JP5511088B2 - Portable device, program and method for correcting gravity vector used for autonomous positioning - Google Patents

Description

  The present invention relates to a technique for correcting a gravity vector used for autonomous positioning.

  Conventionally, there is a technique for correcting a gravity vector in order to estimate an accurate terminal posture (see, for example, Patent Document 1). According to this technique, the portable device has an angular velocity sensor and an acceleration sensor, and sequentially calculates the direction of gravity from the angular velocity data and the acceleration data. The gravity vector is calculated based on the angular velocity data. First, the gravity vector is corrected so as to approach the direction of the acceleration vector. Next, when the terminal performs a predetermined motion, the gravity vector is corrected so as to approach the direction of gravity estimated from the predefined relationship between the acceleration data and the angular velocity data. Finally, the gravity vector is corrected so as to approach the average direction of the acceleration vector in a predetermined period. An accurate terminal posture can be estimated using the gravity vector corrected in this way.

JP 2010-263930 A

  According to the technique described in Patent Document 1, it is necessary to mount at least an angular velocity sensor on a portable device. Moreover, it is necessary to define the relationship between acceleration data and angular velocity data in advance, and it is not possible to cope with individual differences in the manner of holding the portable device.

  Accordingly, an object of the present invention is to provide a portable device, a program, and a method that can correct a gravity vector regardless of individual differences in the manner of holding the portable device.

According to the present invention,
An acceleration sensor that outputs triaxial acceleration data;
A geomagnetic sensor that outputs triaxial geomagnetic data;
A mobile device for calculating a gravity vector using acceleration data and geomagnetic data, and having an autonomous positioning means for outputting an estimated azimuth angle d autonomously measured, and estimating the gravity vector,
Estimated azimuth angle buffer means for accumulating an estimated azimuth angle d during circumferential movement of the device based on user behavior;
Coordinate difference deriving after circumference movement of the device, startup position north-south direction coordinate difference obtained by accumulating the change in coordinates of each estimated azimuth d to the end turned position from N (Σcosd) and east-west direction coordinate difference E a (Σsind) Deriving means;
Pitch offset calculating means for calculating the pitch offset p based on the north-south direction coordinate difference N, and / or roll offset calculating means for calculating the roll offset r based on the east-west direction coordinate difference E,
The autonomous positioning means calculates the estimated azimuth angle d using the gravity vector corrected by the pitch offset p and / or the roll offset r.

φ：所定の地磁気ベクトルから重力ベクトルに対する伏角
ｄ：１歩毎の推定方位角
θ：円周移動によって得られるｄの変化を０〜２πの連続的変化に近似した方位角
当該ピッチオフセットテーブルを用いて、当該南北方向座標差Ｎから、ピッチオフセットｐを導出するものであり、
ロールオフセット算出手段は、東西方向座標差Ｅと、ロールオフセットｒとが、以下の式を満たすように対応付けられたロールオフセットテーブルを有し、

当該ロールオフセットテーブルを用いて、当該東西方向座標差Ｅから、ロールオフセットｒを導出することも好ましい。 According to another embodiment of the portable device of the present invention,
The pitch offset calculating means includes a pitch offset table in which the north-south direction coordinate difference N and the pitch offset p are associated with each other so as to satisfy the following expression:

φ: Depression angle from a predetermined geomagnetic vector to the gravity vector d: Estimated azimuth angle for each step θ: Azimuth angle obtained by approximating a change of d obtained by circumferential movement to a continuous change of 0 to 2π Using the pitch offset table The pitch offset p is derived from the north-south direction coordinate difference N,
The roll offset calculation means has a roll offset table in which the east-west coordinate difference E and the roll offset r are associated with each other so as to satisfy the following expression:

It is also preferable to derive the roll offset r from the east-west direction coordinate difference E using the roll offset table.

According to another embodiment of the portable device of the present invention,
A circumferential movement period detecting means for detecting a circumferential movement period in which the estimated azimuth angle d varies from 0 ° to 360 °;
The estimated azimuth angle buffer means also preferably stores the estimated azimuth angle d during the circumferential movement period .

According to the present invention,
An acceleration sensor that outputs triaxial acceleration data;
A geomagnetic sensor that outputs triaxial geomagnetic data;
A computer mounted on a portable device having a function,
A program for estimating a gravity vector, which calculates a gravity vector using acceleration data and geomagnetic data, and causes a computer to function as an autonomous positioning means for outputting an estimated azimuth angle d autonomously measured,
Estimated azimuth angle buffer means for accumulating an estimated azimuth angle d during circumferential movement of the device based on user behavior;
Coordinate difference deriving after circumference movement of the device, startup position north-south direction coordinate difference obtained by accumulating the change in coordinates of each estimated azimuth d to the end turned position from N (Σcosd) and east-west direction coordinate difference E a (Σsind) Deriving means;
Pitch offset calculating means for calculating the pitch offset p based on the north-south direction coordinate difference N, and / or roll offset calculating means for calculating the roll offset r based on the east-west direction coordinate difference E,
The autonomous positioning means further causes the computer to function so as to calculate the estimated azimuth angle d using the gravity vector corrected by the pitch offset p and / or the roll offset r.

φ：所定の地磁気ベクトルから重力ベクトルに対する伏角
ｄ：１歩毎の推定方位角
θ：円周移動によって得られるｄの変化を０〜２πの連続的変化に近似した方位角
当該ピッチオフセットテーブルを用いて、当該南北方向座標差Ｎから、ピッチオフセットｐを導出するものであり、
ロールオフセット算出手段は、東西方向座標差Ｅと、ロールオフセットｒとが、以下の式を満たすように対応付けられたロールオフセットテーブルを有し、

当該ロールオフセットテーブルを用いて、当該東西方向座標差Ｅから、ロールオフセットｒを導出する
ようにコンピュータを機能させることも好ましい。 According to another embodiment of the program for the portable device of the present invention,
The pitch offset calculating means includes a pitch offset table in which the north-south direction coordinate difference N and the pitch offset p are associated with each other so as to satisfy the following expression:

φ: Depression angle from a predetermined geomagnetic vector to the gravity vector d: Estimated azimuth angle for each step θ: Azimuth angle obtained by approximating a change of d obtained by circumferential movement to a continuous change of 0 to 2π Using the pitch offset table The pitch offset p is derived from the north-south direction coordinate difference N,
The roll offset calculation means has a roll offset table in which the east-west coordinate difference E and the roll offset r are associated with each other so as to satisfy the following expression:

It is also preferable to make the computer function so as to derive the roll offset r from the east-west direction coordinate difference E using the roll offset table.

According to another embodiment of the program for the portable device of the present invention,
A circumferential movement period detecting means for detecting a circumferential movement period in which the estimated azimuth angle d varies from 0 ° to 360 °;
The estimated azimuth angle buffer means preferably causes the computer to further function so as to accumulate the estimated azimuth angle d during the circumferential movement period .

According to the present invention,
An acceleration sensor that outputs triaxial acceleration data;
A geomagnetic sensor that outputs triaxial geomagnetic data;
A method of correcting a gravity vector for a portable device having an autonomous positioning function that calculates an estimated azimuth angle d autonomously determined while calculating a gravity vector using acceleration data and geomagnetic data,
During circumferential movement of the device based on user behavior, and storing the estimated azimuth angle d, was after circumferential movement of the apparatus, the coordinate variation for each estimated azimuth angle d from startup position to a final turned position accumulated South A first step of deriving a directional coordinate difference N (Σcosd) and an east-west coordinate difference E (Σsind) ;
Calculating a pitch offset p based on the north-south direction coordinate difference N and / or calculating a roll offset r based on the east-west direction coordinate difference E;
The autonomous positioning function includes a third step of calculating the estimated azimuth angle d using the gravity vector corrected by the pitch offset p and / or the roll offset r.

φ：所定の地磁気ベクトルから重力ベクトルに対する伏角
ｄ：１歩毎の推定方位角
θ：円周移動によって得られるｄの変化を０〜２πの連続的変化に近似した方位角
当該ピッチオフセットテーブルを用いて、当該南北方向座標差Ｎから、ピッチオフセットｐを導出し、
ロールオフセットｒの算出には、東西方向座標差Ｅと、ロールオフセットｒとが、以下の式を満たすように対応付けられたロールオフセットテーブルを有し、

当該ロールオフセットテーブルを用いて、当該東西方向座標差Ｅから、ロールオフセットｒを導出する
ようにコンピュータを機能させることも好ましい。 According to another embodiment of the gravity vector correction method of the present invention,
The calculation of the pitch offset p has a pitch offset table in which the north-south direction coordinate difference N and the pitch offset p are associated with each other so as to satisfy the following equation:

φ: Depression angle from a predetermined geomagnetic vector to the gravity vector d: Estimated azimuth angle for each step θ: Azimuth angle obtained by approximating a change of d obtained by circumferential movement to a continuous change of 0 to 2π Using the pitch offset table The pitch offset p is derived from the north-south direction coordinate difference N,
In calculating the roll offset r, there is a roll offset table in which the east-west coordinate difference E and the roll offset r are associated so as to satisfy the following formula:

It is also preferable to make the computer function so as to derive the roll offset r from the east-west direction coordinate difference E using the roll offset table.

According to another embodiment of the gravity vector correction method of the present invention,
For the first step, it is also preferable to detect a circumferential movement period in which the estimated azimuth angle d changes from 0 ° to 360 ° and accumulate the estimated azimuth angle d in the circumferential movement period .

  According to the portable device, program and method of the present invention, by calculating the pitch offset and / or roll offset from the geomagnetic data and the estimated azimuth obtained by the circumferential movement of the user, by correcting the gravity vector by the offset, The accuracy of autonomous positioning can be improved regardless of individual differences in the manner in which the portable device is held.

It is a functional block diagram of the portable apparatus in this invention. It is explanatory drawing showing the circumference movement of the user who possesses the said portable apparatus. It is a user coordinate system representing the relationship between the gravity vector G and the geomagnetic vector M.

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

  FIG. 1 is a functional configuration diagram of a portable device according to the present invention.

  The mobile device 1 is possessed by a user and is, for example, a mobile phone or a smartphone. According to FIG. 1, the mobile device 1 includes an acceleration sensor 101 and a geomagnetic sensor 102.

  The acceleration sensor 101 detects a change in acceleration, that is, a speed per unit time. In the case of the three-axis type that can detect the tilt of the portable device, three-dimensional acceleration can be detected, and the measurement of the earth's gravity (static acceleration) can be supported.

  The geomagnetic sensor 102 measures the direction of geomagnetism in three axial directions (front-rear direction, left-right direction, and up-down direction). The geomagnetic sensor 102 separates the Hall elements and outputs values detected from the separated Hall elements.

  In addition, the mobile device 1 includes an autonomous positioning unit 111, a coordinate difference deriving unit 112, a circumferential movement period detecting unit 113, an estimated azimuth angle buffer unit 114, a pitch offset calculating unit 115, and a roll offset calculating unit 116. And an application unit 117. The application unit 117 provides various services to the user using the estimated azimuth angle d derived from the autonomous positioning unit 111. These functional components are realized by executing a program that causes a computer mounted on the mobile device 1 to function. The processing flow of these functional components can also be understood as a gravity vector correction method.

  The autonomous positioning unit 111 calculates a gravity vector using acceleration data and geomagnetic data, and outputs an estimated azimuth angle d (°) measured autonomously. The autonomous positioning unit 111 is based on the existing dead reckoning (DR) technology (autonomous dead reckoning navigation technology), and even if it is in a place where it cannot receive positioning radio waves, such as indoors, its position is autonomous. You can measure the position. The dead reckoning technology is a relative self-position estimation technology using an encoder or inertial sensor, and generally adds geomagnetic data or angular velocity data (gyroscope) and acceleration data to known initial values (position and orientation). In addition, the subsequent position and orientation are calculated. Therefore, errors are accumulated only with the dead reckoning technology. That is, the gravitational vector error is also accumulated.

According to FIG. 1, the autonomous positioning unit 111 receives the pitch offset p from the pitch offset calculation unit 115 and the roll offset r from the roll offset calculation unit 116. Here, it is assumed that the moving direction is the x-axis positive direction, the left hand direction with respect to the moving direction is the y-axis positive direction, and the upper direction with respect to the moving direction is the z-axis direction. At this time, the rotation of each axis is expressed as follows.
Rotation around the x axis: roll
Rotation around y-axis: pitch
Rotation around the z axis: yaw

  The autonomous positioning unit 111 adds the pitch offset p to the estimated azimuth angle calculated by itself (back calculation), and adds the roll offset r to the gravity vector calculated by itself (back calculation). Thereby, the error of the gravity vector in autonomous positioning can be corrected, and the accuracy of subsequent autonomous positioning can be improved.

  FIG. 2 is an explanatory diagram showing the circumferential movement of the user who possesses the portable device.

  As shown in FIG. 2, the portable device 1 instructs the user to make one round in the circumferential direction so that the start position and the end position coincide with each other. Here, when an error is included in the gravity vector calculated by the autonomous positioning unit 111 itself, an error also occurs in the estimated azimuth angle d output from the autonomous positioning unit 111. This causes an error that the start position coordinates and the end position coordinates do not match. That is, the movement trajectory is deformed by the error of the gravity vector in the autonomous positioning unit 111. The gravity vector includes an error between the pitch offset and the roll offset.

  “Pitch offset” is a rotation offset of the gravity vector with the horizontal direction as the rotation axis. The “roll offset” is a rotation offset of the gravity vector with the front-rear direction as the rotation axis. Here, when moving (walking) in a single direction and trying to correct the gravity vector from the geomagnetic data and acceleration data, the following problems occur.

(1) The pitch offset and the roll offset cannot be separated.
(2) It is necessary to acquire the absolute azimuth | direction in a movement from GPS (Global Positioning System).

  On the other hand, according to the present invention, the user possessing the portable device 1 only moves (walks) in a circle around the circumference and draws a circle, and does not require GPS.

  The coordinate difference deriving unit 112 calculates the north-south direction coordinate difference N and the east-west direction coordinate difference E from the coordinate difference between the start position and the end position when the device makes one round in the circumferential direction based on the user's action. To derive.

From the coordinate difference, the offset is calculated backward by subsequent processing. Note the following points.
(1) When walking in a circle, no pitch offset is applied to the east-west coordinate difference E. In other words, it is offset to zero.
(2) When walking in a circle, no roll offset is applied to the north-south direction coordinate difference N. In other words, it is offset to zero.

  Thus, since the absolute azimuth is not required by moving once in the circumferential direction, there is no need to mount an absolute positioning unit such as GPS. The user holding the portable terminal only has to walk in a circle and return to the starting position, and does not need to be aware of the direction.

  According to another embodiment of the present invention, the circumferential movement period detection unit 113 may be further provided. The circumferential movement period detection unit 113 detects that the user is circling from the change in the estimated azimuth angle. It is detected that the estimated azimuth angle changes from 0 ° to 360 °.

  Corresponding to the circumferential movement period detection unit 113, an estimated azimuth angle buffer unit 114 is further provided. The estimated azimuth angle buffer unit 114 accumulates a plurality of estimated azimuth angles d output from the autonomous positioning unit 111 during the circumferential movement period, and outputs these estimated azimuth angles to the circumferential movement period detection unit 113. The estimated azimuth angle may be acquired, for example, for each number of steps in the circumferential movement period.

  In the circumferential movement period, the user himself / herself inputs “circumferential movement start” to the mobile terminal, makes a round in the circumferential direction, and then inputs “circumferential movement end” to the mobile terminal. There may be. In this case, it is not necessary to mount the circumferential movement period detection unit 113 and the estimated azimuth angle buffer unit 114 on the portable device.

  FIG. 3 shows a user coordinate system representing the relationship between the gravity vector G and the geomagnetic vector M.

  FIG. 3 shows the moving azimuth angle θ estimated by the gravity vector G. Further, with respect to the gravity vector G, the geomagnetic vector M has an dip angle φ. Here, the dip angle φ is constant even if there is a one-way movement in the circumferential direction by the mobile terminal.

  The geomagnetism has come from the south to the north, and the geomagnetic vector is a vector indicating the north (magnetic north) direction with a specific dip angle φ depending on the region. A projection vector onto a plane (ground surface) perpendicular to the gravity vector G represents a north-facing vector. The rotation angle θ from the north vector to the forward vector represents the moving direction azimuth. The angle is expressed clockwise from north.

According to FIG. 3, the geomagnetic vector is decomposed into a front-rear component, a rotation axis component, and a vertical component.
Front and rear component = sinφcosθ
Rotational axis component = sinφsinθ
Vertical component = cosφ

  By applying an offset to the gravity vector, the geomagnetic vector appears to rotate from its original position in the coordinate system based on the gravity vector. If this is seen from a plane (ground surface) perpendicular to the gravity vector, the north direction appears to deviate from the correct position. At this time, θ is the observed azimuth angle d.

[Pitch offset calculation unit 115]
The pitch offset calculation unit 115 calculates the pitch offset p based on the north-south direction coordinate difference N between the start position and the end position of the user. Here, the north-south direction coordinate difference N is represented by FIG. The pitch offset calculation unit 115 has a pitch offset table that stores the pitch offset p in association with the north-south direction coordinate difference N.

Here, consider a case where a pitch offset p is applied to the geomagnetic vector. The rotation axis component of the geomagnetic vector is constant because it is not affected by rotation.
Rotational axis component = sinφsinθ

On the other hand, the rotation surface component (front-rear component, vertical component) is expressed as follows.
m = (sinφcosθ, cosφ)
When rotation p (pitch offset) is added to this, the result is as follows.

That is, the front and rear components (observed values) to which the pitch offset is applied are expressed as follows.
Front and rear component = sinφcosθcosp−cosφsinp

The coordinates of the estimated azimuth angle d when one step is taken are expressed as follows.
(E, N) = (e ₁ , n ₁ ) = (sind ₁ , cosd ₁ )

E and N are expressed by the equations of θ and p as follows depending on the rotation surface component and the front and rear components described above.

Here, consider the coordinates when the user walks X and walks once in a clockwise direction from an azimuth angle of 0 °. The coordinates in the east-west direction are expressed as follows by the above formula.

  According to this equation, an odd function is obtained, and E = 0. This means that the pitch offset p is not applied.

In addition, the north-south direction coordinates are expressed as follows by the above formula.

  According to this formula, the north-south coordinate N and the pitch offset p can be related. The pitch offset table stores in advance the north-south coordinate N and the pitch offset p in association with each other. Of course, according to the present invention, the above-described formula may be calculated in real time, but it is preferable that the formula is registered in advance in the table because a load is imposed on the calculation processing amount.

[Roll offset calculation unit 116]
The roll offset calculation unit 116 calculates the roll offset r based on the east-west coordinate difference E between the start position and the end position of the user. Here, the east-west direction coordinate difference E is represented by FIG. The roll offset calculation unit 116 has a roll offset table that stores the roll offset r in association with the east-west direction coordinate difference E.

Here, consider a case where a roll offset r is applied to the geomagnetic vector. The front and rear components of the geomagnetic vector are constant because they are not affected by rotation.
Rotational axis component = sinφcosθ

On the other hand, the rotation plane component (horizontal component, vertical component) is expressed as follows.
m = (sinφsinθ, cosφ)
If rotation r (pitch offset) is added to this, the result is as follows.

That is, the horizontal component (observed value) to which the roll offset is applied is expressed as follows.
Horizontal component = sinφsinθcosr−cosφsinr

The coordinates of the estimated azimuth angle d when one step is taken are expressed as follows.
(E, N) = (e ₁ , n ₁ ) = (sind ₁ , cosd ₁ )

E and N are represented by the equations of θ and r as follows by the rotation surface component and the horizontal component described above.

Here, consider the coordinates when the user walks X and walks once in a clockwise direction from an azimuth angle of 0 °. The coordinates in the east-west direction are expressed as follows by the above formula.

  According to this equation, the east-west coordinate E and the roll offset r can be related. The roll offset table stores in advance the east-west coordinate E and the roll offset r in association with each other. Of course, according to the present invention, the above-described formula may be calculated in real time, but it is preferable that the formula is registered in advance in the table because a load is imposed on the calculation processing amount.

In addition, the north-south direction coordinates are expressed as follows by the above formula.

  According to this equation, an odd function is obtained, and N = 0. This means that the roll offset r is not applied.

As described above, the coordinates after walking once have the following characteristics.
North-south direction: only the pitch offset p is reflected East-west direction: only the roll offset r is reflected Thereby, the pitch offset and the roll offset can be derived from the coordinates after the pedestrian makes a round.

  The pitch offset p and / or roll offset r calculated in this way is fed back to the autonomous positioning unit 111. As a result, the autonomous positioning unit 111 estimates a position using a vector obtained by subtracting the pitch offset p from the gravity vector estimated by itself as a gravity vector.

  Finally, the relational expression between the north-south direction coordinate difference N and the pitch offset p and the relational expression between the east-west direction coordinate difference E and the roll offset r will be supplementarily described.

  “Θ” in the equation means “legitimate azimuth”. Here, according to the present invention, it is not necessary to directly observe the valid direction θ. The legitimate azimuth is considered to have changed continuously, for example, θ = 0 °, 1 °, 2 °,..., 359 ° by turning the portable device once in the circumferential direction. It is. According to the present invention, after making one round in the circumferential direction, the pitch offset and the roll offset can be calculated backward from the coordinate difference.

  Here, the coordinate difference that appears as a positional deviation is a result of accumulation of the estimated position obtained from the estimated azimuth angle d when moving (walking) while changing the valid azimuth angle θ. Therefore, according to the above formula, the east-west coordinate difference E and the north-south coordinate difference N are represented by the integral of the valid azimuth angle θ (change from 0 to 2π) with the pitch offset p and the roll offset r. The In this equation, the values that can be observed in advance (known values to be input) are only the dip angle φ (fixed value) of the geomagnetic vector, the north-south direction coordinate difference N, and the east-west direction coordinate difference E.

  Furthermore, according to the above-described embodiment, a table is used to calculate the pitch offset p and the roll offset r. Of course, it is possible to calculate in real time by using the expressions p =... And r =. For this purpose, values that simulate the relationship between p and N and r and E in advance are stored in a table. As a result, the pitch offset calculation unit 114 and the roll offset calculation unit 115 can obtain p and r simply by drawing a table based on N and E.

  As described above in detail, according to the portable device, program and method of the present invention, the pitch offset and / or roll offset is calculated from the geomagnetic data and the estimated azimuth obtained by the circumferential movement of the user, and the offset By correcting the gravitational vector, the accuracy of autonomous positioning can be improved regardless of individual differences in the manner of holding the mobile device.

  Various changes, modifications, and omissions of the above-described various embodiments of the present invention can be easily made by those skilled in the art. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

DESCRIPTION OF SYMBOLS 1 Mobile device 101 Acceleration sensor 102 Geomagnetic sensor 111 Autonomous positioning part 112 Coordinate difference derivation part 113 Circumference movement period detection part 114 Estimated azimuth angle buffer part 115 Pitch offset calculation part 116 Roll offset calculation part 117 Application part

Claims (9)

An acceleration sensor that outputs triaxial acceleration data;
A geomagnetic sensor that outputs triaxial geomagnetic data;
A mobile device that calculates a gravity vector using the acceleration data and the geomagnetic data, and has an autonomous positioning means that outputs an estimated azimuth angle d autonomously measured, and estimates the gravity vector,
Estimated azimuth angle buffer means for accumulating the estimated azimuth angle d during circumferential movement of the device based on user behavior;
Coordinate difference deriving after circumference movement of the device, startup position north-south direction coordinate difference obtained by accumulating the change in coordinates of each estimated azimuth d to the end turned position from N (Σcosd) and east-west direction coordinate difference E a (Σsind) Deriving means;
Pitch offset calculating means for calculating a pitch offset p based on the north-south direction coordinate difference N, and / or roll offset calculating means for calculating a roll offset r based on the east-west direction coordinate difference E,
The mobile device characterized in that the autonomous positioning means calculates an estimated azimuth angle d using a gravity vector corrected by the pitch offset p and / or the roll offset r. The pitch offset calculating means has a pitch offset table in which the north-south direction coordinate difference N and the pitch offset p are associated with each other so as to satisfy the following expression:

φ: Depression angle from a predetermined geomagnetic vector to the gravity vector d: Estimated azimuth angle for each step θ: Azimuth angle obtained by approximating a change of d obtained by circumferential movement to a continuous change of 0 to 2π Using the pitch offset table The pitch offset p is derived from the north-south direction coordinate difference N,
The roll offset calculation means has a roll offset table associated with the east-west direction coordinate difference E and the roll offset r so as to satisfy the following expression:

2. The portable device according to claim 1, wherein a roll offset r is derived from the east-west coordinate difference E using the roll offset table. A circumferential movement period detecting means for detecting a circumferential movement period in which the estimated azimuth angle d varies from 0 ° to 360 °;
3. The portable device according to claim 1, wherein the estimated azimuth angle buffer means accumulates the estimated azimuth angle d during the circumferential movement period . An acceleration sensor that outputs triaxial acceleration data;
A geomagnetic sensor that outputs triaxial geomagnetic data;
A computer mounted on a portable device having a function,
A program for estimating a gravity vector, which calculates a gravity vector using the acceleration data and the geomagnetic data, and causes the computer to function as an autonomous positioning means for outputting an estimated azimuth angle d autonomously measured,
Estimated azimuth angle buffer means for accumulating the estimated azimuth angle d during circumferential movement of the device based on user behavior;
Coordinate difference deriving after circumference movement of the device, startup position north-south direction coordinate difference obtained by accumulating the change in coordinates of each estimated azimuth d to the end turned position from N (Σcosd) and east-west direction coordinate difference E a (Σsind) Deriving means;
Pitch offset calculating means for calculating a pitch offset p based on the north-south direction coordinate difference N, and / or roll offset calculating means for calculating a roll offset r based on the east-west direction coordinate difference E,
The program for a portable device, wherein the autonomous positioning means further causes a computer to calculate an estimated azimuth angle d using a gravity vector corrected by the pitch offset p and / or the roll offset r. The pitch offset calculating means has a pitch offset table in which the north-south direction coordinate difference N and the pitch offset p are associated with each other so as to satisfy the following expression:

φ: Depression angle from a predetermined geomagnetic vector to the gravity vector d: Estimated azimuth angle for each step θ: Azimuth angle obtained by approximating a change of d obtained by circumferential movement to a continuous change of 0 to 2π Using the pitch offset table The pitch offset p is derived from the north-south direction coordinate difference N,
The roll offset calculation means has a roll offset table associated with the east-west direction coordinate difference E and the roll offset r so as to satisfy the following expression:

The program for a portable device according to claim 4, wherein the computer is caused to function so as to derive a roll offset r from the east-west coordinate difference E using the roll offset table. A circumferential movement period detecting means for detecting a circumferential movement period in which the estimated azimuth angle d varies from 0 ° to 360 °;
The program for a portable device according to claim 4 or 5, wherein the estimated azimuth angle buffer means further causes a computer to accumulate the estimated azimuth angle d during the circumferential movement period . An acceleration sensor that outputs triaxial acceleration data;
A geomagnetic sensor that outputs triaxial geomagnetic data;
A method of correcting a gravity vector for a portable device having an autonomous positioning function that calculates an estimated azimuth angle d autonomously measured while calculating a gravity vector using the acceleration data and the geomagnetic data,
During circumferential movement of the device based on user behavior, and storing the estimated azimuth angle d, was after circumferential movement of the apparatus, the coordinate variation for each estimated azimuth angle d from startup position to a final turned position cumulatively A first step of deriving a north-south direction coordinate difference N (Σcosd) and an east-west direction coordinate difference E (Σsind) ;
Calculating a pitch offset p based on the north-south direction coordinate difference N and / or calculating a roll offset r based on the east-west direction coordinate difference E;
And a third step in which the autonomous positioning function calculates an estimated azimuth angle d using the gravity vector corrected by the pitch offset p and / or the roll offset r. The calculation of the pitch offset p includes a pitch offset table in which the north-south direction coordinate difference N and the pitch offset p are associated so as to satisfy the following expression:

φ: Depression angle from a predetermined geomagnetic vector to the gravity vector d: Estimated azimuth angle for each step θ: Azimuth angle obtained by approximating a change of d obtained by circumferential movement to a continuous change of 0 to 2π Using the pitch offset table The pitch offset p is derived from the north-south direction coordinate difference N,
The calculation of the roll offset r has a roll offset table in which the east-west coordinate difference E and the roll offset r are associated with each other so as to satisfy the following equation:

The gravity vector correction method according to claim 7, wherein the computer is caused to function so as to derive the roll offset r from the east-west coordinate difference E using the roll offset table. In the first step, a circumferential movement period in which the estimated azimuth angle d changes from 0 ° to 360 ° is detected, and the estimated azimuth angle d in the circumferential movement period is accumulated. The gravity vector correction method according to claim 7 or 8.

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