminal devices may be the same or different. Even in this case, the moving direction of each terminal device (that is, the moving direction of each user) can be accurately determined by collecting the combined vector obtained by combining the displacement vectors of the plurality of communication devices 10 for each of the plurality of terminal devices. Can be estimated.

  In the embodiment and the modification described above, the terminal device 20 is configured to implement the functions of the acquisition unit 41, the generation unit 42, the direction estimation unit 43, the position estimation unit 44, and the correction unit 45. I can't. For example, each of the means 41, 42, 43, 44, 45 is performed by a computer (for example, a general-purpose personal computer) that is communicably connected to the terminal device 20 via a communication network such as the Internet or a LAN (Local Area Network). It is good also as a structure which implement | achieves these functions. Moreover, it is good also as a structure which implement | achieves the function of at least one means among each said means 41, 42, 43, 44, 45 by the said computer. Further, all of these means may be realized by the communication device 10 or the terminal device 20, or at least a part of the means may be realized by the communication device 10 or the terminal device 20.

  The position estimation system, position estimation method, and program of the present invention as described above can accurately estimate the position of a terminal device existing in a predetermined space. For example, a position information service indoors such as in an actual store Therefore, the industrial applicability is extremely large.

DESCRIPTION OF SYMBOLS 10 ... Communication apparatus 20 ... Terminal device 41 ... Acquisition means 42 ... Generation means 43 ... Direction estimation means 44 ... Position estimation means 45 ... Correction means DV1, DV2, DV3, DV4 ... Displacement vector RV ... Composite vector S ... Space

Claims (8)

A position estimation system for estimating a position of a terminal device existing in a predetermined space,
Information on received signal strength when the terminal device receives radio waves transmitted from a plurality of communication devices provided in the space, or the plurality of communication devices received radio waves transmitted from the terminal device Acquisition means for acquiring information on received signal strength over time,
Based on the information on the received signal strength acquired at the first timing and the information on the received signal strength acquired at the second timing after the first timing, the displacement starting from the position of the terminal device at the first timing Generating means for generating a vector for each of the plurality of communication devices;
Direction estimation means for estimating a moving direction of the terminal device based on a combined vector obtained by combining displacement vectors for the plurality of communication devices;
Position estimating means for estimating the position of the terminal device at the second timing based on the estimated moving direction;
A position estimation system comprising: The displacement vector represents a displacement of a distance between any one of the plurality of communication devices and the terminal device from the first timing to the second timing,
The direction estimating means estimates a moving direction and a moving distance of the terminal device based on the combined vector,
The position estimation system according to claim 1, wherein the position estimation unit estimates the position of the terminal device at the second timing based on the estimated moving direction and moving distance. When obtaining information on the received signal strength, comprising correction means for correcting the received signal strength based on the difference between the received signal strength and a predetermined reference value of the received signal strength,
The generating means includes information on the received signal strength that is acquired at the first timing and corrected, and information on the received signal strength that is acquired at the second timing and corrected. The position estimation system according to claim 2, wherein the displacement vector is generated for each of the plurality of communication devices based on.   The position estimation means determines the position of the terminal device at the second timing when the received signal strength corresponding to at least one communication device of the plurality of communication devices is equal to or greater than a predetermined threshold at the second timing. The position estimation system according to claim 1, wherein the position estimation system is estimated to a predetermined position.   The generating means includes an average value of received signal strengths corresponding to each of the plurality of communication devices in a first period before the first timing, and the received signal strengths corresponding to each of the plurality of communication devices. The position estimation system according to claim 1, wherein the displacement vector is generated for each of the plurality of communication devices based on an average value in a second period before two timings.   The position estimation system according to claim 1, wherein three or more communication devices are provided in the space. A position estimation method for causing a computer to estimate the position of a terminal device existing in a predetermined space,
The computer
Information on received signal strength when the terminal device receives radio waves transmitted from a plurality of communication devices provided in the space, or the plurality of communication devices received radio waves transmitted from the terminal device Obtaining information about received signal strength over time,
Based on the information on the received signal strength acquired at the first timing and the information on the received signal strength acquired at the second timing after the first timing, the displacement starting from the position of the terminal device at the first timing Generating a vector for each of the plurality of communication devices;
Estimating a moving direction of the terminal device based on a combined vector obtained by combining displacement vectors for the plurality of communication devices;
Estimating the position of the terminal device at the second timing based on the estimated moving direction;
A position estimation method for executing each of the steps. A program for causing a computer to estimate the position of a terminal device existing in a predetermined space,
In the computer,
Information on received signal strength when the terminal device receives radio waves transmitted from a plurality of communication devices provided in the space, or the plurality of communication devices received radio waves transmitted from the terminal device A function to obtain information on the received signal strength over time,
Based on the information on the received signal strength acquired at the first timing and the information on the received signal strength acquired at the second timing after the first timing, the displacement starting from the position of the terminal device at the first timing A function of generating a vector for each of the plurality of communication devices;
The function of estimating the moving direction of the terminal device based on a combined vector obtained by combining the displacement vectors of the plurality of communication devices, and the position of the terminal device at the second timing based on the estimated moving direction. Function to estimate,
A program to realize

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