JP5849319B2 - Moving path estimation system, moving path estimation apparatus, and moving path estimation method - Google Patents

Description

  The present invention relates to a technique for estimating a moving path of an object, and more particularly to a technique for correcting a so-called gyro drift when a gyro sensor is used.

  A technique called Pedestrian Dead Reckoning (PDR) for the purpose of pedestrian navigation is known. In general, GPS (Global Positioning System), an azimuth sensor that uses geomagnetism, an acceleration sensor that detects acceleration, a gyro sensor that detects angular velocity, and the like are used to implement PDR. However, generally, GPS cannot be used indoors, and the accuracy of the orientation sensor may be significantly reduced. For this reason, in order to implement PDR indoors, it is necessary to estimate a walking route without depending on either absolute position information by GPS or absolute direction information by an orientation sensor.

  As an example of a method for realizing PDR indoors, a method of estimating a moving distance using an acceleration sensor and a moving direction using a gyro sensor can be considered. Since the gyro sensor detects the angular velocity, the relative azimuth | direction based on the direction of the gyro sensor in an initial position can be calculated | required by integrating this. However, it is known that the output value of the gyro sensor includes an offset (that is, the output does not become zero even though the sensor is not actually rotating). In general, the offset value is very small. However, when the offset value is integrated, the offset value is accumulated, so that the finally obtained relative orientation includes a large error. This phenomenon is called gyro drift. Since the offset value depends on temperature and the like, it is known that the value varies with time.

  Various offset correction methods have been proposed to reduce the influence of errors due to gyro drift. Patent document 1 is an example. The technique described in Patent Document 1 relates to an in-vehicle navigation device. Specifically, even when the vehicle is running, if the output of the gyro sensor is within a range defined by a predetermined upper limit value and lower limit value, it is determined that the vehicle is traveling straight, and the average of the outputs The value is obtained as an offset. The offset is corrected by subtracting the acquired offset value from the output value of the gyro sensor.

Japanese Patent Application Laid-Open No. 6-294652

  When the gyro sensor is attached to the pedestrian for estimating the walking route, it can be estimated that the value output from the gyro sensor when the pedestrian is not rotating is an offset. The state in which the pedestrian is not rotating includes not only the state in which the pedestrian is stationary but also the state in which the pedestrian is making direct progress. However, while traveling straight ahead, an angular velocity that greatly oscillates as a result of walking is output, so the offset could not be estimated from that value. The present invention has been made in view of the above problems, and estimates the offset from the output of the gyro sensor worn by the pedestrian and corrects the offset, thereby improving the accuracy of the walking path estimation using the gyro sensor. The goal is to improve.

  The present invention is a movement path estimation system including a terminal device attached to a moving body and a server device that acquires data from the terminal device, the terminal device having an angular velocity sensor and an acceleration sensor. The server device includes a processor and a storage device connected to the processor, and the storage device stores angular velocity data measured by the angular velocity sensor and acceleration data measured by the acceleration sensor. And the processor smoothes the angular velocity data, converts the smoothed angular velocity data into angular velocity data in an inertial coordinate system based on the acceleration data, and the inertial coordinate system in a predetermined length of time zone. The angular velocity variation around the Yaw axis at a time is less than or equal to a predetermined threshold, and the Y in the time zone When the angular velocity around the w axis is equal to or less than a predetermined threshold, the angular velocity around the Yaw axis is estimated as an offset value of the angular velocity around the Yaw axis, and is estimated from the angular velocity around the Yaw axis. By subtracting the offset value, the angular velocity around the Yaw axis is corrected, and based on the corrected angular velocity and the acceleration data, a horizontal moving path of the moving body is estimated, and the estimated moving path Is stored in the storage device.

  According to one embodiment of the present invention, it is possible to realize accurate walking path estimation using a gyro sensor.

It is a block diagram which shows the structure of the walking route estimation system of embodiment of this invention. It is a block diagram which shows the hardware constitutions of each part which comprises the walking route estimation system of embodiment of this invention. It is a flowchart which shows the walk route estimation process which the server apparatus of embodiment of this invention performs. It is a flowchart which shows the offset correction process of the gyro sensor which the server apparatus of embodiment of this invention performs. It is a flowchart which shows the estimation process of the offset amount of the gyro sensor which the server apparatus of embodiment of this invention performs. It is explanatory drawing of the angular velocity before smoothing measured by the gyro sensor of embodiment of this invention. It is explanatory drawing of the angular velocity measured and smoothed by the gyro sensor of embodiment of this invention. It is explanatory drawing of the frequency component peculiar to the walk contained in the angular velocity data measured in embodiment of this invention. It is explanatory drawing of the process which converts the angular velocity data measured in embodiment of this invention into the data in an inertial coordinate system. It is explanatory drawing of the angular velocity in the inertial coordinate system of the terminal device of embodiment of this invention. It is explanatory drawing of the dispersion | variation in the angular velocity around the Yaw axis | shaft of the terminal device of embodiment of this invention. It is explanatory drawing of the relative azimuth estimated by the server apparatus of embodiment of this invention. It is explanatory drawing of the walking route estimated by the server apparatus of embodiment of this invention. It is a 1st explanatory view of offset amount estimation based on the offset amount already estimated performed by the server apparatus of an embodiment of the present invention. It is a 2nd explanatory drawing of estimation of the offset amount based on the offset amount already estimated performed by the server apparatus of embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a walking route estimation system according to an embodiment of the present invention. FIG. 2 is a block diagram showing a hardware configuration of each unit constituting the walking route estimation system of the embodiment of the present invention.

  The walking route estimation system of this embodiment includes a terminal device 101, a server device 103, and a network 102 that connects them.

  The terminal device 101 is a terminal carried by a pedestrian, for example, a CPU (Central Processing Unit) 206, and a gyro sensor 201, an acceleration sensor 202, an orientation sensor 203, a temperature sensor 204, a GPS 205, and a memory 207 connected thereto. A storage medium 208, a communication unit 209, and an input / output unit 210.

  The gyro sensor 201 measures the angular velocity of the terminal device 101. Specifically, the gyro sensor 201 measures the angular velocities around the X axis, the Y axis, and the Z axis with respect to the orientation of the terminal device 101.

  The acceleration sensor 202 measures the acceleration of the terminal device 101. Specifically, the acceleration sensor 202 measures the acceleration in the axial directions of the X axis, the Y axis, and the Z axis with respect to the orientation of the terminal device 101.

  The direction sensor 203 detects geomagnetism and measures the absolute direction based on it.

  The temperature sensor 204 measures the temperature inside or around the terminal device 101. When the temperature dependence of the offset amount of the gyro sensor 201 is clear, the angular velocity measured by the gyro sensor 201 may be corrected using the temperature measured by the temperature sensor 204.

  The GPS 205 receives a signal from a GPS satellite and measures the absolute position of the terminal device 101 based on the signal.

  For example, the terminal device 101 uses the GPS 205 and the direction sensor 203 in an environment where the GPS 205 and the direction sensor 203 can be used, and uses the gyro sensor 201 and the acceleration sensor 202 in an environment where the GPS 205 and the direction sensor 203 cannot be used (for example, indoors). Necessary data may be collected. As will be described later, the present invention relates to walking path estimation using a gyro sensor 201 and an acceleration sensor 202. For this reason, although the terminal device 101 of this embodiment needs to be provided with the gyro sensor 201 and the acceleration sensor 202, the direction sensor 203, the temperature sensor 204, and GPS205 do not necessarily need to be provided.

  The CPU 206 controls the terminal device 101 according to a program stored in the memory 207.

  The memory 207 is a semiconductor memory, for example, and stores a program executed by the CPU 206, data referred to by the CPU 206, data acquired as a result of processing executed by the CPU 206, and the like. At least a part of the program and data stored in the storage medium 208 may be copied to the memory 207 as necessary, or the acquired data may be copied from the memory 207 to the storage medium 208 as necessary. Good.

  The storage medium 208 is a non-volatile storage medium such as a flash memory.

  The communication unit 209 is an interface that is connected to the network 102 and communicates with the server apparatus 103.

  The input / output unit 210 includes an input device that receives an input from a pedestrian wearing the terminal device 101 and an output device that outputs information to the pedestrian. For example, the input / output unit 210 may include a keyboard, a button, a pointing device, or the like as an input device, and may include an image display device or the like as an output device, or may include a so-called touch panel having functions equivalent to those. .

  For example, when a pedestrian enters a target area (for example, a specific building) from which a walking route is to be estimated, a data acquisition start instruction is input to the input / output unit 210, and data is An instruction to end acquisition may be input to the input / output unit 210. The CPU 206 controls the gyro sensor 201 and the acceleration sensor 202 from the start of data acquisition to the end thereof, for example, periodically measures the angular velocity and acceleration, and stores the results in the memory 207. To store. During this time, when the pedestrian walks around the target area, the angular velocity and acceleration resulting from the walking are measured and recorded.

  The server apparatus 103 is a computer including a CPU 212 and a communication unit 211, a memory 213, a storage medium 214, and an input / output unit 215 connected thereto.

  The CPU 212 executes, for example, a walking route estimation process to be described later according to a program stored in the memory 213.

  The memory 213 is, for example, a semiconductor memory, and stores a program executed by the CPU 212, data referred to by the CPU 212, data acquired as a result of processing executed by the CPU 212, and the like. At least a part of the program and data stored in the storage medium 214 may be copied to the memory 213 as necessary, or the acquired data may be copied from the memory 213 to the storage medium 214 as necessary. Good.

  The storage medium 214 is a non-volatile storage medium such as a hard disk or a flash memory.

  The communication unit 211 is an interface that is connected to the network 102 and communicates with the terminal device 101.

  The input / output unit 215 includes an input device that receives input from the user of the server device 103 and an output device that outputs information to the user. For example, the input / output unit 215 may include a keyboard, buttons, a pointing device, or the like as an input device, and may include an image display device or the like as an output device, or may include a so-called touch panel having functions equivalent to those. .

The network 102 may be any network as long as data can be transmitted from the terminal device 101 to the server device 103 via the network 102. For example, the network 102 may be a LAN, a wide area network, or a combination thereof. Alternatively, the network 102 may be a data transmission path such as a USB (Universal Serial Bus). FIG. 1 and FIG. 2 show a terminal apparatus 101 and a server apparatus 103 as typical examples of walking path estimation systems. However, instead of data communication via the network, data can be exchanged using a storage medium. For example, data measured by the gyro sensor 201 or the like is written in a replaceable storage medium such as a memory card connected to the terminal apparatus 101, and the storage medium is transported to the installation location of the server apparatus 103 to be server apparatus. The data written may be copied to the storage medium 214 or the memory 213.

  Alternatively, instead of the server device 103, the terminal device 101 itself may perform walking route estimation described later. In that case, the network 102 and the server apparatus 103 are unnecessary.

  FIG. 3 is a flowchart illustrating the walking route estimation process executed by the server device 103 according to the embodiment of this invention.

  As described above, the terminal device 101 stores the angular velocity data and the acceleration data measured by the gyro sensor 201 and the acceleration sensor 202 in the memory 207 or the storage medium 208 and transmits them to the server device 103 via the network 102. To do. For example, when the whole building having a plurality of floors is the target area for the walking route estimation, a pedestrian wearing the terminal device 101 enters the building and sequentially walks around each floor. Angular velocity data and acceleration data acquired during that time are stored in the storage medium 208 or the like. After the pedestrian walks around the entire floor, the terminal device 101 transmits data stored in the storage medium 208 or the like to the server device 103. The server apparatus 103 stores the angular velocity data and acceleration data received from the terminal apparatus 101 in the storage medium 214 and executes the walking route estimation process shown in FIG.

  First, the server apparatus 103 performs offset correction of the gyro sensor 201 with reference to the angular velocity data (step 301). Details of this processing will be described later with reference to FIG.

  Next, the server apparatus 103 estimates the amount of movement in the horizontal direction based on the acceleration data (step 302). This estimation can be performed by a conventionally known method. For example, the server device 103 may extract a horizontal component (that is, a component orthogonal to the vertical direction) from the three-dimensional acceleration data, and may estimate the amount of movement in the horizontal direction by integrating the extracted component. Whether or not a pedestrian is walking is determined based on the above, and when walking, the amount of movement may be estimated by multiplying the estimated step length by the number of steps.

  As described above, when acceleration data or the like in the entire building including a plurality of floors is acquired, the server apparatus 103 divides the data for each floor and estimates the amount of horizontal movement for each floor. To do. Whether the pedestrian has moved between the floors can be determined based on, for example, a pattern of acceleration data peculiar when the stairs are raised or lowered, or a pattern of acceleration data peculiar when the elevator is used. Alternatively, when a pedestrian moves between floors using stairs or the like, a floor break may be manually input to the terminal device 101.

  Next, the server apparatus 103 generates a pedestrian's movement trajectory based on the angular velocity data corrected in step 301 and the movement amount estimated in step 302 (step 303), and further generates the generated movement trajectory. Correction is made (step 304). Details of these processes will be described later (see FIGS. 12 and 13). The generated and corrected data indicating the movement locus may be stored in the memory 213 or the storage medium 214, and further, for example, a screen showing the movement locus may be displayed by the input / output unit 215.

  This is the end of the walking route estimation process.

  FIG. 4 is a flowchart illustrating offset correction processing of the gyro sensor 201 executed by the server apparatus 103 according to the embodiment of this invention. This process is executed in step 301 of the walking route estimation process shown in FIG.

  First, the server apparatus 103 smoothes the angular velocity data (step 401). Since the angular velocity data measured by the gyro sensor 201 includes a vibration component caused by walking, the server device 103 smoothes the value of the angular velocity by removing, for example, a frequency component peculiar to walking with a filter. Details of this processing will be described later (see FIGS. 6 to 8).

  Next, the server device 103 calculates the tilt angle of the terminal device 101 (step 402), and converts the angular velocity value into a value in the inertial coordinate system based on the tilt angle (step 403). The gyro sensor 201 measures angular velocities around each of the three axes (X axis, Y axis, and Z axis) that are orthogonal to each other. However, in general, the terminal device 101 is often attached to a pedestrian with the terminal device 101 tilted. In this case, the three axes of the terminal device 101 are the three axes of the inertial coordinate system, that is, the pedestrian's longitudinal axis (Roll axis). ), The pedestrian's horizontal axis (Pitch axis) and the pedestrian's vertical axis (Yaw axis) do not coincide. In order to generate a pedestrian's horizontal movement trajectory, it is necessary to specify an angular velocity around the Yaw axis (that is, a rotation component in the horizontal plane of the pedestrian's angular velocity). For this reason, the server apparatus 103 uses the acceleration data measured by the acceleration sensor 202 to convert the angular velocity value measured by the gyro sensor 201 into the angular velocity value in the inertial coordinate system (that is, the angular velocity value around the Roll axis). , Angular velocity values around the Pitch axis, and angular velocity values around the Yaw axis). Details of this conversion will be described later (see FIG. 9).

  Next, the server apparatus 103 estimates the offset amount of the gyro sensor 201 from the converted angular velocity values around the Yaw axis (step 404). Details of this processing will be described later (see FIG. 5 and the like).

  Next, the server apparatus 103 removes the estimated offset from the value of the angular velocity around the Yaw axis (step 405).

  Thus, the offset correction process of the gyro sensor 201 is completed.

  FIG. 5 is a flowchart illustrating an offset amount estimation process of the gyro sensor 201 executed by the server apparatus 103 according to the embodiment of this invention. This process is executed in step 404 of the offset correction process shown in FIG.

  First, the server apparatus 103 executes a loop process of steps 502 to 504 for a certain frame (step 501). Here, the frame is a frame on the time axis applied when calculating the variance of the angular velocity. For example, when the frame width is set to 2 seconds, the variance value of the angular velocity measured for 2 seconds converted by the gyro sensor 201 and converted into the inertial coordinate system is calculated. The width of the frame can be set arbitrarily. However, the gyro sensor 201 measures the angular velocity at a predetermined timing (for example, at predetermined intervals), and the server device 103 acquires a set of angular velocity sample values measured at each time from the terminal device 101 as angular velocity data. To do. For this reason, it is desirable to set the width of one frame so as to include a dispersion value and a sample value that can be calculated to a certain degree.

  The server apparatus 103 determines, for each frame, whether or not the angular velocity data included in the frame can be used for estimation of the offset amount (steps 502 and 503), and if it can be used, the offset amount based on the data. Is estimated (step 504). Since the offset amount of the gyro sensor 201 is a non-zero angular velocity value output from the non-rotating gyro sensor 201, the gyro sensor 201 is not rotating (that is, the terminal device 101 including the gyro sensor 201 is mounted). It can be estimated that the value of the angular velocity output when the pedestrian is not rotating) is the offset amount.

  Therefore, in order to estimate the offset amount of the gyro sensor 201 based only on the output of the gyro sensor 201, it is necessary to estimate whether or not the output of the gyro sensor 201 is caused by the rotational motion of the pedestrian. There is. Steps 502 and 503 are executed to estimate whether or not the output of the gyro sensor 201 is due to the rotational motion of the pedestrian. This estimation is based on the following concept.

  First, as long as humans are performing natural movements, the angular velocity when rotating the body is considered to have some variation. That is, it is unnatural for a human to perform an operation that rotates with a constant angular velocity, and the angular velocity during the period in which the pedestrian is rotating the body is not constant, and is considered to change greatly within that period. On the other hand, the offset amount of the gyro sensor 201 can change depending on the temperature or the like, but the change is considered to be extremely gradual as compared with the change in angular velocity due to the rotation of the pedestrian's body.

  Furthermore, as long as humans perform natural movements, the angular velocity when rotating the body is considered to have a certain magnitude. That is, it is considered unnatural for a human to perform an operation that rotates very slowly. On the other hand, the offset amount of the gyro sensor 201 that is generally distributed is extremely small.

  For this reason, when the variation in the angular velocity in the frame (for example, the variance value) is larger than a certain threshold value, or the magnitude of the angular velocity in the frame (for example, the average value) is larger than a certain threshold value, the angular velocity output at that time Can be estimated to be caused by the pedestrian's rotational movement, and if the angular velocity variation in the frame is less than or equal to a threshold value and the magnitude of the angular velocity in the frame is less than or equal to a threshold value, then It can be estimated that the output angular velocity is due to the offset of the gyro sensor 201 (that is, the magnitude of the angular velocity in the frame corresponds to the offset amount).

  Here, the magnitude of the angular velocity in the frame is a value that represents the sample value of the angular velocity in the frame, and is one of the sample values of the angular velocity in the frame (for example, the sample value that is the target of the offset amount estimation process, A maximum sample value in the frame, or a minimum sample value), or an arithmetic average value, a median value, or a mode value of the angular velocity sample value in the frame. . In the following description, the arithmetic average value of the sample values of the angular velocities in the frame is used as an example of these (see step 503 and the like).

  As a state in which the pedestrian is not performing the rotational motion, it is conceivable that the pedestrian is stationary (that is, a state in which the pedestrian is not walking and does not perform an operation such as direction change). In general, the output of the gyro sensor 201 when the pedestrian is stationary can be used to estimate the offset amount. On the other hand, since the output of the gyro sensor 201 when the pedestrian is performing an operation such as a change of direction or walking on a curve includes an angular velocity due to the rotational motion of the pedestrian, the offset Cannot be used for quantity estimation.

  On the other hand, a pedestrian who is traveling straight ahead does not perform a rotational movement macroscopically, but microscopically performs a rotational movement caused by vibration of walking. That is, the output of the gyro sensor 201 in that case has a large variation because it includes a vibration component caused by walking. However, if the component can be removed, it can be considered that the output of the gyro sensor 201 in the course of straight progress can be used for estimation of the offset amount. In the present embodiment, since the process of removing the vibration component caused by walking from the angular velocity data (that is, smoothing at step 401 in FIG. 4) is performed, variation in the output of the gyro sensor 201 caused by walking in a straight line. Is sufficiently small. For this reason, according to the present embodiment, it is possible to use the output of the gyro sensor 201 in the course of straight progress for estimation of the offset amount.

  Hereinafter, the processing after step 502 will be specifically described. First, the server apparatus 103 calculates a variance of sample values of angular velocities around the Yaw axis included in one frame, and determines whether the value is equal to or less than a predetermined threshold (step 502). If the calculated variance value is equal to or smaller than a predetermined threshold, the server apparatus 103 calculates an average of the sample values of angular velocities around the Yaw axis included in the frame, and whether or not the value is equal to or smaller than the predetermined threshold. Is determined (step 503). When it is determined in step 503 that the average value is equal to or less than the predetermined threshold, the server apparatus 103 estimates the average value as an offset amount in the time zone of the frame (step 504).

  Thereafter, the server apparatus 103 executes Steps 502 to 504 for the next frame.

  If it is determined in step 502 that the variance value exceeds the predetermined threshold value, or if it is determined in step 503 that the average value exceeds the predetermined threshold value, the server apparatus 103 does not execute step 504. The processing of steps 502 to 504 for the next frame is started.

  When the execution of steps 502 to 504 is completed for all frames, the server apparatus 103 next executes the loop processing of steps 506 and 507 for each sample value of angular velocity around the Yaw axis (step 505).

  First, the server apparatus 103 determines whether or not an offset amount in a time zone of a frame including the sample value is estimated for one sample value (step 506). If the offset amount is not estimated, that is, if the frame including the sample value is determined to be “No” in either step 502 or 503 and thus step 504 is not executed, the server apparatus 103 is estimated. Of the offset amounts, the one closest to the acquisition time of the sample value is estimated as the offset amount at the acquisition time of the sample value (step 507).

  The offset amount depends on the temperature and the like, and may vary with the passage of time. For this reason, for the sample value for which the offset amount could not be estimated in the loop of steps 502 to 504, the estimated offset amount at the time closest to the sample value acquisition time is used as the offset amount at the sample value acquisition time. presume.

  Thereafter, the server apparatus 103 executes Steps 506 and 507 for the next sample value.

  If it is determined in step 506 that the offset amount in the time zone of the frame including the sample value is estimated, it is not necessary to execute step 507, and therefore the server apparatus 103 executes step 507 for the sample value. Instead, the processing of steps 506 and 507 for the next sample value is started.

  In addition to the above, the offset amount estimation method in step 507 may have various modifications. A modification will be described later with reference to FIGS. 14 and 15.

  The estimation of the offset amount shown in FIG. 5 may be performed for each sample value or may be performed for each frame.

  First, the case where the offset amount is estimated for each sample value will be described. Here, as an example, it is assumed that the time width of the frame is 2 seconds from 1 second before to 1 second after the acquisition time of the sample value of the Yaw axis angular velocity that is the offset amount estimation target. In this case, the server apparatus 103 calculates a variance value and an average value of the sample values for 2 seconds before and after the target sample value (steps 502 and 503), and if these satisfy a predetermined condition, the calculation is performed. It is estimated that the average value is the offset amount included in the target sample value (step 504). Next, the server apparatus 103 performs the same process as described above on the sample value acquired next to the target sample value.

  Next, a case where the offset amount is estimated for each frame will be described. Here, as an example, the time width of the frame is assumed to be 2 seconds. In this case, the server apparatus 103 calculates a variance value and an average value of the sample values for 2 seconds corresponding to the frame whose offset amount is to be estimated (steps 502 and 503), and when these satisfy a predetermined condition The calculated average value is estimated to be an offset amount included in all sample values in the target frame (step 504). Next, the server apparatus 103 performs the same processing as described above for the frame for the next 2 seconds after the target frame.

  Although the accuracy of the offset amount estimated for each sample value can be expected to be higher than that estimated for each frame, the amount of calculation can be greatly reduced by estimating for each frame.

  Details of the processing shown in FIGS. 3 to 5 will be described below.

  FIG. 6 is an explanatory diagram of the angular velocity before smoothing, which is measured by the gyro sensor 201 according to the embodiment of the present invention.

  Specifically, FIG. 6 illustrates the measurement result of the angular velocity around the Yaw axis of the terminal device 101. This is an example of the value of the angular velocity before smoothing is performed in step 401 in FIG. As already described, the Yaw axis of the terminal device 101 (in other words, for example, the Z axis of the terminal device 101) does not necessarily match the Yaw axis of the inertial coordinate system (that is, the pedestrian's vertical direction). Similarly, the angular velocity around the pitch axis and the angular velocity around the roll axis of the terminal device 101 are also measured, but these are not shown.

  The horizontal axis of the graph of FIG. 6 is the time when the angular velocity is measured, and the vertical axis is the measured angular velocity (degree / second). The reason why the angular velocity shown in FIG. 6 vibrates greatly is that a vibration component caused by the walking of the pedestrian is included.

  FIG. 7 is an explanatory diagram of the angular velocity measured and smoothed by the gyro sensor 201 according to the embodiment of this invention.

  Specifically, FIG. 7 illustrates the result of smoothing the angular velocity data shown in FIG. 6 in step 401 of FIG. This smoothing is performed by removing frequency components peculiar to walking with a filter. The filter type may be any filter such as a low-pass filter (LPF) or a band-pass filter (BPF) as long as it can remove frequency components peculiar to walking. The structure of the filter to be used may be any filter such as an FIR (Finite Impulse Response) filter or an FFT (Fast Fourier Transform) filter. By executing step 401, components caused by walking are removed from the angular velocity data, and other components remain.

  FIG. 8 is an explanatory diagram of frequency components peculiar to walking included in the angular velocity data measured in the embodiment of the present invention.

  Specifically, FIG. 8 shows an example of a result of actual measurement of a pedestrian's pace (that is, the number of steps per second). The age of pedestrians is classified into adolescents, middle-aged and elderly, and actual results for men and women of each age are shown. According to this result, the pace becomes slower (that is, the value is smaller) as the age increases, and the male pace tends to be slower than the female pace, but the overall distribution is generally 1.6 to 2.4 steps / It can be seen that it is within the range of seconds, and the center is approximately 2.0 steps / second.

  This means that a frequency component peculiar to walking included in the angular velocity data can be almost eliminated by using an LPF having a cutoff frequency of 1.6 Hz or less. In the present embodiment, an LPF having a cutoff frequency of 1.6 Hz or less is used in step 401 of FIG.

  For example, the memory 213 or the storage medium 214 holds a parameter for realizing an LPF whose cutoff frequency is any value of 1.6 Hz or less (eg, 1.3 Hz), and the CPU 212 uses the parameter to appropriately The LPF may be realized by performing various calculations. As a specific calculation method for realizing the LPF, a conventionally known method can be used.

  In addition, this embodiment has shown walking path estimation when the terminal device 101 is attached to the pedestrian as an example. However, the present invention can also be applied when the terminal device 101 is attached to a moving body other than a pedestrian. The moving body other than the pedestrian may be, for example, a device that assists the movement of a human (for example, a bicycle, a car, a wheelchair, or the like), a human who moves using the device, or a robot or an animal other than a human. Etc. In that case, the memory 213 or the storage medium 214 holds a filter parameter for removing a specific frequency component when each moving body moves, and the CPU 212 performs an operation for removing the frequency component using the parameter. Also good.

  Further, the memory 213 or the storage medium 214 may hold parameters suitable for each of the plurality of mobile objects, and the CPU 212 may select and use parameters suitable for the type of mobile object to which the terminal device 101 is attached. . Alternatively, the memory 213 or the storage medium 214 holds a plurality of parameters (see FIG. 8) according to the age and sex of the pedestrian, and the CPU 212 selects a parameter that matches the attribute of the person to which the terminal device 101 is attached. May be used.

  FIG. 9 is an explanatory diagram of processing for converting angular velocity data measured in the embodiment of the present invention into data in an inertial coordinate system.

  A coordinate system 901 indicated by a solid line is an inertial coordinate system. That is, in the coordinate system 901, the X axis is the coordinate axis in the left-right direction of the pedestrian (that is, the Pitch axis), the Y axis is the coordinate axis in the front-rear direction of the pedestrian (that is, the Roll axis), and the Z axis is And the coordinate axis in the vertical direction, that is, the Yaw axis).

  On the other hand, a coordinate system 902 indicated by a dotted line is a coordinate axis of the terminal device 101. The X ′ axis, Y ′ axis, and Z ′ axis of the coordinate system 902 do not coincide with the X axis, Y axis, and Z axis in the coordinate system 901, respectively.

In step 402 of FIG. 4, the server apparatus 103 calculates the inclination angles θ _p and θ _r of the terminal apparatus 101 using the equations (1) and (2).

In the expressions (1) and (2), a _x , a _y, and a _z are an X′-axis direction component, a Y′-axis direction component, and a Z′-axis direction component, respectively, of gravitational acceleration. θ _p and θ _r are inclination angles of the terminal device 101 with respect to the inertial coordinate system, specifically, an angle around the X axis and an angle around the Y axis of the terminal device 101.

Next, the server apparatus 103 calculates θ _y ′, θ _p ′, and θ _r ′ by using equations (3) to (5) in step 403 in FIG. 4.

In equations (3) to (5), ω _x , ω _y, and ω _z are respectively the angular velocity around the X ′ axis, the angular velocity around the Y ′ axis, and the angular velocity around the Z ′ axis in the coordinate system 902 of the terminal device 101. Yes, these are the angular velocity data smoothed in step 401. θ _y ′, θ _p ′, and θ _r ′ are the angular velocity around the Z axis (Yaw axis), the angular velocity around the X axis (Pitch axis), and the Y axis (Roll axis), respectively, in the inertial coordinate system of the terminal device 101. Is the angular velocity. As described above, the angular velocities around the respective axes in the inertial coordinate system can be calculated using the equations (3) to (5). However, in the present invention, since the pedestrian's horizontal movement trajectory is estimated, the inertial coordinates Only angular velocities around the Yaw axis in the system are used.

  FIG. 10 is an explanatory diagram of the angular velocity in the inertial coordinate system of the terminal device 101 according to the embodiment of this invention.

  Specifically, the horizontal axis of the graph shown in FIG. 10 is time, and the vertical axis is angular velocity around the Yaw axis. FIG. 10 shows the angular velocities around the Yaw axis among the angular velocities in the inertial coordinate system calculated using the equations (1) to (5) from the angular velocities after smoothing including the Yaw axis angular velocities shown in FIG. Show. The time zone 1101 displayed in FIG. 10 will be described later (see FIG. 11).

  FIG. 11 is an explanatory diagram of variations in angular velocity around the Yaw axis of the terminal device 101 according to the embodiment of this invention.

  Specifically, the horizontal axis of the graph shown in FIG. 11 is time, and the vertical axis is the reciprocal of the variance of the angular velocity sample values. FIG. 11 shows the reciprocal of the variance value for each frame of the sample value of the angular velocity around the Yaw axis shown in FIG. This value is referred to in step 502 of FIG. As the value shown in FIG. 11 is larger, it means that the variance value of the sample value of the angular velocity included in the frame is smaller (that is, there is less variation). In the example of FIG. 11, a threshold “200” is set, and a time zone 1101 in which the reciprocal of the variance value exceeds the threshold is specified. In this case, the average value of the sample values of the angular velocity in the time zone 1101, that is, the average value of the sample values in the time zone 1101 shown in FIG. 10 is compared with a predetermined threshold value in Step 503. In the example of FIG. 10, the average value of the sample values in the time zone 1101 is very small but not zero. When it is determined that the average value is equal to or less than the predetermined threshold value, it is estimated that the average value is an offset amount (step 504 in FIG. 5).

  Thereafter, the server device 103 removes (ie, corrects) the offset by subtracting the estimated offset value from the angular velocity value (FIG. 10) in the inertial coordinate system (step 405 in FIG. 4).

  In the example of FIG. 11, in most time zones other than the time zone 1101, it is determined that the reciprocal of the variance value of the angular velocity sample value does not exceed the predetermined threshold value (that is, the variance value is equal to or less than the predetermined threshold value). Therefore, the offset amount is not estimated. As described above, when there is a time zone in which the offset amount cannot be estimated because the condition of either step 502 or step 503 in FIG. 5 is not satisfied, the server apparatus 103 sets the offset amount in the time zone to the step amount. It can be estimated based on the offset amount estimated in the time zone in which both of the conditions 502 and 503 are satisfied (step 507 in FIG. 5). This estimation can be performed by various methods as will be described later with reference to FIG. In FIG. 12 and FIG. 13, for the sake of simplicity of explanation, the offset amount estimated in the time zone 1101 is treated as the offset amount in all time zones.

  FIG. 12 is an explanatory diagram of relative azimuth angles estimated by the server apparatus 103 according to the embodiment of this invention.

  Specifically, the horizontal axis of the graph shown in FIG. 12 is time, and the vertical axis indicates relative azimuth. FIG. 12 shows a relative azimuth angle 1201 obtained by integrating the angular velocity shown in FIG. 10 without offset correction, and a relative azimuth angle 1202 obtained by integrating the angular velocity after offset correction. Indicates. Normally, the offset value is very small, but as the time is delayed by integrating the value, the difference in relative azimuth angle due to the presence or absence of correction increases.

  FIG. 13 is an explanatory diagram of a walking route estimated by the server device 103 according to the embodiment of this invention.

  The server apparatus 103 estimates a pedestrian's movement trajectory (walking route) based on the relative azimuth angle shown in FIG. 12 and the horizontal movement amount estimated from the acceleration data (step 303 in FIG. 3). However, since the relative azimuth is obtained in FIG. 12 and the absolute azimuth is unknown, the server device 103 performs, for example, map matching using the layout information of the building that is the target of the walking route estimation, An absolute orientation may be estimated (step 304). In that case, the storage medium 214 of the server apparatus 103 needs to hold layout information. Since map matching can be executed by a conventionally known method, detailed description thereof is omitted. Alternatively, when the terminal device 101 includes the azimuth sensor 203 and reliable information on the absolute azimuth is obtained thereby, it may be used.

  FIG. 13 shows estimated walking routes 1303 and 1304 from the start point 1301 to the end point 1302 of the floor 1305. The walking route 1304 is estimated based on the relative azimuth angle 1201 whose offset is not corrected, and the walking route 1303 is estimated based on the relative azimuth angle 1202 whose offset is corrected. The former largely deviates from the shape of the floor 1305, while the latter almost matches the shape of the floor 1305 and is considered to be close to the actual walking route.

  In this way, a route closer to the actual walking route can be estimated by correcting the offset. If the offset amount cannot be estimated unless the pedestrian is stationary, when walking along a route as shown in FIG. 13, unless the pedestrian is stationary at the start point 1301, the end point 1302, or any point in between, The offset amount cannot be estimated. However, according to the present invention, it is possible to estimate the offset amount from the angular velocity data during the straight progress even if there is no time zone in which the pedestrian is stationary between the start point 1301 and the end point 1302. .

  FIG. 14 is a first explanatory diagram of the offset amount estimation based on the already estimated offset amount, which is executed by the server apparatus 103 according to the embodiment of this invention.

In the example of FIG. 14, since both the conditions of steps 502 and 503 in FIG. 5 are satisfied in the time zone 1401 until time t ₁ and the time zone 1403 after time t ₂ , the offset amount (FIG. 14 (Value indicated by a solid line in the graph) is estimated. On the other hand, in the time zone 1402 from time t ₁ to t ₂ , the offset amount is not estimated because either of the conditions in step 502 or 503 in FIG. 5 is not satisfied.

In this case, for the sample value of the angular velocity in the time zone 1402, it is determined in step 506 in FIG. 5 that the offset amount has not been estimated, and step 507 is executed. In step 507, the server apparatus 103 determines the estimated offset amount at times adjacent to before and after the time zone 1402 in which the offset amount is not estimated (in the example of FIG. 14, the offset amount ω at each of the times t ₁ and t _2. Based on at least one of ₁ and ω ₂ ), an offset amount in the time zone 1402 is estimated.

For example, when a certain time in the time zone 1402 is closer to t ₁ than time t ₂ , the server apparatus 103 estimates that the offset amount at that time is the same as the offset amount ω ₁ at time t ₁ , and Is closer to t ₂ than time t ₁ , the offset amount at that time may be estimated to be the same as the offset amount ω ₂ at time t ₂ . The offset amount 1404 estimated in this way is illustrated in FIG.

Alternatively, the server apparatus 103 may estimate that the offset amount at all times in the time zone 1402 is the average value ω ₃ of the offset amounts ω ₁ and ω ₂ . The offset amount 1405 estimated in this way is illustrated in FIG.

Alternatively, the server apparatus 103, the offset amount omega ₁ at time t _1, by interpolating straight lines between the offset omega ₂ at time t _2, the may be estimated offset time zone 1402. This corresponds to a weighted average of ω ₁ and ω ₂ using the “closeness” between the time in the time zone 1402 and each of the times t ₁ and t ₂ as a weight. The offset amount 1406 thus estimated is illustrated in FIG.

In any case, the offset amount in the time zone 1402 takes any value in the range from ω ₁ to ω ₂ .

  FIG. 15 is a second explanatory diagram of the estimation of the offset amount based on the already estimated offset amount, which is executed by the server apparatus 103 according to the embodiment of this invention.

  As already described, in the present embodiment, frequency components resulting from human walking are removed from the angular velocity measured by the gyro sensor 201 and converted into values in the inertial coordinate system. For this reason, not only the angular velocity measured when the pedestrian is stationary (that is, not walking), but also the angular velocity measured when the pedestrian is moving straight forward can be used to estimate the offset amount. .

  However, when the pedestrian is at rest, it is almost impossible to move slowly, whereas when walking, the path is almost straight, but in reality it is extremely There is also a possibility of rotating slowly. In other words, it can be said that the angular velocity measured when the pedestrian is standing still is more reliable as the basis for estimating the offset amount than the angular velocity measured when the pedestrian is making a straight advance.

  For this reason, the server apparatus 103 determines whether or not the pedestrian was walking in each time zone, and the weight of the angular velocity measured in the time zone when not walking is heavier as shown in FIG. An estimation at 507 may be performed. Whether or not the pedestrian is walking can be determined by a conventionally known method based on the measured acceleration data.

  FIG. 15 shows an example in which it is determined that the pedestrian is walking in the time zone 1401 and it is determined that the pedestrian is stationary in the time zone 1403.

For example, the server apparatus 103 sets the offset amount at all times in the time zone 1402 as the time zone of the time zone 1403 in which the pedestrian is determined to be stationary among the time zones 1401 and 1403 adjacent to the time zone 1402. It may be estimated that it is the same as the angular velocity ω _{2 at} time t ₂ adjacent to 1402. The offset amount 1501 estimated in this way is illustrated in FIG.

Alternatively, when the server device 103 performs a weighted average similar to the offset amount 1406 of FIG. 14, the weight of the angular velocity ω ₂ in the time zone 1403 in which the pedestrian is stationary is used as the time zone in which the pedestrian is walking. You may set so that it may become heavier than the weight regarding the angular velocity (omega) ₁ in 1401. FIG. The offset amount 1502 estimated in this way is illustrated in FIG.

In any case, the offset amount in the time zone 1402 takes any value in the range from ω ₁ to ω _2, but is closer to time t ₁ than time t _3, which is an intermediate point between times t ₁ and t _2. The offset amount in the time period from time t ₄ to time t ₂ is estimated to be closer to ω ₂ than ω ₁ . In the example of the offset amount 1502 shown in FIG. 15, the offset amount ω _{4 at} time t ₄ is an intermediate value (that is, an average value) between ω ₁ and ω ₂ , and the time period from time t ₄ to time t ₂ The offset amount takes any value in the range from ω ₄ to ω ₂ .

  Thus, the weight of the offset amount estimated in the time zone in which it is determined that the pedestrian is stationary is heavier than the weight of the offset amount estimated in the time zone in which it is determined that the pedestrian is walking. As described above, it is possible to obtain a more reliable estimated value of the offset amount by estimating the offset amount in the time zone sandwiched between these time zones.

  Although the above explanation has been made on an example of estimating a walking path of an indoor pedestrian, the present invention can also be applied to estimating a moving path of a moving body other than a pedestrian, and further to an outdoor moving path estimation. Can be applied.

  According to the above-described embodiment of the present invention, by removing the vibration component caused by walking from the angular velocity data measured by the gyro sensor 201, the pedestrian goes straight ahead as well. The offset amount of the gyro sensor 201 can be estimated from the angular velocity data at that time. This makes it possible to realize walking path estimation with higher accuracy. Furthermore, if the offset amount of the angular velocity data measured at a certain time cannot be estimated based on the angular velocity data in the time zone including that time, the offset amount estimated based on the angular velocity data at the times before and after that time is calculated. It is also possible to estimate the offset amount at that time. At this time, estimation accuracy can be improved by performing weighting based on whether or not the pedestrian is walking.

101 Terminal Device 102 Network 103 Server Device 201 Gyro Sensor 202 Acceleration Sensor 203 Direction Sensor 204 Temperature Sensor 205 GPS
206, 212 CPU
207, 213 Memory 208, 214 Storage medium 209, 211 Communication unit 210, 215 Input / output unit

Claims (15)

A moving path estimation system including a terminal device attached to a moving body and a server device that acquires data from the terminal device,
The terminal device includes an angular velocity sensor and an acceleration sensor,
The server device includes a processor and a storage device connected to the processor,
The storage device holds angular velocity data measured by the angular velocity sensor and acceleration data measured by the acceleration sensor,
The processor is
Smoothing the angular velocity data;
Based on the acceleration data, the smoothed angular velocity data is converted into angular velocity data in an inertial coordinate system,
The variation in angular velocity around the Yaw axis in the inertial coordinate system in a predetermined length of time zone is less than or equal to a predetermined threshold, and the magnitude of angular velocity around the Yaw axis in the time zone is a predetermined threshold. If the following, the magnitude of the angular velocity around the Yaw axis is estimated as an offset value of the angular velocity around the Yaw axis,
Correcting the angular velocity about the Yaw axis by subtracting the estimated offset value from the angular velocity about the Yaw axis;
Based on the corrected angular velocity and acceleration data, a horizontal movement path of the moving body is estimated,
A movement path estimation system characterized in that information indicating the estimated movement path is held in the storage device. The moving body is a pedestrian;
2. The movement path estimation system according to claim 1, wherein the processor smoothes the angular velocity data by removing frequency components peculiar to human walking.   The movement path estimation system according to claim 2, wherein the processor removes a frequency component specific to human walking from the angular velocity data by a low-pass filter having a cutoff frequency of 1.6 Hz or less. .   The processor determines that the magnitude of the variation in angular velocity around the Yaw axis exceeds a predetermined threshold, or determines that the magnitude of angular velocity around the Yaw axis exceeds a predetermined threshold. An offset value of an angular velocity around the Yaw axis in a band, the estimated offset value in a second time period adjacent to the first time period and earlier than the first time period, and the first time period 2. The movement path estimation system according to claim 1, wherein the estimation is based on at least one of the estimated offset values in a third time zone that is adjacent to the first time zone and is later than the first time zone.   The processor may be any value in the range from the estimated offset value in the second time zone to the estimated offset value in the third time zone. The movement path estimation system according to claim 4, wherein an offset value of an angular velocity around the Yaw axis is estimated.   The processor determines whether the moving body has moved in each of the second time zone and the third time zone based on the acceleration data, and determines the second time zone and the third time zone. When it is determined that the moving body is stationary in one of the bands and the moving body is moving in the other band, the moving body is moving from the center during the first time period. The offset value in the range from the time close to the time zone to the time zone in which the mobile object was stationary is less than the estimated offset value in the time zone in which the mobile object was moving. 5. The offset value of the angular velocity around the Yaw axis in the first time zone is estimated so as to be close to the estimated offset value in a different time zone. Mounting movement path estimation system. The storage device holds a parameter of a filter for removing a frequency component specific to each of the plurality of types of the moving object,
The moving path estimation system according to claim 1, wherein the processor smoothes the angular velocity data using a filter to which a parameter corresponding to a type of a moving object to which the terminal device is attached is applied. . A movement path estimation device having a processor and a storage device connected to the processor,
The storage device holds angular velocity data measured by an angular velocity sensor attached to a moving body and acceleration data measured by an acceleration sensor attached to the moving body,
The processor is
Smoothing the angular velocity data;
Based on the acceleration data, the smoothed angular velocity data is converted into angular velocity data in an inertial coordinate system,
The variation in angular velocity around the Yaw axis in the inertial coordinate system in a predetermined length of time zone is less than or equal to a predetermined threshold, and the magnitude of angular velocity around the Yaw axis in the time zone is a predetermined threshold. If the following, the magnitude of the angular velocity around the Yaw axis is estimated as an offset value of the angular velocity around the Yaw axis,
Correcting the angular velocity about the Yaw axis by subtracting the estimated offset value from the angular velocity about the Yaw axis;
Based on the corrected angular velocity and acceleration data, a horizontal movement path of the moving body is estimated,
A movement path estimation apparatus characterized in that information indicating the estimated movement path is held in the storage device. The moving body is a pedestrian;
9. The moving path estimation apparatus according to claim 8, wherein the processor smoothes the angular velocity data by removing frequency components peculiar to human walking.   The processor determines that the magnitude of the variation in angular velocity around the Yaw axis exceeds a predetermined threshold, or determines that the magnitude of angular velocity around the Yaw axis exceeds a predetermined threshold. An offset value of an angular velocity around the Yaw axis in a band, the estimated offset value in a second time period adjacent to the first time period and earlier than the first time period, and the first time period The movement path estimation apparatus according to claim 8, wherein the estimation is based on at least one of the estimated offset values in a third time zone that is adjacent to the first time zone and is later than the first time zone.   The processor determines whether the moving body has moved in each of the second time zone and the third time zone based on the acceleration data, and determines the second time zone and the third time zone. When it is determined that the moving body is stationary in one of the bands and the moving body is moving in the other band, the moving body is moving from the center during the first time period. The offset value in the range from the time close to the time zone to the time zone in which the mobile object was stationary is less than the estimated offset value in the time zone in which the mobile object was moving. 11. The offset value of the angular velocity around the Yaw axis in the first time zone is estimated so as to be close to the estimated offset value in a different time zone. Movement path estimating device according. A movement path estimation method executed by a movement path estimation apparatus having a processor and a storage device connected to the processor,
The storage device holds angular velocity data measured by an angular velocity sensor attached to a moving body and acceleration data measured by an acceleration sensor attached to the moving body,
The moving route estimation method includes:
A first procedure for smoothing the angular velocity data;
A second procedure for converting the smoothed angular velocity data into angular velocity data in an inertial coordinate system based on the acceleration data;
The variation in angular velocity around the Yaw axis in the inertial coordinate system in a predetermined length of time zone is less than or equal to a predetermined threshold, and the magnitude of angular velocity around the Yaw axis in the time zone is a predetermined threshold. A third procedure for estimating the magnitude of the angular velocity around the Yaw axis as an offset value of the angular velocity around the Yaw axis if:
A fourth procedure for correcting the angular velocity around the Yaw axis by subtracting the estimated offset value from the angular velocity around the Yaw axis;
A fifth step of estimating a horizontal movement path of the moving body based on the corrected angular velocity and acceleration data, and holding information indicating the estimated movement path in the storage device. A moving route estimation method characterized by the following. The moving body is a pedestrian;
The moving path estimation method according to claim 12, wherein the first procedure includes a procedure of smoothing the angular velocity data by removing a frequency component peculiar to human walking.   In the third procedure, it is determined that the magnitude of variation in angular velocity around the Yaw axis exceeds a predetermined threshold, or the magnitude of angular velocity around the Yaw axis is determined to exceed a predetermined threshold. The offset value of the angular velocity around the Yaw axis in one time zone is set to the estimated offset value in the second time zone adjacent to the first time zone and earlier than the first time zone, and the first The movement according to claim 12, further comprising a step of estimating based on at least one of the estimated offset values in a third time zone that is adjacent to the time zone and is later than the first time zone. Route estimation method.   The third procedure determines whether the moving body has moved in each of the second time zone and the third time zone based on the acceleration data, and determines whether the second time zone and the second time zone When it is determined that the moving body is stationary in any one of the three time zones and the moving body is moving in the other time zone, the moving body moves from the center during the first time zone. The offset value in the range from the time close to the time zone in which the mobile object was stationary to the time zone in which the mobile object was stationary is greater than the estimated offset value in the time zone in which the mobile object was moving. And a step of estimating an offset value of the angular velocity around the Yaw axis in the first time zone so as to be close to the estimated offset value in the time zone. Moving path estimation method according to claim 14.

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