JP7660465B2 - Location estimation system and cluster location estimation method - Google Patents

Description

The present invention relates to a technology for estimating the current position of containers, carts, pallets, etc. (hereinafter simply referred to as "cargo platforms") used to transport cargo, and in particular to a technology that enables efficient management of the current positions of multiple cargo platforms accumulated at bases such as warehouses and collection points.

There has been a demand for technology that can efficiently manage the current location of a loading platform. Patent Document 1 discloses a technology that estimates the current location by wirelessly receiving signals transmitted from multiple Wi-Fi access points (also called "APs"), acquiring the MAC address, which is an identifier contained in each signal, and extracting the location information of the Wi-Fi access point associated with each MAC address from a database.

Patent document 2 discloses a technology that reads IDs from communication terminals installed in vehicles and containers and manages vehicles and containers on a group basis.

Special Publication No. 2012-525569 JP 2021-60743 A

When managing the locations of loading bays using the invention disclosed in Patent Document 1, location information for each loading bay is extracted from a database, so the more loading bays there are, the more frequently the database is accessed. Since the amount charged for such a database increases according to the number of accesses, it is desirable to reduce the number of accesses.

It is therefore conceivable to manage the locations of the loading bays on a group basis, but the method disclosed in Patent Document 2 requires the deployment of a management worker at the site where the loading bays are piled up. Specifically, the management worker must use a device such as a reader to read the IDs of multiple loading bays, and then issue an instruction to determine that these loading bays belong to a group, thereby determining the group of loading bays.

The present invention aims to provide a system that can automatically cluster accumulated cargo bins and grasp and manage the positions of the cargo bins on a cluster basis without the need for on-site management personnel to check groups of cargo bins.

(1) In order to solve the above problem, a location estimation system according to one aspect of the present disclosure includes a plurality of communication terminals that sequentially transmit messages to a management server, the messages including the identifiers of one or more acquired access points and a terminal ID that identifies each communication terminal, a management server, and a location information server that associates and stores location information indicating the locations of the access points with the identifiers. The management server includes a server receiving unit, a server storage unit, a clustering unit, a location request unit, and a location estimation unit. The server receiving unit receives messages sequentially transmitted from the plurality of communication terminals. The server storage unit sequentially updates and stores the messages for each terminal ID. The clustering unit clusters the plurality of messages into clusters based on the identifiers included in the stored messages. The location request unit transmits the identifiers included in the clusters to the location information server and requests the location information associated with the identifiers. The location estimation unit receives the location information transmitted from the location information server and estimates the location indicated by the location information as the estimated location of the communication terminal that is the sender of the messages included in the cluster.

(2) The position estimation system of (1) may further include a map storage unit and a display unit. The map storage unit stores map information representing a map. The display unit displays a map based on the map information and displays an icon indicating a cluster superimposed on the estimated position on the displayed map.

(3) The position estimation system of (2) may further include a counting unit. The counting unit counts the number of messages included in a cluster as the number of communication terminals. The display unit may display the number counted by the counting unit on a map by superimposing it thereon.

(4) The position estimation system of (2) or (3) may further include a user terminal. The user terminal includes a map storage unit, a display unit, and a user terminal communication unit. The user terminal communication unit may receive estimation information including the estimated position from the management server.

(5) The communication terminal of any one of the position estimation systems (1) to (4) may include an acquisition unit, a storage unit, a priority identifier storage unit, and a transmission unit. The acquisition unit receives signals from the multiple access points that wirelessly transmit signals including identifiers and sequentially acquires identifiers. The storage unit stores the identifiers. The priority identifier storage unit stores a priority identifier indicating an identifier that should be preferentially selected. The transmission unit preferentially selects, from among the identifiers, an identifier that matches the priority identifier, and sequentially transmits messages including a predetermined number of identifiers and a terminal ID to the management server.

(6) The communication terminal of any one of the position estimation systems (1) to (5) may be installed on a loading platform or a moving body, and the position estimation unit may estimate the position of the loading platform or the moving body.

(7) In order to solve the above problems, a cluster location estimation method that is one aspect of the present disclosure receives messages from multiple communication terminals, each message including an identifier of one or more access points and a terminal ID that identifies each communication terminal, sequentially updates and stores the messages for each terminal ID, clusters the messages into clusters based on the identifiers included in the stored messages, extracts associated location information using the identifiers included in the clusters from a database that stores location information indicating the locations of access points in association with the identifiers of the access points, and estimates the location indicated by the extracted location information as the location of the communication terminal that is the sender of the messages included in the cluster.

By using a location estimation system incorporating the present invention, maintenance workers no longer need to check the grouping of cargo bays on-site, and the number of times they need to access the location information database can be reduced.

FIG. 1 is a diagram illustrating an example of the configuration of a position estimation system 100. 1 is a diagram showing an example of a group of beds 10a in which beds 1a, 1b, and 1c are stacked together. 2 is a diagram showing an example of a functional configuration of a communication terminal 11 installed on a loading platform 1a. FIG. FIG. 2 is a diagram illustrating an example of a functional configuration of a management server 50. FIG. 2 illustrates an example of a hardware configuration of a management server 50. FIG. 2 is a diagram illustrating an example of a functional configuration of a location information server 60. FIG. 7 is a diagram illustrating an example of a functional configuration of a user terminal 70. 11 is a diagram showing an example of a priority identifier stored in a priority identifier storage unit 141. FIG. 11 is a diagram showing an example of an access point identifier acquired by a communication terminal 11a. FIG. 13 is a diagram showing an example of an access point identifier acquired by a communication terminal 11b. FIG. 13 is a diagram showing an example of an access point identifier acquired by a communication terminal 11c. FIG. FIG. 11 is a diagram showing an example of an access point identifier acquired by a communication terminal 11d. FIG. 11 is a diagram showing an example of an access point identifier acquired by a communication terminal 11e. FIG. 13 is a diagram showing an example of an access point identifier acquired by a communication terminal 11f. 11 is a diagram showing an example of a data structure of an upstream message transmitted by each communication terminal 11. FIG. 11 is a diagram showing an example of an upstream message received from each communication terminal 11. FIG. 13 is a diagram showing an example in which a cluster ID is added to an upstream message received from each communication terminal 11. FIG. FIG. 11 is a diagram showing an example of access point identifiers included in each cluster. 11 is a diagram illustrating an example of a table in which access point identifiers are associated with location information of access points. FIG. FIG. 11 is a diagram showing an example of location information estimated as the location of each cluster. 11 is a diagram showing an example of a table in which a warehouse ID, which is identification information of a warehouse, is associated with location information indicating the location of the warehouse. FIG. 13 is a diagram showing an example of information associating the cluster ID of a cluster that matches the location information of a warehouse with the number of communication terminals 11 included in the cluster, that is, the number of containers. FIG. FIG. 13 is a diagram showing an example of clusters extracted as being outside a warehouse and their location information. FIG. 11 is a diagram showing an example of a terminal ID associated with a user ID. 13 is a diagram showing an example of estimated information transmitted from the management server 50 to the user terminal 70. FIG. FIG. 2 is a sequence diagram showing an example of an operation of the position estimation system 100. FIG. 2 is a sequence diagram showing an example of an operation of the position estimation system 100. FIG. 13 is a diagram showing an example of the estimated positions of each loading platform displayed on a map on the display unit 75 of the user terminal 70.

The following describes an embodiment of the present invention with reference to the drawings.

[Overview of location estimation system 100]
The location estimation system 100 shown in FIG. 1 includes, as its components, communication terminals 11a to 11f (hereinafter, collectively referred to as communication terminal 11) installed on multiple loading platforms 1a to 1f (hereinafter, collectively referred to as loading platform 1), a base station 40, a management server 50, a location information server 60, a user terminal device 70, and a network 80.

Access points 30a to 30j (hereinafter collectively referred to as access points 30) are installed inside or around the first warehouse 21 and second warehouse 22, which are collection sites for the loading platform 1. The access points 30 are at the end of the communication network and have the function of accepting connection requests from computers and the like equipped with communication functions and acting as an intermediary between the communication network and the computers and the like. Each of the access points 30 may have a router function, or any one of the multiple access points 30 may have a router function and be connected to the Internet.

The access point 30 has the function of transmitting and receiving wireless signals corresponding to any of the 5 GHz band Wi-Fi standards "11ax, 11ac, 11n/a, 11a" and the 2.4 GHz band Wi-Fi standards "11ax, 11n/g, 11g, 11b." The access point 30 may also be capable of transmitting and receiving wireless signals corresponding to communication standards other than the Wi-Fi standard.

In order to accept connection requests from computers and the like, the access point 30 periodically transmits a wireless signal (also called a beacon) that includes an access point identifier, which is its own identifier. The access point identifier is a MAC address that identifies each individual access point 30.

In addition to the MAC address, any form of information may be used as long as it allows the location information management server 60 (described later) to identify the identification information associated with the location information of the access point 30. For example, an SSID (Service Set Identifier) may be used.

The loading platform 1 moves between each base (first warehouse 21, second warehouse 22, etc.) by being transported by a transport vehicle such as a truck. The loading platform 1 is inside the transport vehicle during transport and is unloaded at each base to which it is moved. Once unloaded, the loading platform 1 remains at the base where it was unloaded for a while. Note that, under normal operation, the loading platform 1 remains at each base or in the transport vehicle, but it is also possible that, under non-normal operation, the loading platform 1 may move to an unexpected location and be left there.

In this embodiment, the rental company owns the loading platform 1. The rental company rents out the loading platform 1 to the user as a service. The user can use the user terminal 70 to display the current position of the rented loading platform 1 on a map screen and grasp the location of the loading platform 1. The rental company can also grasp the location of the loading platform 1 rented to the user by using a rental company terminal (not shown) similar to the user terminal 70.

A user who rents a loading platform 1 may, for example, place a group of multiple loading platforms 1 as loading platform group 10a in the first warehouse 21 shown in FIG. 1 and have them wait there until they load luggage onto the loading platform 1. As shown in FIG. 2, loading platform group 10a is made up of loading platforms 1a, 1b, and 1c stacked together. A communication terminal 11a is mounted on loading platform 1a, a communication terminal 11b is mounted on loading platform 1b, and a communication terminal 11c is mounted on loading platform 1c.

In addition to the group of loading platforms 10a, the group of loading platforms 1d and 1e, which are arranged together in the second warehouse 22 with luggage loaded thereon, such as the group of loading platforms 10b shown in FIG. 1, are also referred to as a "group of loading platforms." Whether multiple loading platforms 1 are arranged together as a group of loading platforms is determined by the clustering process of the management server 50, which will be described later.

In the position estimation system 100, the communication terminal 11 installed in each loading platform 1 periodically transmits an upstream message to the management server 50. The upstream message includes an access point identifier, which is an identifier of a nearby access point 30 acquired by each communication terminal 11.

The management server 50 clusters the uplink messages using the access point identifiers included in the uplink messages received from each communication terminal 11 via the base station 40. The management server 50 presumes that the communication terminals 11 that are the senders of the uplink messages grouped into each cluster are located in approximately the same location.

The management server 50 requests location information on a cluster-by-cluster basis from the location information server 60 using the access point identifiers included in the cluster. The management server 50 counts the number of upstream messages included in the cluster as the number of cargo vehicles. The management server 50 generates the location of the cluster and the number of cargo vehicles included in the cluster as estimated information.

The user terminal 70 can access the management server 50 via the network 80 and log in with a user ID. The user terminal 70 receives estimated information about the cluster that includes the cargo platform 1 rented by the user. Based on the received estimated information, the user terminal 70 displays the location of the cluster and the number of cargo platforms included in the cluster on a map.

The user ID is registered in the management server 50 in a user registration process before using the service. The user registration process is realized by a known process, and is assumed to be, for example, a process of registering and setting a user ID and password.

This allows the user to grasp the locations of multiple rented cargo bins 1 on a cluster basis, making it easier to manage the cargo bins 1. In addition, because location information requests to the location information server 60 are also made on a cluster basis, the amount of location information request processing can be significantly reduced compared to the past. Because the cargo bins 1 are clustered automatically, it is possible to eliminate the need for a person on-site to group and register the cargo bins 1.

The base station 40 has a function of relaying the transmission and reception of wireless signals corresponding to a specified LPWA communication standard between the communication terminal 11 and the management server 50. Although only one base station 40 is illustrated in FIG. 1, multiple base stations 40 exist and cover the transmission and reception of wireless signals in the area in which the loading platform 1 is operated. The base station 40 and the management server 50 are connected via a network 80.

[Configuration of communication terminal 11]
As shown in Fig. 3, the loading platform 1 is equipped with a communication terminal 11. The communication terminal 11 is composed of a communication section 12, a control section 13, and a storage section 14. The communication terminal 11 is equipped with a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory) as hardware configurations. The CPU is also called a central processing unit, central arithmetic unit, processor, microprocessor, microcomputer, or DSP (Digital Signal Processor).

The communication unit 12 includes an acquisition unit 121, a transmission unit 122, and a reception unit 123. The acquisition unit 121 has a function of receiving wireless signals sequentially transmitted from each access point 30 shown in FIG. 1 and acquiring the access point identifier of each access point 30 contained in the wireless signal.

The transmitter 122 has a function of generating and transmitting an upstream message using a radio signal compatible with the LPWA (Low-Power Wide-Area Network) communication standard. The LPWA communication standard includes, for example, SIGFOX (registered trademark) and ELTRES (registered trademark) communication standards that use frequencies in the sub-GHz band (866 MHz band, 915 MHz band, 920 MHz band, etc.). For example, in the case of SIGFOX, there is a limit of 140 transmissions per day per line, and the data size of the payload of an upstream message is limited to 12 bytes.

The receiving unit 123 has a function of receiving a radio signal corresponding to the LPWA communication standard of the transmitting unit 122. For example, in the case of SIGFOX, it is possible to transmit a downstream message from the management server 50 up to four times a day in response to a request from an upstream message. Note that if transmission from the management server 50 to the communication terminal 11 is not performed, the communication terminal 11 does not need to be equipped with the receiving unit 123.

The communication unit 12 may have a function not only to receive a wireless signal transmitted from the access point 30 and obtain an access point identifier, but also to communicate wirelessly with the access point 30.

The control unit 13 has a function of controlling the communication terminal 11. The CPU reads out the programs and data stored in the ROM and uses the RAM as a work area to realize the control of the control unit 13.

The memory unit 14 stores programs and data used by the control unit 13 to perform various processes, as well as data generated or acquired by the control unit 13 as a result of performing various processes.

The hardware of the memory unit 14 is composed of non-volatile semiconductor memory such as flash memory, EPROM (Erasable Programmable ROM), or EEPROM (Electrically Erasable Programmable ROM), or a hard disk drive, etc.

The memory unit 14 stores the access point identifier successively acquired by the acquisition unit 121 in association with the received signal strength indicator (RSSI) value of the wireless signal containing the access point identifier. The memory unit 14 updates and stores the access point identifier each time the acquisition unit 121 acquires a new access point identifier.

The storage unit 14 has a priority identifier storage unit 141 that stores a priority identifier. A priority identifier is an access point identifier that is selected with priority among the access point identifiers sequentially acquired by the acquisition unit 121 and stored in an upstream message.

The priority identifiers may be, for example, "AP2", which is the access point identifier of access point 30b installed in the first warehouse 21, which is the user's distribution base, "AP3", which is the access point identifier of access point 30c, "AP4", which is the access point identifier of access point 30d installed in the second warehouse 22, and "AP5", which is the access point identifier of access point 30e. The priority identifiers may be stored in the priority identifier storage unit 14 in advance, or may be stored in the priority identifier storage unit 141 based on a notification from the management server 50.

[Configuration of management server 50]
4, the management server 50 includes a server communication unit 51, a server control unit 52, a server storage unit 53, and a server display unit 54. The management server 50 is a so-called computer, and includes a CPU, a storage device, and a RAM as hardware. The management server 50 realizes various functional units by the CPU executing a control program stored in the storage device. The management server 50 may be a computer group configured by connecting multiple computers.

The server communication unit 51 has a server receiving unit 511 and a server transmitting unit 512. The server receiving unit 511 has the function of receiving upstream messages from each communication terminal 11 via the base station 40, responses to location requests transmitted from the server transmitting unit 512 to the location information server 60 via the network 80, and estimated information requests transmitted from the user terminal 70.

The server transmission unit 512 has the function of transmitting downstream messages to each communication terminal 11, location requests to the location information server 60, and responses to estimated information requests from the user terminal 70.

The server control unit 52 has a clustering unit 520, a counting unit 521, a position request unit 522, and a position estimation unit 523. The clustering unit 520 has a function of clustering the upstream messages received from each communication terminal 11.

Clustering refers to a method of grouping data based on the similarity between the data. The clustering unit 520 clusters the latest uplink messages received from each communication terminal 11 using a set intersection. The set intersection here refers to grouping uplink messages that contain at least one identical access point identifier into the same group. Specific clustering of uplink messages will be described later.

The counting unit 521 has a function of counting the number of upstream messages clustered by the clustering unit 520. The clustering unit 520 clusters only the latest upstream message received from each communication terminal 11, and since one communication terminal 11 is installed per platform 1, the number of upstream messages represents the number of platforms 1. The counting unit 521 has a function of storing the counted number of platforms in the server storage unit 53 in association with a cluster ID indicating each cluster.

The location request unit 522 has the function of transmitting the access point identifiers included in the cluster from the server transmission unit 512 to the location information server 60 to make a location request.

When the server receiving unit 511 receives location information from the location information server 60 as a response to a location request, the location estimation unit 523 has a function of estimating the location of the cluster based on the received location information. The location estimation unit 523 also has a function of generating estimated information including the estimated cluster location (also called the "estimated location") and the number of bays 1 counted by the counting unit 521, and storing the information in the server storage unit 53.

The server storage unit 53 stores programs and data used by the server control unit 52 to perform various processes, as well as data generated or acquired by the server control unit 52 performing various processes. The server storage unit 53 stores upstream messages received by the server receiving unit 511 from each communication terminal 11, location information received from the location information server 60, and estimated information generated by the location estimation unit 523.

The server storage unit 53 may have a map storage unit 531. The map storage unit 531 stores map information, which is information related to a map. The map information may be, for example, image information of the map. This image information may be, for example, raster data (bitmap data) or vector data.

In addition, if the image information is raster data, the map information may include image information corresponding to multiple scales. For example, the map information may include image information of a large scale, image information of a medium scale, and image information of a small scale for the same area. Furthermore, the map information may represent a map divided into tiles, and by appropriately combining these, it may be possible to display maps of various areas.

Here, the "map" may be a topographical map, a topographical map, a geological map, a land use map, a residential map, a route map, a road map, a guide map, or the like. The map information may also be information that allows a route search to be performed. In other words, the map information may indicate the location of roads. For example, the map information may be in the KIWI format used in car navigation systems.

A "map" may also be an aerial photograph or satellite photograph that allows the viewer to grasp the terrain, roads, etc., or a photograph with symbols, letters, etc. written on it. By displaying based on map information, the user can know the correspondence between each point on the map and its coordinates (location).

The coordinates may be coordinates with a certain reference point as the origin (these coordinates may be distance, for example), or may be latitude and longitude, or other information that can identify a position. The coordinates themselves may be included in the map information. This map information may also include text information related to place names and topographical features such as mountains and rivers. In addition, it is assumed that the direction of a specific direction, such as north, is set in this map information. Note that map information is well known as two-dimensional online maps, electronic maps, etc., and a detailed description thereof will be omitted.

An example of the hardware configuration of the management server 50 will be described with reference to FIG. 5. The management server 50 includes a processor 551, a memory 552, a storage device 553, a communication interface 554, a media connection device 555, an input device 556, and an output device 557. The components of the management server 50 are connected to each other via a bus 550.

The processor 551 executes the program deployed in the memory 552. The storage device 553 stores various information. The storage device 553 may be, for example, a magnetic disk device, an optical disk device, a magneto-optical disk device, a tape device, a hard disk drive, or a flash memory.

The management server 50 can load the programs and data stored in the storage device 553 into the memory 552 for use. The storage device 553 may store information processing programs relating to the processing performed by each functional unit of the management server 50. The storage device 553 can be used as the management server storage unit 53 described above.

The communication interface 554 can be connected, for example, by wire or wirelessly, to a communication network such as a LAN (Local Area Network) or a WAN (Wide Area Network). The communication interface 554 is connected, for example, to the network 80, and performs data conversion associated with communication.

The management server 50 can load into the memory 552 and use the programs and data received from the external device via the communication interface 554. The communication interface 554 can be used as the server communication unit 51 of the management server 50.

The medium connection device 555 is an interface that can be connected to the portable recording medium 558. The medium connection device 555 is configured so that it can be connected to or separated from the portable recording medium 558. The medium connection device 555 accesses the recorded contents of the portable recording medium 558.

The portable recording medium 558 is, for example, a semiconductor memory, a flexible disk, an optical disk, or a magneto-optical disk. The portable recording medium 558 may be, for example, a CD-ROM (Compact Disk Read Only Memory), a DVD (Digital Versatile Disk), or a USB (Universal Serial Bus) memory.

The management server 50 can load the programs and data stored in the portable recording medium 558 into the memory 552 and use them. The portable recording medium 558 may store information processing programs related to the processing performed by each functional unit of the management server 50.

Memory 552, storage device 553, and portable recording medium 558 are tangible recording media that can be read by a computer. Memory 552, storage device 553, and portable recording medium 558 are non-transient recording media, not transitory media such as signal carrier waves.

The input device 556 is configured to be able to accept input of instructions and information from a user. Examples of the input device 556 include a touch panel, a keyboard, and a mouse.

The output device 557 is configured to be able to output inquiries or instructions to the user and processing results. Examples of the output device 557 include a display unit, a speaker, or a printer. Examples of the display unit include a liquid crystal display device and an organic EL (Electro Luminescence) display device.

The management server 50 may not include all of the hardware components shown in FIG. 5. The management server 50 may omit some of the hardware components depending on the application or conditions. For example, if the portable recording medium 558 is not used, the management server 50 may omit the medium connection device 555.

In addition, when some of the hardware configuration of the management server 50 exists in a device external to the management server 50, the management server 50 may connect to the external device and use the components of the external device. In other words, the management server 50 may process each process or function by a single device or a single system, or may perform distributed processing by multiple devices or multiple systems.

The hardware configuration shown in FIG. 5 can be used as the hardware configuration of the location information server 60 and the user terminal 70, as well as the management server 50.

[Configuration of location information server 60]
6, the location information server 60 includes a location information server communication unit 61, a location information server control unit 62, and a location information storage unit 63. The location information server 60 is a so-called computer, and includes, as hardware, a processor 551, a memory 552, a storage device 553, a communication interface 554, and an output device 557 shown in FIG.

The location information server 60 realizes various functional sections by the CPU executing the control program stored in the storage device 553.

The communication interface 554 shown in FIG. 5 can be used as a location information server communication unit 61, the processor 551 can be used as a location information server control unit 62, and the storage device 553 can be used as a location information storage unit 63.

The location information server communication unit 61 has the function of receiving a location request sent from the management server 50 via the network 80 and sending the location information extracted from the location information storage unit 63 to the management server 50.

The location information server control unit 62 has a function of extracting associated location information from the location information storage unit 63, which stores the access point identifier and the location information of the access point 30 in association with each other, based on the access point identifier included in the received location request.

The location information storage unit 63 has a function of storing an access point identifier in association with location information indicating the location of the access point. Since the installation location of an access point may change, the location information of the access point stored in the location information storage unit 63 may have a function of periodically updating the access point identifier.

[Configuration of user terminal 70]
7, the user terminal 70 includes an input unit 71, a user terminal control unit 72, a user terminal communication unit 73, a user terminal storage unit 74, and a display unit 75. The user terminal 70 is a so-called computer, and includes, as hardware, a processor 551, a memory 552, a storage device 553, a communication interface 554, an input device 556, and an output device 557 shown in FIG.

The user terminal 70 realizes various functional units by the processor 551 executing the control program stored in the storage device 553.

The input device 556 shown in FIG. 5 can be used as the input unit 71, the processor 551 can be used as the user terminal control unit 72, the communication interface 554 can be used as the user terminal communication unit 73, the storage device 553 can be used as the user terminal storage unit 74, and the output device 557 can be used as the display unit 75.

The input unit 71 has a function of accepting a loading platform position display instruction, which is an instruction to display the current position of each loading platform 1 being operated on a map, by a user operation.

The user terminal control unit 72 has a function of requesting the management server 50 for estimated position information of the loading platform 1 associated with the user ID based on the loading platform position display instruction received by the input unit. The request for estimated position information includes the user ID.

The user terminal communication unit 73 has a function of sending a request including a user ID to the management server 50 and receiving a response from the management server 50. The response from the management server 50 is estimated location information of the cluster that includes the loading platform 1 associated with the user ID.

The user terminal storage unit 74 has a user map storage unit 741. The user map storage unit 741 stores user map information indicating a map of the range operated by the user, among the map information described above. The user map information may be stored in advance in the map storage unit 741, or the latest user map information may be obtained and stored by using a service that provides map information.

The display unit 75 has a function of displaying a map based on the user map information stored in the map storage unit 741, and displaying the position of each cluster indicated by the estimated position information and the number of cargo bays included in the cluster on the map by superimposing them on the map.

[Upstream message]
The uplink messages transmitted by each communication terminal 11 will be described with reference to Fig. 8 to Fig. 15. As shown in the example of Fig. 8, the access point identifier "AP2" of the access point 30b, the access point identifier "AP3" of the access point 30c, the access point identifier "AP4" of the access point 30d, and the access point identifier "AP5" of the access point 30e are stored as priority identifiers in the priority identifier storage unit 141 of each communication terminal 11.

Next, the access point identifiers that are successively updated and stored in the memory unit 14 of each communication terminal 11 will be described. As shown in FIG. 9, the memory unit 14 of communication terminal 11a stores a predetermined number of access point identifiers successively acquired by the acquisition unit 121 in descending order of the RSSI value of the carrier radio waves of the access point identifiers. Each time the acquisition unit 121 successively acquires an access point identifier, the control unit 13 of communication terminal 11a updates and stores the access point identifier stored in the memory unit 14 in association with the RSSI value.

In the access point identifier acquisition state shown in FIG. 9, the control unit 13 of the communication terminal 11a refers to the priority identifier stored in the priority identifier storage unit 141. The control unit 13 selects AP2 and AP3 that match the priority identifier, stores them in the payload of the upstream message, and causes the transmission unit 122 to transmit it.

If there is no access point identifier that matches the priority identifier among the multiple access point identifiers acquired, the control unit 13 selects two access point identifiers in descending order of RSSI value.

In the access point identifier acquisition state shown in FIG. 10, the control unit 13 of the communication terminal 11b refers to the priority identifier stored in the priority identifier storage unit 141. The control unit 13 does not select AP1 with the highest RSSI value, but selects AP3 and AP2 with matching priority identifiers, stores them in the payload of the uplink message, and causes the transmission unit 122 to transmit the uplink message.

In the access point identifier acquisition state shown in FIG. 11, the control unit 13 of the communication terminal 11c refers to the priority identifier stored in the priority identifier storage unit 141, selects AP3 and AP2 that match the priority identifier, stores them in the payload of the upstream message, and causes the transmission unit 122 to transmit the upstream message.

In the access point identifier acquisition state shown in FIG. 12, the control unit 13 of the communication terminal 11d refers to the priority identifier stored in the priority identifier storage unit 141, selects AP5 that matches the priority identifier and AP6 that has a high RSSI value, stores them in the payload of the uplink message, and causes the transmission unit 122 to transmit the uplink message.

In the access point identifier acquisition state shown in FIG. 13, the control unit 13 of the communication terminal 11e refers to the priority identifier stored in the priority identifier storage unit 141, selects AP4 and AP5 that match the priority identifier, stores them in the payload of the upstream message, and causes the transmission unit 122 to transmit the upstream message.

In the access point identifier acquisition state shown in FIG. 14, the control unit 13 of the communication terminal 11f refers to the priority identifier stored in the priority identifier storage unit 141, but since there is no access point identifier that matches the priority identifier, it selects AP8 and AP7 in descending order of RSSI value, stores them in the payload of the uplink message, and causes the transmission unit 122 to transmit the uplink message.

As shown in FIG. 15, an upstream message consists of a 10-byte header, a maximum 12-byte payload, and a 4-byte footer. The payload consists of a 6-byte first access point identifier and a 6-byte second access point identifier. If two access point identifiers cannot be selected, or if none can be selected, a NULL value is stored.

The 10-byte header contains a terminal ID (4 bytes) that identifies the communication terminal 11. The 4-byte footer contains an authentication code, HMAC (Hash-based Message Authentication Code), and an error detection code, CRC (Cyclic Redundancy Check).

[Operation of the location estimation system 100]
The operation of the location estimation system 100 will be described with reference to Fig. 16 to Fig. 27. As shown in Fig. 16, the server storage unit 53 updates and stores the latest upstream message upon receiving an upstream message from each communication terminal 11. The upstream message includes a terminal ID, a first access point identifier, and a second access point identifier.

In FIG. 16, the terminal ID "11aa" is the terminal ID of communication terminal 11a. The terminal ID "11bb" is the terminal ID of communication terminal 11b. The terminal ID "11cc" is the terminal ID of communication terminal 11c. The terminal ID "11dd" is the terminal ID of communication terminal 11d. The terminal ID "11ee" is the terminal ID of communication terminal 11e. The terminal ID "11ff" is the terminal ID of communication terminal 11f.

An upstream message containing the terminal ID "11aa" contains "AP2" as the first access point identifier and "AP3" as the second access point identifier. An upstream message containing the terminal ID "11bb" contains "AP3" as the first access point identifier and "AP2" as the second access point identifier. An upstream message containing the terminal ID "11cc" contains "AP3" as the first access point identifier and "AP2" as the second access point identifier.

An upstream message containing the terminal ID "11dd" contains "AP5" as the first access point identifier and "AP6" as the second access point identifier. An upstream message containing the terminal ID "11ee" contains "AP4" as the first access point identifier and "AP5" as the second access point identifier. An upstream message containing the terminal ID "11ff" contains "AP8" as the first access point identifier and "AP7" as the second access point identifier.

As shown in FIG. 17, the clustering unit 520 adds the same cluster ID "1" to the upstream message shown in FIG. 16 including the terminal ID "11aa", the upstream message including the terminal ID "11bb", and the upstream message including the terminal ID "11cc", because they all include the common access point identifiers "AP2" and "AP3".

In addition, because the upstream message containing the terminal ID "11dd" and the upstream message containing the terminal ID "11ee" contain a common access point identifier "AP5", the clustering unit 520 assigns the same cluster ID "2" to them and clusters them.

Since the upstream message containing the terminal ID "11ff" does not share an access point identifier with other upstream messages, the clustering unit 520 assigns the cluster ID "3" to it alone.

The clustering unit 520 extracts the access point identifiers contained in the upstream messages of each cluster from the upstream messages to which the cluster IDs have been added.

As shown in FIG. 18, the cluster with cluster ID "1" includes the access point identifiers "AP2" and "AP3". The cluster with cluster ID "2" includes the access point identifiers "AP4", "AP5", and "AP6". The cluster with cluster ID "3" includes the access point identifiers "AP7" and "AP8".

The management server 50 makes a location request to the location information server 60 on a cluster-by-cluster basis. For example, in a location request for a cluster with cluster ID "1", the management server 50 sends the access point identifiers "AP2" and "AP3" to the location information server 60 as location request information.

The location information server 60 receives the location request information sent from the management server 50, and determines the location information to respond to based on the access point identifier included in the location request information. For example, if the access point identifiers included in the location request information are "AP1", "AP2", and "AP3", the location information may be determined by calculating the position that is the center of gravity of the location information associated with each access point identifier, or the location information may be determined using another algorithm.

The location information server 60 responds with the determined location information to the management server 50. Note that although the location information shown in FIG. 19 is expressed in latitude and longitude, other expressions may be used as long as the information can identify the location. For example, the location information may be converted to location information expressed in a planar rectangular coordinate system, in which the data size is smaller than that of latitude and longitude.

As shown in FIG. 20, the management server 50 stores the location information received from the location information server 60 in the server storage unit 53.

The management server 50 also stores warehouse location information in the server storage unit 53, as shown in FIG. 21, which associates a warehouse with location information of the warehouse. For example, the warehouse ID "211", the warehouse name "First Warehouse 21", and location information "(35.16938, 135.36163)" are associated with the warehouse location information.

When the cluster-based location information responded from the location information server 60 roughly matches the warehouse location information shown in FIG. 21, the location estimation unit 523 may estimate the warehouse location information as the location of the cluster, assuming that the cluster is located in the matching warehouse. When the cluster-based location information does not match the warehouse location information shown in FIG. 21, the location estimation unit 523 may estimate that the location indicated by the location information is the location of the cluster.

As shown in FIG. 22, the management server 50 may store in the server storage unit 53 the cluster ID of the cluster that matches the warehouse location information, the number of communication terminals 11 included in the cluster, i.e., the number of loading bins, the warehouse ID, and the terminal IDs included in the cluster, in association with each other.

In the example shown in FIG. 22, for example, cluster ID "1" is associated with the number of bins "3" counted by the counting unit 521, warehouse ID "211," and terminal IDs "11aa," "11bb," and "11cc."

For clusters that do not match the warehouse location information, the management server 50 may store them in the server storage unit 53 as clusters outside the warehouse, as shown in FIG. 23, by associating the cluster ID, the terminal IDs included in the cluster, and the location information.

In the example shown in FIG. 23, cluster ID "3" includes one loading platform 1. The terminal ID of the communication terminal 11 installed on loading platform 1 is "11ff", which indicates that it is located at latitude: 35.16938, longitude: 135.36163.

As shown in FIG. 24, the management server 50 stores in the server storage unit 53 information associating the user ID of a user who uses the rental service of the loading platform 1 with the terminal ID of the communication terminal 11 installed on each loading platform 1 rented to the user.

In the example shown in FIG. 24, the terminal IDs "11aa", "11bb", "11cc", etc. of the communication terminals installed on the rented cargo bed 1 are stored in the server storage unit 53 in association with the user ID "311". Information associating the user ID with the terminal ID may be generated by the service provider through a registration procedure when the user rents the cargo bed.

The management server 50 may further store in the server storage unit 53, as shown in FIG. 25, estimated information including the user ID, the number of containers in the cluster that includes the terminal ID associated with the user ID, and location information of the cluster.

Next, the process performed by each device included in the position estimation system 100 and the flow of communication between the devices will be explained using the sequence diagrams shown in Figs. 26 and 27. Note that the symbol "S" in Figs. 26 and 27 means a step.

First, as shown in FIG. 26, each communication terminal 11 acquires multiple access point identifiers from radio waves wirelessly transmitted by each surrounding access point 30 (S1). Each communication terminal 11 updates and stores the most recent acquired access point identifier in the memory unit 14 (S2).

When a predetermined time has elapsed (S3: Yes), each communication terminal 11 selects an access point identifier that matches the priority identifier, or if there is no match, selects up to two access point identifiers with large RSSI values, stores them in the payload of an uplink message, and transmits them (S4). After transmitting the uplink message, each communication terminal 11 returns to the processing of S1.

If the predetermined time has not elapsed in the process of S3 (S3: No), each communication terminal 11 returns to S1.

When the management server 50 receives an upstream message from each communication terminal 11 (S5: Yes), it updates the upstream message successively to the latest one and stores it in the server storage unit 53 (S6). The clustering unit 520 clusters the upstream messages stored in the server storage unit 53 (S7).

The management server 50 transmits the access point identifiers contained in each cluster to the location information server 60 and makes a location request (S8).

When the location information server 60 receives an access point identifier as a location request from the management server 50 (S9: Yes), it extracts location information associated with the access point identifier included in the received location request (S10). The location information server 60 transmits the extracted location information to the management server 50 (S11). After transmitting the location information to the management server 50, the location information server 60 returns to the processing of S9.

As a result of the location request made in the process of S8, the management server 50 receives a response from the location information server 60 (S12). Based on the location information included in the response, the management server 50 generates estimated information including the estimated location of the cluster and the number of cargo bays (S13). After performing the process of S13, the management server 50 returns to S5.

As shown in FIG. 27, when the user terminal 70 receives an instruction from the user to display the loading platform position (S14: Yes), it transmits the user ID to the management server 50 and requests estimated information (S15).

When the management server 50 receives an estimated information request including a user ID from the user terminal 70 (S16: Yes), the management server 50 responds to the request from the user terminal 70 by transmitting estimated information of the cluster including the terminal ID associated with the user ID (S17). After that, the management server 50 returns to the processing of S16.

The user terminal 70 receives a response to the estimated information request from the management server 50 (S18). The user terminal 70 displays the loading platform positions and the number of loading platforms based on the received estimated information (S19). The user terminal 70 then returns to the process of S14.

As shown in the example of FIG. 28, the user terminal 70 displays a screen 90 on the display unit 75 showing the locations of the loading bays and the number of loading bays on a map based on the received estimated information. On the screen 90, a warehouse icon 91 and a first window 92 are displayed at the corresponding location on the map showing the location of the second warehouse 22. The first window 92 displays "Second warehouse" and "Number of loading bays: 2".

For clusters that do not match the location of the warehouse, a loading platform icon 93 and a second window 94 are displayed at the corresponding location on the map where the cluster is located as a loading platform outside the warehouse. The second window 94 displays "loading platform outside the warehouse", "number of loading platforms: 1", and "terminal ID: 11ff".

The user can check the screen 90 to ascertain which pallets are in the warehouse and which are outside the warehouse. In addition, the user can automatically group accumulated pallets and ascertain the location of the pallets by group without having to assign a management worker to the site according to the present invention.

The present invention is not limited to the above-described embodiments, but should be understood as including various modifications and alternative forms of the above-described embodiments. For example, the present invention includes embodiments in which the components are modified without departing from the spirit and scope of the present invention, embodiments in which multiple components disclosed in the above-described embodiments are appropriately combined, and embodiments in which some components are deleted from all the components shown in the embodiments, or some components are added to the components shown in the embodiments.

For example, the information that associates the access point identifiers and the location information of the access points stored in the location information server 60 is a so-called database, and the management server 50 or the user terminal 70 may be provided with such a database function to realize the present invention.

In the above embodiment, the present invention is applied to a system in which a communication terminal 11 is installed in the loading platform 1 and the current position of the loading platform 1 is managed, but the present invention is not limited to this. For example, the present invention can be applied to managing the current position of a moving object such as a vehicle by installing the communication terminal 11 therein. The present invention can also be applied to managing the position of items for sale or rental items (electronic devices, etc.) that require tracking. Furthermore, the present invention may be a cluster position estimation method.

In the above embodiment, for example, if there are multiple groups of loading bins 10 in the same warehouse and the groups of loading bins 10 are placed close to each other, it is assumed that the communication terminals 11 installed on each loading bin 1 will acquire the access point identifier of the same access point 30 in the vicinity. As a result, each communication terminal 11 will transmit an upstream message including the same access point identifier to the management server 50, and it is assumed that the management server 50 will distinguish each group of loading bins 10 as being part of the same cluster, rather than as separate clusters.

Here, if a user wishes to manage each group of cargo bays 10 as a separate group, the communication terminal 11 may be equipped with a WPAN (Wireless Personal Area Network) communication function such as BLE (Bluetooth Low Energy), so that each group of cargo bays 10 placed in the same warehouse can be identified as a separate cluster.

For example, each communication terminal 11 equipped with a BLE communication function transmits radio waves including an identifier (which may be the above-mentioned terminal ID) that identifies itself, and receives radio waves transmitted by other communication terminals 11, thereby enabling each communication terminal 11 to obtain the identifiers of the other communication terminals 11. Each communication terminal 11 stores the RSSI value of the radio waves received from the other communication terminals 11 in association with the obtained identifier. Each communication terminal 11 selects only multiple identifiers with high RSSI values (e.g., three), stores them in the payload of an upstream message, and transmits them to the management server 50.

The management server 50 can estimate the cluster of multiple cargo platforms 1 on which each communication terminal 11 is installed, i.e., the group of cargo platforms 10, by clustering using the identifiers contained in the upstream messages received from each communication terminal 11.

Each program described in the above embodiment may be provided in the following form for another computer having a hardware configuration equivalent to that shown in FIG.
(1) Provided by pre-installing it in the storage device 553.
(2) Provided via portable recording medium 558.
(3) The communication interface 554 downloads and provides a program from a program server.

1 Loading platform 10 Loading platform group 11 Communication terminal 12 Communication unit 13 Control unit 14 Memory unit 21 First warehouse 22 Second warehouse 30 Access point 40 Base station 50 Management server 51 Server communication unit 52 Server control unit 53 Server memory unit 54 Server display unit 60 Position information server 61 Position information server communication unit 62 Position information server control unit 63 Position information server memory unit 70 User terminal 71 Input unit 72 User terminal control unit 73 User terminal communication unit 74 User terminal memory unit 75 Display unit 80 Network 90 Screen 91 Warehouse icon 92 First window 93 Loading platform icon 94 Second window 100 Position estimation system 121 Acquisition unit 122 Transmission unit 123 Reception unit 141 Priority identifier memory unit 511 Server reception unit 512 Server transmission unit 520 Clustering unit 521 Counting unit 522 Position request unit 523 Position estimation unit 531 Map memory unit 550 Bus 551 Processor 552 Memory 553 Storage device 554 Communication interface 555 Media connection device 556 Input device 557 Output device 558 Portable recording medium 741 User map storage unit

Claims (7)

A location estimation system including: a plurality of communication terminals each successively transmitting a message including an identifier of one or more acquired access points and a terminal ID for identifying each communication terminal to a management server; the management server; and a location information server that stores location information indicating the locations of the access points in association with the identifiers,
The management server includes:
a server receiving unit for receiving the messages successively transmitted from a plurality of the communication terminals;
a server storage unit that successively updates and stores the message for each terminal ID;
a clustering unit that clusters a plurality of the messages into clusters based on the identifiers included in the stored messages;
a location request unit that transmits the identifier included in the cluster to the location information server and requests the location information associated with the identifier;
a location estimation unit that receives the location information transmitted from the location information server, and estimates the location indicated by the location information as an estimated location of the communication terminal that is the sender of the message and is included in the cluster. The position estimation system further comprises:
a map storage unit that stores map information representing a map;
a display unit that displays the map based on the map information and displays an icon indicating the cluster on the displayed map in a superimposed manner at the estimated position.
2. The position estimation system according to claim 1 . The position estimation system further comprises:
a counting unit that counts the number of the messages included in the cluster as the number of the communication terminals;
The display unit displays the number counted by the counting unit by superimposing it on the map.
3. The position estimation system according to claim 2. The location estimation system further includes a user terminal;
The user terminal,
The map storage unit;
The display unit;
a user terminal communication unit for receiving estimated information including the estimated position from the management server;
4. The position estimation system according to claim 2 or 3. The communication terminal includes:
an acquisition unit that receives signals including the identifier from a plurality of the access points that wirelessly transmit the signals and sequentially acquires the identifier;
A storage unit that stores the identifier;
a priority identifier storage unit that stores a priority identifier indicating the identifier to be selected with priority;
a transmission unit that selects, from among the identifiers, identifiers that match the priority identifier, and sequentially transmits the message including a predetermined number of the identifiers and the terminal ID to the management server;
5. A position estimation system according to claim 1, wherein the position estimation system comprises: The communication terminal is installed on a loading platform or a moving body,
The position estimation unit estimates a position of the loading platform or the moving object.
6. A position estimation system according to claim 1, wherein the position estimation system comprises: receiving messages from a plurality of communication terminals, the messages including identifiers of one or a plurality of access points and terminal IDs for identifying each communication terminal;
The message is successively updated and stored for each of the terminal IDs;
clustering the stored messages into clusters based on the identifiers included in the messages;
extracting, from a database that stores location information indicating a location of the access point and the identifier of the access point in association with each other, the associated location information by using the identifier included in the cluster;
Estimating the location indicated by the extracted location information as the location of the communication terminal that is included in the cluster and is the source of the message;
2. A cluster location estimation method comprising:

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