WO2018062435A1 - Positioning system, positioning device, and computer program - Google Patents

Abstract

A positioning system 1 includes: at least an N quantity (where, N is an integer of 4 or more) of receivers 20-A, 20-B, etc., which respectively receive signal waves output from a wave source, wherein each of said receivers receives signal waves output from the wave source and outputs data indicating the reception strength of said signal waves; and a computation circuit 31 that receives the data indicating the reception strength of signal waves from each of the receivers, and utilizes the received N items of data to estimate the wave source position. The computation circuit 31 provisionally estimates, for each of K sets (where, K is an integer of 2 or more) of data groups that respectively include three or more items of data selected from the received N items of data, wave source positions utilizing the three or more items of data in each set, and then estimates the wave source position on the basis of two or more provisionally estimated wave source positions. At least one among the N items of data is duplicated and included in a plurality of sets.

Description

Positioning system, positioning device and computer program

The present disclosure relates to a positioning system, a positioning device, and a computer program.

Conventionally, a positioning system for positioning an object has been developed (for example, Patent Documents 1 and 2).

In recent years, positioning systems using the Bluetooth (registered trademark, the same applies hereinafter) standard is becoming popular. More specifically, among the Bluetooth standards, a BLE positioning system that estimates the position of a signal generator using a signal generator that generates a signal of Bluetooth Low Energy (hereinafter abbreviated as “BLE”) standard. Is spreading.

Many of the BLE positioning systems employ measurement processing using a three-point positioning algorithm. The measurement process by the three-point positioning algorithm uses coordinate information indicating the installation positions of the three receivers and information on the distances between the signal generator and each receiver. The positioning system performs a predetermined calculation and outputs the absolute position coordinates of the signal generator as a solution of the ternary simultaneous nonlinear equation.

JP 2012-198066 A JP-A-11-160409

The three-point positioning algorithm needs to calculate the solution of the ternary nonlinear equation. However, it is difficult to solve the ternary nonlinear equations. For this reason, the Newton method is generally used that uses an inverse matrix operation of a partial differential matrix and its repeated operation.

In the conventional Newton method, it was necessary to increase the number of receivers in order to sufficiently acquire the received intensity data used for the calculation. Therefore, it has been demanded to suppress an increase in cost and installation range.

One non-limiting exemplary embodiment of the present application provides a positioning system that can suppress an increase in the number of receivers.

According to an exemplary embodiment of the present invention, the positioning system includes a plurality of receivers (N is an integer of 4 or more) each receiving a signal wave output from a wave source, each of which includes: A plurality of receivers that receive the signal wave output from the wave source and output data indicating the reception intensity of the signal wave, and receive and receive data indicating the reception intensity of the signal wave from each of the plurality of receivers A calculation circuit for estimating the position of the wave source using N data, wherein the calculation circuit includes K sets of data each including three or more data selected from the received N data. For the data group (K: integer of 2 or more), the position of the wave source is provisionally estimated for each set using three or more data of each set, and the position of the wave source based on the two or more provisionally estimated positions is Estimate the position of the wave source, and At least one Chino include redundantly in a plurality of groups.

According to the exemplary embodiment of the present invention, the arithmetic circuit temporarily estimates the position of the wave source for each set using three or more data included in the K sets of data groups (K: an integer equal to or greater than 2). Then, the position of the tsunami source is estimated based on the positions of the two or more tentatively estimated wave sources. Each of the K sets of data groups includes three or more data selected from the N data received from the N receivers. At least one of the N pieces of data is included in a plurality of sets. Since at least one piece of data is included in a plurality of sets, the provisional estimation result of the position of the wave source can be increased while suppressing an increase in the number of receivers as compared with the conventional method that does not allow duplication. For example, when the average value of the temporary estimation results is estimated as the position of the wave source, the parameter of the temporary estimation results can be increased, and the accuracy can be improved.

FIG. 1 is a diagram schematically illustrating a configuration of a positioning system 1 according to an exemplary embodiment of the present invention. FIG. 2 is a diagram illustrating a first example of an environment in which the positioning system 1 is introduced. FIG. 3 is a diagram illustrating a second example of the environment in which the positioning system 1 is introduced. FIG. 4 is a diagram showing four shelves including shelves 22 and 23 in FIGS. 2 and 3. FIG. 5 is a view showing the signal generator 10 attached to the product 24 a placed on the shelf 25. FIG. 6 is a diagram showing the signal generator 10 mounted on a self-propelled vehicle 24 b that travels between the shelves 22 and 23. FIG. 7 is a diagram showing the signal generator 10 mounted on a smartphone 24c of a shopper walking between shelves 22 and 23. As shown in FIG. FIG. 8 is a diagram illustrating a hardware configuration of the signal generator 10. FIG. 9 is a diagram illustrating a hardware configuration of the positioning device 30. FIG. 10 is a diagram illustrating an example of three receivers that output three reception intensity data used for three-point positioning. FIG. 11 is a diagram illustrating an example of three receivers that output three reception intensity data used for three-point positioning. FIG. 12 is a diagram illustrating an example of three receivers that output three reception intensity data used for three-point positioning. FIG. 13 shows three receivers 20-A, 20-B and 20-C located at different distances from the wave source P. FIG. FIG. 14 is a diagram mainly illustrating a configuration of a processing block of the CPU 31. FIG. 15 is a diagram illustrating a configuration of the three-point positioning processing block 42 that performs temporary estimation. FIG. 16 is a flowchart showing a processing procedure of the positioning device 30. FIG. 17 is a diagram illustrating a positional relationship between the wave source position P and each receiver. FIG. 18 is a diagram showing a configuration of the five-point positioning block 50. As shown in FIG. FIG. 19 is a flowchart showing a processing procedure of the CPU 31 functioning as the five-point positioning block 50.

The inventor of the present application has repeatedly studied a positioning algorithm that can reduce a positioning error while reducing a load of calculation processing. As a result, a new positioning algorithm was constructed, and a positioning system that implemented the positioning algorithm was completed.

In the positioning system according to the present disclosure, a plurality of receivers of N units (N is an integer of 4 or more) receive signal waves output from the wave source. The wave source is a signal generator that outputs signal waves such as electromagnetic waves and sound waves.

Each receiver receives the signal wave output from the wave source and outputs data (reception intensity data) indicating the reception intensity of the signal wave. The arithmetic circuit receives the reception intensity data of the signal wave from each of the plurality of receivers, and estimates the position of the wave source using the received N pieces of data. More specifically, the arithmetic circuit, for each of K sets of data groups (K: an integer of 2 or more), each including three or more data selected from the received N data, Using the above data, the position of the wave source is temporarily estimated for each set. Further, the arithmetic circuit estimates the position of the wave source based on the temporarily estimated positions of the two or more wave sources. In the present specification, estimating the position of the wave source for each set is referred to as “temporary estimation”, and determining the position of one wave source from a plurality of temporarily estimated positions is referred to as “ This is called “estimation”.

The arithmetic circuit may estimate an average value of the coordinates of the two or more wave source positions temporarily estimated as the wave source position, or may estimate the median value or the mode value of the coordinate values as the wave source position. Good.

In the present embodiment, at least one of the N pieces of data is included in a plurality of sets. For example, the reception intensity data output from the receiver 20-A is included in the first set and the second set. On the other hand, in the conventional Newton method, when N pieces of received intensity data are divided into K sets of data groups, certain received intensity data belongs to one of the sets, but belongs to a plurality of sets. It never happened. According to the method of this embodiment, the accuracy of the position of the wave source can be ensured even if the number of receivers is reduced. Alternatively, if the number of receivers is the same as the conventional one, the accuracy of the position of the wave source can be improved.

For example, assume that provisional estimation is performed using three pieces of received intensity data per set, and the position of one wave source is estimated from the twenty provisional estimated positions. According to the conventional method, 60 receivers are required. However, according to the method of this embodiment, six receivers may be provided. According to the present embodiment, the cost of installing the receiver and the installation range can be greatly reduced.

Hereinafter, configuration examples of the positioning system, the positioning device, and the computer program will be described with reference to the accompanying drawings. However, more detailed explanation than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. The inventor provides the accompanying drawings and the following description in order for those skilled in the art to fully understand the present disclosure, and is not intended to limit the subject matter described in the claims. Absent. In the following description, the same or similar components are denoted by the same reference numerals.

FIG. 1 schematically shows a configuration of a positioning system 1 according to an exemplary embodiment of the present invention. The positioning system 1 includes a signal generator 10, a plurality of receivers 20-A, 20-B,..., 20-N (N: 4 or an integer greater than or equal to 5), and a positioning device 30. .

The positioning device 30 of the positioning system 1 estimates the position of the signal generator 10 using the signal wave output from the signal generator 10.

The signal generator 10 is an electronic circuit that generates a signal using electric power supplied from an internal battery or externally and outputs it as a signal wave. The signal generator 10 emits electromagnetic waves or sound waves as signal waves. In this specification, the signal generator 10 may be referred to as a “wave source”. In the present specification, the signal generator 10 is described as outputting an electromagnetic wave in the 2.4 GHz band conforming to the BLE standard.

The signal generator 10 can be built in an electronic device owned by a person when the positioning target is a person. Alternatively, when the positioning target is an object, the signal generator 10 may be attached to the object, or may be incorporated in the object.

The positioning system 1 estimates the position of the signal generator 10 in the space where the positioning system 1 is installed. The “space” mainly assumes a three-dimensional space in the present embodiment. In the figure, an X axis, a Y axis, and a Z axis are shown. However, the “space” may be a two-dimensional space. For example, when positioning a self-propelled vehicle traveling on the floor, the positioning system 1 may estimate the position of the signal generator 10 on a two-dimensional space that is the floor. As will be described later, when the positioning system 1 estimates the position of the two-dimensional space, it is sufficient that at least four receivers exist. When the positioning system 1 estimates the position in the three-dimensional space, it is sufficient that there are at least five receivers.

Each of the plurality of receivers 20-A, 20-B,..., 20-N includes an antenna device (not shown), and receives a signal wave output from a wave source using the antenna device. To do. The antenna device can receive electromagnetic waves that conform to the BLE standard described above. Each receiver outputs signal wave reception intensity data. In addition, since the structure of an antenna apparatus is well-known, description of a specific structure is abbreviate | omitted. When the signal generator 10 generates sound waves, each receiver can be a device having a microphone.

The positioning device 30 has an arithmetic circuit 31. The arithmetic circuit 31 receives the reception intensity data of the signal wave from each of the plurality of receivers 20-A, 20-B,..., 20-N, performs a predetermined calculation, and each coordinate component indicating the position of the wave source Is calculated. Details of the calculation will be described later.

FIG. 2 shows a first example of an environment where the positioning system 1 is introduced. In the example of FIG. 2, the positioning system 1 is constructed in a factory, a bookstore, or the like having shelves 22 and 23 on which objects are placed. The position of each of the plurality of receivers is indicated by “●”. The plurality of receivers are generally distributed. Note that FIG. 2 is an XY plan view, and the relationship in the z-axis direction is not shown.

In this embodiment, it is assumed that the plurality of receivers are installed at predetermined positions. When a certain reference position O is set as the origin and three axes (X axis, Y axis and Z axis) as shown in the figure are defined, the position of each receiver is determined by each value of the X axis, Y axis and Z axis. Can be represented. In the following, coordinates A receiver 20-A (x _a, y _a, z _a) is expressed as such, x _a, and each y _a and z _a "x-coordinate", "y coordinate,""zcoordinates" Sometimes called. In the receiver 20 -J illustrated on the drawing, the x coordinate is x _J , the y coordinate is y _J , and the z coordinate is z _J.

For the reasons described later, in this embodiment, it is assumed that the x coordinates of a plurality of receivers used for calculation do not all have the same value. In other words, the positioning device 30 performs calculation using a plurality of receivers having at least one different x coordinate. The same applies to the y coordinate and the z coordinate. Therefore, for example, for the z coordinate, a plurality of receivers having different heights are used.

FIG. 3 shows a second example of the environment where the positioning system 1 is introduced. As can be seen from the drawing, in FIG. 3, a plurality of receivers are provided together in some compartments R in the environment. Note that FIG. 3 is also an XY plan view, and the relationship in the z-axis direction is not shown. In the configuration of FIG. 3, a plurality of receiver units whose positions are adjusted and integrated so as to satisfy the above-described position conditions are manufactured in advance and fixed to a ceiling portion of the introduction environment of the positioning system 1. Is easily realized.

The positioning process according to the present embodiment can be used in any of the modes shown in FIGS.

Next, the positioning target in the positioning system 1 will be described with reference to FIGS.

The signal generator 10 may be provided in an object installed at a fixed position, or may be provided in an object whose position can change, for example, a self-propelled vehicle or a portable electronic device. Portable electronic devices are, for example, mobile phones, smartphones, and electronic tag devices.

FIG. 4 shows four shelves including shelves 22 and 23 in FIGS. Each shelf has a plurality of shelves 25 for placing objects. In the present embodiment, it is assumed that a plurality of shelves 25 may exist in the Y-axis direction and the Z-axis direction.

FIG. 5 shows the signal generator 10 attached to the product 24 a placed on the shelf 25. The signal wave output from the signal generator 10 is received by four or five or more receivers. FIG. 5 shows a state where the receivers 20-S and 20-T receive the signal waves output from the signal generator 10, respectively. The positioning system 1 can estimate the position where the product 24a is placed.

FIG. 6 shows the signal generator 10 mounted on a self-propelled vehicle 24b traveling between the shelves 22 and 23. This example also shows a state in which the receivers 20-S and 20-T are receiving signal waves output from the signal generator 10, respectively. The positioning system 1 can estimate the position of the self-propelled vehicle 24b in real time.

FIG. 7 shows the signal generator 10 mounted on a smartphone 24c of a shopper walking between shelves 22 and 23. This example also shows a state in which the receivers 20-S and 20-T are receiving signal waves output from the signal generator 10, respectively. The positioning system 1 can estimate the position of the shopper in real time.

5 to 7, only one signal generator 10 is shown, but a plurality of signal generators 10 may exist. The positioning system 1 can estimate the position of each signal generator 10 from identification information that uniquely identifies each signal generator 10 included in the received signal wave by performing processing in parallel.

Next, the configuration of the signal generator 10 and the positioning device 30 will be described.

FIG. 8 shows the hardware of the signal generator 10. The signal generator 10 includes an IC 11 for generating a high frequency signal, a storage device 12, and an antenna 14. The storage device 12 is a flash ROM, for example, and stores unique identification information 13 for each signal generator 10. The IC 11 periodically transmits identification information using the antenna 14.

FIG. 9 shows the hardware configuration of the positioning device 30.

The positioning device 30 includes a CPU 31, a memory 32, and a communication circuit 33, which are connected by an internal bus. The CPU 31 is an arithmetic circuit that estimates the position of each signal generator 10 and generates position information indicating the estimated position by processing described later. The memory 32 is a DRAM, for example, and is a work memory used in connection with the processing of the CPU 31.

The communication circuit 33 is a communication circuit having one or more communication connectors, for example. The communication connector includes an input interface 34a and an output interface 34b that outputs data of wave source coordinates. The input interface 34a and the output interface 34b may be integrated and mounted as one communication connector.

The input interface 34a is a so-called signal input terminal, and receives a high-frequency electric signal from each of the receivers 20-A to 20-N. The high-frequency electrical signal is a signal generated by converting electromagnetic waves (signal waves) received by each receiver.

The output interface 34b is a communication terminal that performs, for example, Ethernet (registered trademark) standard wired communication, and outputs data of the coordinates of the wave source. Instead of the data on the coordinates of the wave source, the output interface 34b may output a video signal obtained by imaging the coordinates of the wave source. At this time, the output interface 34b may be an image signal output terminal such as a DVI terminal. FIG. 9 shows an output interface 34 b connected to the display device 35.

Next, the positioning algorithm according to this embodiment will be described. In the following, an example in which nine receivers shown in FIG. 3 are used will be described.

FIG. 10, FIG. 11 and FIG. 12 each show three receivers that output three received intensity data used for three-point positioning. The CPU 31 temporarily estimates the position of the wave source P using the three received intensity data output from the three receivers shown as a set.

FIG. 10 shows the receivers 20-A, 20-B, and 20-C. FIG. 11 shows the receivers 20-A, 20-D and 20-G. In the figure, the position A of the receiver 20-A is represented as (x _a , y _a , z _a ) or the like. Further, the distance from the wave source position P to the receiver 20-A represents the like r _a. The position P of the wave source (signal generator 10) to be measured is represented as (x, y, z).

10 and 11 show different sets. However, the receiver 20-A is redundantly included in both sets. As described at the beginning, in this embodiment, a certain receiver (more precisely, reception intensity data output by the receiver) is allowed to be included in a plurality of sets. In the present embodiment, it is allowed that a receiver set that does not overlap with the receiver combinations shown in FIGS. 10 and 11 exists. FIG. 11 shows receivers 20-E, 20-F, and 20-I that are not included in any of the sets shown in FIGS.

Hereinafter, the principle of three-point positioning will be described with reference to FIG. FIG. 13 is a generalized view of FIG.

FIG. 13 shows three receivers 20-A, 20-B and 20-C located at different distances from the wave source P. From these positional relationships, three functions f _a , f _b, and f _c satisfying Equation 1 below are established.

These are ternary simultaneous nonlinear equations. The ternary simultaneous nonlinear equations can be solved using the Newton method of the following formula 2.

Here, X _k is a coordinate matrix indicating the position of the wave source (signal generator 10) after the calculation is repeated k times, and is specifically expressed by the following equation (3).

Further, J (x _k ) in Equation 2 is a Jacobian matrix, and is specifically shown in Equation 4 below.

Based on the above equations, X _{k + 1} can be obtained as shown in Equation 5 below.

Now, pay attention to the column vector of the second term on the right side of Equation 5 (column vector F (x _k ) in Equation 3). As shown in Equation 1, each element f _a , f _b and f _c constituting the column vector F has a square of the distance from the wave source position P to each receiver 20-A, 20-B and 20-C. Terms (r _a ² , r _b ² , r _c ² ) are included. Since the position of the wave source P is not obtained, these values cannot be obtained directly.

Therefore, in a positioning system using the BLE standard, the received signal level of the signal from the signal generator 10 received by each receiver is used. Specifically, the signal generator 10 and the receivers 20-A, 20-B and 20-C are placed at a distance of 1 m in advance, and the reception power value Po at that time is acquired in advance. Thereafter, when a signal is received from the signal generator 10, distance information between the signal generator and the receiver at the time of measurement is obtained using the received signal level Pi at that time. Specifically, the distance information r _i ² at the time of measurement can be obtained by Po / Pi. In the memory 32, reference signal power information Po, which is reception intensity data at a distance of 1 m, is held in advance. If the effective area of each receiving antenna of the receivers 20-A, 20-B and 20-C and the gain of each receiving antenna are equal to each other, that is, have the same reception performance, the signal generator 10 And one receiver may be placed at a distance of 1 m, and the received power value P_o at that time may be acquired in advance.

By repeating the above processing until convergence, the left side of Equation 5, that is, the position (x, y, z) of the wave source can be estimated. The inventor of the present application has confirmed by simulation that when the calculation is repeated about six times from an appropriately set initial value (x ₀ , y ₀ , z ₀ ), the calculation converges to an expected position.

The CPU 31 of the positioning device 30 performs a calculation according to the above-described principle, and performs a temporary estimation of the position of the wave source P using each set of received intensity data. Then, one position is estimated as the position of the wave source P from a plurality of temporary estimation results.

Hereinafter, the operation of the CPU 31 will be described with reference to FIG. 14, FIG. 15 and FIG.

FIG. 14 mainly shows the configuration of the processing block of the CPU 31.

The CPU 31 functions as a combination pattern generator 41, three-point positioning processing blocks 42-1 to 42-K, and an average value calculator 43. In FIG. 14, a plurality of components are shown to exist, but these merely mean a unit of processing. The number of components shown need not be included. In the present embodiment, the CPU 31 operates in accordance with a computer program that performs processing according to the flowchart shown in FIG. The CPU 31 operates as a combination pattern generator 41 depending on time according to instructions of the computer program, operates as each of the three-point positioning processing blocks 42-1 to 42-K, and operates as an average value calculator 43. An arrow from the processing block to the processing block means that the data is used for the next calculation.

However, at least one of the combination pattern generator 41, the three-point positioning processing blocks 42-1 to 42-K, and the average value calculator 43 may be realized by hardware. For example, by using an FPGA (Field-programmable gate array), the combination pattern generator 41, the three-point positioning processing blocks 42-1 to 42-K, and the average value calculator 43 are mounted on one integrated circuit. Is possible. Preferably, the processing cores corresponding to each of the three-point positioning processing blocks 42-1 to 42-K are implemented as hardware, and parallel processing is performed, so that calculation can be performed at a very high speed.

The received intensity data output from each of the N receivers is received via the communication circuit 33 (FIG. 9) and stored in the memory 32.

The combination pattern generator 41 of the CPU 31 extracts K sets of three sets of data from the received N pieces of data. The number of sets K is the number of combinations, and there are _N C ₃ ways. For example, when N = 9, 84 data sets are obtained. The combination pattern generator 41 reads out a data group for each combination and inputs it to each of the three-point positioning blocks 42-1 to 42-K. Hereinafter, the three-point positioning blocks 42-1 to 42-K are collectively referred to as “three-point positioning block 42”.

Each of the three-point positioning blocks 42 provisionally estimates the position of the wave source P for each set using the received three data. Each position of the temporarily estimated wave source P is sent to the average value calculator 43. The output (provisional estimated value) from the three-point positioning block includes each of the x coordinate value, the y coordinate value, and the z coordinate value.

The average value calculator 43 calculates an average value for each x coordinate, each y coordinate, and each z coordinate using each temporary estimated value output from the three-point positioning block. Each obtained average value is output as the estimated position of the wave source P.

The average value calculator 43 may estimate the median value or mode value of each coordinate value as the position of the wave source instead of the average value of each coordinate value.

The above-described processing of the average value calculator 43 can be said to be processing for obtaining an estimated position of the wave source P by spatial average calculation using a plurality of receivers existing at different positions. The average value calculator 43 may output the estimated position of the wave source P by time average calculation. Specifically, the average value calculator 43 calculates the average value for each x-coordinate, y-coordinate, and z-coordinate, and then performs the same processing using the next received intensity data obtained from each receiver. The average value for each x coordinate, y coordinate, and z coordinate at the next time is calculated. The plurality of estimated positions of the wave source P obtained based on the received intensity data at different times are further averaged, and the obtained result is output as the estimated position of the wave source P. This makes it possible to estimate the position of the wave source P based on the time average.

FIG. 15 shows a configuration of a three-point positioning processing block 42 that performs temporary estimation.

The three-point positioning processing block 42 includes a power / distance converter 45, a function calculator 46, an inverse matrix calculator 47, a vector multiplier 48, and a convergence determiner 49. Similarly to FIG. 14, the CPU 31 may be operated as each of these components, or a part or all of the CPU 31 may be provided and operated as hardware using an FPGA or the like.

The power / distance converter 45 receives, from the memory 32, a set of three pieces of received intensity data and reference signal power information Po that is received intensity data at a distance of 1 m. As an example, in FIG. 15, the power / distance converter 45 receives the received intensity data Pa, Pb and Pc of the receivers 20-A, 20-B and 20-C.

The power / distance converter 45 calculates Po / Pi for each of the three reception intensity data Pi. The obtained value corresponds to the square of the distance between each receiver and the wave source P (r _i ² ). In FIG. 15, the power / distance converter 45 represents the square of the distance (r _a ² , r _b ² , r _c ² ) between the wave source P and each of the receivers 20 -A, 20 -B, and 20 -C. The value is output.

The function calculator 46 obtains each function shown in Equation 1.

The inverse matrix calculator 47 obtains the inverse matrix shown in Equation 5. Inverse matrix computation methods are known and can be calculated using, for example, a sweep out method. A library of computer programs that outputs the inverse matrix Q ^-1 when the matrix Q is input is also known and easily available. The CPU 31 may be operated as the inverse matrix calculator 47 using such a library program.

The vector multiplier 48 performs the operation of the second term on the right side of Equation 5 and outputs the result to the convergence determiner 49.

The convergence determiner 49 determines whether the result output from the vector multiplier 48 satisfies a predetermined convergence condition. For example, the convergence determination unit 49 may determine that the convergence has occurred when the amount of change in each of the x coordinate, the y coordinate, and the z coordinate is less than a predetermined value. This process corresponds to the process of the following formula 6 obtained by modifying the formula 5 described above.

When it is determined that the convergence condition is not satisfied, the convergence determination unit 49 performs the calculation of the number of repetitions 5 until convergence using the obtained values (x _k , y _k , z _k ).

When it is determined that the convergence condition is satisfied, the convergence determination unit 49 outputs the temporary estimated position (x, y, z) of the wave source P. Note that the convergence determination unit 49 may determine that the convergence has occurred when a predetermined number of operations have been performed.

FIG. 16 is a flowchart showing a processing procedure of the positioning device 30. Of the processing in FIG. 16, step S2 and subsequent steps correspond to the processing of the CPU 31.

The positioning device 30 receives a value of reception intensity (reception intensity data) from each of the receivers 20-A to 20-N (step S1).

The combination pattern generator 41 extracts K sets of three data sets selected from the N received intensity data (step S2). Each of the three-point positioning processing blocks 42-1 to 42-K performs provisional estimation of the position of the wave source P using the extracted data group of each set (step S3). As a result, K temporary estimation results are obtained.

The average value calculator 43 averages the K preliminary estimation results to estimate the position of the wave source P (step S4), and outputs the obtained result as the position of the wave source P.

By the above processing, the position of the signal generator 10 that is a wave source can be estimated.

(Modification)
In the above description, the signal generator and the receiver are placed at a distance of 1 m in advance, and the received power value Po at that time is acquired in advance. This is because the information on the distance between the signal generator and each receiver is usually not known.

However, it may be difficult in practice to obtain the reception power value Po in advance. For example, assume that a positioning system is used to estimate the position of a shopper who moves within a facility. When an electronic device (for example, a smartphone) owned by a shopper is used as a signal generator, it is practically difficult to obtain all the electronic devices at a position of 1 m of the receiver and obtain a reception power value in advance.

In the case of a positioning system installed in a facility (for example, a factory) where the type and number of signal generators to be used are determined in advance, the received power value at the 1 m position described above can be obtained in advance. There is. However, the transmission output of the signal generator at the time of preliminary measurement may be different from the transmission output of the signal generator at the time of positioning due to the remaining amount of the battery. For the receiver as well, there may be a case where the measurement status differs between prior measurement and positioning.

Therefore, as a result of diligent study, the inventor of the present application has constructed an algorithm that enables positioning without obtaining a reception power value at a position of 1 m in advance.

The positioning algorithm described below can be used in place of the above-described three-point positioning algorithm using the Newton method. That is, the configuration of FIG. 18 to be described next can be used in place of the configuration of each three-point positioning block 42 of FIGS. 13 and 14.

In this modification, the signal wave output from the wave source is received by each of four or five or more receivers. The wave source is a signal generator that outputs signal waves such as electromagnetic waves and sound waves.

Each receiver receives the signal wave output from the wave source and outputs data indicating the received intensity of the signal wave. The arithmetic circuit receives data indicating the reception intensity of the signal wave from each of the plurality of receivers, performs a predetermined calculation, and calculates each coordinate component of the position of the wave source. This calculation includes a calculation for obtaining a predetermined inverse matrix, but is different from the inverse matrix calculation of the partial differential matrix used in the Newton method.

Now, two vectors p and s are defined as follows.

Vector p: a vector including each coordinate component of the position of the wave source from a predetermined reference position as each component vector s: a vector in which the squares of the distances from the predetermined reference position to each receiver are arranged

The predetermined reference position is an arbitrary position in the space where the positioning system is installed, and can be defined as the position of the origin. The “position” may be a position in a two-dimensional space or a position in a three-dimensional space.

The arithmetic circuit
Matrix Q vector p = vector s
The inverse matrix Q ⁻¹ of the four-dimensional or five-dimensional regular square matrix Q satisfying the relational expression is calculated, the calculated inverse matrix Q ^{−1 is applied} to the vector s, and each position of the wave source included in the vector p is calculated. A coordinate component is calculated. The calculated coordinate component is output to the average value calculator 43 as one temporary estimated value shown in FIG.

Note that the condition that the matrix Q is a regular square matrix can be easily satisfied by adjusting the position of each receiver, as will be described in detail later.

Hereinafter, the positioning algorithm according to this embodiment completed by the present inventor will be described.

In the following, five receivers are used for positioning in a three-dimensional space. In the case of positioning in a two-dimensional space, there may be four receivers. As described above, the position A of the receiver 20-A is represented as (x _a , y _a , z _a ) or the like. Further, the distance from the wave source position P to the receiver 20-A represents the like r _a. The position P of the wave source (signal generator 10) to be measured is represented as (x, y, z).

FIG. 17 shows the positional relationship between the wave source position P and each receiver. FIG. 17 shows the wave source position P and the positions A to D of each receiver. In FIG. 17, the origin O is shown as the reference position. The origin O can be arbitrarily determined. The position of each receiver is determined based on the position (0, 0, 0) of the origin O.

The following relationship is established between the wave source position P and the position A of the receiver 20-A.

Similarly, the following relationship holds between the wave source position P and the positions of other receivers.

Here, parameters β _b to β _e are introduced. The parameter β _b is the square of the magnitude of the distance r _b from the wave source position P to the receiver 20-B with respect to the distance r _a from the wave source position P to the receiver 20-A. Therefore, it is expressed as follows.
(Equation 12)
β _b = (r _b / r _a ) ²

Similarly, beta _c, also beta _d and beta _e, by using the distance r _a from the wave source position P to the receiver 20-A, the distance from the wave source position P to each receiver, collectively represented as follows be able to.
(Equation 13)
β _c = (r _c / r _a ) ²
β _d = (r _d / r _a ) ²
β _e = (r _e / r _a ) ²

When Equations 8 and 11 are transformed using Equations 12 and 13, the following Equation 14 is obtained.

When the formulas 7 and 14 are expanded and transformed, the following formula is obtained.

Now, the unknown number included in Equation 15 is replaced as follows.

The above-described variable replacement is an operation of changing a second-order term (nonlinear term or nonlinear component) to a first-order term (linear term or linear component). That is, it corresponds to linearizing a nonlinear equation.

Then, Formula 15 can be expressed as follows using a matrix.

Expression 17 can be expressed as follows using the matrix Q and the column vectors p and s.
(Equation 18)
Q ・ p = s

Among the elements included in the vector p, x, y, and z are unknown numbers representing the position of the wave source P. When the inverse matrix of the matrix Q is expressed as Q ⁻¹ , the vector p can be obtained by the following equation.
(Equation 19)
p = Q ^-1 · s

Equation 19 is specifically expressed as follows.

As a condition for satisfying Equations 19 and 20, it is necessary that an inverse matrix of the matrix Q exists, in other words, the matrix Q is a regular square matrix. The condition is that the determinant is not zero. In order to satisfy the condition, (i) there is no integer multiple relationship between one row of the matrix Q and another row, and (ii) between one column of the matrix Q and another column It is necessary that there is no integer multiple relationship. As shown in Expression 20, when attention is paid to the row of the matrix Q, the above relationship (i) is clearly not satisfied. If the above relationship is satisfied, the positions of the five receivers need to be at least the same, but such an arrangement is not possible.

Therefore, consider the relationship of the columns of the matrix Q. If all the x, y, or z coordinates of the five receivers match, the above relationship (ii) is satisfied. Therefore, when selecting five receivers, a set of receivers that do not satisfy such a condition may not be adopted. For example, for the z coordinate, five receivers with different heights are selected. The relationship between the x coordinate and the y coordinate is the same.

Next, the handling of the parameters β _b to β _e when obtaining the inverse matrix of the matrix Q will be described. The parameters β _b to β _e can be obtained from the reception intensity of the receivers 20-A to 20-E.

First, according to Friis' transmission formula, the following equation is known to hold.
(Equation 21)
Pr = (λ / 4πr) ² · Pt · Gt · Gr

Here, Pr is the received power, λ is a constant, r is the distance between the transmitter and the receiver, Pt is the transmitted power of the signal generator 10, Gt is the gain of the transmitting antenna 14 (FIG. 8) of the signal generator 10, Gr Is the gain of the receiving antenna. Here, Pt and Gt have the same value because they are a common wave source. The gain Gr of the receiving antenna can be assumed to be the same value by making it common to all the receivers 20-A to 20-E.

The relationship between each of the receivers 20-A to 20-E and the wave source can be expressed as follows. The reception strengths of the receivers 20-A to 20-E are represented as Pa to Pe.
(Equation 22)
Pa = (λ / 4πr _a ) ² · Pt · Gt · Gr
Pb = (λ / 4πr _b ) ² · Pt · Gt · Gr
Pc = (λ / 4πr _c ) ² · Pt · Gt · Gr
Pd = (λ / 4πr _d ) ² · Pt · Gt · Gr
Pe = (λ / 4πr _e ) ² · Pt · Gt · Gr

Using this formula and the definition formulas of the parameters β _b to β _e , the following Expression 23 is obtained.
(Equation 23)
β _b = Pa / Pb
β _c = Pa / Pc
β _d = Pa / Pd
β _e = Pa / P _e

As is clear from Equation 23, β _b to β _e can be specifically obtained using the reception strengths of the receivers 20-A to 20-E.

The right side of Equation 17 is the square of the distance from the origin O, which is the reference position, to each receiver. The position of each receiver is predetermined. Therefore, the square of the distance from the origin O can also be acquired in advance. The vector on the right side of Expression 17 is included in Expression 20.

As described above, the inverse matrix Q ⁻¹ of the matrix Q shown on the right side of Equation 20 can be obtained by calculation. Further, each component of the vector s in which the squares of the distances from the origin position to the respective receivers are arranged can be obtained in advance. Thereby, the components x, y, and z on the left side of Equation 20, that is, the position (x, y, z) of the wave source can be estimated. The obtained position (x, y, z) can be used as one temporary estimated value in the example shown in FIG.

The CPU 31 of the positioning device 30 executes a calculation according to the above principle. Hereinafter, the operation of the CPU 31 will be described with reference to FIGS. 18 and 19.

FIG. 18 shows the configuration of the 5-point positioning block 50. FIG. 19 is a flowchart showing a processing procedure of the CPU 31 functioning as the five-point positioning block 50.

The 5-point positioning block 50 functions as a parameter calculator 51, an inverse matrix calculator 52, and a vector multiplier 53. In FIG. 18, it is shown as if there are three components, but it actually means a unit of processing. In the present embodiment, the CPU 31 functioning as the five-point positioning block 50 operates according to a computer program that performs processing according to the flowchart shown in FIG. The CPU 31 operates as a parameter calculator 51, operates as an inverse matrix calculator 52, and operates as a vector multiplier 53 depending on time according to instructions of the computer program. An arrow from the processing block to the processing block means that the data is used for the next calculation.

However, at least one of the parameter calculator 51, the inverse matrix calculator 52, and the vector multiplier 53 may be realized by hardware. For example, by using an FPGA (Field-programmable gate array), the parameter calculator 51, the inverse matrix calculator 52, and the vector multiplier 53 can be mounted on one integrated circuit.

Hereinafter, for convenience of explanation, the parameter calculator 51, the inverse matrix calculator 52, and the vector multiplier 53 will be described as independent components.

The parameter calculator 51 receives the value of the reception intensity from each of the receivers 20-A to 20-E, and calculates the parameters β _b to β _e by performing the calculation shown in Equation 23 (step S11). Each calculated parameter is sent to the inverse matrix calculator 52.

The inverse matrix calculator 52 receives the parameters β _b to β _e from the parameter calculator 51. The inverse matrix calculator 52 reads data indicating the position coordinates of each receiver stored in the memory 32 (step S12). Then, the inverse matrix calculator 52 calculates an inverse matrix of the matrix Q using the parameters β _b to β _e and data indicating the position coordinates of each receiver (step S13). Inverse matrix computation methods are known and can be calculated using, for example, a sweep out method. A library of computer programs that outputs the inverse matrix Q ^-1 when the matrix Q is input is also known and easily available. The CPU 31 may be operated as the inverse matrix calculator 52 using such a library program.

The vector multiplier 53 receives the inverse matrix Q ⁻¹ calculated by the inverse matrix calculator 52 and data indicating the position coordinates of each receiver stored in the memory 32. The latter is used to obtain a vector s in which the squares of the distances from the origin position to each receiver are arranged. Based on the received data, the vector multiplier 53 performs an operation Q ⁻¹ · s (step S14). Thereby, the vector p on the left side of Equation 20 can be obtained. The vector multiplier 53 outputs x, y, z, which are the components of the obtained vector p, as the position of the wave source (step S15).

By the above processing, the position of the signal generator 10 that is a wave source can be estimated.

As a result of the operation shown in Equation 16 above, the number of linear terms increased as a result. That is, by linearizing two nonlinear terms, the unknowns increased by two in addition to x, y, and z indicating the position of the wave source. In order to obtain five unknowns, five simultaneous equations are required. This is the reason why a matrix Q of 5 rows and 5 columns is required using signals from five receivers. In order to obtain the inverse matrix, the present inventor increased the number of receivers to compensate for the decrease in the rank of the matrix.

By linearizing the algorithm, multiple solutions can be avoided and it is not necessary to perform repetitive computations compared to the case of using the Newton method, so that the load on hardware and software processing can be reduced. The BLE positioning system can be introduced relatively easily. Due to such characteristics, it is required to reduce the cost of introduction. Since the linear measurement process determines the output uniquely with respect to the input, it can be tabulated and contributes to the cost reduction of the system.

“Tableization” refers to preparing a table in which a set of β _b , β _c , β _d , and β _e measured in advance is associated with a set of x, y, and z estimated from them. . When reception intensity data is actually obtained and a set of β _b , β _c , β _d , and β _e is determined, a matching set is searched with reference to a table. If there is a matching set in the table, the associated x, y, z set is read and output. Since a matrix operation or the like is not necessary, the result can be output at a very high speed. Furthermore, the load on the CPU 31 can be greatly suppressed. As the number of entries in the table increases, there is a higher possibility that a pair that matches the actually measured pair of β _b , β _c , β _d , and β _e exists on the table.

It is very easy to increase the number of entries in the table. In the environment where the positioning system 1 is introduced, each receiver receives a signal wave and obtains a set of β _b , β _c , β _d , and β _e while changing the position of the signal generator 10 as a wave source. This is because the set of wave source positions x, y, and z should be estimated. If a table having a sufficiently high search hit rate is provided, information indicating the position of the wave source can be output at a sufficiently high speed even if a CPU having a relatively low processing capability is employed.

As can be inferred from the above explanation, when estimating the position of the two-dimensional space, it is only necessary to obtain the received intensity data from the four receivers. The matrix Q and vectors p and s necessary for estimating the position in the two-dimensional space are as follows.

Note that the conditions regarding the position of the receiver for the existence of the inverse matrix of the matrix Q are the same.

After estimating the position of the signal generator 10, the positioning system 1 may guide the self-propelled vehicle 24b and / or the smartphone 24c to a predetermined position using, for example, a guidance device (not shown). The guidance device can notify the position of the destination and guide the person who owns the self-propelled vehicle 24b or the smartphone 24c to the position. At this time, the process of estimating the position of the signal generator 10 can be performed in real time or intermittently to perform appropriate guidance.

In the above description, the reception intensity data from four receivers is used to estimate the position in the two-dimensional space. However, the reception intensity data from five or more receivers is used. Also good. In addition, although it has been described that reception intensity data from five receivers is used to estimate a position in a three-dimensional space, reception intensity data from six or more receivers may be used.

The guidance system of the present disclosure can be used for estimating the position of a moving body that moves indoors or outdoors. Moreover, it can be used for control of the position of the moving body using the positioning result.

DESCRIPTION OF SYMBOLS 1 Positioning system 10 Signal generator 20-A, 20-B, ..., 20-N Receiver 30 Positioning device 31 CPU (arithmetic circuit)
32 memory 33 communication circuit 34a input interface 34b output interface 41 combination pattern generator 42-1 to 42-K 3-point positioning processing block 43 average value calculator

Claims (12)

1. A plurality of receivers (N is an integer of 4 or more) each receiving a signal wave output from a wave source, each receiving a signal wave output from the wave source and receiving the signal wave A plurality of receivers that output data indicating the intensity;
   An arithmetic circuit that receives data indicating the reception intensity of the signal wave from each of the plurality of receivers and estimates the position of the wave source using the received N pieces of data; and
   The arithmetic circuit is:
   For K sets of data groups (K: an integer of 2 or more) each including 3 or more data selected from the received N data, each set of 3 or more data is used to Temporarily estimate the position for each pair,
   Estimating the position of the wave source based on the position of two or more of the temporarily estimated wave sources;
   The positioning system, wherein at least one of the N pieces of data is included in a plurality of sets.
2. The positioning system according to claim 1, wherein the arithmetic circuit generates K sets of data groups each including three pieces of data, and temporarily estimates the position of the wave source for each set by a three-point positioning method.
3. The positioning system according to claim 2, wherein the arithmetic circuit generates a data group of _N C ₃ or less.
4. The positioning system according to any one of claims 1 to 3, wherein the arithmetic circuit tentatively estimates the position of the wave source for each set from three sets of data by Newton's method.
5. The arithmetic circuit is:
   From the received N pieces of data, generate K sets of data groups (K: an integer of 2 or more) each including 4 or 5 or more data,
   Matrix Q vector p = vector s
   (However, vector p: a vector including each coordinate component of the position of the wave source from a predetermined reference position as a component, vector s: a vector in which squares of distances from the predetermined reference position to the respective receivers are arranged)
   The inverse matrix Q ⁻¹ of the four-dimensional or five-dimensional regular square matrix Q that satisfies the relational expression is calculated, and the calculated inverse matrix Q ^{−1 is applied} to the vector s, so that the wave source included in the vector p Each coordinate component of the position of
   The first relational expression that the sum of the squares of the difference between each coordinate component of each receiver position and each coordinate component of the wave source position is equal to the square of the distance between each receiver and the wave source:
   The sum of the quadratic term including each coordinate component of the position of the wave source, the primary term, and the term of the square of the distance between each receiver and the wave source is from a predetermined reference position to each receiver. Transformed into a second relational expression equal to the square of the distance of
   The vector p is defined to further include a component obtained by replacing the quadratic term with a first linear component, and a component obtained by replacing a square term of a distance between a predetermined receiver and the wave source with a second linear component. When
   The arithmetic circuit includes a value of a ratio between a reception intensity of the predetermined receiver and each reception intensity of other receivers as a row or column component multiplied by the second linear component, and the inverse of the matrix Q The positioning system according to claim 1, wherein the positioning system calculates a matrix Q ⁻¹ .
6. The positioning system according to any one of claims 1 to 5, wherein the arithmetic circuit performs an arithmetic operation for averaging the temporarily estimated results to estimate the position of the wave source.
7. The positioning system according to claim 6, wherein the arithmetic circuit estimates a position of the wave source by performing a spatial average calculation of the positions of the two or more wave sources temporarily estimated.
8. The positioning system according to any one of claims 1 to 5, wherein the arithmetic circuit estimates one of a median value and a mode value of two or more temporarily estimated wave source positions as the wave source position.
9. The positioning system according to any one of claims 1 to 8, wherein the wave source emits an electromagnetic wave or a sound wave as the signal wave.
10. 10. The positioning system according to claim 1, further comprising an interface that outputs coordinates of the wave source calculated by the arithmetic circuit.
11. A positioning device used in a positioning system,
    The positioning system includes a plurality of receivers (N is an integer of 4 or more) that respectively receive signal waves output from a wave source, each receiving a signal wave output from a wave source. A plurality of receivers for outputting data indicating the reception intensity of the signal wave;
    The positioning device is
    An input terminal for receiving data indicating the reception intensity of the signal wave from each of the plurality of receivers;
    An arithmetic circuit that receives data indicating the reception intensity of the signal wave from each of the plurality of receivers and estimates the position of the wave source using the received N pieces of data, and the position of the wave source calculated by the arithmetic circuit An output terminal for outputting data of each coordinate component of
    The arithmetic circuit is:
    For K sets of data groups (K: an integer of 2 or more) each including 3 or more data selected from the received N data, each set of 3 or more data is used to Temporarily estimate the position for each pair,
    Estimating the position of the wave source based on the position of two or more of the temporarily estimated wave sources;
    A positioning device, wherein at least one of the N pieces of data is included in a plurality of sets.
12. A computer program executed by a computer provided in a positioning device of a positioning system,
    The positioning system includes a plurality of receivers (N is an integer of 4 or more) that respectively receive signal waves output from a wave source, each receiving a signal wave output from a wave source. A plurality of receivers for outputting data indicating the reception intensity of the signal wave;
    The computer program is for the computer.
    Reading data indicating the received intensity of the signal wave obtained from each of the plurality of receivers;
    Estimating the position of the wave source using the read N pieces of data;
    Outputting the data of each coordinate component of the position of the wave source calculated by the arithmetic circuit; and
    The estimating step includes:
    For K sets of data groups (K: an integer of 2 or more) each including 3 or more data selected from the received N data, each set of 3 or more data is used to Temporarily estimate the position for each pair,
    Estimating the position of the wave source based on the position of two or more of the temporarily estimated wave sources;
    A computer program, wherein at least one of the N pieces of data is redundantly included in a plurality of sets.

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