JPWO2019031264A1 - Mobile positioning system and logistics management system - Google Patents

Abstract

A mobile body positioning system (100) of the present disclosure is arranged at a predetermined position with a mobile body (10) having an array antenna (12) and a processing circuit (14), and each periodically transmits a signal wave including identification information. Alternatively, it is provided with a plurality of beacons (20) that emit intermittently and a storage device (40) that stores data that associates each piece of identification information with each position of the plurality of beacons (20). The array antenna (12) has a plurality of antenna elements and sequentially or simultaneously receives the signal waves emitted from each of the plurality of beacons (20) and outputs an array signal. The processing circuit reads identification information from the received signal wave, refers to the data, and determines the position of at least one beacon that emitted the signal wave based on the identification information. The processing circuit estimates the arrival direction of the signal wave based on the array signal, and performs positioning of the moving body based on the position of at least one beacon that radiated the signal wave and the estimated arrival direction of the signal wave.

Description

The present application relates to a mobile positioning system and a physical distribution management system.

Development of an indoor positioning system that estimates the position of a mobile terminal or the like in an environment such as indoors where satellite waves cannot be received is being actively pursued. For example, when the beacon included in the mobile terminal emits a signal wave, the position of the mobile terminal can be estimated by receiving the signal wave with a plurality of array antennas fixed in the environment.

With one array antenna, the direction of a beacon that radiates an electromagnetic wave, that is, the arrival direction of a signal wave can be estimated. However, it is not possible to find the exact distance from the array antenna to the beacon. Therefore, in order to accurately estimate the position of the beacon, it is necessary to use multiple array antennas arranged at different positions and perform geometric calculation from the arrival direction of the signal wave with respect to each array antenna. There is.

Japanese Unexamined Patent Application Publication No. 2007-19828 discloses a technique of estimating the direction of an electromagnetic wave radiation source with one array antenna and displaying the estimated position in an image acquired by a camera. According to such a technique, it becomes possible to estimate the direction or position of the radio wave radiation source with reference to the layout of buildings and the like included in the image acquired by the camera.

JP, 2007-19828, A

According to the above-mentioned conventional technique, it is possible to estimate the direction of the radio wave radiation source by the array antenna, but the assumption is that the position itself of the array antenna is known.

Embodiments of the present disclosure provide a new mobile positioning system and logistics management system.

The mobile body positioning system of the present disclosure, in an exemplary embodiment, a mobile body having an array antenna and a processing circuit, and a signal wave arranged at a predetermined position, each of which includes identification information, is radiated periodically or intermittently. And a storage device that stores data that associates each piece of identification information with each position of the plurality of beacons. The array antenna has a plurality of antenna elements, receives the signal waves radiated from each of the plurality of beacons sequentially or simultaneously, and outputs an array signal from the plurality of antenna elements. The processing circuit reads the identification information from the received signal wave, refers to the data stored in the storage device, and based on the identification information, outputs at least one beacon that emitted the signal wave. The position is determined, the arrival direction of the received signal wave is estimated based on the array signal, and the position of the at least one beacon that emitted the signal wave and the estimated arrival direction of the signal wave are determined. Based on this, positioning of the moving body is performed.

Another mobile positioning system of the present disclosure is, in an exemplary embodiment, a mobile having an array antenna, a processing circuit, and a communication module, and a signal wave arranged at a predetermined position and each including identification information. A plurality of beacons that radiate intermittently or intermittently, and a storage device that stores data that associates the identification information with the respective positions of the plurality of beacons, and communicates with the mobile body via the communication module. And a management device. The array antenna has a plurality of antenna elements, receives the signal waves radiated from each of the plurality of beacons sequentially or simultaneously, and outputs an array signal from the plurality of antenna elements. The processing circuit estimates the arrival direction of the received signal wave based on the array signal, and reads the identification information from the received signal wave. The management device obtains the estimated direction of arrival of the signal wave and the identification information from the moving body via the communication module, refers to the data stored in the storage device, and identifies the identification information. The position of at least one beacon that radiated the signal wave is determined based on information, and the movement is based on the position of the at least one beacon that radiated the signal wave and the direction of arrival of the signal wave. Position your body.

In an exemplary embodiment, a physical distribution management system according to the present disclosure includes the mobile body positioning system described above, a sensing device that detects that a package carried by the mobile body has been unloaded from the mobile body, and the mobile body. A luggage position management device that stores the position of the luggage unloaded from the moving body based on the position of the moving body measured by a positioning system and the output of the sensing device.

According to the embodiments of the present disclosure, it is possible to measure the position of a moving body including an array antenna.

FIG. 1 is a diagram illustrating an exemplary configuration example of a mobile body positioning system according to an embodiment of the present disclosure. FIG. 2 is a diagram showing an example in which a plurality of beacons are arranged on the ceiling of a building such as a factory or a warehouse. FIG. 3 is a diagram showing a relationship between an array antenna having M antenna elements linearly arranged and a plurality of signal waves arriving from different directions. FIG. 4 is a diagram schematically showing an array antenna receiving the kth signal wave. FIG. 5 is a perspective view schematically showing the inside of a building such as a warehouse in which many beacons are arranged on the ceiling. FIG. 6 is a diagram schematically showing a configuration example of each beacon 20 in the embodiment of the present disclosure. FIG. 7A is a waveform diagram schematically showing a signal wave radiated from the beacon operating in the first mode at the first time interval T1. FIG. 7B is a waveform diagram schematically showing a signal wave radiated from the beacon operating in the second mode at the second time interval T2. FIG. 8 is a perspective view schematically showing a region C in which the estimation of the arrival direction by the array antenna shows relatively high accuracy. FIG. 9 is a plan view schematically showing a region C in which the estimation of the arrival direction by the array antenna shows relatively high accuracy. FIG. 10 is a diagram schematically showing the circumference P1 in which the moving body can exist when the angle α is 40° when the posture (direction) of the moving body is unspecified. FIG. 11 is a diagram schematically showing a circumference P2 in which the moving body can exist when the angle α is 20° when the posture of the moving body is unspecified. FIG. 12 is a diagram showing an example in which beacons are arranged at a relatively low density. FIG. 13A is a diagram schematically showing how the beacon operation is switched from the first mode to the second mode as the mobile body moves. FIG. 13B is a diagram schematically showing how the beacon operation is switched from the first mode to the second mode as the mobile body moves. FIG. 14 is a schematic layout diagram in the warehouse for explaining the embodiment of the physical distribution management system according to the present disclosure. FIG. 15 is a schematic layout diagram in a warehouse for explaining another embodiment of the physical distribution management system according to the present disclosure. FIG. 16 is a schematic layout diagram in a warehouse for explaining still another embodiment of the physical distribution management system according to the present disclosure.

Hereinafter, embodiments of the present disclosure will be described. In addition, more detailed description than necessary may be omitted. For example, detailed description of well-known matters and duplicate description of substantially the same configuration may be omitted. This is for avoiding unnecessary redundancy in the following description and for facilitating understanding by those skilled in the art. The inventors provide the accompanying drawings and the following description for those skilled in the art to fully understand the present disclosure. They are not intended to limit the claimed subject matter.

<Basic configuration example>
The present disclosure relates to a mobile positioning system and a physical distribution management system that uses the mobile positioning system.

First, an exemplary configuration example of a mobile body positioning system according to an embodiment of the present disclosure will be described with reference to FIG. 1.

The mobile body positioning system 100 in this example includes at least one mobile body 10 including an array antenna 12 and a processing circuit 14, and a signal wave that is arranged at a predetermined position and that includes identification information periodically or intermittently. And a plurality of beacons 20 that radiate. In FIG. 1, two moving bodies 10 are shown as an example. Typical examples of the mobile unit 10 are an automated guided vehicle, a guided vehicle, a mobile robot, and/or a drone.

In various embodiments, the plurality of beacons 20 may be arranged at grid point positions of a grid extending along a plane parallel to the floor surface. In certain embodiments, the plurality of beacons 20 may be arranged on the ceiling of a building. In the example of FIG. 1, N×M beacons 20 (N and M are positive integers) are periodically arranged in N rows and M columns in a two-dimensional plane. In FIG. 1, in order to distinguish each beacon 20, the beacon 20 (i, j) at the position of row i, column j (i and j are integers satisfying 1≦i≦N and 1≦j≦M) is (i, j). The reference numeral is attached. The array of beacons 20 is not limited to a rectangular array in rows and columns. Each beacon 20 may be arranged at an arbitrary position within a region having various shapes.

The mobile positioning system 100 according to the present disclosure includes a storage device 40 that stores data that associates each piece of identification information with each position of the plurality of beacons 20. This association can be represented by, for example, a detailed table showing the relationship (i,j)=(xi,yi) for all the beacons 20. Here, (xi, yi) is the position coordinates of the beacon (i, j). More specifically, for example, the position of the beacon (3, 2) located at the 3rd row and the 2nd column can be known to be (15, 20) by referring to the above data. .. When the reference position on the floor is the origin (0,0), the beacon (3,2) may be located 15 m to the east and 20 m to the north. In some cases, it is not necessary to know the exact position coordinate value. That is, in some cases, it may be sufficient to know from the identification information read from the signal wave that the beacon 20 that emits the signal wave is in the position of 3 rows and 2 columns. In the present disclosure, even in such a case, each piece of identification information is associated with each position of the plurality of beacons 20.

The storage device 40 may be included in the moving body 10 or may be placed at a position distant from the moving body 10. The moving body 10 shown on the left side of FIG. 1 has a storage device 40 built therein.

In the illustrated example, the plurality of beacons 20 and the mobile unit 10 each include a communication module CM that communicates according to the short-range wireless communication standard. When the storage device 40 is placed at a position distant from the mobile body 10, the mobile body 10 uses the communication module CM included in the mobile body 10 to acquire a part of the data from the storage device 40 by wireless communication. be able to. Part of the acquired data is held in a memory (not shown) included in the mobile unit 10.

The processing circuit 14 and the communication module CM can be realized by a single or a plurality of semiconductor integrated circuits. The processing circuit 14 may be called a processor such as a CPU (Central Processing Unit) or a computer. The processing circuit 14 can be realized by a circuit including a computer such as a general-purpose microcontroller or a digital signal processor, and a memory including a computer program that causes the computer to execute various instructions. The processing circuit 14 may include a register, a cache memory and/or a buffer (not shown).

FIG. 2 shows an example in which a plurality of beacons 20 are arranged on the ceiling C of a building such as a factory or a warehouse. In this example, the moving body 10 travels on the floor F. In the example shown in FIG. 2, signal waves W1, W2, W3, W4 and W5 are radiated from a plurality of beacons 20.

The beacon 20 is also called a tag. In an embodiment of the present disclosure, the beacon 20 may emit a signal wave according to the Bluetooth® low energy standard (advertising). The beacon 20 may be a device that operates according to another short-range wireless communication standard. The frequency of the signal wave is, for example, a microwave band or a millimeter wave band. The beacon 20 radiates a signal wave in the 2.4 GHz band, for example, at a time interval of 10 milliseconds or more and 10 seconds or less. The frequency of the signal wave does not have to be constant as long as it can be received by the array antenna 12, and a plurality of frequencies can be hopped.

The emission of the signal wave by the beacon 20 may have anisotropy that depends on the antenna of the beacon 20. The signal wave emitted by the beacon 20 may include additional information in addition to the identification information regarding the beacon 20. An example of the additional information is position coordinates of the beacon 20. The beacon 20 may be electrically connected to various external sensors. In such a case, the beacon 20 can also radiate various measurement values acquired by these sensors in a signal wave.

In the example of FIG. 2, the signal waves W1 to W5 emitted from the beacon 20 may enter the array antenna 12 of the moving body 10 at different angles. In the example of FIG. 2, the beacon 20 radiating the signal wave W1 exists in the direction of the arrow D1 starting from the center of the array antenna 12. Similarly, a beacon 20 emitting a signal wave W2 and a beacon 20 emitting a signal wave W3 are present in the directions of arrows D2 and D3 starting from the center of the array antenna 12, respectively. .. When the mobile unit 10 moves, the relative position of the beacon 20 with respect to the array antenna 12 changes. Therefore, the directions (angles) of the arrows D1-D3 directed to the beacon 20 with the center of the array antenna 12 as the starting point change as the moving body 10 moves.

FIG. 2 illustrates a moving body 10A that does not include the array antenna 12. The moving body 10A may follow the moving body 10 including the array antenna 12 or may be pulled by the moving body 10 to travel. Conversely, the moving body 10A that does not include the array antenna 12 may pull or guide the moving body 10 that includes the array antenna 12. FIG. 2 shows a user 1 carrying a wireless terminal. The user 1 can also communicate with the mobile unit 10 and/or the mobile unit 10A by a wireless terminal and transmit a traveling instruction. The user 1 may directly acquire the information indicating the position (self position) of the moving body 10 measured by the moving body 10 from the moving body 10. The type of steering of the moving body 10 is arbitrary. When the moving body 10 is a forklift, an operator can ride on the moving body 10 and drive the moving body 10.

<Array signal processing>
With reference to FIGS. 3 and 4, a configuration example of the array antenna 12 and a principle of the arrival direction estimation of a signal wave by the processing circuit 14 will be described. The array antenna 12 has a plurality of antenna elements arranged in a two-dimensional (planar) shape. The processing circuit 14 may be a computer that executes an arrival direction estimation algorithm to estimate the arrival direction of a signal wave.

For simplification, of the two-dimensionally arranged antenna elements, attention is paid to a linear array of antenna elements, and a technique for estimating the arrival direction of a signal wave incident on the linear array of antenna elements will be described. explain.

FIG. 3 shows an array antenna 12 having M antenna elements 12-1,..., 12-m,..., 12-M arranged linearly, and a plurality of signal waves arriving from different directions. The relationship with Wk is shown. Here, M is an integer of 2 or more, typically 4 or more, and m is an integer of 1 or more and M or less. Further, K is an integer of 1 or more, and k is an integer of 1 or more and K or less. The signal wave Wk is, for example, an electromagnetic wave emitted from the beacons 20 arranged on the ceiling C as shown in FIG. When the beacon 20 radiates a signal wave in accordance with the Bluetooth (registered trademark) Low Energy standard, this electromagnetic wave is a microwave radiated at a predetermined time interval and is modulated in the form of an advertising packet including identification information. ing.

A plurality of signal waves W1,..., Wk,..., WK coming from various angles are simultaneously or sequentially incident on the array antenna 12. The incident angle of the signal wave (angle θk indicating the arrival direction) represents the angle of the arrival direction with reference to the broadside B of the array antenna 12 (direction perpendicular to the plane where the antenna element groups are arranged). Attention is paid to the kth signal wave Wk. The “kth signal wave” means a signal wave identified by an incident angle θ _k when K signal waves are incident on the array antenna 12 from a plurality of beacons 20 existing in different directions. ..

FIG. 4 schematically shows the array antenna 12 receiving the kth signal wave. In the illustrated example, signals (array signals) are transmitted from the array antenna 12 including M antenna elements 12-1,..., 12-m,..., 12-M in response to the signal wave Wk. Is output. This array signal can be expressed as Equation 1 as a "vector" having M elements.
(Equation 1)
S=[S ₁ , S ₂ ,..., S _M ] ^T

Here, S _m (m: an integer of 1 to M; the same applies hereinafter) is the value of the signal received by the m-th antenna element. The superscript T means transposition. S is a column vector. The column vector S is given by the product of the direction vector (steering vector or mode vector) determined by the configuration of the array antenna 12 and the complex vector indicating the signal wave in the beacon 20 which is the wave source (signal source). When the number of wave sources is K, the waves of signals arriving from the wave sources to the individual antenna elements are linearly superimposed. At this time, S _m can be expressed as in Equation 2.

In Equation 2, a _k , θ _k, and φ _k are the amplitude of the k-th signal wave, the incident angle of the signal wave (the angle indicating the arrival direction), and the initial phase, respectively. Further, λ is the wavelength of the incoming wave, and j is an imaginary unit.

As can be understood from Expression 2, S _m is expressed as a complex number composed of a real part (Re) and an imaginary part (Im). Further generalizing in consideration of noise (internal noise or thermal noise), the array signal X can be expressed as shown in Equation 3.
(Equation 3)
X=S+N

N is a vector representation of noise. The processing circuit 14 obtains the autocorrelation matrix Rxx (Equation 4) of the incoming wave using the array signal X shown in Equation 3.

Here, the superscript H represents a complex conjugate transpose (Hermitian conjugate). The processing circuit 14 calculates the eigenvalue of the autocorrelation matrix Rxx. Of the plurality of obtained eigenvalues, the number of eigenvalues (signal space eigenvalues) having a value equal to or larger than a predetermined value determined by thermal noise corresponds to the number of incoming waves. Then, by calculating the angle at which the likelihood of the arrival direction of the signal wave becomes maximum (maximum likelihood), the number and direction of the beacons 20 that emitted the received signal wave can be specified. The method of estimating the angle indicating the arrival direction of the signal wave is not limited to this example. This can be done using various DOA estimation algorithms.

When the linear array of antenna elements is used, the arrival direction of the wireless signal can be estimated with respect to the direction (first direction) in which the phase difference occurs in the wireless signals incident on the array of antenna elements. However, the arrival direction of the radio signal cannot be estimated for the second direction perpendicular to the first direction. In order to estimate the arrival direction with respect to the second direction, it is necessary to use two-dimensional (planar) antenna elements. Since the technique of calculating the angles in both the first direction and the second direction using the antenna elements arranged two-dimensionally is well known, detailed description thereof will be omitted.

In this embodiment, the array antenna 12 has a diameter of, for example, about 20 cm, and includes, for example, seven antenna elements arranged two-dimensionally in a plane. The weight of the array antenna 12 is, for example, about 500 grams. The configuration and size of the array antenna 12 are not limited to this example. The appearance shape of the array antenna 12 when viewed from the top surface does not have to be circular, and may be an elliptical shape, a rectangular shape, a polygonal shape, a star shape, or another shape. The number of antenna elements may be eight or more, or may be within the range of 3 to 6.

The antenna elements in the embodiments of the present disclosure are arranged in a plane parallel to the floor F. Specifically, six antenna elements may be arranged concentrically around one antenna element located at the center of the array antenna 12 at equal intervals. This arrangement is just an example.

The array antenna 12 may include a high frequency circuit such as a monolithic microwave integrated circuit (not shown) and an AD conversion circuit. Instead of being provided in the array antenna 12, such a circuit may be connected between the processing circuit 14 and the array antenna 12.

As described above, in the embodiment of the present disclosure, the array antenna 12 has a plurality of antenna elements, receives the signal waves radiated from each of the plurality of beacons 20 sequentially or simultaneously, and outputs the array signals from the plurality of antenna elements. Output. The processing circuit 14 reads the identification information from the received signal wave. Then, by referring to the data stored in the storage device 40, the position of at least one beacon that emitted the signal wave is determined based on the identification information. The processing circuit 14 estimates the arrival direction of the signal wave based on the array signal output from the array antenna 12, and estimates the angle that defines the arrival direction of the signal wave. The arrival direction of the signal wave may be referred to as DOA (Direction Of Arrival) or AOA (Angle Of Arrival).

The arrival direction of the signal wave estimated by the above method is defined by the angle (polar coordinates) with the moving body 10 as a reference. On the other hand, the position of each of the plurality of beacons 20 is known. Therefore, by reading the identification information from the signal wave, the beacon 20 that has emitted the signal wave can be specified. As described above, the storage device 40 stores data that associates each piece of identification information with each position of the plurality of beacons 20. By referring to this data, the position of the beacon 20 specified by the identification information can be grasped.

FIG. 5 is a perspective view schematically showing the inside of a building such as a warehouse in which a large number of beacons 20 are arranged on the ceiling C. FIG. 5 shows three moving bodies 10a, 10b, 10c that receive signal waves radiated from one or a plurality of beacons 20 and travel while executing positioning (localization or positioning). FIG. 5 shows a management device 30 that manages the operation of the moving bodies 10a, 10b, and 10c.

In addition, in FIG. 5, the individual beacons 20 are illustrated in a large size so that the beacons 20 are conspicuous. The beacon 20 may have a small size, for example, about 1 cm×1 cm. The beacon 20 may be embedded in the ceiling C so that it cannot be visually recognized by a person. Some of the plurality of beacons 20 may be attached to fixed objects such as walls, windows, and columns. The mounting surface such as the ceiling does not need to be flat, and all the beacons 20 do not need to be located in one plane.

As shown in FIG. 5, in a form in which a large number of beacons 20 are arranged in a wide range, if all beacons 20 continuously emit a signal wave, the power consumption of each beacon 20 excessively increases. Resulting in. Therefore, it is preferable that the beacon 20 has a function of changing the interval (time period) of signal wave emission (broadcast).

FIG. 6 is a diagram schematically showing a configuration example of each beacon 20 in the embodiment of the present disclosure. As shown in FIG. 6, the beacon 20 has an antenna 24 that radiates a signal wave, a semiconductor integrated circuit 26 connected to the antenna 24, and a battery (battery) 28 that operates as a power supply. The antenna 24 is a small antenna and does not have to be an array antenna. The semiconductor integrated circuit 26 may include a processor, a memory, a high frequency oscillator circuit, and the like.

In some embodiments, each of the plurality of beacons 20 operates in a first mode that emits a signal wave at a first time interval and a signal wave at a second time interval that is shorter than the first time interval. It is possible to operate in a second mode that emits Each of the plurality of beacons 20 may have a light source 22 that emits visible light when operating in the second mode.

The plurality of beacons 20 are detachably attached to predetermined positions whose coordinates are known. The beacon 20 whose supply voltage of the battery 28 has dropped due to long-term use may be removed from a predetermined position and replaced with a new beacon. Only the battery 28 of the beacon 20 may be replaced with a new battery.

Each of the plurality of beacons 20 may be attached to, for example, a plurality of lighting fixtures arranged on the ceiling. Each lighting device has a lighting circuit that receives power from a power line or the like. Beacon 20 may be powered from such a lighting circuit. Further, since the beacon 20 consumes little power, an element such as a small solar cell that converts light emitted from the light source of the lighting fixture into electric power may be used as the power source of the beacon 20 instead of the battery.

FIG. 7A is a waveform diagram schematically showing a signal wave emitted from beacon 20 operating in the first mode at first time interval T1. A plurality of rectangular portions indicated by arrows indicate periods during which signal waves are being emitted. The first time interval T1 can be set to, for example, 5 seconds or more.

FIG. 7B is a waveform diagram schematically showing a signal wave radiated from the beacon 20 operating in the second mode at the second time interval T2. A plurality of rectangular portions indicated by arrows indicate periods during which signal waves are being emitted. The second time interval T2 may be set to 1 second or less, for example 500 milliseconds or less.

The beacon 20 is normally operating in the first mode. However, for example, when the moving body 10 approaches, the operation can be switched from the first mode to the second mode. In order to detect that the moving body 10 is approaching, various configurations can be adopted. According to a certain example, a request signal wave (request) is transmitted to the beacon 20 from the mobile body 10 that has detected the specific beacon 20. Specifically, the mobile unit 10 can determine whether the number of at least one beacon that emitted the signal wave is single or plural by reading the identification information from the received signal wave. When the number of beacons 20 that have emitted a signal wave is singular, the request signal wave is transmitted to this single beacon 20. On the other hand, when the number of beacons 20 that emitted the signal wave is plural, the request signal wave is transmitted to some beacons 20 selected from the plurality of beacons 20. Typically, the request signal wave can be sent to the beacon 20 closest to the current position of the mobile unit 10. Each of the plurality of beacons 20 switches from the first mode to the second mode when receiving the request signal wave while operating in the first mode. By doing so, the inefficient consumption of electric power due to the radiation of the signal wave is suppressed. As a result, the life of the battery 28 is extended. When complying with the Bluetooth® low energy standard, the beacon 20 can act as an advertiser and the mobile 10 with the array antenna 12 can act as a scanner. The signal wave radiated by the beacon 20 can transmit the identification information and the like to the mobile unit 10 in the form of an advertising packet, as described above.

In the example of FIG. 2, the beacon 20 emitting the signal waves W3, W4, W5 operates in the first mode, and the beacon 20 emitting the signal waves W1, W2 operates in the second mode. doing. The beacon 20 operating in the first mode is located farther from the moving body 10 than the beacon 20 operating in the second mode.

<Positioning>
As described above, as a result of the operation of the array antenna 12 and the processing circuit 14, the arrival direction of the received signal wave can be estimated. However, the arrival direction of the signal wave is the direction of the beacon 20 that has emitted the signal wave with reference to the moving body 10. Hereinafter, an example of a method for obtaining the position and orientation of the moving body 10 based on the arrival direction of the signal wave emitted by the beacon 20 will be described.

Please refer to FIG. 8 and FIG. FIG. 8 is a perspective view schematically showing a region C in which the estimation of the arrival direction by the array antenna 12 shows relatively high accuracy. FIG. 9 is a plan view schematically showing the region C.

The range of the area C in which the estimation of the arrival direction by the array antenna 12 shows relatively high accuracy is defined by a cone having the area C as the bottom surface. The height H of this cone corresponds to the distance from the array antenna 12 to the array surface of the beacon 20. The center of the array antenna 12 is located at the apex of the cone, and the apex angle of the cone corresponds to the angle of view of the array antenna 12. The size of the cone depends on the sensitivity and directivity of the array antenna 12 and the signal wave radiation power and directivity of the beacon 20.

The mobile 10 is able to communicate with multiple beacons 20 located outside this cone. However, the estimation accuracy of the direction of arrival of the received signal wave tends to decrease as the distance from the cone increases. In order to perform positioning (position estimation) with high accuracy, it is preferable to use the beacon 20 located inside the area C.

In the examples shown in FIGS. 8 and 9, the arrival direction D of the signal wave emitted from the beacon 20X is specified by the angle α and the angle β. FIG. 8 shows the w axis of local coordinates (moving body coordinates) unique to the moving body 10, and FIG. 9 shows the u axis and v axis of this local coordinate. The uv plane is parallel to the floor. The w axis is parallel to the vertical direction (height direction). The u-axis, v-axis, and w-axis form right-handed uvw coordinates that are orthogonal to each other. On the other hand, the coordinates peculiar to a building such as a warehouse are right-handed XYZ coordinates constituted by X-axis, Y-axis, and Z-axis which are orthogonal to each other. The XYZ coordinates are global world coordinates that do not depend on the position and orientation (orientation) of each moving body 10.

As shown in FIG. 8, the angle α is the angle between the arrival direction D and the w axis. On the other hand, as shown in FIG. 9, the angle β is the angle (azimuth) between the line segment formed by projecting the arrival direction D perpendicularly to the u-v plane and the u-axis. Here, if the orientation of the moving body 10 is unknown, the angle between the X axis in world coordinates and the u axis in moving body coordinates is unknown.

As described above, the position coordinates of the beacon 20X are acquired based on the identification information included in the signal wave. Moreover, the arrival direction (estimated values of the angle α and the angle β) of the signal wave from the beacon 20X is obtained by the array signal processing. However, since the estimated values of the angle α and the angle β are values based on the moving body 10, the position coordinates of the moving body 10 on the global coordinates cannot be determined unless the orientation of the moving body 10 is determined.

FIG. 10 is a diagram schematically showing the circumference P1 in which the moving body 10 can exist when the angle α of the arrival direction is 40° when the direction of the moving body 10 is unspecified. On the other hand, FIG. 11 is a diagram schematically showing the circumference P2 in which the moving body 10 can exist when the angle α of the arrival direction is 20° when the direction of the moving body 10 is unspecified. .. As can be seen from FIGS. 10 and 11, the smaller the angle α, the narrower the range in which the moving body 10 may exist. When the orientation of the moving body 10 is known, the position of the moving body 10 can be specified at one point on the circumference P1 or P2.

When the moving body 10 receives one signal wave and only one beacon 20 exists ahead of its arrival direction, if the direction of the moving body 10 is unknown in this way, the position of the moving body 10 is Become unspecified. However, the position and orientation of the moving body 10 can be calculated based on the coordinates of the plurality of beacons 20 as long as the arrival directions of the signal waves from the plurality of (preferably three or more) beacons 20 can be estimated. That is, for example, the moving body 10 exists at the intersection of the circumference P1 on the bottom surface of the cone having the beacon 20X as the apex and the circumference on the bottom surface of the cone having the beacon 20X as the apex shown in FIG. Will be. This makes it possible to estimate not only the position of the moving body 10 but also the posture (angle). Therefore, the arrangement of the beacons 20 is preferably determined so that the region C (FIGS. 8 and 9) always includes a plurality of beacons 20. However, even if the number of beacons 20 included in the region C temporarily becomes 1 in the process of the moving body 10 moving, the direction of the moving body 10 until then is known, and If it can be assumed that the orientation is maintained during traveling, the position of the moving body 10 can be specified.

Next, referring to FIG. In FIG. 12, the beacons 20 are arranged at a relatively lower density than in FIG. 9. Since the origin of the uv plane of the moving body coordinates moves on the XY plane of the global coordinates, the origin of the uv plane does not necessarily match the origin of the XY plane. However, FIG. 12 schematically shows a state in which the two origins are coincident with each other, and represents an angle Θ indicating the rotation of the u axis with respect to the X axis.

As described above, even if the angles α and β indicating the arrival directions of a certain beacon 20 are obtained, if the direction of the moving body 10, that is, the angle θ is unknown, the position of the origin of the uv plane (movement) The position of the body is not determined around the beacon 20 (a region where the beacon 20 can be seen at the angle α).

In FIG. 12, a first region C1 corresponding to the region C shown in FIG. 9 and a second region C2 wider than the first region C1 are described. Compared to the beacon 20 located in the first area C1, the beacon 20 located in the second area C2 has relatively low accuracy of estimation of the arrival direction. However, by using the signal wave from the beacon 20 located in the second area C2 in addition to the signal wave from the beacon 20 located in the first area C1, it is possible to estimate the position and orientation of the moving body 10. Is. Outside the first region C1, the estimation accuracy of the angle β, which is the azimuth angle, is higher than that of the angle α. Therefore, the information of the angle β has relatively high accuracy even if the signal wave from the beacon 20 located further away is used, and it is possible to obtain useful information for obtaining the direction of the moving body 10. Is.

13A and 13B schematically show how the operation of the beacon 20 is switched from the first mode to the second mode as the moving body 10 moves. In these figures, the beacon 20 operating in the first mode is shown as a white rectangle, while the beacon 20a operating in the second mode is shown as a hatched rectangle. The beacon 20a operating in the second mode is selected along the planned route of the mobile unit 10. The mobile unit 10 can distinguish the beacon 20a operating in the second mode from the beacon 20 operating in the first mode by measuring the time interval for receiving the signal wave. By detecting the beacon 20a operating in the second mode, the moving body 10 can know the route (traveling direction) to travel.

The above operation can be realized by the system using the operation management device of the mobile unit 10. In one embodiment, the mobile positioning system includes an operation management device 30. The operation management device 30 performs wireless communication with the plurality of beacons 20 and switches the operation of one or a plurality of beacons 20 selected from the plurality of beacons 20 from the first mode to the second mode. The operation management device 30 sequentially switches the operation of the plurality of beacons 20 from the first mode to the second mode along the movement route of the moving body 10. Further, the moving body 10 moves so as to approach the beacon 20a operating in the second mode.

Note that the operation management device 30 can track the position of the mobile body 10 by acquiring the self-position information obtained by the mobile body 10 by the array signal processing from the mobile body 10 by wireless communication.

In the above-described embodiment, the moving body 10 performs the arithmetic processing for positioning. The mobile positioning system of the present disclosure is not limited to this example. In another embodiment, the management device 30 executes the arithmetic processing for determining the position of the moving body 10 instead of the moving body 10. The mobile body positioning system of such an embodiment also includes the mobile body 10 and the plurality of beacons 20 described above. The mobile positioning system is a management device that has a storage device that stores data that associates identification information with the positions of a plurality of beacons. The management device 30 communicates with the mobile device 10 via a communication module. Equipped with. The management device 30 acquires the estimated arrival direction of the signal wave and the identification information from the moving body via the communication module. Then, the data stored in the storage device is referenced. In addition, the position of at least one beacon that emitted the signal wave is determined based on the identification information. Furthermore, the management device 30 can estimate the position of the moving body 10 based on the position of at least one beacon 20 that has emitted the signal wave and the arrival direction of the signal wave.

The present disclosure also relates to a physical distribution management system including various mobile body positioning systems described above. This physical distribution management system includes a sensing device that detects that a load carried by a mobile object has been unloaded from the mobile object. The sensing device may be a mobile terminal carried by a worker who drives a mobile body. Further, the sensing device may be a weight sensor attached to the moving body. In the case of a mobile terminal, by operating the touch screen, the worker inputs the number and the like of the unloaded goods into the sensing device. The physical distribution management system includes a package position management device that stores the position of the package unloaded from the mobile unit based on the position of the mobile unit measured by the mobile body positioning system and the output of the sensing device.

FIG. 14 is a schematic layout diagram in the warehouse for explaining the embodiment of the physical distribution management system according to the present disclosure. In this example, N×M beacons 20 (N and M are positive integers) are periodically arranged in N rows and M columns on the ceiling of the warehouse. In FIG. 14, in order to distinguish each beacon 20, the beacon 20 (i, j) at the position of row i and column j (i and j are integers satisfying 1≦i≦N and 1≦j≦M) is (i, j). The reference numeral is attached.

The moving body 10 in this example is a manned carrier truck. The moving body 10 moves into the warehouse with the sensing device 55 mounted. Steering is performed by a user (worker or driver) who is in the moving body 10. The moving body 10 moves along the route indicated by the broken line. The route is not limited to the example shown and may have a more complicated pattern. In the middle of the route, the worker unloads the luggage 60 and the luggage 62 at different positions. At the time of unloading, the operator performs an operation on the sensing device 55 to indicate that the unloading has been performed. In this embodiment, the sensing device 55 transmits to the package position management device 50 by wireless communication that the package has been unloaded from the moving body 10 in response to an input operation by an operator. In this way, the luggage position management device 50 can store that the luggage has been placed in association with the position of the moving body 10 at that time. The position of the moving body 10 can be acquired based on the tracking of the moving body 10 by the moving body positioning system mentioned above. In addition, the positioning of the moving body 10 by the moving body positioning system may be executed when the sensing device 55 is input by an operator.

A person who steers the moving body 10 does not need to know the traveling route of the moving body 10 in advance, and may move the moving body 10 in the warehouse and unload the luggage in an appropriate empty space.

The luggage position management device 50 may also serve as the operation management device 30 of the moving body 10. In this case, the baggage position management device 50 determines the appropriate traveling route in order to let the worker know the position where the luggage should be placed, and then operates the beacon 20 along the traveling route from the first mode to the second mode. You may switch to. When the light source 22 of the beacon 20 operating in the second mode emits visible light, a person who steers the moving body 10 can run the moving body 10 along the running route by relying on the light emission state of the light source 22. become.

<Other Embodiments>
In some cases, accurate position coordinates may not be necessary for the traveling position of the moving body 10 or the unloading position. In such a case, it suffices to be able to specify which of the plurality of partitioned areas respectively assigned to the plurality of beacons 20 as the “position”.

FIG. 15 is a diagram showing another embodiment of the physical distribution management system according to the present disclosure. FIG. 15 shows a plurality of partitioned areas 70 respectively assigned to the plurality of beacons 20. The partitioned area 70 is partitioned by a boundary line 200 that is a chain line extending vertically and horizontally. The boundary line 200 is a virtual line and does not have to be actually drawn on the ceiling or floor of the building.

In the example of FIG. 15, the package 60 is placed in the partitioned area 70 assigned to the beacon 20 having the identification number of ID21. On the other hand, the package 62 is placed in the partitioned area 70 assigned to the beacon 20 having the identification number of ID38.

As described above, the positions of the packages 60 and 62 in the present embodiment are specified not by the specific values of the global coordinates but by the division area unit. As described above, according to the mobile body positioning system of the present disclosure, it is possible to detect the identification information unique to the beacon 20 at the closest position when the mobile body 10 is unloaded. With this identification information, it is possible to specify the position where the package is placed in units of divided areas. The beacon closest to the moving body 10 is a beacon that indicates the arrival direction with the smallest angle α shown in FIG. 8 with respect to the array antenna that has received the signal wave.

In this case, it is not necessary to know the direction of the moving body 10 (angle Θ in FIG. 12). Therefore, if the arrival direction of the signal wave (particularly the angle α) can be estimated, it is easy to identify the beacon 20 located closest to the moving body 10.

FIG. 16 is a diagram showing yet another embodiment of the physical distribution management system according to the present disclosure. In this example, the array of beacons 20 does not have a constant period. Since the partitioned area 70 can be determined according to the area where the luggage is placed, the beacon 20 can be arranged at a position corresponding to, for example, the center of the partitioned areas 70 having different sizes.

INDUSTRIAL APPLICABILITY The mobile body positioning system according to the present disclosure is suitably used for positioning a mobile body indoors. Further, even outdoors, by appropriately arranging the beacon, it is possible to use it for positioning the moving body. Further, it can be suitably used for transportation and position management of parts, finished products, luggage, etc. in a distribution warehouse, factory, hospital, airport and the like.

10... Moving object, 12... Array antenna, 14... Processing circuit, 20... Beacon, 22... Light source, 24... Antenna, 26... Semiconductor integrated circuit, 28... -Battery, 30... Management device, 40... Storage device, 50... Luggage position management device

Claims (18)

A mobile having an array antenna and a processing circuit;
A plurality of beacons arranged at predetermined positions, each of which radiates a signal wave containing identification information periodically or intermittently,
A storage device that stores data that associates each identification information with each position of the plurality of beacons,
Equipped with
The array antenna has a plurality of antenna elements, and outputs an array signal from the plurality of antenna elements by sequentially or simultaneously receiving the signal waves emitted from each of the plurality of beacons,
The processing circuit is
Reading the identification information from the received signal wave,
Referring to the data stored in the storage device, based on the identification information, determine the position of at least one beacon that emitted the signal wave,
Based on the array signal, estimating the arrival direction of the received signal wave,
A mobile body positioning system that performs positioning of the mobile body based on the position of the at least one beacon that radiated the signal wave and the estimated arrival direction of the signal wave. The mobile positioning system according to claim 1, wherein the plurality of beacons are arranged at grid point positions of a grid extending along a plane parallel to the floor surface. The mobile positioning system according to claim 1, wherein the plurality of beacons are arranged on a ceiling of a building. The mobile body positioning system according to claim 1, wherein the plurality of beacons and the mobile body each include a communication module that communicates according to a short-range wireless communication standard. 5. The processing circuit according to claim 1, wherein the processing circuit obtains the attitude of the moving body based on the position of the at least one beacon that has emitted the signal wave and the estimated arrival direction of the signal wave. The mobile positioning system according to. Each of the plurality of beacons is
Operating in a first mode of emitting the signal wave at a first time interval and operating in a second mode of emitting the signal wave at a second time interval shorter than the first time interval. The mobile positioning system according to any one of claims 1 to 5, which is possible. The mobile positioning system according to claim 6, wherein each of the plurality of beacons has a light source that emits visible light when operating in the second mode. The mobile body, after reading the identification information from the received signal wave, transmits a request signal wave to the singular beacon when the number of the at least one beacon that radiated the signal wave is singular, When the number of the at least one beacon radiating the signal wave is a plurality, the request signal wave is transmitted to some beacons selected from the plurality of beacons,
8. The beacon according to claim 6, wherein each of the plurality of beacons switches from the first mode to the second mode when receiving the request signal wave while operating in the first mode. Mobile positioning system. The operation management device for the mobile body is provided,
The operation management device performs wireless communication with the plurality of beacons to switch the operation of one or more beacons selected from the plurality of beacons from the first mode to the second mode, The mobile positioning system according to any one of claims 6 to 8. The operation management device causes the operations of the plurality of beacons to be sequentially switched from the first mode to the second mode along a movement route of the mobile body,
The mobile body positioning system according to claim 9, wherein the mobile body moves so as to approach a beacon operating in the second mode. Each of the plurality of beacons has an antenna that radiates the signal wave, a semiconductor integrated circuit connected to the antenna, and a battery that operates as a power source, and is detachably attached to the predetermined position. The mobile positioning system according to claim 1, wherein The mobile body positioning system according to any one of claims 1 to 11, wherein the mobile body includes any one of an unmanned transport vehicle, a manned transport vehicle, a mobile robot, and a drone. The operation management device for the mobile body is provided,
The mobile body according to any one of claims 1 to 12, wherein the operation management device acquires information indicating the measured position of the mobile body from the mobile body by wireless communication and tracks the position of the mobile body. Positioning system. The mobile body positioning system according to claim 1, wherein the mobile body includes the storage device. The storage device is remote from the moving body,
The mobile body positioning system according to claim 1, wherein the mobile body acquires a part of the data from the storage device by wireless communication. A mobile having an array antenna, a processing circuit, and a communication module;
A plurality of beacons arranged at predetermined positions, each of which radiates a signal wave containing identification information periodically or intermittently,
A management device that has a storage device that stores data that associates the identification information with each position of the plurality of beacons, and that communicates with the mobile object via the communication module,
Equipped with
The array antenna has a plurality of antenna elements, and outputs the array signal from the plurality of antenna elements by sequentially or simultaneously receiving the signal waves emitted from each of the plurality of beacons,
The processing circuit, based on the array signal, estimates the arrival direction of the received signal wave, reads the identification information from the received signal wave,
The management device is
Via the communication module, the estimated direction of arrival of the signal wave and the identification information are obtained from the mobile body,
Referring to the data stored in the storage device, based on the identification information, determine the position of at least one beacon that emitted the signal wave,
A mobile body positioning system that performs positioning of the mobile body based on a position of the at least one beacon that radiates the signal wave and the arrival direction of the signal wave. A mobile body positioning system according to any one of claims 1 to 16,
A sensing device that detects that a load carried by the moving body has been unloaded from the moving body,
A position of the moving body measured by the moving body positioning system, and an output of the sensing device, based on the output of the sensing device, a luggage position management device that stores the position of the luggage unloaded from the moving body,
A logistics management system equipped with. The physical distribution according to claim 17, wherein the sensing device detects that the package has been unloaded from the moving body in response to an input operation by a user, and transmits the output to the package position management device by wireless communication. Management system.

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