WO2018180461A1

WO2018180461A1 - Positioning system, positioning device, and computer program

Info

Publication number: WO2018180461A1
Application number: PCT/JP2018/009702
Authority: WO
Inventors: 修一吉川
Original assignee: 日本電産株式会社; Ｋｐｎｅｔｗｏｒｋｓ株式会社
Priority date: 2017-03-28
Filing date: 2018-03-13
Publication date: 2018-10-04
Also published as: JPWO2018180461A1

Abstract

This positioning system (1) is provided with a plurality of receivers (20-A to 20-N, where N is 4 or an integer greater than or equal to 5) and a computation circuit (31). The computation circuit calculates the inverse matrix of a regular square matrix Q satisfying the relational expression Q∙p = s (where p is a vector including, as components, each coordinate component of a wave source position from a reference position and s is a vector arrived at by listing the differences between the squares of the distances from the reference position to each receiver and the squares of distance parameters for the receivers) from data indicating the time waveforms of the incident signal waves from the receivers and calculates each wave source coordinate component in vector p by causing the reverse matrix to act on the vector s. Q and p include variables arrived at by replacing a nonlinear term with a linear term. The computation circuit determines the inverse matrix of the matrix Q, which includes, as a row or column component to be multiplied by a reference distance term component, distance parameter terms for each receiver that are the products of the signal wave propagation speed and the time shift amounts for each receiver that maximize the correlation of the output time waveforms of each receiver and a reference receiver (20-A).

Description

Positioning system, positioning device and computer program

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

Japanese Patent Application Laid-Open No. 2012-198066 and Japanese Patent Application Laid-Open No. 11-160409 disclose position detection devices that detect the position of an object.

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 Newton's method, it is necessary to judge convergence to an appropriate value, and it may converge to another solution that is not expected. In addition, there are problems such as a heavy burden on hardware and software.

One non-limiting exemplary embodiment of the present application provides a positioning system that uses a positioning algorithm different from the Newton method.

According to an exemplary embodiment of the present disclosure, the positioning system is a plurality of five or more receivers, each receiving and receiving an incident signal wave including a signal wave output from a wave source. A plurality of receivers that output time waveform data of the incident signal wave, and the time waveform data received from each of the plurality of receivers, matrix Q · vector p = vector s (where vector p: A vector including each coordinate component of the position of the wave source from the reference position as a component, vector s: the difference between the square of the distance from the reference position to each receiver and the square of the distance parameter of each receiver is arranged The inverse matrix Q ⁻¹ of at least a five-dimensional regular square matrix Q that satisfies the relational expression (vector) is calculated, and the calculated inverse matrix Q ^{−1 is applied} to the vector s to be included in the vector p. Location of the wave source An arithmetic circuit for calculating each coordinate component; and a distance parameter of each receiver; a distance from a position of the wave source to a reference receiver of the plurality of receivers; and a plurality of receptions from the position of the wave source. And 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 the difference between each receiver and the wave source. The first relational expression that is equal to the square of the distance is given by the sum of the squares of the differences between the coordinate components at the positions of the receivers and the coordinate components at the positions of the wave sources. It is transformed into a second relational expression that is equal to the square of the sum of the reference distance that is the distance and the distance parameter of each receiver, and further includes a second-order term and a first-order term including each coordinate component of the position of the wave source. , The square of the reference distance, and the reference distance and each receiving The sum of the product term and the distance parameter of the machine is equal to the difference between the square of the distance from the reference position to each receiver and the square of the distance parameter of each receiver. When the vector p is defined to further include a component obtained by replacing the difference between the quadratic term and the square term of the reference distance with a linear component, and a component of the reference distance term, The arithmetic circuit shifts the time waveform data output from each receiver along the time axis for each receiver, and correlates with the time waveform data output from the reference receiver. Calculating a time shift amount that maximizes the correlation, and calculating a product of the determined time shift amount and the propagation speed of the signal wave output from the wave source as a distance parameter of each receiver; Distance of each receiver An inverse matrix Q ⁻¹ of the matrix Q is obtained that includes the separation parameter term as a row or column component to be multiplied by the component of the reference distance term.

According to an exemplary embodiment of the present disclosure, in the algorithm for estimating the position of the wave source, the nonlinear term included in the calculation is linearized. As a result, compared to the case of using the Newton method, multiple solutions can be avoided, and it is not necessary to perform repeated calculations. Therefore, the load on hardware and software processing can be reduced.

FIG. 1 is a diagram schematically illustrating a configuration of a positioning system 1 according to an exemplary embodiment of the present disclosure. 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 a positional relationship between the wave source position P and each receiver. FIG. 11 shows the time t _k (k: a, b, c, d, when the signal wave output from the wave source position P reaches each receiver 20-K (K: A, B, C, D, E). It is a wave form diagram which shows e) typically. FIG. 12 is a diagram schematically illustrating an example of a time waveform of a signal (output signal) output from each receiver 20-K. FIG. 13 is a diagram illustrating a configuration of a processing block of the CPU 31. FIG. 14 is a flowchart showing the processing procedure of the CPU 31.

As described above, a positioning system that uses Newton's method for a three-point positioning algorithm may not converge to an appropriate solution, and may have another problem. That is, it is a method for acquiring information on each distance between the signal generator and each receiver.

Information on each distance between the signal generator and each receiver is usually not known. Since distance information cannot be obtained directly, the BLE positioning system uses the received signal level of the signal from the signal generator received by each receiver. Specifically, the signal generator and the receiver are placed at a distance of 1 m in advance, and the received power value P_o at that time is acquired in advance. Thereafter, when a signal is received from the signal generator, distance information between the signal generator and the receiver at the time of measurement is obtained using the received signal level P_i at that time. Specifically, the distance information (r_i) ² = P_o / P_i at the time of measurement can be obtained.

However, a plurality of problems are included in the above processing. First, it may be difficult in practice to obtain the reception power value P_o in advance. For example, assume that a positioning system is used to estimate the position of a shopper who moves within a facility. If an electronic device (for example, a smartphone) owned by a shopper is used as a signal generator, it is not realistic 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.

Also, a method of obtaining each distance between the signal generator and each receiver using a time (Time Of Flight; TOF) until the signal transmitted from the signal generator reaches each receiver is conceivable. However, in order to obtain the TOF, it is necessary to accurately know the time when the signal generator transmits the signal. In other words, a mechanism for accurately transmitting the time at which the signal generator transmits a signal to each receiver is required. Furthermore, the signal generator and each receiver need to operate with a completely synchronized clock, and a mechanism for that purpose is also required.

The above problems all cause positioning errors.

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

Hereinafter, configuration examples of the positioning system, the positioning device, and the computer program 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 illustrates a configuration of a positioning system 1 according to an exemplary embodiment of the present disclosure. 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.

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 waveform data of the received signal wave. The waveform data indicates the magnitude of the received intensity of the signal wave. Output received 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 (CPU) 31. The arithmetic circuit 31 receives the waveform data of the signal wave from each of the plurality of receivers 20-A, 20-B,..., 20-N, performs a predetermined calculation, and obtains each coordinate component indicating the position of the wave source. calculate. 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. However, in actuality, the position of each receiver can be expressed using coordinates in the height direction (z-axis direction).

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 an origin and three axes (X axis, Y axis, and Z axis) are defined, the position of each receiver can be represented by each value of the X axis, Y axis, and Z axis. 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. That is, at least one y coordinate of the plurality of receivers is different, and at least one z coordinate of the plurality of receivers is also different.

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, but in practice, the position of each receiver can be expressed using coordinates in the height direction (z-axis direction). 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 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. According to the calculation described later, 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. However, as will be described in detail later, in order to estimate the position of each signal generator 10, it is necessary to identify the waveform of the signal wave output from each signal generator 10. Therefore, each signal generator 10 needs to radiate signal waves having different waveforms. 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 a hardware configuration 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 an input terminal that receives high-frequency electrical signals 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 completed by the present inventors will be described.

In this embodiment, five receivers are used. 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. 10 shows the positional relationship between the wave source position P and each receiver. FIG. 10 shows a wave source position P and positions AE of each receiver. In FIG. 10, 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 βb to βe are introduced. Parameter βb represents the difference between the distance r _a distance from r _b and the wave source position P from the wave source position P to the receiver 20-B to a receiver 20-A. Therefore, it is expressed as follows. In this specification, the parameters βb to βe may be referred to as “distance parameters”.
(Equation 6)
βb = r _b -r _a

Similarly, .beta.c, .beta.d and βe also represents the difference between the distance r _a from the wave source position P from the distance r _i and the wave source position P to the receiver 20-A to each receiver, collectively as follows It is written in.
(Equation 7)
βc = r _c -r _a
βd = r _d −r _a
βe = r _e −r _a

When Expressions 2 to 5 are transformed using Expressions 6 and 7, the following Expression 8 is obtained.

When the equations of Equations 1 and 8 are expanded and transformed, the following equations are obtained.

Now, the unknown number included in Equation 9 is replaced as follows.

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

Then, Equation 9 can be expressed as follows using a matrix.

Equation 11 can be expressed as follows using the matrix Q and the column vectors p and s.
(Equation 12)
Q ・ p = s

The vector s is obtained by subtracting the squares of the parameters βb to βe from the square of the distance from the reference point origin O to each receiver. Now, according to the definition of the parameters described above represents the difference parameters .beta.a, a distance r _a from the wave source position P to the receiver 20-A, the distance r _a from the wave source position P to the receiver 20-A Define the parameter βa. Then, βa = 0. That is, it can be said that the first row of the vector s is obtained by subtracting the parameter βa ² from the square of the distance from the origin O which is the reference position to the receiver A. It can be said that the vector s is obtained by subtracting the squares of the parameters βa to βe from the square of the distance from the origin O, which is the reference position, to each receiver.

If the parameter βa defined as described above is used, the (1, 5) component of the matrix Q can be considered to be “2 · βa”.

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 13)
p = Q ^-1 · s

Equation 13 is specifically expressed as follows.

As a condition for

satisfying Expressions

13 and 14, it is necessary that an inverse matrix of the matrix Q exists, in other words, the matrix Q is a regular square matrix. For this purpose, the determinant is not 0. 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 14, 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, at least two positions of the five receivers need to be at least the same because 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 βb to βe when obtaining the inverse matrix of the matrix Q will be described. As defined number 6 and 7, each parameter is the difference between the distance r _a from the wave source position P distance and from the wave source position P to the receiver 20-A to each receiver. The difference in the distance is proportional to the difference in arrival time of the signal wave output from the wave source position P. Therefore, a method for obtaining the difference in arrival time will be described below.

FIG. 11 shows the time t _k (k: a, b, c, d, when the signal wave output from the wave source position P reaches each receiver 20-K (K: A, B, C, D, E). It is a wave form diagram which shows e) typically. The signal wave radiated in all directions from the wave source reaches each receiver 20-K while being attenuated according to the propagation distance. Each receiver 20-K continuously receives a signal wave after each time t _k .

The inventor of the present application paid attention to the fact that the waveform of the signal wave received after each time t _k by each receiver 20-K has a strong correlation with each other. For example, the time waveform A of the signal wave received by the receiver 20-A after the time t _a and the time waveform B of the signal wave received by the receiver 20-B after the time t _b must consider the amplitude. For example, it can be said that they have substantially the same shape or the same phase.

If each receiver 20-K can output a waveform as shown in FIG. 11, it is easy to specify each time t _k . However, in practice, each receiver 20-K cannot practically output the time waveform of the signal wave in the manner shown in FIG. The reason is that each receiver 20-K continuously receives signal waves (incident signal waves) radiated from various wave sources in addition to the signal waves from the signal generator 10, and time waveform data of the incident signal waves. Is output. Further, various noises can be superimposed on the finally obtained time waveform data.

FIG. 12 schematically shows an example of a time waveform of a signal (output signal) output from each receiver 20-K. It is difficult to extract the time waveform of the signal wave received from the signal generator 10 from each time waveform shown.

Therefore, the inventors of the present application determine the time shift amount U at which the similarity between the two is strongest while shifting the other acquired time waveforms along the time axis with respect to the acquired one time waveform. Thought. Hereinafter, an example in which the time waveform B is shifted along the time axis with respect to the time waveform A will be described.

The inventor of the present application introduces the correlation function f (U) shown in Formula 15 in order to evaluate the similarity, and sets the time shift amount U that maximizes the value of the correlation function f _b (U) as shown in Formula 16. I came up with a decision.

In Equations 15 and 16, g _a is a time function representing the output signal from the receiver 20-A, and g _b is a time function representing the output signal from the receiver 20-B.

The determined shift amount U represents the time difference (t _b −t _a ) between the time t _a when the receiver 20-A receives the signal wave and the time t _b when the receiver 20-A receives the signal wave.

Assuming that the propagation speed of the signal wave output from the signal generator 10 is v, parameters βb to βe can be obtained by the calculation shown in Equation 17.
(Equation 17)
βb = v · argmax f _b (U)
βc = v · argmax f _c (U)
βd = v · argmax f _d (U)
βe = v · argmax f _e (U)

In Equation 15, f _c (U) to f _e (U) are g _b , a time function g _c representing the output signal from the receiver 20-C, and a time representing the output signal from the receiver 20-D. The function g _d is a correlation function obtained by replacing the function g _d with the time function g _e representing the output signal from the receiver 20-E.

The propagation velocity v is about 300,000 kilometers / second when the signal wave propagates through the atmosphere of 1 atm with electromagnetic waves. Alternatively, the propagation velocity v is about 331.5 meters / second when the signal wave is a sound wave and propagates through one atmosphere of dry air.

X _k , y _k , z _k (k: a, b, c, d, e) included in the right side of Equation 14 are the receivers 20-K (K: A, B, C, D, E). Each coordinate value of the position is known. Therefore, the inverse matrix Q ⁻¹ and the vector s on the right side of Equation 14 can all be obtained by calculation. Thereby, the components x, y, and z on the left side of Equation 14, that is, the position (x, y, z) of the wave source can be estimated.

In this specification, it is assumed that the time (processing time) required for each receiver to receive a signal from the signal generator 10 and output the signal is substantially equal. Even if they are not equal, information on the difference obtained by subtracting the processing time of the receiver A from the processing time of the other receivers may be acquired in advance and added to the obtained value U. Thereby, the time difference at which the signal from the signal generator 10 arrives can be obtained correctly.

The CPU 31 (FIG. 9) of the positioning device 30 executes a calculation according to the above-described principle. Hereinafter, the operation of the CPU 31 will be described with reference to FIGS. 13 and 14.

FIG. 13 shows the configuration of the processing block of the CPU 31. FIG. 14 is a flowchart showing the processing procedure of the CPU 31.

The CPU 31 functions as a parameter calculator 51, an inverse matrix calculator 52, and a vector multiplier 53. In FIG. 13, it is shown as if there are three components, but it actually means a unit of processing. In the present embodiment, the CPU 31 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 output signal data from each of the receivers 20-A to 20-E, and calculates the parameters βb to βe by performing the calculation shown in Equation 17 (step S1). Each calculated parameter is sent to the inverse matrix calculator 52.

The inverse matrix calculator 52 receives the parameters βb to βe from the parameter calculator 51. Further, the inverse matrix calculator 52 reads data indicating the position coordinates of each receiver stored in the memory 32 (step S2). Then, the inverse matrix calculator 52 calculates an inverse matrix of the matrix Q using the parameters βb to βe and data indicating the position coordinates of each receiver (step S3). 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 parameters βb to βe from the parameter calculator 51. 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 S4). As a result, the vector p on the left side of Equation 14 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 S5).

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

By the operation shown in Equation 10 above, the nonlinear terms were linearized and the unknowns increased. In addition, the introduction of unknowns r _a to the elements of the vector p. As a result, the number of 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 βb, βc, βd, and βe measured in advance and a set of x, y, and z estimated from them are associated with each other. When the time waveform data of the output signal is actually obtained and the set of βb, βc, βd, and βe is determined, the matching set is searched with reference to the 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 set that matches the actually measured set of βb, βc, βd, βe exists on the table.

Note that it is extremely easy to increase the number of entries in the table. In the environment where the positioning system 1 is introduced, each time a signal wave is received by each receiver while changing the position of the signal generator 10 serving as a wave source, a set of βb, βc, βd, βe is obtained, This is because a set of positions x, y, and z may 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.

In the above description, the time waveform data of the output signals from the five receivers is used to estimate the position of the signal generator 10, but the output signals from the six or more receivers are used. Time waveform data may be used.

In the above-described embodiment, the matrix Q when the vectors p and s are column vectors has been described. However, the matrix Q may be constructed using the vectors p and s as row vectors. It is clear that the transposition relation is mathematically the same.

According to the above processing, a system in which the signal generator informs the receiver of the signal generation time becomes unnecessary, and the disadvantage of the TOF method is solved.

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.

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, 51 parameter calculator, 52 inverse matrix calculator, 53 vector multiplier

Claims

A plurality of receivers each including five or more receivers, each receiving an incident signal wave including a signal wave output from a wave source and outputting time waveform data of the received incident signal wave Machine,
Receiving the time waveform data from each of the plurality of receivers;
Matrix Q vector p = vector s
(However, vector p: a vector including each coordinate component of the position of the wave source from the reference position as each component, vector s: the square of the distance from the reference position to each receiver, and the distance parameter of each receiver Vector with the difference from the square)
An inverse matrix Q −1 of at least a five-dimensional regular square matrix Q that satisfies the relational expression is calculated, the calculated inverse matrix Q −1 is applied to the vector s, and the wave source included in the vector p is calculated. An arithmetic circuit for calculating each coordinate component of the position is provided,
The distance parameter of each receiver is defined as a difference between a distance from the position of the wave source to a reference receiver among the plurality of receivers and a distance from the position of the wave source to each of the plurality of receivers. And
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 squares of the difference between each coordinate component of the position of each receiver and each coordinate component of the position of the wave source is a reference distance that is a distance between the wave source and the reference receiver, and a distance parameter of each receiver Transformed into the second relational expression equal to the square of the sum of
The sum of a quadratic term including each coordinate component of the position of the wave source, a first term, a square term of the reference distance, and a product term of the reference distance and the distance parameter of each receiver, Transformed into a third relational expression that is equal to the difference between the square of the distance from the reference position to each receiver and the square of the distance parameter of each receiver;
When the vector p is defined to further include a component obtained by replacing the difference between the quadratic term and the square term of the reference distance with a linear component, and a component of the reference distance term,
The arithmetic circuit is provided for each receiver.
While shifting the time waveform data output from each receiver along the time axis, the correlation with the time waveform data output from the reference receiver is calculated,
Determining the amount of time shift that maximizes the correlation;
A product of the determined time shift amount and the propagation speed of the signal wave output from the wave source is calculated as a distance parameter of each receiver,
A positioning system for obtaining an inverse matrix Q -1 of the matrix Q including a distance parameter term of each receiver as a row or column component to be multiplied with a component of the reference distance term.
In case the matrix Q is a five-dimensional regular square matrix, the reference position (0, 0, 0), the position of the wave source (x, y, z), the reference distance r a, the respective receiving If the position of the machine is (x i , y i , z i ) and the distance parameter of each receiver is β i (where i = a, b, c, d, e),
2. The positioning system according to claim 1, wherein the matrix Q, the vector p, and the vector s are expressed as Equation 1 below.
The ω included in the vector p represents a difference between the square of the distance from the reference position to the wave source and the square of the reference distance,
The β b , β c , β d, and β e included in the matrix Q and the vector s are the products of the time shift amount and the propagation speed of the signal wave output from the wave source determined for each receiver. The positioning system according to claim 2, wherein
The positioning system according to any one of claims 1 to 3, wherein the wave source emits an electromagnetic wave or a sound wave as the signal wave.
The positioning system according to any one of claims 1 to 4, further comprising an interface for outputting the coordinates of the wave source calculated by the arithmetic circuit.
A positioning device used in a positioning system,
The positioning system is a plurality of five or more receivers, each receiving an incident signal wave including a signal wave output from a wave source, and outputting time waveform data of the received incident signal wave A plurality of receivers,
The positioning device is
An input terminal for receiving the time waveform data from each of the plurality of receivers;
Matrix Q vector p = vector s
(However, vector p: a vector including each coordinate component of the position of the wave source from the reference position as each component, vector s: the square of the distance from the reference position to each receiver, and the distance parameter of each receiver Vector with the difference from the square)
An inverse matrix Q −1 of at least a five-dimensional regular square matrix Q that satisfies the relational expression is calculated, the calculated inverse matrix Q −1 is applied to the vector s, and the wave source included in the vector p is calculated. An arithmetic circuit for calculating each coordinate component of the position;
An output terminal that outputs data of each coordinate component of the position of the wave source calculated by the arithmetic circuit;
The distance parameter of each receiver is defined as a difference between a distance from the position of the wave source to a reference receiver among the plurality of receivers and a distance from the position of the wave source to each of the plurality of receivers. And
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 squares of the difference between each coordinate component of the position of each receiver and each coordinate component of the position of the wave source is a reference distance that is a distance between the wave source and the reference receiver, and a distance parameter of each receiver Transformed into the second relational expression equal to the square of the sum of
The sum of a quadratic term including each coordinate component of the position of the wave source, a first term, a square term of the reference distance, and a product term of the reference distance and the distance parameter of each receiver, Transformed into a third relational expression that is equal to the difference between the square of the distance from the reference position to each receiver and the square of the distance parameter of each receiver;
When the vector p is defined to further include a component obtained by replacing the difference between the quadratic term and the square term of the reference distance with a linear component, and a component of the reference distance term,
The arithmetic circuit is provided for each receiver.
While shifting the time waveform data output from each receiver along the time axis, the correlation with the time waveform data output from the reference receiver is calculated,
Determining the amount of time shift that maximizes the correlation;
A product of the determined time shift amount and the propagation speed of the signal wave output from the wave source is calculated as a distance parameter of each receiver,
A positioning apparatus that obtains an inverse matrix Q −1 of the matrix Q including a distance parameter term of each receiver as a row or column component to be multiplied by a component of the reference distance term.
A computer program executed by a computer provided in a positioning device of a positioning system,
The positioning system is a plurality of five or more receivers, each receiving an incident signal wave including a signal wave output from a wave source, and outputting time waveform data of the received incident signal wave A plurality of receivers,
The computer program is for the computer.
Reading data indicating data of the time waveform acquired from each of the plurality of receivers;
Matrix Q vector p = vector s
(However, vector p: a vector including each coordinate component of the position of the wave source from the reference position as each component, vector s: the square of the distance from the reference position to each receiver, and the distance parameter of each receiver Vector with the difference from the square)
Calculating an inverse matrix Q −1 of at least a five-dimensional regular square matrix Q that satisfies the relational expression:
Applying the calculated inverse matrix Q −1 to the vector s to calculate each coordinate component of the position of the wave source included in the vector p;
Outputting the data of each coordinate component of the position of the wave source calculated by the arithmetic circuit; and
The distance parameter of each receiver is defined as a difference between a distance from the position of the wave source to a reference receiver among the plurality of receivers and a distance from the position of the wave source to each of the plurality of receivers. And
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 squares of the difference between each coordinate component of the position of each receiver and each coordinate component of the position of the wave source is a reference distance that is a distance between the wave source and the reference receiver, and a distance parameter of each receiver Transformed into the second relational expression equal to the square of the sum of
The sum of a quadratic term including each coordinate component of the position of the wave source, a first term, a square term of the reference distance, and a product term of the reference distance and the distance parameter of each receiver, Transformed into a third relational expression that is equal to the difference between the square of the distance from the reference position to each receiver and the square of the distance parameter of each receiver;
When the vector p is defined to further include a component obtained by replacing the difference between the quadratic term and the square term of the reference distance with a linear component, and a component of the reference distance term,
The step of calculating the inverse matrix Q −1 includes:
For each receiver,
While shifting the time waveform data output from each receiver along the time axis, the correlation with the time waveform data output from the reference receiver is calculated,
Determining the amount of time shift that maximizes the correlation;
A product of the determined time shift amount and the propagation speed of the signal wave output from the wave source is calculated as a distance parameter of each receiver,
A computer program for obtaining an inverse matrix Q −1 of the matrix Q including a distance parameter term of each receiver as a row or column component to be multiplied with a component of the reference distance term.