Arithmetic processing method, arithmetic processing program, and arithmetic processing device

Abstract

To reduce error in comparison with the case of using only a correction coefficient to correct output of a direction change sensor.SOLUTION: An arithmetic processing method makes a computer execute the steps of: calculating a correction coefficient for correcting an output of a direction change sensor for detecting a direction change in a vehicle's horizontal plane, according to the vehicle's attitude angle relative to the horizontal plane corresponding to an output from an attitude angle sensor; calculating a correction term to correct the output of the direction change sensor according to changes in the attitude angle; and correcting the output of the direction change sensor using the correction coefficient and the correction term.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a processing method, a processing program, and a processing device. [Background technology]

[0002] Patent Document 1 states, "When the gradient angle, i.e., the dynamic change angle, is β [°], the detection axis X is inclined by β [°] with respect to the detection axis X' during horizontal traveling, and therefore the detection axis X is inclined by α + β [°] with respect to the vertical axis V. Therefore, the output J of the gyro sensor 4 is multiplied by cos(α + β), or Jcos(α + β). In this case, the amount of change in orientation indicated in the gyro information generated from the output Jcos(α + β) of the gyro sensor 4 is also multiplied by cos(α + β). Meanwhile, as described above, the static correction coefficient Ds is calculated by multiplying the basic correction coefficient Db by cos α. Therefore, by multiplying the static correction coefficient Ds by (1 / cos α) to remove the influence of the installation angle α [°], and then multiplying the result by cos(α + β) and setting the result as the dynamic correction coefficient Da, the gyro information can be appropriately corrected according to dynamic changes in the detection axis X direction of the gyro sensor 4." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-155365 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in the conventional technology disclosed in Patent Document 1, gyro information is corrected by multiplying it by a correction coefficient. However, when correction is performed using only the correction coefficient, an error may occur in the calculation of the amount of change in azimuth.

[0005] The present disclosure has been made in consideration of the above points, and aims to provide a method, a program, and an apparatus that can reduce errors compared to when the output of an orientation change sensor is corrected using only a correction coefficient. [Means for solving the problem]

[0006] A first aspect of the arithmetic processing method includes the steps of: calculating, by a computer, a correction coefficient for correcting the output of an orientation change sensor for detecting an orientation change in a horizontal plane of the vehicle, based on an attitude angle of the vehicle relative to the horizontal plane corresponding to an output of an attitude angle sensor; calculating a correction term for correcting the output of the orientation change sensor, based on the change in the attitude angle; and correcting the output of the orientation change sensor using the correction coefficient and the correction term.

[0007] In the arithmetic processing method of the first aspect, even when the correction coefficient alone is insufficient to perform a correction calculation for the output of the orientation change sensor, the output of the orientation change sensor is corrected by taking into account not only the correction coefficient but also the correction term. As a result, the arithmetic processing method of the first aspect can provide a method that can further reduce errors compared to when the output of the orientation change sensor is corrected using only the correction coefficient. Therefore, the arithmetic processing method of the first aspect can provide a method that also contributes to more accurate detection of the current position of a vehicle using dead reckoning.

[0008] In a second aspect of the arithmetic processing method, in the first aspect, the attitude angle includes a pitch angle and a roll angle, and calculating the correction term includes calculating the correction term by multiplying a change in the pitch angle by a sine of the roll angle.

[0009] In the second aspect of the arithmetic processing method, the fluctuation of the attitude angle is captured along two axes, the roll direction and the pitch direction, and a correction term is calculated by multiplying the change in the pitch angle by the sine of the roll angle. As a result, the second aspect of the arithmetic processing method can reduce the occurrence of errors even when the pitch direction tilt changes while there is tilt in the roll direction.

[0010] In the arithmetic processing method of a third aspect, in the arithmetic processing method of the second aspect, calculating the correction coefficient includes calculating the correction coefficient using the reciprocal of the product of the cosine of the pitch angle and the cosine of the roll angle.

[0011] In the calculation processing method of the third aspect, the change in the attitude angle is captured along two axes, the roll angle and the pitch angle, and a correction coefficient is calculated as the reciprocal of the product of the cosine of the pitch angle and the cosine of the roll angle. As a result, the calculation processing method of the third aspect can reduce the occurrence of errors even when the pitch angle changes while there is a tilt in the roll direction.

[0012] A fourth aspect of the arithmetic processing method is the arithmetic processing method of the third aspect, wherein correcting the output of the orientation change sensor includes adding the correction term to the output of the orientation change sensor and multiplying the result by the correction coefficient.

[0013] In the fourth aspect of the arithmetic processing method, when correcting the output of the orientation change sensor, a correction term is added in addition to multiplication by a correction coefficient. As a result, according to the fourth aspect of the arithmetic processing method, by simply adding a relatively simple calculation, it is possible to reduce errors that cannot be corrected by the correction coefficient alone.

[0014] A arithmetic processing method of a fifth aspect is the arithmetic processing method of the fourth aspect, wherein correcting the output of the orientation change sensor includes correcting the output of the orientation change sensor by the following equation, where ψ' is the orientation change per unit time, R is the output of the orientation change sensor, θ is the pitch angle, θ' is the change in pitch angle per unit time, and φ is the roll angle.

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[0015] In the fifth aspect of the arithmetic processing method, the output of the orientation change sensor is corrected using a formula calculated based on the three-dimensional equation of motion, thereby making it possible to rationally correct the output of the orientation change sensor in accordance with the laws of motion in physics.

[0016] A sixth aspect of the arithmetic processing program causes a computer to execute the following processes: calculating a correction coefficient for correcting the output of an orientation change sensor for detecting an orientation change in a horizontal plane of the vehicle, based on an attitude angle of the vehicle with respect to the horizontal plane corresponding to the output of an attitude angle sensor; calculating a correction term for correcting the output of the orientation change sensor, based on the change in the attitude angle; and correcting the output of the orientation change sensor using the correction coefficient and the correction term.

[0017] In the arithmetic processing program of the sixth aspect, even when the correction coefficient alone is insufficient to correct the output of the heading change sensor, the output of the heading change sensor is corrected by taking into account not only the correction coefficient but also the correction term. As a result, the arithmetic processing program of the sixth aspect can provide a program that can further reduce errors compared to when the output of the heading change sensor is corrected using only the correction coefficient. Therefore, the arithmetic processing program of the sixth aspect can provide a program that also contributes to more accurate detection of the current position of a vehicle using dead reckoning.

[0018] A seventh aspect of the arithmetic processing device includes a processor, wherein the processor calculates a correction coefficient for correcting the output of an orientation change sensor for detecting an orientation change in the horizontal plane of the vehicle based on an attitude angle of the vehicle relative to the horizontal plane corresponding to the output of an attitude angle sensor, calculates a correction term for correcting the output of the orientation change sensor based on the change in the attitude angle, and corrects the output of the orientation change sensor using the correction coefficient and the correction term.

[0019] In the seventh aspect of the arithmetic processing device, even when the correction coefficient alone is insufficient to correct the output of the heading change sensor, the output of the heading change sensor is corrected by taking into account not only the correction coefficient but also the correction term. As a result, the seventh aspect of the arithmetic processing device can provide a device that can further reduce errors compared to when the output of the heading change sensor is corrected using only the correction coefficient. Therefore, the seventh aspect of the arithmetic processing device can provide a device that also contributes to more accurate detection of the current position of a vehicle using dead reckoning. [Effects of the Invention]

[0020] According to the present disclosure, errors can be reduced compared to when the output of the orientation change sensor is corrected using only the correction coefficient. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 2 is a diagram illustrating an example of a definition of a vehicle coordinate system. [Figure 2] FIG. 2 is a diagram illustrating an example of a definition of a vehicle body attitude angle. [Figure 3] 1 is a diagram illustrating an example of a hardware configuration of a processing device 100 according to the present embodiment. [Figure 4] 1 is a diagram illustrating an example of a functional configuration of a processing device 100 according to the present embodiment. [Figure 5] FIG. 2 is a diagram showing an example of the flow of arithmetic processing executed by the arithmetic processing device 100 according to the present embodiment. [Figure 6] FIG. 2 is a diagram illustrating an example of a functional configuration of a processing device 100′ according to a comparative example. [Figure 7] FIG. 2 is a diagram showing an example of a travel course. [Figure 8] FIG. 10 is a diagram showing an example of an azimuth angle error caused by a processing device 100′ according to a comparative example. [Figure 9] FIG. 4 is a diagram showing an example of an azimuth angle error caused by the arithmetic processing device 100 according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] An example of an embodiment of the present disclosure will be described below with reference to the drawings. In each drawing, the same or equivalent components and parts are designated by the same reference numerals. Furthermore, the dimensional proportions in the drawings are exaggerated for the sake of explanation and may differ from the actual proportions.

[0023] 1 is a diagram showing an example of the definition of a vehicle coordinate system. The vehicle coordinate system may be defined by three mutually orthogonal axes, for example, an X-axis, a Y-axis, and a Z-axis. In this diagram, an example is shown in which the X-axis is defined as the forward direction of the vehicle 10, the Y-axis is defined as the right direction of the vehicle 10, and the Z-axis is defined as the downward direction of the vehicle 10.

[0024] This diagram also shows an example in which the velocity of the vehicle 10 is defined as (U, V, W), where U is the X-axis component of the velocity, V is the Y-axis component of the velocity, and W is the Z-axis component of the velocity. This diagram also shows an example in which the angular velocity of the vehicle 10 is defined as (P, Q, R), where P is the roll rate, Q is the pitch rate, and R is the yaw rate.

[0025] 2 is a diagram showing an example of the definition of a vehicle body attitude angle. The vehicle body attitude angle may be defined by three angles: a roll angle φ, a pitch angle θ, and a yaw angle ψ. In this diagram, as an example, the roll angle φ is defined as the angle at which the X-axis rotates clockwise with respect to a case where the vehicle 10 is horizontal (i.e., the angle at which the vehicle body rotates downward and to the right around the X-axis), the pitch angle θ is defined as the angle at which the Y-axis rotates clockwise with respect to a case where the vehicle 10 is horizontal (i.e., the angle at which the vehicle body rotates upward and to the front around the Y-axis), and the yaw angle (also referred to as an azimuth angle) ψ is defined as the angle at which the Z-axis rotates clockwise with respect to a case where the vehicle 10 is horizontal (i.e., the angle at which the vehicle body rotates clockwise around the Z-axis).

[0026] In such a case, the amount of change in orientation in the horizontal plane while the vehicle 10 is traveling can be calculated by installing an angular velocity sensor on the vehicle 10 so that its axis of rotation is vertical, i.e., by making it function as a yaw rate gyro, and integrating the angular velocity output from the sensor over time.

[0027] However, if the rotation axis of the gyro is tilted from the vertical, an error will occur in the calculation of the amount of change in orientation in the horizontal plane. Note that the tilt of the rotation axis here is not only the tilt when the gyro is installed on the vehicle 10, but also fluctuates due to the influence of the gradient of the road on which the vehicle is traveling and the tilt of the vehicle body caused by the driving conditions (longitudinal acceleration due to acceleration / deceleration, centrifugal force when turning, etc.).

[0028] In conventional technology, the angle at which the gyro's rotation axis is tilted from the vertical direction is detected by a gradient sensor, and an appropriate correction coefficient is calculated when calculating the amount of change in heading to reduce errors in the amount of change in heading. However, it was found that the following two problems remain with the conventional technology.

[0029] First, the conventional technology does not correctly calculate the tilt from the vertical direction when the attitude angle changes. In the conventional technology, the equations in the examples do not hold unless the angles α and β are on the same plane. However, the diagrams in the examples only show the tilt in the pitch angle direction due to the installation angle and longitudinal gradient, and do not take into account the case where the tilt in the roll direction is also included.

[0030] The second problem is that, in the conventional technology, when the tilt in the pitch direction changes while there is tilt in the roll direction, an error component that cannot be corrected by the correction coefficient alone occurs in the calculation of the amount of change in heading. Generally, roads have a cross gradient, i.e., a cant angle, due to issues such as drainage, and therefore the condition in which the tilt in the pitch direction changes while there is tilt in the roll direction is a driving condition that is quite likely to occur when the vehicle 10 travels on an actual road.

[0031] Therefore, the calculation processing device 100 according to this embodiment aims to improve the correction calculation to solve this problem, thereby obtaining the amount of change in orientation with higher accuracy. This will be described in detail.

[0032] 3 is a diagram showing an example of the hardware configuration of a processing device 100 according to this embodiment. The processing device 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a storage 104, a communication interface 105, a user interface 106, an orientation change sensor 107, and an attitude angle sensor 108. These components are connected to each other via a bus 109 so as to be able to communicate with each other.

[0033] Note that this diagram is an example of a hardware configuration, and the arithmetic processing device 100 is not necessarily limited to this configuration. The arithmetic processing device 100 may not include some of the configuration shown in this diagram, or may further include other configurations not shown in this diagram (for example, a GPS module, a vehicle speed sensor, etc.). The same applies to the other diagrams.

[0034] The CPU 101 is a central processing unit that executes various programs and controls each component. The ROM 102 stores various programs and various data. The RAM 103 temporarily stores programs or data as a working area. The storage 104 is composed of an HDD (Hard Disk Drive) or SSD (Solid State Drive) and stores various programs including the operating system and various data.

[0035] In the arithmetic processing device 100 according to this embodiment, an arithmetic processing program is stored in the ROM 102 or the storage 104. The CPU 101 reads the arithmetic processing program from the ROM 102 or the storage 104, and executes it using the RAM 103 as a working area, thereby controlling each component and executing various arithmetic processing in accordance with the arithmetic processing program.

[0036] The communication interface 105 is an interface for the processor 100 to communicate with other devices. The user interface 106 is an input / output interface for the processor 100 to exchange information with a user.

[0037] The heading change sensor 107 is a sensor for detecting a change in heading in the horizontal plane of the vehicle 10. As described above, the heading change sensor 107 may be an angular velocity sensor that functions as a yaw rate gyro.

[0038] The attitude angle sensor 108 is a sensor for detecting the attitude angle of the vehicle 10 with respect to a horizontal plane. The attitude angle sensor 108 may be a two-axis acceleration sensor, and the pitch angle θ and the roll angle φ may be estimated from the gravity component detected by the acceleration sensor.

[0039] While the diagram shows an example in which the heading change sensor 107 and the attitude angle sensor 108 are provided inside the arithmetic processing device 100, it is sufficient that the heading change sensor 107 and the attitude angle sensor 108 are provided in the vehicle 10, and at least one of the heading change sensor 107 and the attitude angle sensor 108 may be provided outside the arithmetic processing device 100. In this case, the arithmetic processing device 100 may acquire the output of the heading change sensor 107 and the output of the attitude angle sensor 108 via the communication interface 105.

[0040] 4 is a diagram showing an example of the functional configuration of the arithmetic processing device 100 according to this embodiment. The arithmetic processing device 100 includes an orientation change sensor output acquisition unit 110, an attitude angle sensor output acquisition unit 120, an attitude angle estimation unit 130, a correction coefficient calculation unit 140, a correction term calculation unit 150, and a correction unit 160. These functional configurations may be realized by the CPU 101 reading out an arithmetic processing program from the ROM 102 or the storage 104, expanding it in the RAM 103, and executing it.

[0041] The heading change sensor output acquisition unit 110 acquires the output of the heading change sensor 107 provided on the vehicle 10 to detect a change in heading of the vehicle 10 in the horizontal plane.

[0042] The attitude angle sensor output acquisition unit 120 acquires the output of the attitude angle sensor 108 provided on the vehicle 10 to detect the attitude angle of the vehicle 10 with respect to the horizontal plane.

[0043] The attitude angle estimation unit 130 estimates the attitude angles of the vehicle 10 with respect to the horizontal plane, here the pitch angle θ and the roll angle φ, from the output of the attitude angle sensor 108.

[0044] The correction coefficient calculation unit 140 calculates a correction coefficient for correcting the output of the orientation change sensor 107 based on the attitude angle of the vehicle 10 relative to the horizontal plane, which corresponds to the output of the attitude angle sensor 108.

[0045] The correction term calculation unit 150 calculates a correction term for correcting the output of the orientation change sensor 107 based on the change in the attitude angle of the vehicle 10 relative to the horizontal plane according to the output of the attitude angle sensor 108 .

[0046] The correction unit 160 uses a correction coefficient and a correction term to correct the output of the orientation change sensor 107. More specifically, the correction unit 160 may correct the output of the orientation change sensor 107 using the following equation, where ψ' is the orientation change per unit time, R is the output of the orientation change sensor 107 (i.e., yaw rate), θ is the pitch angle, θ' is the change in pitch angle per unit time, and φ is the roll angle. The reason for this will be explained in detail below.

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[0047] The relationship between the yaw rate gyro and azimuth change is derived based on the three-dimensional equation of motion of a rigid body. For example, assume that three-axis angular velocities, i.e., roll rate P, pitch rate Q, and yaw rate R, can be obtained using an inertial sensor installed on the vehicle 10. In this case, the change in attitude angle of the vehicle 10 can be expressed by the following equation, using the above definition and assuming that φ' is the change in roll angle per unit time.

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[0048] Here, by extracting the third equation from equation (2), the following equation can be obtained to find the azimuth change ψ' per unit time.

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[0049] However, a yaw rate gyro and a pitch rate gyro are required to calculate equation 3. Therefore, in order to find the azimuth change ψ' per unit time using only the yaw rate gyro, the pitch rate Q is eliminated from equation 3 using the second equation of equation 2, leading to equation 1.

[0050] According to equation (1), it can be seen that the correction coefficient alone may not be sufficient to correct the yaw rate R to the change in heading ψ' per unit time in the horizontal plane of the vehicle 10, and a correction term may be necessary. Therefore, the arithmetic processing device 100 according to this embodiment calculates a correction term in addition to the correction coefficient, and attempts to correct the yaw rate R, i.e., the output R of the heading change sensor 107, using the correction coefficient and the correction term.

[0051] The arithmetic processing executed by the arithmetic processing device 100 having such a functional configuration will be described in detail using a flow chart.

[0052] 5 is a diagram showing an example of the flow of arithmetic processing executed by the arithmetic processing device 100 according to this embodiment. This flow may be executed by the CPU 101 reading out the arithmetic processing program from the ROM 102 or the storage 104, expanding it in the RAM 103, and executing it.

[0053] In step S210, CPU 101 functions as orientation change sensor output acquisition unit 110 to acquire output R of orientation change sensor 107 provided on vehicle 10 to detect orientation change of vehicle 10 in the horizontal plane.

[0054] In step S220, the CPU 101 functions as the attitude angle sensor output acquisition unit 120 to acquire the output of the attitude angle sensor 108 provided on the vehicle 10 to detect the attitude angle of the vehicle 10 with respect to the horizontal plane.

[0055] In step S230, CPU 101, as attitude angle estimation unit 130, estimates the attitude angle of the vehicle with respect to the horizontal plane from the output of attitude angle sensor 108 acquired in step S220. For example, CPU 101 may estimate pitch angle θ and roll angle φ from the gravity component detected by attitude angle sensor 108, which is a two-axis acceleration sensor.

[0056] When the vehicle 10 is stationary, the CPU 101 can estimate the pitch angle θ and the roll angle φ using only the acceleration sensor. However, when the vehicle 10 is moving, translational acceleration occurs during the movement. In such a case, the CPU 101 can separately estimate the attitude angle by combining information such as wheel speed. As a specific method for estimating the attitude angle can be any of various existing methods, a detailed description thereof will be omitted here.

[0057] In step S240, the CPU 101, functioning as the correction coefficient calculation unit 140, calculates a correction coefficient based on the attitude angle estimated in step S230. For example, the CPU 101 may calculate 1 / (cos θ·cos φ) in equation 1 as the correction coefficient. In this way, for example, the CPU 101 may calculate the correction coefficient as the reciprocal of the product of the cosine of the pitch angle θ and the cosine of the roll angle φ.

[0058] In step S250, CPU 101, functioning as correction term calculation unit 150, calculates a correction term based on the amount of change in attitude angle estimated in step S230. For example, CPU 101 may calculate θ' sin φ in equation (1) as the correction term. In this case, CPU 101 may obtain the change θ' in pitch angle per unit time as a difference from the previous value, or may obtain it by averaging multiple samples. In this way, CPU 101 may calculate the correction term as the product of the change θ' in pitch angle per unit time and the sine of the roll angle φ.

[0059] In step S260, CPU 101, functioning as correction unit 160, corrects output R of orientation change sensor 107 acquired in step S210 using the correction coefficient calculated in step S240 and the correction term calculated in step S250. For example, CPU 101 may correct output R of the orientation change sensor using the above-mentioned equation (Equation 1). CPU 101 may correct output R of the orientation change sensor by adding correction term θ' sin φ to output R of orientation change sensor 107 and multiplying it by correction coefficient 1 / (cos θ cos φ) in this way, for example.

[0060] Note that CPU 101 may change the order of calculations for correction as appropriate as long as it follows equation 1. For example, CPU 101 may multiply output R of orientation change sensor 107 by a correction coefficient, and then add the value obtained by multiplying the correction term by the correction coefficient as the correction value.

[0061] After that, the CPU 101 can obtain the amount of change in orientation in the horizontal plane by time-integrating the corrected yaw rate. If the attitude angle changes while traveling, the CPU 101 can use the attitude angle information at each time when performing the time integration.

[0062] 6 is a diagram showing an example of the functional configuration of a processing device 100' according to a comparative example. In this figure, the same configurations or elements as those in FIG. 4 are denoted by the same reference numerals, and descriptions thereof will be omitted hereinafter except for differences. The processing device 100' according to the comparative example does not include a correction term calculation unit 150. Therefore, in the processing device 100' according to the comparative example, the correction unit 160' corrects the output R of the orientation change sensor 107 using only a correction coefficient without using a correction term.

[0063] Note that correcting the output R of the orientation change sensor 107 using only the correction coefficient corresponds to omitting the second term in the numerator in equation (1) and approximating it with the following equation: This corresponds to the case where the correction coefficient is the reciprocal of the cosine of the angle α that the rotation axis of the yaw rate gyro makes with the vertical direction.

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[0064] In the conventional technology disclosed in Patent Document 1, when the tilt α is changed by an angle β, the angle formed with the vertical direction is considered to be α+β. However, if the tilt directions are different (for example, if the tilt α is in the roll angle direction and the angle change β is in the pitch angle direction), the angle formed with the vertical direction after the angle change will not be α+β.

[0065] In this way, the effect of correcting the output of the orientation change sensor 107 using both the correction coefficient and the correction term will be demonstrated by simulation, compared to correcting the output of the orientation change sensor 107 using only the correction coefficient.

[0066] In the simulation, typical driving conditions are set for cases where the heading change cannot be calculated correctly using the correction coefficient alone. On ordinary roads, a cross gradient, i.e., a cant angle, is set due to issues such as drainage. As specified in the Road Structure Ordinance, the cross gradient is usually between -1.5% and 2%. Therefore, when traveling straight on an undulating road surface with a cant angle, the heading of the vehicle 10 remains constant, but only the pitch angle fluctuates. It is assumed that the pitch angle of the vehicle 10 fluctuates along the longitudinal gradient of the road surface.

[0067] Fig. 7 is a diagram showing an example of a travel course. In this diagram, the horizontal axis represents travel distance [m], and the vertical axis represents height [m]. As shown in this diagram, the travel course is divided into four sections: Section A, where the travel distance is up to 0m, Section B, where the travel distance is 0m to 180m, Section C, where the travel distance is 180m to 360m, and Section D, where the travel distance is 360m or more.

[0068] Here, the entire driving course, i.e., Sections A, B, C, and D, have a road surface cant angle of -2% (-0.02 rad). Furthermore, Sections A and D have a longitudinal gradient of 0%, Section B has a longitudinal gradient of 5% (= 0.05 rad, approximately 2.86 degrees), and Section C has a longitudinal gradient of -5% (= -0.05 rad, approximately -2.86 degrees). Note that the area 5 m before and after the point where the longitudinal gradient changes is designated as a gradient transition section.

[0069] A simulation was performed on such a traveling course, with the horizontal speed set to a constant, here 10 m / s, and assuming that there were no sensor errors or attitude angle errors in order to compare the presence or absence of a correction term.

[0070] 8 is a diagram showing an example of an azimuth angle error calculated by the arithmetic processing device 100' according to the comparative example. In this diagram, the horizontal axis represents the travel distance [m], and the vertical axis represents the azimuth angle error [deg]. As shown in this diagram, when the correction calculation by the arithmetic processing device 100' according to the comparative example is performed, that is, when the output of the azimuth change sensor 107 is corrected using only the correction coefficient without using the correction term, an azimuth angle error of just under 0.06 degrees occurs at the point where the longitudinal gradient changes.

[0071] The magnitude of this azimuth angle error is equivalent to a lateral position error of approximately 1 m occurring when traveling 1 km using dead reckoning. If the change in longitudinal gradient exceeds the conditions used in the simulation, the azimuth angle error will increase further. Therefore, when considering maintaining lane accuracy, even this kind of error may not be negligible.

[0072] 9 is a diagram showing an example of an azimuth angle error calculated by the processing device 100 according to this embodiment. The definitions of the axes are the same as those in FIG. 8, and therefore will not be described here. As shown in this diagram, when the processing device 100 according to this embodiment performs a correction calculation, that is, when the output of the azimuth change sensor 107 is corrected using both the correction coefficient and the correction term, no azimuth angle error occurs even at points where the longitudinal gradient changes.

[0073] As described above, the simulation also revealed that the arithmetic processing device 100 according to this embodiment can reduce azimuth angle errors compared to when the output of the azimuth change sensor 107 is corrected using only a correction coefficient without using a correction term. Therefore, it can be said that the arithmetic processing device 100 according to this embodiment is also effective in reducing position errors in dead reckoning navigation.

[0074] In the above embodiments, the arithmetic processing performed by the CPU after reading the software (program) may be performed by various processors other than the CPU. Examples of such processors include programmable logic devices (PLDs) such as field-programmable gate arrays (FPGAs), whose circuit configuration can be changed after fabrication, and application-specific integrated circuits (ASICs), which are dedicated electrical circuits that are processors with circuit configurations specifically designed to perform specific processing. The arithmetic processing may be performed by one of these various processors, or by a combination of two or more processors of the same or different types (e.g., multiple FPGAs, or a combination of a CPU and an FPGA). The hardware structure of these various processors is, more specifically, an electrical circuit that combines circuit elements such as semiconductor devices.

[0075] In addition, in each of the above embodiments, the arithmetic processing program is described as being pre-stored (installed) in the ROM 102 or the storage 104, but the present invention is not limited to this. The program may be provided in a form stored in a non-transitory storage medium such as a CD-ROM (Compact Disk Read Only Memory), a DVD-ROM (Digital Versatile Disk Read Only Memory), or a USB (Universal Serial Bus) memory. The program may also be downloaded from an external device via a network.

[0076] All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

[0077] This disclosure also includes the following:

[0078] (Appendix 1) The computer calculating a correction coefficient for correcting an output of a direction change sensor for detecting a change in the direction of the vehicle in the horizontal plane based on an attitude angle of the vehicle relative to the horizontal plane according to an output of the attitude angle sensor; calculating a correction term for correcting an output of the orientation change sensor based on the change in the attitude angle; correcting an output of the orientation change sensor using the correction coefficient and the correction term; A calculation processing method comprising: (Appendix 2) the attitude angle includes a pitch angle and a roll angle, calculating the correction term includes calculating the correction term by a product of the change in the pitch angle and a sine of the roll angle; 10. The calculation method according to claim 1. (Appendix 3) calculating the correction coefficient includes calculating the correction coefficient using the inverse of the product of the cosine of the pitch angle and the cosine of the roll angle; 3. The arithmetic processing method according to claim 1 or 2. (Appendix 4) correcting the output of the orientation change sensor includes adding the correction term to the output of the orientation change sensor and multiplying the result by the correction coefficient. 4. A calculation method according to any one of claims 1 to 3. (Appendix 5) correcting the output of the orientation change sensor includes correcting the output of the orientation change sensor by the following equation, where ψ' is the orientation change per unit time, R is the output of the orientation change sensor, θ is the pitch angle, θ' is the change in pitch angle per unit time, and φ is the roll angle:

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[0079] 10 vehicles 100 Processing unit 101 CPU 102 ROM 103 RAM 104 Storage 105 Communication Interface 106 User Interface 107 Orientation change sensor 108 Attitude Angle Sensor 109 Bus 110 Orientation change sensor output acquisition unit 120 Attitude angle sensor output acquisition unit 130 Attitude angle estimation section 140 Correction coefficient calculation unit 150 Correction term calculation unit 160 Correction unit

Claims

1. The computer calculating a correction coefficient for correcting an output of a direction change sensor for detecting a change in the direction of the vehicle in the horizontal plane based on an attitude angle of the vehicle relative to the horizontal plane according to an output of the attitude angle sensor; calculating a correction term for correcting an output of the orientation change sensor based on the change in the attitude angle; correcting an output of the orientation change sensor using the correction coefficient and the correction term; A computational processing method comprising:

2. the attitude angle includes a pitch angle and a roll angle, calculating the correction term includes calculating the correction term by a product of the change in the pitch angle and a sine of the roll angle; The arithmetic processing method according to claim 1 .

3. calculating the correction coefficient includes calculating the correction coefficient using the inverse of the product of the cosine of the pitch angle and the cosine of the roll angle; The arithmetic processing method according to claim 2 .

4. correcting the output of the orientation change sensor includes adding the correction term to the output of the orientation change sensor and multiplying the result by the correction coefficient. The arithmetic processing method according to claim 3.

5. Correcting the output of the orientation change sensor includes correcting the output of the orientation change sensor by the following equation, where ψ' is the orientation change per unit time, R is the output of the orientation change sensor, θ is the pitch angle, θ' is the change in pitch angle per unit time, and φ is the roll angle: [Equation 1] The arithmetic processing method according to claim 4.

6. On the computer, a process of calculating a correction coefficient for correcting an output of a direction change sensor for detecting a change in the direction of the vehicle in the horizontal plane, based on an attitude angle of the vehicle relative to the horizontal plane according to an output of the attitude angle sensor; a process of calculating a correction term for correcting an output of the orientation change sensor based on the change in the attitude angle; a process of correcting an output of the orientation change sensor using the correction coefficient and the correction term; A computational processing program that executes the above.

7. a processor, the processor comprising: calculating a correction coefficient for correcting the output of a direction change sensor for detecting a change in the direction of the vehicle in the horizontal plane based on the attitude angle of the vehicle relative to the horizontal plane according to the output of the attitude angle sensor; calculating a correction term for correcting the output of the orientation change sensor based on the change in the attitude angle; correcting the output of the orientation change sensor using the correction coefficient and the correction term; Processing unit.

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