Positioning system, positioning device, positioning method, and positioning program

Abstract

A positioning device (11) of a positioning system (1) has: an attitude estimation unit (40) for estimating a first attitude of a wireless terminal (10); a radio wave reception unit (50) for calculating a first arrival angle (θ, φ) of a radio wave from a radio wave anchor (20) and a first distance (l) from the radio wave anchor (20); a first position estimation unit (60) for estimating a first position (x1) by using the first arrival angle (θ, φ) and the first distance (l); a second position estimation unit (70) for estimating a second position (x2) by using another method; an attitude correction unit (80) for generating a second attitude from the first attitude by using a three-dimensional rotation matrix which equalizes a first relative vector representing the position of the radio wave anchor (20) viewed from the first position (x1) with a second relative vector representing the position of the radio wave anchor (20) viewed from the second position (x2); and an inertial navigation unit (90) for estimating the position of the wireless terminal (10) by using a relative movement vector (Δx) obtained by inertial navigation and the second position (x2).

Description

Positioning system, positioning device, positioning method, and positioning program

[0001] The present disclosure relates to a positioning system, a positioning device, a positioning method, and a positioning program that measure the position of a wireless terminal.

[0002] Patent Literature 1 proposes a device for measuring the position of a wireless terminal (target device) such as a mobile phone. This device estimates movement information including the movement distance and movement direction of the wireless terminal using sensor values ​​output from an acceleration sensor, a gyro sensor, a geomagnetic sensor, etc., and estimates the reliability of the movement information by referring to the sensor values. Furthermore, this device measures the absolute coordinates of the wireless terminal using GPS (Global Positioning System) signals, corrects the position of the wireless terminal calculated based on the movement information using the absolute coordinates, and corrects the movement trajectory of the wireless terminal for each predetermined number of steps using the reliability of the movement information.

[0003] Japanese Patent Application Laid-Open No. 2019-148586

[0004] In the above-mentioned conventional device, the position of the wireless terminal and the past trajectory are corrected when the absolute coordinates of the wireless terminal are acquired, but the attitude of the wireless terminal is not corrected. Therefore, if a strong external magnetic field is present in the area where the wireless terminal is placed or if a residual magnetic field is present in the electronic components inside the wireless terminal, an error is superimposed on the sensor value of the geomagnetic sensor, and an error around the direction of gravity is superimposed on the attitude of the wireless terminal, resulting in a problem of reduced accuracy in measuring the position of the wireless terminal.

[0005] An object of the present disclosure is to provide a positioning system, a positioning device, a positioning method, and a positioning program that can improve the accuracy of measuring the position of a wireless terminal.

[0006] A positioning system according to the present disclosure is a system for measuring a terminal position of a wireless terminal equipped with a sensor unit including an acceleration sensor, an angular velocity sensor, and a geomagnetic sensor, and includes: an attitude estimation unit that estimates a first attitude of the wireless terminal using sensor values ​​detected by the sensor unit; a radio wave receiving unit that calculates a first angle of arrival of a first radio wave and a first distance between the radio wave anchor and the wireless terminal based on a first radio wave transmitted from the radio wave anchor installed at a predetermined position; a first position estimation unit that estimates a first position of the wireless terminal using the first angle of arrival and the first distance; The radio terminal is characterized by having a second position estimation unit that estimates a second position of the radio terminal using a predetermined method that does not use the angle of arrival; an attitude correction unit that estimates a three-dimensional rotation matrix that equates a first relative vector viewing the position of the radio anchor from the first position with a second relative vector viewing the position of the radio anchor from the second position, and corrects the first attitude using the three-dimensional rotation matrix to generate a second attitude; and an inertial navigation unit that estimates the terminal position of the radio terminal using the second position and a relative movement vector of the radio terminal calculated by inertial navigation based on the second attitude.

[0007] A positioning device according to the present disclosure is a device for measuring the position of a wireless terminal equipped with a sensor unit including an acceleration sensor, an angular velocity sensor, and a geomagnetic sensor, and includes: an attitude estimation unit that estimates a first attitude of the wireless terminal using sensor values ​​detected by the sensor unit; a radio wave receiving unit that calculates a first angle of arrival of a first radio wave and a first distance between the radio wave anchor and the wireless terminal based on a first radio wave transmitted from the radio wave anchor installed at a predetermined position; a first position estimation unit that estimates a first position of the wireless terminal using the first angle of arrival and the first distance; a second position estimation unit that estimates a second position of the wireless terminal using a predetermined method that does not use degrees of freedom; an attitude correction unit that estimates a three-dimensional rotation matrix that equates a first relative vector viewing the position of the radio anchor from the first position with a second relative vector viewing the position of the radio anchor from the second position, and corrects the first attitude using the three-dimensional rotation matrix to generate a second attitude; and an inertial navigation unit that estimates the terminal position of the wireless terminal using the second position and a relative movement vector of the wireless terminal calculated by inertial navigation based on the second attitude.

[0008] The positioning method disclosed herein is a method implemented by a positioning system that measures the position of a wireless terminal equipped with a sensor unit including an acceleration sensor, an angular velocity sensor, and a geomagnetic sensor, and includes the steps of: estimating a first attitude of the wireless terminal using sensor values ​​detected by the sensor unit; calculating a first angle of arrival of a first radio wave transmitted to the wireless terminal from a radio anchor installed at a predetermined position and a first distance between the radio anchor and the wireless terminal based on the first radio wave; and estimating a first position of the wireless terminal using the first angle of arrival and the first distance. The method includes the steps of: estimating a second position of the wireless terminal using a predetermined method that does not use the first angle of arrival; estimating a three-dimensional rotation matrix that equates a first relative vector from the first position to the position of the radio anchor with a second relative vector from the second position to the position of the radio anchor, and correcting the first attitude using the three-dimensional rotation matrix to generate a second attitude; and estimating a terminal position of the wireless terminal using the second position and a relative movement vector of the wireless terminal calculated by inertial navigation based on the second attitude.

[0009] By using the positioning system, positioning device, positioning method, and positioning program of the present disclosure, it is possible to improve the accuracy of measuring the position of a wireless terminal.

[0010] FIG. 1 is a schematic diagram (part 1) showing the configuration of a positioning system according to embodiment 1. FIG. 2 is a schematic diagram (part 2) showing the configuration of a positioning system according to embodiment 1. FIG. 3 is a block diagram showing the configuration of a positioning system and a positioning device according to embodiment 1. FIG. 4 is a diagram showing a terminal coordinate system based on the housing of a wireless terminal. FIG. 5 is a diagram showing an example of the hardware configuration of a positioning system and a positioning device according to embodiment 1. FIG. 6 is a diagram showing an ENU coordinate system. FIG. 7 is a flowchart showing the operation of an inertial navigation unit according to embodiment 1 to calculate the position of a wireless terminal. FIG. 8 is a schematic diagram (part 1) showing the configuration of a positioning system according to embodiment 2. FIG. 9 is a schematic diagram (part 2) showing the configuration of a positioning system according to embodiment 2. FIG. 10 is a block diagram showing the configuration of a positioning system and a positioning device according to embodiment 2. FIG. 11 is a diagram showing an anchor coordinate system based on the housing of a radio anchor.

[0011] Hereinafter, a positioning system, a positioning device, a positioning method, and a positioning program according to embodiments will be described with reference to the drawings. The following embodiments are merely examples, and the embodiments can be appropriately combined and modified. In addition, in the drawings, components having the same or similar functions are assigned the same reference numerals.

[0012] 1 and 2 are schematic diagrams (parts 1 and 2) showing the configuration of a positioning system 1 according to the first embodiment. １ 1 and 2 show an example in which a user 200 carrying a wireless terminal 10 moves from the position shown in Fig. 1 to the position shown in Fig. 2, and the attitude of the wireless terminal 10 changes from the attitude shown in Fig. 1 to the attitude shown in Fig. 2.

[0013] In Fig. 1, the positioning system 1 includes a radio wave anchor 20 (20a) and a wireless terminal 10. In Fig. 2, the positioning system 1 includes a radio wave anchor 20 (20b) and a wireless terminal 10. However, the positioning system 1 may be configured with a plurality of radio wave anchors 20 (for example, 20a, 20b) and a wireless terminal 10. The wireless terminal 10 is, for example, a mobile terminal with a wireless communication function such as a smartphone. The radio wave anchor 20 is a device equipped with a communication unit (401 in Fig. 5 described later) that transmits and receives radio waves to and from the wireless terminal 10, and is installed at a predetermined installation position x such as the ceiling or wall of a building 100. １ (for example, at a position whose absolute coordinates are known).

[0014] 3 is a block diagram showing a schematic configuration of a positioning system 1 and a positioning device 11 according to the first embodiment. The positioning device 11 is a device capable of measuring the position of a wireless terminal 10, which is a target device. The positioning device 11 is a device capable of implementing the positioning method according to the first embodiment. The positioning device 11 is also a device capable of executing the positioning program according to the first embodiment.

[0015] The wireless terminal 10 has a sensor unit 30 and a positioning device 11. The sensor unit 30 includes an acceleration sensor 31, a gyro sensor 32 as an angular velocity sensor, and a geomagnetic sensor 33. The positioning device 11 has an attitude estimation unit 40, a radio wave receiving unit 50, a first position estimation unit 60, a second position estimation unit 70, an attitude correction unit 80, and an inertial navigation unit 90. Although not shown in FIG. 3 , the wireless terminal 10 has various components for realizing the functions of a mobile terminal (e.g., a smartphone), such as a communication function with a public line network and a wireless communication function with a network.

[0016] The attitude estimation unit 40 estimates the attitude (i.e., the first attitude) of the wireless terminal 10 using the sensor values ​​(i.e., the output values ​​from the sensor unit 30) detected by the sensor unit 30. In other words, the first attitude is an attitude calculated based on the sensor values.

[0017] 4 is a diagram showing a terminal coordinate system (XYZ coordinate system) based on the housing of the wireless terminal 10. The radio wave receiving unit 50 is located at a predetermined installation position x １ Based on a first radio wave transmitted from a radio wave anchor 20 installed at a location on the wireless terminal 10, a first arrival angle of the first radio wave and a first distance l between the radio wave anchor 20 and the wireless terminal 10 are calculated. The first arrival angle of the first radio wave is defined by an azimuth angle θ and an elevation angle φ in the terminal coordinate system.

[0018] The first position estimation unit 60 estimates the first position x of the wireless terminal 10 using the first arrival angle (θ, φ) of the first radio wave and the first distance l. １ Estimate.

[0019] The second position estimation unit 70 estimates the second position x of the wireless terminal 10 using a predetermined method (described later) that does not use the first arrival angle (θ, φ). ２ Estimate.

[0020] The posture correction unit 80 determines the first position x １ From the installation position x of the radio wave anchor 20 １ The first relative vector r ｌ１ at the second position x ２ From the installation position x of the radio wave anchor 20 １ The second relative vector r ｌ２ and correcting the first pose using the three-dimensional rotation matrix to generate a second pose (i.e., a corrected pose).

[0021] The inertial navigation unit 90 calculates a relative movement vector Δx (described later) of the wireless terminal 10 calculated by inertial navigation based on the second attitude and a second position x ２ and estimate the position (i.e., corrected position) of the wireless terminal 10 using the above.

[0022] The attitude correction unit 80 corrects the first attitude to generate a second attitude at the timing when the sensor value becomes equal to or less than a predetermined threshold value.

[0023] Alternatively, the attitude correction unit 80 corrects the first attitude to generate the second attitude at the timing when the fluctuation component of the sensor value becomes equal to or less than a predetermined fluctuation threshold.

[0024] Alternatively, the attitude correction unit 80 corrects the first attitude to generate the second attitude at a timing when the ratio between the magnitude of the gravity direction component of the first relative vector and the magnitude of the gravity direction component of the second relative vector falls within a predetermined first range.

[0025] Alternatively, the posture correction unit 80 may calculate the first relative vector r ｌ１ and the length of the second relative vector r ｌ２ The first orientation is corrected to generate a second orientation at a timing when the ratio of the length of the first orientation to the length of the second orientation falls within a predetermined second range.

[0026] <<1-2>> Hardware Configuration> Fig. 5 is a diagram showing an example of the hardware configuration of the positioning system 1 and the positioning device 11 according to the first embodiment. The positioning system 1 includes a wireless terminal 10 and one or more radio anchors 20. The wireless terminal 10 includes a positioning device 11, a sensor unit 30, and an antenna 306. The positioning device 11 includes a processor 301 such as a CPU (Central Processing Unit), a memory 302 such as a RAM (Random Access Memory), a storage device 303 such as a non-volatile storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive), an interface 304, and a communication unit 305 that transmits and receives radio waves to and from the radio anchor 20 via the antenna 306. The wireless terminal 10 has a configuration for executing functions (for example, a function for communicating with a public line network, a function for wireless communication with a network) other than the configuration of the positioning device 11. The configuration of the positioning device 11 may be configured by a dedicated processing circuit.

[0027] The processor 301 can execute the positioning program according to the first embodiment. The positioning program is recorded on a recording medium such as an SD (Secure Digital) memory card or a USB (Universal Serial Bus) memory card, or is provided by downloading via a network, and is installed in the storage device 303.

[0028] The radio wave anchor 20 has an antenna 403 and a communication unit 401 for transmitting and receiving radio waves to and from the wireless terminal 10, and a control unit 402 for controlling the operation of the radio wave anchor 20. The control unit 402 and the antenna 403 are configured, for example, by dedicated processing circuits. The hardware configuration shown in Fig. 5 is an example, and various modifications are possible.

[0029] <1-3> Detailed Configuration <Sensor Unit 30> The acceleration sensor 31 detects acceleration components acting on the wireless terminal 10 and outputs acceleration values ​​as sensor values ​​based on commands from the attitude estimation unit 40. For example, the acceleration values ​​indicate acceleration components in the X-axis direction, Y-axis direction, and Z-axis direction in the terminal coordinate system of FIG.

[0030] The gyro sensor 32 detects angular velocity components acting on the wireless terminal 10 and outputs angular velocity values ​​as sensor values ​​based on commands from the attitude estimation unit 40. For example, the angular velocity values ​​indicate angular velocity components around the X-axis, the Y-axis, and the Z-axis in the terminal coordinate system of FIG.

[0031] The geomagnetic sensor 33 detects magnetic components acting on the wireless terminal 10 and outputs a magnetic force value as a sensor value based on a command from the attitude estimation unit 40. For example, the magnetic force value indicates magnetic force components in the X-axis direction, Y-axis direction, and Z-axis direction in the terminal coordinate system of FIG.

[0032] <Attitude Estimation Unit 40> The attitude estimation unit 40 estimates a first attitude, which is the attitude of the wireless terminal 10, using the acceleration value output from the acceleration sensor 31, the angular velocity value output from the gyro sensor 32, and the magnetic force value output from the geomagnetic sensor 33, and outputs the first attitude as terminal attitude information to the first position estimation unit 60 and the attitude correction unit 80. The attitude estimation unit 40 can estimate the first attitude of the wireless terminal 10 using a commonly known attitude estimation method. Usable attitude estimation methods include, for example, a method using an extended Kalman filter or a method using a Madgwick filter.

[0033] 6 is a diagram showing the ENU coordinate system. In FIG. 6, the X coordinate of the Earth Centered Earth Fixed (ECEF) spatial reference system is shown. ＥＣＥＦ , YＥＣＥＦ , Z ＥＣＥＦ 6, λ indicates longitude and β indicates latitude. FIG. 6 also shows coordinate axis E (eastward), coordinate axis N (northward), and coordinate axis U (upward as a direction against gravity) of the ENU coordinate system, which is a local coordinate system. In FIG. 6, the plane containing coordinate axis E and coordinate axis N is horizontal plane H, and coordinate axis U is a coordinate axis perpendicular to horizontal plane H.

[0034] The first attitude output from the attitude estimation unit 40 is an attitude in the terminal coordinate system (Figure 4) based on the housing of the wireless terminal 10, but can be transformed into the ENU coordinate system based on the current position using the following rotation matrix. This rotation matrix is ​​"R ｌ ｂ " is also written.

[0035] If a strong external magnetic field exists in the area where the wireless terminal 10 is placed, or if a residual magnetic field is generated in the electronic components inside the wireless terminal 10, an error will be superimposed on the sensor value of the geomagnetic sensor 33. In this case, the true terminal attitude of the wireless terminal 10 is calculated by Then, the rotation matrix R ｌ ｂ is the true terminal posture R ｌ ｂ＿ｔｒｕｅ and the correction rotation matrix C in three-dimensional space ｍｏｄｉｆｉｃａｔｉｏｎ Using the above, it can be expressed by the following equation (1).

[0036]

[0037] <Radio wave receiving unit 50> The radio wave receiving unit 50 receives the first radio wave transmitted from the radio wave anchor 20, calculates the first angle of arrival (θ, φ) of the first radio wave and the first distance l between the radio wave anchor 20 and the wireless terminal 10, and outputs them to the first position estimation unit 60.

[0038] The radio wave receiving unit 50 can estimate the first arrival angle (θ, φ) of the first radio wave and the first distance 1 by a commonly known method. For example, a method using Angle of Arrival (AoA) can be used to estimate the first arrival angle (θ, φ) of the first radio wave. A method using Time of Flight (TOF) can be used to estimate the first distance 1 between the radio wave anchor 20 and the wireless terminal 10.

[0039] As shown in FIG. 4, the first arrival angle (θ, φ) of the first radio wave is determined by the position of the housing of the wireless terminal 10 (first position x in FIG. 4). １ The angle of incidence can be defined by the azimuth angle θ and the elevation angle φ in the terminal coordinate system (XYZ coordinate system) based on the reference point (the reference point).

[0040] <First Position Estimation Unit 60> The first position estimation unit 60 estimates the first orientation R ｌ ｂ a first arrival angle (θ, φ) of the first radio wave; a first distance l between the radio wave anchor 20 and the wireless terminal 10; and an installation position x of the radio wave anchor 20. １ and the first position x １ Estimate.

[0041] First position x １ The method for estimating the distance x from the radio terminal 10 to the installation position x of the radio anchor 20 will be described in detail. １ The first relative vector r ｂ is expressed by the following equation (2) in the terminal coordinate system of FIG.

[0042]

[0043] The first relative vector r in the terminal coordinate system of FIG. ｂ Relative vector r converted into the ENU coordinate system ｌ１ is expressed by the following equation (3).

[0044]

[0045] First position x １ is the installation position x of the radio wave anchor 20 １ Using the above, it is expressed by the following equation (4).

[0046]

[0047] In addition, the positioning system 1 of embodiment 1 performs a first attitude correction between one wireless terminal 10 and one radio wave anchor 20, but the configuration may also be such that one wireless terminal 10 transmits and receives radio waves to and from multiple radio wave anchors 20 (e.g., 20a, 20b, ...).

[0048] In this case, a plurality of arrival angles and a plurality of distances are obtained, but it is desirable to select, for example, the combination of arrival angle and distance that results in the shortest distance and perform a similar calculation.

[0049] <Second Position Estimation Unit 70> The second position estimation unit 70 estimates the second position x , which is the terminal position, using a predetermined method that does not use the first arrival angle (θ, φ) of the first radio wave output from the radio wave receiving unit 50. ２ (Figure 4) is estimated.

[0050] Examples of predetermined methods that do not use the first arrival angle (θ, φ) include a method of calculating a position by receiving a GNSS (Global Navigation Satellite System) signal, or a method of calculating a position from an image of a camera installed on a building, etc. However, predetermined methods that do not use the first arrival angle (θ, φ) are not limited to these.

[0051] <Posture Correction Unit 80> The posture correction unit 80 corrects the first position x １ and the second position x ２ and the installation position x of the radio wave anchor 20 １ and the first attitude R of the wireless terminal 10 output from the attitude estimation unit 40. ｌ ｂ and the correction rotation matrix C of the first attitude of the wireless terminal 10 is calculated using the ｍｏｄｉｆｉｃａｔｉｏｎ Estimate.

[0052] Next, the correction rotation matrix C of the first orientation ｍｏｄｉｆｉｃａｔｉｏｎ A method for estimating the second position x ２ From the installation position x of the radio wave anchor 20 １ The second relative vector rｌ２ is the second position x ２ and the installation position x of the radio wave anchor 20 １ is expressed by the following equation (5).

[0053]

[0054] Here, the first position x １ From the installation position x of the radio wave anchor 20 １ The first relative vector r ｌ１ From equation (3), C ｍｏｄｉｆｉｃａｔｉｏｎ is related to the second relative vector r ｌ２ From equation (4), C ｍｏｄｉｆｉｃａｔｉｏｎ In this respect, the first relative vector r ｌ１ is the second relative vector r ｌ２ The rotation matrix in three-dimensional space that faces in the same direction as ｍｏｄｉｆｉｃａｔｉｏｎ This becomes:

[0055] Generally, the first position x １ and the second position x ２ Since errors are superimposed on the first relative vector r ｌ１ and the length of the second relative vector r ｌ２ The length of r is not equal to ｌ１ = α r ｌ２ By introducing a constant α that satisfies the above, the correction rotation matrix C ｍｏｄｉｆｉｃａｔｉｏｎ satisfies the following formula (6).

[0056]

[0057] Correction rotation matrix C ｍｏｄｉｆｉｃａｔｉｏｎ Since the degree of freedom of is 3, the correction rotation matrix C ｍｏｄｉｆｉｃａｔｉｏｎ The above is the correction rotation matrix C ｍｏｄｉｆｉｃａｔｉｏｎ This is the basis of the estimation method.

[0058] <Example of Processing for Improving Correction Accuracy> The attitude correction unit 80 corrects magnetic error components superimposed on the sensor value of the geomagnetic sensor 33 due to the influence of external magnetic fields and residual magnetic fields generated inside the device. While the wireless terminal 10 is in operation, the first attitude R ｌｂ Since errors instantaneously superimposed on the acceleration sensor 31 and the gyro sensor 32, and filter delay components of the extended Kalman filter or the Madgwick filter are superimposed on the above equation (1), the above equation (1) is further modified as shown in the following equation (7).

[0059]

[0060] Here, C ｔｅｍｐｏｒａｒｙ is a rotation matrix in three-dimensional space, and is an error component of the terminal attitude that is temporarily generated due to errors that are instantaneously superimposed on the gyro sensor 32 and the acceleration sensor 31 when the wireless terminal 10 is operating, and filter delay components of the extended Kalman filter and the Madgwick filter.

[0061] The rotation matrix C of the three-dimensional space in equation (7) ｔｅｍｐｏｒａｒｙ When this is substituted into equation (6), the following equation (8) is obtained.

[0062]

[0063] Therefore, the correction rotation matrix when the wireless terminal 10 is operating is C ｔｅｍｐｏｒａｒｙ C ｍｏｄｉｆｉｃａｔｉｏｎ The actual value we want to find is C ｍｏｄｉｆｉｃａｔｉｏｎ Therefore, C ｔｅｍｐｏｒａｒｙ The correction accuracy is improved by correcting the first attitude at a timing when the rotation component in the three-dimensional space due to the rotation matrix C in the three-dimensional space becomes small. ｔｅｍｐｏｒａｒｙ The timing when the three-dimensional rotation component due to the rotation becomes small is when the wireless terminal 10 is close to a stationary state.

[0064] Therefore, it is desirable that the attitude correction unit 80 performs the first attitude correction process of the wireless terminal 10 only when the sensor value of the acceleration sensor 31, the gyro sensor 32, or the geomagnetic sensor 33 is equal to or less than a predetermined threshold. For example, the attitude correction unit 80 performs the first attitude correction process when the acceleration value output from the acceleration sensor 31 is equal to or less than a predetermined acceleration threshold. Alternatively, the attitude correction unit 80 may perform the first attitude correction process when the angular velocity value output from the gyro sensor 32 is equal to or less than a predetermined angular velocity threshold. Alternatively, the attitude correction unit 80 may perform the first attitude correction process when the magnetic force value output from the geomagnetic sensor 33 is equal to or less than a predetermined magnetic force threshold. Alternatively, the attitude correction unit 80 may be configured to perform the first attitude correction process when the acceleration value is equal to or less than a predetermined acceleration threshold and the angular velocity value is equal to or less than a predetermined angular velocity threshold, or when the acceleration value is equal to or less than a predetermined acceleration threshold and the magnetic force value is equal to or less than a predetermined magnetic force threshold, or when the angular velocity value is equal to or less than a predetermined angular velocity threshold and the magnetic force value is equal to or less than a predetermined magnetic force threshold. Alternatively, the attitude correction unit 80 may be configured to perform the first attitude correction process when the acceleration value is equal to or less than a predetermined acceleration threshold, the angular velocity value is equal to or less than a predetermined angular velocity threshold, and the magnetic force value is equal to or less than a predetermined magnetic force threshold.

[0065] Furthermore, the attitude correction unit 80 may be configured to perform the first attitude correction process of the wireless terminal 10 only when the fluctuation component of the sensor value of the acceleration sensor 31, the gyro sensor 32, or the geomagnetic sensor 33 is equal to or less than a predetermined fluctuation threshold. For example, the attitude correction unit 80 may perform the first attitude correction process when the fluctuation component of the acceleration value output from the acceleration sensor 31 is equal to or less than a predetermined acceleration fluctuation threshold. Alternatively, the attitude correction unit 80 may perform the first attitude correction process when the fluctuation component of the angular velocity value output from the gyro sensor 32 is equal to or less than a predetermined angular velocity fluctuation threshold. Alternatively, the attitude correction unit 80 may perform the first attitude correction process when the fluctuation component of the magnetic force value output from the geomagnetic sensor 33 is equal to or less than a predetermined magnetic force fluctuation threshold. Alternatively, the attitude correction unit 80 may be configured to perform the first attitude correction process when the fluctuation component of the acceleration value is equal to or less than a predetermined acceleration fluctuation threshold and the fluctuation component of the angular velocity value is equal to or less than a predetermined angular velocity fluctuation threshold, or when the fluctuation component of the acceleration value is equal to or less than a predetermined acceleration fluctuation threshold and the fluctuation component of the magnetic force value is equal to or less than a predetermined magnetic force fluctuation threshold, or when the fluctuation component of the angular velocity value is equal to or less than a predetermined angular velocity fluctuation threshold and the fluctuation component of the magnetic force value is equal to or less than a predetermined magnetic force fluctuation threshold. Alternatively, the attitude correction unit 80 may be configured to perform the first attitude correction process when the fluctuation component of the acceleration value is equal to or less than a predetermined acceleration fluctuation threshold, the fluctuation component of the angular velocity value is equal to or less than a predetermined angular velocity fluctuation threshold, and the fluctuation component of the magnetic force value is equal to or less than a predetermined magnetic force fluctuation threshold.

[0066] With this configuration, the first attitude is corrected when the wireless terminal 10 is nearly stationary, improving the correction accuracy.

[0067] The first position estimation unit 60 estimates the first orientation R, which is the terminal orientation output from the orientation estimation unit 40. ｌ ｂ a first arrival angle (θ, φ) of the first radio wave output from the radio wave receiving unit 50, a first distance l between the radio wave anchor 20 and the wireless terminal 10, and an installation position x of the radio wave anchor 20. １ to find the first position x １However, there is a possibility that an error is superimposed on the first arrival angle (θ, φ) of the first radio wave output from the radio wave receiving unit 50. ２ The error superimposed on Δx １ Then, equation (6) is modified to the following equation (9).

[0068]

[0069] Here, C ｔｅｍｐｏｒａｒｙ１ is a rotation matrix in three-dimensional space, and the first position x １ The error Δx superimposed on １ This is the error component of the terminal attitude that occurs temporarily due to

[0070] Therefore, the first position x １ The correction rotation matrix when an error is superimposed on ｔｅｍｐｏｒａｒｙ１ C ｍｏｄｉｆｉｃａｔｉｏｎ The actual value we want to find is C ｍｏｄｉｆｉｃａｔｉｏｎ Therefore, C ｔｅｍｐｏｒａｒｙ１ Correction accuracy is improved by correcting the terminal attitude at a timing when the three-dimensional rotation component due to C becomes small. ｔｅｍｐｏｒａｒｙ１ The timing at which the three-dimensional rotation component due to the first position x １ This is when the error superimposed on the

[0071] Therefore, the attitude correction unit 80 may be configured to correct the attitude of the wireless terminal 10 when the ratio between the magnitude of the gravity direction component of the first relative vector and the magnitude of the gravity direction component of the second relative vector is equal to or less than a predetermined threshold. １ Since the terminal attitude is corrected when there is a high possibility that no error is superimposed on the terminal attitude, the correction accuracy is improved.

[0072] <Another Example of Processing for Improving Correction Accuracy> The second position estimation unit 70 estimates the second position x of the wireless terminal 10 using any method that does not use the first arrival angle (θ, φ) of the first radio wave. ２ However, there is a possibility that errors may be superimposed. ２ The error superimposed on Δx ２ Then, equation (6) is modified to the following equation (10).

[0073]

[0074] Here, C ｔｅｍｐｏｒａｒｙ２ is a rotation matrix in three-dimensional space, and the second position x ２ The error Δx superimposed on ２ This is the error component of the terminal attitude that occurs temporarily due to

[0075] Therefore, the second position x of the wireless terminal 10 ２ The correction rotation matrix when an error is superimposed on ｔｅｍｐｏｒａｒｙ２ C ｍｏｄｉｆｉｃａｔｉｏｎ The actual value we want to find is C ｍｏｄｉｆｉｃａｔｉｏｎ Therefore, C ｔｅｍｐｏｒａｒｙ２ Correction accuracy can be improved by correcting the terminal attitude at a timing when the three-dimensional rotation component due to C becomes small. ｔｅｍｐｏｒａｒｙ The timing at which the three-dimensional rotation component due to the rotation of the wireless terminal 10 becomes small is ２ This is when the error superimposed on the

[0076] Therefore, the process of correcting the terminal attitude of the wireless terminal 10 in the attitude correction unit 80 is performed by using the first relative vector r ｌ１ and the length of the second relative vector r ｌ２ The second position x of the wireless terminal 10 may be detected when the ratio of the length of the second position x to the length of the wireless terminal 10 is within a predetermined threshold range. ２ Since the terminal attitude is corrected when there is a high possibility that no error is superimposed on the terminal attitude, the correction accuracy is improved.

[0077] <Inertial navigation unit 90> The inertial navigation unit 90 calculates the position of the wireless terminal 10 using the second attitude, which is the terminal attitude obtained by correcting the first attitude, and the acceleration value. Figure 7 is a flowchart showing an example of the procedure of processing executed by the inertial navigation unit 90.

[0078] First, in step S1, the inertial navigation unit 90 calculates the second position x by the second position estimation unit 70. ２ If positioning is possible, the process proceeds to step S2, and if positioning is not possible, the process proceeds to step S3.

[0079] In step S2, the inertial navigation unit 90 calculates the second position x ２ This position x ｎｏｗ and the process ends.

[0080] In step S3, the inertial navigation unit 90 calculates a relative movement vector Δx of the wireless terminal 10. Here, the relative movement vector Δx is calculated by, for example, a method commonly known as pedestrian dead reckoning (PDR).

[0081] In step S4, the inertial navigation unit 90 calculates the previous position x ｂｅｆｏｒｅ and the relative movement vector Δx to find the current position x ｎｏｗ is calculated by the following formula (11).

[0082]

[0083] <<1-4>> Effects As described above, according to the first embodiment, the positioning system 1 and the positioning device 11 calculate a three-dimensional rotation matrix C such that a first relative vector when the radio anchor 20 is seen from the radio terminal 10, which is calculated using the first arrival angle (θ, φ) of the first radio wave received from the radio anchor 20 and the first distance l between the radio anchor 20 and the radio terminal 10, faces the same direction as a second relative vector when the radio anchor 20 is seen from the radio terminal 10, which is calculated using an arbitrary method that does not use the arrival angle of the radio wave. ｍｏｄｉｆｉｃａｔｉｏｎ In this way, the terminal attitude of the wireless terminal 10 is corrected, and therefore the terminal attitude of the wireless terminal 10 can be estimated with high accuracy. Furthermore, the terminal position is calculated by inertial navigation based on the corrected terminal attitude, and therefore the position of the wireless terminal 10 can be estimated with high accuracy.

[0084] 8 and 9 are schematic diagrams (part 1 and part 2) showing the configuration of a positioning system 1a according to embodiment 2. In FIG. 8 and FIG. 9, a building 100 and a predetermined installation position x of the building 100 are shown. １8 and 9 show an example in which the user 200 carrying the wireless terminal 10a moves from the position shown in Fig. 8 to the position shown in Fig. 9, and the attitude of the wireless terminal 10a changes from the attitude shown in Fig. 8 to the attitude shown in Fig. 9.

[0085] In the positioning system 1 (FIG. 3) according to the first embodiment, the second position estimation unit 70 of the positioning device 11 estimates the second position x by a method that does not use the first arrival direction (θ, φ), such as a method that uses a GNSS signal. ２ In contrast to this, in the positioning system 1a according to the second embodiment, the radio wave receiving unit (50b in FIG. 10) of the radio wave anchor 21 estimates the second arrival direction (θ １ , φ １ ) and the second distance (l in FIG. 11) between the radio anchor 21 and the wireless terminal 10a. １ ) and the second position estimation unit 70a calculates the second position x ２ An example of estimating is described below.

[0086] In Fig. 8, the positioning system 1a includes a radio wave anchor 21 (21a) and a wireless terminal 10a. In Fig. 9, the positioning system 1a includes a radio wave anchor 21 (21b) and a wireless terminal 10a. The wireless terminal 10a is, for example, a mobile terminal with a wireless communication function such as a smartphone. The radio wave anchor 21 is a device equipped with a communication unit (401 in Fig. 5) that transmits and receives radio waves to and from the wireless terminal 10a, and is installed at a predetermined installation position x such as the ceiling or wall of a building 100. １ (for example, at a position whose absolute coordinates are known).

[0087] 10 is a block diagram showing a schematic configuration of a positioning system 1a and a positioning device 11a according to the second embodiment. The positioning device 11a is a device capable of measuring the position of a wireless terminal 10a, which is a target device for positioning. The positioning device 11a is a device capable of implementing a positioning method according to the second embodiment. The positioning device 11a is also a device capable of executing a positioning program according to the second embodiment.

[0088] The wireless terminal 10a includes a sensor unit 30 and a positioning device 11a. The positioning device 11a includes an attitude estimation unit 40, a radio wave receiving unit 50a, a first position estimation unit 60, a second position estimation unit 70a, an attitude correction unit 80, and an inertial navigation unit 90. In the positioning system 1a according to the second embodiment, components having the same functions as those in the positioning system 1 according to the first embodiment are denoted by the same reference numerals.

[0089] The attitude estimation unit 40 estimates the attitude (i.e., the first attitude) of the wireless terminal 10a using the sensor values ​​(i.e., the output values ​​from the sensor unit 30) detected by the sensor unit 30. In other words, the first attitude is an attitude calculated based on the sensor values.

[0090] FIG. 11 shows the anchor coordinate system (X ａ Y ａ Z ａ The radio anchor 21 has a radio wave receiving unit 50b (FIG. 10). The radio terminal 10a is located at a predetermined installation position x １ The radio wave receiving unit 50b (FIG. 10) of the radio wave anchor 21 receives the second arrival angle (θ １ , φ １ ) and the second distance l between the radio anchor 21 and the wireless terminal 10a １ The second arrival angle of the second radio wave is calculated as an azimuth angle θ １ and elevation angle φ １ It is defined by:

[0091] The first position estimation unit 60 estimates the first position x of the wireless terminal 10a using the first arrival angle (θ, φ) of the first radio wave and the first distance l. １ Estimate.

[0092] The second position estimation unit 70a estimates the second position x of the wireless terminal 10a using a predetermined method that does not use the first arrival angle (θ, φ) of the first radio wave. ２ Examples of predetermined methods that do not use the first arrival angle (θ, φ) include a method of calculating the position by receiving a GNSS signal, or a method of calculating the position from an image from a camera installed on a building or the like. However, predetermined methods that do not use the first arrival angle (θ, φ) are not limited to these.

[0093] The attitude correction unit 80 adjusts the installation position x of the radio wave anchor 21. １ to the first position x １ The first relative vector r ｌ３ The radio wave anchor 21 is installed at the x position. １ to the second position x ２ The second relative vector r ｌ４ and correcting the first pose using the three-dimensional rotation matrix to generate a second pose (i.e., a corrected pose).

[0094] The inertial navigation unit 90 calculates a relative movement vector Δx (described later) of the wireless terminal 10a calculated by inertial navigation based on the second attitude and a second position x ２ and estimate the position (i.e., corrected position) of the wireless terminal 10a.

[0095] The attitude correction unit 80 corrects the first attitude to generate a second attitude at the timing when the sensor value becomes equal to or less than a predetermined threshold value.

[0096] Alternatively, the attitude correction unit 80 corrects the first attitude to generate the second attitude at the timing when the fluctuation component of the sensor value becomes equal to or less than a predetermined fluctuation threshold.

[0097] Alternatively, the posture correction unit 80 may calculate the first relative vector r ｌ３ The magnitude of the gravity direction component of the second relative vector r ｌ４ The first attitude is corrected to generate the second attitude at a timing when the ratio of the magnitude of the gravity direction component to the magnitude of the gravity direction component falls within a third predetermined range.

[0098] Alternatively, the posture correction unit 80 may calculate the first relative vector r ｌ３ and the length of the second relative vector r ｌ４ The first orientation is corrected to generate the second orientation at a timing when the ratio of the length of the first orientation to the length of the second orientation falls within a fourth predetermined range.

[0099] <<2-2>> Hardware Configuration The hardware configuration of the positioning system 1a and the positioning device 11a according to the second embodiment is the same as that shown in FIG.

[0100] <2-3> Detailed Configuration <Radio Wave Anchor 21> The radio wave anchor 21 receives the second radio wave transmitted from the wireless terminal 10a and calculates the second arrival angle (θ １ , φ １ ) and the second distance l between the radio anchor 21 and the wireless terminal 10a １ and transmits the calculated value to the wireless terminal 10a.

[0101] The second arrival angle (θ １ , φ １ The second distance l is estimated by, for example, a method using AoA. １ is estimated, for example, by a method using TOF.

[0102] The operation of the radio wave receiving unit 50a shown in Fig. 10 differs from the operation of the radio wave receiving unit 50 shown in Fig. 3. The radio wave receiving unit 50a calculates the first arrival angle (θ, φ) of the first radio wave and the first distance 1, similar to the radio wave anchor 20 (Fig. 3). In addition, the radio wave receiving unit 50a receives the second arrival angle (θ １ , φ １ ) and the second distance l between the radio anchor 21 and the wireless terminal 10a １ and outputs it to the second position estimation unit 70a.

[0103] The first position estimation unit 60 estimates the first position x of the wireless terminal 10a using the first arrival angle (θ, φ) of the first radio wave output from the radio wave receiving unit 50a, the first distance l between the radio wave anchor 21 and the wireless terminal 10a, and the position and attitude information of the radio wave anchor 21. １ This process is the same as in the first embodiment.

[0104] The second position estimation unit 70a estimates the second arrival angle (θ １ , φ １ ) and the second distance l between the radio anchor 21 and the wireless terminal 10a. １ and the position and attitude information of the radio anchor 21, the second position x ２ Estimate.

[0105] Second position x ２ The method for estimating the relative vector r as seen from the radio anchor 21 to the wireless terminal 10a will be described in detail. ａ is expressed by the following equation (12) in the anchor coordinate system based on the housing of the radio wave anchor 21.

[0106]

[0107] The rotation matrix for transforming from the anchor coordinate system (FIG. 11) to the ENU coordinate system (FIG. 6) is R ｌ ａ Then, the relative vector r in the anchor coordinate system ｌａ (ENU coordinate system) is expressed by the following equation (13).

[0108]

[0109] Second position x ２ is the installation position x of the radio wave anchor 21 １ is expressed by the following equation (14).

[0110]

[0111] The processes performed by the attitude correction unit 80 and the inertial navigation unit 90 are the same as those in the first embodiment.

[0112] <<2-3>> Effects As described above, according to the second embodiment, the second position estimation unit 70a of the wireless terminal 10a estimates the second arrival angle (θ １ , φ １ ) and the second distance l between the radio anchor 21 and the wireless terminal 10a １ , the second position x of the wireless terminal 10a is calculated. ２With this configuration, the terminal attitude can be corrected without using a GNSS signal or a camera installed in the building 100, etc., so that the configuration can be simplified and power saving effects can be achieved.

[0113] Except for the above, the second embodiment is the same as the first embodiment.

[0114] 1, 1a Positioning system, 10, 10a Wireless terminal, 11, 11a Positioning device, 20, 20a, 20b, 21, 21a, 21b Radio wave anchor, 30 Sensor unit, 31 Acceleration sensor, 32 Gyro sensor (rotation angle sensor), 33 Geomagnetic sensor, 40 Attitude estimation unit, 50, 50a Radio wave receiving unit, 50b Radio wave receiving unit, 60 First position estimation unit, 70, 70a Second position estimation unit, 80 Attitude correction unit, 90 Inertial navigation unit.

Claims

1. A positioning system for measuring the terminal position of a wireless terminal equipped with a sensor unit including an acceleration sensor, an angular velocity sensor, and a geomagnetic sensor, comprising: an attitude estimation unit for estimating a first attitude of the wireless terminal using sensor values ​​detected by the sensor unit; a radio wave receiving unit for calculating a first angle of arrival of a first radio wave and a first distance between the radio anchor and the wireless terminal based on a first radio wave transmitted to the wireless terminal from the radio anchor installed at a predetermined position; a first position estimation unit for estimating a first position of the wireless terminal using the first angle of arrival and the first distance; a second position estimation unit for estimating a second position of the wireless terminal using a predetermined method that does not use the first angle of arrival; and an attitude correction unit for estimating a three-dimensional rotation matrix such that a first relative vector viewing the position of the radio anchor from the first position is equal to a second relative vector viewing the position of the radio anchor from the second position, and correcting the first attitude using the three-dimensional rotation matrix to generate a second attitude; an inertial navigation unit that estimates a terminal position of the wireless terminal using a relative movement vector of the wireless terminal calculated by inertial navigation based on the second attitude and the second position.

2. The positioning system of claim 1, characterized in that the second position estimation unit estimates the second position using, as the predetermined method, a method of calculating a position by receiving a global navigation satellite system signal or a method of calculating a position from an image of a camera installed at a known location.

3. The positioning system described in claim 1, characterized in that the second position estimation unit estimates the second position using, as the predetermined method, a second angle of arrival of the second radio wave and a second distance between the radio anchor and the radio terminal, calculated by the radio anchor based on the second radio wave transmitted from the radio terminal to the radio anchor.

4. A positioning system according to any one of claims 1 to 3, characterized in that the attitude correction unit generates the second attitude at the timing when the sensor value becomes equal to or less than a predetermined threshold value.

5. A positioning system according to any one of claims 1 to 3, characterized in that the attitude correction unit generates the second attitude at the timing when the fluctuation component of the sensor value becomes equal to or less than a predetermined fluctuation threshold.

6. A positioning system as described in any one of claims 1 to 3, characterized in that the attitude correction unit generates the second attitude at a timing when the ratio between the magnitude of the gravity direction component of the first relative vector and the magnitude of the gravity direction component of the second relative vector is within a predetermined first range.

7. A positioning system as described in any one of claims 1 to 3, characterized in that the attitude correction unit generates the second attitude at a timing when the ratio between the length of the first relative vector and the length of the second relative vector falls within a predetermined second range.

8. A positioning device for measuring the position of a wireless terminal having a sensor unit including an acceleration sensor, an angular velocity sensor, and a geomagnetic sensor, comprising: an attitude estimation unit for estimating a first attitude of the wireless terminal using sensor values ​​detected by the sensor unit; a radio wave receiving unit for calculating a first angle of arrival of a first radio wave and a first distance between the radio anchor and the wireless terminal based on a first radio wave transmitted to the wireless terminal from the radio anchor installed at a predetermined position; a first position estimation unit for estimating a first position of the wireless terminal using the first angle of arrival and the first distance; a second position estimation unit for estimating a second position of the wireless terminal using a predetermined method that does not use the first angle of arrival; and an attitude correction unit for estimating a three-dimensional rotation matrix such that a first relative vector viewing the position of the radio anchor from the first position is equal to a second relative vector viewing the position of the radio anchor from the second position, and correcting the first attitude using the three-dimensional rotation matrix to generate a second attitude; an inertial navigation unit that estimates a terminal position of the wireless terminal using a relative movement vector of the wireless terminal calculated by inertial navigation based on the second attitude and the second position.

9. A positioning method implemented by a positioning system that measures the position of a wireless terminal equipped with a sensor unit including an acceleration sensor, an angular velocity sensor, and a geomagnetic sensor, comprising the steps of: estimating a first attitude of the wireless terminal using sensor values ​​detected by the sensor unit; calculating a first angle of arrival of a first radio wave and a first distance between the radio anchor and the wireless terminal based on a first radio wave transmitted to the wireless terminal from the radio anchor installed at a predetermined position; estimating a first position of the wireless terminal using the first angle of arrival and the first distance; estimating a second position of the wireless terminal using a predetermined method that does not use the first angle of arrival; estimating a three-dimensional rotation matrix that equates a first relative vector viewing the position of the radio anchor from the first position with a second relative vector viewing the position of the radio anchor from the second position, and correcting the first attitude using the three-dimensional rotation matrix to generate a second attitude; and estimating a terminal position of the wireless terminal using the second position and a relative movement vector of the wireless terminal calculated by inertial navigation based on the second attitude.

10. A positioning system for measuring the position of a wireless terminal equipped with a sensor unit including an acceleration sensor, an angular velocity sensor, and a geomagnetic sensor, comprising: a step of estimating a first attitude of the wireless terminal using sensor values ​​detected by the sensor unit; a step of calculating a first angle of arrival of a first radio wave and a first distance between the radio anchor and the wireless terminal based on a first radio wave transmitted from the radio anchor installed at a predetermined position to the wireless terminal; a step of estimating a first position of the wireless terminal using the first angle of arrival and the first distance; a step of estimating a second position of the wireless terminal using a predetermined method that does not use the first angle of arrival; a step of estimating a three-dimensional rotation matrix that equates a first relative vector viewing the position of the radio anchor from the first position with a second relative vector viewing the position of the radio anchor from the second position, and correcting the first attitude using the three-dimensional rotation matrix to generate a second attitude; and a step of estimating a terminal position of the wireless terminal using the second position and a relative movement vector of the wireless terminal calculated by inertial navigation based on the second attitude.

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