JP4993758B2 - Portable terminal, program and method for determining direction of travel of pedestrian using acceleration sensor - Google Patents

Description

  The present invention relates to a portable terminal, a program, and a method for determining a pedestrian's traveling direction using an acceleration sensor. In particular, the present invention relates to an autonomous navigation technique for deriving the traveling direction at the current position in real time.

  Conventionally, there is an autonomous navigation technique that derives a traveling direction and a current position in real time using an acceleration sensor and a direction sensor. Autonomous navigation technology is combined with GPS (Global Positioning System) technology and is mainly used for a car navigation system. The car navigation system displays, on a display, an accurate traveling direction and current position, and a travel route guide to a destination for a driver of a car.

  The car navigation system corrects the current position information measured by the GPS by an autonomous navigation technique such as a vehicle speed pulse or a gyro. Further, the road map information is read out as necessary, and the traveling direction and the current position are corrected so that the current travel route coincides with the road (refer to map matching technology based on a projection method, for example, Patent Document 1). As a result, it is possible to prevent the current position from being a position not on the road due to a sensor error.

  On the other hand, there is a system in which such navigation technology is applied to a portable terminal possessed by a pedestrian. Specifically, a cumulative current position from the starting point is derived using the detected “number of steps” of the pedestrian and the “step length” of the pedestrian (see, for example, Patent Document 2). When the autonomous navigation technology is applied to a pedestrian, acceleration components other than horizontal movement are also detected. Thus, the measured distance is derived from the number of steps and the step length, rather than simply integrating the output of the acceleration sensor.

The “number of steps” is detected by taking the acceleration for each axis detected by the acceleration sensor in the mobile terminal as the square root of the sum of squares (√ (x ² + y ² + z ² )) and taking the peak-to-peak as one step (for example, (See Patent Document 3). The “step length” is preset by the user or estimated from the height of the user. Alternatively, according to another technique, there is a technique of calibrating the stride by causing a pedestrian to walk a specified distance (see, for example, Non-Patent Document 1).

  The “traveling direction” is detected by the “direction sensor”. As the direction sensor, a geomagnetic sensor is generally used. There is also a technique for three-dimensionally displaying the orientation and direction of a terminal detected using a geomagnetic sensor on a display (see, for example, Patent Document 4). In addition, when there are a plurality of roads through an intersection in the traveling direction, there is a technique in which the intersection is the current position (see, for example, Patent Document 5).

  A technology to determine the current position using autonomous navigation technology, in order to prevent the influence of the cumulative error of sensor data, when the right turn or left turn at the intersection is detected, the intersection is the starting point for specifying the current position (See, for example, Patent Document 6). That is, every time a turn is detected, the cumulative error of the sensor data is reset, and the previous cumulative error does not affect the subsequent specification of the current position.

  There is also an autonomous navigation technique that determines the traveling direction using the relationship between the vertical acceleration and the traveling direction acceleration after determining the vertical direction of the terminal (see, for example, Patent Document 7).

JP-A-5-061408 Japanese Patent Laid-Open No. 9-089584 Japanese Patent Laying-Open No. 2005-038018 JP 2004-046006 A JP-A-3-099399 JP 63-011813 A JP 2008-039619 A “Nike + iPod User's Guide”, page 27, “online”, [Search April 12, 2008], Internet <URL: http://manuals.info.apple.com/en/nikeipod_users_guide.pdf>

  According to the technique described in Patent Literature 4, it is possible to derive the attitude of the terminal in a stationary state using an acceleration sensor and a geomagnetic sensor. In the stationary state, the acceleration vector detected by the acceleration sensor represents only gravity. Therefore, the terminal posture can be derived from the world coordinate system derived using the gravity vector and the geomagnetic vector.

  However, in actuality, when deriving the traveling direction of a pedestrian carrying a mobile terminal, it is necessary not only to obtain the orientation of the terminal but also to determine which direction of the terminal is the traveling direction of the pedestrian. Become.

  According to the technique described in Patent Document 7, the pedestrian's traveling direction can be determined after the terminal posture is derived. However, it is based on the premise that the posture of the terminal does not change for the period for determining the traveling direction, and when the pedestrian is holding the mobile terminal, the correct posture is determined because the terminal posture changes. I can't.

  Therefore, the present invention provides a portable terminal, a program, and a program that can determine the direction of travel of a pedestrian using an acceleration sensor mounted on the portable terminal when the pedestrian is walking with the portable terminal handheld. It aims to provide a method.

According to the present invention, the mobile terminal is equipped with an acceleration sensor that outputs triaxial acceleration data, and is carried by a pedestrian,
Walking timing determining means for outputting acceleration data for each step or for each time unit based on the number of steps;
Posture determination means for determining the posture of the mobile terminal from the acceleration data,
Attitude determination means
Gravity direction axis direction determining means for determining the gravity direction axis direction from acceleration data;
A rotation axis determining means for approximately calculating a normal vector of an acceleration surface composed of a plurality of acceleration data and determining a rotation axis from the normal vector;
Advancing direction axis is specified based on the gravity direction axis direction and the rotation axis, a plurality of continuous peak points are specified based on the magnitude of the combined acceleration of the acceleration data, and based on the acceleration in the advancing direction axis direction at the peak point And a traveling direction axial direction determining means for determining the traveling direction axial direction.

According to another embodiment of the portable terminal of the present invention, the advancing direction axis direction determining means is
For multiple peak points, “Large” / “Small” of the magnitude of the resultant acceleration appear alternately,
When the acceleration in the direction of travel axis when the magnitude of the combined acceleration is “small” is larger than the acceleration in the direction of travel axis when the magnitude of the combined acceleration is “large”, The direction of “Positive” is determined as the progress direction,
When the acceleration in the direction of the traveling direction when the magnitude of the combined acceleration is “small” is smaller than the acceleration in the direction of the traveling direction axis when the magnitude of the combined acceleration is “large”, “ It is also preferable to determine the “negative” direction as the traveling direction.

According to another embodiment of the mobile terminal of the present invention,
A geomagnetic sensor that outputs triaxial geomagnetic data;
The gravity direction axis is assigned to the judgment reference y-axis, the traveling direction axis is assigned to the judgment reference x-axis, and the judgment reference x-axis is rotated 90 degrees clockwise when the judgment reference z-axis is viewed from above the judgment reference y-axis. Approximate azimuth determining means that determines that the direction rotated clockwise is the direction of the determination reference z-axis and determines the approximate azimuth in units of 90 degrees based on the determination reference x-axis and the determination reference z-axis It is also preferable to further include

According to another embodiment of the mobile terminal of the present invention,
The rough direction determining means is
When the direction of travel is the “negative” direction of the travel direction axis,
If the criterion x-axis is “negative” and the criterion z-axis is “positive”, the traveling direction is determined to be between north and east,
If the criterion x-axis is “positive” and the criterion z-axis is “positive”, the traveling direction is determined to be between south and east,
If the criterion x-axis is “positive” and the criterion z-axis is “negative”, the traveling direction is determined to be between south and west,
If the criterion x-axis is “negative” and the criterion z-axis is “negative”, the traveling direction is determined to be between north and west,
When the traveling direction is the “positive” direction of the traveling direction axis,
When the criterion x-axis is “positive” and the criterion z-axis is “negative”, the traveling direction is determined to be between north and east,
If the criterion x-axis is “negative” and the criterion z-axis is “negative”, the traveling direction is determined to be between south and east,
If the criterion x-axis is “negative” and the criterion z-axis is “positive”, the traveling direction is determined to be between south and west,
When the determination reference x-axis is “positive” and the determination reference z-axis is “positive”, it is also preferable to determine that the traveling direction is between north and west.

  According to another embodiment of the portable terminal of the present invention, the gravity direction axis direction determining means determines the axis having the largest absolute value of the average value in the plurality of acceleration data as the vertical gravity direction axis, and calculates the average value. It is also preferable to determine the downward direction as “positive” if the positive value is “positive” or the positive direction as “positive” if the average value is “negative”.

According to the present invention, there is provided a program that includes an acceleration sensor that outputs triaxial acceleration data and causes a computer mounted on a mobile terminal carried by a pedestrian to function.
Walking timing determining means for outputting acceleration data for each step or for each time unit based on the number of steps;
Causing the computer to function as posture determining means for determining the posture of the mobile terminal from the acceleration data;
Attitude determination means
Gravity direction axis direction determining means for determining the gravity direction axis direction from acceleration data;
A rotation axis determining means for approximately calculating a normal vector of an acceleration surface composed of a plurality of acceleration data and determining a rotation axis from the normal vector;
Advancing direction axis is specified based on the gravity direction axis direction and the rotation axis, a plurality of continuous peak points are specified based on the magnitude of the combined acceleration of the acceleration data, and based on the acceleration in the advancing direction axis direction at the peak point The computer is made to function as a traveling direction axial direction determining means for determining the traveling direction axial direction.

According to the present invention, there is provided a traveling direction determination method that includes an acceleration sensor that outputs triaxial acceleration data and determines a traveling direction using a portable terminal possessed by a pedestrian,
A first step of outputting acceleration data for each step or for each time unit based on the number of steps;
A second step of determining the gravity direction axis direction from the acceleration data;
A third step of approximately calculating a normal vector of an acceleration surface composed of a plurality of acceleration data and determining a rotation axis from the normal vector;
Advancing direction axis is specified based on the gravity direction axis direction and the rotation axis, a plurality of continuous peak points are specified based on the magnitude of the combined acceleration of the acceleration data, and based on the acceleration in the advancing direction axis direction at the peak point And a fourth step of determining the axial direction of the traveling direction.

  According to the portable terminal, the program, and the method of the present invention, when the pedestrian is walking with the portable terminal held by hand, the terminal posture held by the pedestrian using the acceleration sensor mounted on the portable terminal is changed. Can be determined. According to the present invention, since the attitude of the mobile terminal can be specified, the approximate direction of the pedestrian's traveling direction can also be determined by using the geomagnetic sensor.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory diagram illustrating a walking mode of a pedestrian, an acceleration variation direction, and a geomagnetic variation direction.

  According to FIG. 1, a pedestrian is walking while holding a portable terminal and shaking his / her hand back and forth. If such a general walking mode is seen from the lateral direction, the position of the mobile terminal fluctuates back and forth in a pendulum shape while drawing an arc. Further, when viewed from the traveling direction, the position of the mobile terminal fluctuates up and down.

  The shoulder portion of the arm holding the mobile terminal serves as a rotation axis of an arc drawn by the position change of the mobile terminal. This curve variation is detected by an acceleration sensor or a geomagnetic sensor mounted on the portable terminal. That is, a plane (fan shape) composed of the rotation axis and the arc is represented as an acceleration surface (a surface formed by an acceleration vector group). As long as the mobile terminal is shaken by hand, this acceleration plane is parallel to the traveling direction.

Further, the magnitude of the resultant acceleration can be obtained by obtaining the square root (√ (x ² + y ² + z ² )) of the square sum of the acceleration data output from the acceleration sensor. According to FIG. 1, the position A, the position B, and the position C are represented as the position of the mobile terminal held by the pedestrian. The position B is when the hand of the pedestrian is directly below (the lowest point). In the present invention, the orientation of the terminal at the position B is determined.

  The magnitude of the combined acceleration of the handheld mobile terminal at position B is a maximum. On the contrary, the position A and the position C are when the pedestrian's hand is at the highest position (the highest point), and the magnitude of the resultant acceleration is minimal. Gravity is detected at any of position A, position B, and position C. In addition, the position A and the position C are different from each other in the magnitude of the resultant acceleration because the steps are alternately advanced on the left and right. As a result, the acceleration plane based on the arm swing direction, the gravity direction, and the front and rear can be derived from the acceleration data.

  Furthermore, geomagnetism has arrived for pedestrians and mobile terminals. As long as the pedestrian holds the terminal in a constant posture and travels straight in one direction, the arrival direction in the geomagnetic sensor coordinate system is the same. However, in order for a pedestrian to swing his / her portable terminal back and forth, the direction of arrival of geomagnetism varies in a curved manner according to his arm swing. This curve variation is detected by a geomagnetic sensor mounted on the portable terminal.

  The mobile terminal is equipped with an acceleration sensor and a geomagnetic sensor. The sensor is fixed with respect to the terminal, and if the orientation of the terminal is determined, the orientation of the axis of the sensor is also determined.

  FIG. 2 is an explanatory diagram illustrating the sensor x-axis, y-axis, and z-axis in a mobile terminal held by a pedestrian.

  FIG. 2A shows the sensor x-axis, y-axis, and z-axis corresponding to the attitude of the mobile terminal. Here, the portable terminal held by the pedestrian is in a state in which the posture is constantly changing by hand gesture. Unless the attitude of the mobile terminal is determined, the direction cannot be determined based on geomagnetism.

  According to FIG.2 (b), even if the attitude | position of a portable terminal is unknown, the gravity direction axis direction is specified. When the portable terminal is directly below the pedestrian's hand (position B, lowest point), the direction of the gravity direction axis at the position B is determined.

  The gravity direction axis direction uses acceleration data detected by an acceleration sensor. Regarding acceleration x-axis, y-axis, and z-axis acceleration data detected in a predetermined time range, the axis having the largest absolute value of the average acceleration of each axis is the gravity direction axis. Since gravity is detected downward, if the average value of acceleration in the gravity direction axis is `` positive '', the downward direction is `` positive '', and if the average value of acceleration is `` negative '', it is downward Becomes “negative” (upward is “positive”).

  Here, it is assumed that the gravity direction axis direction is the y-axis of the sensor, and the upward direction of the y-axis is “positive”. At this time, the y-axis of the sensor is assigned to the determination reference y-axis.

  When viewed from above the determination reference y-axis, the determination reference x-axis and the determination reference z-axis have the direction of the determination reference x-axis rotated 90 degrees clockwise (clockwise). It is decided to become the direction.

  In the above-described example, the gravity direction axis direction has been described as corresponding to the sensor y axis (upward is “positive”) of the mobile terminal. However, depending on the attitude of the mobile terminal, the gravity direction axis direction may be “positive” in the downward direction, may be the sensor x axis, or may be the sensor z axis.

  Here, regarding the arrangement configuration of the acceleration sensor and the geomagnetic sensor mounted inside the mobile terminal, it is assumed that the x axis of the acceleration sensor and the x axis of the geomagnetic sensor are in the same direction. Similarly, the y-axis of the acceleration sensor and the y-axis of the geomagnetic sensor have the same orientation, and the z-axis of the acceleration sensor and the z-axis of the geomagnetic sensor have the same orientation.

  FIG. 3 is a graph showing numerical examples of the acceleration sensor and the geomagnetic sensor, and walking timing.

According to FIG. 3, the acceleration sensor and the geomagnetic sensor are numerical examples in which 16 pieces of data are output per second, and the pedestrian holding the mobile terminal is in the time range in which the traveling direction is northeast. It is. Based on FIG. 3, the average values of the acceleration sensor x-axis, y-axis, and z-axis are calculated.
Acceleration sensor x-axis: -169.5
Acceleration sensor y-axis: -786.94
Acceleration sensor z-axis: 75.69
At this time, the axis with the largest absolute value of the average acceleration is the y-axis. That is, the y axis is the gravity direction axis. Further, since the average value of the y-axis is “negative”, it can be determined that the y-axis is upward, that is, opposite to gravity. The gravity direction axis is assigned to the criterion y-axis.

  FIG. 3 further shows a graph representing walking timing. The walking timing is determined as the lowest point peak for each step. This timing is the position C in FIG. 1 if the foot is on the side carrying the terminal, and the position A in FIG. 1 if the foot is on the opposite side. The walking timings t1 to t5 are associated with numerical examples. Hereinafter, the procedure for determining the terminal posture and the traveling direction will be described by taking the time point of walking timing t4 as an example. The relationship between the sensor x-axis, y-axis, and z-axis is the same as that shown in FIG.

  FIG. 4 is a vector diagram showing the gravity direction axis direction, the rotation axis, and the traveling direction axis. For simplicity, the sensor y-axis is assigned to the gravity direction axis, the sensor z-axis is assigned to the rotation axis, and the sensor x-axis is assigned to the traveling direction axis, but acceleration and geomagnetism are detected in any direction with respect to the sensor coordinate system. Whether this is done depends on the attitude of the terminal.

  According to FIG. 4, the three-axis acceleration data (x, y, z) obtained from the acceleration sensor and the three-axis geomagnetic data (x, y, z) obtained from the geomagnetic sensor are expressed in three-dimensional coordinates. Plotted in the system. In accordance with an arm swinging motion by a pedestrian holding a mobile terminal, an acceleration plane in which acceleration data is plotted can be detected in parallel with the traveling direction.

  By approximating an acceleration surface on which a plurality of acceleration data is plotted to a plane, a normal vector of the acceleration surface can be derived. The axis having the largest component of the normal vector of the acceleration surface is the rotation axis.

As a method for approximately calculating the acceleration surface, for example, there is a least square method. The least square method is a method of determining each coefficient of the prediction function f (x) for the phenomenon so that the sum of the squares of the residuals is minimized. The residual, and the i-th data _{n i} with respect to the predicted function values f _{(n i),} which is the difference between the measured data _{m i,} i.e. _m i -f _{(n i).}

In general, a plane passing through the origin is represented by the following equation (1).
ax + by + cz = 0 Formula (1)
At this time, (a, b, c) is a normal vector with respect to the plane.

Here, in order to simplify the calculation, Equation (1) is transformed into Equation (2).
z = αx + βy Equation (2)
Since (a, b, c) is a normal vector, there is no problem when c = -1.

When n point groups x _i , y _i , and z _i (i = 1 to n) are given, α and β that minimize the following expression (3) may be calculated.
S = Σ _{i = 1} ⁿ (z _i −αx _i −βy _i ) Equation ² (3)

Here, it is assumed that it is defined as follows.
A = Σ _{i = 1} ⁿ (x _i ² )
B = Σ _{i = 1} ⁿ (y _i ² )
C = Σ _{i = 1} ⁿ (z _i ² )
D = Σ _{i = 1} ⁿ (x _i × y _i )
E = Σ _{i = 1} ⁿ (x _i × z _i )
F = Σ _{i = 1} ⁿ (y _i × z _i )

At this time, the expression (3) becomes the following expression (4).
S = Aα ² + Bβ ² + C + 2αβD-2αE-2βF Formula (4)

When Expression (4) is regarded as a function of α, it becomes a concave quadratic function, and the minimum value is minimized. The same applies to β. That is, S is partially differentiated with respect to α and β, and a point that becomes 0 is obtained.

When the equations (5) and (6) are solved, they can be calculated as the following equations (7) and (8).
α = (BE-DF) / (AB-D ² ) Formula (7)
β = (AF−DE) / (AB−D ² ) Formula (8)
As described above, the normal vector is (α, β, −1).

According to the numerical example of FIG. 3, the normal vector of the acceleration surface is calculated as follows.
Normal vector (-0.0508, -0.0865, -1)
Therefore, the sensor z-axis becomes the rotation axis, that is, the axis in the left-right direction. Since the sensor y-axis is the gravity direction axis and the sensor z-axis is the left-right axis, the sensor x-axis is found to be the traveling direction axis, that is, the front-rear direction axis. Further, the sensor x axis (traveling direction axis) is assigned in the same direction as the determination reference x axis. From the relationship between the determination reference x-axis and the determination reference z-axis, the direction of the sensor z-axis is the same as the direction of the determination reference z-axis.

  Next, the forward axis is determined. Therefore, the lowest point peak for each step is used. At the lowest point peak for each step, the step of the foot on the side holding the terminal and the step of the foot on the opposite side appear alternately, so the magnitude of the combined acceleration is also “large” and “small” Appear alternately. At this time, when the magnitude of the combined acceleration is “small”, it is a foot step on the side carrying the terminal, and the position of the terminal is the position C according to FIG.

  FIG. 5 is an explanatory diagram for identifying the traveling direction by comparing the determination reference x-axis accelerations for the magnitudes “large” and “small” of the combined acceleration.

  For a plurality of peak points in the magnitude of the combined acceleration, “large” / “small” of the magnitude of the combined acceleration appear alternately. Then, when the criterion x-axis acceleration when the magnitude of the combined acceleration is “small” is larger than the criterion x-axis acceleration when the magnitude of the synthesized acceleration is “large”, The direction of “positive” is determined as the traveling direction. Further, when the criterion x-axis acceleration when the magnitude of the combined acceleration is “small” is smaller than the criterion x-axis acceleration when the magnitude of the combined acceleration is “large”, The direction of “negative” is determined as the traveling direction.

For example, with respect to the walking timing in FIG. 3, the combined acceleration is calculated as follows.
t1: Synthetic acceleration 717.70 “Large” (foot walking on the side not carrying the terminal)
t2: Synthetic acceleration 642.59 “Small” (step of the foot on the side carrying the terminal)
t3: Synthetic acceleration 740.43 “Large” (step of the foot on the side not holding the terminal)
t4: Synthetic acceleration 607.24 “Small” (foot walking on the side carrying the terminal)

  The composite acceleration (642.59) at t2 is smaller than the composite acceleration (717.70) at t1, the composite acceleration (740.43) at t3 is larger than the composite acceleration (642.59) at t2, and the composite acceleration at t3. The composite acceleration (607.24) at t4 is smaller than (740.43). Therefore, it is found that t2 and t4 are “foot walking on the side holding the terminal”, and t1 and t3 are “walking foot on the opposite side”.

  Here, the acceleration of the criterion x-axis at the step (t4) for determining the traveling direction is compared with the acceleration of the criterion x-axis at the immediately preceding step (t3). When the criterion x-axis acceleration of “foot walking on the side that owns the terminal” is larger, the “positive” direction of the criterion x-axis is forward (advance direction), and “no terminal is possessed” When the determination reference x-axis acceleration of the “step of the foot on the side” is larger, the “negative” direction of the determination reference x-axis can be determined to be the front (advance direction).

The values of the acceleration x-axis (assigned to the judgment reference x-axis) at t3 and t4 are as follows.
t3: -33
t4: -247
Therefore, the forward direction is “negative” on the acceleration x axis.

  FIG. 6 is an explanatory diagram showing the attitude of the mobile terminal determined according to the present invention. According to FIG. 6, the posture when the mobile terminal is at position B is specified.

  FIG. 7 is an explanatory diagram illustrating a determination reference x-axis and a determination reference z-axis with respect to geomagnetism.

  According to the present invention, since the attitude of the mobile terminal can be specified, it is possible to roughly specify the traveling direction in units of 90 degrees in accordance with the change of the moving average value on the determination reference x axis and the determination reference z axis. it can. Geomagnetism is detected from south to north. Therefore, if the determination reference axis (x-axis or z-axis) is north, the geomagnetism is detected as a “positive” value, and if it is south, the geomagnetism is detected as a “negative” value. . According to FIG. 3, the orientation can be roughly specified as follows.

When the traveling direction is the “negative” direction of the criterion x-axis,
When the determination reference x-axis is “negative” and the determination reference z-axis is “positive”, it is determined that the traveling direction is between north and east.
When the determination reference x-axis is “positive” and the determination reference z-axis is “positive”, it is determined that the traveling direction is between the south and the east.
When the determination reference x-axis is “positive” and the determination reference z-axis is “negative”, it is determined that the traveling direction is between the south and the west.
When the determination reference x-axis is “negative” and the determination reference z-axis is “negative”, it is determined that the traveling direction is between north and west.
When the traveling direction is the “positive” direction of the judgment reference x-axis,
When the determination reference x-axis is “positive” and the determination reference z-axis is “negative”, it is determined that the traveling direction is between north and east.
When the determination reference x-axis is “negative” and the determination reference z-axis is “negative”, it is determined that the traveling direction is between the south and the east.
When the determination reference x-axis is “negative” and the determination reference z-axis is “positive”, it is determined that the traveling direction is between the south and the west.
When the criterion x-axis is “positive” and the criterion z-axis is “positive”, it is determined that the traveling direction is between north and west.

  When moving northward, the forward / backward axis detects geomagnetism with the same sign as the forward axis sign (positive / negative), and when moving westward, the left / right axis is The geomagnetism having the same sign value as the sign (positive or negative) of the rightward axis is detected. Also, when moving southward and eastward, the signs are opposite to each other.

In order to suppress the influence due to the temporary fluctuation of the geomagnetism, it is preferable to use the total value or the average value of the values of the geomagnetic sensor detected in the predetermined range time when determining the moving direction. The total value of geomagnetism detected per second using the numerical example of FIG. 3 is as follows.
Judgment standard x-axis -4708
Judgment standard z-axis 3172
At this time, the x-axis is the same “negative” sign as the forward sign, and the z-axis is the “positive” sign opposite to the right-point sign. Accordingly, the traveling direction can be specified as being northeast.

  FIG. 8 is a functional configuration diagram of the mobile terminal according to the present invention.

  According to FIG. 8, the mobile terminal 1 includes a microprocessor unit 10, a geomagnetic sensor 11, an acceleration sensor 12, a GPS unit 13, a map information storage unit 14, and a display unit 15.

  The geomagnetic sensor 11 measures the direction of geomagnetism in three axial directions (front-rear direction, left-right direction, and up-down direction). The geomagnetic sensor 11 separates the Hall elements and outputs values detected from the separated Hall elements.

  The acceleration sensor 12 detects acceleration, that is, a change in speed per unit time. In the case of the three-axis type that can detect the tilt of the mobile terminal, three-dimensional acceleration can be detected, and measurement of the gravity (static acceleration) of the earth can be supported.

  The GPS unit 13 measures latitude and longitude information that is the current position of the reference. Using the measured current position as a reference point, the current position of the pedestrian can be integrated according to the number of steps, the step length, and the traveling direction.

  The map information storage unit 14 stores map information representing a travel route such as a road map. The display unit 15 displays the traveling direction and the current position output from the microprocessor unit 10 together with the map information. This provides a navigation function for pedestrians.

  The microprocessor unit 10 executes a program that functions as the walking timing determination unit 101, the posture determination unit 102, the approximate orientation determination unit 103, the stride determination unit 104, the movement amount integration unit 105, and the current position determination unit 106. To do.

  The walking timing determination unit 101 divides the acceleration data string output from the acceleration sensor 12 into acceleration data for every predetermined time, for example, for each number of steps, or for each time unit based on the number of steps. For example, the number of steps can be calculated from the change in the combined acceleration, that is, the degree of shaking during movement.

  The posture determination unit 102 determines the posture of the mobile terminal held by the pedestrian when the gravity direction axis is downward.

  The approximate orientation determining unit 103 determines an approximate orientation in units of 90 degrees based on the geomagnetic data for the orientation of the mobile terminal determined by the orientation determining unit 102.

  The stride determination unit 104 receives acceleration data for one step from the walking timing determination unit 102 and determines the stride for each step. The determined stride length is output to the movement amount accumulating unit 105. The stride is determined by the change in the combined acceleration, that is, the degree of shaking during movement and the body shape of the pedestrian.

  The movement amount accumulating unit 105 receives step information for one step from the step determining unit 104, integrates the step for one step, and determines the amount of movement. The movement amount is output to the current position determination unit 106.

  The current position determination unit 106 acquires map information from the map information storage unit 14 and identifies the current position from the accumulated movement amount. The current position determination unit 106 determines the current position by performing map matching on the map information based on the movement amount output from the movement amount integration unit 105 and the azimuth output from the approximate azimuth determination unit 103.

  The posture determination unit 102, which is a feature of the present invention, includes a gravity direction axis direction determination unit 1021, a rotation axis determination unit 1022, and a traveling direction axis direction determination unit 1023.

  The gravity direction axis direction determination unit 1021 determines the gravity direction axis direction from the acceleration data. The gravity direction axis direction determination unit 1021 calculates an average value of the sensors x-axis, y-axis, and z-axis of the plurality of acceleration sensors for a predetermined time range. The axis with the largest average absolute value of acceleration is the gravity direction axis. Further, the gravity direction axis direction is determined depending on whether the average value of the gravity direction axis is “positive” or “negative”.

  The rotation axis determination unit 1022 approximately calculates a normal vector of an acceleration plane composed of a plurality of acceleration data, and determines a rotation axis from the normal vector.

  The advancing direction axis direction determination unit 1023 identifies the advancing direction axis based on the gravity direction axis direction and the rotation axis, and based on the acceleration in the advancing direction axis direction at a plurality of continuous peak points in the magnitude of the combined acceleration of the acceleration data. To determine the direction of travel axis.

  As described above in detail, according to the mobile terminal, the program, and the method of the present invention, when a pedestrian is walking with the mobile terminal handheld, the acceleration sensor mounted on the mobile terminal is used. The traveling direction of the pedestrian can be determined. According to the present invention, since the attitude of the mobile terminal can be specified, the approximate direction of the pedestrian's traveling direction can also be determined by using the geomagnetic sensor.

  In the various embodiments of the present invention described above, various changes, modifications, and omissions in the scope of the technical idea and the viewpoint 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.

It is explanatory drawing showing the walk mode of a pedestrian, and a geomagnetic fluctuation direction. It is explanatory drawing showing the sensor x-axis, y-axis, and z-axis in the portable terminal which a pedestrian holds. It is a graph showing the numerical example of an acceleration sensor and a geomagnetic sensor, and walking timing. It is a vector diagram showing a gravity direction axis direction, a rotation axis, and a traveling direction axis. It is explanatory drawing which compares the x-axis acceleration in the magnitude | size of a synthetic | combination acceleration with "small", and identifies advancing direction. It is explanatory drawing showing the attitude | position of the portable terminal determined by this invention. It is explanatory drawing showing the determination reference | standard x axis and determination reference | standard z axis | shaft with respect to geomagnetism. It is a functional block diagram of the portable terminal in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile terminal 10 Microprocessor part 101 Walking timing determination part 102 Posture determination part 1021 Gravity direction axis direction determination part 1022 Rotation axis determination part 1023 Travel direction axis direction determination part 103 Outline direction determination part 104 Step length determination part 105 Movement amount accumulation part 106 Current position determination unit 11 Geomagnetic sensor 12 Acceleration sensor 13 GPS unit 14 Map information storage unit 15 Display unit

Claims (7)

A mobile terminal equipped with an acceleration sensor that outputs triaxial acceleration data and possessed by a pedestrian,
Walking timing determining means for outputting the acceleration data for each step or for each time unit based on the number of steps;
Posture determining means for determining the posture of the mobile terminal from the acceleration data;
The posture determining means includes
Gravity direction axis direction determining means for determining the gravity direction axis direction from the acceleration data;
A rotation axis determining means for approximately calculating a normal vector of an acceleration surface composed of a plurality of acceleration data and determining a rotation axis from the normal vector;
A traveling direction axis is specified based on the gravity direction axis direction and the rotation axis, a plurality of continuous peak points are specified based on the magnitude of the combined acceleration of the acceleration data, and the traveling direction axis direction at the peak point is determined. A portable terminal comprising: a traveling direction axis direction determining unit that determines a traveling direction axis direction based on acceleration. The advancing direction axis direction determining means includes:
For the plurality of peak points, “large” / “small” of the magnitude of the resultant acceleration appear alternately,
When the magnitude in the direction of travel axis when the magnitude of the combined acceleration is "small", the acceleration in the direction of axis of travel when the magnitude of the synthesized acceleration is "large", Determine the positive direction of the direction of travel axis as the direction of travel,
When the acceleration in the direction of travel axis when the magnitude of the combined acceleration is “small”, the acceleration in the direction of travel axis is smaller than when the magnitude of the combined acceleration is “large”, The mobile terminal according to claim 1, wherein the “negative” direction of the traveling direction axis is determined as the traveling direction. A geomagnetic sensor that outputs triaxial geomagnetic data;
When the gravitational direction axis is assigned to the judgment reference y-axis, the traveling direction axis is assigned to the judgment reference x-axis, and the judgment reference z-axis is viewed from above the judgment reference y-axis, the orientation of the judgment reference x-axis is 90 degrees. Approximate orientation in which the direction rotated clockwise (clockwise) is determined to be the orientation of the determination reference z-axis, and the approximate orientation is determined in units of 90 degrees based on the determination reference x-axis and the determination reference z-axis The mobile terminal according to claim 1, further comprising a determination unit. The approximate orientation determining means includes
When the traveling direction is the “negative” direction of the traveling direction axis,
If the criterion x-axis is “negative” and the criterion z-axis is “positive”, the traveling direction is determined to be between north and east,
If the criterion x-axis is “positive” and the criterion z-axis is “positive”, the traveling direction is determined to be between south and east,
If the criterion x-axis is “positive” and the criterion z-axis is “negative”, the traveling direction is determined to be between south and west,
If the criterion x-axis is “negative” and the criterion z-axis is “negative”, the traveling direction is determined to be between north and west,
When the traveling direction is the “positive” direction of the traveling direction axis,
When the criterion x-axis is “positive” and the criterion z-axis is “negative”, the traveling direction is determined to be between north and east,
If the criterion x-axis is “negative” and the criterion z-axis is “negative”, the traveling direction is determined to be between south and east,
If the criterion x-axis is “negative” and the criterion z-axis is “positive”, the traveling direction is determined to be between south and west,
4. The method according to claim 1, wherein when the determination reference x-axis is “positive” and the determination reference z-axis is “positive”, the traveling direction is determined to be between north and west. The portable terminal of Claim 1.   The gravity direction axis direction determining means determines the axis having the largest absolute value of the average value in the plurality of acceleration data as the vertical gravity direction axis, and if the average value is “positive”, the downward direction is “positive”. Or, if the average value is “negative”, the upward direction is determined as “positive”. The mobile terminal according to claim 1, A program that includes an acceleration sensor that outputs triaxial acceleration data and causes a computer mounted on a portable terminal carried by a pedestrian to function,
Walking timing determining means for outputting the acceleration data for each step or for each time unit based on the number of steps;
Causing the computer to function as posture determining means for determining the posture of the mobile terminal from the acceleration data;
The posture determining means includes
Gravity direction axis direction determining means for determining the gravity direction axis direction from the acceleration data;
A rotation axis determining means for approximately calculating a normal vector of an acceleration surface composed of a plurality of acceleration data and determining a rotation axis from the normal vector;
A traveling direction axis is specified based on the gravity direction axis direction and the rotation axis, a plurality of continuous peak points are specified based on the magnitude of the combined acceleration of the acceleration data, and the traveling direction axis direction at the peak point is determined. A program for a portable terminal, which causes a computer to function as a traveling direction axis direction determining unit that determines a traveling direction axis direction based on acceleration. A traveling direction determination method including an acceleration sensor that outputs triaxial acceleration data, and determining a traveling direction using a mobile terminal carried by a pedestrian,
A first step of outputting the acceleration data for each step or time unit based on the number of steps;
A second step of determining a gravity direction axis direction from the acceleration data;
A third step of approximately calculating a normal vector of an acceleration surface composed of a plurality of acceleration data and determining a rotation axis from the normal vector;
A traveling direction axis is specified based on the gravity direction axis direction and the rotation axis, a plurality of continuous peak points are specified based on the magnitude of the combined acceleration of the acceleration data, and the traveling direction axis direction at the peak point is determined. And a fourth step of determining the direction of the traveling direction axis based on the acceleration.

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