Positioning system, distance measuring device, and positioning device

Abstract

An objective of the present invention is to suppress deterioration in the accuracy of positioning performed by a terminal and based on distance measurements between a plurality of distance measuring devices and the terminal.　A positioning system includes: a terminal capable of wireless communication; a plurality of distance measuring devices for measuring the distance to the terminal on the basis of wireless communication with the terminal; and a positioning server for performing positioning of the terminal on the basis of the results of distance measurements between the terminal and distance measuring devices selected on the basis of lines of sight between the distance measuring devices. The distance measuring devices include: a radio communication circuit for performing radio communication with the terminal; a distance measuring circuit for measuring the distance to the terminal on the basis of the results of radio communication with the terminal; and a sensor for detecting the lines of sight between the distance measuring devices. The sensor detects the surrounding environment of the distance measuring device.

Description

Positioning systems, ranging devices and positioning devices

[0001] The present technology relates to a positioning system, a ranging device, and a positioning device. More specifically, the present technology relates to a positioning system, a ranging device, and a positioning device in which line-of-sight between ranging devices is used for positioning.

[0002] In wireless communication between a mobile communication device and a fixed communication device, the timing at which communication is possible is limited due to the movement of the mobile device, and therefore it is sometimes required to ensure line of sight (LOS) between the mobile communication device and the fixed communication device. For example, a method has been proposed for determining a driving condition of the mobile device to ensure line of sight when it is determined that line of sight between the mobile communication device and the fixed communication device is not ensured (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2021-158473

[0004] However, the above-mentioned conventional technology does not take into account the line of sight between the ranging devices used to position the terminal, which could lead to a decrease in the accuracy of positioning the terminal based on ranging between the ranging device and the terminal.

[0005] This technology was developed in light of these circumstances, and aims to suppress a decrease in the positioning accuracy of a terminal based on distance measurements between multiple distance measuring devices and the terminal.

[0006] The present technology has been made to solve the above-mentioned problems, and a first aspect thereof is a positioning system including a terminal capable of wireless communication, a plurality of ranging devices that measure distances to the terminal based on wireless communication with the terminal, and a positioning server that performs positioning of the terminal based on ranging results between the terminal and the ranging devices selected based on line of sight between the ranging devices. This brings about an effect of improving the positioning accuracy of the terminal while easing restrictions on the installation locations of the ranging devices.

[0007] In addition, in the first aspect, the distance measuring device may include a wireless communication circuit for wirelessly communicating with the terminal, a distance measuring circuit for measuring the distance to the terminal based on the wireless communication result with the terminal, and a sensor for detecting line of sight between the distance measuring devices, thereby providing an effect that the distance measuring device used for positioning the terminal is selected based on line of sight between the distance measuring devices.

[0008] In addition, in the first aspect, the distance measuring device may include an evaluation circuit that evaluates the reliability of the distance measurement result obtained by the distance measurement circuit, thereby providing an effect that distance measurement results used for positioning of the terminal are selected.

[0009] In the first aspect, the sensor may include a camera, a light detection and ranging (LiDAR), an optical communication device, or a laser transmitting and receiving device. This brings about an effect that line of sight between the ranging devices is detected.

[0010] In the first aspect, the sensor may detect the surrounding environment of the distance measuring device, thereby providing an effect that the distance measurement result of the distance measuring device is selected based on the surrounding environment of the distance measuring device.

[0011] In addition, in the first aspect, the positioning server may include a selection circuit that selects a ranging device to be used for positioning the terminal based on line of sight between the ranging devices, thereby reducing degradation of positioning accuracy caused by obstacles between the ranging devices.

[0012] In the first aspect, the distance measuring devices may perform relative positioning between the distance measuring devices based on wireless communication between the distance measuring devices, thereby providing an effect of enabling positioning of the terminal while responding to movement of the distance measuring devices.

[0013] In the first aspect, the distance measuring device may include an inertial measurement unit (IMU), thereby providing an effect that movement of the distance measuring device is detected.

[0014] A second aspect of the present invention is a distance measuring device including a wireless communication circuit for performing wireless communication, a distance measuring circuit for measuring the distance to a terminal based on the wireless communication result with the terminal, and a sensor for detecting the line of sight of the wireless communication, thereby improving the positioning accuracy of the terminal while easing restrictions on the installation location of the distance measuring device.

[0015] In the second aspect, the distance measuring circuit may measure the distance between the distance measuring devices based on the results of wireless communication with other distance measuring devices, thereby providing an effect of measuring not only the distance between the distance measuring device and the terminal but also the distance between the distance measuring devices.

[0016] In the second aspect, the sensor may include a camera, a LiDAR, an optical communication device, or a laser transmitting and receiving device. This brings about an effect that line of sight between the ranging devices is detected.

[0017] In the second aspect, the distance measuring device may further include an evaluation circuit that evaluates the reliability of the distance measurement result obtained by the distance measuring circuit, thereby providing an effect of selecting the distance measurement result to be used for positioning the terminal.

[0018] In the second aspect, the device may further include a communication circuit that notifies the terminal of the results of distance measurement by the distance measurement circuit, the visibility of the wireless communication, and the reliability of the results of distance measurement, thereby improving the positioning accuracy of the terminal while easing restrictions on the installation location of the distance measurement device.

[0019] In the second aspect, the distance measuring device may include an IMU, which provides an effect of detecting movement of the distance measuring device.

[0020] A third aspect is a positioning device including a communication device that performs communication, and a selection circuit that selects a plurality of ranging circuits to be used for positioning the terminal based on line-of-sight between ranging circuits that measure the distance to the terminal, thereby providing an effect that a ranging device to be used for positioning the terminal is selected based on line-of-sight between the ranging devices.

[0021] In the third aspect, the present invention may further include a positioning circuit that performs positioning of the terminal based on the distances to the terminal measured by each of the plurality of ranging devices selected by the selection circuit, thereby improving the accuracy of positioning the terminal while easing restrictions on the installation locations of the ranging devices.

[0022] In addition, in the third aspect, the positioning circuit may perform relative positioning of the ranging devices based on the distance between the ranging devices, thereby providing an effect of enabling positioning of the terminal while responding to movement of the ranging devices.

[0023] In the third aspect, the distance measuring device may include an IMU, thereby providing an effect that movement of the distance measuring device is detected.

[0024] 1 is a block diagram showing an example of the functional configuration of a positioning system according to a first embodiment. FIG. 2 is a block diagram showing an example of the arrangement of a terminal and a ranging device in the positioning system according to the first embodiment. FIG. 3 is a block diagram showing an example of the arrangement of obstacles between ranging devices in the positioning system according to the first embodiment. FIG. 4 is a block diagram showing an example of multipath between ranging devices according to the first embodiment. FIG. 5 is a diagram showing an example of the reliability of ranging and the presence or absence of line of sight between ranging devices according to the first embodiment. FIG. 6 is a diagram showing a positioning processing sequence of the positioning system according to the first embodiment. FIG. 7 is a flowchart showing an example of ranging operation according to the first embodiment. FIG. 8 is a flowchart showing an example of positioning operation according to the first embodiment. FIG. 9 is a diagram showing a specific example of a ranging sequence according to the first embodiment. FIG. 10 is a block diagram showing a specific example of a ranging device according to the first embodiment. FIG. 11 is a diagram showing an example of a format of a transmission signal according to the first embodiment. FIG. 12 is a diagram showing an example of autocorrelation characteristics of a correlation sequence according to the first embodiment. FIG. 13 is a block diagram showing an example of the hardware configuration of a ranging device according to the first embodiment. FIG. 14 is a block diagram showing an example of the hardware configuration of a positioning server according to the first embodiment. FIG. 15 is a block diagram showing an example of the functional configuration of a ranging device according to a second embodiment. FIG. 16 is a block diagram showing a modified example of the arrangement of ranging devices in the positioning system according to the second embodiment. FIG. 17 is a block diagram showing an example of the functional configuration of a ranging device according to a third embodiment. FIG. 11 is a diagram illustrating a positioning process sequence of a positioning system according to a third embodiment.

[0025] Hereinafter, modes for implementing the present technology (hereinafter referred to as embodiments) will be described. The description will be given in the following order: 1. First embodiment (an example in which a positioning server measures the position of a terminal based on the reliability of ranging evaluated by a ranging device) 2. Second embodiment (an example in which a relative distance between ranging devices is measured based on the movement of the ranging devices) 3. Third embodiment (an example in which a positioning server measures the position of a terminal based on the ranging results of a ranging device selected based on line of sight between the ranging devices and the reliability of the results)

[0026] 1. First Embodiment FIG. 1 is a block diagram showing an example of the functional configuration of a positioning system according to a first embodiment.

[0027] In the figure, the positioning system includes a positioning server 101, ranging devices 111, 121, 131, and the like, and a terminal 161. The positioning server 101 can be connected to the ranging devices 111, 121, 131, and the like via a network 106. The network 106 may be a wide area network (WAN) such as the Internet, a local area network (LAN) such as Wi-Fi or Ethernet (registered trademark), or a combination of a WAN and a LAN. The network 106 may also include a cellular network.

[0028] The positioning server 101 performs positioning of the terminal 161 based on the results of ranging between the terminal 161 and each of the ranging devices 111, 121, 131, etc., selected based on the line of sight between the ranging devices 111, 121, 131, etc. The positioning server 101 includes a positioning circuit 102, a selection circuit 103, and a communication circuit 104. In this case, the positioning server 101 can perform positioning by appropriately combining the relative distance, the time difference of arrival (TDOA), and the angle of arrival (AoA) between the terminal 161 and each of the ranging devices 111, 121, 131, etc.

[0029] The positioning circuit 102 acquires the distance measurement results between each of the distance measuring devices 111, 121, 131, ... and the terminal 161 via the communication circuit 104. Then, the positioning circuit 102 performs positioning of the terminal 161 based on the distance measurement results between each of the distance measuring devices 111, 121, 131, ... and the terminal 161. When locating the terminal 161, the positioning circuit 102 can refer to the distance measurement results between the distance measuring devices 111, 121, 131, ... and the terminal 161 selected by the selection circuit 103. Furthermore, the positioning circuit 102 can select the positioning results between each of the distance measuring devices 111, 121, 131, ... and the terminal 161 to be used for locating the terminal 161 based on the reliability of the distance measurement results of each of the distance measuring devices 111, 121, 131, ...

[0030] The selection circuit 103 acquires line-of-sight information between the distance measuring devices 111, 121, 131, etc. via the communication circuit 104. Then, based on the line-of-sight information between the distance measuring devices 111, 121, 131, etc., the selection circuit 103 selects the distance measuring devices 111, 121, 131, etc. to be used for positioning the terminal 161 and notifies the positioning circuit 102. For example, the selection circuit 103 can select a combination of distance measuring devices 111, 121, 131, etc. that have mutual line-of-sight and notify the positioning circuit 102 of the combination. If the selection circuit 103 cannot select a combination of distance measuring devices 111, 121, 131, etc. that have mutual line-of-sight, it may sound an alarm. This makes it easier to determine whether positioning is possible and whether the distance measuring devices 111, 121, 131, etc. should be re-installed.

[0031] The communication circuit 104 communicates with each of the distance measuring devices 111, 121, 131, etc. via the network 106. The communication circuit 104 then notifies the selection circuit 103 of line-of-sight information between the distance measuring devices 111, 121, 131, etc. The communication circuit 104 also notifies the positioning circuit 102 of the distance measurement results and their reliability between each of the distance measuring devices 111, 121, 131, etc. and the terminal 161.

[0032] Each of the distance measuring devices 111, 121, 131, etc. measures the distance to the terminal 161 based on wireless communication with the terminal 161. The distance measuring devices 111, 121, 131, etc. can be distributed and installed in shopping malls, theme parks, airport terminals, train stations, underground shopping malls, parks, etc.

[0033] Each of the distance measuring devices 111, 121, 131 includes a distance measuring circuit 112, 122, 132, a sensor 113, 123, 133, a wireless communication circuit 114, 124, 134, a communication circuit 118, 128, 138, and an evaluation circuit 119, 129, 139. Each of the wireless communication circuits 114, 124, 134 includes a transmitting circuit 115, 125, 135 and a receiving circuit 116, 126, 136. Each of the transmitting circuits 115, 125, 135 and each of the receiving circuits 116, 126, 136 are connected to an antenna 117, 127, 137, respectively.

[0034] Each ranging circuit 112, 122, 132... communicates with terminal 161 via each wireless communication circuit 114, 124, 134.... Then, each ranging circuit 112, 122, 132... measures the distance to terminal 161 based on the results of wireless communication with terminal 161. In measuring the distance to terminal 161, each ranging circuit 112, 122, 132... may use, for example, a single-sided, two-way ranging (SS-TWR) method or a double-sided, two-way ranging (DS-TWR) method.

[0035] Furthermore, the distance measurement circuits 112, 122, 132... can communicate with the distance measurement devices 111, 121, 131... via the wireless communication circuits 114, 124, 134.... The distance measurement circuits 112, 122, 132... can measure the distance between the distance measurement devices 111, 121, 131... based on the results of wireless communication between the distance measurement devices 111, 121, 131....

[0036] Each sensor 113, 123, 133... detects the line of sight (JB) between the ranging devices 111, 121, 131.... Each sensor 113, 123, 133... can also detect the surrounding environment of the ranging devices 111, 121, 131.... This surrounding environment may include, for example, the presence or absence of multipath. The surrounding environment of the ranging devices 111, 121, 131... may also include, for example, the presence or absence of reflective surfaces (floors, walls, ceilings, etc.) or glass surfaces (windows or showcases) around the ranging devices 111, 121, 131.... Each sensor 113, 123, 133... may include a camera, a light detection and ranging (LiDAR), an optical communication device, or a laser transmitting and receiving device.

[0037] The presence or absence of a line-of-sight propagation path can be detected by using a camera to capture an image of another distance measuring device or a specific marker such as a QR code (registered trademark). Alternatively, by attaching a blinking LED or the like to each distance measuring device 111, 121, 131, etc. and making it emit light in a predetermined pattern, it is possible to identify the distance measuring device 111, 121, 131, etc. and detect the presence or absence of a line-of-sight propagation path.

[0038] LiDAR scans a certain area to generate a point cloud of surrounding objects. The shape of each ranging device 111, 121, 131, etc. can be identified from the point cloud, and the presence or absence of a line-of-sight propagation path can be detected. In the case of laser light or LiDAR, the presence or absence of a line-of-sight propagation path can be more reliably detected by using a retroreflective reflector in each ranging device 111, 121, 131, etc.

[0039] In optical communications, signal propagation characteristics are highly linear, and communication is possible only between distance measuring devices that are in a line-of-sight relationship, so it can be used to determine whether or not there is a line-of-sight propagation path.

[0040] When measuring the relative positions between ranging devices, in addition to a positioning method using radio ranging, a GNSS (Global Navigation Satellite System) positioning system, ranging sensors such as LiDAR, cameras, and radar, or ranging using optical communication may also be used in combination.

[0041] Each of the wireless communication circuits 114, 124, 134... performs wireless communication JC between the distance measuring devices 111, 121, 131.... Furthermore, each of the wireless communication circuits 114, 124, 134... performs wireless communication JA1 to JA3... with the terminal 161. For the wireless communication JA1 to JA3... and JC, UWB (Ultra Wide Band) communication may be used. UWB communication transmits and receives short pulses of about 2 ns, making it possible to estimate the signal propagation time on the order of ns, i.e., the distance, with an accuracy on the order of centimeters.

[0042] At this time, each of the transmission circuits 115, 125, 135, etc. can transmit data used to measure the relative distance between the distance measuring devices 111, 121, 131, etc. Also, each of the transmission circuits 115, 125, 135, etc. can transmit data used to measure the distance to the terminal 161.

[0043] Each of the receiving circuits 116, 126, 136, etc. can receive data used to measure the relative distance between the distance measuring devices 111, 121, 131, etc. Also, each of the receiving circuits 116, 126, 136, etc. can receive data used to measure the distance to the terminal 161.

[0044] Each of the communication circuits 118, 128, 138, etc. communicates with the positioning server 101 via the network 106. Each of the communication circuits 118, 128, 138, etc. notifies the positioning server 101 of line-of-sight information between the ranging devices 111, 121, 131, etc. Furthermore, each of the communication circuits 118, 128, 138, etc. notifies the positioning server 101 of the results of ranging between the ranging devices 111, 121, 131, etc. and the terminal 161 and their reliability.

[0045] The evaluation circuits 119, 129, 139... determine whether there is line of sight between the distance measuring devices 111, 121, 131.... At this time, if the distance measuring devices 111, 121, 131... of the other party can be confirmed within the angle of view of the camera, each evaluation circuit 119, 129, 139... can determine that there is line of sight between the distance measuring devices 111, 121, 131.... On the other hand, if the distance measuring devices 111, 121, 131... of the other party cannot be confirmed within the angle of view of the camera, each evaluation circuit 119, 129, 139... may determine that there is no line of sight between the distance measuring devices 111, 121, 131....

[0046] The evaluation circuits 119, 129, 139... evaluate the reliability of the ranging results between the respective ranging devices 111, 121, 131... and the terminal 161 based on the surrounding environment of the ranging devices 111, 121, 131... and the quality of the communication data used for ranging. For example, the evaluation circuits 119, 129, 139... may assign H (high), M (medium), or L (low) to the ranging results as an index of reliability based on the signal strength of the wireless communication.

[0047] The terminal 161 is capable of wireless communication with each of the distance measuring devices 111, 121, 131, etc. The terminal 161 may be a tag, an IC card, a mobile terminal such as a smartphone, etc. The terminal 161 may also be embedded in a key, a wristwatch, a wallet, a bag, etc.

[0048] The terminal 161 includes a wireless communication circuit 164 and an antenna 167. The wireless communication circuit 164 includes a transmitting circuit 165 and a receiving circuit 166. The transmitting circuit 165 and the receiving circuit 166 are connected to the antenna 167.

[0049] The wireless communication circuit 164 performs wireless communications JA1 to JA3, etc. with each of the wireless communication circuits 114, 124, 134, etc. At this time, the transmitting circuit 165 can transmit data used to measure the distance between each of the wireless communication circuits 114, 124, 134, etc. The receiving circuit 166 can receive data used to measure the distance between each of the wireless communication circuits 114, 124, 134, etc.

[0050] FIG. 2 is a block diagram showing an example of the arrangement of terminals and distance measuring devices in the positioning system according to the first embodiment.

[0051] In the figure, for example, distance measuring devices 111, 121, 131, 141, and 151 are installed indoors. The distance measuring devices 111, 121, 131, 141, and 151 can be fixed to, for example, the ceiling of the indoor space. A person carrying a terminal 161 is moving around the indoor space.

[0052] At this time, to perform positioning of terminal 161, each of ranging devices 111, 121, 131, 141, and 151 measures distances D1 to D5 to terminal 161. Then, assuming that the distances between ranging devices 111, 121, 131, 141, and 151 are known, positioning server 101 can perform positioning of terminal 161 by selecting at least three of distances D1 to D5 to terminal 161. For example, to perform positioning of terminal 161, positioning server 101 can select ranging devices 111, 121, and 131 and use distances D1 to D3 to terminal 161.

[0053] FIG. 3 is a block diagram showing an example of the arrangement of obstacles between distance measuring devices in the positioning system according to the first embodiment.

[0054] In the figure, for example, assume that there is an obstacle 170 between the ranging devices 111 and 131. The obstacle 170 may be a fixed object such as a pillar or a movable object such as an advertising tower. In this case, when the positioning server 101 receives the line-of-sight detection results between the ranging devices 111 and 131 from each ranging device 111 and 131, it can determine that there is no line-of-sight between the ranging devices 111 and 131. Then, to perform positioning of the terminal 161, the positioning server 101 can select three of the ranging devices 111, 121, 131, 141, and 151 so as not to include the combination of the ranging devices 111 and 131. For example, to perform positioning of the terminal 161, the positioning server 101 can select the ranging devices 111, 121, and 141 and use the distances D1, D2, and D4 to the terminal 161.

[0055] FIG. 4 is a block diagram showing an example of multipath between distance measuring devices according to the first embodiment.

[0056] In the figure, it is assumed that there is a floor surface MF below the ranging devices 111 and 141. In this case, an output wave LI emitted from the ranging device 111 is reflected by the floor surface MF, and a reflected wave LF is incident on the ranging device 141, resulting in a multipath wave. When this multipath wave occurs, it takes time to detect the reflected wave LF, and the relative distance between the ranging devices 111 and 141 is measured to be longer than it actually is. For this reason, when the positioning server 101 performs positioning including the combination of the ranging devices 111 and 141, the positioning accuracy decreases.

[0057] At this time, each ranging device 111, 141 can detect the surrounding environment of each ranging device 111, 141. Then, each ranging device 111, 141 can evaluate the reliability of the ranging result based on the surrounding environment of each ranging device 111, 141, and notify the ranging result and its reliability to the positioning server 101. Then, the positioning server 101 can select the ranging results of each ranging device 111, 141 based on the reliability of the ranging results of each ranging device 111, 141, and perform positioning of the terminal 161 based on the selected ranging results.

[0058] FIG. 5 is a diagram illustrating an example of the reliability of distance measurement and the presence or absence of line of sight between distance measurement devices according to the first embodiment.

[0059] In the figure, the positioning server 101 can create a reliability table TB1 based on the reliability of the distance measurement results obtained by each of the distance measuring devices 111, 121, 131, .... At this time, the positioning server 101 can assign a distance measuring device ID to each of the distance measuring devices 111, 121, 131, 141, and 151. In the reliability table TB1, the distance measurement results and their reliability of each of the distance measuring devices 111, 121, 131, 141, and 151 are registered for each distance measuring device ID.

[0060] In the figure, at b, the positioning server 101 can create a line-of-sight table TB2 based on line-of-sight information between the ranging devices 111, 121, 131, etc. The line-of-sight table TB2 registers the relative positions of the ranging devices 111, 121, 131, 141, and 151 for each ranging device ID. The line-of-sight table TB2 also registers whether or not there is line-of-sight for each combination of the ranging devices 111, 121, 131, 141, and 151. In the line-of-sight table TB2, 1 may be assigned to indicate line-of-sight and 0 to indicate no line-of-sight.

[0061] FIG. 6 is a diagram showing a positioning process sequence of the positioning system according to the first embodiment.

[0062] In the figure, the distance measuring device 111 transmits line-of-sight information for wireless communication of the distance measuring device 111 to the positioning server 101 (M1). At this time, the positioning server 101 records the line-of-sight information for wireless communication of the distance measuring device 111.

[0063] Next, the distance measuring device 121 transmits line-of-sight information for wireless communication of the distance measuring device 121 to the positioning server 101 (M2). At this time, the positioning server 101 records the line-of-sight information for wireless communication of the distance measuring device 121.

[0064] Similarly, the other distance measuring devices 131 , 141 , and 151 can also transmit wireless communication line-of-sight information to the positioning server 101 .

[0065] Next, the positioning server 101 creates (S0) a line-of-sight table based on line-of-sight information of wireless communication between the distance measuring devices 111, 121, 131, 141, and 151. This line-of-sight table is, for example, line-of-sight table TB2 in FIG.

[0066] Next, the terminal 161 transmits a Poll message to the ranging device 111 (K1), and the ranging device 111 receives the Poll message. At this time, the terminal 161 records the transmission time Tpt of the Poll message, and the ranging device 111 records the reception time Tpr of the Poll message.

[0067] Next, the distance measuring device 111 transmits a Response message to the terminal 161 (K2), and the terminal 161 receives the Response message. At this time, the distance measuring device 111 records the transmission time Trt of the Response message, and the terminal 161 records the reception time Trr of the Response message.

[0068] Next, the terminal 161 transmits a Final message to the ranging device 111 (K3), and the ranging device 111 receives the Final message. At this time, the terminal 161 records the transmission time Tpt of the Poll message, the reception time Trr of the Response message, and the transmission time Tft of the Final message in the Final message. The transmission time Tft of the Final message can be determined in advance. The ranging device 111 receives the transmission time Tpt of the Poll message, the reception time Trr of the Response message, and the transmission time Tft of the Final message, and records the reception time Tfr of the Final message. The ranging device 111 also measures the received signal strength of the Final message.

[0069] Next, the ranging device 111 calculates the time using the Poll message transmission time Tpt, the Poll message reception time Tpr, the Response message transmission time Trt, the Response message reception time Trr, the Final message transmission time Tft, and the Final message reception time Tfr, and calculates the distance between the ranging device 111 and the terminal 161. The ranging device 111 also creates reliability indicators H, M, and L from the received signal strength of the Final message (S1). Then, the ranging device 111 reports the ranging result and reliability information to the positioning server 101 using a distance message (K4).

[0070] Similarly, the terminal 161 transmits a Poll message to the ranging device 121 (K5), and the ranging device 121 receives the Poll message. At this time, the terminal 161 records the transmission time Tpt of the Poll message, and the ranging device 111 records the reception time Tpr of the Poll message.

[0071] Next, the distance measuring device 121 transmits a Response message to the terminal 161 (K6), and the terminal 161 receives the Response message. At this time, the distance measuring device 121 records the transmission time Trt of the Response message, and the terminal 161 records the reception time Trr of the Response message.

[0072] Next, the terminal 161 transmits a Final message to the ranging device 121 (K7), and the ranging device 121 receives the Final message. At this time, the terminal 161 records the transmission time Tpt of the Poll message, the reception time Trr of the Response message, and the transmission time Tft of the Final message in the Final message. The ranging device 121 receives the transmission time Tpt of the Poll message, the reception time Trr of the Response message, and the transmission time Tft of the Final message, and records the reception time Tfr of the Final message. The ranging device 121 also measures the received signal strength of the Final message.

[0073] Next, the ranging device 121 calculates the time using the Poll message transmission time Tpt, the Poll message reception time Tpr, the Response message transmission time Trt, the Response message reception time Trr, the Final message transmission time Tft, and the Final message reception time Tfr, and calculates the distance between the ranging device 121 and the terminal 161. The ranging device 121 also creates reliability indicators H, M, and L from the received signal strength of the Final message (S2). Then, the ranging device 121 reports the ranging result and reliability information to the positioning server 101 using a distance message (K8).

[0074] The other distance measuring devices 131, 141, and 151 can be processed in a similar manner.

[0075] Next, the positioning server 101 performs positioning calculations for the terminal 161 based on the ranging results reported from the ranging devices 111, 121, 131, 141, and 151 (S3). At this time, the positioning server 101 selects the ranging devices 111, 121, 131, 141, and 151 to use in the positioning calculations for the terminal 161 based on line-of-sight information between the ranging devices 111, 121, 131, 141, and 151. The positioning server 101 also selects the ranging results of the ranging devices 111, 121, 131, 141, and 151 based on reliability information of the ranging results of the ranging devices 111, 121, 131, 141, and 151.

[0076] Next, the positioning server 101 reports the positioning result of the terminal 161 to the distance measuring device 111 using a position message (K9).

[0077] Next, the distance measuring device 111 uses a report message to report the positioning result of the terminal 161 to the terminal 161 (K10).

[0078] In the above example, it is assumed that the distance measuring device 111 receives a Poll message from the terminal 161 first, but it may be determined in other ways.

[0079] 7 and 8 are flowcharts showing an example of a positioning operation according to the first embodiment.

[0080] 7, the distance measuring devices 111, 121, 131, etc. measure the distances between themselves based on wireless communication (S101). Then, the distance measuring devices 111, 121, 131, etc. notify the positioning server 101 of the measurement results of the distances between themselves. Note that if the distances between the distance measuring devices 111, 121, 131, etc. are set in advance, this process may be omitted.

[0081] Next, based on the sensing operation, each of the ranging devices 111, 121, 131, etc. determines whether there is line of sight between them (S102). Then, each of the ranging devices 111, 121, 131, etc. notifies the positioning server 101 of the determination result of whether there is line of sight between them.

[0082] Next, the positioning server 101 records the measurement results of the distances between the distance measuring devices 111, 121, 131, . . . notified by each of the distance measuring devices 111, 121, 131, . . . and the determination results of whether there is line of sight between the distance measuring devices 111, 121, 131, .

[0083] Next, the positioning server 101 calculates the relative positions of the distance measuring devices 111, 121, 131, . . . based on the measurement results of the distances between the distance measuring devices 111, 121, 131, .

[0084] 8, the positioning server 101 selects a ranging device 111, 121, 131, etc. to be used for positioning the terminal 161 based on the results of the determination of the presence or absence of line of sight between the ranging devices 111, 121, 131, etc. notified by each ranging device 111, 121, 131, etc. (S111). Then, the positioning server 101 notifies the selected ranging device 111, 121, 131, etc. to measure the distance to the terminal 161.

[0085] Next, the distance measuring devices 111, 121, 131, . . . selected by the positioning server 101 measure the distance to the terminal 161 (S112).

[0086] Next, the ranging devices 111, 121, 131, etc. selected by the positioning server 101 notify the positioning server 101 of the measurement results of the distances to the terminal 161. Then, the positioning server 101 records the measurement results of the distances to the terminal 161 notified by the ranging devices 111, 121, 131, etc. (S113).

[0087] Next, the positioning server 101 performs calculations to measure the position of the terminal 161 based on the results of measuring the distances between the distance measuring devices 111, 121, 131, . . . and the results of measuring the distances between the distance measuring devices 111, 121, 131, .

[0088] Next, the positioning server 101 outputs the positioning result of the terminal 161 (S115). At this time, the positioning server 101 may notify the terminal 161 of the positioning result of the terminal 161 via any one of the selected distance measuring devices 111, 121, 131, . . .

[0089] FIG. 9 is a diagram showing a specific example of a distance measurement sequence according to the first embodiment.

[0090] In FIG. 1A, in the SS-TWR method, one of the devices DA and DB uses bidirectional frame transmission over a wireless link to estimate the distance between the two devices DA and DB.

[0091] At this time, the time Tr from when device DA sends a message to device DB to when it receives the message from device DB and the time Ty from when device DB receives the message from device DA to when it sends the message back to device DA are measured. Then, the propagation time Tp between device DA and device DB is calculated, and the distance can be estimated from the propagation time Tp.

[0092] In FIG. 1b, in the DS-TWR scheme, both devices DA and DB use bidirectional frame transmission on the wireless link to estimate the distance between the two devices DA and DB.

[0093] At this time, the time Tr1 from when device DA sends a message to the device DB until it receives the message from the device DB, and the time Ty1 from when device DB receives the message from device DA and then sends the message back to device DA are measured. Also, the time Tr2 from when device DB sends a message to device DA until it receives the message from device DA, and the time Ty2 from when device DA receives the message from the device DB and then sends the message back to device DB are measured. At this time, the propagation time Tp between device DA and device DB can be given by the following equation:

[0094] Tp=(Tr1×Tr2−Ty1×Ty2) / (Tr1+Tr2+Ty1+Ty2)

[0095] However, Tr1=Trr-Tpt, Tr2=Trt-Tfr, Ty1=Trt-Tpr, and Ty2=Trr-Tft.

[0096] Here, the distance d can be given by d = c·Tp, where c is the speed of light.

[0097] 10 is a block diagram showing a specific example of the distance measuring device according to the first embodiment, in which the distance measurement is performed using the UWB system.

[0098] In this figure, a transmitter 201 and a receiver 211 can be provided in the wireless communication circuits 114, 124, 134, . . . , 164.

[0099] The transmitter 201 includes a transmission circuit 204. The transmission circuit 204 is connected to an antenna 205. The transmission circuit 204 receives as input a correlation sequence 202 and transmission data 203.

[0100] A transmission circuit 204 generates a transmission signal by combining the correlation sequence 202 and transmission data 203 , converts it into an RF (Radio Frequency) signal of a desired carrier frequency, and emits it as a radio wave from an antenna 205 .

[0101] Receiver 211 comprises a receiving circuit 214, a correlator 213 and a time-of-arrival detector 216. Receiving circuit 214 is connected to an antenna 215. Correlator 213 receives as input a correlation sequence 212. Correlation sequences 202, 212 are agreed upon between transmitter 201 and receiver 211.

[0102] The receiving circuit 214 receives the radio wave emitted from the transmitter 201 via the antenna 215 , converts it into a baseband signal, and inputs it to the correlator 213 .

[0103] The correlator 213 calculates the correlation between the baseband signal input from the receiving circuit 214 and the correlation sequence 212 , and inputs the correlation value to the arrival time detector 216 .

[0104] Arrival time detector 216 detects and outputs the time at which the correlation value input from correlator 213 reaches a peak as arrival time Tr. The arrival time Tr is obtained at the end of the correlation sequence in the format sequence of the transmission signal.

[0105] FIG. 11 is a diagram illustrating an example of a format of a transmission signal according to the first embodiment.

[0106] In this figure, a transmit signal can be generated by a correlation sequence 202 followed by transmit data 203 .

[0107] 12 is a diagram showing an example of autocorrelation characteristics of a correlation sequence according to the first embodiment, which shows the autocorrelation characteristics of a preamble code defined in IEEE802.15.4z-2020.

[0108] In FIG. 10A, indexes 1-8 (31 length) are shown as the autocorrelation characteristics of the correlation sequence.

[0109] In FIG. 11B, index 9-24 (length 127) is shown as the autocorrelation characteristic of the correlation sequence.

[0110] In FIG. 10c, index 25-32 (length 91) is shown as the autocorrelation characteristic of the correlation sequence.

[0111] 13 is a block diagram showing an example of the hardware configuration of a distance measuring device according to the first embodiment. Note that, in the figure, the hardware configuration of the distance measuring device 111 is taken as an example, but the hardware of the distance measuring devices 121, 131, etc. can also be configured in a similar manner.

[0112] In the figure, the ranging device 111 includes a processor 311, communication control devices 312 and 313, communication interfaces 316 and 317, a main memory unit 314, an auxiliary memory unit 315, and an input / output interface 318. The processor 311, communication control devices 312 and 313, communication interfaces 316 and 317, the main memory unit 314, the auxiliary memory unit 315, and the input / output interface 318 are connected to each other via an internal bus 319. The main memory unit 314 and the auxiliary memory unit 315 are accessible from the processor 311. The communication control device 312 is connected to the network 106 via the communication interface 316. The communication control device 313 is connected to the antenna 117 via the communication interface 317.

[0113] An input device 301 and an output device 302 are also connected to the distance measuring device 111. The input device 301 and the output device 302 are connected to an internal bus 319 via an input / output interface 318. The input device 301 is, for example, a sensor, a keyboard, a mouse, a touch panel, a card reader, or a microphone. The output device 302 is, for example, a screen display device (such as a liquid crystal monitor, an organic EL (Electro Luminescence) display, or a graphics card), a speaker, or a printer.

[0114] The processor 311 is hardware that performs overall control of the ranging device 111. For example, the processor 311 can cause the communication control devices 312 and 313, the main memory unit 314, and the auxiliary memory unit 315 to operate in cooperation with each other during ranging processing. The processor 311 may be a central processing unit (CPU) or a graphics processing unit (GPU). The processor 311 may be a single-core processor or a multi-core processor. The processor 311 may include a hardware circuit (for example, a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC)) such as an accelerator that performs part of the processing.

[0115] The main memory unit 314 may include, for example, a semiconductor memory such as a static random access memory (SRAM) or a dynamic random access memory (DRAM). The main memory unit 314 may store programs being executed by the processor 311 and may provide a work area for the processor 311 to execute programs.

[0116] The auxiliary storage unit 315 is a storage device with a large storage capacity, such as a flash memory or an SD card. The auxiliary storage unit 315 can hold executable files for various programs and data used to execute the programs. The auxiliary storage unit 315 can store a ranging processing program 315A. The ranging processing program 315A may be software that can be installed in the ranging device 111, or may be incorporated into the ranging device 111 as firmware.

[0117] The communication control device 312 is hardware having a function of controlling communication with the outside world. The communication control device 312 is connected to the network 106 via a communication interface 316.

[0118] The communication control device 313 is hardware having a function of controlling wireless communication with the outside world. The communication control device 313 is connected to the antenna 117 via a communication interface 317.

[0119] The input / output interface 318 converts data input from the input device 301 into a data format that can be processed by the processor 311 , and converts data output from the processor 311 into a data format that can be processed by the output device 302 .

[0120] The processor 311 can perform distance measurement processing by reading the distance measurement processing program 315A into the main memory unit 314 and executing the distance measurement processing program 315A. In this distance measurement processing, the processor 311 can calculate the distance to the terminal 161 based on wireless communication, determine the visibility of wireless communication based on the detection results of the sensor, and determine the reliability of the distance measurement results based on wireless communication.

[0121] The execution of the distance measurement processing program 315A may be shared among multiple processors or computers. Alternatively, the processor 311 may instruct a cloud computer or the like via the network 106 to execute all or part of the distance measurement processing program 315A and receive the execution results.

[0122] FIG. 14 is a block diagram illustrating an example of a hardware configuration of the positioning server according to the first embodiment.

[0123] 1, the positioning server 101 includes a processor 321, a communication control device 322, a communication interface 326, a main memory 324, an auxiliary memory 325, and an input / output interface 328. The processor 321, the communication control device 322, the communication interface 326, the main memory 324, the auxiliary memory 325, and the input / output interface 328 are connected to each other via an internal bus 329. The main memory 324 and the auxiliary memory 325 are accessible from the processor 321. The communication control device 322 is connected to the network 106 via the communication interface 326.

[0124] An input device 331 and an output device 332 are also connected to the positioning server 101. The input device 331 and the output device 332 are connected to an internal bus 329 via an input / output interface 328.

[0125] The processor 321 is hardware that performs overall control of the positioning server 101. For example, the processor 321 can cause the communication control device 322, the main storage unit 324, and the auxiliary storage unit 325 to operate in cooperation with each other in the positioning process.

[0126] The main memory unit 324 may include, for example, a semiconductor memory such as an SRAM or a DRAM. The main memory unit 324 may store programs being executed by the processor 321 and may provide a work area for the processor 321 to execute programs.

[0127] The auxiliary storage unit 325 is a storage device with a large storage capacity, such as a flash memory or an SD card. The auxiliary storage unit 325 can hold executable files for various programs and data used to execute the programs. The auxiliary storage unit 325 can store a positioning processing program 325A, a reliability table TB1, and a visibility table TB2. The positioning processing program 325A may be software that can be installed in the positioning server 101, or may be incorporated into the positioning server 101 as firmware.

[0128] The communication control device 322 is hardware having a function of controlling communication with the outside world. The communication control device 322 is connected to the network 106 via a communication interface 326.

[0129] The input / output interface 328 converts data input from the input device 331 into a data format that can be processed by the processor 321 , and converts data output from the processor 321 into a data format that can be processed by the output device 332 .

[0130] The processor 321 can perform positioning processing by reading the positioning processing program 325A into the main memory unit 314 and executing the positioning processing program 325A. In this positioning processing, the processor 321 can perform positioning of the terminal 161 based on the distance measurement results of each of the distance measurement devices 111, 121, 131, etc. At this time, the processor 321 can refer to the line-of-sight table TB2 and select the distance measurement device 111, 121, 131, etc. to be used for positioning the terminal 161. The processor 321 can also refer to the reliability table TB1 and select the distance measurement result of each of the distance measurement devices 111, 121, 131, etc.

[0131] The execution of the positioning processing program 325A may be shared among multiple processors or computers. Alternatively, the processor 321 may instruct a cloud computer or the like via the network 106 to execute all or part of the positioning processing program 325A and receive the execution results.

[0132] As described above, in the first embodiment, the positioning server 101 performs positioning of the terminal 161 based on the distance measurement results of the distance measurement devices 111, 121, 131... selected based on the line of sight between the distance measurement devices 111, 121, 131... and the reliability of the distance measurement results evaluated by each distance measurement device 111, 121, 131.... This eliminates the need to arrange each distance measurement device 111, 121, 131... so that communication can always be established between all of the distance measurement devices 111, 121, 131.... This reduces restrictions on the installation location of each distance measurement device 111, 121, 131... while improving the positioning accuracy of the terminal 161. This avoids the need for surveying and construction work when installing the distance measurement devices 111, 121, 131..., thereby reducing installation time and costs.

[0133] 2. Second Embodiment In the above-described first embodiment, the positioning server 101 performed positioning of the terminal 161 based on the distance measurement results of the distance measurement devices 111, 121, 131, etc., selected based on the line of sight between the distance measurement devices 111, 121, 131, etc. In this second embodiment, the relative distances between the distance measurement devices are measured based on the movement of the distance measurement devices, and the distance measurement results are notified to the positioning server 101.

[0134] FIG. 15 is a block diagram showing an example of the functional configuration of a distance measuring device according to the second embodiment, and FIG. 16 is a block diagram showing a modified example of the arrangement of the distance measuring device in the positioning system according to the second embodiment.

[0135] 15, a distance measuring device 511 is obtained by adding a determination circuit 512 and a sensor 513 to the distance measuring device 111 of the first embodiment described above. The other configuration of the distance measuring device 511 of the second embodiment is the same as the configuration of the distance measuring device 111 of the first embodiment described above.

[0136] In this case, instead of the ranging device 111 of the positioning system in Fig. 3, a ranging device 511 may be provided as shown in Fig. 16. In this case, the ranging device 511 may be installed indoors so that it is movable. For example, the ranging device 511 may be installed indoors without being fixed with screws or the like, or may be mounted on a drone or a self-propelled robot.

[0137] The distance measuring device 511 measures the relative distance between the distance measuring device 511 and each of the distance measuring devices 121 , 131 , 141 , and 151 based on the detection result of the movement of the distance measuring device 511 , and notifies the positioning server 101 of the distance measurement result.

[0138] The sensor 513 detects the movement of the distance measuring device 511. The sensor 513 may be an IMU (Inertial Measurement Unit) such as an acceleration sensor or a gyro sensor.

[0139] The determination circuit 512 determines whether the distance measuring device 511 has moved or not based on the detection result of the sensor 513. If the determination circuit 512 determines that the distance measuring device 511 has moved, it instructs the distance measuring circuit 112 to measure the relative distance between the distance measuring devices 121, 131, 141, and 151.

[0140] At this time, the distance measurement circuit 112 measures the relative distances between the distance measurement devices 121, 131, 141, and 151 based on wireless communication with the distance measurement devices 121, 131, 141, and 151. The distance measurement circuit 112 then notifies the positioning server 101 of the distance measurement results between the distance measurement devices 121, 131, 141, and 151.

[0141] The positioning server 101 can then perform relative positioning of each of the distance measuring devices 121 , 131 , 141 , 151 , and 513 based on the distance measurement results between the distance measuring device 511 and each of the distance measuring devices 121 , 131 , 141 , and 151 .

[0142] Furthermore, when the determination circuit 512 determines that the ranging device 511 has moved, it may instruct the sensor 113 to detect the line of sight between the ranging device 511 and each of the ranging devices 121, 131, 141, and 151. At this time, the sensor 113 detects the line of sight between the ranging device 511 and each of the ranging devices 121, 131, 141, and 151, and notifies the positioning server 101 of the detection result.

[0143] Then, the positioning server 101 can update the line-of-sight table TB2 in FIG. 5b based on the line-of-sight between the distance measuring device 511 and each of the distance measuring devices 121, 131, 141, and 151.

[0144] As described above, in the second embodiment, the relative distances between the ranging device 511 and each of the ranging devices 121, 131, 141, and 151 are measured based on the movement of the ranging device 511, and the results of the distance measurement are notified to the positioning server 101. This makes it possible to improve the positioning accuracy of the terminal 161 while responding to the movement of the ranging device 511.

[0145] 3. Third Embodiment In the above-described first embodiment, the positioning server 101 performed positioning of the terminal 161 based on the ranging results of the ranging devices 111, 121, 131, etc. selected based on the line of sight between the ranging devices 111, 121, 131, etc. In this third embodiment, the positioning server determines the reliability of the ranging results of the ranging devices based on the line of sight between the ranging devices and the surrounding environment of the ranging devices, and performs positioning of the terminal 161 based on the determination result.

[0146] FIG. 17 is a block diagram showing an example of the functional configuration of a distance measuring device according to the third embodiment.

[0147] In the figure, the positioning system includes a positioning server 701 and distance measuring devices 711, 721, 731, etc., instead of the positioning server 101 and distance measuring devices 111, 121, 131, etc., of the first embodiment described above. The other configurations of the positioning system of the third embodiment are the same as those of the positioning system of the first embodiment described above.

[0148] The positioning server 701 determines the reliability of the distance measurement results of each of the distance measuring devices 711, 721, 731, ... based on the line of sight between the distance measuring devices 711, 721, 731, ... and the surrounding environment of each of the distance measuring devices 711, 721, 731, ..., and performs positioning of the terminal 161 based on the determination result. The positioning server 701 is obtained by adding an evaluation circuit 105 to the positioning server 101 of the first embodiment described above. Other configurations of the positioning server 701 of the third embodiment are similar to the configuration of the positioning server 101 of the first embodiment described above.

[0149] The evaluation circuit 105 evaluates the reliability of the ranging results of each ranging device 711, 721, 731... based on line-of-sight information between the ranging devices 711, 721, 731... and the surrounding environment of each ranging device 711, 721, 731.... The surrounding environment of each ranging device 711, 721, 731... may include, for example, the presence or absence of multipath. In this case, the positioning circuit 102 selects the ranging result of each ranging device 711, 721, 731... based on the reliability of the ranging result of each ranging device 711, 721, 731..., and can perform positioning of the terminal 161 based on the selected ranging result.

[0150] Here, the communication circuit 104 can receive line-of-sight information between the distance measuring devices 711, 721, 731, ... and peripheral information of each of the distance measuring devices 711, 721, 731, ... from each of the distance measuring devices 711, 721, 731, .... The communication circuit 104 can then notify the evaluation circuit 105 of the line-of-sight information between the distance measuring devices 711, 721, 731, ... and peripheral information of each of the distance measuring devices 711, 721, 731, ....

[0151] Each of the ranging devices 711, 721, 731... detects the line of sight of wireless communication and the surrounding environment, and notifies the positioning server 701 of the line of sight of wireless communication information and the surrounding information. Each of the ranging devices 711, 721, 731... is obtained by removing the evaluation circuits 119, 129, 139... from the ranging devices 111, 121, 131... of the first embodiment. The remaining configuration of each of the ranging devices 711, 721, 731... of the third embodiment is the same as the configuration of the ranging devices 111, 121, 131... of the first embodiment.

[0152] At this time, each of the sensors 113, 123, 133, etc. detects the line of sight of wireless communication and the surrounding environment, and notifies the positioning server 101 via the communication circuits 118, 128, 138, etc. Then, the positioning server 701 evaluates the reliability of the ranging results of each of the ranging devices 711, 721, 731, etc. based on the line of sight information of wireless communication and the surrounding information of each of the ranging devices 711, 721, 731, etc., and can perform positioning of the terminal 161 based on the evaluation result.

[0153] FIG. 18 is a diagram illustrating a positioning process sequence of the positioning system according to the third embodiment.

[0154] In the figure, the distance measuring device 711 transmits wireless communication line-of-sight information and peripheral information of the distance measuring device 711 to the positioning server 701 (M11). At this time, the positioning server 701 records the wireless communication line-of-sight information and peripheral information of the distance measuring device 711.

[0155] Next, the ranging device 721 transmits the wireless communication line-of-sight information and peripheral information of the ranging device 721 to the positioning server 701 (M12). At this time, the positioning server 701 records the wireless communication line-of-sight information and peripheral information of the ranging device 721.

[0156] Similarly, the other distance measuring devices 731 . . . can also transmit wireless communication line-of-sight information and peripheral information to the positioning server 701 .

[0157] Next, the positioning server 701 creates a line-of-sight table based on line-of-sight information for wireless communication between the ranging devices 711, 721, 731, etc. (S10A). The positioning server 701 also creates a reliability table based on peripheral information for wireless communication between the ranging devices 711, 721, 731, etc. (S10B).

[0158] Next, the terminal 161 transmits a Poll message to the distance measuring device 711 (K11), and the distance measuring device 711 receives the Poll message. At this time, the terminal 161 records the transmission time Tpt of the Poll message, and the distance measuring device 711 records the reception time Tpr of the Poll message.

[0159] Next, the distance measuring device 711 transmits a Response message to the terminal 161 (K12), and the terminal 161 receives the Response message. At this time, the distance measuring device 711 records the transmission time Trt of the Response message, and the terminal 161 records the reception time Trr of the Response message.

[0160] Next, the terminal 161 transmits a Final message to the ranging device 711 (K13), and the ranging device 711 receives the Final message. At this time, the terminal 161 records the transmission time Tpt of the Poll message, the reception time Trr of the Response message, and the transmission time Tft of the Final message in the Final message. The ranging device 711 receives the transmission time Tpt of the Poll message, the reception time Trr of the Response message, and the transmission time Tft of the Final message, and records the reception time Tfr of the Final message.

[0161] Next, the ranging device 711 calculates the time using the Poll message transmission time Tpt, the Poll message reception time Tpr, the Response message transmission time Trt, the Response message reception time Trr, the Final message transmission time Tft, and the Final message reception time Tfr, and calculates the distance between the ranging device 711 and the terminal 161 (S11).The ranging device 711 then reports the ranging result to the positioning server 101 using a distance message (K14).

[0162] Similarly, the terminal 161 transmits a Poll message to the distance measuring device 721 (K15), and the distance measuring device 721 receives the Poll message. At this time, the terminal 161 records the transmission time Tpt of the Poll message, and the distance measuring device 721 records the reception time Tpr of the Poll message.

[0163] Next, the distance measuring device 721 transmits a Response message to the terminal 161 (K16), and the terminal 161 receives the Response message. At this time, the distance measuring device 721 records the transmission time Trt of the Response message, and the terminal 161 records the reception time Trr of the Response message.

[0164] Next, the terminal 161 transmits a Final message to the ranging device 721 (K17), and the ranging device 721 receives the Final message. At this time, the terminal 161 records the transmission time Tpt of the Poll message, the reception time Trr of the Response message, and the transmission time Tft of the Final message in the Final message. The ranging device 721 receives the transmission time Tpt of the Poll message, the reception time Trr of the Response message, and the transmission time Tft of the Final message, and records the reception time Tfr of the Final message.

[0165] Next, the ranging device 721 calculates the time using the Poll message transmission time Tpt, the Poll message reception time Tpr, the Response message transmission time Trt, the Response message reception time Trr, the Final message transmission time Tft, and the Final message reception time Tfr, and calculates the distance between the ranging device 721 and the terminal 161 (S12).The ranging device 721 then reports the ranging result to the positioning server 101 using a distance message (K18).

[0166] The other distance measuring devices 131 can be processed in the same manner.

[0167] Next, the positioning server 701 performs positioning calculations for the terminal 161 based on the ranging results reported from the ranging devices 711, 721, 731, etc. (S13). At this time, the positioning server 701 selects a ranging device 711, 721, 731, etc. to be used in the positioning calculations for the terminal 161 based on line-of-sight information between the ranging devices 711, 721, 731, etc. The positioning server 701 also selects the ranging results of each ranging device 711, 721, 731, etc. based on reliability information of the ranging results of each ranging device 711, 721, 731, etc.

[0168] Next, the positioning server 701 reports the positioning result of the terminal 161 to the distance measuring device 711 using a position message (K19).

[0169] Next, the distance measuring device 711 reports the positioning result of the terminal 161 to the terminal 161 using a report message (K20).

[0170] As described above, in the third embodiment, the positioning server 701 determines the reliability of the ranging results of the ranging devices 711, 721, 731, ... based on the line of sight between the ranging devices 711, 721, 731, ... and the surrounding environment of the ranging devices 711, 721, 731, ..., and performs positioning of the terminal 161 based on the determination result. This eliminates the need for each ranging device 711, 721, 731, ... to evaluate the reliability of the ranging result. This makes it possible to improve the positioning accuracy of the terminal 161 while suppressing an increase in the load on each ranging device 711, 721, 731, ....

[0171] In the above embodiment, an example has been described in which the positioning server and the ranging devices are housed in separate housings, but they can also be housed in a single housing. It is also possible to provide a positioning server function to all ranging devices, and have the positioning server installed in one of the ranging devices perform positioning depending on the situation.

[0172] Note that the above-described embodiment shows an example for realizing the present technology, and the matters in the embodiment and the matters specifying the invention in the claims correspond to each other. Similarly, the matters specifying the invention in the claims and the matters in the embodiment of the present technology with the same title correspond to each other. However, the present technology is not limited to the embodiment, and can be realized by applying various modifications to the embodiment within the scope of the gist. Furthermore, the effects described in this specification are merely examples and are not limited, and other effects may also be present.

[0173] The present technology may also be configured as follows: (1) A positioning system comprising: a terminal capable of wireless communication; a plurality of ranging devices that measure distances to the terminal based on wireless communication with the terminal; and a positioning server that performs positioning of the terminal based on a ranging result between the terminal and a ranging device selected based on line-of-sight between the ranging devices. (2) The positioning system according to (1), wherein the ranging device comprises: a wireless communication circuit that performs wireless communication with the terminal; a ranging circuit that measures the distance to the terminal based on the result of wireless communication with the terminal; and a sensor that detects line-of-sight between the ranging devices. (3) The positioning system according to (2), wherein the ranging device comprises: an evaluation circuit that evaluates reliability of a ranging result by the ranging circuit. (4) The positioning system according to (2), wherein the sensor comprises a camera, a LiDAR (Light Detection and Ranging), an optical communication device, or a laser transmitting and receiving device. (5) The positioning system according to any of (2) to (4), wherein the sensor detects the surrounding environment of the ranging device. (6) The positioning system according to any one of (1) to (5), wherein the positioning server comprises: a selection circuit that selects a ranging device to be used for positioning the terminal based on line-of-sight between the ranging devices. (7) The positioning system according to any one of (1) to (6), wherein the ranging device performs relative positioning between the ranging devices based on wireless communication between the ranging devices. (8) The positioning system according to any one of (1) to (7), wherein the ranging device comprises an IMU (Inertial Measurement Unit). (9) A ranging device comprising: a wireless communication circuit that performs wireless communication; a ranging circuit that measures the distance to the terminal based on a result of wireless communication with the terminal; and a sensor that detects line-of-sight of the wireless communication. (10) The ranging device according to (9), wherein the ranging circuit measures the distance between the ranging devices based on a result of wireless communication with another ranging device. (11) The ranging device according to (9) or (10), wherein the sensor comprises a camera, LiDAR, optical communication device, or laser transmitting / receiving device. (12) The distance measuring device according to any one of (9) to (11) above, further comprising an evaluation circuit for evaluating the reliability of the distance measurement result obtained by the distance measuring circuit.(13) The ranging device according to (12), further comprising a communication circuit that notifies the ranging result by the ranging circuit, the line of sight of the wireless communication, and the reliability of the ranging result. (14) The positioning device according to any of (9) to (13), wherein the ranging device comprises an IMU. (15) A positioning device comprising: a communication device that performs communication; and a selection circuit that selects multiple ranging circuits to be used for positioning the terminal based on the line of sight between ranging circuits that measure the distance to the terminal. (16) The positioning device according to (15), further comprising a positioning circuit that performs positioning of the terminal based on the distances to the terminal measured by each of the multiple ranging devices selected by the selection circuit. (17) The positioning device according to (16), wherein the positioning circuit performs relative positioning of the ranging device based on the distance between the ranging devices. (18) The positioning device according to any of (15) to (17), wherein the ranging device comprises an IMU.

[0174] 101 Positioning server 102 Positioning circuit 103 Selection circuit 104, 118, 128, 138 Communication circuit 106 Network 111, 121, 131 Distance measuring device 112, 122, 132 Distance measuring circuit 113, 123, 133 Sensor 114, 124, 134, 164 Wireless communication circuit 115, 125, 135, 165 Transmission circuit 116, 126, 136, 166 Reception circuit 117, 127, 137, 167 Antenna 119, 129, 139 Evaluation circuit 161 Terminal

Claims

1. A positioning system comprising: a terminal capable of wireless communication; a plurality of ranging devices that measure the distance to the terminal based on wireless communication with the terminal; and a positioning server that performs positioning of the terminal based on the ranging results between the terminal and a ranging device selected based on line of sight between the ranging devices.

2. The positioning system of claim 1, wherein the ranging device comprises a wireless communication circuit that performs wireless communication with the terminal, a ranging circuit that measures the distance to the terminal based on the results of wireless communication with the terminal, and a sensor that detects line of sight between the ranging device and the terminal.

3. The positioning system according to claim 2, wherein the distance measuring device is provided with an evaluation circuit for evaluating the reliability of the distance measurement result obtained by the distance measuring circuit.

4. The positioning system according to claim 2, wherein the sensor comprises a camera, a LiDAR (Light Detection And Ranging), an optical communication device or a laser transmitting and receiving device.

5. The positioning system according to claim 2, wherein the sensor detects the surrounding environment of the ranging device.

6. The positioning system according to claim 1, wherein the positioning server comprises a selection circuit that selects a ranging device to be used for positioning the terminal based on line of sight between the ranging devices.

7. The positioning system according to claim 1, wherein the distance measuring devices perform relative positioning between the distance measuring devices based on wireless communication between the distance measuring devices.

8. The positioning system according to claim 1, wherein the distance measuring device comprises an IMU (Inertial Measurement Unit).

9. A distance measuring device comprising: a wireless communication circuit for performing wireless communication; a distance measuring circuit for measuring the distance to a terminal based on the results of wireless communication with the terminal; and a sensor for detecting the line of sight of the wireless communication.

10. The distance measuring device according to claim 9, wherein the distance measuring circuit measures the distance between the distance measuring devices based on the results of wireless communication with other distance measuring devices.

11. The distance measuring device according to claim 9, wherein the sensor comprises a camera, a LiDAR, an optical communication device or a laser transmitting / receiving device.

12. The distance measuring device according to claim 9, further comprising an evaluation circuit for evaluating the reliability of the distance measurement result obtained by said distance measuring circuit.

13. The distance measuring device according to claim 12, further comprising: a communication circuit for notifying the distance measurement result by said distance measuring circuit, the visibility of said wireless communication, and the reliability of said distance measurement result.

14. The positioning device of claim 9, wherein the ranging device comprises an IMU.

15. A positioning device comprising: a communications device for carrying out communications; and a selection circuit for selecting a plurality of ranging circuits to be used for positioning the terminal based on line of sight between ranging circuits that measure the distance to the terminal.

16. The positioning device according to claim 15, further comprising: a positioning circuit that performs positioning of the terminal based on the distances to the terminal measured by each of a plurality of distance measuring devices selected by the selection circuit.

17. The positioning device according to claim 16, wherein the positioning circuit performs relative positioning of the distance measuring devices based on the distance between the distance measuring devices.

18. The positioning device of claim 15, wherein the ranging device comprises an IMU.

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