JP2011112500A - Sensor correction program, sensor correction device, and sensor correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct accurately an offset error included in detection values by a geomagnetic sensor and a gyro sensor. <P>SOLUTION: When acquiring a detection value detected by a sensor device 110, this sensor correction device 100, first of all, determines a sensor capable of outputting more accurate detection value out of a geomagnetic sensor 111 and a gyro sensor 112 from a traveling state of a moving body 130 (step S1). Then, a sensor detection value by the other sensor (sensor which is not determined to be the more accurate sensor in the step S1) is corrected by utilizing a detection value of the more accurate sensor (step S2). When correction in the step S2 is finished, the sensor correction device 100 outputs the detection value of the more accurate sensor and the corrected detection value to an azimuth detection device 120 (step S3), and finishes a series of sensor correction processing. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present disclosure relates to a sensor correction program, a sensor correction apparatus, and a sensor correction method for correcting an offset error between detection values of a geomagnetic sensor and a gyro sensor.

  Conventionally, when performing navigation targeting a moving body such as a pedestrian or a vehicle, a technique for correctly detecting the orientation of the moving body as a navigation target has been required. For example, in navigation, in order to realize a head-up function, a technique for detecting the orientation of a moving body is essential. As a technique for detecting the azimuth of a moving body, a method of mounting a gyro sensor or a geomagnetic sensor is widely used today.

  The geomagnetic sensor is a sensor that detects a magnetic field at the current position. Therefore, an absolute azimuth change can be detected by mounting the geomagnetic sensor on the moving body. On the other hand, the gyro sensor is a sensor that detects a change in angular velocity. Therefore, by mounting the gyro sensor on the moving body, it is possible to detect a relative azimuth change.

  Generally, an error is included in a detection value by a geomagnetic sensor or a gyro sensor. In the case of a geomagnetic sensor, errors are caused by errors in the sensor (such as differences in sensitivity between the X-axis and Y-axis directions), magnetic field interference generated inside the mounted device, external magnetic field interference, and tilting of the sensor. There are five factors such as tilt error and magnetic field disturbance due to contact with a strong magnet.

  FIG. 24 is an explanatory diagram showing error factors of the geomagnetic sensor. The error of the geomagnetic sensor can be determined by checking the locus on the Hx-Hy plane by measuring the magnetic field Hx in the X-axis direction and the magnetic field Hy in the Y-axis direction by rotating the compass once in the geomagnetism. Can be identified. When correct measurement is performed without error, an accurate circular trajectory is drawn as shown in FIG. 24 (A) Collective trajectory of xy output.

  However, if there is a sensitivity difference between the X-axis and the Y-axis of the geomagnetic sensor, the detected value on the low-sensitivity axis side becomes small and an ellipse is drawn, as in (B) XorY gain error. In addition, when a geomagnetic sensor is mounted on a mobile terminal or an in-vehicle device, a circle whose center is displaced from the origin is drawn as in (C) Offset error due to the influence of the magnetic field generated inside the mounted device. End up. In addition, when the detected values of the X-axis and Y-axis of the geomagnetic sensor interfere with each other due to an orthogonal failure, a tilted ellipse is drawn as in (D) XY interference.

  Furthermore, when the geomagnetic sensor is affected by an external magnetic field, the radius of the circle changes as in (E) Local noise field. For example, when an iron structure approaches the geomagnetic sensor, the magnetic field becomes strong and the radius of the circle increases (Large circle). On the other hand, when the geomagnetic sensor is placed indoors, the magnetic field becomes weaker and the radius of the circle becomes smaller (Small circle). As described above, the detection value of the geomagnetic sensor includes an error due to various factors. In particular, since the source of the magnetic field that generates the error is not fixed, the offset error is adjusted by adjusting the output of the geomagnetic sensor itself. Cannot be canceled properly.

  FIG. 25 is an explanatory diagram showing an offset error of the gyro sensor. A graph 2500 in FIG. 25 represents the relationship between the input [° / s] and the output [V] of the gyro sensor. As shown in the graph 2500, even when the gyro sensor is stationary, that is, when the input = 0, the output is not 0, but an output corresponding to the offset error occurs. A chart 2510 in FIG. 25 shows changes in offset error with time. As shown in the chart 2510, the offset error is caused by a temperature change, and causes a gentle and continuous deviation with time. The standard deviation of the amount of change in the offset error of the gyro sensor is called drift, and is regarded as important as an error representing the characteristics of the gyro sensor.

  As described above, the offset value is included in the detection values of the geomagnetic sensor and the gyro sensor. Therefore, in order to accurately detect the orientation of the moving body, the offset error must be corrected. However, it is difficult to cancel the error accurately because the factors causing the offset error (magnetic field and temperature of the mounted device) change as described above. Therefore, a mechanism that ensures that either the geomagnetic sensor or the gyro sensor is always accurate (for example, a value that regularly cancels the offset error from the outside) is provided to ensure accurate detection values. There is provided a technique for correcting the detection value of the other sensor by using the sensor (for example, refer to Patent Document 1 below).

Japanese Patent No. 2591192

  However, in the case of the prior art, one of the geomagnetic sensor and the gyro sensor is required to always obtain an accurate detection value. As described above, since the offset error is included in both the geomagnetic sensor and the gyro sensor, in order to correct one detection value, for example, an absolute value related to the orientation of the moving object is periodically acquired from the outside. A function for automatically canceling the offset error of the detected value is required.

  In order to maintain the accuracy of the detection value of one sensor, a receiving mechanism corresponding to the moving body must be provided in order to use a method of periodically obtaining an absolute value. In addition, since the information providing side also requires a communication infrastructure, the range of use is limited. Even if an absolute value related to the azimuth can be obtained from the outside, if the reception interval such as a beacon is wide, an offset error accumulates, and the accuracy of the detected value while the offset error is canceled decreases. Therefore, there is a problem that an accurate orientation cannot be detected.

  The present disclosure provides a sensor correction program, a sensor correction apparatus, and a sensor correction method for accurately correcting an offset error included in detection values of a geomagnetic sensor and a gyro sensor in order to solve the above-described problems caused by the prior art. With the goal.

  In order to solve the above-described problems and achieve the object, the present disclosure provides a computer that acquires detection values of a geomagnetic sensor and a gyro sensor mounted on a moving body and corrects an offset error included in the detection value. A process for determining whether or not the moving body is going straight ahead depending on whether the amount of change in the detection value of the geomagnetic sensor or the gyro sensor falls below a threshold value, and depending on whether or not the moving body is going straight ahead One of the geomagnetic sensor and the gyro sensor that can obtain an accurate detection value is identified, and the detection value of the other sensor is selected by selecting the detection value of the other sensor as a correction target. And correction processing using the detection value of the one sensor.

  According to the present sensor correction program, the sensor correction apparatus, and the sensor correction method, there is an effect that the offset error included in the detection values of the geomagnetic sensor and the gyro sensor can be accurately corrected.

It is explanatory drawing which shows an example of the sensor correction process concerning this Embodiment. It is a block diagram which shows the example of application of a sensor correction apparatus. It is a block diagram which shows the hardware constitutions of a sensor correction apparatus. It is a block diagram which shows the functional structure of a sensor correction apparatus. It is a flowchart which shows the procedure of the sensor correction process concerning this Embodiment. 3 is a flowchart illustrating an operation procedure of the sensor correction device according to the first embodiment. It is explanatory drawing which shows the relationship between an azimuth | direction vector and an offset error. It is explanatory drawing which shows the relationship between an azimuth | direction change amount and an azimuth | direction vector. 6 is a flowchart illustrating a procedure of straight-ahead determination / correction target selection processing according to the first exemplary embodiment. It is explanatory drawing showing the relationship between travel time and drift amount. 6 is a flowchart illustrating a procedure of sensor correction value calculation processing according to the first embodiment. 3 is a flowchart illustrating a procedure of geomagnetic sensor correction value calculation processing according to the first embodiment. 3 is a flowchart illustrating a procedure of direction information acquisition processing according to the first embodiment. It is a flowchart which shows the procedure of the direction change amount information acquisition process (at the time of geomagnetic sensor correction | amendment) in Example 1. FIG. 3 is a flowchart illustrating a procedure of gyro sensor correction value calculation processing according to the first embodiment. 5 is a flowchart illustrating a procedure of angular velocity information acquisition processing in the first embodiment. 6 is a flowchart illustrating a procedure of azimuth change amount information acquisition processing (during gyro sensor correction) according to the first exemplary embodiment. 6 is a flowchart illustrating a procedure of sensor correction processing according to the first exemplary embodiment. 3 is a flowchart illustrating a procedure of geomagnetic sensor correction processing according to the first embodiment. 6 is a flowchart illustrating a procedure of gyro sensor correction processing according to the first embodiment. 12 is a flowchart illustrating a procedure of straight ahead determination / correction target selection processing according to the second embodiment. It is explanatory drawing which shows the relationship between travel time and the error of the width direction of a vehicle position. It is a flowchart which shows the procedure of the direction change amount information acquisition process (at the time of geomagnetic sensor correction | amendment) in Example 2. FIG. It is a flowchart which shows the procedure of the azimuth | direction change amount information acquisition process (at the time of gyro sensor correction | amendment) in Example 2. FIG. It is a block diagram which shows the structural example (the 1) of the sensor correction apparatus using a some apparatus. It is a block diagram which shows the structural example (the 2) of the sensor correction apparatus using a some apparatus. It is explanatory drawing which shows the error factor of a geomagnetic sensor. It is explanatory drawing which shows the offset error of a gyro sensor.

  Exemplary embodiments of a sensor correction program, a sensor correction apparatus, and a sensor correction method according to the present invention will be explained below in detail with reference to the accompanying drawings.

(Embodiment)
FIG. 1 is an explanatory diagram showing an example of sensor correction processing according to the present embodiment. As shown in FIG. 1, in the present embodiment, it is possible to assist the traveling of the moving body 130 by acquiring information related to the movement of the moving body 130 using the in-vehicle device of the moving body 130. The in-vehicle device includes a sensor device 110, a sensor correction device 100, and an azimuth detection device 120 as a mechanism for obtaining information related to the movement of the moving body.

  The sensor device 110 includes a geomagnetic sensor 111 and a gyro sensor 112 as sensors that detect information related to the behavior of the moving body 130. The geomagnetic sensor 111 detects the absolute azimuth change amount by detecting the magnetic field at the current position of the moving body 130. The gyro sensor 112 detects a relative azimuth change amount by detecting a change in angular velocity of the moving body 130.

  Usually, the detection value detected by the sensor device 110 is provided to the azimuth detection device 120 as it is. Then, the direction detection device 120 detects the direction in which the moving body 130 has moved from the detection value of the sensor device 110. The detection result by the azimuth detecting device 120 is used for navigation processing of the moving body 130 or used for management of the moving body 130 by an external device (such as a vehicle management center). However, in actuality, the detection value of the sensor device 110 includes an offset error, and when the detection is performed using the detection value as it is, the detection result is highly likely to deviate from the actual direction. Therefore, in the present embodiment, the sensor correction device 100 is prepared between the sensor device 110 and the direction detection device 120 in order to cancel the offset error.

  As shown in FIG. 1, when the sensor correction device 100 acquires the detection value detected by the sensor device 110, first, the more accurate detection value of the geomagnetic sensor 111 and the gyro sensor 112 is determined from the traveling state of the moving body 130. Is determined (step S1). Then, the sensor correction apparatus 100 corrects the detection value of the sensor of the other sensor (the sensor that was not determined to be a more accurate sensor in Step S1) using the detection value of the more accurate sensor (Step S1). S2). When the correction in step S2 ends, the sensor correction device 100 outputs a more accurate sensor detection value and the corrected detection value to the azimuth detection device 120 (step S3), and ends a series of sensor correction processes. To do.

  FIG. 2 is a block diagram illustrating an application example of the sensor correction apparatus. In the present embodiment, the characteristics of each sensor are used in order to realize the sensor correction processing described with reference to FIG. Specifically, regardless of the presence or absence of an offset error, the detection value of the geomagnetic sensor 111 is constant while the moving body 130 is moving straight, and the detection value of the gyro sensor 112 in a short time is the offset value. Use the feature of being accurate regardless of the presence or absence of errors. Therefore, as shown in FIG. 2, the sensor correction apparatus 100 has a configuration in which the sensors correct each other using accurate detection values according to the traveling state of the moving body 130.

  The sensor correction apparatus 100 includes a selection unit 101 that selects which detection value of the geomagnetic sensor 111 or the gyro sensor 112 is to be corrected. The selection unit 101 has a straight-ahead determination function and a target selection function. When the selection unit 101 acquires the detection values of the geomagnetic sensor 111 and the gyro sensor 112, the selection unit 101 determines whether or not the moving body 130 is traveling straight using a straight traveling determination function. After that, the target selection function is used to select which detection value of the geomagnetic sensor 111 or the gyro sensor 112 is to be corrected.

  When the selection unit 101 selects that the detection value of the geomagnetic sensor 111 is to be corrected, the sensor correction for canceling the offset error included in the detection value of the geomagnetic sensor 111 is performed by the geomagnetic sensor correction value calculation unit 102. Calculate the value. The geomagnetic sensor correction value calculation unit 102 calculates an error in the detection value of the geomagnetic sensor 111 on the assumption that the detection value of the gyro sensor 112 is an accurate value.

  Similarly, when the selection unit 101 selects that the detection value of the gyro sensor 112 is a correction target, the gyro sensor correction value calculation unit 103 cancels the offset error included in the detection value of the gyro sensor 112. The sensor correction value is calculated. The gyro sensor correction value calculation unit 103 calculates an error in the detection value of the gyro sensor 112 on the assumption that the detection value of the geomagnetic sensor 111 is an accurate value.

  In the geomagnetic sensor correction unit 104 and the gyro sensor correction unit 105, the offset error included in the detection value using the sensor correction value calculated by the geomagnetic sensor correction value calculation unit 102 or the gyro sensor correction value calculation unit 103 in the preceding stage. Cancel. That is, when the detection value of the geomagnetic sensor 111 is selected by the selection unit 101, the geomagnetic sensor correction unit 104 calculates the sensor correction value calculated by the geomagnetic sensor correction value calculation unit 102 with respect to the detection value of the geomagnetic sensor 111. Correction processing using is performed. Similarly, when the detection value of the gyro sensor 112 is selected by the selection unit 101, the gyro sensor correction unit 105 performs sensor correction calculated by the gyro sensor correction value calculation unit 103 on the detection value of the gyro sensor 112. Correction processing using the value is performed.

  The detected value corrected by the geomagnetic sensor correction unit 104 or the gyro sensor correction unit 105 is input to the azimuth detection device 120 installed at the subsequent stage of the sensor correction device 100. Note that the detection value that has not been selected as the correction target in the selection unit 101 of the sensor correction apparatus 100 maintains high accuracy, and thus the detection value from the sensor is input to the azimuth detection apparatus 120 as it is.

  As described above, the offset error of the geomagnetic sensor 111 and the gyro sensor 112 mounted on the moving body 130 can be accurately corrected by using the sensor correction process according to the present embodiment. The direction detection device 120 receives detection values corrected with high accuracy in real time. Therefore, when the azimuth detecting device 120 detects the azimuth of the moving body 130 (such as positioning processing of the moving body 130), it is possible to detect the azimuth with high accuracy even when the azimuth information cannot be obtained from the outside. Become.

  Hereinafter, a specific configuration example and processing procedure of the sensor correction apparatus 100 that realizes the sensor correction processing as described above will be described in order.

(Hardware configuration of sensor correction device)
FIG. 3 is a block diagram illustrating a hardware configuration of the sensor correction apparatus. In FIG. 3, a sensor correction apparatus 100 includes a CPU (Central Processing Unit) 301, a ROM (Read-Only Memory) 302, a RAM (Random Access Memory) 303, a magnetic disk drive 304, a magnetic disk 305, and an optical disk. A drive 306, an optical disk 307, a communication I / F (Interface) 308, an input device 309, and an output device 310 are provided. Each component is connected by a bus 300.

  Here, the CPU 301 controls the entire sensor correction apparatus 100. The ROM 302 stores programs such as a boot program and a sensor correction program. The RAM 303 is used as a work area for the CPU 301. The magnetic disk drive 304 controls the reading / writing of the data with respect to the magnetic disk 305 according to control of CPU301. The magnetic disk 305 stores data written under the control of the magnetic disk drive 304.

  The optical disk drive 306 controls the reading / writing of the data with respect to the optical disk 307 according to control of CPU301. The optical disk 307 stores data written under the control of the optical disk drive 306, and causes the computer to read data stored on the optical disk 307.

  A communication interface (hereinafter abbreviated as “communication I / F”) 308 is connected to various networks such as a LAN (Local Area Network), a WAN (Wide Area Network), the Internet, and a local network through a communication line. Connected to other devices. The communication I / F 308 controls an internal interface with the network and controls data input / output from an external device. For example, a modem or a LAN adapter may be employed as the communication I / F 308.

  The input device 309 receives input from the outside to the sensor correction apparatus 100. Specific examples of the input device 309 include a keyboard and a mouse.

  In the case of a keyboard, for example, keys for inputting letters, numbers, and various instructions are provided, and data is input. Moreover, a touch panel type input pad or a numeric keypad may be used. In the case of a mouse, for example, the cursor is moved, a range is selected, or a window is moved or the size is changed. Further, a trackball or a joystick may be used as long as they have the same function as a pointing device.

  The output device 310 outputs detection values of the geomagnetic sensor 111 and the gyro sensor 112 corrected by the sensor correction apparatus 100, correction values used for correction, and the like. Specific examples of the output device 310 include a display and a printer.

  In the case of a display, for example, data such as a cursor, an icon or a tool box, a document, an image, and function information is displayed. Further, a CRT, a TFT liquid crystal display, a plasma display, or the like can be employed as this display. In the case of a printer, for example, image data and document data are printed. Further, a laser printer or an ink jet printer can be employed.

(Functional configuration of sensor correction device)
FIG. 4 is a block diagram illustrating a functional configuration of the sensor correction apparatus. The sensor correction apparatus 100 includes a straight traveling determination unit 401, a selection unit 402, a calculation unit 403, a correction unit 404, and an acquisition unit 405. Specifically, the functions (straight-line determination unit 401 to acquisition unit 405) serving as the control unit are, for example, sensor corrections stored in a storage device such as the ROM 302, RAM 303, magnetic disk 305, and optical disk 307 shown in FIG. The function is realized by causing the CPU 301 to execute the program or by an external device connected by the communication I / F 308.

  The straight traveling determination unit 401 has a function of determining whether or not the moving body 130 on which the sensor device 110 is mounted is traveling straight ahead. Specifically, the straight traveling determination unit 401 determines whether or not the moving body 130 is traveling straight in accordance with whether the amount of change in the detection value of the geomagnetic sensor 111 or the gyro sensor 112 falls below a threshold value. For example, the straight traveling determination unit 401 determines that the moving body 130 is traveling straight if the change amount of the detection value acquired from the geomagnetic sensor 111 is within a threshold value for a predetermined time or more, If the detected value acquired from the gyro sensor 112 is within a threshold value for a very short time, it may be determined that the moving body 130 is traveling straight. The determination result is stored in a storage area such as the RAM 303, the magnetic disk 305, and the optical disk 307.

  The selection unit 402 has a function of selecting a detection value to be corrected from detection values acquired from the sensor device 110. Specifically, the selection unit 402 has a function of selecting a detection value to be corrected from detection values acquired from the geomagnetic sensor 111 and the gyro sensor 112 based on the determination result of the straight traveling determination unit 401. The selection result is stored in a storage area such as the RAM 303, the magnetic disk 305, or the optical disk 307.

  The calculation unit 403 has a function of calculating a sensor correction value used for detection value correction processing. Specifically, the calculation unit 403 uses the correction value of the detection value of the sensor selected by the selection unit 402 as the amount of change of the detection value of the sensor not selected by the selection unit 402 over a predetermined time (accurately without error). Value). The calculated correction value is stored in a storage area such as the RAM 303, the magnetic disk 305, and the optical disk 307.

  The correction unit 404 has a function of correcting the detection value of the sensor that is the correction target by using the correction value calculated by the calculation unit 403. Specifically, the correction unit 404 uses the amount of change in the detection value of the sensor that has not been selected as the correction target by the selection unit 402, and determines how much the error in the amount of change in the detection value of the sensor selected as the correction target. The correction value is calculated by specifying whether or not it is included. The corrected detection value is stored in a storage area such as the RAM 303, the magnetic disk 305, or the optical disk 307.

  The acquisition unit 405 has a function of acquiring the detection value of the additional sensor 113. In the example of FIG. 4, the sensor device 110 mounted on the moving body 130 is configured by the geomagnetic sensor 111 and the gyro sensor 112 in an actual vehicle-mounted device, but there may be a case where only one of the sensors is mounted. is there. Moreover, although two sensors are mounted, there may be a situation where a failure occurs or a detection value cannot be acquired.

  Therefore, when the acquisition unit 405 can acquire only the detection value of one of the detection values of the sensor as described above, the acquisition unit 405 uses the detection value of the additional sensor 113 newly prepared in the moving body 130 to perform sensor correction. I do. Therefore, when only the detection value of the geomagnetic sensor 111 is acquired from the sensor device 110, the detection value of the additional sensor 113 is acquired from the acquisition unit 405 by preparing a sensor equivalent to the gyro sensor 112 as the additional sensor 113. Thus, sensor correction processing can be performed.

  Similarly, when only the detection value of the gyro sensor 112 is acquired from the sensor device 110, the detection value of the additional sensor 113 is used from the acquisition unit 405 by preparing a sensor corresponding to the geomagnetic sensor 111 as the additional sensor 113. Thus, sensor correction processing can be performed. The acquired detection value is stored in a storage area such as the RAM 303, the magnetic disk 305, and the optical disk 307.

  Note that when the sensor correction processing according to the present embodiment is realized, the sensor correction apparatus 100 only needs to include the straight-ahead determination unit 401 and the selection unit 402 as the minimum necessary configuration. That is, it is only necessary to discriminate a sensor in which a more accurate value is detected from detection values of the geomagnetic sensor 111 and the gyro sensor 112 and automatically select a correction target and a non-correction target. The sensor correction process in the subsequent stage may correct the detection value of the sensor that is the correction target by using the detection value of the sensor that is the non-correction target, and the specific correction method is not limited.

(Sensor correction procedure)
FIG. 5 is a flowchart showing a procedure of sensor correction processing according to the present embodiment. The flowchart of FIG. 5 shows a procedure from when the detection values acquired from each sensor mounted on the sensor device 110 are corrected to the output of the corrected detection values. By executing each process in FIG. 5, the offset error included in the detected value is canceled, so that a more accurate sensor correction process can be realized.

  In FIG. 5, first, the rectilinear determination unit 401 of the sensor correction device 100 determines whether or not the detection values of the geomagnetic sensor 111 and the gyro sensor 112 have been acquired (step S501). In step S501, it is determined that the detection value is acquired only when the detection values of both the geomagnetic sensor 111 and the gyro sensor 112 are acquired (step S501: Yes), and the process proceeds to step S503.

  In step S501, when the detection values of both the geomagnetic sensor 111 and the gyro sensor 112 are not acquired (step S501: No), the sensor device 110 can detect the additional sensor 113 if the additional sensor 113 is installed in the moving body 130. Sensor correction is performed using the detection value 113. Therefore, the acquisition unit 405 determines whether or not the detection value of the additional sensor 113 has been acquired (step S502). In step S502, when the acquisition unit 405 acquires the detection value (step S502: Yes), it is determined that the additional sensor 113 is set, and the sensor device 110 is acquired from the sensor device 110 and the additional sensor 113. Assuming that each detection value is used, the process proceeds to step S503.

  On the other hand, if the detection value is not acquired from the acquisition unit 405 in step S502 (step S502: No), it is determined that the additional sensor 113 is not prepared, and the process returns to step S501 to return to the sensor device. It will be in a standby state until the detection values of both the geomagnetic sensor 111 and the gyro sensor 112 are acquired from 110.

  When each detection value is acquired through steps S501 and S502, the straight-ahead determination unit 401 calculates a change amount of the detection value serving as a reference for the straight-ahead determination (step S503). It should be noted that each of the detected values of the geomagnetic sensor 111 and the gyro sensor 112 can be used as a reference for determining whether to go straight (see Examples 1 and 2 described later). Therefore, in step S503, the amount of change in the detection value of one of the sensors set in advance by the user of the sensor correction apparatus 100 may be calculated.

  Next, the straight traveling determination unit 401 determines whether or not the amount of change calculated in step S503 is less than a threshold value (step S504). If it is determined in step S504 that the amount of change is less than the threshold value (step S504: Yes), the straight traveling determination unit 401 determines that the moving body 130 is traveling straight (step S505). On the other hand, when it is determined in step S504 that the amount of change is not less than the threshold value (step S504: No), the straight traveling determination unit 401 determines that the moving body 130 is not traveling straight (step S506).

  Next, the selection unit 402 selects a sensor to be corrected by the sensor correction device 100 according to the determination result of the straight traveling determination unit 401 (step S507). Note that the selection criterion in step S507 differs depending on which detection value of the geomagnetic sensor 111 or the gyro sensor 112 is used for straight-ahead determination in step S503.

  When the sensor to be corrected is selected in step S507, the calculation unit 403 calculates the correction value of the sensor to be corrected using the detection value of the sensor to be non-corrected (step S508). When the correction value is calculated in step S508, the correction unit 404 corrects the detection value of the correction target sensor using the correction value (step S509). A series of sensor correction processing is completed by the above processing. The sensor correction process is sequentially executed in accordance with acquisition of detection values of the geomagnetic sensor 111 and the gyro sensor 112.

  Finally, it is determined whether or not the process of the sensor correction apparatus 100 is completed (step S510). If it is determined that the process is not completed, the process returns to step S501, and the process up to step S509 is repeated (step S509). S510: No loop). If it is determined in step S510 that the process has been completed (step S510: Yes), the sensor correction apparatus 100 ends the series of processes.

  Next, specific examples of sensor correction processing by the above-described sensor correction apparatus 100 will be described with reference to the first and second embodiments.

Example 1
In the first embodiment, it is determined whether or not the moving body 130 is traveling straight using the detection value of the geomagnetic sensor 111. And the sensor correction apparatus 100 correct | amends the offset error contained in the detection value of the gyro sensor 112 from the detection value of the geomagnetic sensor 111, when the moving body 130 is moving straight.

<Operation of sensor correction device>
FIG. 6A is a flowchart of the operation procedure of the sensor correction apparatus according to the first embodiment. The flowchart in FIG. 6A shows a procedure until the sensor correction device 100 corrects the detection value of each sensor acquired from the sensor device 110 and provides it to the azimuth detection device 120. By executing each process of FIG. 6A, accurate sensor correction can be performed without acquiring a new sensor or azimuth information from the outside.

  6A, first, the sensor correction apparatus 100 determines whether or not the power is on (step S601). Thereafter, the sensor correction apparatus 100 waits until it is determined that the power is turned on in step S601 (step S601: No loop). If it is determined that the power is turned on (step S601: Yes), first, straight-line determination is performed. / A correction target selection process is performed (step S602).

  When a sensor to be corrected is selected in step S602, the sensor correction apparatus 100 next performs a sensor correction value calculation process for correcting the detection value of the sensor to be corrected (step S603). The sensor correction apparatus 100 performs sensor correction processing to cancel the offset error of the detection value of the sensor selected as the correction target using the sensor correction value calculated in step S603 (step S604).

  By performing the processes in steps S602 to S604 described above, the offset included in the detection value with lower accuracy by using the detection value with higher accuracy among the detection values of the various sensors acquired from the sensor device 110. The error can be canceled automatically. In the sensor correction apparatus 100, when the process of step S604 ends, it is determined whether or not the power is off (step S605). In step S605, if the power supply is not in the OFF state (step S605: No), the sensor correction apparatus 100 returns to the process in step S602 and repeats the sensor correction process, and if it is determined that the power supply is in the OFF state (step S605: Yes). Then, a series of processing is completed.

  As described above, the sensor correction apparatus 100 first determines whether or not the moving body 130 is traveling straight, and selects a correction target according to the determination result. When determining whether or not the vehicle is traveling straight, the first embodiment uses the fact that the output of the geomagnetic sensor 111 is constant when the moving body 130 travels straight from the characteristics of the geomagnetic sensor 111.

  First, in the sensor correction device 100, the orientation of the moving body 130 obtained from the detection value of the geomagnetic sensor 111 is stable (for example, when the movement amount is longer than a certain time and the change amount of the azimuth is equal to or less than a threshold value ), It is determined that the moving body 130 is traveling straight. In addition, if the amount of change in magnetic flux density detected from the geomagnetic sensor 111 is less than or equal to the threshold value, the sensor correction apparatus 100 may determine that the vehicle is traveling straight because the direction is stable.

  If the moving body 130 is traveling straight, the moving body 130 does not rotate, and the angular velocity obtained as the detection value of the gyro sensor 112 is zero. Accordingly, since the amount of change in azimuth (Δθ) = 0, the relative azimuth obtained from the detection value of the gyro sensor 112 is also zero. Therefore, if the detection value of the gyro sensor 112 at time t1 is the sensor output V (t1), the detection value of the gyro sensor 112 at time t2 is the sensor output V (t2), the reference voltage Vo, the sensitivity Vs, and the offset error E. The relative azimuth angle can be expressed by the following equation (1). Therefore, the following equation (2) is established.

  The offset error (E) can be calculated by solving the above equation (2) for E. An accurate angular velocity can be output by recalculating the angular velocity using Vo + E as a new reference voltage.

  Further, in the case of the first embodiment, when it is determined that the moving body 130 is not traveling straight, the offset value included in the detection value of the geomagnetic sensor 111 is corrected using the detection value of the gyro sensor 112. The offset error of the gyro sensor 112 drifts due to external factors such as temperature. Therefore, the drift amount due to the offset error is small if the detection value of the gyro sensor 112 is short. Therefore, the output of the gyro sensor obtained by the short time operation of the moving body 130 is handled as an accurate value.

  FIG. 6B is an explanatory diagram of the relationship between the azimuth vector and the offset error. In FIG. 6B, the unit circle 621 is drawn on the basis of an orientation vector (Vr) composed of a correct magnetic flux density not including an error. Then, assuming that an azimuth vector (Vo) composed of magnetic flux densities (Hx, Hy) acquired by the geomagnetic sensor 111 and an offset error vector (Ve), the correct azimuth vector affected by the offset error is a unit circle 622. Draw. That is, it can be seen that the relationship is Vr = Vo−Ve.

  FIG. 6C is an explanatory diagram of a relationship between the direction change amount and the direction vector. A unit circle 631 represents the detected value of the change amount (Δθ) of the direction of the moving body from the time t1 to the time t2 by the gyro sensor 112. The gyro sensor 112 and the geomagnetic sensor 111 are time-synchronized, and azimuth vectors at time t1 are Vr1 and Vo1, and azimuth vectors at time t2 are Vr2 and Vo2.

  Each azimuth vector has a relationship of Vr1 = Vo1-Ve (formula (3)) and Vr2 = Vo2-Ve (formula (4)). The following formula (5) is established from Euler's formula.

  Therefore, substituting Equations (3) and (4) into Equation (5) to obtain Ve yields Equation (6) below, and an offset error can be obtained.

  Then, in order to further obtain Vr2, substituting the above equation (6) into the above equation (4), the following equation (7) is obtained, and the correct orientation vector (Vr2) is obtained. Finally, the azimuth θ can be calculated by obtaining the declination of the correct azimuth vector obtained by the following equation (7).

  In the first embodiment, the processes in steps S602 to S604 described above are performed using the characteristics described above. Therefore, detailed processing contents in each step will be described below.

<Straight line discrimination / correction target selection processing procedure>
FIG. 7 is a flowchart illustrating a procedure of straight-ahead determination / correction target selection processing according to the first embodiment. The flowchart in FIG. 7 shows detailed processing in step S602 in FIG. Specifically, it is determined whether or not the moving body 130 is going straight ahead, and the determination process is used to select which detection value of the geomagnetic sensor 111 and the gyro sensor 112 is to be corrected. Is shown. By executing each process of FIG. 7, a sensor outputting a more accurate detection value among the sensors mounted on the moving body 130 is specified.

  In FIG. 7, first, the sensor correction apparatus 100 acquires the magnetic flux density as a detection value from the geomagnetic sensor 111 (step S701). Next, the sensor correction apparatus 100 calculates an azimuth change amount from the acquired magnetic flux density (step S702). Further, the sensor correction device 100 calculates the moving time of the moving body 130 after starting the process of step S701 (step S703), and determines whether or not the moving time is equal to or greater than a threshold value (step S704).

  If it is determined in step S704 that the moving time is equal to or greater than the threshold (step S704: Yes), the sensor correction device 100 next determines whether or not the azimuth change amount is less than the threshold (step S705). . If it is determined in step S705 that the azimuth change amount is less than the threshold value (step S705: Yes), the sensor correction apparatus 100 determines that the straight traveling determination = true, that is, the moving body 130 is traveling straight (step). S706).

  If it is determined in step S704 that the movement time is not equal to or greater than the threshold value (step S704: No), or in step S705, the azimuth change amount is not less than the threshold value (step S705: No), the sensor correction device. 100 determines that the vehicle travels straight = false, that is, the moving body 130 is not traveling straight (step S707).

  Next, the sensor correction device 100 determines whether or not the straight-ahead determination is true (step S708). If the straight-ahead determination is true (step S708: Yes), the gyro sensor 112 is selected as a correction target (step S709). ), The process proceeds to step S603. On the other hand, in step S708, when straight-run determination = false (step S708: No), the geomagnetic sensor 111 is selected as a correction target (step S710), and the process proceeds to step S603.

<Relationship between travel time and drift amount>
As described above, the sensor correction apparatus 100 uses the moving time of the moving body 130 as a criterion for straight-running determination in step S704. Thereby, the drift of the detection value of the gyro sensor 112 is accumulated according to the elapsed time. Therefore, since the detection value of the gyro sensor 112 (when correction is not performed) after a certain period of time has passed, the detection value of the geomagnetic sensor 111 is used as a more accurate value. Therefore, in the first embodiment, the time t after the most recent correction process is calculated and applied to the determination in step S704.

  FIG. 8 is an explanatory diagram showing the relationship between the travel time and the drift amount. As shown in FIG. 8, the unit drift amount per time increases as the time t after the correction processing elapses as shown in the graph 810. Therefore, when the following setting is made, an error in angular velocity caused by drift after the elapse of time t is Dt.

t: Time after executing error correction [sec]
D: Gyro sensor drift [deg / sec / sec]
α: Required accuracy of application [deg]
(If a navigation device, α = about 10 deg)

  Therefore, the error of the angle caused by the drift after the elapse of time t is obtained by the following equation (8) (corresponding graph 820).

  As described above, when the required accuracy is α, it is necessary to correct the detection value of the gyro sensor 112 under the condition of the following equation (9). Therefore, in Example 1, it sets so that the detection value of the gyro sensor 112 may be corrected for every time t which satisfy | fills following (10) Formula.

<Sensor correction value calculation processing procedure>
FIG. 9 is a flowchart illustrating a procedure of sensor correction value calculation processing according to the first embodiment. The flowchart in FIG. 9 shows the detailed processing content of step S603. By performing each processing of FIG. 9, it is possible to calculate a sensor correction value for canceling the offset error of the sensor selected as the correction target.

  In FIG. 9, first, the sensor correction apparatus 100 determines whether or not the correction target is the geomagnetic sensor 111 (step S901). For which sensor is the correction target, refer to the selection result of the correction target in step S602. When it is determined in step S901 that the correction target is the geomagnetic sensor 111 (step S901: Yes), the sensor correction device 100 performs a geomagnetic sensor correction value calculation process (step S902), and proceeds to the process of step S604. . On the other hand, when it is determined in step S901 that the correction target is the gyro sensor 112 (step S901: No), the sensor correction device 100 performs a gyro sensor correction value calculation process (step S903). The process proceeds to step S604.

  Hereinafter, detailed processing in steps S902 and S903 will be described.

Geomagnetic Sensor Correction Value Calculation Process FIG. 10 is a flowchart showing the procedure of the geomagnetic sensor correction value calculation process in the first embodiment. The flowchart in FIG. 10 shows the detailed processing contents of step S902. By executing each process of FIG. 10, a sensor correction value for canceling the offset error can be calculated from the detection value of the geomagnetic sensor 111.

  In FIG. 10, the sensor correction apparatus 100 first acquires the azimuth information and the azimuth change amount information of the moving body 130 (steps S <b> 1001 and S <b> 1002). When both pieces of information are acquired, the sensor correction apparatus 100 next determines whether each acquired information, that is, the direction vector Vo1 at time t1, the direction vector Vo2 at time t2, and the direction change amount Δθ are not null. Judgment is made (step S1003).

  If it is determined in step S1003 that each piece of acquired information is not null (no value or inappropriate value) (step S1003: Yes), the sensor correction apparatus 100 uses the above equation (6) to calculate an offset error. The vector (Ve) is calculated (step S1004), and the process proceeds to step S604. On the other hand, if it is determined in step S1003 that each piece of acquired information is null (step S1003: No), the sensor correction apparatus 100 also sets the offset error vector (Ve) to null (step S1005) and performs the process of step S604. Migrate to

  Here, each information acquisition process in steps S1001 and S1002 will be described in detail.

  FIG. 11 is a flowchart illustrating the procedure of the orientation information acquisition process according to the first embodiment. The flowchart in FIG. 11 shows the detailed procedure of the orientation information acquisition process in step S1001. In FIG. 11, first, the detected value of the magnetic flux density (Hx, Hy) in the X direction and the Y direction is input from the geomagnetic sensor 111 to the sensor correction device 100 (step S1101).

Next, the sensor correction apparatus 100 calculates the azimuth angle (θ ′) using the following equation (10) (step S1102), and further calculates the azimuth vector (Vo) using the following equation (11) ( Step S1103).
θ ′ = atan (Hy / Hx) (10)
Vo = cos θ ′ + sin θ ′ (11)

  Then, the sensor correction apparatus 100 determines whether or not the direction vector Vo1 at time t1 is null (step S1104). If it is determined in step S1104 that Vo1 is null (step S1104: Yes), the sensor correction device 100 determines that the orientation vector Vo1 at time t1 has not been acquired, and the history 1 (Vo1) The direction vector (Vo) is stored (step S1105), and the process proceeds to step S1003.

  If it is determined in step S1104 that Vo1 is not null (step S1104: No), the sensor correction apparatus 100 further determines whether or not the direction vector Vo2 at time t2 is null (step S1106). If it is determined in step S1106 that Vo2 is null (step S1106: Yes), the sensor correction apparatus 100 determines that the orientation vector Vo2 at time t2 has not been acquired, and the history 2 (Vo2) The direction vector (Vo) is stored (step S1108), and the process proceeds to step S1003. If it is determined in step S1106 that Vo2 is not null (step S1106: No), the sensor correction apparatus 100 copies history 2 (Vo2) to history 1 (Vo1) (step S1107), and step S1108. Move on to processing.

  FIG. 12 is a flowchart illustrating a procedure of the azimuth change information acquisition process (during geomagnetic sensor correction) in the first embodiment. The flowchart in FIG. 12 shows a detailed procedure of the direction change amount information acquisition processing in step S1002. In FIG. 12, the sensor correction apparatus 100 first determines whether or not the time t1 is null (step S1201).

  If it is determined in step S1201 that the time t1 is null (step S1201: Yes), the sensor correction device 100 stores the timer output (t) in the history (t1) (step S1202), and further, the gyro sensor 112 The detected gyro output (V) is stored in the history (Vt1) (step S1203), and the process proceeds to step S1209.

  On the other hand, if it is determined in step S1201 that the time t1 is not null (step S1201: No), the sensor correction apparatus 100 further determines whether the time t2 is null (step S1204). When it is determined in step S1204 that the time t2 is null (step S1204: Yes), the sensor correction device 100 stores the timer output (t) in the history (t2) (step S1207), and further, the history ( The gyro output (V) is stored in V (t2)) (step S1208), and the process proceeds to step S1209.

  On the other hand, if it is determined in step S1204 that the time t2 is not null (step S1204: No), the sensor correction device 100 copies the history 2 (t2) to the history 1 (t1) (step S1205), and History 2 (V (t2)) is copied to history 1 (V (t1)) (step S1206), and the process proceeds to step S1207.

  Subsequently, the sensor correction apparatus 100 determines whether t1 and t2 are not null (step S1209). If it is determined in step S1209 that t1 and t2 are not null (step S1209: Yes), the sensor correction apparatus 100 acquires sensitivity (Vs) and reference voltage (Vb) (step S1210). Then, the sensor correction apparatus 100 calculates the azimuth change amount (Δθ) using the above equation (1) (step S1211), and proceeds to the process of step S1003. If it is determined in step S1209 that t1 and t2 are null (step S1209: No), the process directly proceeds to step S1003.

Gyro Sensor Correction Value Calculation Processing FIG. 13 is a flowchart illustrating a procedure of gyro sensor correction value calculation processing according to the first embodiment. The flowchart in FIG. 13 shows the detailed processing contents of step S903. By executing each process of FIG. 13, a sensor correction value for canceling the offset error can be calculated from the detection value of the gyro sensor 112.

  In FIG. 13, the sensor correction apparatus 100 first acquires angular velocity information and azimuth change amount information of the moving body 130 (steps S1301 and S1302). When both pieces of information are acquired, the sensor correction apparatus 100 next determines whether each acquired information, that is, the azimuth vector Vt1 at the time t1, the azimuth vector Vt2 at the time t2, and the azimuth variation Δθ is not null. Judgment is made (step S1303).

  If it is determined in step S1303 that each piece of acquired information is not null (no value or inappropriate value) (step S1303: Yes), the sensor correction apparatus 100 uses the above equation (1) to calculate an offset error. (E) is calculated (step S1304), and the process proceeds to step S604. On the other hand, if it is determined in step S1303 that each piece of acquired information is null (step S1303: No), the sensor correction apparatus 100 also sets the offset error (E) to null (step S1305) and performs the processing in step S604. Transition.

  Here, each information acquisition process in steps S1301 and S1302 will be described in detail.

  FIG. 14 is a flowchart illustrating a procedure of angular velocity information acquisition processing according to the first embodiment. The flowchart in FIG. 14 shows the detailed procedure of the angular velocity information acquisition process in step S1301. In FIG. 14, the sensor correction apparatus 100 first determines whether or not the time t1 is null (step S1401). If it is determined in step 1401 that the time t1 is null (step S1401: Yes), the sensor correction device 100 stores the timer output (t) in the history (t1) (step S1402), and proceeds to the process of step S1406. To do.

  On the other hand, if it is determined in step S1401 that the time t1 is not null (step S1401: No), the sensor correction device 100 further determines whether or not the time t2 is null (step S1403). If it is determined in step S1403 that the time t2 is null (step S1403: Yes), the sensor correction device 100 stores the timer output (t) in the history (t2) (step S1405), and the process of step S1406 Migrate to If it is determined in step S1403 that the time t2 is not null (step S1403: No), the sensor correction apparatus 100 copies the history 2 (t2) to the history 1 (t1) (step S1404), and step S1405. Move on to processing. Thereafter, the sensor correction apparatus 100 stores the gyro output (V) in the history DB (data base) (V (t)) (step S1406), and proceeds to the process of step S1303.

  FIG. 15 is a flowchart illustrating a procedure of direction change amount information acquisition processing (during gyro sensor correction) in the first embodiment. The flowchart in FIG. 15 shows the detailed procedure of the direction change amount information acquisition processing in step S1302. In FIG. 15, the sensor correction apparatus 100 sets the azimuth change amount (Δθ) to 0 (step S1501), and proceeds to the process of step S1303.

<Sensor correction procedure>
FIG. 16 is a flowchart illustrating the procedure of the sensor correction process in the first embodiment. The flowchart of FIG. 16 represents the detailed process of step S604 of FIG. By executing each process of FIG. 16, the detection value is corrected for canceling the offset error, and can be provided as a highly accurate detection value.

  In FIG. 16, first, the sensor correction apparatus 100 determines whether or not the correction target is the geomagnetic sensor 111 (step S1601). For which sensor is the correction target, refer to the selection result of the correction target in step S602. If it is determined in step S1601 that the correction target is the geomagnetic sensor 111 (step S1601: Yes), the sensor correction apparatus 100 performs a geomagnetic sensor correction process (step S1602), and proceeds to the process of step S605. On the other hand, if it is determined in step S1601 that the correction target is the gyro sensor 112 (step S1601: No), the sensor correction device 100 performs a gyro sensor correction process (step S1603), and proceeds to the process of step S605. .

  Hereinafter, detailed processing in steps S1602 and S1603 will be described.

  FIG. 17 is a flowchart illustrating the procedure of the geomagnetic sensor correction process according to the first embodiment. The flowchart in FIG. 17 shows the detailed procedure of the geomagnetic sensor correction process in step S1602. In FIG. 17, the sensor correction apparatus 100 first determines whether Vo2 and Ve are not null (step S1701). If it is determined in step S1701 that Vo2 and Ve are not null (step S1701: Yes), the sensor correction device 100 calculates a correct orientation vector (Vr2) (step S1702) and corrects it from the orientation vector (Vr2). The magnetic flux density (X, Y) is output (step S1703), and the process proceeds to step S605.

  On the other hand, if it is determined in step S1701 that Vo2 and Ve are null (step S1701: No), the sensor correction device 100 outputs the magnetic flux density (Hx, Hy) output from the geomagnetic sensor 111 as it is ( The process proceeds to step S1704) and step S605.

  FIG. 18 is a flowchart illustrating a procedure of gyro sensor correction processing according to the first embodiment. The flowchart in FIG. 18 shows the detailed procedure of the gyro sensor correction process in step S1603. In FIG. 18, first, the sensor correction apparatus 100 acquires a prescribed reference voltage (Vo) and sensitivity (Vs) (step S1801). Thereafter, the sensor correction device 100 calculates the correct reference voltage (Vo ′) from the correction value (E) (step S1802), and further calculates the angular velocity (ω) from the correct reference voltage (Vo ′). A value is output (step S1803), and the process proceeds to step S605.

(Example 2)
In the second embodiment, it is determined whether the moving body 130 is traveling straight using the detection value of the gyro sensor 112. And the sensor correction apparatus 100 correct | amends the offset error contained in the detection value of the geomagnetic sensor 111 from the detection value of the gyro sensor 112, when the mobile body 130 is moving straight ahead. In the second embodiment, the operation of the sensor correction apparatus 100 is similar to that shown in FIG.

  Also in the case of the second embodiment, as in the first embodiment, it is first determined whether or not the moving body 130 is traveling straight. When the moving body 130 is traveling straight, the offset value of the geomagnetic sensor is corrected using the detection value of the gyro sensor 112. Specifically, the fact that the detection value of the gyro sensor 112 is accurate for a short time is utilized. Therefore, when the detection value of the gyro sensor 112 is stable for a certain period of time (the change in the azimuth angle is equal to or less than the threshold value), it is determined that the moving body is traveling straight.

  In addition, the amount of change in angular velocity obtained as a detection value of the gyro sensor 112 may be used for determining whether the moving body 130 is going straight. Further, the direction of the moving body 130 obtained from the detection value of the gyro sensor 112 may be used. However, the azimuth of the moving body 130 is required to be stable while moving a certain distance because the accumulated error due to the moving distance is large.

  As described above, when it is determined that the moving body 130 is traveling straight, the azimuth angle change amount (Δθ) acquired from the gyro sensor 112 is zero. Therefore, the offset error of the gyro sensor 112 can be corrected by performing the same process as the correction method of the geomagnetic sensor of the first embodiment with Δθ set to 0.

  When the moving body 130 is not traveling straight, the offset value of the gyro sensor 112 is corrected using the detection value of the geomagnetic sensor 111. Specifically, the procedure is the same as the correction procedure of the gyro sensor 112 of the first embodiment. However, in the second embodiment, since the azimuth angle change amount (Δθ) is not 0, Δθ is obtained from the detection value of the geomagnetic sensor 111. Change to processing. Since the output error of the gyro sensor 112 drifts with time (see FIG. 8), the gyro sensor 112 is set so that the continuous energization time of the gyro sensor 112 is measured and the gyro sensor 112 is corrected when a predetermined time is exceeded. It may be.

  As described above, the overall procedure of the sensor correction process in the second embodiment is the same as that in the first embodiment, but the process contents are different in a part such as straight ahead determination and correction target selection. Therefore, in the following, a description will be given of a place where processing different from that in the first embodiment is performed in the sensor correction processing in the second embodiment.

  FIG. 19 is a flowchart illustrating a procedure of straight-ahead determination / correction target selection processing according to the second embodiment. The flowchart of FIG. 19 shows the detailed processing of the straight travel determination / correction target selection processing (corresponding to step S602 of FIG. 6-1) in the second embodiment. Specifically, it is determined whether or not the moving body 130 is going straight ahead, and the determination process is used to select which detection value of the geomagnetic sensor 111 and the gyro sensor 112 is to be corrected. Is shown. By executing each process of FIG. 19, a sensor that outputs a more accurate detection value among the sensors mounted on the moving body 130 is specified.

  In FIG. 19, first, the sensor correction apparatus 100 acquires an angular velocity as a detection value from the gyro sensor 112 (step S1901). Next, the sensor correction apparatus 100 calculates an azimuth change amount from the acquired angular velocity (step S1902). Further, the sensor correction apparatus 100 measures the moving time of the moving body 130 after starting the process of step S1901 (step S1903), and determines whether or not the measured time is less than the threshold value (step S1904). .

  If it is determined in step S1904 that the measurement time is less than the threshold value (step S1904: Yes), the sensor correction device 100 next determines whether or not the azimuth change amount is less than the threshold value (step S1905). . If it is determined in step S1905 that the azimuth change amount is less than the threshold value (step S1905: Yes), the sensor correction apparatus 100 determines that the straight traveling determination = true, that is, the moving body 130 is traveling straight ahead (step S1905). S1906).

  When it is determined in step S1904 that the measured time is not less than the threshold (step S1904: No), or in step S1905, it is determined that the azimuth change amount is not less than the threshold (step S1905: No), sensor correction The apparatus 100 determines that the vehicle travels straight = false, that is, the moving body 130 is not traveling straight (step S1907).

  Next, the sensor correction apparatus 100 determines whether or not the straight travel determination = true (step S1908). If the straight travel determination = true (step S1908: Yes), the geomagnetic sensor 111 is selected as a correction target (step S1909). ), The process proceeds to step S603. On the other hand, if it is determined in step S1908 that straight ahead determination = false (step S1908: No), the gyro sensor 112 is selected as a correction target (step S1910), and the process proceeds to step S603.

<Relationship between travel time and vehicle position width error>
As described above, in step S1904, the sensor correction apparatus 100 uses the measurement time of the moving body 130 as a reference for straight travel determination. In the case of the second embodiment, it is desired to use in a state where the error included in the detection value of the gyro sensor 111 is sufficiently small (almost no). Therefore, it is necessary to perform the sensor correction process within the time measured as the travel time within a predetermined value.

  FIG. 20 is an explanatory diagram showing the relationship between the travel time and the error in the width direction of the vehicle position. As shown in FIG. 20, the vehicle 130 performs autonomous positioning using the gyro sensor 112 and the vehicle speed pulse. When the following values are set, the sensor correction process may be executed within t ′.

L: Distance traveled by each vehicle speed pulse (m)
(Approximately 0.39m in JIS standard)
(The drive shaft is 637 rotations / km (JIS standard) ⇒1.57 m / rotation)
(If shaft rotation is 4 pulses, 0.39m / pulse)
D: Gyro sensor drift (deg / sec / sec)
t _n : cycle of the nth pulse of the vehicle speed pulse (sec)
β: Road width (m)
(2.75m for public roads: the minimum value of the width of public roads stipulated in the Road Structure Ordinance (Type 3 to Class 2 and Class 4 and Class 4 to Class 1 small roads, if the vehicle is in the middle of the road, (Vehicle position is 1.375m from road edge)
t ′: Time after executing error correction (sec)

The error θ ₁ of the angle caused by the drift after time t ₁ after the moving body 130 starts running is obtained by the following equation (11).

Further, the error in the width direction of the vehicle position P ₁ when the moving body 130 travels straight by L after time t ₁ is L sin (θ ₁ ). In addition, an error in angle caused by drift after time t ₁ + t ₂ is θ ₂ . Then, the error in the width direction of the vehicle position P ₂ when the moving body 130 travels straight by L after time t ₁ + t ₂ is Lsin (θ ₁ ) + Lsin (θ ₁ + θ ₂ ).

  Therefore, if the reliability of the gyro sensor 112 is defined so that the autonomous positioning result of the moving body 130 is within the road, the following equation (12) must be satisfied. Therefore, in the second embodiment, the sensor correction process is set to be performed within the time t ′ obtained by the following equation (13).

  FIG. 21A is a flowchart illustrating a procedure of direction change amount information acquisition processing (during geomagnetic sensor correction) according to the second embodiment. The flowchart in FIG. 21A illustrates a detailed procedure of the direction change amount information acquisition process according to the second embodiment. In FIG. 21A, the sensor correction device 100 sets the azimuth change amount (Δθ) to 0 (step S2100), and proceeds to the process of step S1003.

  FIG. 21-2 is a flowchart illustrating a procedure of the direction change amount information acquisition process (during gyro sensor correction) according to the second embodiment. The flowchart in FIG. 21B illustrates a detailed procedure of the direction change amount information acquisition process according to the second embodiment. In FIG. 21B, the sensor correction apparatus 100 first acquires detection values of magnetic flux densities (Hx, Hy) in the X direction and the Y direction from the geomagnetic sensor 111 (step S2101).

  Next, the sensor correction apparatus 100 calculates the azimuth angle (θ ′) using the above equation (11) (step S2102), and further determines whether θ1 is null (step S2103). If it is determined in step S2103 that θ1 is null (step S2103: Yes), the sensor correction apparatus 100 determines that the azimuth angle at time t1 has not been acquired, and the azimuth angle (θ in the history (θ1)). ) Is saved (step S2104), and the process proceeds to step S2108.

  If it is determined in step S2103 that θ1 is not null (step S2103: No), the sensor correction apparatus 100 determines whether θ2 is null (step S2105). If it is determined in step S2105 that θ2 is null (step S2105: Yes), the sensor correction device 100 determines that the azimuth angle θ2 at time t2 has not been acquired, and history 2 (θ2) The azimuth angle (θ) is stored (step S2107), and the process proceeds to step S2108. If it is determined in step S2105 that θ2 is not null (step S2105: No), the sensor correction apparatus 100 copies history 2 (θ2) to history 1 (θ1) (step S2106), and step S2107. Move on to processing.

  Thereafter, the sensor correction apparatus 100 determines whether θ1 and θ2 are not null (step S2108). If it is determined in step S2108 that θ1 and θ2 are not null (step S2108: Yes), an azimuth change amount (Δθ) is calculated (step S2109), and the process proceeds to step S1303. On the other hand, if it is determined in step S2108 that θ1 and θ2 are null (step S2108: No), the direction change amount (Δθ) is determined to be null (step S2110), and the process proceeds to step S1303.

  In addition, the geomagnetic sensor 111 and the gyro sensor 112 used in the first and second embodiments perform sensor correction through the above-described procedure regardless of the type of uniaxial, biaxial, and triaxial types. be able to.

(Combination of Examples 1 and 2)
The sensor correction apparatus 100 according to the present embodiment may realize processing using the above-described first and second embodiments together. Specifically, for example, there is a method of applying the sensor correction apparatus 100 that combines the first and second embodiments depending on where there is a magnetic disturbance. The environment in which magnetic disturbance occurs is, for example, that the output of the geomagnetic sensor 111 goes wrong when traveling on a road with many large trucks near a track. In an environment where there is a magnetic disturbance, the reliability of the output of the geomagnetic sensor 111 is lowered regardless of whether the vehicle travels straight or bends.

  Therefore, the gyro sensor 112 cannot be corrected using the geomagnetic sensor 111. In such a case, only the geomagnetic sensor 111 is corrected using the gyro sensor 112. Specifically, the straight-ahead determination uses the processing of the second embodiment, the sensor correction processing in the case of straight travel uses the second embodiment, and the sensor correction processing in the case of non-straight travel uses the first embodiment.

  As another example, the first and second embodiments may be combined when the gyro sensor 112 cannot be corrected for a long time. For example, although the sensor correction is performed according to the first embodiment, the gyro sensor 112 cannot be corrected when the straight movement cannot be detected like a mountain road. Similarly, the sensor correction is performed according to the second embodiment, but the same problem occurs when the vehicle travels on a road extending in a straight line.

  In the above case, the reliability of the detection value of the gyro sensor 112 is lowered. That is, the detection value of the geomagnetic sensor 111 cannot be corrected using the gyro sensor 112. Therefore, the detection value of the geomagnetic sensor 111 is used to correct only the detection value of the gyro sensor. Specifically, the first embodiment is used for straight-ahead determination, and further, the first embodiment is used during straight traveling, and the second embodiment is used during non-straight traveling.

  As described above, the sensor correction apparatus 100 according to the present embodiment may use the function together according to the traveling environment of the moving body 130. Since the sensor correction processing of the first and second embodiments is provided as software, there is no need to change the hardware configuration even when the first and second embodiments are used together, and the advantage is that introduction is easy. It has.

(Configuration example of sensor correction device using a plurality of devices)
Next, a configuration example of a sensor correction device using a plurality of devices will be described. In the first and second embodiments, even if only one of the geomagnetic sensor 111 and the gyro sensor 112 is mounted on the in-vehicle navigation device, the sensor correction is performed by adding a sensor mounted on a mobile phone or the like. Processing can be realized.

  22 and 23 are block diagrams illustrating a configuration example of a sensor correction device using a plurality of devices. FIG. 22 shows the case where the mobile phone 2210 provided with the geomagnetic sensor 111 is communicably connected to the car navigation device 2200 when only the gyro sensor 112 is mounted on the car navigation device 2200. A sensor correction process is realized. Similarly, FIG. 23 shows a sensor according to the present embodiment in which the mobile phone 2310 provided with the gyro sensor 112 is changed to the car navigation device 2300 when only the geomagnetic sensor 111 is mounted on the car navigation device 2300. A correction process is realized.

  When the sensor correction processing is realized by a plurality of devices, a communication function for transmitting and receiving the detected value and the corrected detected value between the devices is required. In the case of FIG. 22, communication between devices is performed by the data reception unit 2201 and the data transmission unit 2202 of the in-vehicle navigation device 2200 and the data transmission unit 2211 and the data reception unit 2212 of the mobile phone 2210. Thereafter, the navigation application 2203 of the in-vehicle navigation device 2200 measures the position of the moving body 130 and displays it on the display unit 2204.

  In the case of FIG. 23, communication between devices is performed by the data transmission unit 2301 and the data reception unit 2302 of the in-vehicle navigation device 2300, and the data reception unit 2311 and the data transmission unit 2312 of the mobile phone 2310. Thereafter, the mobile object 130 is positioned by the navigation application 2313 of the mobile phone 2310 and displayed on the display unit 2303 of the in-vehicle navigation device 2300. Note that the configurations of FIGS. 22 and 23 are examples, and the sensor correction process may be realized by other configurations or three or more devices.

  As described above, according to the sensor correction program, the sensor correction device, and the sensor correction method, a sensor that can obtain an accurate value is determined according to the traveling state of the moving body 130, and the detection value of the sensor is used. Then, the detection value of the other sensor is corrected. Therefore, since the offset error of the detection value of the sensor is canceled autonomously without receiving information from the outside, highly accurate azimuth detection can be supported.

  Further, in the above technique, instead of the gyro sensor 112, if the amount of change in the detection value acquired from the geomagnetic sensor 111 is within a threshold value for a predetermined time or more, it is determined that the moving body is going straight. As a result, it is possible to use the optimal straight-ahead determination process according to the usage environment.

  In addition, the above-described technique further includes an offset of the geomagnetic sensor 111 by providing a function of determining that the moving body is going straight if the detection value acquired from the gyro sensor 112 is within a threshold value for a very short time. The error can be canceled with high accuracy.

  In addition, the above technique further includes a function of calculating the correction value of the detection value of the selected sensor using the amount of change in the detection value of the other sensor that has not been selected, thereby providing an offset error between the two sensors. The accuracy of the detected value can be improved between the sensors.

  Further, in the above technique, when it is determined that the moving body 130 is traveling straight, the detection value of the gyro sensor 112 is selected as a correction target, and the change amount of the detection value of the geomagnetic sensor 111 during a predetermined time is set to zero. The offset error 112 may be calculated. In the case of the configuration as described above, the sensor correction apparatus 100 removes an offset error calculated using the detection value of the geomagnetic sensor 111 from the detection value of the gyro sensor 112, thereby providing a highly accurate detection value without an error. Can be obtained. Therefore, it is possible to automatically correct the error and maintain highly accurate azimuth detection without using the azimuth information from the outside.

  Further, in the above technique, when it is determined that the moving body 130 is not traveling straight, the detection value of the geomagnetic sensor 111 is selected as a correction target, and the change amount and the geomagnetism of the detection value of the gyro sensor 112 in a minute time are selected. The configuration may be such that the offset error of the geomagnetic sensor 111 is calculated using the difference between the detected value of the sensor 111 and the amount of change in a minute time. In the case of the configuration as described above, the sensor correction apparatus 100 removes an offset error calculated using the detection value of the gyro sensor 112 from the detection value of the geomagnetic sensor 111, thereby providing a highly accurate detection value without an error. Can be obtained. Therefore, it is possible to automatically correct the error and maintain highly accurate azimuth detection without using the azimuth information from the outside.

  The technique may further include a function of acquiring a detection value from a newly added sensor. By adopting the above-described configuration, even when only one of the two sensors is mounted on the moving body 130 or when one of the sensors is out of order, the detection value of the added sensor is used. Thus, the sensor correction process can be realized. Therefore, the sensor correction processing according to the present embodiment can be widely used regardless of the configuration of the device mounted on the moving body 130.

  Note that the sensor correction method described in this embodiment can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. The sensor correction program is recorded on a computer-readable recording medium such as a hard disk, a flexible disk, a CD-ROM, an MO, and a DVD, and is executed by being read from the recording medium by the computer. The sensor correction program may be distributed via a network such as the Internet.

  In addition, the sensor correction apparatus 100 described in the present embodiment includes an IC for a specific application such as a standard cell or a structured specific integrated circuit (ASIC) (hereinafter simply referred to as “ASIC”) or a PLD (Programmable) such as an FPGA. It can also be realized by Logic Device). Specifically, for example, the functions of the sensor correction device 100 (straight-line determination unit 401 to acquisition unit 405) are defined by HDL description, and the HDL description is logically synthesized and given to the ASIC or PLD, thereby providing a sensor. The correction device 100 can be manufactured.

  The following additional notes are disclosed with respect to the embodiment described above.

(Supplementary Note 1) A computer that acquires detection values of a geomagnetic sensor and a gyro sensor mounted on a moving body and corrects an offset error included in the detection value,
Rectilinear determination means for determining whether or not the moving body is traveling straight in accordance with whether the amount of change in the detection value of the geomagnetic sensor or the gyro sensor falls below a threshold value;
According to whether or not the moving body is traveling straight by the straight traveling determination means, one of the geomagnetic sensor and the gyro sensor that can obtain an accurate detection value is specified, and the detection value of the other sensor is corrected. Selection means to select,
Correction means for correcting the detection value of the other sensor selected by the selection means using the detection value of the one sensor;
A sensor correction program characterized by functioning as

(Supplementary note 2) The supplementary note 1 is characterized in that if the amount of change in the detected value acquired from the geomagnetic sensor is within a threshold value for a predetermined time or more, the straight traveling judgment means judges that the moving body is going straight. The sensor correction program described in 1.

(Supplementary note 3) The supplementary note 1 is characterized in that the straight traveling determination means determines that the moving body is traveling straight if the detection value acquired from the gyro sensor is within a threshold value for a very short time. The described sensor correction program.

(Supplementary note 4)
Calculation for calculating the correction value of the detection value of the other sensor selected as the correction target by the selection unit using the change amount of the detection value of the one sensor not selected by the selection unit during the predetermined time. Function as a means,
The sensor correction program according to any one of appendices 1 to 3, wherein the correction unit corrects an error in a detection value of the other sensor using the correction value calculated by the calculation unit. .

(Additional remark 5) The said selection means selects the detection value of the said gyro sensor as a correction | amendment object, when the said moving body is discriminate | determining that it is advancing straight by the said rectilinear advance discrimination | determination means,
The calculation means calculates an offset error of the gyro sensor when the detection value of the gyro sensor is selected as a correction target by the selection means, with a change amount of the detection value of the geomagnetic sensor at the predetermined time as zero.
The sensor correction program according to appendix 4, wherein the correction unit corrects an error in a detection value of the gyro sensor using the offset error calculated by the calculation unit as a correction value.

(Appendix 6) When the selection means determines that the moving body is not moving straight, the selection means selects the detection value of the geomagnetic sensor as a correction target,
The calculation means, when the detection value of the geomagnetic sensor is selected as a correction target by the selection means, a change amount of the detection value of the gyro sensor in a minute time and a change amount of the detection value of the geomagnetic sensor in the minute time The offset error of the geomagnetic sensor is calculated using the difference between
6. The sensor correction program according to appendix 4 or 5, wherein the correction unit corrects an error in the detection value of the geomagnetic sensor using the offset error calculated by the calculation unit as a correction value.

(Supplementary note 7)
An acquisition means for acquiring the detection value of the other sensor other than the one sensor provided in the portable device connected to the computer when only the detection value of one of the geomagnetic sensor and the gyro sensor is acquired. Function as
The rectilinear determination means is configured to determine whether the amount of change in the detected value of the other sensor acquired by the acquiring means and the detected value of the one sensor falls below a threshold value. The sensor correction program according to any one of appendices 1 to 6, wherein it is determined whether or not the moving body is traveling straight ahead.

(Appendix 8) A sensor correction device that acquires detection values of a geomagnetic sensor and a gyro sensor mounted on a moving body and corrects an offset error included in the detection value,
Rectilinear determination means for determining whether or not the moving body is traveling straight in accordance with whether the amount of change in the detection value of the geomagnetic sensor or the gyro sensor falls below a threshold value;
According to whether or not the moving body is traveling straight by the straight traveling determination means, one of the geomagnetic sensor and the gyro sensor that can obtain an accurate detection value is specified, and the detection value of the other sensor is corrected. Selecting means to select,
Correction means for correcting the detection value of the other sensor selected by the selection means using the detection value of the one sensor;
A sensor correction apparatus comprising:

(Additional remark 9) The computer which comprises a straight advance discrimination | determination means, a selection means, and a correction | amendment means, acquires the detection value of the geomagnetic sensor and gyro sensor mounted in the moving body, and correct | amends the offset error contained in the said detection value. ,
In the straight-ahead determining means, a straight-ahead determining step of determining whether or not the moving body is traveling straight in accordance with whether the amount of change in the detection value of the geomagnetic sensor or the gyro sensor falls below a threshold value;
In the selection means, the one of the geomagnetic sensor and the gyro sensor that determines an accurate detection value is specified according to whether the moving body is moving straight in the straight traveling determination step, and the other sensors A selection step of selecting a detection value as a correction target;
In the correction means, a correction step of correcting the detection value of the other sensor selected in the selection step using the detection value of the one sensor;
The sensor correction method characterized by performing.

(Supplementary Note 10) When the selection unit determines that the moving body is moving straight by the straight line determination unit, the selection unit selects a detection value of the geomagnetic sensor as a correction target,
The calculation means calculates an offset error of the geomagnetic sensor when the detection value of the geomagnetic sensor is selected as a correction target by the selection means, with the change amount of the detection value of the gyro sensor in the minute time being zero.
The sensor correction program according to appendix 4, wherein the correction unit corrects an error in the detection value of the geomagnetic sensor using the offset error calculated by the calculation unit as a correction value.

(Supplementary Note 11) When the selection unit determines that the moving body is not moving straight by the straight-line determination unit, the selection unit selects a detection value of the gyro sensor as a correction target,
The calculation means, when the detection value of the gyro sensor is selected as a correction target by the selection means, a change amount of the detection value of the geomagnetic sensor in a minute time and a change amount of the detection value of the gyro sensor in the minute time The offset error of the gyro sensor is calculated using the difference between
The sensor correction program according to appendix 4, wherein the correction unit corrects an error in a detection value of the gyro sensor using the offset error calculated by the calculation unit as a correction value.

DESCRIPTION OF SYMBOLS 100 Sensor correction apparatus 101 Selection part 102 Geomagnetic sensor correction value calculation part 103 Gyro sensor correction value calculation part 104 Geomagnetic sensor correction part 105 Gyro sensor correction part 110 Sensor apparatus 111 Geomagnetic sensor 112 Gyro sensor 113 Additional sensor 120 Orientation detection apparatus 130 Moving body (vehicle)
401 Straight traveling discrimination unit 402 Selection unit 403 Calculation unit 404 Correction unit 405 Acquisition unit

Claims (7)

A computer that acquires detection values of a geomagnetic sensor and a gyro sensor mounted on a moving body and corrects an offset error included in the detection value,
Rectilinear determination means for determining whether or not the moving body is traveling straight in accordance with whether the amount of change in the detection value of the geomagnetic sensor or the gyro sensor falls below a threshold value;
According to whether or not the moving body is traveling straight by the straight traveling determination means, one of the geomagnetic sensor and the gyro sensor that can obtain an accurate detection value is specified, and the detection value of the other sensor is corrected. Selection means to select,
Correction means for correcting the detection value of the other sensor selected by the selection means using the detection value of the one sensor;
A sensor correction program characterized by functioning as   2. The straight traveling determination unit according to claim 1, wherein the moving body determines that the moving body is going straight if a change amount of a detection value acquired from the geomagnetic sensor is within a threshold value for a predetermined time or more. Sensor correction program. Said computer further
Calculation for calculating the correction value of the detection value of the other sensor selected as the correction target by the selection unit using the change amount of the detection value of the one sensor not selected by the selection unit during the predetermined time. Function as a means,
The sensor correction program according to claim 1, wherein the correction unit corrects an error in a detection value of the other sensor using the correction value calculated by the calculation unit. The selection means selects the detection value of the gyro sensor as a correction target when the straight moving determination means determines that the moving body is moving straight;
The calculation means calculates an offset error of the gyro sensor when the detection value of the gyro sensor is selected as a correction target by the selection means, with a change amount of the detection value of the geomagnetic sensor at the predetermined time as zero.
The sensor correction program according to claim 3, wherein the correction unit corrects an error of a detection value of the gyro sensor using the offset error calculated by the calculation unit as a correction value. The selection means selects the detection value of the geomagnetic sensor as a correction target when the straight traveling determination means determines that the moving body is not moving straight,
The calculation means, when the detection value of the geomagnetic sensor is selected as a correction target by the selection means, a change amount of the detection value of the gyro sensor in a minute time and a change amount of the detection value of the geomagnetic sensor in the minute time The offset error of the geomagnetic sensor is calculated using the difference between
5. The sensor correction program according to claim 3, wherein the correction unit corrects an error in a detection value of the geomagnetic sensor using the offset error calculated by the calculation unit as a correction value. 6. A sensor correction device that acquires detection values of a geomagnetic sensor and a gyro sensor mounted on a moving body and corrects an offset error included in the detection value,
Rectilinear determination means for determining whether or not the moving body is traveling straight in accordance with whether the amount of change in the detection value of the geomagnetic sensor or the gyro sensor falls below a threshold value;
According to whether or not the moving body is traveling straight by the straight traveling determination means, one of the geomagnetic sensor and the gyro sensor that can obtain an accurate detection value is specified, and the detection value of the other sensor is corrected. Selecting means to select,
Correction means for correcting the detection value of the other sensor selected by the selection means using the detection value of the one sensor;
A sensor correction apparatus comprising: A computer that includes a straight traveling determination unit, a selection unit, and a correction unit, acquires a detection value of a geomagnetic sensor and a gyro sensor mounted on a moving body, and corrects an offset error included in the detection value,
In the straight-ahead determining means, a straight-ahead determining step of determining whether or not the moving body is traveling straight in accordance with whether the amount of change in the detection value of the geomagnetic sensor or the gyro sensor falls below a threshold value;
In the selection means, the one of the geomagnetic sensor and the gyro sensor that determines an accurate detection value is specified according to whether the moving body is moving straight in the straight traveling determination step, and the other sensors A selection step of selecting a detection value as a correction target;
In the correction means, a correction step of correcting the detection value of the other sensor selected in the selection step using the detection value of the one sensor;
The sensor correction method characterized by performing.

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