Positioning device, positioning method, and program

Abstract

The present disclosure relates to a position measurement device, a position measurement method, and a program which make it possible to further improve position measurement accuracy. A distance measurement value calculation unit calculates, on the basis of communications for distance measurement that are performed between a communication terminal and a plurality of communication devices, a distance measurement value which indicates the distance between the communication terminal and each of the plurality of communication devices. A reliability calculation unit calculates the reliability of the distance measurement value. A weight control unit performs weight control for changing, in accordance with the reliability, a weight with respect to a first measurement position that is obtained from the distance measurement value. A position measurement calculation unit uses the first measurement position that has been weighted in accordance with the weight control and a second measurement position that is obtained by use of another position measurement technique to perform position measurement calculation for obtaining a third measurement position which is output as a result of measuring the position of the communication terminal. This technique can be applied to, for example, a distance measurement system that uses UWB.

Description

[Technical Field]

[0001] The present disclosure relates to a positioning device, a positioning method, and a program, and more particularly to a positioning device, a positioning method, and a program that are capable of further improving positioning accuracy. [Background technology]

[0002] Conventionally, development of positioning systems that measure the position of a user using distance measurement communications in accordance with the UWB (Ultra Wide Band) standard has been progressing, and various technologies have been proposed to improve positioning accuracy.

[0003] For example, Patent Document 1 proposes a technology for estimating a position based on the distance to a peripheral device selected based on an overall accuracy calculated from a position accuracy, which is the accuracy of the position, and a distance accuracy, which is the accuracy of the distance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 003353 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, the above-mentioned Patent Document 1 states that the smaller the values ​​of the position accuracy and distance accuracy, the higher the positioning accuracy. However, since the reliability of the position and distance is not taken into consideration in the first place, it is considered to be insufficient to determine whether the estimated position is correct.

[0006] The present disclosure has been made in consideration of such circumstances, and aims to further improve positioning accuracy. [Means for solving the problem]

[0007] A positioning device according to one aspect of the present disclosure includes: a distance measurement value calculation unit that calculates distance measurement values ​​indicating distances between each of a plurality of communication devices and a communication terminal based on distance measurement communications between the plurality of communication devices and the communication terminal; a reliability calculation unit that calculates reliability for the distance measurement values; a weight control unit that performs weight control to change a weight for a first position measurement position obtained from the distance measurement values ​​according to the reliability; and a positioning calculation unit that performs positioning calculation to obtain a third position measurement position to be output as a positioning result of the communication terminal using the first position measurement position weighted according to the weight control and a second position measurement position obtained using a positioning technology other than the positioning technology using the distance measurement communications. If the first positioning position is not within an area surrounded by multiple communication devices, the positioning calculation unit performs positioning calculation to determine the third positioning position by weighting the first positioning position so that the weight for the first positioning position is smaller.

[0008] A positioning method or program according to one aspect of the present disclosure includes: calculating a distance measurement value indicating a distance between each of a plurality of communication devices and a communication terminal based on communication for distance measurement performed between the plurality of communication devices and the communication terminal; calculating reliability of the distance measurement value; performing weight control to change a weight for a first position measurement position obtained from the distance measurement value according to the reliability; and performing positioning calculation to obtain a third position measurement position to be output as a position measurement result of the position of the communication terminal using the first position measurement position weighted according to the weight control and a second position measurement position obtained using a position measurement technology other than the position measurement technology using the communication for distance measurement. If the first determined position is not within a range surrounded by a plurality of the communication devices, a weight is assigned to the first determined position so as to decrease the weight, and a positioning calculation is performed to obtain the third determined position.

[0009] In one aspect of the present disclosure, a ranging value indicating the distance between each of the multiple communication devices and the communication terminal is calculated based on ranging communications performed between the multiple communication devices and the communication terminal, a reliability for the ranging value is calculated, and weight control is performed to change the weight for a first positioning position obtained from the ranging value according to the reliability, and a positioning calculation is performed to obtain a third positioning position to be output as a positioning result for the position of the communication terminal using the first positioning position weighted according to the weighting control and a second positioning position obtained using a positioning technology other than a positioning technology using ranging communications. If the first determined position is not within an area surrounded by a plurality of communication devices, a positioning calculation is performed to obtain a third determined position by weighting the first determined position so that the weight is reduced. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating an example of the configuration of an embodiment of a positioning system to which the present technology is applied. [Figure 2] FIG. 2 is a diagram illustrating a direct wave and a reflected wave. [Figure 3] FIG. 2 is a block diagram illustrating an example of the configuration of a mobile terminal. [Figure 4] FIG. 10 is a diagram illustrating a received signal profile. [Figure 5] 10 is a flowchart illustrating a positioning process using a received signal profile. [Figure 6] 10 is a flowchart illustrating a positioning process using the variance of distance measurement values. [Figure 7] 10 is a flowchart illustrating a positioning process using a communication success rate. [Figure 8] 10 is a flowchart illustrating a positioning process using an error correction rate. [Figure 9] 1 is a block diagram illustrating an example of the configuration of an embodiment of a computer to which the present technology is applied. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, specific embodiments to which the present technology is applied will be described in detail with reference to the drawings.

[0012] <Positioning system configuration example> FIG. 1 is a diagram showing an example of the configuration of an embodiment of a positioning system to which the present technology is applied.

[0013] The positioning system 11 shown in FIG. 1 is configured by connecting UWB anchors 12-1 to 12-4 and a ranging server 13, and is capable of locating the position of a user who possesses a mobile terminal .

[0014] 1 shows an example of a use case of positioning system 11 in which, for example, attendance management is performed using location information of users carrying mobile terminals 14 in a room such as an office where UWB anchors 12-1 to 12-4 are installed. In addition to this use case, positioning system 11 is expected to be used in other use cases, such as analyzing customer behavior, presenting real-time advertisements or product information, navigating customers in a store, visualizing employee behavior and improving operations, and streamlining the PDCA (Plan-Do-Check-Action) cycle.

[0015] Under the control of ranging server 13, UWB anchors 12-1 to 12-4 perform distance measurement communication (hereinafter referred to as UWB distance measurement communication) with mobile terminal 14 in accordance with the UWB standard.

[0016] The ranging server 13 performs various controls necessary for the UWB anchors 12-1 to 12-4 to perform UWB ranging communication. For example, the ranging server 13 controls the timing at which each of the UWB anchors 12-1 to 12-4 communicates with the mobile terminal 14 in UWB ranging communication.

[0017] The mobile terminal 14 can obtain distance measurements indicating the distance to each of the UWB anchors 12-1 to 12-4 by performing UWB ranging communications with the UWB anchors 12-1 to 12-4, and can perform positioning processing to determine the position of the mobile terminal 14 from these distance measurements. Hereinafter, the current position of the mobile terminal 14 obtained by calculation based on the UWB ranging communications will be referred to as the UWB determined position.

[0018] For example, in UWB ranging communication in the positioning system 11, ranging commands and responses are transmitted and received by electromagnetic waves between the UWB anchor 12 and the mobile terminal 14. Then, based on the transmission timing and reception timing of the ranging command and the transmission timing and reception timing of the ranging response, the measured distance between the UWB anchor 12 and the mobile terminal 14 can be calculated. Then, when the measured distances between at least three or more UWB anchors 12 are obtained, the intersection of circles with each UWB anchor 12 as the center and the measured distance as the radius can be calculated as the UWB positioning position of the mobile terminal 14.

[0019] At this time, as shown in FIG. 2, the mobile terminal 14 may receive electromagnetic waves directly from the UWB anchor 12, or may receive electromagnetic waves that have been output from the UWB anchor 12 and reflected by metal or the like. When such a phenomenon occurs, it is expected that the signals received by the mobile terminal 14 may conflict, making it difficult to stably obtain distance measurements using UWB. A similar phenomenon may also occur when the UWB anchor 12 receives electromagnetic waves output from the mobile terminal 14. Furthermore, it is expected that the UWB anchor 12 or the mobile terminal 14 may not be able to properly receive direct electromagnetic waves due to the influence of radio wave absorption by the human body, for example.

[0020] Therefore, the positioning system 11 is configured to be able to determine the determined position based on positioning processing using various positioning technologies in addition to the positioning technology using UWB. The positioning system 11 controls the weighting of the determined position based on these positioning technologies depending on the reliability of the distance measurement value using UWB, thereby improving the positioning accuracy of the determined position that is ultimately determined as the positioning result of the position of the mobile terminal 14.

[0021] FIG. 3 is a block diagram showing an example of the configuration of the mobile terminal 14.

[0022] As shown in Figure 3, the mobile terminal 14 is configured to include a geomagnetic sensor 21, an acceleration sensor 22, a gyro 23, a UWB communication unit 24, a PDR processing unit 25, a UWB distance measurement value calculation unit 26, a reliability calculation unit 27, a weight control unit 28, and a positioning calculation unit 29.

[0023] The geomagnetic sensor 21 detects the geomagnetism at the current position of the mobile terminal 14 and supplies the detected value to the positioning calculation unit 29. The acceleration sensor 22 detects the acceleration of the mobile terminal 14 and supplies the detected value to the PDR processing unit 25. The gyro 23 detects the angular velocity of the mobile terminal 14 and supplies the detected value to the PDR processing unit 25.

[0024] The UWB communication unit 24 can communicate in accordance with the UWB standard. For example, the UWB communication unit 24 performs UWB ranging communication to transmit and receive ranging commands and responses to each of the UWB anchors 12-1 to 12-4. The UWB communication unit 24 then acquires the transmission and reception timings of each ranging command and each ranging response, and supplies these to the UWB ranging value calculation unit 26.

[0025] The PDR processing unit 25 can determine the current position of the mobile terminal 14 by performing PDR (Pedestrian Dead Reckoning) processing using the acceleration of the mobile terminal 14 supplied from the acceleration sensor 22 and the angular velocity of the mobile terminal 14 supplied from the gyro 23. Then, the PDR processing unit 25 supplies the current position of the mobile terminal 14 determined by the PDR processing (hereinafter referred to as the PDR determined position) to the positioning calculation unit 29.

[0026] The UWB distance measurement value calculation unit 26 calculates the distance measurement value between each of the UWB anchors 12-1 to 12-4 based on the transmission timing and reception timing of the distance measurement command and the transmission timing and reception timing of the distance measurement response supplied from the UWB communication unit 24, and supplies the calculated distance value to the positioning calculation unit 29.

[0027] The reliability calculation unit 27 calculates the reliability of the distance measurement value calculated by the UWB distance measurement value calculation unit 26 and supplies the reliability to the weight control unit 28. For example, as will be described later, the reliability calculation unit 27 can calculate the received signal profile, the variance of the distance measurement value, the communication success rate, or the error correction rate as the reliability of the distance measurement value using UWB.

[0028] Weight control unit 28 performs weight control to change the weight for the UWB positioning position used when positioning calculation unit 29 performs positioning calculation, according to the reliability supplied from reliability calculation unit 27. For example, weight control unit 28 performs weight control to increase the weight for the UWB positioning position if the reliability of the distance measurement value using UWB is high, and performs weight control to decrease the weight for the UWB positioning position if the reliability of the distance measurement value using UWB is low.

[0029] The positioning calculation unit 29 determines the UWB positioning position based on the UWB distance measurement values ​​between the mobile terminal 14 and each of the UWB anchors 12-1 to 12-4, which are supplied from the UWB distance measurement value calculation unit 26. The positioning calculation unit 29 also references a geomagnetic map acquired in advance and determines the current position of the mobile terminal 14 according to the geomagnetism supplied from the geomagnetic sensor 21 (hereinafter referred to as the geomagnetically determined position). The positioning calculation unit 29 then performs positioning calculation to determine the current position of the mobile terminal 14, which is to be output as a positioning result, using the UWB positioning position weighted according to the weight control by the weight control unit 28, the PDR positioning position, and the geomagnetically determined position.

[0030] As described above, the mobile terminal 14 is configured so that if the reliability of the distance measurement value using UWB is high, the positioning result obtained will have a high contribution rate of the UWB-measured position relative to the PDR-measured position and the geomagnetic-measured position. On the other hand, if the reliability of the distance measurement value using UWB is low, the positioning result obtained will have a low contribution rate of the UWB-measured position relative to the PDR-measured position and the geomagnetic-measured position.

[0031] In this way, the mobile terminal 14 can improve the positioning accuracy of the positioning position output as the positioning result of the mobile terminal 14 by performing positioning processing that controls the weighting for the UWB positioning position based on the reliability of the distance measurement value using UWB.

[0032] <Example of positioning processing with weight control> With reference to FIGS. 4 to 8, a positioning process in which weights are controlled based on the reliability of distance measurements using UWB will be described.

[0033] FIG. 4 is a diagram illustrating a received signal profile used as the reliability of a distance measurement value using UWB.

[0034] As described above with reference to Fig. 2, the mobile terminal 14 receives direct waves and reflected waves when performing UWB ranging communication with the UWB anchor 12. The average power of the received signal (ranging packet) received by the mobile terminal 14 in UWB ranging communication is usually higher for the direct wave and lower for the reflected wave. The mobile terminal 14 receives the direct wave first and then the reflected wave.

[0035] Therefore, if the reception conditions are good, a reception signal profile is generated in which the average power of the reception signal of the direct wave, which is received first, is high and the average power of the reception signal of the reflected wave, which is received later, is low, as shown in A of Figure 4.

[0036] On the other hand, as shown in Fig. 4B, if there is no large difference between the average power of the received signal of the direct wave and the noise level, it can be determined that the reception conditions are not good and that there is a high possibility that the UWB communication unit 24 is not able to receive the direct wave. Also, as shown in Fig. 4C, if the average power of the received signal of the direct wave is lower than the average power of the received signal of the reflected wave, it can be determined that there is a high possibility that the reception conditions are not good and that the UWB communication unit 24 is not able to receive the direct wave.

[0037] Therefore, if the reception conditions of the received signal in the UWB ranging communication are good, for example, if the reception signal profile is as shown in A of Fig. 4, the weight control unit 28 determines that the reliability of the ranging value using UWB is high and performs weight control to increase the weight for the UWB positioning position. On the other hand, if the reception conditions of the received signal in the UWB ranging communication are not good, for example, if the reception signal profile is as shown in B or C of Fig. 4, the weight control unit 28 determines that the reliability of the ranging value using UWB is low and performs weight control to decrease the weight for the UWB positioning position.

[0038] FIG. 5 is a flowchart illustrating a positioning process using a received signal profile as the reliability of a distance measurement value using UWB.

[0039] In step S11, the UWB communication unit 24 performs UWB ranging communication with the UWB anchors 12-1 to 12-4. The UWB communication unit 24 acquires the timings of sending and receiving commands for ranging and the timings of sending and receiving responses for ranging between the UWB anchors 12-1 to 12-4 and supplies these to the UWB ranging value calculation unit 26. The UWB ranging value calculation unit 26 then calculates the ranging values ​​between the UWB anchors 12-1 to 12-4 and the UWB anchors 12-1 to 12-4 based on the timings of sending and receiving commands for ranging and responses for ranging.

[0040] In step S12, the reliability calculation unit 27 acquires the average power of the received signal received by the UWB communication unit 24 in the UWB ranging communication in step S11 from the UWB communication unit 24. Then, the reliability calculation unit 27 calculates a received signal profile (see FIG. 4) represented by the average power and the reception time of the received signal as the reliability of the ranging value using UWB.

[0041] In step S13, the weight control unit 28 performs weight control to change the weight for weighting the UWB positioning position in accordance with the received signal profile calculated by the reliability calculation unit 27 in step S12.

[0042] In step S14, the positioning calculation unit 29 calculates a UWB positioning position based on the ranging value calculated by the UWB ranging value calculation unit 26 in step S11, and weights the UWB positioning position with the weight controlled by the weight control unit 28 in step S13. The positioning calculation unit 29 also acquires the PDR positioning position calculated by the PDR processing unit 25, and calculates a geomagnetic positioning position according to the geomagnetism supplied from the geomagnetic sensor 21. Then, the positioning calculation unit 29 performs positioning calculation to calculate the current position of the mobile terminal 14, which is to be output as a positioning result, using the weighted UWB positioning position, the PDR positioning position, and the geomagnetic positioning position.

[0043] As described above, the mobile terminal 14 uses the received signal profile as a measure of the reliability of the distance measurement value using UWB, and controls the weight for the UWB positioning position depending on whether the reception conditions of the received signal in the UWB ranging communication are good or not, thereby improving the positioning accuracy. For example, when the reception conditions of the received signal in the UWB ranging communication are not good, the mobile terminal 14 controls the weight so that the weight for the UWB positioning position becomes smaller, thereby reducing the contribution rate of the UWB positioning position to the positioning result and preventing a decrease in the positioning accuracy.

[0044] The reliability calculation unit 27 may acquire from the UWB anchors 12-1 to 12-4 the received signal profiles obtained when the UWB anchors 12-1 to 12-4 performed UWB ranging communication with the UWB communication unit 24. The weight control unit 28 can then refer to not only the received signal profile of the UWB communication unit 24 but also the received signal profiles of the UWB anchors 12-1 to 12-4, and use all of these to comprehensively determine whether the reception conditions are good or not.

[0045] FIG. 6 is a flowchart illustrating a positioning process using the variance of the distance measurement values ​​as the reliability of the distance measurement values ​​using UWB.

[0046] In step S21, the UWB communication unit 24 performs UWB ranging communication with the UWB anchors 12-1 to 12-4. The UWB communication unit 24 acquires the timings of transmission and reception of ranging commands and ranging responses between the UWB communication unit 24 and each of the UWB anchors 12-1 to 12-4, and supplies these to the UWB ranging value calculation unit 26. The UWB ranging value calculation unit 26 then calculates the ranging values ​​between the UWB anchors 12-1 to 12-4 based on the timings of transmission and reception of the ranging commands and ranging responses. The reliability calculation unit 27 then acquires the ranging values ​​calculated by the UWB ranging value calculation unit 26.

[0047] In step S22, the reliability calculation unit 27 determines whether or not distance measurement values ​​have been acquired a specified number of times. If the reliability calculation unit 27 determines in step S22 that distance measurement values ​​have not been acquired a specified number of times, the process proceeds to step S23.

[0048] In step S23, the reliability calculation unit 27 determines whether or not the UWB ranging communication in step S21 has exceeded a specified number of communications. If the reliability calculation unit 27 determines in step S23 that the UWB ranging communication in step S21 has not exceeded the specified number of communications, the process returns to step S21, and the same processes are repeated thereafter.

[0049] On the other hand, if it is determined in step S22 that the specified number of distance measurement values ​​have been acquired, or if it is determined in step S23 that the specified number of communications has been exceeded, the process proceeds to step S24. That is, UWB distance measurement communication is repeated until the specified number of distance measurement values ​​have been acquired, and even if the specified number of distance measurement values ​​have not been acquired, UWB distance measurement communication is repeated until the specified number of communications has been reached.

[0050] In step S24, the reliability calculation unit 27 calculates the variance of the multiple distance measurements obtained by repeatedly performing UWB distance measurement communication as the reliability of the distance measurements using UWB. Also, the UWB distance measurement value calculation unit 26 can calculate the average value of the multiple distance measurements and supply the average value to the positioning calculation unit 29.

[0051] In step S25, the weight control unit 28 performs weight control to change the weight for weighting the UWB positioning position in accordance with the variance of the distance measurement values ​​calculated by the reliability calculation unit 27 in step S24.

[0052] For example, if the variance of the ranging values ​​calculated by the reliability calculation unit 27 does not exceed a predetermined threshold, the weight control unit 28 can determine that the positioning values ​​using UWB are being obtained stably, and performs weight control so as to increase the weight for the UWB-measured position. On the other hand, if the variance of the ranging values ​​calculated by the reliability calculation unit 27 exceeds a predetermined threshold, the weight control unit 28 can determine that the positioning values ​​using UWB are not being obtained stably, and performs weight control so as to decrease the weight for the UWB-measured position. Note that the weight control unit 28 may perform weight control using a predetermined threshold, or may perform weight control such that a value corresponding to the variance of the ranging values ​​is used as a weight.

[0053] In step S26, the positioning calculation unit 29 performs positioning calculation to determine the current position of the mobile terminal 14 to be output as the positioning result, using the weighted UWB positioning position, the PDR positioning position, and the geomagnetic positioning position, as described in step S14 of Figure 5.

[0054] As described above, the mobile terminal 14 uses the variance of the ranging values ​​as a measure of the reliability of the ranging values ​​using UWB to control the weighting of the UWB-measured position depending on whether the positioning values ​​are being obtained stably, thereby improving the positioning accuracy. For example, when the positioning values ​​are not being obtained stably, the mobile terminal 14 performs weighting control so as to reduce the weighting of the UWB-measured position, thereby reducing the contribution rate of the UWB-measured position to the positioning result, thereby preventing a decrease in the positioning accuracy.

[0055] FIG. 7 is a flowchart illustrating a positioning process using a communication success rate as the reliability of a distance measurement value using UWB.

[0056] In step S31, the UWB communication unit 24 performs UWB ranging communication with the UWB anchors 12-1 to 12-4. If the UWB ranging communication is successful, the UWB communication unit 24 acquires the transmission and reception timings of the ranging command and the transmission and reception timings of the ranging response between the UWB anchors 12-1 to 12-4 and supplies them to the UWB ranging value calculation unit 26. The UWB ranging value calculation unit 26 then calculates the ranging value between the UWB anchors 12-1 to 12-4 and the UWB anchors 12-1 to 12-4 based on the transmission and reception timings of the ranging command and the transmission and reception timings of the ranging response. If the UWB ranging communication is unsuccessful, the UWB communication unit 24 can repeatedly attempt UWB ranging communication.

[0057] In step S32, the UWB communication unit 24 determines whether the number of successful UWB ranging communications in step S31 has exceeded a specified number of communications. If the UWB communication unit 24 determines in step S32 that the number of successful UWB ranging communications in step S31 has not exceeded the specified number of communications, the process returns to step S31, and the same processes are repeated thereafter.

[0058] On the other hand, if the UWB communication unit 24 determines in step S32 that the number of successful UWB ranging communications in step S31 exceeds the specified number of communications, the process proceeds to step S33.

[0059] In step S33, the UWB communication unit 24 supplies the number of attempts of UWB ranging communication in step S31 and the number of successful UWB ranging communication to the reliability calculation unit 27. Then, the reliability calculation unit 27 calculates the communication success rate of successful UWB ranging communication as the reliability of the ranging value using UWB.

[0060] In step S34, the weight control unit 28 performs weight control to change the weight for weighting the UWB positioning position in accordance with the communication success rate calculated by the reliability calculation unit 27 in step S33.

[0061] For example, if the communication success rate calculated by the reliability calculation unit 27 exceeds a predetermined threshold, the weight control unit 28 can determine that the UWB ranging communication is being performed stably, and performs weight control so as to increase the weight for the UWB positioning position. On the other hand, if the communication success rate calculated by the reliability calculation unit 27 does not exceed the predetermined threshold, the weight control unit 28 can determine that the UWB ranging communication is not being performed stably, and performs weight control so as to decrease the weight for the UWB positioning position. Note that the weight control unit 28 may perform weight control using a predetermined threshold, or may perform weight control using a value corresponding to the communication success rate as the weight, for example.

[0062] In step S35, the positioning calculation unit 29 performs positioning calculation to determine the current position of the mobile terminal 14 to be output as the positioning result, using the weighted UWB positioning position, the PDR positioning position, and the geomagnetic positioning position, as described in step S14 of Figure 5.

[0063] As described above, the mobile terminal 14 uses the communication success rate as a measure of the reliability of the ranging value using UWB and controls the weight for the UWB-measured position depending on whether the UWB ranging communication is being performed stably, thereby improving the positioning accuracy. For example, when the UWB ranging communication is not being performed stably, the mobile terminal 14 performs weight control so as to reduce the weight for the UWB-measured position, thereby reducing the contribution rate of the UWB-measured position to the positioning result, thereby preventing a decrease in the positioning accuracy.

[0064] FIG. 8 is a flowchart illustrating a positioning process using an error correction rate as the reliability of a distance measurement value using UWB.

[0065] In step S41, the UWB communication unit 24 performs UWB ranging communication with the UWB anchors 12-1 to 12-4 with a data communication packet added. At this time, the UWB communication unit 24 demodulates the data communication packet transmitted from the UWB anchors 12-1 to 12-4 in the UWB ranging communication, and if an error occurs in the data stored in the packet, the UWB communication unit 24 can correct the data error by applying an error correction code.

[0066] Then, the UWB communication unit 24 acquires the timings of transmission and reception of commands for ranging and the timings of transmission and reception of responses for ranging between the UWB anchors 12-1 to 12-4 and each of them, and supplies these to the UWB ranging value calculation unit 26. As a result, the UWB ranging value calculation unit 26 calculates the ranging values ​​between the UWB anchors 12-1 to 12-4 and each of them, based on the timings of transmission and reception of commands for ranging and the timings of transmission and reception of responses for ranging.

[0067] In step S42, the UWB communication unit 24 determines whether the UWB ranging communication in step S41 has exceeded the specified number of communications. If the UWB communication unit 24 determines in step S42 that the UWB ranging communication in step S41 has not exceeded the specified number of communications, the process returns to step S41, and the same processes are repeated thereafter.

[0068] On the other hand, if the UWB communication unit 24 determines in step S42 that the UWB ranging communication in step S41 has exceeded the specified number of communications, the process proceeds to step S43.

[0069] In step S43, the UWB communication unit 24 supplies the amount of data stored in all data communication packets received in the UWB ranging communication in step S41 and the amount of data in which errors occurred to the reliability calculation unit 27. Then, the reliability calculation unit 27 calculates a data error correction rate (a rate indicating how many errors occurred in the data stored in the data communication packets) as the reliability of the ranging value using UWB.

[0070] In step S44, the weight control unit 28 performs weight control to change the weight for weighting the UWB positioning position in accordance with the error correction rate calculated by the reliability calculation unit 27 in step S43.

[0071] For example, if the error correction rate calculated by the reliability calculation unit 27 exceeds a predetermined threshold, the weight control unit 28 can determine that the communication conditions of the UWB ranging communication are not good, and performs weight control so as to reduce the weight for the UWB positioning position. On the other hand, if the error correction rate calculated by the reliability calculation unit 27 does not exceed the predetermined threshold, the weight control unit 28 can determine that the communication conditions of the UWB ranging communication are good, and performs weight control so as to increase the weight for the UWB positioning position. Note that the weight control unit 28 may perform weight control using a predetermined threshold, or may perform weight control using a value corresponding to the error correction rate as the weight, for example.

[0072] In step S45, the positioning calculation unit 29 performs positioning calculation to determine the current position of the mobile terminal 14 to be output as the positioning result, using the weighted UWB positioning position, the PDR positioning position, and the geomagnetic positioning position, as described in step S14 of Figure 5.

[0073] As described above, the mobile terminal 14 can improve the positioning accuracy by controlling the weight for the UWB positioning position depending on whether the UWB ranging communication is stable or not, using the error correction rate as the reliability of the ranging value using UWB. For example, when the communication conditions of the UWB ranging communication are not good, the mobile terminal 14 controls the weight so that the weight for the UWB positioning position becomes smaller, thereby reducing the contribution rate of the UWB positioning position to the positioning result and preventing a decrease in the positioning accuracy.

[0074] The reliability calculation unit 27 may acquire from the UWB anchors 12-1 to 12-4 the error correction rates when the UWB anchors 12-1 to 12-4 perform UWB ranging communication with the UWB communication unit 24. The weight control unit 28 can refer to not only the error correction rate of the UWB communication unit 24 but also the error correction rates of the UWB anchors 12-1 to 12-4, and use all of these to comprehensively determine whether the communication conditions of the UWB ranging communication are good.

[0075] As described above, the positioning system 11 performs weight control using the received signal profile, the variance of the measured distance, the communication success rate, or the error correction rate to determine the reliability of the UWB-based distance measurement value, thereby improving the accuracy and stability of the positioning. The received signal profile, the variance of the measured distance, the communication success rate, or the error correction rate may be used individually or in combination for weight control. Furthermore, weight control can be performed not only on the UWB-based position but also on the PDR-based position or the geomagnetically-based position.

[0076] Furthermore, in the positioning system 11, for example, if the reliability of at least three or more of the multiple distance measurements is high, i.e., if three or more highly reliable distance measurements can be obtained using UWB, weight control may be performed so that the weight assigned to the UWB-measured position is increased. In other words, in this case, the intersection of a circle with the three most reliable distance measurements as its radius can be determined to be sufficiently reliable as the UWB-measured position of the mobile terminal 14, and positioning processing can be performed without using less reliable distance measurements. Of course, if three or more highly reliable distance measurements cannot be obtained using UWB, weight control is performed so that the weight assigned to the UWB-measured position is decreased.

[0077] Note that the present technology can be applied not only to the positioning process using two-way ranging as described above, but also to positioning process using a one-way ranging method (TDoA: Time Difference of Arrival), for example.

[0078] For example, in a positioning process using TDoA, methods for detecting that the distance measurement value or the positioning result is unreliable include the received signal profile, the variance of the distance measurement value, the communication success rate, or the error correction rate, as well as whether the UWB-measured position of the mobile terminal 14 is within the area surrounded by UWB anchors 12-1 to 12-4. That is, if the UWB-measured position of the mobile terminal 14 is not within the area surrounded by UWB anchors 12-1 to 12-4 (if it is outside the area), it has been proven in principle that the reliability of the UWB-measured position may be low.

[0079] Therefore, if the UWB-measured position of mobile terminal 14 is not within the area surrounded by UWB anchors 12-1 to 12-4, weight control is performed so that the weight for that UWB-measured position is reduced. Note that weight control for the UWB-measured position determined by the positioning process using TDoA is not performed in weight control unit 28 as described with reference to Fig. 3, but is performed inside positioning calculation unit 29, which determines the UWB-measured position. In other words, positioning calculation unit 29 weights the UWB-measured position of mobile terminal 14 based on whether the UWB-measured position of mobile terminal 14 is within the area surrounded by UWB anchors 12-1 to 12-4, and can perform positioning calculation to determine the current position of mobile terminal 14 to be output as the positioning result.

[0080] Furthermore, in the positioning system 11, in addition to performing the positioning process as described above in the mobile terminal 14, the positioning process can also be configured to be performed in the ranging server 13 that controls UWB ranging communications by the UWB anchors 12-1 to 12-4. In this case, the received signal profile, communication success rate, and error correction rate determined in the mobile terminal 14 may be supplied from the mobile terminal 14 to the ranging server 13. Also, the geomagnetism detected by the geomagnetic sensor 21, the acceleration detected by the acceleration sensor 22, and the angular velocity detected by the gyro 23 may be supplied from the mobile terminal 14 to the ranging server 13, and the positioning process may be performed in the ranging server 13.

[0081] <Example of computer configuration> Next, the above-described series of processes (positioning method) can be performed by hardware or software. When the series of processes is performed by software, a program constituting the software is installed in a general-purpose computer or the like.

[0082] FIG. 9 is a block diagram showing an example of the configuration of an embodiment of a computer in which a program for executing the above-described series of processes is installed.

[0083] The program can be recorded in advance on the hard disk 105 or ROM 103 as a recording medium built into the computer.

[0084] Alternatively, the program can be stored (recorded) on a removable recording medium 111 driven by the drive 109. Such a removable recording medium 111 can be provided as a so-called package software. Here, examples of the removable recording medium 111 include a flexible disk, a CD-ROM (Compact Disc Read Only Memory), an MO (Magneto Optical) disk, a DVD (Digital Versatile Disc), a magnetic disk, and a semiconductor memory.

[0085] The program can be installed into the computer from the removable recording medium 111 as described above, or can be downloaded to the computer via a communication network or a broadcasting network and installed on the built-in hard disk 105. That is, the program can be transferred to the computer wirelessly from a download site via an artificial satellite for digital satellite broadcasting, or transferred to the computer by wire via a network such as a LAN (Local Area Network) or the Internet.

[0086] The computer includes a CPU (Central Processing Unit) 102 , to which an input / output interface 110 is connected via a bus 101 .

[0087] When a user inputs a command by operating input unit 107 via input / output interface 110, CPU 102 executes a program stored in ROM (Read Only Memory) 103 in accordance with the command. Alternatively, CPU 102 loads a program stored on hard disk 105 into RAM (Random Access Memory) 104 and executes it.

[0088] As a result, CPU 102 performs processing according to the flowchart described above or processing performed by the configuration of the block diagram described above. CPU 102 then outputs the processing results from output unit 106 via input / output interface 110, transmits them from communication unit 108, or records them on hard disk 105, as necessary.

[0089] The input unit 107 is made up of a keyboard, a mouse, a microphone, etc. The output unit 106 is made up of an LCD (Liquid Crystal Display), a speaker, etc.

[0090] In this specification, the processing performed by a computer according to a program does not necessarily have to be performed in chronological order according to the order described in the flowchart. In other words, the processing performed by a computer according to a program also includes processing that is executed in parallel or individually (for example, parallel processing or processing by objects).

[0091] The program may be processed by a single computer (processor), or may be distributed among multiple computers. Furthermore, the program may be transferred to and executed on a remote computer.

[0092] Furthermore, in this specification, a system refers to a collection of multiple components (devices, modules (components), etc.), regardless of whether all the components are contained in the same housing. Therefore, multiple devices housed in separate housings and connected via a network, and a single device housed in a single housing with multiple modules, are both systems.

[0093] Also, for example, a configuration described as one device (or processing unit) may be divided and configured as multiple devices (or processing units). Conversely, configurations described above as multiple devices (or processing units) may be combined and configured as one device (or processing unit). Of course, configurations other than those described above may be added to the configuration of each device (or each processing unit). Furthermore, as long as the configuration and operation of the entire system are substantially the same, part of the configuration of one device (or processing unit) may be included in the configuration of another device (or other processing unit).

[0094] Furthermore, for example, this technology can be configured as a cloud computing system in which a single function is shared and processed collaboratively by multiple devices via a network.

[0095] Furthermore, for example, the above-described program can be executed in any device, as long as the device has the necessary functions (functional blocks, etc.) and can obtain the necessary information.

[0096] Also, for example, each step described in the above flowchart can be executed by one device or can be shared and executed by multiple devices. Furthermore, if one step includes multiple processes, the multiple processes included in that one step can be executed by one device or can be shared and executed by multiple devices. In other words, multiple processes included in one step can be executed as multiple step processes. Conversely, processes described as multiple steps can be executed collectively as one step.

[0097] In addition, the processing of the steps of a program executed by a computer may be executed in chronological order according to the order described in this specification, or may be executed in parallel or individually at the required timing, such as when a call is made. In other words, as long as no contradiction occurs, the processing of each step may be executed in an order different from the order described above. Furthermore, the processing of the steps of this program may be executed in parallel with the processing of another program, or may be executed in combination with the processing of another program.

[0098] It should be noted that the present technologies described in this specification can be implemented independently and singly, unless a contradiction arises. Of course, any two or more of the present technologies can also be implemented in combination. For example, part or all of the present technologies described in any embodiment can be implemented in combination with part or all of the present technologies described in other embodiments. Furthermore, part or all of any of the present technologies described above can also be implemented in combination with other technologies not described above.

[0099] <Configuration combination example> The present technology can also be configured as follows. (1) a distance measurement value calculation unit that calculates a distance measurement value indicating a distance between each of a plurality of communication devices and the communication terminal based on distance measurement communications performed between the plurality of communication devices and the communication terminal; a reliability calculation unit that calculates the reliability of the distance measurement value; a weight control unit that performs weight control to change a weight for the first positioning position obtained from the distance measurement value according to the reliability; a positioning calculation unit that performs positioning calculation to obtain a third positioning position to be output as a positioning result of the position of the communication terminal, using the first positioning position weighted according to the weight control and a second positioning position obtained using a positioning technology other than the positioning technology using the communication for ranging; A positioning device comprising: (2) The reliability calculation unit calculates, as the reliability, a received signal profile represented by an average power and a reception time when the ranging signal is received. The positioning device according to (1) above. (3) The reliability calculation unit calculates, as the reliability, a variance of a plurality of the distance measurement values ​​obtained by performing a plurality of the distance measurement communications. The positioning device according to (1) or (2) above. (4) The reliability calculation unit calculates, as the reliability, a communication success rate indicating a success rate when a plurality of communications for distance measurement are performed. A positioning device according to any one of (1) to (3) above. (5) The distance measurement communication is performed with a data communication packet added, The reliability calculation unit calculates, as the reliability, a ratio indicating the degree of error that has occurred in the data stored in the packet for data communication. A positioning device according to any one of (1) to (4) above. (6) The weight control unit performs the weight control so that a weight for the first positioning position is increased when the reliability of at least three or more of the distance measurement values ​​is high. A positioning device according to any one of (1) to (5) above. (7) When the first determined position is not within a range surrounded by a plurality of the communication devices, the positioning calculation unit performs a positioning calculation to obtain the third determined position by weighting the first determined position so that a weight for the first determined position is reduced. A positioning device according to any one of (1) to (6) above. (8) The positioning technology utilizes distance measurement communications in accordance with the UWB (Ultra Wide Band) standard, The other positioning techniques are those that utilize geomagnetism or those that utilize acceleration and angular velocity. A positioning device according to any one of (1) to (7) above. (9) A positioning device that performs positioning processing, calculating a distance measurement value indicating a distance between each of a plurality of communication devices and the communication terminal based on distance measurement communications performed between the plurality of communication devices and the communication terminal; calculating a reliability of the distance measurement value; performing weight control to change a weight for the first positioning position calculated from the measured distance value according to the reliability; performing a positioning calculation to obtain a third measured position to be output as a positioning result of the position of the communication terminal, using the first measured position weighted according to the weight control and a second measured position obtained by using a positioning technique other than the positioning technique using the communication for distance measurement; A positioning method including: (10) The computer of the positioning device that performs the positioning process calculating a distance measurement value indicating a distance between each of a plurality of communication devices and the communication terminal based on distance measurement communications performed between the plurality of communication devices and the communication terminal; calculating a reliability of the distance measurement value; performing weight control to change a weight for the first positioning position calculated from the measured distance value according to the reliability; performing a positioning calculation to obtain a third measured position to be output as a positioning result of the position of the communication terminal, using the first measured position weighted according to the weight control and a second measured position obtained by using a positioning technique other than the positioning technique using the communication for distance measurement; A program for executing a positioning process including the above.

[0100] It should be noted that the present embodiment is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist of the present disclosure. Furthermore, the effects described in this specification are merely examples and are not intended to be limiting, and other effects may also be obtained. [Explanation of symbols]

[0101] 11 Positioning system, 12 UWB anchor, 13 Ranging server, 14 Mobile terminal, 21 Geomagnetic sensor, 22 Acceleration sensor, 23 Gyro, 24 UWB communication unit, 25 PDR processing unit, 26 UWB ranging value calculation unit, 27 Reliability calculation unit, 28 Weight control unit, 29 Positioning calculation unit

Claims

1. a distance measurement value calculation unit that calculates a distance measurement value indicating a distance between each of a plurality of communication devices and the communication terminal based on distance measurement communications performed between the plurality of communication devices and the communication terminal; a reliability calculation unit that calculates the reliability of the distance measurement value; a weight control unit that performs weight control to change a weight for the first positioning position obtained from the distance measurement value in accordance with the reliability; a positioning calculation unit that performs positioning calculation to obtain a third positioning position to be output as a positioning result of the position of the communication terminal, using the first positioning position weighted according to the weight control and a second positioning position obtained using a positioning technology other than the positioning technology using the communication for distance measurement; Equipped with When the first positioning position is not within a range surrounded by a plurality of the communication devices, the positioning calculation unit performs a positioning calculation to obtain the third positioning position by weighting the first positioning position so that a weight for the first positioning position is reduced. Positioning device.

2. The reliability calculation unit calculates, as the reliability, a received signal profile represented by an average power and a reception time when the ranging signal is received. The positioning device according to claim 1 .

3. The reliability calculation unit calculates, as the reliability, a variance of a plurality of the distance measurement values ​​obtained by performing a plurality of the distance measurement communications. The positioning device according to claim 1 .

4. The reliability calculation unit calculates, as the reliability, a communication success rate indicating a success rate when a plurality of communications for distance measurement are performed. The positioning device according to claim 1 .

5. The distance measurement communication is performed with a data communication packet added, The reliability calculation unit calculates, as the reliability, a ratio indicating the degree of error that has occurred in the data stored in the packet for data communication. The positioning device according to claim 1 .

6. The weight control unit performs the weight control so that a weight for the first positioning position is increased when the reliability of at least three or more of the distance measurement values ​​is high. The positioning device according to claim 1 .

7. The positioning technology utilizes distance measurement communications in accordance with the UWB (Ultra Wide Band) standard, The other positioning techniques are those that utilize geomagnetism or those that utilize acceleration and angular velocity. The positioning device according to claim 1 .

8. A positioning device that performs positioning processing, calculating a distance measurement value indicating a distance between each of a plurality of communication devices and the communication terminal based on distance measurement communications performed between the plurality of communication devices and the communication terminal; calculating a reliability of the distance measurement value; performing weight control to change a weight for the first positioning position calculated from the distance measurement value according to the reliability; performing a positioning calculation to obtain a third positioning position to be output as a positioning result of the position of the communication terminal, using the first positioning position weighted according to the weight control and a second positioning position obtained by using a positioning technique other than the positioning technique using the communication for distance measurement; Including, If the first determined position is not within a range surrounded by a plurality of the communication devices, a weighting is applied to the first determined position so as to decrease the weight, and a positioning calculation is performed to obtain the third determined position. Positioning method.

9. The computer of the positioning device that performs the positioning process calculating a distance measurement value indicating a distance between each of a plurality of communication devices and the communication terminal based on distance measurement communications performed between the plurality of communication devices and the communication terminal; calculating a reliability of the distance measurement value; performing weight control to change a weight for the first positioning position calculated from the distance measurement value according to the reliability; performing a positioning calculation to obtain a third positioning position to be output as a positioning result of the position of the communication terminal, using the first positioning position weighted according to the weight control and a second positioning position obtained by using a positioning technique other than the positioning technique using the communication for distance measurement; Including, If the first determined position is not within a range surrounded by a plurality of the communication devices, a weighting is applied to the first determined position so as to decrease the weight, and a positioning calculation is performed to obtain the third determined position. A program for executing positioning processing.

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