JP2015004593A - Navigation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a navigation device capable of detecting a fitting angle in yaw direction with high accuracy by using a monoaxial acceleration sensor and a monoaxial speed sensor.SOLUTION: A fitting angle detection history creation unit 20 creates a most recent history for a predetermined number of sets, one set consisting of a measured value of acceleration measured by an acceleration measurement unit 16 and an estimated value of acceleration estimated by an acceleration estimation unit 17. A yaw direction fitting angle detection unit calculates, on the basis of the created history for each set, a standard deviation of a difference between the estimated value of acceleration and the measured value of acceleration for each angle for which the estimated value of acceleration is calculated, and calculates, as a fitting angle in yaw direction, an angle used in the calculation of imparting an estimated value of acceleration in which the standard deviation of difference is minimized. The fitting angle detection history creating unit 20 may create the history using, as one set, the measured value of acceleration, the speed and forward/backward acceleration measured by a distance measurement unit 14, and a yaw angle measured by a yaw angle measurement unit 15.

Description

  The present invention relates to a navigation device that is mounted on a mobile body and performs route guidance from a current location to a destination.

  The navigation device is mounted on a vehicle such as an automobile, for example, and displays the position of the vehicle and route guidance from the current location to the destination on a road map displayed on the display screen. When displaying the position of a vehicle on a road map, the attitude angle, inertial force, etc. of the vehicle are measured or observed using a global positioning system (abbreviation: GPS) and various sensors. Then, the position of the vehicle is updated on the road link of the map data by a process called map matching.

  The navigation device may be attached to a vehicle with a case tilted. When the housing is mounted with an inclination, the detection axes of the sensors such as the angular velocity sensor and the acceleration sensor are also inclined. In order to accurately measure the posture angle, inertial force, and the like using the angular velocity sensor and the acceleration sensor, it is necessary to consider the characteristics of the angular velocity sensor and the acceleration sensor whose detection axes are inclined.

  Further, in order to obtain the vehicle position, posture angle, inertial force, and the like by navigation calculation, it is necessary to determine an orthogonal three-axis coordinate system that expresses them. In particular, when the casing of the navigation device is installed in a vehicle inclined at a predetermined mounting angle, a plurality of coordinate systems that express the attitude angle and inertial force of the vehicle are defined. It is necessary to convert sensor measurement values.

  In converting sensor measurement values, there has been proposed a method of using rotation with respect to a reference coordinate system when moving from a reference coordinate system to another coordinate system. This rotation is represented by rotation angles in the roll direction, the pitch direction, and the yaw direction, which are rotation angles with respect to the X, Y, and Z axes.

A plurality of definitions of the X, Y, and Z axes of the coordinate system have been proposed. For example, in the vehicle body coordinate system shown in FIG. 2 to be described later (Body-Frame), the axis extending in the longitudinal direction of the vehicle body 10 is called the X _B axis, a lateral direction of the vehicle body 10, perpendicular to the longitudinal direction of the vehicle body 10 an axis extending in a direction called the Y _B axis, a vertical direction of the vehicle body 10, the axis extending in the direction perpendicular to the longitudinal direction and the lateral direction of the vehicle body 10 of Z _B axis.

Further, in the sensor coordinate system shown in FIG. 3 to be described later (Sensor-Frame), X, Y, Z -axis (hereinafter, respectively, _{X S} axis, _{Y S} axis, there is a case that _{Z S} axis), the vehicle body coordinate system the X, Y, Z-axis, i.e. _{X B-axis, Y B} axis, with respect to _{Z B} axis, the roll direction, the pitch direction, the yaw direction of the mounting angle [theta] r, theta] p, are inclined at [theta] y.

The mounting angle of the navigation device is detected using sensors in the respective axial directions (see, for example, Patent Documents 1 to 4). For example, the technique disclosed in Patent Document 1 uses the same vehicle body coordinate system and sensor coordinate system as those shown in FIGS. 2 and 3 described later. In the technique disclosed in Patent Document 1, at least a biaxial acceleration sensor and a biaxial angular velocity sensor are used. The angular velocity sensor of biaxial detects a roll angular velocity is an angular velocity of the X _S axis of the sensor coordinate system, and a yaw rate is the angular velocity of the Z _S axis.

In the technique disclosed in Patent Document 2, a vehicle body coordinate system and a sensor coordinate system different from the coordinate systems shown in FIGS. 2 and 3 described later are used. In the technique disclosed in Patent Document 2, a biaxial acceleration sensor, uniaxial, specifically by using the angular velocity sensor of Z _S axis, mounted angle in the pitch direction and the yaw direction are detectable .

In the technique disclosed in Patent Document 3, a vehicle body coordinate system obtained by rotating an X axis in FIG. In the technique disclosed in Patent Document 3, the one-axis acceleration sensor for example X _S axis, one axis for example, using an angular velocity sensor of the Z _S axis, the pitch direction, the yaw direction, the roll direction of all three axes of the mounting A corner can be detected.

In the technique disclosed in Patent Document 4, the same vehicle coordinate system and sensor coordinate system as those shown in FIGS. 2 and 3 described later are used. In the technique disclosed in Patent Document 4, a one-axis acceleration sensor for example X _S axis, one axis for example, using an angular velocity sensor of the Z _S axis, the pitch direction mounted angle θp and the yaw direction mounted angle θy is detected The

Japanese Patent No. 4655901 (Claims 1 and 6, paragraphs [0006], [0012] to [0015], [0026] to [0036]) JP-A-2005-147696 (Claims 1 and 8, paragraphs [0007] to [0010], [0013] to [0014], [0031] to [0045], [0070] to [0077]) Japanese Patent No. 4739378 (claims 1 to 3, paragraphs [0005], [0019] to [0021], [0035] to [0044]) Japanese Patent No. 4444321 (Claims 1 and 2, paragraphs [0021], [0028], [0039] to [0041], [0050], [0056] to [0060])

  For example, when a vehicle travels on a slope such as a loop bridge or a multilevel parking lot, the navigation device mounted on the vehicle has a problem that the sensitivity decreases because the detection axis of the angular velocity sensor is inclined. On the other hand, if the correction formula is used, for example, even if the vehicle travels on a slope, the decrease in the sensitivity of the yaw angle can be corrected.

However, in an acceleration sensor whose detection axis is inclined in the yaw direction, the longitudinal acceleration is attenuated according to the mounting angle θp in the yaw direction, and is affected by the lateral acceleration, that is, centrifugal force. As a result, the pitch angle φ _Hp cannot be correctly measured from the acceleration sensor.

  If the inaccurate pitch angle is used to correct a decrease in the sensitivity of the yaw angle, there is a problem that an azimuth error occurs when the vehicle travels on a slope such as the loop bridge or the multilevel parking lot. In order to solve this problem, it is necessary to detect the mounting angle in the yaw direction.

  Further, the automatic detection performance of each mounting angle in the pitch direction and the yaw direction is determined by the configuration of the sensor built in the navigation device. For example, if a 3-axis acceleration sensor and a 3-axis angular velocity sensor are provided, the 3-axis sensor measurement values necessary to detect the 3-axis mounting angle can be used, but it is expensive because of high performance. become.

  In contrast, a so-called low-priced navigation device that cannot use a three-axis acceleration sensor and a three-axis angular velocity sensor does not have a sensor measurement value of a detection axis that is not provided, but is approximately 45 ° or less in both the pitch direction and the yaw direction. The user is required to be able to cope with the mounting angle.

  In the navigation devices disclosed in Patent Documents 1 and 2 described above, since it is necessary to provide an acceleration sensor having two or more axes, it can be used as a low-priced navigation device that uses only one-axis acceleration and one-axis angular velocity sensors. Can not.

  Further, in the navigation device disclosed in Patent Document 3 described above, the built-in sensors are a uniaxial acceleration sensor and a uniaxial angular velocity sensor, but all three axes can be detected. However, in the technique disclosed in Patent Document 3, the pitch direction mounting angle θp is calculated without considering the characteristics of the angular velocity sensor and the acceleration sensor in which the detection axis is inclined.

  The formula used in the technique disclosed in Patent Document 3 is a calculation formula for detecting the pitch direction mounting angle θp when the vehicle is stopped on a horizontal plane. The technique disclosed in Patent Document 3 does not consider a method of detecting a horizontal plane on an actual road or parking lot where various inclination angles exist. Therefore, there is a problem that the detection error of the pitch direction mounting angle θp becomes large, and the accuracy of the yaw direction mounting angle θy calculated using the pitch direction mounting angle θp is not sufficient.

  In each of the navigation devices disclosed in Patent Documents 1 to 3, since the mounting angle is detected only when the vehicle is traveling on a horizontal plane, it is possible to determine whether or not the vehicle is traveling on a horizontal plane. However, this affects the detection accuracy of the mounting angle, and finally becomes a major factor that determines the positional accuracy of the vehicle.

  In addition, the navigation device disclosed in Patent Document 4 described above includes only a uniaxial acceleration sensor and a uniaxial angular velocity sensor as sensors, as in the technique disclosed in Patent Document 3. In the technique disclosed in Patent Literature 4, even if the vehicle travels on a road including a slope or a parking lot, it is automatically determined whether or not the vehicle is traveling on a horizontal plane, and the pitch direction mounting angle θp is detected. In addition, the yaw direction attachment angle θy is detected when the vehicle turns left or right on a horizontal plane.

  However, the technique disclosed in Patent Document 4 deals with the difference itself between the acceleration measurement value obtained by the acceleration sensor and the acceleration estimation value for the detection of the yaw direction attachment angle θy. Therefore, if the acceleration sensor has a zero point error equivalent to about 1 ° and temperature fluctuation (drift), the detection accuracy of the yaw direction mounting angle θy may be lowered.

  The objective of this invention is providing the navigation apparatus which can detect a yaw direction installation angle accurately using a 1 axis | shaft acceleration sensor and a 1 axis | shaft angular velocity sensor.

  The navigation device of the present invention is a navigation device that can be mounted on a moving body, and as a signal corresponding to the speed of the moving body, a speed sensor that outputs a pulse signal corresponding to the moving distance of the moving body, and a housing of the device itself. An angular velocity sensor having a detection axis for detecting the angular velocity of the moving body in the vertical direction of the body and outputting a signal corresponding to the angular velocity, and a direction along the traveling direction of the moving body, the front-rear direction of the housing of the device itself The sensor has a detection axis for detecting the acceleration of the moving object, and outputs the signal corresponding to the acceleration, and the moving distance, speed and longitudinal acceleration of the moving object based on the pulse signal output from the speed sensor. A distance measuring unit for measuring, a yaw angle measuring unit for measuring the angular velocity and yaw angle of the moving body in the direction of a predetermined detection axis for each predetermined timing, and a predetermined timing In addition, an acceleration measuring unit that measures the acceleration of the moving body in the direction of the predetermined detection axis and a search angle range that is a search range of the mounting angle of the housing in the yaw direction are determined at each predetermined angular increment. An acceleration estimation unit that estimates the acceleration of the moving body in the direction of the detection axis corresponding to the mounting angle in the body pitch direction, an acceleration measurement value measured by the acceleration measurement unit, and an acceleration estimation value estimated by the acceleration estimation unit Or a set of acceleration measurements, the velocity and longitudinal acceleration measured by the distance measuring unit, and the yaw angle measured by the yaw angle measuring unit as one set, for the latest predetermined number of sets. Acceleration estimation value and acceleration measurement for each angle at which acceleration estimation value is calculated based on the installation angle detection history creation unit that creates history and the history of each set created And a yaw direction attachment angle detection unit for obtaining the angle used for the calculation that gives the estimated acceleration value that minimizes the standard deviation of the difference as the attachment angle of the housing in the yaw direction. It is characterized by that.

  According to the navigation device of the present invention, a case mounting angle in the yaw direction (hereinafter referred to as “yaw direction mounting angle”) using an acceleration sensor having a single detection axis and an angular velocity sensor having a single detection axis. Can be detected). In the search angle range of the yaw direction mounting angle, the angle at which the standard deviation of the difference between the estimated acceleration value and the measured acceleration value is minimized is the yaw direction mounting angle. And less susceptible to temperature fluctuations (drift). Even if there is a gentle road slope, the yaw direction mounting angle can be detected.

It is a block diagram which shows the structure of the navigation apparatus 1 which is the 1st Embodiment of this invention. It is a figure which shows the coordinate system used with the navigation apparatus 1 of the 1st Embodiment of this invention. It is a figure which shows the coordinate system used with the navigation apparatus 1 of the 1st Embodiment of this invention. It is a flowchart which shows the process sequence of the attitude | position and inertial force measurement process in the navigation apparatus 1 of the 1st Embodiment of this invention. It is a flowchart which shows the process sequence of the attitude | position and inertial force measurement process in the navigation apparatus 1 of the 1st Embodiment of this invention. Is a graph showing an example of the estimated value of the X _S axis acceleration. For estimate and the measurement values of X _S axis accelerations stored in the latest number of histories predetermined is a graph illustrating a method for detecting the yaw direction mounted angle from the standard deviation of the difference for each angular increment the predetermined. It is an enlarged view of the area | region 40 shown in FIG. Is a graph showing the measured value and the estimated value of the X _S axis acceleration. X _S axis acceleration measurement values X _B axis acceleration converted from, and is a graph showing an example of X _B axis acceleration by the speed sensor. It is a graph showing the measured value and the estimated value of Y _S axis acceleration. It is a graph which shows the measured value and estimated value of Z _S- axis acceleration. It is a block diagram which shows the structure of the navigation apparatus 2 which is the 2nd Embodiment of this invention. It is a flowchart which shows the process sequence of the attitude | position / inertia force measurement process in the navigation apparatus 2 which is the 2nd Embodiment of this invention. It is a flowchart which shows the process sequence of the attitude | position / inertia force measurement process in the navigation apparatus 2 which is the 2nd Embodiment of this invention. It is a figure which shows the coordinate system used by the 1st assumption technique. It is a figure which shows the coordinate system used by the 1st assumption technique. It is a figure which shows the coordinate system used by the 2nd prerequisite technique. It is a figure which shows the coordinate system used by the 2nd prerequisite technique. It is a figure which shows the coordinate system used by the 3rd premise technique. 2 is a diagram illustrating an example of a traveling state of a vehicle 50. FIG. 2 is a diagram illustrating an example of a traveling state of a vehicle 50. FIG.

<Prerequisite technology>
Before describing the navigation device of the present invention, the navigation device of the base technology of the present invention will be described. The navigation device is mounted on a moving body, for example, a vehicle such as an automobile, and performs position display of the vehicle and route guidance from the current location to the destination on a road map displayed on the display screen.

  When displaying the position of a vehicle on a road map, the attitude angle, inertial force, etc. of the vehicle are measured or observed using a global positioning system (abbreviation: GPS) and various sensors. Then, the position of the vehicle is updated on the road link of the map data by a process called map matching.

  The navigation device may be attached to a vehicle with a case tilted. When the housing is mounted with an inclination, the detection axes of the sensors such as the angular velocity sensor and the acceleration sensor are also inclined. The detection axes of the angular velocity sensor and the acceleration sensor are inclined in the pitch direction and the yaw direction, for example. In order to accurately measure the posture angle and inertial force using the angular velocity sensor and the acceleration sensor whose detection axis is inclined in the pitch direction and the yaw direction, it is necessary to consider the following characteristics (1) to (4) There is.

  (1) The angular velocity sensor and the acceleration sensor measure the angular velocity and acceleration acting on the detection axis, respectively. When the detection axis is tilted, the sensitivity of the angular velocity and acceleration acting on the detection axis is lowered according to the tilt angle, and conversely, the sensitivity of other axes in the tilt direction is increased. When the detection axis tilts in three dimensions depending on the mounting angle, the angular velocity and acceleration distributed to each axis are detected according to the mounting angle.

  (2) In the case of a 3-axis sensor, a 3-axis sensor signal can be converted into a sensor signal of an arbitrary detection axis at an arbitrary mounting angle. However, in the case of a 2-axis or 1-axis sensor, there are no angular velocities and accelerations that should be measured with a detection axis that is not provided. That is, it cannot be restored.

  (3) Regarding the angular velocity sensor, since the angular velocity does not occur when the vehicle is stopped, the angular velocity measured while the vehicle is stopped can be regarded as a zero point.

  (4) Since the acceleration sensor always detects the gravitational component due to the detection axis inclination, it is impossible to determine the inclination factor of the detection axis, such as the mounting angle and the road inclination angle, only by the acceleration sensor. Therefore, the acceleration while the vehicle is stopped cannot be regarded as a zero point.

  Further, in order to obtain the vehicle position, posture angle, inertial force, and the like by navigation calculation, it is necessary to determine an orthogonal three-axis coordinate system that expresses them. In particular, when the casing of the navigation device is installed in a vehicle inclined at a predetermined mounting angle, a plurality of coordinate systems that express the attitude angle and inertial force of the vehicle are defined. It is necessary to convert sensor measurement values.

  In converting sensor measurement values, there has been proposed a method of using rotation with respect to a reference coordinate system when moving from a reference coordinate system to another coordinate system. This rotation is represented by rotation angles in the roll direction, the pitch direction, and the yaw direction, which are rotation angles with respect to the X, Y, and Z axes. In the following description, the rotation angle in the roll direction may be referred to as “roll angle”, the rotation angle in the pitch direction may be referred to as “pitch angle”, and the rotation angle in the yaw direction may be referred to as “yaw angle”.

  A plurality of definitions of the X, Y, and Z axes of the coordinate system have been proposed. Here, with reference to FIG. 2 described later, a vehicle body coordinate system (Body-Frame) constituted by axes extending in the front-rear direction, the left-right direction, and the up-down direction of the vehicle body 10 will be described as a reference coordinate system.

The vehicle body coordinate system, the axis extending in the longitudinal direction of the vehicle body 10 is called the X _B axis, a lateral direction of the vehicle body 10, refers to the axis extending in the direction perpendicular to the longitudinal direction of the vehicle body 10 and the Y _B axis, the vehicle body 10 of a vertical direction, an axis extending in the direction perpendicular to the longitudinal direction and the lateral direction of the vehicle body 10 of Z _B axis. The subscript “B” in the name of each axis indicates “Body-Frame”. Details of each axis will be described later.

In addition, a sensor coordinate system (Sensor-Frame) that is a coordinate system indicated by the sensor detection axis will be described with reference to FIG. 3 described later. X of the sensor coordinate system, Y, Z-axis (hereinafter, respectively, _{X S} axis, _{Y S} axis, there is a case that _{Z S} axis), the vehicle body coordinate system of X, Y, Z-axis, i.e. _{X B-axis,} Y It is inclined with respect to the _B axis and Z _B axis at respective mounting angles θr, θp, and θy in the roll direction, the pitch direction, and the yaw direction. The subscript “S” in the name of each axis indicates “sensor coordinate system (Sensor-Frame)”.

If the mounting angles θr, θp, θy in the roll direction, pitch direction, and yaw direction (hereinafter, referred to as roll direction mounting angle θr, pitch direction mounting angle θp, and yaw direction mounting angle θy, respectively) are known, the coordinate transformation matrix C _BS to convert the system to the sensor coordinate system can be calculated by the following equation (1). Using this coordinate transformation matrix C _BS, by the following equation (2), it is possible to coordinate transformation a metered amount M _B of the vehicle body coordinate system to the measurement quantity M _S of the sensor coordinate system.

Similarly, if the mounting angles θr, θp, and θy in the roll direction, the pitch direction, and the yaw direction are known, a coordinate conversion matrix C _SB for converting from the sensor coordinate system to the vehicle body coordinate system can be obtained by the following equation (3). it can. Using this coordinate transformation matrix C _SB, by the following equation (4), a metered amount M _S of the sensor coordinate system can be coordinate transformation on the measurement quantity M _B of the vehicle body coordinate system. This measurement amount is a posture angle or an inertial force depending on the calculation purpose.

  The mounting angle of the navigation device is detected by making full use of the coordinate conversion formulas of the above formulas (1) to (4).

  16 and 17 are diagrams showing a coordinate system used in the first prerequisite technology. The navigation device 51 is mounted on the vehicle 50. In the first base technology, the navigation device 51 uses the same vehicle body coordinate system and sensor coordinate system as those shown in FIGS. The first prerequisite technique corresponds to the technique disclosed in Patent Document 1 described above. In FIG. 16, an arrow indicated by reference numeral “52” represents rotation in the pitch direction. In FIG. 17, an arrow indicated by reference numeral “53” represents rotation in the yaw direction.

In the first base technology, the navigation device 51 includes an acceleration sensor having at least two detection axes and an angular velocity sensor having two detection axes. A combination of axes is not specified for the biaxial acceleration sensor. The angular velocity sensor of biaxial detects a roll angular velocity is an angular velocity around the X _S axis of the sensor coordinate system, and a yaw rate is the angular velocity about the Z _S axis of the sensor coordinate system.

  In the first base technology, the mounting angles in the pitch direction and the yaw direction can be detected. When the mounting angle calculated using the acceleration sensor of two or more axes matches the mounting angle calculated using the angular velocity sensor of two or more axes, it is adopted as the mounting angle.

In the first base technology, the roll direction mounting angle θr is fixed at 0 °. Therefore, the coordinate transformation matrix C _BS of the above-described formula (1) for transforming from the vehicle body coordinate system to the sensor coordinate system is represented by the following formula (5) based only on the pitch direction mounting angle θp and the yaw direction mounting angle θy. To be simplified.

Using the coordinate transformation matrix _{C BS} of formula (5), the following equation (6) and (7), the three-axis acceleration _A B of the vehicle body coordinate system _{(A BX, A BY, A} BZ) and 3-axis angular-velocity ω _B (ω _BX , ω _BY , ω _BZ ) is _converted into the triaxial acceleration A _S (A _SX , A _SY , A _SZ ) and the triaxial angular velocity ω _S (ω _SX , ω _SY , ω _SZ ) of the sensor coordinate system. Each is converted.

  From the relationship between Expression (6) and Expression (7), the acceleration and angular velocity of each of the X, Y, and Z axes of the sensor coordinate system are individually obtained by the following Expressions (8) to (13).

Here, assuming that the acceleration calculated from the pulse signal output from the speed sensor is A _SPD and the gravitational acceleration is G, the triaxial acceleration of the vehicle body coordinate system when the vehicle 50 is traveling straight on the horizontal plane. _AB becomes (A _SPD , 0, G). By substituting this into equation (9), equation (9) is transformed into equation (14). The yaw direction attachment angle θy is estimated using equation (14).

Further, from A _BY = 0, Expression (8) and Expression (10) are simplified to Expression (15) and Expression (16), respectively. Using formula (15) and formula (16), the pitch direction mounting angle θp is estimated.

Further, when the vehicle 50 is traveling while turning on a horizontal plane, the triaxial angular velocity ω _B of the vehicle body coordinate system is (0, 0, ω _BZ ). By substituting this into the equations (11) and (13), the equations (11) and (13) are simplified to the following equations (17) and (18), respectively. From the equations (17) and (18), the pitch direction attachment angle θp is calculated by the following equation (19).

  18 and 19 are diagrams showing a coordinate system used in the second base technology. In the second base technology, a vehicle body coordinate system and a sensor coordinate system different from the coordinate systems shown in FIGS. 2 and 3 described later are used. The second prerequisite technique corresponds to the technique disclosed in Patent Document 2 described above.

In the second base technology of the navigation device 51, a biaxial acceleration sensor, uniaxial, specifically by using the angular velocity sensor of Z _S axis, mounted angle in the pitch direction and yaw direction is detectable The

When the vehicle 50 is turning on a horizontal plane, the velocity calculated from the pulse signal output from the velocity sensor is V _SPD , the acceleration is A _SPD , the yaw rate is ω _BZ , and the X axis of the vehicle body coordinate system The acceleration A _SX and the Y-axis acceleration A _SY are obtained by the following equations (20) and (21), respectively.

  From the equations (20) and (21), the yaw direction attachment angle θy and the pitch direction attachment angle θp are calculated by the following equations (22) and (23), respectively.

  Further, when the vehicle 50 is traveling straight ahead, the equations (22) and (23) are simplified as shown in the following equations (24) and (25), respectively. Using the equations (24) and (25), the yaw direction attachment angle θy and the pitch direction attachment angle θp are obtained.

After the yaw direction mounting angle θy and the pitch direction mounting angle θp are detected, they are converted into Y _B axis accelerations by the following equation (26). From the equation (26), the pitch angle φp is obtained by the following equation (27).

FIG. 20 is a diagram showing a coordinate system used in the third prerequisite technology. In the third base technology, a vehicle body coordinate system shown in FIG. 20 obtained by rotating the X axis of FIG. In the third base technology of the navigation device 51, a one-axis acceleration sensor for example X _S axis, one axis for example, using an angular velocity sensor of the Z _S axis, the pitch direction, the yaw direction, the roll direction all three axes of The mounting angle can be detected. The third prerequisite technique corresponds to the technique disclosed in Patent Document 3 described above.

  In FIG. 20, an arrow indicated by reference numeral “61” represents rotation in the roll direction, which is rotation around the X axis. An arrow indicated by reference numeral “62” represents rotation in the pitch direction, which is rotation around the Y axis. The arrow indicated by the reference sign “63” represents the rotation in the yaw direction, which is the rotation around the Z axis.

In the third base technology, when the longitudinal acceleration becomes zero (0), for example, the output A _SX of the acceleration sensor is used to represent the output A _{SX of the} acceleration sensor when the vehicle 50 stops or travels at a constant speed. _Assuming that A _BX = 0 and A _BY = 0 in the equation (8), the pitch direction mounting angle θp is calculated by the following equation (28).

The longitudinal acceleration _AX-GPS is obtained from the amount of change in the GPS position when the vehicle 50 is traveling straight on the horizontal plane, and A _BY = 0 in the above equation (8), and the following equation (29): The yaw direction mounting angle θy is calculated. Description of the roll direction mounting angle θr is omitted.

In the navigation device of the fourth prerequisite technology, the same coordinate system as the coordinate system of FIGS. 2 and 3 described later, specifically, the vehicle body coordinate system shown in FIGS. A sensor coordinate system is used. In the fourth base technology, a one-axis acceleration sensor for example X _S axis, one axis for example, using an angular velocity sensor of the Z _S axis, the pitch direction mounted angle θp and the yaw direction mounted angle θy is detected. The fourth prerequisite technique corresponds to the technique disclosed in Patent Document 4 described above.

In the fourth base technology, the X _S axis acceleration acceleration sensor is measured in when the vehicle 50 is traveling in a horizontal plane, the following equation (30) and the equation (31), previously determined estimate for each angular The value A _SX-EST is calculated. Equations (30) and (31) are expressed in terms of voltage in the above-mentioned Patent Document 4, but in the fourth prerequisite technology, as in other prerequisite technologies, they are expressed in acceleration form. ing.

Here, V _SPD is a speed calculated from the pulse signal output from the speed sensor, the omega _BZ, an acceleration calculated from the pulse signal output from the speed sensor, omega _BZ is the angular velocity sensor The measured yaw rate.

The navigation device of the fourth base technology records a plurality of calculated estimated values A _SX-EST and measured values A _SX by the acceleration sensor, and attaches the angle at which the estimated value that most closely matches the measured values is attached in the yaw direction Adopt as a corner. From the estimated value A _{SX-EST of} the X-axis acceleration calculated by the equation (30) based on the yaw direction mounting angle θy and the longitudinal acceleration measured value A _SX measured by the acceleration sensor, the pitch angle φp is It is calculated by the following equation (32).

  21 and 22 are diagrams illustrating an example of the traveling state of the vehicle 50. FIG. For example, when the vehicle 50 travels on a loop bridge or a slope 70 of a three-dimensional parking lot as shown in FIG. 21, the sensitivity of the navigation device mounted on the vehicle 50 is lowered because the detection axis of the angular velocity sensor is inclined. Therefore, there is a problem that the position indicated by the reference numeral “72” is erroneously detected as the position of the vehicle 50, not the original position indicated by the reference numeral “71”.

  On the other hand, if the following formula (33) is used, the decrease in the sensitivity of the yaw angle can be corrected. Thereby, for example, even if the vehicle 50 travels on a slope 75 as shown in FIG. 22, the position of the vehicle 50 can be detected with high accuracy.

However, in the acceleration sensor whose detection axis is inclined in the yaw direction, the longitudinal acceleration is attenuated according to the yaw direction mounting angle θp and is affected by the lateral acceleration, that is, centrifugal force, as shown in the characteristic (1). As a result, the pitch angle φ _Hp cannot be correctly measured from the acceleration sensor.

  If the inaccurate pitch angle is used to correct the decrease in the sensitivity of the yaw angle, when the vehicle 50 travels on the loop bridge or the slope 70 of the multilevel parking lot as shown in FIG. There is a problem that arises. In order to solve this problem, it is necessary to detect the mounting angle in the yaw direction.

  Further, the automatic detection performance of each mounting angle in the pitch direction and the yaw direction is determined by the configuration of the sensor built in the navigation device. For example, when a three-axis acceleration sensor and a three-axis angular velocity sensor are provided, the three-axis sensor measurement value necessary for detecting the three-axis mounting angle can be used from the above characteristic (2). The higher the performance, the higher the price.

  In contrast, a so-called low-priced navigation device that cannot use a three-axis acceleration sensor and a three-axis angular velocity sensor does not have a sensor measurement value of a detection axis that is not provided, but is approximately 45 ° or less in both the pitch direction and the yaw direction. The user is required to be able to cope with the mounting angle.

  In the navigation device of the first and second premise technologies described above, it is necessary to provide an acceleration sensor having two or more axes, so that it can be used as an inexpensive navigation device that uses only one-axis acceleration and one-axis angular velocity sensors. Can not.

  Further, in the navigation device of the above-mentioned third premise technology, the built-in sensors are the uniaxial acceleration sensor and the uniaxial angular velocity sensor, but it is possible to detect the mounting angles of all three axes. However, in the third base technology, the pitch direction mounting angle θp is calculated without considering the above-described characteristic (4).

  The formula used in the third premise technique is a calculation formula for detecting the pitch direction mounting angle θp when the vehicle 50 is stopped on a horizontal plane. The third premise technique does not consider a method of detecting a horizontal plane on an actual road or parking lot where various inclination angles exist. Therefore, there is a problem that the detection error of the pitch direction mounting angle θp becomes large, and the accuracy of the yaw direction mounting angle θy calculated using the pitch direction mounting angle θp is not sufficient.

  In the navigation devices according to the first to third base technologies, since the mounting angle is detected only when the vehicle 50 is traveling on the horizontal plane, it is determined whether or not the vehicle 50 is traveling on the horizontal plane. The determination accuracy affects the detection accuracy of the mounting angle, and is a major factor that ultimately determines the position accuracy of the vehicle 50.

  Further, the navigation device of the above-mentioned fourth premise technology includes only a uniaxial acceleration sensor and a uniaxial angular velocity sensor as sensors, as in the third premise technology. In the fourth base technology, even if the vehicle 50 travels on a road including a slope or a parking lot, it is determined whether or not the vehicle 50 is automatically traveling on a horizontal plane, and the pitch direction attachment angle θp is detected. Detects the yaw-direction mounting angle θy during left-right turn traveling on a horizontal plane.

  However, in the fourth base technology, the difference between the acceleration measured value by the acceleration sensor and the estimated acceleration value is handled for the detection of the yaw direction attachment angle θy. Therefore, if the acceleration sensor has a zero point error equivalent to about 1 ° and temperature fluctuation (drift), the detection accuracy of the yaw direction mounting angle θy may be lowered.

  Therefore, the navigation apparatus of the present invention employs the configuration shown in the following embodiment.

<First Embodiment>
FIG. 1 is a block diagram showing a configuration of a navigation apparatus 1 according to the first embodiment of the present invention. FIG. 1 shows a configuration necessary for measuring the posture of the vehicle body and the inertial force in the configuration of the navigation apparatus 1, and a configuration for realizing functions such as route search and route guidance is omitted.

  The navigation device 1 includes a speed sensor 11, an angular velocity sensor 12, an acceleration sensor 13, a distance measurement unit 14, a yaw angle measurement unit 15, an acceleration measurement unit 16, an acceleration estimation unit 17, an acceleration conversion unit 18, a pitch angle estimation unit 19, and an attachment. A corner detection history creation unit 20, a yaw direction attachment angle detection unit 21, a map data storage unit 22, and a road matching unit 23 are configured.

  The navigation device 1 is configured by a computer, for example, and by executing a control program stored in a memory (not shown), the distance measurement unit 14, the yaw angle measurement unit 15, the acceleration measurement unit 16, and the acceleration estimation unit 17. The functions of the acceleration conversion unit 18, the pitch angle estimation unit 19, the mounting angle detection history creation unit 20, and the yaw direction mounting angle detection unit 21 are realized.

  Speed sensor 11, angular velocity sensor 12, acceleration sensor 13, distance measurement unit 14, yaw angle measurement unit 15, acceleration measurement unit 16, acceleration estimation unit 17, acceleration conversion unit 18, pitch angle estimation unit 19, and creation of attachment angle detection history The unit 20, the yaw direction attachment angle detection unit 21, the map data storage unit 22, and the road matching unit 23 are accommodated in the casing of the navigation device 1. Specifically, a computer that realizes each function described above is housed in a housing.

  The navigation device 1 according to the present embodiment is configured to be mountable on a moving body, for example, a vehicle such as an automobile. When mounted on a vehicle, the navigation device 1 is attached to a vehicle body constituting the vehicle.

  2 and 3 are diagrams showing a coordinate system used in the navigation device 1 according to the first embodiment of the present invention. FIG. 2 is a perspective view showing the vehicle body 10 to which the navigation device 1 is attached. FIG. 3A is a plan view showing the vehicle body 10 to which the navigation device 1 is attached, and FIG. 3B is a right side view showing the vehicle body 10 to which the navigation device 1 is attached. c) is a front view showing the vehicle body 10 to which the navigation device 1 is attached.

In the navigation device 1 of the present embodiment, the vehicle body coordinate system shown in FIG. 2 and the sensor coordinate system shown in FIG. 3 are used. The vehicle body coordinate system shown in FIG. 2 is composed of axes extending in the front-rear direction, the left-right direction, and the up-down direction of the vehicle body 10. The vehicle body coordinate system, the axis extending in the longitudinal direction of the vehicle body 10 is called the X _B axis, a lateral direction of the vehicle body 10, refers to the axis extending in the direction perpendicular to the longitudinal direction of the vehicle body 10 and the Y _B axis, the vehicle body 10 of a vertical direction, an axis extending in the direction perpendicular to the longitudinal direction and the lateral direction of the vehicle body 10 of Z _B axis.

In the vehicle body coordinate system, perpendicular to each other and _{X B-axis} and _{Y B} axis, _{Z B} axis is perpendicular to the _X B -Y _B plane defined by the _{X B} axis and _{Y B} axis. Of the longitudinal direction of the vehicle body 10, the forward direction is the positive direction of the X _B axis. Of the left and right direction of the vehicle body 10, the right direction is a positive direction of the Y _B axis. Of the vertical direction of the vehicle body 10, the downward direction is a positive direction of Z _B axis.

  Here, in the front-rear direction of the vehicle body 10, the front direction refers to a direction that coincides with the front direction of the driver seated in the driver's seat of the vehicle, and the rear direction refers to the driver seated in the driver's seat of the vehicle. The direction that matches the back direction. Of the left and right directions of the vehicle body 10, the left direction refers to the direction corresponding to the left direction of the driver seated in the driver seat of the vehicle, and the right direction refers to the right direction of the driver seated in the driver seat of the vehicle. The direction to match. Of the vertical direction of the vehicle body 10, the upward direction refers to a direction that matches the upward direction of the driver seated in the driver's seat of the vehicle, and the downward direction refers to the downward direction of the driver seated in the driver's seat of the vehicle. The direction to match.

The sensor coordinate system shown in FIG. 3 is a coordinate system indicated by the sensor detection axis. The sensor coordinate system shown in FIG. 3 includes axes extending in the front-rear direction, the left-right direction, and the up-down direction of the casing of the navigation device 1. The sensor coordinate system refers to the axis extending in the longitudinal direction of the housing and X _s axis, a lateral direction of the housing, called the axis extending in the direction perpendicular to the longitudinal direction of the housing and Y _s axis, the housing of a vertical direction, an axis extending in the direction perpendicular to the longitudinal direction and the lateral direction of the casing that Z _s axis. The front-rear direction of the housing is a direction along the traveling direction of the vehicle. The vertical direction of the housing corresponds to the vertical direction of the housing.

The navigation device 1 may be attached to the vehicle body of the vehicle 10 with a case inclined. When the casing of the navigation device 1 is attached with an inclination, the detection axes of the sensors such as the angular velocity sensor 12 and the acceleration sensor 13 are also inclined. In this case, X of the sensor coordinate system corresponding to the detection axis, Y, Z-axis, i.e. _{X S} axis, _{Y S} axis, _{Z S} axis, X of the vehicle body coordinate system, Y, Z-axis, i.e. _{X B-axis,} Y It is inclined with respect to the _B axis and the Z _B axis.

In the following description, the inclination angle of each axis of the sensor coordinate system with respect to each axis of the vehicle body coordinate system is referred to as “mounting angle”. As shown in FIG. 3 (c), as viewed from the front direction of the vehicle body 10, refers to the angle of inclination of the Z _S axis of the sensor coordinate system with respect to the Z _B axis of the vehicle body coordinate system "roll direction attached angle", "θr" Represented by As shown in FIG. 3 (b), as viewed from the right side of the vehicle body 10, refers to the angle of inclination of the X _S axis of the sensor coordinate system with respect to X _B-axis of the vehicle body coordinate system "pitch direction mounted angle", "θp" Represented by As shown in FIG. 3 (a), as viewed from the upper direction of the vehicle body 10, refers to the angle of inclination of the Xs axis of the sensor coordinate system with respect to X _B-axis of the vehicle body coordinate system "yaw direction mounted angle", the "θy" Represent.

  Returning to FIG. 1, the speed sensor 11 outputs a pulse signal corresponding to the moving distance of the vehicle as a signal corresponding to the speed of the vehicle. The speed sensor 11 gives the output pulse signal to the distance measuring unit 14.

The angular velocity sensor 12 is constituted by, for example, a gyro. The angular velocity sensor 12 has a detection axis that detects the angular velocity of the vehicle in the vertical direction of the casing of the navigation device 1 that is its own device as the angular velocity of the vehicle, and outputs a signal corresponding to the angular velocity. Vertical housing corresponds to the vertical direction of the housing as described above, matches the extending direction of the Z _S axis of the sensor coordinate system shown in FIG. 3 described above. Z _S axis of the sensor coordinate system corresponds to the above-described sensing axis.

The angular velocity sensor 12, a vehicle of the angular velocity in the vertical direction of the housing, for detecting the Z _S in the yaw direction is an angular velocity around the axis angular velocity (hereinafter, referred to as a "yaw rate of the Z _S axis"). Specifically, the angular velocity sensor 12, every period predetermined, detecting a yaw rate of the Z _S axis. The angular velocity sensor 12 gives the detected angular velocity to the yaw angle measurement unit 15.

The acceleration sensor 13 has a detection axis for detecting the acceleration of the vehicle in the front-rear direction of the casing of the navigation device 1 as its own device as the acceleration of the vehicle, and outputs a signal corresponding to the acceleration. X _S axis of the sensor coordinate system shown in FIG. 3 described above corresponds to the above-described sensing axis. The acceleration sensor 13, as the acceleration of the vehicle, X _S axis direction of the acceleration extending in the longitudinal direction of the housing (hereinafter, "front-rear direction acceleration of the X _S axis", or simply referred to as "longitudinal acceleration of the X _S axis") Is detected. The acceleration sensor 13 detects the acceleration in the front-rear direction of the Xs axis at predetermined intervals. The acceleration sensor 13 provides the acceleration measurement unit 16 with the detected acceleration, specifically, the Xs-axis longitudinal acceleration.

  The distance measuring unit 14 measures the moving distance of the vehicle. Specifically, the distance measuring unit 14 calculates the moving distance of the vehicle based on the pulse signal given from the speed sensor 11. More specifically, the distance measuring unit 14 calculates the moving distance of the vehicle based on the number of pulse signals output from the speed sensor 11 at each predetermined timing. The distance measuring unit 14 calculates the vehicle speed and the longitudinal acceleration based on the calculated moving distance. The distance measuring unit 14 gives the calculated moving distance, speed, and longitudinal acceleration to the acceleration converting unit 18, the pitch angle estimating unit 19, and the road matching unit 23.

The yaw angle measurement unit 15 measures the yaw angle of the vehicle. Specifically, the yaw angle measurement unit 15, on the basis of the angular velocity applied from the angular velocity sensor 12, calculates a yaw angle of the Z _S axis. The yaw angle measurement unit 15 gives the calculated yaw angle of the Z _S axis to the acceleration estimation unit 17, the acceleration conversion unit 18, and the road matching unit 23.

Acceleration measuring unit 16, based on the acceleration given from the acceleration sensor 13 measures the longitudinal acceleration of the X _S axis. Acceleration measuring unit 16, a longitudinal acceleration of the X _S axis measured, as an acceleration measurement value, gives the acceleration conversion section 18 and the attachment angle detecting history creation section 20.

Acceleration estimating unit 17 moves a given distance from the distance measuring unit 14, the speed, and the longitudinal acceleration, based on the yaw angle of the Z _S axis given from the yaw angle measurement unit 15, the yaw direction detection angle range for inner, estimates the X _S axis acceleration for each angular increment the predetermined. Acceleration estimating unit 17, the X _S axis acceleration for each pre-defined angle in increments estimated, as acceleration estimated value, gives the mounting angle detecting history creation section 20.

The mounting angle detection history creation unit 20 generates _XS- axis acceleration information including one acceleration measurement value given from the acceleration measurement unit 16 and a plurality of acceleration estimation values given from the acceleration estimation unit 17 as a set. Only the latest predetermined number of sets are stored.

  The yaw direction attachment angle detection unit 21 detects the yaw direction attachment angle θy based on the stored information provided from the attachment angle detection history creation unit 20. The yaw direction attachment angle detector 21 gives the detected yaw direction attachment angle θy to the acceleration converter 18.

Acceleration conversion section 18, the acceleration measurement values of X _S axis given from the acceleration measuring unit 16, an acceleration estimated value of Y _S axis and Z _S axis, obtaining the longitudinal acceleration of the X _B axis. The acceleration converting unit 18 gives the obtained _XB axis longitudinal acceleration to the pitch angle estimating unit 19.

Pitch angle estimating unit 19, the moving distance given from the distance measuring unit 14, the speed, and the longitudinal acceleration, the longitudinal acceleration of the X _B axis given from the acceleration conversion section 18, the pitch of such time slope traveling The angle φp is calculated. The pitch angle estimation unit 19 gives the calculated pitch angle φp to the yaw angle measurement unit 15 and the road matching unit 23.

  The map data storage unit 22 is realized by a storage device such as a hard disk drive (abbreviation: HDD) device or a semiconductor memory, for example. The map data storage unit 22 stores map data for roads within a predetermined range. The map data includes linear data and road links represented by coordinate points.

  The road collating unit 23 includes a moving distance, speed, and longitudinal acceleration given from the distance measuring unit 14, a yaw angle φy given from the yaw angle measuring unit 15, and a pitch angle φp given from the pitch angle estimating unit 19. Based on the above, the position of the vehicle is identified on the road link read from the map data storage unit 22.

  According to the navigation device 1 of the present embodiment configured as described above, the yaw direction attachment angle θy can be detected. The zero point correction of the angular velocity sensor 12 and the acceleration sensor 13 and the detection of the pitch direction mounting angle in the present embodiment can be performed by a known method, for example, the method disclosed in Patent Document 4 described above.

  FIG. 4 and FIG. 5 are flowcharts showing the procedure of the posture / inertia force measurement process in the navigation device 1 according to the first embodiment of the present invention. In the posture / inertia force measurement processing, processing related to measurement of the posture and inertia force of the vehicle body is performed. The posture / inertial force measurement process includes a yaw direction attachment angle detection process. The processes of the flowcharts shown in FIGS. 4 and 5 are started at predetermined intervals, and the process proceeds to step a1.

Hereinafter, the flowcharts shown in FIGS. 4 and 5 will be described with reference to FIGS. Figure 6 is a graph showing an example of the estimated value of the X _S axis acceleration. In FIG. 6, the horizontal axis indicates the number of sensor measurements in a predetermined cycle, and the vertical axis indicates the estimated value [m / s ² ] of the Xs axis acceleration. In FIG. 6, the graphs indicated by reference numerals “31” to “39” are obtained when the search angle ranges are +40 deg, +30 deg, +20 deg, +10 deg, 0 deg, −10 deg, −20 deg, −30 deg, −40 deg, respectively. Represents the result.

7 and 8, a method for detecting the yaw direction mounted angle from the standard deviation of the latest advance for determining a few minutes of the estimated value and the measured value of the X _S axis accelerations stored in the history, each of the angle increments the predetermined difference It is a graph which shows. FIG. 8 is an enlarged view of the region 40 shown in FIG. 7 and 8, the horizontal axis indicates the provisional yaw direction mounting angle [deg] when calculating the estimated value of the Xs-axis acceleration, and the vertical axis indicates the standard deviation of the difference between the measured value and the estimated value [ m / s ² ].

Figure 9 is a graph showing the measured value and the estimated value of the X _S axis acceleration. In FIG. 9, the horizontal axis indicates the number of sensor measurements in a predetermined cycle, and the vertical axis indicates the measured value [m / s ² ] and estimated value [m / s ² ] of the Xs axis acceleration. In FIG. 9, the graph indicated by the reference symbol “41” indicates the measured value of the Xs-axis acceleration, and the graph indicated by the reference symbol “42” indicates the estimated value of the Xs-axis acceleration.

Figure 10 is a graph showing X _B axis acceleration converted from the measured values of the X _S axis acceleration, and an example of X _B axis acceleration by the speed sensor. 10, the horizontal axis represents the number of sensor measurement period predetermined, vertical axis, the measured value of Xs-axis acceleration ^[m / s 2], the conversion value of _{X B} axis acceleration [m ^{/ s} 2], and The longitudinal acceleration [m / s ² ] by the pulse signal is shown. 10, the graph indicated by reference numeral "43" indicates a measured value of Xs-axis acceleration, the graph indicated by reference numeral "44" indicates the conversion values of X _B axis acceleration, the reference numeral "45" The graph shown by shows the longitudinal acceleration by a pulse signal.

  In step a1, the road matching unit 23 determines whether initialization is necessary. If it is determined in step a1 that initialization is necessary, the process proceeds to step a2, and if it is determined that initialization is not necessary, the process proceeds to step a3.

  In step a2, the road matching unit 23 initializes the posture / inertia force measurement process. Specifically, the measured value, estimated value, and calculated value related to the posture / inertial force measurement process are returned to the values set as initial values. After initialization, the process proceeds to step a3.

  In step a3, the distance measuring unit 14 measures the moving distance, the speed, and the longitudinal acceleration. Specifically, the distance measuring unit 14 multiplies the number of pulse signals measured in this measurement cycle by a coefficient converted to the distance to calculate the moving distance, calculates the speed from the differential of the moving distance, The longitudinal acceleration is calculated from the derivative of. When the moving distance, speed, and longitudinal acceleration are measured, the process proceeds to step a4.

In step a4, the yaw angle measurement unit 15 measures the yaw angle. Specifically, the yaw angle measurement unit 15 calculates the yaw angle of the sensor coordinate system by subtracting the angular velocity zero point separately detected from the Z _S- axis angular velocity output from the angular velocity sensor 12. When the yaw angle is measured, the process proceeds to step a5.

In step a5, the acceleration measuring unit 16 measures acceleration. Specifically, the acceleration measuring section 16 measures the X _S axis acceleration acceleration sensor 13 is outputted as the longitudinal acceleration of the sensor coordinate system. When the acceleration is measured, the process proceeds to step a6 in FIG.

  Steps a6 to a10 in FIG. 5 are processes for detecting the yaw direction mounting angle. In step a6, the acceleration estimation unit 17 determines whether or not the pitch direction attachment angle is detected. If it is determined in step a6 that the pitch direction mounting angle is detected, the process proceeds to step a7. If it is determined that the pitch direction mounting angle is not detected, the pitch angle cannot be calculated. All processing procedures are terminated.

In step a7, the acceleration estimation unit 17 estimates acceleration. Specifically, as shown in FIG. 6, the acceleration estimation unit 17 measures the speed and longitudinal acceleration measured by the distance measurement unit 14 and the yaw angle measurement unit 15 for the search angle range of the yaw direction attachment angle. by using the yaw angle, estimated using the X _S axis acceleration a _S-ESTi based on the angle and the pitch direction mounted angle for each angle increment the predetermined, the formula (34) shown below formula and (35) To do. When the acceleration is estimated in step a7, the process proceeds to step a8.

In Formula (34), A _SPD is the longitudinal acceleration [m / s ² ] measured by the distance measuring unit 14, and A _BY-EST is the lateral acceleration [m / s ² ] obtained by Formula (30). , G is the gravitational acceleration (constant) [m / s ² ].

In the formula (35), each mounting angle used in C _BS, the pitch direction mounted angle theta] p, the yaw direction mounted angle [theta] y, and a roll direction attached angle [theta] r. The pitch direction mounting angle θp is an angle set separately. The yaw direction attachment angle θy is a designated angle i within the angular range of the yaw direction attachment angle, and is designated at a predetermined angular step interval. The roll direction mounting angle θr is zero (0).

In step a8, the mounting angle detection history creating unit 20 creates a history. Specifically, the attachment angle detection history creation section 20, for each of the angle pivot predetermined defines the X _S axis acceleration information for a plurality of acceleration estimated value and the one acceleration measurement set latest advance Store only the number of pairs. As a guide, the history creation timing and the history size are adjusted so that a predetermined number of histories can be created when a right or left turn is made once. When a history is created in step a8, the process proceeds to step a9.

  In step a9, the mounting angle detection history creating unit 20 determines whether or not the number of created histories is equal to or greater than a predetermined number. In step a9, when the history storage number is equal to or greater than the predetermined number, the process proceeds to step a10. When the history storage number is less than the predetermined number, the yaw direction mounting angle cannot be newly detected, so step a11. Migrate to

In step a10, the yaw direction attachment angle detector 21 performs a yaw direction attachment angle detection process. Specifically, the yaw direction mounted angle detecting unit 21, as shown in FIGS. 7 and 8, the X _S axis, each angle obtained by calculating the estimated value of the acceleration, the measurement value of the estimated value of the acceleration and the acceleration The standard deviation of the difference is obtained, and the angle used for calculating the estimated value of the acceleration at which the standard deviation of the difference is the minimum σ _min is adopted as the mounting angle in the yaw direction.

  As shown in FIGS. 7 and 8, when the yaw direction mounting angle is not detected, the standard deviation of the difference between the estimated acceleration value and the measured acceleration value is calculated every 5 °. If the left and right standard deviations are larger than the angle with the smallest standard deviation, the mounting angle in the yaw direction has been detected, that is, it has been detected, but only either the left or right standard deviation has increased. The yaw direction mounting angle is not detected, that is, remains undetected.

  When the yaw direction mounting angle has been detected, the standard deviation of the difference between the estimated acceleration value and the measured acceleration value is incremented by 1 ° for a range of ± 5 ° centered on the detected yaw direction mounting angle. In the same manner as described above, the yaw direction mounting angle is detected and updated by a predetermined method. When the yaw direction mounting angle detection process is performed in step a10, the process proceeds to step a11.

  In step a11, the acceleration conversion unit 18 determines whether or not the yaw direction attachment angle is detected. If it is determined in step a11 that the yaw direction mounting angle is detected, the process proceeds to step a12 to estimate the pitch angle, and if it is determined that the yaw direction mounting angle is not detected, Since the pitch angle cannot be estimated, all processing procedures are terminated.

In step a12, the acceleration conversion unit 18 converts acceleration. Specifically, the acceleration conversion unit 18 uses the pitch direction mounting angle that is set separately and the yaw direction mounting angle detected by the yaw direction mounting angle detection unit 21, and formulas (34) and (35) _{Y S} axis in the estimated acceleration estimated value of _{Z S} axis, from the acceleration measurement values of _{X S} axis, by the equation (37) equation (36) shown below to calculate the _{X B} axis acceleration shown in FIG. 10 .

In Expression (36), A _SX is a longitudinal acceleration measurement value [m / s ² ] measured by the acceleration sensor 13, and A _SY-EST is a lateral acceleration [m / s ² ] obtained by Expression (35). A _SZ-EST is the vertical acceleration [m / s ² ] obtained by the equation (35).

In the formula (37), each mounting angle used in C _SB, the pitch direction mounted angle theta] p, the yaw direction mounted angle [theta] y, and a roll direction attached angle [theta] r. The pitch direction mounting angle θp is a separately set pitch direction mounting angle, the yaw direction mounting angle θy is the yaw direction mounting angle detected in step a10, and the roll direction mounting angle θr is zero (0). .

In step a13, the pitch angle estimation unit 19 estimates the pitch angle. Specifically, the pitch angle estimator 19 calculates the pitch angle from the X _B axis acceleration conversion value A _BX of the acceleration conversion process 8 and the longitudinal acceleration A _SPD of the distance measurement unit 14 by the following equation (38). By calculating, the pitch angle is estimated. When the pitch angle is estimated in step a13, all processing procedures are terminated.

In the present embodiment, an example of a method for detecting the attachment angle in the yaw direction when the uniaxial acceleration sensor having only the _XS axis is provided has been described. However, the present invention is not limited to such a configuration. Figure 11 is a graph showing the measured value and the estimated value of Y _S axis acceleration. FIG. 12 is a graph showing measured values and estimated values of Z _S- axis acceleration.

In FIG. 11, the horizontal axis indicates the number of sensor measurements in a predetermined cycle, and the vertical axis indicates the measured value [m / s ² ] and estimated value [m / s ² ] of the Ys axis acceleration. In FIG. 11, the graph indicated by the reference symbol “46” indicates the measured value of the Ys-axis acceleration, and the graph indicated by the reference symbol “47” indicates the estimated value of the Ys-axis acceleration.

In FIG. 12, the horizontal axis represents the number of sensor measurements in a predetermined cycle, and the vertical axis represents the measured value [m / s ² ] and estimated value [m / s ² ] of the Zs-axis acceleration. In FIG. 12, the graph indicated by reference sign “48” indicates the measured value of the Zs-axis acceleration, and the graph indicated by reference sign “49” indicates the estimated value of the Zs-axis acceleration.

In addition to the Xs axis, when including the acceleration sensor of the Y _S axis or Z _S also biaxial axis or Y _S axis and Z _S also triaxial axis, the measurement value of Y _S axis acceleration shown in FIG. 11 one example of and estimates, and as an example of the measured value and estimated value of Z _S axis acceleration shown in FIG. 12, similarly to the X _S axis, the acceleration of the Y _S axis and Z _S axis can be estimated, respectively . Therefore, using the axis other than the X _S axis, it may be detected yaw direction mounted angle, also using all are equipped axis may detect yaw direction mounted angle.

  In the present embodiment, the yaw direction mounting angle is roughly detected in 5 ° increments for the entire yaw direction mounting angle range, and then the predetermined yaw direction mounting angle range centered on the detected angle is 1 °. The yaw direction mounting angle is detected in detail in increments. However, the present invention is not limited to this, and a predetermined yaw direction mounting angle range from the end of the entire yaw direction mounting angle range may be detected in increments of 1 ° from the beginning. Further, the detection resolution may be further increased.

  In the present embodiment, the history creation timing and the history size are adjusted so that a predetermined number of sets of attachment angle detection histories can be created when a right or left turn is performed once. However, the present invention is not limited to this, and it may be adjusted according to the detection state of the yaw direction mounting angle. Furthermore, the history may be initialized in the following cases (A) and (B) in which the risk of a decrease in the detection accuracy of the yaw direction mounting angle increases.

  (A) When two or more minimums are confirmed within the search angle range of the yaw direction mounting angle.

  (B) When the pitch angle is equal to or greater than a predetermined angle.

  Further, in the present embodiment, the coordinate transformation matrix of the above formulas (1) to (4) based on Euler angles (roll, pitch, yaw) is used. However, coordinate transformation using a quaternion may be performed.

  As described above, according to the present embodiment, the history for the latest predetermined number of sets is created by the mounting angle detection history creating unit 20, and the yaw direction mounting angle is detected based on the created history of each set. The yaw direction mounting angle θy is detected by the unit 21. Accordingly, the yaw direction attachment angle θy can be detected using the acceleration sensor 13 having a single detection axis and the angular velocity sensor 12 having a single detection axis. In particular, in the present embodiment, the yaw direction attachment angle θy can be detected in a range where both the pitch direction attachment angle θp and the yaw direction attachment angle θy are 45 ° or less.

  Further, in the present embodiment, in the search angle range of the yaw direction attachment angle θy, the angle at which the standard deviation of the difference between the acceleration estimated value and the acceleration measurement value becomes the minimum is the yaw direction attachment angle θy, which corresponds to about 1 °. It is difficult to be affected by zero point error and temperature fluctuation (drift). Even if there is a gentle road inclination, the yaw direction attachment angle θy can be detected.

  Thus, in the present embodiment, since the yaw direction attachment angle θy can be detected, even when the casing of the navigation device 1 is attached to the vehicle body inclined in the pitch direction and the yaw direction, By correcting the influence of the other axis acting on the output of each sensor, the posture angle, the inertial force, and the like can be measured with high accuracy.

  In particular, in the present embodiment, the mounting angle detection history creating unit 20 sets a plurality of acceleration estimated values estimated by the acceleration estimating unit 17 and one acceleration measured value measured by the acceleration measuring unit 16 as one set. Then, the history for the latest predetermined number of sets is created. Based on this history, the yaw direction mounting angle detector 21 detects the yaw direction mounting angle θy. Therefore, the navigation device 1 capable of detecting the yaw direction attachment angle θy can be realized with a simple configuration.

  In the present embodiment, the acceleration estimation unit 17 uses the speed and longitudinal acceleration measured by the distance measurement unit 14, the yaw angle measured by the yaw angle measurement unit 15, and the gravitational acceleration. The longitudinal acceleration at the mounting angle selected as the mounting angle of the housing in the direction and the yaw direction is estimated. Thus, if limited to a substantially flat place, the triaxial acceleration at an arbitrary mounting angle can be estimated using the speed sensor 11 and the angular velocity sensor 12. Therefore, by finding an acceleration estimated value that matches the acceleration measurement value for the acceleration of an arbitrary axis, the yaw direction attachment angle θy can be detected from the angle used to calculate the acceleration estimated value.

  Further, in the present embodiment, the yaw direction attachment angle detection unit 21 has the standard deviation of the difference between the estimated acceleration value and the measured acceleration value in the direction in which the attachment angle increases within the search angle range of the yaw direction attachment angle. If it becomes smaller as the mounting angle becomes smaller or the mounting angle becomes smaller, the search angle range is moved in the direction where the standard deviation becomes smaller. In addition, the yaw direction mounting angle detection unit 21 has an angle at which the standard deviation is minimum except at both ends within the search angle range, and goes in both the direction in which the mounting angle is larger and the direction in which the mounting angle is smaller than the minimum angle. Accordingly, when the standard deviation increases, the minimum angle is determined to be the minimum.

  As a result, for the search range of the yaw direction mounting angle, the direction in which the yaw direction mounting angle θy is present can be determined from the tendency of the standard deviation of the difference between the acceleration estimated value and the acceleration measured value for each predetermined angular increment. That is, the search range of the yaw direction mounting angle can be searched and specified without the user's operation.

  Further, in the present embodiment, the acceleration estimation unit 17 estimates the acceleration for each angle larger than a predetermined angle when the yaw direction attachment angle is not detected, and detects when the yaw direction attachment angle is detected. For the search angle range centered on the yaw direction mounting angle, the acceleration is estimated for each angle smaller than a predetermined angle.

  Thus, the search range and the search resolution can be changed according to the detection state of the yaw direction attachment angle θy, so that the initial detection can be performed quickly. Further, the detection resolution can be reduced step by step each time the number of detections increases. In addition, the detection processing load can be reduced.

  Further, in the present embodiment, the acceleration estimation unit 17 estimates three-axis accelerations in the front-rear direction, the left-right direction, and the vertical direction of the casing of the navigation device 1. The pitch angle estimator 19 is measured by the estimated value of the triaxial acceleration estimated by the acceleration estimator 17, the velocity and the longitudinal acceleration measured by the distance measuring unit 14, and the yaw angle measuring unit 15. The yaw angle and the pitch direction mounting angle are used to estimate the longitudinal acceleration when the mounting angles of each axis are all 0 °, and the pitch angle is estimated from the estimated values of the triaxial acceleration.

  With this configuration, the triaxial acceleration at an arbitrary mounting angle can be estimated using the velocity sensor 11 and the angular velocity sensor 12, so that the acceleration is converted into the longitudinal acceleration that is not affected by the lateral acceleration. Thus, an accurate pitch angle φp can be calculated. Thereby, the yaw angle φy of the horizontal plane can be calculated more accurately. Accordingly, it is possible to avoid a decrease in detection accuracy of the position of the vehicle due to the yaw direction mounting angle θy and an erroneous matching.

  In the present embodiment, the mounting angle detection history creating unit 20 creates a history every time the vehicle turns more than a predetermined angle, and the history is determined in advance when the vehicle makes one left or right turn. All sets are stored. As a result, the yaw direction attachment angle θy can be detected from a single right / left turn, so that the initial detection can be performed quickly. Moreover, the detection accuracy of the yaw direction mounting angle θy can be increased every time the vehicle turns left or right. Therefore, the detection accuracy of the position of the vehicle can be quickly made good.

  In the present embodiment, the mounting angle detection history creation unit 20 determines that the yaw direction mounting angle detection unit 21 determines that there are two or more local minimums in the yaw direction search range, and the pitch angle estimation unit 19. In at least one of the cases where the pitch angle estimated by the above becomes larger than a predetermined value, the history is deleted. As a result, it can be seen from the history that the yaw direction mounting angle θy cannot be detected correctly, so that the yaw direction mounting angle θy can be prevented from being detected in a situation where the detection accuracy decreases. Therefore, erroneous detection of the yaw direction attachment angle θy can be reduced.

  In the present embodiment, when the acceleration sensor 13 is an acceleration sensor having two or more axes, for example, the acceleration sensor 13 includes the acceleration in the horizontal direction of the casing of the navigation device 1 and the acceleration in the vertical direction along with the longitudinal acceleration. In the case of a biaxial or triaxial acceleration sensor that measures at least one of the yaw direction attachment angle detection unit 21, the yaw direction attachment angle θy detected for each detection axis coincides with the yaw direction attachment angle. The angle θy is adopted.

  That is, the yaw direction attachment angle detection unit 21 detects the yaw direction attachment angle for the detection axis capable of measuring the longitudinal acceleration, and the difference between the acceleration measurement value and the acceleration estimation value is equal to or less than a predetermined value. When the detected angles in the direction match, the angle is determined as the yaw direction mounting angle. Accordingly, the reliability of the yaw direction mounting angle θy is improved, so that the yaw direction mounting angle θy can be detected with higher accuracy.

  Further, when the difference between the estimated value and the measured value becomes large when the yaw direction mounting angle θy is known, it can be determined that the vehicle is traveling on a slope, so that after the yaw direction mounting angle θy is detected, the horizontal state It can be determined more accurately whether or not. This makes it possible to update the yaw direction attachment angle θy to a more accurate value each time it is detected.

<Second Embodiment>
FIG. 13 is a block diagram showing a configuration of the navigation device 2 according to the second embodiment of the present invention. The navigation device 2 is similar to the navigation device 1 of the first embodiment described above, and includes a speed sensor 11, an angular velocity sensor 12, an acceleration sensor 13, a distance measurement unit 14, a yaw angle measurement unit 15, an acceleration measurement unit 16, and an acceleration. An estimation unit 17, an acceleration conversion unit 18, a pitch angle estimation unit 19, a mounting angle detection history creation unit 20, a yaw direction mounting angle detection unit 21, a map data storage unit 22, and a road matching unit 23 are configured.

  The navigation device 2 of the present embodiment has the same configuration as the navigation device 1 of the first embodiment, but includes an acceleration estimation unit 17 related to yaw direction mounting angle detection, a mounting angle detection history creation unit 20 and a yaw direction. The operation of the direction attachment angle detector 21 is different. Therefore, in the present embodiment, description of the same parts as those of the first embodiment will be omitted, and different parts will be described.

  The mounting angle detection history creation unit 20 includes an acceleration measurement value measured by the acceleration measurement unit 16, a speed and longitudinal acceleration measured by the distance measurement unit 14, and a yaw angle measured by the yaw angle measurement unit 15. As a set, the latest predetermined number of histories are created.

  After the history is created by the mounting angle detection history creating unit 20, the acceleration estimating unit 17 sets each history set for the search angle range of the yaw direction mounting angle according to the estimation condition designated by the yaw direction mounting angle detecting unit 21. For each predetermined angle increment, the acceleration of the arbitrary detection axis corresponding to the angle and the pitch direction mounting angle is estimated. The estimation conditions are a search angle range, a search resolution, a detection axis, and the like.

  The yaw direction attachment angle detection unit 21 gives an acceleration estimation condition to the acceleration estimation unit 17 according to the detection state of the yaw direction attachment angle, and for each angle at which the acceleration estimation value of the acceleration estimation unit 17 is calculated, an acceleration estimation value. The standard deviation of the difference between the measured value and the acceleration measurement value is obtained, and the angle used to calculate the estimated acceleration value at which the standard deviation of the difference is minimized is set as the yaw direction mounting angle.

  FIG. 14 and FIG. 15 are flowcharts showing the processing procedure of the posture / inertia force measurement processing in the navigation device 2 according to the second embodiment of the present invention. The processes of the flowcharts shown in FIGS. 14 and 15 are started at predetermined intervals, and the process proceeds to step b1.

  14 and FIG. 15 are the same as steps a1 to b5 and steps a11 to a13 in the flowcharts shown in FIGS. 4 and 5 described above. Therefore, explanation is omitted. When the acceleration is measured in step b5 in FIG. 14, the process proceeds to step b6 in FIG.

  Steps b6 to b10 are processes for detecting the yaw direction mounting angle. In step b6, the mounting angle detection history creating unit 20 creates a history.

  Specifically, the mounting angle detection history creation unit 20 performs the acceleration measurement value measured by the acceleration measurement unit 16 and the speed and longitudinal acceleration measured by the distance measurement unit 14 every time a predetermined angle turns. Then, the yaw angle measured by the yaw angle measurement unit 15 is taken as one set, and the history for the latest predetermined number of sets is created. As a guide, the history creation timing and the history size are adjusted so that a predetermined number of histories can be created when a right or left turn is made once. When a history is created in step b6, the process proceeds to step b7.

  In step b7, the acceleration estimation unit 17 determines whether or not the pitch direction attachment angle is detected. If it is determined in step b7 that the pitch direction mounting angle is detected, the process proceeds to step b8. If it is determined that the pitch direction mounting angle is not detected, the pitch angle cannot be calculated. Therefore, all processing procedures are completed.

  In step b8, the attachment angle detection history creation unit 20 determines whether or not the number of created histories is equal to or greater than a predetermined number. If it is determined in step b8 that the history storage number is greater than or equal to the predetermined number, the process proceeds to step b9, and if it is determined that the history storage number is less than the predetermined number, a new yaw direction attachment angle is set. Therefore, the process proceeds to step b11.

  In step b9, the acceleration estimation unit 17 estimates acceleration. Specifically, the acceleration estimation unit 17 uses the stored information of each set of history for the search angle range of the yaw direction attachment angle in accordance with the estimation condition specified by the yaw direction attachment angle detection unit 21, for each predetermined angle increment. The acceleration of the arbitrary detection axis corresponding to the angle and the pitch direction mounting angle is estimated as shown in FIG. When the acceleration is estimated in step b9, the process proceeds to step b10.

In step b10, the yaw direction attachment angle detector 21 performs a yaw direction attachment angle detection process. Specifically, the yaw direction attachment angle detection unit 21 gives the acceleration estimation condition to the acceleration estimation unit 17 according to the detection state of the yaw direction attachment angle, and calculates the estimated acceleration value estimated by the acceleration estimation unit 17. For each angle, the standard deviation of the difference between the estimated acceleration value and the measured acceleration value is acquired. Then, as shown in FIGS. 7 and 8, employing the angle used in the calculation of the acceleration estimate the standard deviation of the differences is minimum for X _S axis as yaw direction mounted angle.

  When the yaw direction attachment angle detection process is performed in step b10, the process proceeds to step b11. And in step b11-step b13, the process similar to step a11-step a13 of the flowchart shown in above-mentioned FIG. 4 and FIG. 5 is performed.

In the present embodiment, as in the first embodiment described above, the following may be performed. For example, in the case including the acceleration sensor of the Y _S axis or Z _S also biaxial axis or Y _S axis and Z _S also triaxial axis, using the axes other than the X _S axis, a yaw direction mounted angle Alternatively, the yaw direction mounting angle may be detected using all the provided axes.

  Further, after the yaw direction mounting angle is roughly detected for the entire range of yaw direction mounting angles, the yaw direction mounting angle may be detected in detail for a predetermined yaw direction mounting angle range centered on the detected angle. Then, the yaw direction mounting angle range determined in advance from the end of the entire yaw direction mounting angle range may be detected in detail from the beginning.

  Further, in the following cases (A) and (B) in which the risk that the detection accuracy of the yaw direction mounting angle is lowered is high, the history may be initialized.

  (A) When two or more minimums are confirmed within the search angle range of the yaw direction mounting angle.

  (B) When the pitch angle is equal to or greater than a predetermined angle.

  Further, in the present embodiment, the coordinate transformation matrix of the above formulas (1) to (4) based on Euler angles is used, but coordinate transformation based on quaternions may be performed.

  According to the second embodiment described above, an effect similar to that of the first embodiment can be obtained. Furthermore, in this embodiment, once the mounting angle detection history is created, the yaw direction mounting angle θy is recalculated by changing the detection angle range of the yaw direction mounting angle θy and the resolution of the search angle many times. It is possible. Therefore, the yaw direction mounting angle θy can be quickly detected with high resolution without making multiple turns.

  The navigation devices 1 and 2 according to the first and second embodiments described above are in-vehicle navigation devices mounted on a vehicle, that is, car navigation devices, but can be mounted on a vehicle. Device) or a mobile terminal device such as a mobile phone, a smartphone, or a tablet terminal device.

  The present invention can be freely combined with each embodiment within the scope of the invention. In addition, any component in each embodiment can be changed or omitted as appropriate.

  1, 2 navigation device, 11 speed sensor, 12 angular velocity sensor, 13 acceleration sensor, 14 distance measurement unit, 15 yaw angle measurement unit, 16 acceleration measurement unit, 17 acceleration estimation unit, 18 acceleration conversion unit, 19 pitch angle estimation unit, 20 mounting angle detection history creation unit, 21 yaw direction mounting angle detection unit, 22 map data storage unit, 23 road matching unit.

Claims (10)

A navigation device that can be mounted on a moving body,
A speed sensor that outputs a pulse signal corresponding to a moving distance of the moving body as a signal corresponding to the speed of the moving body;
An angular velocity sensor having a detection axis for detecting the angular velocity of the moving body in the vertical direction of the casing of the device itself, and outputting a signal corresponding to the angular velocity;
An acceleration sensor that has a detection axis for detecting the acceleration of the moving body in the front-rear direction of the casing of the device, and that outputs a signal corresponding to the acceleration, along the traveling direction of the moving body;
Based on the pulse signal output from the speed sensor, a distance measuring unit that measures the moving distance, speed, and longitudinal acceleration of the moving body;
A yaw angle measurement unit that measures an angular velocity and a yaw angle of the moving body in a direction of a predetermined detection axis for each predetermined timing;
An acceleration measuring unit that measures the acceleration of the moving body in the direction of a predetermined detection axis for each predetermined timing;
The movable body in the direction of the detection axis corresponding to the angle and the mounting angle in the pitch direction of the casing, for each predetermined angular increment, with respect to the search angle range that is the search range of the mounting angle of the casing in the yaw direction An acceleration estimator for estimating the acceleration of
The acceleration measurement value measured by the acceleration measurement unit and the acceleration estimation value estimated by the acceleration estimation unit as a set, or the acceleration measurement value and the velocity and longitudinal acceleration measured by the distance measurement unit And a yaw angle measured by the yaw angle measurement unit as a set, a mounting angle detection history creating unit for creating a history for the latest predetermined number of sets,
Based on the created history of each set, for each angle at which the estimated acceleration value is calculated, a standard deviation of the difference between the estimated acceleration value and the measured acceleration value is obtained, and the standard deviation of the difference is minimal. And a yaw direction attachment angle detection unit that obtains an angle used for the calculation that gives the estimated acceleration value as the attachment angle of the housing in the yaw direction. The mounting angle detection history creating unit includes a plurality of acceleration estimation values estimated by the acceleration estimation unit and one acceleration measurement value measured by the acceleration measurement unit as one set, and the latest predetermined number of sets. Create a history of minutes,
The yaw direction mounting angle detection unit, for each angle for which the acceleration estimated value is calculated based on the history of each set created after the history is created by the mounting angle detection history creation unit, The angle used to calculate the standard deviation of the difference between the estimated acceleration value and the measured acceleration value and give the estimated acceleration value at which the standard deviation of the difference is minimized is the mounting angle of the housing in the yaw direction. The navigation device according to claim 1, wherein the navigation device is obtained as follows. The mounting angle detection history creating unit includes an acceleration measurement value measured by the acceleration measurement unit, a speed and longitudinal acceleration measured by the distance measurement unit, and a yaw angle measured by the yaw angle measurement unit. As one set, create the history for the latest predetermined number of sets,
The acceleration estimation unit is a search angle that is a search range of the mounting angle of the housing in the yaw direction based on the history of each set created after the history is created by the mounting angle detection history creating unit. A navigation apparatus characterized by estimating an acceleration of the moving body in a direction of a detection axis corresponding to an angle and a mounting angle in a pitch direction of the casing for each predetermined angle step.   The acceleration estimation unit uses the velocity and the longitudinal acceleration measured by the distance measurement unit, the yaw angle measured by the yaw angle measurement unit, and the gravitational acceleration, and the pitch direction and the yaw direction in the yaw direction. The navigation apparatus according to any one of claims 1 to 3, wherein the longitudinal acceleration at an attachment angle selected as an attachment angle of the housing is estimated.   The yaw direction mounting angle detection unit has a standard deviation of a difference between the acceleration estimated value and the acceleration measured value within a search angle range of the housing mounting angle in the yaw direction so that the mounting angle increases. When it becomes smaller as it goes or becomes smaller as it goes in the direction in which the mounting angle becomes smaller, the search angle range is moved in the direction in which the standard deviation becomes smaller, and the other than both ends in the search angle range There is an angle at which the standard deviation is minimum, and when the standard deviation increases as going to both the direction in which the mounting angle is larger and the direction in which the mounting angle is smaller than the minimum angle, the minimum angle is The navigation device according to claim 4, wherein the navigation device is determined to be minimal.   The acceleration estimating unit estimates the acceleration for each angle larger than a predetermined angle when the mounting angle of the housing in the yaw direction is not detected, and detects the mounting angle of the housing in the yaw direction. 6. The navigation according to claim 4, wherein the acceleration is estimated for each angle smaller than the predetermined angle with respect to the search angle range centered on the detected mounting angle. apparatus. The acceleration estimation unit estimates three-axis acceleration in the front-rear direction, the left-right direction, and the vertical direction of the housing of the device,
An estimated value of triaxial acceleration estimated by the acceleration estimation unit, a speed and a longitudinal acceleration measured by the distance measurement unit, a yaw angle measured by the yaw angle measurement unit, and a pitch direction attachment angle; And a pitch angle estimator for estimating the longitudinal angle when the mounting angles of all axes are all 0 ° and estimating the pitch angle from the estimated values of the three axes. Item 5. The navigation device according to Item 4. The mounting angle detection history creation unit creates a history every time the mobile body turns more than a predetermined angle,
The navigation apparatus according to any one of claims 1 to 3, wherein when a left turn or a right turn of the mobile body is performed once, all the predetermined number of sets of the history are stored.   The mounting angle detection history creating unit determines whether the pitch angle estimated by the pitch angle estimating unit is determined by the yaw direction mounting angle detecting unit when it is determined that there are two or more local minimums in the yaw direction search range. 6. The navigation device according to claim 5, wherein the history is deleted in at least one of cases where the value is larger than a predetermined value. The acceleration sensor is a biaxial or triaxial acceleration sensor that measures at least one of a longitudinal acceleration and a vertical acceleration along with the longitudinal acceleration,
The yaw direction attachment angle detection unit detects the attachment angle of the housing in the yaw direction with respect to the detection axis capable of measuring the longitudinal acceleration, and the difference is not more than a predetermined value and is detected in each direction. The navigation device according to any one of claims 1 to 3, wherein when the determined angles coincide with each other, the angle is obtained as an attachment angle of the housing in the yaw direction.