JP7724482B2 - Positioning method, program, and positioning system - Google Patents

Description

This disclosure relates generally to positioning methods, programs, and positioning systems, and more particularly to positioning methods, programs, and positioning systems for determining the position of a beacon terminal.

The location detection system described in Patent Document 1 has a predetermined area in which the location of a mobile communication device (beacon terminal) can be detected. Therefore, the range (from the lower limit to the upper limit) of radio wave strength at the reception point of a reference signal wirelessly transmitted between the mobile communication device and a fixed communication device is theoretically determined. Therefore, the administrator of the location detection system pre-sets an effective range, ranging from the lower limit of the theoretical range of radio wave strength minus a margin value to the upper limit plus the margin value. The location of the mobile communication device is calculated by excluding fixed communication devices whose radio wave strength is abnormal due to the effects of multipath, etc.

International Publication No. 2020/021739

The present disclosure aims to provide a positioning method, program, and positioning system that can improve the positioning accuracy of beacon terminals.

A positioning method according to one aspect of the present disclosure is a positioning method for determining the position of a beacon terminal based on the RSSI of a beacon signal transmitted from the beacon terminal. The positioning method includes a step of acquiring the RSSI of the beacon signal from each of a plurality of scanners that receive the beacon signal. The positioning method further includes a determination step of determining an instantaneous RSSI value of a target scanner among the plurality of scanners at a predetermined time point as an abnormal value when a plurality of conditions, including a first condition, a second condition, and a third condition, are all satisfied. The positioning method further includes a step of determining the position of the beacon terminal based on two or more RSSIs excluding the RSSI value determined to be the abnormal value in the determination step. The first condition is a condition that a value obtained by subtracting a first average value of a target scanner among the plurality of scanners from the instantaneous RSSI value of the target scanner at the predetermined time point is greater than a threshold. The first average value is an average RSSI value for a first period prior to or including the predetermined time point. The second condition is that, for the scanner of interest, the first average value is smaller than a second average value, which is an average value of RSSIs for a second period prior to the first period. The third condition is that, for a scanner of the plurality of scanners having the largest first average value, the first average value is larger than the second average value.

A program according to one aspect of the present disclosure is a program for causing one or more processors to execute a positioning method according to any of the above aspects.

A positioning system according to one aspect of the present disclosure is a positioning system that determines the position of a beacon terminal based on the RSSI of a beacon signal transmitted from the beacon terminal. The positioning system includes an acquisition unit that acquires the RSSI of the beacon signal from each of a plurality of scanners that receive the beacon signal. The positioning system further includes a determination unit that determines an instantaneous RSSI value of a target scanner among the plurality of scanners at a predetermined time point as an abnormal value when a plurality of conditions, including a first condition, a second condition, and a third condition, are all satisfied. The positioning system further includes a positioning unit that determines the position of the beacon terminal based on two or more RSSIs excluding the RSSI value determined to be the abnormal value by the determination unit. The first condition is that a value obtained by subtracting a first average value of a target scanner among the plurality of scanners from the instantaneous RSSI value of the target scanner at the predetermined time point is greater than a threshold. The first average value is an average RSSI value for a first period that precedes or includes the predetermined time point. The second condition is that, for the scanner of interest, the first average value is smaller than a second average value, which is an average value of RSSIs for a second period prior to the first period. The third condition is that, for a scanner of the plurality of scanners having the largest first average value, the first average value is larger than the second average value.

FIG. 1 is a block diagram of a system for implementing a positioning method according to the first embodiment. FIG. 2 is a schematic plan view of a space to which the positioning method is applied. FIG. 3 is a graph showing the measurement results of RSSI in the above positioning method. FIG. 4 is a flowchart showing the positioning method. FIG. 5 is a graph showing the measurement results of RSSI in the positioning method according to the second embodiment. FIG. 6 is a flowchart showing the positioning method.

In the following embodiments, the positioning method, program, and positioning system of the present disclosure are described using drawings. However, the following embodiments are only a part of the various embodiments of the present disclosure. Various modifications can be made to the following embodiments depending on the design, etc., as long as the objective of the present disclosure can be achieved.

(Embodiment 1)
(overview)
As shown in Figures 1 and 2, a facility is assumed in which multiple scanners 4 are installed. The multiple scanners 4 are installed, for example, on the ceiling of the facility. In Figure 2, the position of each scanner 4 is indicated by a black circle. The facility may be, for example, an office building, a factory, a commercial complex, a library, an art gallery, a museum, an amusement facility, a theme park, a park, an airport, a train station, a baseball stadium, a hotel, a hospital, or a residence. Alternatively, the facility may be, for example, a mobile object such as a ship or a railroad vehicle.

Multiple users using the facility each carry a beacon terminal 5. The positioning system 1 is used together with at least one beacon terminal 5 and multiple scanners 4. The beacon terminal 5 is, for example, a communication terminal such as a smartphone. Furthermore, the beacon terminal 5 is not limited to a smartphone, but may be a tablet-type mobile terminal or a terminal dedicated to the positioning system 1, such as a tag. Furthermore, the beacon terminal 5 may be owned by the user or may be borrowed. Only one beacon terminal 5 is shown in Figure 1.

Each beacon terminal 5 is assigned identification information, and the positioning system 1 distinguishes between multiple beacon terminals 5 based on the identification information.

The beacon terminal 5 transmits a beacon signal. Each of the multiple scanners 4 receives the beacon signal and measures the received signal strength (RSSI: Received Signal Strength Indication). Basically, the greater the distance between the beacon terminal 5 and the scanner 4, the smaller the RSSI. The positioning system 1 determines the distance between each of the multiple scanners 4 and the beacon terminal 5 based on the RSSI of each of the multiple scanners 4, thereby being able to determine the position of the beacon terminal 5.

However, interference and reflection of radio waves as beacon signals can cause variations in RSSI. For example, even if a scanner 4 is far away from the beacon terminal 5, the RSSI may momentarily increase. Or, even if a scanner 4 is sufficiently close to the beacon terminal 5, the RSSI may momentarily decrease. Variations in RSSI can cause a decrease in the positioning accuracy of the beacon terminal 5. Therefore, the positioning system 1 of this embodiment determines that an RSSI value that momentarily increases or decreases is an abnormal value, and determines the position of the beacon terminal 5 based on two or more RSSIs excluding the RSSI determined to be an abnormal value. This can improve positioning accuracy.

The positioning system 1 of this embodiment is a positioning system that determines the position of a beacon terminal 5 based on the RSSI of a beacon signal transmitted from the beacon terminal 5. The positioning system 1 includes an acquisition unit 21 that acquires the RSSI of the beacon signal from each of a plurality of scanners 4 that receive the beacon signal. The positioning system 1 also includes a determination unit 22 that determines the instantaneous RSSI value of a target scanner 4 at a predetermined time point as an abnormal value if the difference between the instantaneous RSSI value of a target scanner 4 at a predetermined time point and the average RSSI value of a target scanner 4 over a predetermined period of time is outside a predetermined range. The positioning system 1 also includes a positioning unit 23 that determines the position of the beacon terminal 5 based on two or more RSSIs excluding the RSSI determined to be an abnormal value by the determination unit 22.

The positioning method of this embodiment is realized by a positioning system 1. The positioning method is a method for determining the position of a beacon terminal 5 based on the RSSI of a beacon signal transmitted from the beacon terminal 5. The positioning method includes a step of acquiring the RSSI of the beacon signal for each of a plurality of scanners 4 that receive the beacon signal. The positioning method further includes a determination step of determining the instantaneous RSSI value of a target scanner 4 at a predetermined time point as an abnormal value if the difference between the instantaneous RSSI value of a target scanner 4 at a predetermined time point and the average RSSI value of a target scanner 4 over a predetermined period of time is outside a predetermined range. The positioning method further includes a step of determining the position of the beacon terminal 5 based on two or more RSSIs excluding the RSSI determined to be an abnormal value in the determination step.

According to this embodiment, the positioning accuracy of the beacon terminal 5 can be improved compared to when the position of the beacon terminal 5 is determined based on multiple RSSIs, including an RSSI that is an abnormal value.

(detail)
(1) Overall Configuration Each of the positioning system 1, the scanner 4, and the beacon terminal 5 includes a computer system having one or more processors and memories. At least some of the functions of each of the positioning system 1, the scanner 4, and the beacon terminal 5 are realized by the processor of the computer system executing a program recorded in the memory of the computer system. The program may be recorded in the memory, or may be provided via a telecommunications line such as the Internet, or may be recorded on a non-transitory recording medium such as a memory card and provided.

As shown in FIG. 1, the positioning system 1 has a processing unit 2, a first communication unit 31, and a memory unit 32. The scanner 4 has a first communication unit 41, a second communication unit 42, a memory unit 43, and a processing unit 44. The beacon terminal 5 has a first communication unit 51, a second communication unit 52, a memory unit 53, and a processing unit 54.

(1.1) First Communication Unit The positioning system 1, the scanner 4, and the beacon terminal 5 can communicate with each other via the first communication units 31, 41, and 51. That is, the "first communication unit" in this disclosure can communicate with other "first communication units." In this disclosure, "capable of communication" means that signals can be exchanged directly or indirectly via a network or a repeater, etc., by an appropriate communication method such as wired communication or wireless communication. Note that since the beacon terminal 5 is a device carried by the user, the first communication unit 51 of the beacon terminal 5 uses wireless communication as a communication method.

The communication method of the "first communication unit" is, for example, a communication method conforming to the Ethernet (registered trademark) standard, or Wi-Fi (registered trademark), etc.

(1.2) Second Communication Unit The second communication unit 42 of the scanner 4 and the second communication unit 52 of the beacon terminal 5 are used to measure the position of the beacon terminal 5. The second communication units 42, 52 have a communication function for performing wireless communication using radio waves. The communication method of the second communication units 42, 52 is, for example, Bluetooth (registered trademark) Low Energy or Wi-Fi (registered trademark).

The second communication unit 52 of the beacon terminal 5 transmits a beacon signal, which is a wireless signal. The beacon signal is, for example, a wireless signal called an advertisement packet. The second communication unit 52 wirelessly transmits the beacon signal at a predetermined time interval and with a predetermined transmission power. The second communication unit 42 of the scanner 4 receives the beacon signal transmitted from the second communication unit 52. The beacon signal contains identification information of the beacon terminal 5. The identification information is, for example, a Bluetooth (registered trademark) Device Address. The scanner 4 receives the beacon signal transmitted from the beacon terminal 5 at the second communication unit 42.

(2) Beacon Terminal The storage unit 53 of the beacon terminal 5 stores information about the beacon terminal 5. The information about the beacon terminal includes, for example, identification information of the beacon terminal 5.

The processing unit 54 of the beacon terminal 5 performs overall control of the beacon terminal 5.

(3) Scanner The plurality of scanners 4 are arranged in a matrix (see FIG. 2). The plurality of scanners 4 are arranged at equal intervals.

The memory unit 43 of the scanner 4 stores information about the scanner 4. The information about the scanner 4 includes, for example, identification information of the scanner 4.

The processing unit 44 of the scanner 4 calculates the RSSI of the beacon signal received by the second communication unit 42 of the scanner 4. The processing unit 44 also performs overall control of the scanner 4.

(4) Positioning System The positioning system 1 is, for example, a server computer. The positioning system 1 may be installed inside a facility where multiple scanners 4 are installed, or may be installed outside the facility.

The memory unit 32 of the positioning system 1 stores the position information and identification information of the multiple scanners 4. The position information and identification information of the multiple scanners 4 are registered in the positioning system 1, for example, by a facility manager when the multiple scanners 4 are installed in a facility. Alternatively, the position information and identification information of the multiple scanners 4 are transmitted from the multiple scanners 4 to the positioning system 1, for example. The position information of the multiple scanners 4 includes information on the distances between the multiple scanners 4.

The processing unit 2 of the positioning system 1 includes a computer system having one or more processors and memory. The functions of the processing unit 2 are realized by the processor of the computer system executing a program recorded in the memory of the computer system. In other words, the positioning system 1 is equipped with one or more processors for executing the positioning method of this embodiment. Furthermore, the program of this embodiment is a program for causing one or more processors to execute the positioning method of this embodiment.

The processing unit 2 has an acquisition unit 21, a determination unit 22, and a positioning unit 23. The acquisition unit 21, determination unit 22, and positioning unit 23 merely indicate functions realized by the processing unit 2 and do not necessarily indicate actual configurations.

The acquisition unit 21 acquires the RSSI of the beacon signal from each of the multiple scanners 4. More specifically, the acquisition unit 21 acquires the RSSI via the first communication unit 31. The acquisition unit 21 also acquires the identification information of the beacon terminal 5 corresponding to the RSSI and the identification information of the scanner 4 corresponding to the RSSI, along with the RSSI. Note that when a scanner 4 receives a beacon signal transmitted from a beacon terminal 5 and the RSSI is measured, with regard to this RSSI, the "beacon terminal 5 corresponding to the RSSI" is the beacon terminal 5, and the "scanner 4 corresponding to the RSSI" is the scanner 4.

The judgment unit 22 determines whether the RSSI measured by each scanner 4 is an abnormal value.

The positioning unit 23 determines the position of the beacon terminal 5 based on multiple RSSIs measured by multiple scanners 4. Here, the positioning unit 23 excludes the RSSIs determined to be abnormal values by the determination unit 22 and determines the position of the beacon terminal 5 based on the other RSSIs.

(5) Positioning Method Hereinafter, an example of a positioning method for locating the position of the beacon terminal 5 based on a plurality of RSSIs will be described.

In Figure 2, the 25 scanners 4 installed in the room are distinguished by being labeled with the letters A through Y. Below, the scanner 4 labeled with the letter "A" will be referred to as the "A" scanner 4. The scanners 4 labeled with the letters "B" through "Y" will also be referred to with the letters "B" through "Y".

As shown by the arrows in Figure 2, assume that a user carrying a beacon terminal 5 moves from near the scanner 4 marked "C" to near the scanner 4 marked "R." Also, assume that the user moves in a straight line at a constant speed. Each scanner 4 measures the RSSI a predetermined number of samples (three times in this embodiment) at a given time point, and then measures the RSSI a predetermined number of samples each time a predetermined time elapses. Specifically, each scanner 4 measures the RSSI three times at times t0, t1, ..., t8. In Figure 2, the symbol tα is added to the position of the beacon terminal 5 (user) at time tα (α = 0, 1, ..., 8). The interval between one time point and the next is, for example, one second. Note that measuring a predetermined number of RSSI samples at a certain point in time does not necessarily mean simultaneously measuring a predetermined number of RSSI samples, but may also mean sequentially measuring a predetermined number of RSSI samples in a time period (e.g., 0.05 seconds) that is short compared to the interval between one point in time and the next point in time.

Figure 3 shows an example of the RSSI measurement results for scanner "C" 4. Each dot in Figure 3 represents an instantaneous RSSI value. Curve c1 is the theoretical RSSI value calculated from the distance d between scanner "C" 4 and beacon terminal 5. The relationship between the distance d and the theoretical RSSI value is expressed by [Equation 1].

Tpower is the RSSI measured by scanner "C"'s scanner 4 that receives a beacon signal when a beacon terminal 5 transmits a beacon signal at a location 1 m away from scanner "C". Tpower is pre-stored in the memory unit 32 of the positioning system 1.

The determination unit 22 of the processing unit 2 extracts the instantaneous RSSI value at a predetermined time point of a scanner 4 of interest among the multiple scanners 4. Here, the scanner 4 of interest is scanner 4 "C". The predetermined time point is time point t8. Time point t8 is the time point closest to the present. In other words, the predetermined time point is the time point at which the most recent RSSI was measured. In short, the determination unit 22 extracts the instantaneous RSSI values iv1, iv2, and iv3 (see Figure 3) of scanner 4 "C" at time point t8.

The determination unit 22 also calculates the average RSSI value Ave1 (see Figure 3) for a specified period of time for a specified target scanner among the multiple scanners 4. Here, the target scanner is scanner 4 "C." In other words, the target scanner is the "scanner 4 of interest." The specified period is the period from time t4 to time t7. In other words, the specified period is the period before the specified time t8. More specifically, the specified period is the period that includes the measurement time (time t7) immediately before the specified time t8.

As described above, the determination unit 22 calculates the average RSSI value Ave1 for a predetermined period of time for a predetermined target scanner among the multiple scanners 4. In other words, the determination unit 22 calculates the average RSSI value Ave1 of 12 RSSI values consisting of three RSSI values at time t4, three RSSI values at time t5, three RSSI values at time t6, and three RSSI values at time t7.

The determination unit 22 determines whether each of the extracted instantaneous values iv1, iv2, and iv3 is an abnormal value. More specifically, if the difference between the instantaneous value and the average value Ave1 is outside a predetermined range, the determination unit 22 determines the instantaneous value to be an abnormal value. For example, the determination unit 22 calculates the difference between the instantaneous value and the average value Ave1 by subtracting the average value Ave1 from the instantaneous value. In Figure 3, the difference Δr1 between the instantaneous value iv1 and the average value Ave1 is approximately 25 dBm. The predetermined range is a range that includes 0. The upper and lower limits of the predetermined range are pre-stored in the memory unit 32 of the positioning system 1 (see Figure 1). Here, the predetermined range is set to a range between -20 dBm and 20 dBm. The difference Δr1 between the instantaneous value iv1 and the average value Ave1 is outside the predetermined range, so the determination unit 22 determines that the instantaneous value iv1 is an abnormal value. On the other hand, the differences between the instantaneous values iv2 and iv3 and the average value Ave1 are within the predetermined range, so the determination unit 22 determines that the instantaneous values iv2 and iv3 are not abnormal values (are normal values).

The upper and lower limits of the specified range are determined in advance based on the estimated movement of the beacon terminal 5 from the interval between the specified period and the specified time point t8. For example, assume that the user carrying the beacon terminal 5 is expected to move a maximum of 8 m between the midpoint of the specified period and the specified time point t8. In this case, the upper limit of the specified range is determined to be the amount of change calculated using [Equation 1], i.e., the amount of change in RSSI when the distance between the scanner 4 and the beacon terminal 5 changes by 8 m, and the lower limit of the specified range is determined to be -1 times the upper limit.

The judgment unit 22 similarly selects scanners 4 other than scanner 4 "C" in turn as "scanners 4 of interest" and determines whether the instantaneous RSSI value at time t8 is an abnormal value.

The positioning unit 23 (see Figure 1) of the positioning system 1 determines the position of the beacon terminal 5 based on two or more RSSIs, excluding RSSIs determined to be abnormal values. More specifically, the positioning unit 23 determines the distance d between each of the multiple scanners 4 and the beacon terminal 5 using [Equation 2].

RSSI_ave in [Equation 2] is the average RSSI value excluding RSSI values determined to be abnormal. For example, RSSI_ave at time t8 for scanner 4 "C" is the average of instantaneous values iv2 and iv3 excluding abnormal values from instantaneous values iv1, iv2, and iv3.

Furthermore, the positioning unit 23 determines the position of the beacon terminal 5 by performing three-point positioning using, for example, the position information of the multiple scanners 4 and the distance d between each of the multiple scanners 4 and the beacon terminal 5.

As described above, the positioning system 1 considers an instantaneous RSSI value that deviates significantly from the average RSSI value Ave1 for a specified period of the target scanner to be an abnormal value and does not use it to position the beacon terminal 5. This reduces the possibility that, for example, the instantaneous RSSI value of a certain scanner 4 will momentarily increase, causing the distance between the scanner 4 and the beacon terminal 5 to be calculated as shorter than it actually is. It also reduces the possibility that, for example, the instantaneous RSSI value of a certain scanner 4 will momentarily decrease, causing the distance between the scanner 4 and the beacon terminal 5 to be calculated as longer than it actually is. Therefore, by using the positioning system 1 of this embodiment, positioning accuracy can be improved.

The above-described positioning method is shown as a flowchart in Figure 4. Note that the flowchart shown in Figure 4 is merely one example of a positioning method according to the present disclosure, and the order of processing may be changed as appropriate, and processing may be added or omitted as appropriate.

In step ST1, each scanner 4 measures its RSSI. The measured RSSI is sequentially acquired by the acquisition unit 21 of the positioning system 1. When the RSSI is measured at a certain point in time (for example, point in time t8), the determination unit 22 then selects a scanner 4 of interest in step ST2. For example, the determination unit 22 first selects scanner 4 "A". When returning to step ST2 from subsequent step ST5, the determination unit 22 selects another scanner 4. Steps ST2 to ST5 are repeated until all scanners 4 have been selected.

After step ST2, in step ST3, the judgment unit 22 calculates the RSSI of the scanner 4 of interest at a predetermined time t8, i.e., the latest RSSI, minus the average RSSI value Ave1 of the scanner 4 over a predetermined period. If this value is outside the predetermined range, the judgment unit 22 determines that the latest RSSI is an abnormal value (step ST4).

The determination unit 22 determines whether the instantaneous RSSI value is an abnormal value in steps ST2 to ST4 until all scanners 4 are sequentially designated as the target scanner 4, i.e., until the determination in step ST5 becomes "Yes." In other words, the determination unit 22 determines whether the instantaneous RSSI value at the predetermined time point t8 of all scanners 4 is an abnormal value. Thereafter, the positioning unit 23 determines the position of the beacon terminal 5 using two or more RSSIs excluding the RSSI determined to be an abnormal value (step ST6).

At the next point in time (for example, one second after point t8), each scanner 4 measures the RSSI (step ST1). Similarly, the determination unit 22 determines whether the new RSSI is an abnormal value.

(Modification of the first embodiment)
The following are examples of modifications of the first embodiment. The following modifications may be implemented in appropriate combination.

In embodiment 1, the determination unit 22 determines that the instantaneous value iv1 is an abnormal value if the difference Δr1 between the instantaneous value iv1 and the average value Ave1 is outside a predetermined range. Here, the predetermined range may have only one of an upper limit and a lower limit. In other words, the determination unit 22 may determine that the instantaneous value iv1 is an abnormal value only if the difference Δr1 is greater than the upper limit, or may determine that the instantaneous value iv1 is an abnormal value only if the difference Δr1 is smaller than the lower limit.

In embodiment 1, the target scanner is the scanner 4 of interest. Alternatively, the target scanner may be the scanner 4 with the highest average RSSI value for a predetermined period among multiple scanners 4. The determination unit 22 identifies the scanner 4 with the highest average value by calculating the average RSSI value for the predetermined period for each of the multiple scanners 4, and selects that scanner 4 as the target scanner. For example, if the predetermined period is the period from time t4 to time t7, the scanner 4 with the highest average RSSI value for the predetermined period among the multiple (25) scanners 4 shown in FIG. 2 is likely to be the scanner 4 located near the beacon terminal 5 during the predetermined period (e.g., scanner 4 "M" or "R").

In embodiment 1, the predetermined period is a time point prior to the predetermined time point t8. Alternatively, the predetermined period may include the predetermined time point t8.

Alternatively, the specified period may be a time point later than the specified time point t8. In this case, the determination unit 22 determines whether the instantaneous value of the RSSI at the specified time point t8 in the past is an abnormal value.

In embodiment 1, each of the multiple scanners 4 measures the RSSI three times at each of the times t0 to t8. However, the number of measurements at each of the times t0 to t8 may be one, two, four or more.

The length of the specified period may be different from that in embodiment 1.

At least one of the multiple scanners 4 and one or more beacon terminals 5 may be included in the configuration of the positioning system 1.

In this disclosure, when comparing two values, "greater than or equal to" includes both cases where the two values are equal and cases where one of the two values exceeds the other. However, this is not limited to this, and "greater than or equal to" here may also be synonymous with "greater than," which includes only cases where one of the two values exceeds the other. In other words, whether or not the case where the two values are equal can be arbitrarily changed depending on the setting of the reference value, etc., so there is no technical difference between "greater than or equal to" and "greater than." Similarly, "less than or equal to" may also be synonymous with "less than."

The positioning system 1 of the present disclosure includes a computer system. The computer system is primarily composed of a processor and memory as hardware. At least a portion of the functions of the positioning system 1 of the present disclosure are realized by the processor executing a program stored in the computer system's memory. The program may be pre-stored in the computer system's memory, provided via a telecommunications line, or provided on a non-transitory recording medium readable by the computer system, such as a memory card, optical disk, or hard disk drive. The processor of the computer system is composed of one or more electronic circuits, including a semiconductor integrated circuit (IC) or a large-scale integrated circuit (LSI). The integrated circuits, such as ICs and LSIs, are referred to by different names depending on the degree of integration, and include integrated circuits called system LSIs, very large-scale integrations (VLSIs), or ultra-large-scale integrations (ULSIs). Furthermore, field-programmable gate arrays (FPGAs), which are programmed after the LSI is manufactured, or logic devices that allow the reconfiguration of internal connections or internal circuit partitions of the LSI, can also be used as processors. The electronic circuits may be integrated into one chip or distributed across multiple chips. The chips may be integrated into one device or distributed across multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller is also composed of one or more electronic circuits including a semiconductor integrated circuit or a large-scale integrated circuit.

Furthermore, it is not essential for the positioning system 1 that multiple functions in the positioning system 1 are consolidated into a single device; the components of the positioning system 1 may be distributed across multiple devices. Furthermore, at least some of the functions of the positioning system 1, for example, at least some of the functions of the determination unit 22, may be realized by the cloud (cloud computing) or the like.

(Embodiment 2)
Hereinafter, a description will be given of the second embodiment. The same components as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

In embodiment 2, the configurations of the positioning system 1, beacon terminal 5, and scanner 4 are the same as those in embodiment 1. The processing in the determination unit 22 of the positioning system 1 differs between embodiment 1 and embodiment 2.

In embodiment 1, the determination unit 22 determines that the instantaneous RSSI value of a focused scanner 4 among the multiple scanners 4 at a predetermined time point is an abnormal value when a predetermined condition is met. In contrast, in embodiment 2, the determination unit 22 determines that the instantaneous RSSI value of a focused scanner 4 among the multiple scanners 4 at a predetermined time point is an abnormal value when all of the multiple conditions are met. The predetermined condition is that the difference between the instantaneous RSSI value of a focused scanner 4 among the multiple scanners 4 at a predetermined time point and the average RSSI value of a targeted scanner among the multiple scanners 4 for a predetermined period of time is outside a predetermined range. As described below, the multiple conditions include a first condition, a second condition, and a third condition, and the first condition is an example of the predetermined condition. In short, the judgment unit 22 in embodiments 1 and 2 judges the instantaneous RSSI value of a focused scanner 4 among multiple scanners 4 at a specified point in time to be an abnormal value when one or more conditions including the above-mentioned specified condition are met, and in embodiment 2, the one or more conditions are multiple conditions.

The positioning system 1 of this embodiment is a positioning system that determines the position of a beacon terminal 5 based on the RSSI of a beacon signal transmitted from the beacon terminal 5. The positioning system 1 includes an acquisition unit 21 that acquires the RSSI of the beacon signal from each of multiple scanners 4 that receive the beacon signal. Furthermore, the positioning system 1 includes a determination unit 22 that determines the instantaneous RSSI value of a target scanner 4 of the multiple scanners 4 at a predetermined time point as an abnormal value when all of a first condition, a second condition, and a third condition are met. Furthermore, the positioning system 1 includes a positioning unit 23 that determines the position of the beacon terminal 5 based on two or more RSSIs excluding the RSSI determined to be an abnormal value by the determination unit 22. The first condition is that the value obtained by subtracting a first average value of a target scanner of the multiple scanners 4 from the instantaneous RSSI value of the target scanner 4 at a predetermined time point is greater than a threshold value. The first average value is the average RSSI value for a first period. The first period is a period before a predetermined point in time or a period including the predetermined point in time. The second condition is that, for a scanner 4 of interest, the first average value is smaller than a second average value, which is the average value of RSSI for a second period before the first period. The third condition is that, for a scanner 4 with the largest first average value among the multiple scanners 4, the first average value is larger than the second average value.

The positioning method of this embodiment determines the position of a beacon terminal 5 based on the RSSI of a beacon signal transmitted from the beacon terminal 5. The positioning method includes a step of acquiring the RSSI of the beacon signal from each of multiple scanners 4 that receive the beacon signal. The positioning method further includes a determination step of determining, if all of multiple conditions, including a first condition, a second condition, and a third condition, that the instantaneous RSSI value of a target scanner 4 of the multiple scanners 4 at a predetermined time point is an abnormal value. The positioning method further includes a step of determining the position of the beacon terminal 5 based on two or more RSSIs excluding the RSSI value determined to be an abnormal value in the determination step. The first condition is that the value obtained by subtracting a first average value of a target scanner of the multiple scanners 4 from the instantaneous RSSI value of the target scanner 4 at a predetermined time point is greater than a threshold value. The first average value is the average RSSI value for a first period. The first period is a period prior to or including the predetermined time point. The second condition is that the first average value for a scanner 4 of interest is smaller than the second average value, which is the average value of RSSI for a second period preceding the first period. The third condition is that the first average value for a scanner 4 having the largest first average value among the multiple scanners 4 is larger than the second average value.

The positioning method of this embodiment is described in more detail below.

First, please refer to Figure 2. As in embodiment 1, assume that a user carrying a beacon terminal 5 moves from the vicinity of the scanner 4 "C" to the vicinity of the scanner 4 "R". Figure 3 shows an example of the RSSI measurement results for the scanner 4 "C". Figure 5 shows an example of the RSSI measurement results for the scanner 4 "R". Curve c2 in Figure 5 is the theoretical RSSI value calculated from the distance d between the scanner 4 "R" and the beacon terminal 5.

The determination unit 22 extracts the instantaneous RSSI value at a predetermined time point of a scanner 4 of interest among multiple scanners 4. Here, the scanner 4 of interest is scanner 4 "C." The predetermined time point is time point t8. In short, the determination unit 22 extracts the instantaneous RSSI values iv1, iv2, and iv3 (see Figure 3) of scanner 4 "C" at time point t8.

The determination unit 22 also calculates a first average value Ave1 (see Figure 3), which is the average value of the RSSI for a specified target scanner among the multiple scanners 4, during the first period. The first average value Ave1 is the same as the "average value Ave1" in embodiment 1. Here, the target scanner is scanner 4 "C." In other words, the target scanner is the "scanner 4 of interest." The first period is the period from time t4 to time t7. In other words, the first period is the period that includes the measurement time (time t7) immediately before the specified time t8.

Furthermore, the determination unit 22 calculates a second average value Ave2 (see Figure 3), which is the average value of the RSSI for the second period of the focused scanner 4 (scanner 4 "C"). The second period is a period that precedes the first period. The second period being a period that precedes the first period means that the start point of the second period (time t0) is a time that precedes the start point of the first period (time t4) and the end point of the second period (time t3) is a time that precedes the end point of the first period (time t7). In this embodiment, the second period is the period from time t0 to time t3. In other words, in this embodiment, the end point of the second period is a time that precedes the start point of the first period. Note that the end point of the second period may also be a time that follows the start point of the first period.

Furthermore, the determination unit 22 calculates the individual first average value Ave1 for each of the multiple scanners 4. Then, among the multiple scanners 4, the scanner 4 with the largest first average value Ave1 is identified, and the second average value Ave2 (see Figure 5) for this scanner 4 is calculated. Here, it is assumed that the scanner 4 with the largest first average value Ave1 among the multiple scanners 4 is scanner 4 "R."

The determination unit 22 determines whether each of the instantaneous values iv1, iv2, and iv3 at a predetermined time point t8 of the scanner 4 of interest is an abnormal value. More specifically, the determination unit 22 determines the corresponding instantaneous value to be an abnormal value if all of the multiple conditions, including the first, second, and third conditions described above, are met. The determination unit 22 determines the corresponding instantaneous value to be not an abnormal value (a normal value) if at least one of the multiple conditions is not met. In this embodiment, the multiple conditions consist only of the first, second, and third conditions.

First, let us explain the first condition. The first condition is that the value obtained by subtracting the first average value Ave1 of the target scanner (scanner 4 designated by "C") from the instantaneous value of the RSSI of the scanner 4 of interest (scanner 4 designated by "C") at a predetermined time t8 is greater than a threshold value. The threshold value is, for example, greater than 0. The first condition is similar to the abnormal value determination condition (the above-mentioned predetermined condition) in the first embodiment when the predetermined range has only the upper limit of an upper limit and a lower limit. Here, the threshold value is set to 20 dBm. In Figure 3, of the instantaneous values iv1, iv2, and iv3, only instantaneous value iv1 satisfies the condition that the value obtained by subtracting the first average value Ave1 from the instantaneous value (difference Δr1) is greater than a threshold value.

Next, we will explain the second condition. The second condition is a condition in which the first average value Ave1 is smaller than the second average value Ave2 for the scanner 4 of interest (scanner 4 "C"). In other words, the second condition is basically met when the beacon terminal 5 moves away from the scanner 4 of interest between the second period and the first period. In Figure 3, the second condition is met for the scanner 4 of interest (scanner 4 "C").

Next, the third condition will be explained. The third condition is that, for the scanner 4 (scanner 4 marked "R") with the largest first average value Ave1 among multiple scanners 4, the first average value Ave1 is greater than the second average value Ave2. In other words, the third condition is basically met when the beacon terminal 5 approaches the scanner 4 with the largest first average value Ave1 between the second period and the first period. In Figure 5, the third condition is met for the scanner 4 with the largest first average value Ave1 (scanner 4 marked "R").

As explained above, in the examples shown in Figures 3 and 5, the second and third conditions are met, and furthermore, the first condition is met for instantaneous value iv1. Therefore, the judgment unit 22 judges that the instantaneous value iv1 of the RSSI of the focused scanner 4 (scanner 4 "C") at the specified time point t8 is an abnormal value. Since instantaneous values iv2 and iv3 do not satisfy the first condition, they are judged to be non-abnormal values (normal values).

The determination of abnormal values in this embodiment will now be explained qualitatively. The second and third conditions determine that the beacon terminal 5 moved away from the scanner 4 of "C" and approached the scanner 4 of "R" between the second period and the first period. Despite this, the first condition determines that the instantaneous value iv1 at the scanner 4 of "C" became a large value. In such a case, the determination unit 22 determines that the instantaneous value iv1 is an abnormal value.

The judgment unit 22 similarly selects scanners 4 other than scanner 4 "C" in turn as "scanners 4 of interest" and determines whether the instantaneous RSSI value at time t8 is an abnormal value.

The positioning unit 23 (see Figure 1) of the positioning system 1 determines the position of the beacon terminal 5 based on two or more RSSIs, excluding RSSIs determined to be abnormal values. That is, as in embodiment 1, the positioning unit 23 determines the distance d between each of the multiple scanners 4 and the beacon terminal 5 using [Equation 2]. Furthermore, the positioning unit 23 determines the position of the beacon terminal 5 by performing three-point positioning using, for example, the position information of the multiple scanners 4 and the distance d between each of the multiple scanners 4 and the beacon terminal 5.

The positioning method of this embodiment described above can improve the positioning accuracy of the beacon terminal 5 compared to determining the position of the beacon terminal 5 based on multiple RSSIs, including an RSSI that is an abnormal value. Furthermore, the second and third conditions make it possible to determine whether the beacon terminal 5 has moved. In other words, only when the beacon terminal 5 has moved can it be determined that an abnormal value has occurred due to movement. This reduces the amount of processing in the determination unit 22 of the positioning system 1.

The above-described positioning method is shown as a flowchart in Figure 6. Note that the flowchart shown in Figure 6 is merely one example of a positioning method according to the present disclosure, and the order of processing may be changed as appropriate, and processing may be added or omitted as appropriate.

In step ST21, each scanner 4 measures its RSSI. The measured RSSI is sequentially acquired by the acquisition unit 21 of the positioning system 1. When the RSSI is measured at a certain point in time (for example, point in time t8), the determination unit 22 then selects a scanner 4 of interest in step ST22. For example, the determination unit 22 first selects scanner 4 "A". When returning to step ST22 from subsequent step ST27, the determination unit 22 selects another scanner 4. Steps ST22 to ST27 are repeated until all scanners 4 have been selected.

After step ST22, in step ST23, the judgment unit 22 calculates the RSSI of the scanner 4 of interest at a predetermined time t8, i.e., the latest RSSI, minus the first average value Ave1 of the scanner 4. If this value is greater than the threshold, the process proceeds to step ST24. On the other hand, if this value is equal to or less than the threshold, the judgment unit 22 determines that the latest RSSI is a normal value.

In step ST24, the judgment unit 22 determines whether the first average value Ave1 of the focused scanner 4 is smaller than the second average value Ave2. If the first average value Ave1 is smaller than the second average value Ave2, the process proceeds to step ST25. On the other hand, if the first average value Ave1 is equal to or greater than the second average value Ave2, the judgment unit 22 determines that the latest RSSI is a normal value.

In step ST25, the judgment unit 22 determines whether the first average value Ave1 of the scanner 4 with the largest first average value Ave1 is greater than the second average value Ave2. If the first average value Ave1 is greater than the second average value Ave2, the judgment unit 22 determines that the latest RSSI is an abnormal value (step ST26). On the other hand, if the first average value Ave1 is equal to or less than the second average value Ave2, the judgment unit 22 determines that the latest RSSI is a normal value.

The determination unit 22 determines whether the instantaneous RSSI value is an abnormal value in steps ST22 to ST26 until all scanners 4 have been sequentially selected as the target scanner 4, that is, until the determination in step ST27 becomes "Yes." The positioning unit 23 then determines the position of the beacon terminal 5 using two or more RSSIs excluding the RSSI determined to be an abnormal value (step ST28).

At the next point in time (for example, one second after point t8), each scanner 4 measures the RSSI (step ST21). Similarly, the determination unit 22 determines whether the new RSSI is an abnormal value.

In the second embodiment, as in the first embodiment, the positioning system 1 includes one or more processors (processing unit 2) for executing the positioning method. Furthermore, a program according to one aspect is a program for causing one or more processors to execute the positioning method of the second embodiment.

(Modification 1 of Embodiment 2)
The following describes Modification 1 of Embodiment 2. The same components as those in Embodiment 2 are denoted by the same reference numerals and the description thereof will be omitted.

In Variant 1, the multiple conditions for determining abnormal values include a fourth condition in addition to the first, second, and third conditions. The fourth condition is that the value obtained by subtracting the first average value Ave1 of the scanner 4 with the largest first average value Ave1 among the multiple scanners 4 from the second average value Ave2 of the scanner 4 of interest is greater than a predetermined value. The predetermined value is greater than 0.

Let us assume that the scanner 4 of interest is scanner 4 "C." Among the multiple scanners 4, the scanner 4 with the largest first average value Ave1 is scanner 4 "R." Referring to Figures 3 and 5, the value obtained by subtracting the first average value Ave1 of scanner 4 "R" from the second average value Ave2 of scanner 4 "C" is approximately 5 dBm.

Since the first average value Ave1 of scanner 4 for "R" is the largest first average value, when the fourth condition is met, the first average value Ave1 of scanner 4 for "C" is smaller than the first average value Ave1 of scanner 4 for "R". Thus, when the first average value Ave1 of scanner 4 for "C" in the first period is determined to be sufficiently smaller than the second average value Ave2 in the second period, and the instantaneous value of scanner 4 for "C" is determined to be larger than the first condition, the determination unit 22 determines that the instantaneous value is an abnormal value.

(Modification 2 of Embodiment 2)
The following describes Modification 2 of Embodiment 2. The same components as those in Embodiment 2 are denoted by the same reference numerals and the description thereof will be omitted.

In this second variation, the multiple conditions for determining an abnormal value include a fifth condition that, for a scanner 4 of interest (e.g., scanner 4 "C"), the value obtained by subtracting the first average value Ave1 from the second average value Ave2 is greater than a comparison value. The comparison value is greater than 0.

In addition, in this second variation, the multiple conditions for determining an abnormal value include a sixth condition that, for the scanner 4 with the largest first average value Ave1 among the multiple scanners 4 (e.g., scanner 4 "R"), the value obtained by subtracting the second average value Ave2 from the first average value Ave1 is greater than a reference value. The reference value is greater than 0.

For the scanner 4 of interest, the value obtained by subtracting the first average value Ave1 from the second average value Ave2 changes depending on the amount of movement of the beacon terminal 5 from the second period to the first period. Similarly, for the scanner 4 with the largest first average value Ave1, the value obtained by subtracting the second average value Ave2 from the first average value Ave1 changes depending on the amount of movement of the beacon terminal 5 from the second period to the first period. In other words, in this variant example 2, an abnormal value is determined only if the amount of movement of the beacon terminal 5 is equal to or greater than a certain amount.

In addition, the multiple conditions for determining abnormal values do not have to include one of the fifth and sixth conditions.

(Modification 3 of Embodiment 2)
The following describes Modification 3 of Embodiment 2. The same components as those in Embodiment 2 are denoted by the same reference numerals and the description thereof will be omitted.

In this variant example 3, the target scanner is the scanner 4 with the largest first average value Ave1 among multiple scanners 4. The first condition is met when the difference between the first average value Ave1 of such a scanner 4 and the instantaneous value of the scanner 4 of interest is greater than a threshold value.

The positioning method of Variation 3 may further include a process of determining a threshold value based on the distance between the scanner 4 with the largest first average value Ave1 among the multiple scanners 4 and the scanner 4 with the largest second average value Ave2 among the multiple scanners 4. The determination unit 22 calculates the distance based on the coordinates of each of the two scanners 4.

The above distance corresponds to the amount of movement of the beacon terminal 5 from the second period to the first period. If the effects of radio wave interference and reflection are not taken into account, the greater the above distance, the smaller the instantaneous value of the scanner 4 in question. Therefore, for example, the greater the above distance, the smaller the threshold value may be.

(Other Modifications of the Second Embodiment)
Other variations of the second embodiment are listed below. The following variations and the above-described variations 1, 2, and 3 may be implemented in appropriate combinations. The variations of the first embodiment may also be applied to the second embodiment as appropriate. The variations of the first embodiment may also be implemented in appropriate combinations with the variations of the second embodiment.

The scanner 4 of interest may be the scanner 4 with the largest second average value Ave2 among multiple scanners 4. In other words, the presence or absence of an abnormality in the instantaneous value of such a scanner 4 may be determined.

In embodiment 2, the first period is a time point prior to the predetermined time point t8. Alternatively, the first period may include the predetermined time point t8.

The lengths of the first period and the second period may each be different from those in embodiment 2. Furthermore, the lengths of the first period and the second period may be different from each other.

The multiple conditions for determining an abnormal value may further include a seventh condition that the distance between the scanner 4 with the largest first average value Ave1 among the multiple scanners 4 and the scanner 4 with the largest second average value Ave2 among the multiple scanners 4 is greater than a predetermined value. The distance is calculated based on the coordinates of each of the two scanners 4.

(summary)
The above-described embodiments and the like disclose the following aspects.

A positioning method according to a first aspect is a positioning method for determining the position of a beacon terminal (5) based on the RSSI of a beacon signal transmitted from the beacon terminal (5). The positioning method includes a step of acquiring the RSSI of the beacon signal for each of a plurality of scanners (4) that receive the beacon signal. The positioning method further includes a determination step of determining the instantaneous RSSI value of the target scanner (4) at the predetermined time point as an abnormal value if the difference between the instantaneous RSSI value of a target scanner (4) at the predetermined time point and the average RSSI value of a target scanner (4) over a predetermined period of time is outside a predetermined range. The positioning method further includes a step of determining the position of the beacon terminal (5) based on two or more RSSIs excluding the RSSI determined to be an abnormal value in the determination step.

According to the above configuration, the positioning accuracy of the beacon terminal (5) can be improved compared to when the position of the beacon terminal (5) is determined based on multiple RSSIs, including an RSSI that is an abnormal value.

Also, in the positioning method of the second aspect, in the first aspect, the specified period is a period prior to a specified point in time.

The above configuration makes it possible to perform positioning while removing abnormal values in real time.

Furthermore, in the positioning method of the third aspect, in the first or second aspect, the target scanner is the scanner of interest (4).

With the above configuration, abnormal values can be detected from changes in the RSSI of the scanner (4) of interest.

Furthermore, in the positioning method of the fourth aspect, in the first or second aspect, the target scanner is the scanner (4) among the multiple scanners (4) that has the largest average RSSI value (Ave1) for a specified period.

With the above configuration, abnormal values can be detected by comparing the RSSI of the scanner of interest (4) with the RSSI of the target scanner.

A positioning method according to a fifth aspect is a positioning method for determining the position of a beacon terminal (5) based on the RSSI of a beacon signal transmitted from the beacon terminal (5). The positioning method includes a step of acquiring the RSSI of the beacon signal from each of a plurality of scanners (4) that receive the beacon signal. The positioning method further includes a determination step of determining, when a plurality of conditions, including a first condition, a second condition, and a third condition, are all satisfied, that the instantaneous RSSI value of a target scanner (4) among the plurality of scanners (4) at a predetermined time point is an abnormal value. The positioning method further includes a step of determining the position of the beacon terminal (5) based on two or more RSSIs excluding the RSSI value determined to be an abnormal value in the determination step. The first condition is that the value obtained by subtracting the first average value (Ave1) of a target scanner among the plurality of scanners (4) from the instantaneous RSSI value of the target scanner (4) at a predetermined time point is greater than a threshold value. The first average value (Ave1) is the average value of RSSI for a first period before or including a predetermined time point. The second condition is that, for the scanner (4) of interest, the first average value (Ave1) is smaller than the second average value (Ave2), which is the average value of RSSI for a second period before the first period. The third condition is that, for the scanner (4) with the largest first average value (Ave1) among the multiple scanners (4), the first average value (Ave1) is greater than the second average value (Ave2).

The above configuration improves the positioning accuracy of the beacon terminal (5) compared to determining the position of the beacon terminal (5) based on multiple RSSIs, including an RSSI that is an abnormal value. Furthermore, the second and third conditions make it possible to determine whether the beacon terminal (5) has moved. In other words, only when the beacon terminal (5) has moved can it be determined that an abnormal value has occurred due to movement. Therefore, the amount of processing required to implement the positioning method can be reduced.

Furthermore, in the positioning method of the sixth aspect, in the fifth aspect, the multiple conditions further include a condition that the value obtained by subtracting the first average value (Ave1) of the scanner (4) having the largest first average value (Ave1) among the multiple scanners (4) from the second average value (Ave2) of the scanner (4) of interest is greater than a predetermined value greater than 0.

The above configuration reduces the possibility of mistakenly determining that a normal RSSI value is an abnormal value.

Furthermore, in the positioning method of the seventh aspect, in the fifth or sixth aspect, the multiple conditions include a condition that, for the scanner (4) of interest, the value obtained by subtracting the first average value (Ave1) from the second average value (Ave2) is greater than a comparison value greater than 0.

With the above configuration, abnormal values can be detected from the RSSI that changes due to the movement of the beacon terminal (5).

Furthermore, in the positioning method according to the eighth aspect, in any one of the fifth to seventh aspects, the multiple conditions include a condition that, for the scanner (4) having the largest first average value (Ave1) among the multiple scanners (4), the value obtained by subtracting the second average value (Ave2) from the first average value (Ave1) is greater than a reference value greater than 0.

With the above configuration, abnormal values can be detected from the RSSI that changes due to the movement of the beacon terminal (5).

Furthermore, in the positioning method according to the ninth aspect, in any one of the fifth to eighth aspects, the multiple conditions further include a condition that the distance between the scanner (4) having the largest first average value (Ave1) among the multiple scanners (4) and the scanner (4) having the largest second average value (Ave2) among the multiple scanners (4) is greater than a predetermined value.

With the above configuration, abnormal values can be detected from the RSSI that changes due to the movement of the beacon terminal (5).

Furthermore, in the positioning method of the tenth aspect, in any one of the fifth to ninth aspects, the scanner (4) of interest is the scanner (4) having the largest second average value (Ave2) among the multiple scanners (4).

With the above configuration, it is possible to narrow down the scanners (4) that are to be used to determine whether or not there are abnormal values.

Furthermore, in the positioning method of the 11th aspect, in any one of the 5th to 10th aspects, the target scanner is the scanner of interest (4).

With the above configuration, abnormal values can be detected from changes in the RSSI of the scanner (4) of interest.

Furthermore, in the positioning method of the 12th aspect, in any one of the 5th to 10th aspects, the target scanner is the scanner (4) having the largest first average value (Ave1) among the multiple scanners (4).

With the above configuration, abnormal values can be detected by comparing the RSSI of the scanner of interest (4) with the RSSI of the target scanner.

Configurations other than the first or fifth aspect are not essential to the positioning method of the present disclosure and may be omitted as appropriate.

Furthermore, the program relating to the thirteenth aspect is a program for causing one or more processors to execute the positioning method relating to any one of the first to twelfth aspects.

The above configuration can improve the positioning accuracy of the beacon terminal (5).

A positioning system (1) according to a fourteenth aspect of the present invention is a positioning system that determines the position of a beacon terminal (5) based on the RSSI of a beacon signal transmitted from the beacon terminal (5). The positioning system (1) includes an acquisition unit (21) that acquires the RSSI of the beacon signal from each of a plurality of scanners (4) that receive the beacon signal. The positioning system (1) also includes a determination unit (22) that determines the instantaneous RSSI value of a target scanner (4) at a predetermined time point as an abnormal value if the difference between the instantaneous RSSI value of a target scanner (4) at a predetermined time point and the average RSSI value of a target scanner (4) over a predetermined period of time is outside a predetermined range. The positioning system (1) also includes a positioning unit (23) that determines the position of the beacon terminal (5) based on two or more RSSI values excluding the RSSI value determined to be an abnormal value by the determination unit (22).

The above configuration can improve the positioning accuracy of the beacon terminal (5).

A positioning system (1) according to a fifteenth aspect is a positioning system that determines the position of a beacon terminal (5) based on the RSSI of a beacon signal transmitted from the beacon terminal (5). The positioning system (1) includes an acquisition unit (21) that acquires the RSSI of the beacon signal from each of a plurality of scanners (4) that receive the beacon signal. Furthermore, the positioning system (1) includes a determination unit (22) that determines, when a plurality of conditions, including a first condition, a second condition, and a third condition, are all satisfied, an instantaneous RSSI value at a predetermined time point of a focused scanner (4) among the plurality of scanners (4), to be an abnormal value. Furthermore, the positioning system (1) includes a positioning unit (23) that determines the position of the beacon terminal (5) based on two or more RSSIs excluding the RSSI determined to be an abnormal value by the determination unit (22). The first condition is that the value obtained by subtracting a first average value (Ave1) of a predetermined target scanner among the multiple scanners (4) from the instantaneous RSSI value of the target scanner (4) at a predetermined time point is greater than a threshold value. The first average value (Ave1) is the average RSSI value for a first period before or including the predetermined time point. The second condition is that, for the target scanner (4), the first average value (Ave1) is smaller than a second average value (Ave2), which is the average RSSI value for a second period before the first period. The third condition is that, for the scanner (4) with the largest first average value (Ave1) among the multiple scanners (4), the first average value (Ave1) is greater than the second average value (Ave2).

The above configuration can improve the positioning accuracy of the beacon terminal (5).

Not limited to the above aspects, various configurations (including modified examples) of the positioning system (1) according to each embodiment can be embodied as a positioning method, a (computer) program, or a non-transitory recording medium on which a program is recorded.

1 Positioning system 4 Scanner 5 Beacon terminal 21 Acquisition unit 22 Determination unit 23 Positioning unit Ave1 Average value, first average value Ave2 Second average value

Claims (10)

A positioning method for determining a position of a beacon terminal based on a Received Signal Strength Indication of a beacon signal transmitted from the beacon terminal,
acquiring a Received Signal Strength Indication of the beacon signal at each of a plurality of scanners receiving the beacon signal;
a determining step of determining that an instantaneous value of a Received Signal Strength Indication at a predetermined time point of a scanner of interest among the plurality of scanners is an abnormal value when all of a plurality of conditions including a first condition, a second condition, and a third condition are satisfied;
and determining the location of the beacon terminal based on two or more Received Signal Strength Indications excluding the Received Signal Strength Indication determined to be the abnormal value in the determination step,
the first condition is a condition that a value obtained by subtracting a first average value, which is an average value of Received Signal Strength Indication of a predetermined target scanner among the multiple scanners during a first period before or including the predetermined time point, from the instantaneous value of Received Signal Strength Indication of the scanner of interest at the predetermined time point is greater than a threshold value;
the second condition is a condition that, for the scanner of interest, the first average value is smaller than a second average value that is an average value of Received Signal Strength Indications for a second period prior to the first period;
the third condition is that, for a scanner having the largest first average value among the plurality of scanners, the first average value is larger than the second average value;
Positioning method. the plurality of conditions further include a condition that a value obtained by subtracting the first average value of a scanner having the largest first average value among the plurality of scanners from the second average value of the scanner of interest is greater than a predetermined value greater than 0;
The positioning method according to claim 1 . the plurality of conditions include a condition that, for the scanner of interest, a value obtained by subtracting the first average value from the second average value is greater than a comparison value greater than 0;
The positioning method according to claim 1 or 2. the plurality of conditions include a condition that, for a scanner among the plurality of scanners having the largest first average value, a value obtained by subtracting the second average value from the first average value is greater than a reference value greater than 0;
The positioning method according to any one of claims 1 to 3. the plurality of conditions further includes a condition that a distance between a scanner having the largest first average value among the plurality of scanners and a scanner having the largest second average value among the plurality of scanners is greater than a predetermined value;
The positioning method according to any one of claims 1 to 4. the scanner of interest is the scanner having the largest second average value among the plurality of scanners;
The positioning method according to any one of claims 1 to 5. the target scanner is the scanner of interest;
The positioning method according to any one of claims 1 to 6. the target scanner is the scanner among the plurality of scanners that has the largest first average value;
The positioning method according to any one of claims 1 to 6. A method for causing one or more processors to execute the positioning method according to any one of claims 1 to 8,
Program. A positioning system for determining a position of a beacon terminal based on a received signal strength indication of a beacon signal transmitted from the beacon terminal,
an acquisition unit that acquires a Received Signal Strength Indication of the beacon signal in each of a plurality of scanners that receive the beacon signal;
a determination unit that determines an instantaneous value of a Received Signal Strength Indication at a predetermined time point of a target scanner among the plurality of scanners to be an abnormal value when all of a plurality of conditions including a first condition, a second condition, and a third condition are satisfied;
A positioning unit that determines the position of the beacon terminal based on two or more Received Signal Strength Indications excluding the Received Signal Strength Indication determined to be the abnormal value by the determination unit,
the first condition is a condition that a value obtained by subtracting a first average value, which is an average value of Received Signal Strength Indication of a predetermined target scanner among the multiple scanners during a first period before or including the predetermined time point, from the instantaneous value of Received Signal Strength Indication of the scanner of interest at the predetermined time point is greater than a threshold value;
the second condition is a condition that, for the scanner of interest, the first average value is smaller than a second average value that is an average value of Received Signal Strength Indications for a second period prior to the first period;
the third condition is that, for a scanner having the largest first average value among the plurality of scanners, the first average value is larger than the second average value;
Positioning system.