JP6454857B2 - Posture detection apparatus and posture detection method - Google Patents

Description

  The present invention relates to a posture detection apparatus and a posture detection method for a moving body.

  For example, Patent Document 1 describes a control device for a vehicular lamp that adjusts the optical axis position of the vehicular lamp by automatic leveling control. In order to control the optical axis position of the vehicular lamp, the attitude of the vehicle is detected. In order to detect the vehicle attitude, a triaxial acceleration sensor having an X axis, a Y axis, and a Z axis that are orthogonal to each other is used. The sensor is attached to the vehicle so that the X axis of the sensor is along the longitudinal axis of the vehicle, the Y axis of the sensor is along the horizontal axis of the vehicle, and the Z axis of the sensor is along the vertical axis of the vehicle. Then, the acceleration sensor outputs the numerical value of each component of the acceleration vector in the three-axis directions, and thereby the inclination angle of the vehicle with respect to the horizontal plane is detected. The vehicle inclination angle with respect to the horizontal plane is a total angle of a road surface angle that is an inclination angle of the road surface with respect to the horizontal plane and a vehicle attitude angle that is an inclination angle of the vehicle with respect to the road surface. The control of the optical axis position of the vehicular lamp is presumed that the change in the total angle is a change in the vehicle attitude angle because the road surface angle rarely changes due to the vehicle moving while the vehicle is stopped. Implemented. In addition, the control of the optical axis position of the vehicular lamp while the vehicle is running rarely changes the vehicle attitude angle due to an increase or decrease in the load load or the number of passengers. Presumed to be implemented.

JP 2012-30782 A

  In Patent Document 1, since it is rare that the vehicle attitude angle changes while the vehicle is running, the change in the total angle is estimated to be the change in the road surface angle. However, for a running vehicle, by accelerating / decelerating and turning, the posture change between the front and rear of the vehicle due to the pitching moment, the posture change between the left and right sides of the vehicle due to the rolling moment, and the turning direction of the vehicle due to the yaw moment Changes in posture. For this reason, when the estimation method as described in Patent Document 1 is used, there is a problem that the detection accuracy of the posture of the vehicle is lowered.

  The present invention has been made to solve such problems, and it is an object of the present invention to provide an attitude detection device and an attitude detection method for improving the accuracy of detecting the attitude of a vehicle, that is, a moving body.

  In order to solve the above problems, an attitude detection device according to the present invention is provided in a moving body, and in an attitude detection apparatus that detects the attitude of the moving body, an acceleration sensor that detects linear acceleration along three orthogonal axes. And an angular velocity sensor for detecting angular velocities around three orthogonal axes, and a configuration for receiving the traveling speed data of the moving body and a configuration for receiving detection data from the acceleration sensor and the angular velocity sensor. A calculation unit that calculates the linear velocity using the detected linear acceleration data from the acceleration sensor, with correction using the traveling velocity data and the detected angular velocity data from the angular velocity sensor, The detected angular velocity data from the angular velocity sensor is corrected using the differential velocity that is the difference between the velocity and the traveling velocity data, and the attitude angle of the moving body is calculated.

In the correction using the traveling speed data and the detected angular speed data, the calculation unit may use the differential speed and the centrifugal acceleration of the moving body based on the traveling speed data and the detected angular speed data.
In the correction using the traveling speed data and the detected angular speed data, the calculation unit removes the elements related to the differential speed from the speed obtained by time integration of the acceleration obtained by removing the elements related to the centrifugal acceleration from the detected linear acceleration data. It's okay.
In the correction using the differential velocity, the calculation unit may remove an element related to the angular velocity component of the differential velocity from the detected angular velocity data from the angular velocity sensor.

  Further, the posture detection method according to the present invention is a method for detecting the posture of a moving body, in which the traveling speed data of the moving body, the linear acceleration data of the moving body along the three orthogonal axes, and around the three orthogonal axes The differential velocity, which is the difference between the linear velocity and the traveling velocity data, is obtained by obtaining the angular velocity data of the moving body, calculating the linear velocity using the linear acceleration data, with correction using the traveling velocity data and the angular velocity data. Is used to correct the angular velocity data and calculate the attitude angle of the moving body.

In the correction using the traveling velocity data and the angular velocity data, the differential velocity and the centrifugal acceleration of the moving body based on the traveling velocity data and the angular velocity data may be used.
In the correction using the traveling speed data and the angular speed data, the element related to the differential speed may be removed from the speed obtained by time integration of the acceleration obtained by removing the element related to the centrifugal acceleration from the linear acceleration.
In the correction using the differential velocity, elements relating to the angular velocity component of the differential velocity may be removed from the angular velocity data.

  According to the posture detection device and the posture detection method according to the present invention, it is possible to improve the detection accuracy of the posture of the moving body.

It is the schematic of the attitude | position detection apparatus which concerns on embodiment of this invention. It is a block diagram which shows the structure of the attitude | position detection apparatus of FIG. It is a figure which shows the flow of the attitude | position detection operation | movement by the attitude | position detection apparatus which concerns on embodiment of this invention.

Hereinafter, an attitude detection apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the present embodiment, the posture detection device will be described as being mounted on a vehicle such as an automobile as a moving body.
Referring to FIGS. 1 and 2 together, an attitude detection device 100 mounted on a vehicle (not shown) includes a substrate 2, a calculation unit 3 configured by a CPU circuit mounted on the substrate 2, and the substrate 2. The three-axis gyro sensor 10 mounted on the substrate 2 and the three-axis acceleration sensor 20 mounted on the substrate 2 are included as one detection unit 1. In the present embodiment, detection unit 1 is fixed to the vehicle with substrate 2 in a state parallel to the vehicle floor (not shown), that is, in a state parallel to the ground on which the vehicle is located. Here, the three-axis gyro sensor 10 constitutes an angular velocity sensor.
Further, posture detection apparatus 100 includes a vehicle speed sensor 4 provided outside detection unit 1. The vehicle speed sensor 4 may be provided individually for the posture detection device 100 or may be a vehicle speed sensor provided as a standard in a vehicle (not shown). The calculation unit 3 is configured to receive vehicle speed information detected by the vehicle speed sensor 4.

  The three-axis gyro sensor 10 includes an X-axis angular velocity detection unit 11, a Y-axis angular velocity detection unit 12, and a Z-axis angular velocity detection unit 13. The X axis is a direction along the front-rear direction of the vehicle (not shown) and along the surface of the substrate 2. The Y axis is a direction along the left-right direction of the vehicle (not shown) and along the surface of the substrate 2. The Z axis is a direction along the vertical direction of the vehicle (not shown) and perpendicular to the surface of the substrate 2. The X axis, the Y axis, and the Z axis are orthogonal to each other. Therefore, the X-axis angular velocity detection unit 11 detects a roll angular velocity that is a change speed of the vehicle roll angle around the X-axis. The Y-axis angular velocity detection unit 12 detects a pitching angular velocity that is a changing speed of the vehicle pitching angle around the Y-axis. The Z-axis surrounding angular velocity detection unit 13 detects a yaw angular velocity that is a changing speed of the yaw angle of the vehicle around the Z-axis. The calculation unit 3 is configured to receive information on the roll angular velocity, the pitching angular velocity, and the yaw angular velocity of the vehicle detected by the three-axis gyro sensor 10.

  The triaxial acceleration sensor 20 includes an X axis direction acceleration detection unit 21, a Y axis direction acceleration detection unit 22, and a Z axis direction acceleration detection unit 23. The X-axis direction acceleration detection unit 21 detects a linear acceleration in the longitudinal direction of the vehicle (not shown) along the X-axis. The Y-axis direction acceleration detection unit 22 detects the linear acceleration in the left-right direction of the vehicle along the Y-axis. The Z-axis direction acceleration detection unit 23 detects the linear acceleration in the vertical direction of the vehicle along the Z-axis. The calculation unit 3 is configured to receive information on the vehicle longitudinal linear acceleration, the lateral linear acceleration, and the vertical linear acceleration detected by the triaxial acceleration sensor 20.

Next, the posture detection operation of the vehicle by the posture detection apparatus 100 will be described.
2 and 3 together, the calculation unit 3 continuously receives the linear acceleration α continuously received from the triaxial acceleration sensor 20, the angular velocity ω continuously received from the triaxial gyro sensor 10, and the vehicle speed sensor 4. The vehicle attitude angle is continuously calculated using the vehicle speed ν received automatically.

  In the process of continuously calculating the attitude angle of the vehicle, the calculation unit 3 uses the already calculated attitude angle θ of the vehicle to convert the linear acceleration α received from the triaxial acceleration sensor 20 into two orthogonal directions parallel to the horizontal plane. Coordinate conversion is performed into a three-dimensional coordinate system having an axis and one axis perpendicular to the horizontal plane.

Specifically, the linear acceleration α includes α _X , α _Y, and α _Z as X-axis, Y-axis, and Z-axis components. α _X and α _Y are axial components parallel to the substrate 2, and α _Z is an axial component perpendicular to the substrate 2.
Then, by performing coordinate transformation using the components α _X , α _Y and α _Z and the components θ _X , θ _Y and θ _{Z of} the posture angle θ, the linear acceleration α is converted into the components α _{X ′} , α _{Y ′} and α _The linear acceleration α ′ having _{Z ′} is obtained.
The components θ _X , θ _Y, and θ _Z are components of posture angles with respect to the X axis, the Y axis, and the Z axis, respectively. Further, the component α _{X ′} is a component of the _{X ′} axis obtained by projecting the X axis onto the horizontal plane, and the component α _{Y ′} is a Y ′ axis perpendicular to the X ′ axis on the same horizontal plane as the X ′ axis. The component α _{Z ′} is a component of the Z ′ axis in the vertical direction that is perpendicular to the X ′ axis and the Y ′ axis.

Next, the calculation unit 3 obtains the linear velocity V of the vehicle.
At this time, with respect to the linear acceleration α ′ (α _{X ′} , α _{Y ′} , α _{Z ′} ), the effect of acceleration / deceleration resulting from the acceleration / deceleration of the traveling of the vehicle, the turning traveling of the vehicle, and the uphill / downhill traveling The linear velocity is calculated by time-integrating the linear acceleration from which each influence has been removed. Further, the calculated linear speed is compared with the vehicle speed, and the calculated linear speed is corrected based on the error between them, and the corrected linear speed is set as the linear speed V to be obtained.

  Specifically, the calculation unit 3 combines an influence of acceleration / deceleration acceleration caused by acceleration / deceleration of traveling of the vehicle and an influence of centrifugal acceleration caused by turning / uphill / downhill traveling of the vehicle, This is obtained from the centrifugal acceleration G calculated using the angular velocity ω and the vehicle speed ν received from the three-axis gyro sensor 10.

The angular velocity ω includes ω _X , ω _Y, and ω _Z as components in the angular directions around the X axis, the Y axis, and the Z axis. The vehicle speed ν includes ν _X , ν _Y, and ν _Z as X-axis, Y-axis, and Z-axis components, and ν _Y and ν _Z are zero. Centrifugal acceleration G is, XY plane including the X-axis and Y-axis, YZ plane including the Y-axis and Z-axis, as well as an acceleration component along each ZX plane including the Z-axis and _X-axis, G _{XY, G YZ} and Includes G _ZX .

Therefore, the acceleration components G _XY , G _YZ and G _ZX are as follows.
G _XY = (ν _X ² + ν _Y ² ) ^1/2 ω _Z = ν _X ω _Z
G _YZ = (ν _Y ² + ν _Z ² ) ^1/2 ω _X = 0
G _ZX = (ν _Z ² + ν _X ² ) ^1/2 ω _Y = ν _X ω _Y

Further, the calculation unit 3 converts the centrifugal acceleration G (G _XY , G _YZ , G _ZX ) into a coordinate system composed of the X ′ axis, the Y ′ axis, and the Z ′ axis, and converts the centrifugal acceleration G ′ (G _{X 'Y'} , _{GY'Z '} , _GZ'X' ). G _{X′Y ′} , G _{Y′Z ′} and G _{Z′X ′} are acceleration components along the X′Y ′ plane, the Y′Z ′ plane, and the Z′X ′ plane, respectively.
Therefore, when calculating the linear velocity V, the calculation unit 3 calculates the centrifugal acceleration G ′ (G _{X′Y ′} , G _{Y′Z ′} ) from the linear acceleration α ′ (α _{X ′} , α _{Y ′} , α _{Z ′} ). _{GZ'X '} ) is reduced, that is, centrifugal acceleration correction is performed.

The corrected linear acceleration α ′ _A (α _{AX ′} , α _{AY ′} , α _{AZ ′} ) after the centrifugal acceleration correction is obtained as follows.
α _{AX ′} = α _{X ′} − (G _{X′Y ′} ² + G _{Z′X ′} ² ) ^1/2
α _{AY ′} = α _{Y ′} − ( _{GX′Y ′} ² + G _{Y′Z ′} ² ) ^1/2
α _{AZ ′} = α _{Z ′} − (G _{Y′Z ′} ² + G _{Z′X ′} ² ) ^1/2 −g
Note that g is a gravitational acceleration.

Further, the calculation unit 3 integrates each component of the corrected linear acceleration α ′ _A (α _{AX ′} , α _{AY ′} , α _{AZ ′} ) with time, and a speed V 1 that is a linear speed before correction of the target linear speed V. (V1 _{X ′} , V1 _{Y ′} , V1 _{Z ′} ) is calculated.

Next, the calculation unit 3 performs coordinate conversion of the vehicle speed ν (ν _X , ν _Y , ν _Z ) into a coordinate system composed of the X ′ axis, the Y ′ axis, and the Z ′ axis, and the vehicle speed ν ′ (ν _{X ′} , (ν _{Y ′} , ν _{Z ′} ) is obtained.
Then, the calculation unit 3 calculates a differential speed Vda ′ (which is a difference between the linear speed V1a before correction corresponding to the linear speed at the time point before the linear speed V to be calculated and the vehicle speed ν ′ at the time point. Vda _{X ′} , Vda _{Y ′} , Vda _{Z ′} ) are obtained.

The calculation unit 3 performs correction for subtracting the difference speed Vda to obtain the linear speed V with respect to the linear speed V1 before correction corresponding to the linear speed V to be calculated, that is, performs correction speed calculation. At this time, the linear velocity V (V _{X ′} , V _{Y ′} , V _{Z ′} ) is as follows.
_{V X '= V1 X' -Vda} X '× K1
_{V Y '= V1 Y' -Vda} Y '× K1
VZ _′ = V1 _Z′− Vda _{Z ′} × K1
K1 is a constant, and is set as appropriate according to various factors such as the performance of the 3-axis gyro sensor 10, the performance of the 3-axis acceleration sensor 20, the performance of the vehicle speed sensor 4, and the mounting position of the detection unit 1. Is done.
Therefore, the linear velocity V of the vehicle is influenced by the acceleration / deceleration acceleration caused by the acceleration / deceleration of the vehicle traveling, the influence of the centrifugal acceleration caused by the vehicle turning traveling and the uphill / downhill traveling, and the calculated linear velocity The influence of the error between the vehicle speed and the vehicle speed is eliminated, which is required. That is, the linear velocity V has high accuracy.

In addition, the calculation unit 3 calculates a difference speed Vd ′ (Vd _{X ′} , Vd _{Y ′} , Vd _{Z ′)} that is a difference between the calculated linear speed V and the vehicle speed ν ′ at the time corresponding to the time of the linear speed V. ) The differential speed Vd ′ (Vd _{X ′} , Vd _{Y ′} , Vd _{Z ′} ) is as follows.
Vd _{X ′} = V _{X ′} −ν _{X ′}
Vd _{Y ′} = V _{Y ′} −ν _{Y ′}
Vd _{Z ′} = V _{Z ′} −ν _{Z ′}

Next, the calculation unit 3 performs coordinate conversion of the differential speed Vd ′ into a coordinate system composed of the X axis, the Y axis, and the Z axis to obtain a differential speed Vd (Vd _X , Vd _Y , Vd _Z ), and further, the differential speed A differential angular velocity ωd composed of angular velocity components ωd _X , ωd _Y , and ωd _Z around the X axis, around the Y axis, and around the Z axis is calculated from Vd. The differential angular velocity ωd (ωd _X , ωd _Y , ωd _Z ) is as follows. Note that r is a constant and is determined according to the configuration of the three-axis gyro sensor 10.
ωd _X = (Vd _Y ² + Vd _Z ² ) ^1/2 / r
ωd _Y = (Vd _X ² + Vd _Z ² ) ^1/2 / r
ωd _Z = (Vd _X ² + Vd _Y ² ) ^1/2 / r

Then, the arithmetic unit 3, performing the angular velocity omega received from the triaxial gyro sensor _{10 (ω X, ω Y,} ω Z) difference angular velocity .omega.d from each component of _{(ωd X, ωd Y, ωd} Z) the corrected angular velocity calculation reduces the Thus, the corrected angular velocity ωa (ωa _X , ωa _Y , ωa _Z ) is calculated. Each angular velocity component of the corrected angular velocity ωa is as follows.
ωa _X = ω _X −K2 × ωd _X
ωa _Y = ω _Y −K2 × ωd _Y
ωa _Z = ω _Z −K2 × ωd _Z
K2 is a constant, and is set as appropriate according to various factors such as the performance of the 3-axis gyro sensor 10, the performance of the 3-axis acceleration sensor 20, the performance of the vehicle speed sensor 4, and the mounting position of the detection unit 1. Is done.
Therefore, the corrected angular velocity ωa (ωa _X , ωa _Y , ωa _Z ) is an error generated when the velocity is calculated using only the three-axis gyro sensor 10 and the three-axis acceleration sensor 20, that is, the three-axis gyro sensor 10 The influence of the error generated in the result calculated using only the three-axis acceleration sensor 20 is excluded with respect to the angular velocity ω (ω _X , ω _Y , ω _Z ).

Further, the calculation unit 3 performs quaternion integration including time integration on the corrected angular velocity ωa (ωa _X , ωa _Y , ωa _Z ), and the X axis and Y axis of the attitude angle θ of the vehicle (not shown), that is, the detection unit 1. And direction cosines cos θ _X , cos θ _Y and cos θ _Z with respect to the Z axis are calculated. Based on the calculated direction cosines cos θ _X , cos θ _Y, and cos θ _Z , the calculation unit 3 calculates the angle components θ _X , θ _Y, and θ _Z of the posture angle θ with respect to the X axis, the Y axis, and the Z axis, and the posture The amount of change and the posture angle are obtained.

  As described above, the attitude detection device 100 according to the embodiment of the present invention is provided in a vehicle and detects the attitude of the vehicle, and detects three linear axes along three orthogonal axes. The acceleration sensor 20, the three-axis gyro sensor 10 that detects angular velocities around three orthogonal axes, and the vehicle speed data that is the traveling speed data of the vehicle, and the three-axis acceleration sensor 20 and the three-axis gyro sensor 10 And a calculation unit 3 that calculates the attitude of the vehicle. The calculation unit 3 calculates the linear velocity using the detected linear acceleration data from the triaxial acceleration sensor 20 with correction using the vehicle speed data and the detected angular velocity data from the triaxial gyro sensor 10, and calculates the linear velocity and The detected angular velocity data from the three-axis gyro sensor 10 is corrected using the differential speed, which is the difference from the vehicle speed data, to calculate the attitude angle of the vehicle. Further, in the correction using the vehicle speed data and the detected angular velocity data, the calculation unit 3 uses the difference speed and the centrifugal acceleration of the vehicle based on the vehicle speed data and the detected angular velocity data.

  In the above configuration, the calculation unit 3 performs correction using the vehicle speed data and the detected angular velocity data from the three-axis gyro sensor 10 when calculating the linear velocity from the detected linear acceleration data from the three-axis acceleration sensor 20. That is, the correction using the element related to the actual traveling speed of the vehicle and the element related to the centrifugal acceleration of the vehicle is performed. Thereby, in the calculated linear speed, the difference with respect to the actual traveling speed of the vehicle can be corrected, and the influence related to the centrifugal acceleration of the vehicle can be eliminated. Further, by correcting using the differential speed, the corrected detected angular speed data can eliminate an error with respect to the actual angular speed related to the difference with respect to the actual traveling speed of the vehicle. Therefore, it becomes possible to detect the attitude angle of the vehicle with high accuracy.

In the posture detection device 100, the calculation unit 3 corrects the acceleration obtained by time-integrating the acceleration obtained by removing the element related to the centrifugal acceleration from the detected angular velocity data in the correction using the vehicle speed data and the detected angular velocity data. Remove elements related to differential speed. As a result, it is possible to easily perform a correction calculation that provides a highly accurate result.
In the posture detection apparatus 100, the calculation unit 3 removes an element related to the angular velocity component of the differential velocity from the detected angular velocity data in the correction using the differential velocity. This makes it possible to easily perform correction using the differential speed that gives a highly accurate result.

Moreover, in the attitude | position detection apparatus 100 which concerns on embodiment, although the calculating part 3 performed the correction | amendment angular velocity calculation using the difference speed of the linear speed and vehicle speed after correction speed calculation implementation, it is limited to this. Not a thing. The calculation unit 3 may use the difference speed between the linear speed before correction and the vehicle speed for calculating the correction angular speed.
Further, in posture detection apparatus 100 according to the embodiment, calculation unit 3 includes time integration with respect to a component obtained by subtracting differential angular velocity ωd from each component of angular velocity ω received from triaxial gyro sensor 10 with respect to correction angular velocity calculation. Although quaternion integration has been performed, it is not limited to this. The calculation unit 3 may calculate the posture angle of the vehicle from the direction cosine of each posture angle after performing quaternion integration including time integration individually on the angular velocity ω and the differential angular velocity ωd.

In the posture detection apparatus 100 according to the embodiment, the calculation unit 3 performs coordinate conversion between the coordinate system based on the XYZ axes and the coordinate system based on the X′Y′Z ′ axes. The calculation may be performed using only the coordinate system based on the XYZ axes without performing the above.
In the posture detection device 100 according to the embodiment, the three-axis gyro sensor 10 and the three-axis acceleration sensor 20 share the same X-axis, Y-axis, and Z-axis. The axis and the Z axis may be different. In this case, the calculation unit 3 may perform coordinate conversion of the detection data with respect to one of the triaxial gyro sensor 10 and the triaxial acceleration sensor 20 at the time of calculation.
Moreover, although the attitude | position detection apparatus 100 which concerns on embodiment was mounted in the vehicle, you may mount in any mobile body.

  DESCRIPTION OF SYMBOLS 1 Detection unit, 3 calculating part, 4 vehicle speed sensor, 10 3 axis gyro sensor (angular velocity sensor), 20 3 axis acceleration sensor, 100 attitude | position detection apparatus.

Claims (8)

In an attitude detection device that is provided on a moving body and detects the attitude of the moving body,
An acceleration sensor that detects linear acceleration along three orthogonal axes;
An angular velocity sensor for detecting angular velocities around three orthogonal axes;
A calculation unit configured to receive the traveling speed data of the moving body and configured to receive detection data from the acceleration sensor and the angular velocity sensor;
The computing unit is
A linear velocity is calculated using the detected linear acceleration data from the acceleration sensor, with correction using the traveling velocity data and the detected angular velocity data from the angular velocity sensor,
An attitude detection device that corrects detected angular velocity data from the angular velocity sensor and calculates an attitude angle of the moving body using a difference velocity that is a difference between the linear velocity and the traveling velocity data.   The calculation unit uses the differential speed and the centrifugal acceleration of the moving body based on the traveling speed data and the detected angular velocity data in the correction using the traveling speed data and the detected angular velocity data. The attitude detection device described.   In the correction using the traveling speed data and the detected angular velocity data, the calculation unit is configured to calculate the difference with respect to a speed obtained by time-integrating an acceleration obtained by removing elements related to the centrifugal acceleration from the detected linear acceleration data. The posture detection apparatus according to claim 2, wherein an element related to speed is removed.   The posture detection according to any one of claims 1 to 3, wherein in the correction using the differential velocity, the calculation unit removes an element related to an angular velocity component of the differential velocity from detection angular velocity data from the angular velocity sensor. apparatus. In a method for detecting the posture of a moving object,
Obtaining the moving speed data of the moving body, linear acceleration data of the moving body along three orthogonal axes, and angular velocity data of the moving body around the three orthogonal axes;
With a correction using the traveling speed data and the angular speed data, a linear speed is calculated using the linear acceleration data,
A method of calculating the attitude angle of the moving body by correcting the angular velocity data using a difference velocity which is a difference between the linear velocity and the traveling velocity data.   The method according to claim 5, wherein the correction using the traveling speed data and the angular speed data uses the differential speed and the centrifugal acceleration of the moving body based on the traveling speed data and the angular speed data.   The correction using the traveling speed data and the angular speed data removes an element related to the differential speed from a speed obtained by time integration of an acceleration obtained by removing an element related to the centrifugal acceleration from the linear acceleration. 6. The method according to 6.   The method according to claim 5, wherein in the correction using the differential velocity, an element related to an angular velocity component of the differential velocity is removed from the angular velocity data.

Images