Location management system

Abstract

To provide a wireless transmitter location management system that is inexpensive, can cover a wide area over a long period of time. [Solution] The location management system 1 comprises a wireless transmitter 2, a repeater 3, and a server 5, as described below. The wireless transmitter 2 transmits individual signals containing individual information at predetermined time intervals. The repeater 3 acquires location information at predetermined time intervals and transmits identified location information, which is the location information with identification information attached, at predetermined time intervals. The server 5 receives and stores the identified location information transmitted from the repeater 3. The repeater 3 includes a mobile unit and has a receiving unit 7 that receives individual signals. When it receives an individual signal, it acquires the signal strength of the individual signal, stores the maximum strength value (the maximum value of the signal strength) and the time at which it occurred, and transmits supplementary data with the individual information, maximum strength value, and maximum strength time attached to the identified location information. The server 5 calculates the wireless transmitter location from the supplementary data.

Description

Technical Field

[0001] The present disclosure relates to a position management system, and in particular to a position management system for wireless transmitters including mobile objects in repeaters.

Background Art

[0002] In recent years, position information providing services using GNSS (Global Navigation Satellite System) satellites have been commonly used. Accordingly, as a position management system for wireless transmitters, a configuration in which a GNSS positioning unit is mounted on a wireless transmitter is conceivable. However, since the power consumption when using GNSS satellites is high, the limit for incorporating a GNSS positioning unit into a small wireless transmitter to acquire and transmit position information at predetermined intervals is about several days due to the limited power supply capacity. As a result, long-term operation of the wireless transmitter position management system becomes difficult.

[0003] Accordingly, as a position management system that reduces the power consumption of wireless transmitters, a position management system based on a gate check method using receivers installed at specific gates is conceivable. However, since the configuration can only check passage through specific gates, it cannot be said to be a configuration suitable for wide-range position management.

[0004] Furthermore, position management systems for wireless transmitters that use Bluetooth (registered trademark) are also known. In such a position management system, it is common to determine whether a wireless transmitter has deviated from a predetermined route by judging whether the wireless transmitter has passed near a repeater (base station terminal) arranged on the predetermined route (see, for example, Patent Document 1).

[0005] However, in the configuration of Patent Document 1, the relay unit is fixed or semi-fixed, so it can only handle pre-set routes and lacks significant flexibility as a position management system for wireless transmitters.

[0006] Furthermore, because Bluetooth® uses the 2.4GHz high-frequency band, the radio waves have high directivity, preventing them from penetrating behind obstacles. As a result, the effective transmission range of a wireless transmitter is limited to only a few meters to a dozen meters. Therefore, to cover a wide area, it is necessary to increase the number of relay devices, which leads to the problem of high implementation costs for building a location management system. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 5891468 [Overview of the project] [Problems that the invention aims to solve]

[0008] This disclosure is made to solve the above-mentioned problems, and its purpose is to provide a wireless transmitter position management system that can cover a wide area in a low cost and over a long period of time. [Means for solving the problem]

[0009] The location management system disclosed herein comprises a wireless transmitter, a repeater, and a server, as described below. The wireless transmitter transmits individual signals containing specific information at predetermined time intervals. The relay device acquires location information at predetermined time intervals and transmits identified location information, which is the location information with identification information attached, at predetermined time intervals. The server receives and stores the identification location information transmitted from the relay device.

[0010] Here, the relay unit includes a mobile unit and has a receiving unit that receives individual signals. Then, upon receiving an individual signal, the signal strength of that individual signal is acquired, and the maximum intensity value (the maximum value of the signal strength) and the time at which it occurred are stored. At the same time, supplementary data containing the individual information, the maximum intensity value, and the maximum intensity time is transmitted along with the identification location information. The server also calculates the location of the wireless transmitter from the accompanying data.

[0011] Since the wireless transmitter does not acquire location information and only transmits individual signals for short periods at predetermined intervals, power consumption can be suppressed and the transmission state can be maintained for extended periods. Furthermore, since the repeater includes a mobile unit and has a receiving section that receives individual signals, it becomes possible to cover a wide area with fewer repeaters.

[0012] Furthermore, since location information is acquired using a relay device with relatively ample power capacity, it is possible to maintain reception for extended periods. Furthermore, since the repeater only stores the maximum signal strength value and time, it does not put a strain on memory capacity even if the number of wireless transmitters increases. Therefore, the storage capacity of the repeater can be kept small, and the cost of the repeater can be reduced.

[0013] In other words, wireless transmitters with limited power capacity are assigned only to low-power transmissions, while a small number of repeaters with ample power capacity are used to acquire high-power location information over a wide area, thereby indirectly determining the location of the wireless transmitters. This makes it possible to provide a wireless transmitter location management system that is inexpensive, can cover a wide area over a long period of time, and can be provided at a low cost. [Brief explanation of the drawing]

[0014] [Figure 1] This is an explanatory diagram of the location management system (Example 1). [Figure 2] This is an explanatory diagram illustrating a specific example of how a server calculates the position of a wireless transmitter (Example 1). [Figure 3] This is an explanatory diagram of a position management system (Example 2). [Figure 4] This is an explanatory diagram of a specific example of the method for calculating the position of a wireless transmitter by a server (Example 2). [Mode for Carrying Out the Invention]

[0015] Hereinafter, modes for carrying out the present disclosure will be described based on examples. Note that the following examples disclose specific illustrative instances, and it goes without saying that the present disclosure is not limited to the following examples. [Examples]

[0016] [Configuration of Example 1] The configuration of the position management system 1 according to Example 1 will be described using Figure 1. The position management system 1 includes a wireless transmitter 2, a relay device 3, and a server 5, which are described below. The wireless transmitter 2 transmits individual signals at predetermined time intervals.

[0017] Here, the individual signals transmitted by the wireless transmitter 2 use a specified low-power band that complies with the Radio Act of Japan. More specifically, the individual signals transmitted by the wireless transmitter 2 are formed by superimposing individual information on a 920 MHz carrier wave. The wireless transmitter 2 is carried by a pedestrian p, and transmits the individual signals for 10 ms at 10-second intervals. Note that since the wireless transmitter 2 is a position management target of the position management system 1, it preferably includes direct or indirect unique information that can identify the wireless transmitter 2 as the individual information.

[0018] In addition, since the wireless transmitter 2 only transmits individual signals, it has a simple structure and can be easily miniaturized. Furthermore, since the transmission period is as short as 10 ms, power consumption is low, and continuous operation for several months is possible using a built-in power supply (such as a secondary battery).

[0019] The relay device 3 acquires location information at predetermined time intervals and transmits identified location information, which is the location information with identification information attached, at predetermined time intervals. Server 5 then receives and stores the identification location information transmitted from relay device 3. Here, the repeater 3 is a mobile unit and has a receiving unit 7 that receives individual signals. Furthermore, since relay unit 3 only needs to be distinguishable from other relay units 3, the identification information can be highly anonymous and does not include any unique information about relay unit 3.

[0020] More specifically, the relay unit 3 has a GNSS positioning unit (not shown) and acquires position information using GNSS satellites at 10-minute intervals, and transmits identified position information, which is the acquired position information with identification information attached, at 10-minute intervals. Server 5 then receives identification location information transmitted by relay device 3 via the internet line i at 10-minute intervals, and stores the reception time and the location information of relay device 3.

[0021] Here, relay unit 3 is a mobile unit. More specifically, the relay unit 3 is fixed to a moving medium v ​​such as a bus or automobile, and is a moving object whose position is displaced as the moving medium v ​​moves.

[0022] Furthermore, the repeater 3 has a receiving unit 7 that receives individual signals. The receiving unit 7 receives individual signals, decodes them, and extracts individual information. Furthermore, when an individual signal is received, it acquires the signal strength of that signal.

[0023] Furthermore, the repeater 3 has a storage unit 8 that stores individual information, signal strength, and the time at which the individual signal was acquired. When a new individual signal for the same individual information is received, it is compared with the signal strength stored in the memory unit 8. If the new signal strength exceeds the value stored in the memory unit 8, the signal strength and the time the signal was acquired are overwritten. As a result, the memory unit 8 stores, for each individual piece of information, the maximum intensity value, which is the maximum value of the signal intensity, and the maximum intensity time, which is the maximum value of the signal intensity.

[0024] Furthermore, the relay unit 3 has a transmitting unit 10 that transmits identification location information at 10-minute intervals. When the relay unit 3 receives an individual signal, that is, when individual information is stored in the memory unit 8, it transmits supplementary data, which includes the maximum intensity value and maximum intensity time for each piece of individual information, to the server 5 via the internet line i from the transmission unit 10. Furthermore, after the supplementary data is sent to the server 5 via the transmission unit 10, the data in the storage unit 8 is reset by zeroing it out or the like.

[0025] Server 5 calculates the position of wireless transmitter 2 from the accompanying data. The server 5 is equipped with a display unit 11 that displays the location of the wireless transmitter 2. Server 5 is configured to include a well-known microcomputer having a CPU or GPU with computing functions, various storage devices such as ROM and RAM, input devices, and output devices, and is constantly connected to the Internet line i.

[0026] Here, a specific example of how server 5 calculates the position of wireless transmitter 2 will be explained using Figure 2. For example, consider the case where the location information transmitted by relay device 3 is 10:00:00:00 for A and 10:10:00:00 for B. Furthermore, we assume that the individual information of the supplementary data at 10:10:00:00, the maximum intensity value, and the time of maximum intensity are as shown in Table 1.

[0027] [Table 1]

[0028] The propagation loss (Loss(dB)) corresponding to the maximum signal strength at a distance d(m) from a transmitter of frequency f(MHz) is expressed by the following equation (1).

number

[0029] In Figure 2, first, a straight line is drawn connecting points A and B, and the movement of the repeater 3 over 10 minutes is approximated as a straight line at a constant velocity. Next, a circular region corresponding to the maximum intensity value (-70dB) is set centered on position α, which corresponds to the time of maximum intensity of individual information α (10:03:35:50), and this circular region is defined as the area where the wireless transmitter 2 equipped with identification information α at the time of maximum intensity is located. Similarly, a circular region corresponding to the maximum intensity value (-80dB) is set centered on position β, which corresponds to the time of maximum intensity of individual information β (10:08:40:80), and this circular region is defined as the area where the wireless transmitter 2 containing the identification information β at the time of maximum intensity is located.

[0030] The server 5 then displays the location of each wireless transmitter 2 on the display unit 11, as shown in Figure 2, on map information (not shown). The display unit 11 may be attached to the server 5, or it may be displayed remotely via the internet connection i.

[0031] [Effects of Example 1] The location management system 1 disclosed herein comprises a wireless transmitter 2, a repeater 3, and a server 5, as described below. Wireless transmitter 2 transmits individual signals containing individual information at 10s intervals. Repeater 3 acquires location information at 10-minute intervals and transmits identified location information, which is the location information with identification information attached, at 10-minute intervals. Server 5 receives and stores the identification location information transmitted from relay device 3.

[0032] Here, the repeater 3 is a mobile unit and has a receiving unit 7 that receives individual signals. Then, upon receiving an individual signal, the signal strength of that individual signal is acquired, and the maximum intensity value (the maximum value of the signal strength) and the time at which it occurred are stored. At the same time, supplementary data containing the individual information, the maximum intensity value, and the maximum intensity time is transmitted along with the identification location information. Server 5 also calculates the position of the wireless transmitter from the accompanying data.

[0033] Since the wireless transmitter 2 does not acquire location information and only transmits individual signals for short periods at predetermined intervals, power consumption can be suppressed and the transmission state can be maintained for a long period of time. Furthermore, since the repeater 3 is a mobile unit fixed to the mobile medium v ​​and has a receiving unit 7 that receives individual signals, it is possible to cover a wide area with a small number of repeaters 3.

[0034] Furthermore, since location information is acquired using repeater 3, which has relatively ample power capacity, it is possible to maintain reception for extended periods. Furthermore, since the repeater 3 only stores the maximum signal strength value and the time of maximum signal strength, it does not put a strain on the memory capacity even if the number of wireless transmitters 2 increases. Therefore, the storage capacity of the repeater 3 can be kept small, and the cost of the repeater 3 can be reduced. This makes it possible to provide a wireless transmitter 2 position management system 1 that can cover a wide area over a long period of time at a low cost.

[0035] [Configuration of Example 2] The position management system 1 of Example 2 will be explained using Figure 3, focusing on the differences from the position management system 1 of Example 1. In the location management system 1 of Example 2, the moving medium v ​​has other location information acquisition devices 20 (for example, a car navigation system).

[0036] Here, the location information acquisition device 20 has a GNSS positioning unit (not shown) and acquires location information using GNSS satellites at 1-second intervals, and stores the location information and the location information acquisition time in the storage unit 21 for a predetermined period. Furthermore, the location information acquisition device 20 and the relay device 3 have their time synchronized in advance using a time server or the like.

[0037] When transmitting identification location information, the relay device 3 refers to the storage unit 21 of the location information acquisition device 20 and further adds the previous time, previous location information, next time, and next location information to the accompanying data. Here, the "immediate time" refers to the time when the location information acquisition device 20 acquired the location information immediately preceding the time of maximum intensity. Furthermore, the immediate time refers to the time when the position information acquisition device 20 acquires the immediate position information immediately following the time of maximum intensity. Furthermore, since the number of data points referenced by the relay device 3 to the memory unit 21 is at most a few hundred, the data retrieval load is not high.

[0038] Here, a specific example of how server 5 calculates the position of wireless transmitter 2 will be explained using Figure 4. For example, consider the case where the location information transmitted by relay device 3 is 10:00:00:00 for A and 10:10:00:00 for B. Furthermore, we assume that the individual information of the supplementary data at 10:10:00:00, including the maximum intensity value, maximum intensity time, preceding time, preceding location information, succeeding time, and succeeding location information, is as shown in Table 2. [Table 2]

[0039] In Figure 4, first, points Aα and Bα are connected by a straight line, and the movement of the repeater 3 over 1 second is approximated as a straight line at a constant velocity. Next, a circular region corresponding to the maximum intensity value (-40dB) is set centered on position α, which corresponds to the time of maximum intensity of individual information α (10:03:35:50), and this circular region is defined as the area where the wireless transmitter 2 containing individual information α at the time of maximum intensity is located.

[0040] Similarly, first, we connect point Aβ and point Bβ with a straight line and approximate the movement of repeater 3 over 1 second with a constant velocity linear approximation. Next, a circular region corresponding to the maximum intensity value (-50dB) is set centered on position β, which corresponds to the time of maximum intensity of individual information β (10:08:40:80), and this circular region is defined as the area where the wireless transmitter 2 containing individual information β at the time of maximum intensity is located.

[0041] Then, the server 5 displays the location of the wireless transmitter 2 on the display unit 11, as shown in Figure 4, on map information (not shown). Furthermore, the display unit 11 can switch between wide-area and detailed display of the displayed object, and when wide-area display is selected, the A and B positions can be displayed. In the figure, the dotted line represents a straight line connecting A and B.

[0042] Furthermore, if Server 5 determines that the preceding time, preceding location information, subsequent time, subsequent location information, etc. of the accompanying data are clearly unreasonable, it will use the identification location information, reception time, etc. transmitted by Relay Unit 3 to determine the location of Transmitter 2.

[0043] [Effects of Example 2] The supplementary data also includes the location information acquired immediately before the time of maximum intensity, the location information acquired immediately after the time of maximum intensity, the time immediately before, and the time immediately after. This allows the location of the transmitter 2 to be more precisely determined than the location information history of the storage unit 21 of other location information acquisition devices 20.

[0044] [Differentiation] The present invention can be modified in various ways without departing from its essence. For example, in the embodiment, the carrier wave of the individual signals was set to 920 MHz, but there are no particular limitations as long as it utilizes a specific low-power band that complies with the Japanese Radio Law. Considering radio wave attenuation and the effective transmission range, the carrier frequency is preferably in the sub-GHz band of 300MHz to 1GHz.

[0045] In this embodiment, there was one repeater 3 and two wireless transmitters 2, but it is also possible to use multiple repeaters 3 and one wireless transmitter 2. This allows for a more accurate determination of the location of the wireless transmitter 2 by combining information from multiple relay devices 3. Furthermore, the location management system 1 may consist of multiple repeaters 3 and three or more wireless transmitters 2.

[0046] In this embodiment, the transmission interval of individual signals from the wireless transmitter 2 was set to 10 s and the transmission period to 10 ms, but the embodiment is not limited to this configuration. To prevent interference between each wireless transmitter 2 and ensure reliable reception by the repeater 3, it is preferable to set the transmission interval to 1 to 30 seconds and the transmission period to 0.5 to 100 ms.

[0047] In this embodiment, the relay device 3 acquired location information at 10-minute intervals and transmitted identified location information at 10-minute intervals, but the embodiment is not limited to this configuration. To ensure that signals from multiple wireless transmitters 2 are acquired without fail and to guarantee the accuracy of the calculated position of the wireless transmitters 2, it is preferable that the position information acquisition interval be 1 to 20 minutes.

[0048] In this embodiment, the wireless transmitter 2 was carried by a pedestrian p, but the invention is not limited to this configuration. The wireless transmitter 2 may be attached to luggage or other items. If the wireless transmitter 2 is carried by the pedestrian p, it can be charged as needed, but if it is attached to luggage or other items, this cannot be done, making it highly practical for long-term operation.

[0049] In the embodiment, the repeater 3 was a mobile unit, but the repeater 3 may also include a stationary unit. If the repeater 3 is a stationary unit, power can be supplied separately via a wired connection from another location, thus maintaining a more stable reception state. Furthermore, if the repeater 3 is a stationary unit, it does not move, which can further improve the accuracy of the calculated position of the wireless transmitter 2. [Explanation of symbols]

[0050] 1. Location management system 2. Wireless transmitter 3. Repeater 5. Server 7. Receiver

Claims

1. A wireless transmitter that transmits individual signals containing individual information at predetermined time intervals, A relay device that acquires location information at predetermined time intervals and transmits identified location information, which is the location information with identification information attached, at predetermined time intervals. The system includes a server that receives and stores the identification location information transmitted from the relay device, The relay unit includes a mobile body and has a receiving unit that receives the individual signal. When it receives the individual signal, it acquires the signal strength of the individual signal, stores the maximum intensity value which is the maximum value of the signal strength and the time at which that value occurs, and transmits supplementary data to the identification location information, which includes the individual information, the maximum intensity value, and the maximum intensity time. The server is a position management system that calculates the position of a wireless transmitter from the associated data.

2. The location management system according to claim 1, wherein the associated data further includes: immediate location information acquired by another location information acquisition device at the time immediately preceding the time of maximum intensity; immediate location information acquired by the location information acquisition device at the time immediately following the time of maximum intensity; the immediate time; and the immediate time.

3. The position management system according to claim 1 or 2, wherein the frequency of the individual signals is 300 MHz to 1 GHz.

4. The position management system according to claim 3, further comprising a display unit for displaying the position of the wireless transmitter.

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