JP2005221482A - Direction indicator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direction indicator capable of computing an accurate direction irrespective of destinations, vehicle types, operation conditions of vehicular electrical equipments or the like, and capable of reducing a cost. <P>SOLUTION: A direction of earth magnetism detected by an earth magnetism detecting means is corrected to determine the direction of a vehicle by a direction determination means 1, based on detection information such as the present position of the vehicle, and operation conditions of equipments and the electrical equipments attached to the vehicle, and based on a preliminarily stored correction data. In concretely saying, the direction determination means 1 acquires preliminarily magnetic information generated from the equipments in the periphery of the direction indicator and a vehicle body, generates a directional circle serving as a reference for the direction determination when correcting the direction of earth magnetism, and sets a size range of the directional circle when generating it, in a range fit to a using condition of the vehicle, to determine the direction of the vehicle. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an azimuth indicating device in which a vehicle indicates an azimuth.

In general, an azimuth indicating device is composed of a geomagnetism detection means, an azimuth calculation means, and an output means. The direction of the geomagnetism detected by the geomagnetism detection means is converted into an azimuth by the azimuth calculation means, and display, sound, etc. are output using the output means. (See, for example, Patent Document 1).
In addition, the direction of the geomagnetism detected by the geomagnetism detection means includes an error caused by a different declination for each region, and the direction indicating device needs to correct the direction of the geomagnetism according to the declination of the region to be used. is there. If a correction amount is set in advance according to the declination of the area where the azimuth indicating device is used, an accurate azimuth can be obtained, but if this correction amount is set to a fixed value, movement over a wide range In this case, the error amount due to the declination changes with movement, so that the error becomes large, and the compatibility over each region is lost, so that the versatility is lowered.
In order to solve such problems, there has been proposed a method in which a correction amount input means is provided, and the user who uses the device manually adjusts the correction amount each time. In this case, it is very complicated because the user has to do it manually each time.Therefore, by adding position detection means, storage means, declination correction means, according to the current position detected by the position detection means, A method has been proposed in which correction is automatically performed by a declination correction unit (see, for example, Patent Document 2).

  In addition, considering the case where the azimuth indicating device is mounted on a car, the disturbance of the magnetic field due to the surrounding environment other than the declination cannot be ignored in obtaining highly accurate azimuth information, so as a solution for the disturbance of the magnetic field due to the environment, A method has been proposed in which weighting of data is determined based on the reliability of data obtained from a geomagnetic sensor and reflected in a display orientation (see, for example, Patent Document 3).

JP 2001-289646 A JP-A-62-245111 Japanese Patent Laid-Open No. 5-280988

Although it is possible to correct to some extent the azimuth error detected by the azimuth detecting means by the method proposed in Patent Document 1, in order to obtain high-precision azimuth information in any region of the world, it is mounted on an automobile. The degree of the influence on the direction detection means that the magnetic field generated by the operation status (electrical addition status) of the connected electrical equipment affects the direction detection means depends on the operation status of the electrical equipment and the vehicle equipped with the direction indication device. Since it is determined by the characteristics, there is a problem that it is necessary to perform appropriate correction in consideration of the operation status of various electrical components, the characteristics of the vehicle, and the like.
Further, in the method of correcting based on the dispersion and intensity of the geomagnetic sensor output described in Patent Document 3, not only the declination but also the magnitude (absolute amount) of the geomagnetism (horizontal component) due to the movement of the current position. In addition, the amount of geomagnetism attenuation by the vehicle (ratio of the amount of geomagnetism outside the vehicle compartment and inside the vehicle compartment) varies from vehicle type to vehicle type, so the geomagnetic amount (horizontal component) changes and is greatly affected. There has been a problem that it is necessary to set an evaluation method and various parameters in consideration of the quantity and the attenuation characteristics of each vehicle.

  The present invention has been made to solve the above-described problems, and can accurately calculate the azimuth regardless of the destination, the vehicle type, the operating state of the vehicle electrical components, etc., and can reduce the cost. An object is to obtain an azimuth indicating device.

  The azimuth indicating device according to the present invention corrects the direction of geomagnetism detected based on detection information such as the current position of the vehicle and the operating state of equipment and electrical components mounted on the vehicle, and correction data stored in advance. Is to determine the direction.

  The present invention corrects the direction of the geomagnetism detected by the geomagnetism detection means based on the information detected by the position detection means and the vehicle state information acquisition means, and the correction data stored in the storage means in advance, and thereby determines the direction of the vehicle. Since it is configured to determine, accurate calculation of the azimuth can be performed regardless of the destination, the vehicle type, the operation state of the vehicle electrical components, etc., and the cost can be reduced by sharing.

An embodiment of the present invention will be described below.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing an azimuth indicating apparatus according to Embodiment 1 of the present invention. In the figure, the azimuth determining means 1 is composed of a declination correcting unit 2, a vehicle state correcting unit 3, and a disturbance removing unit 4. The azimuth is determined based on outputs from the position detection means 5, vehicle state information acquisition means 6 and geomagnetism detection means 7, which will be described later. Various correction conditions and arithmetic expressions necessary for determining the azimuth are stored in the storage means 8. Obtain.
The declination correction unit 2 generates parameters (declination and geomagnetism) based on the current position. Specifically, the declination correction unit 2 refers to the storage unit 8 based on the current position information obtained from the position detection unit 5, and An angle correction amount and an absolute amount of geomagnetism (horizontal component) are generated and used for disturbance determination and the like.

The vehicle state correction unit 3 generates parameters based on the vehicle state. Specifically, the vehicle state correction unit 3 refers to the storage unit 8 based on the information obtained from the vehicle state information acquisition unit 6 and depends on the operation state of the in-vehicle device / electrical component. A correction amount and a vehicle running state are generated and used for disturbance determination and the like. It is also possible to generate parameters related to language and design.
The disturbance removing unit 4 generates parameters based on the disturbance state. Specifically, the disturbance removing unit 4 analyzes the information obtained from the geomagnetic detection means 7, the declination correction unit 2, and the vehicle state correction unit 3 to determine the disturbance state. To do. As the determination method of the disturbance state in the disturbance removing unit 4, for example, a conventional method in consideration of the absolute amount of geomagnetism may be used.

  Further, the direction determining means 1 can perform various corrections (filtering and the like), performs various corrections based on information obtained from the declination correction unit 2, the vehicle state correction unit 3 and the disturbance removal unit 4, and determines the direction. The correction information at that time can be, for example, correction due to disturbance (switching the number of leveling, changing the weighting setting, setting hysteresis, setting azimuth resolution, etc.), correction based on the operating state of the in-vehicle device / electrical component, and Examples include declination correction. These correction information are preferably tabulated in advance.

  The position detection means 5 detects the current position, and acquires position information using, for example, a GPS signal or a mobile phone. Since the correction amount of the declination and the absolute amount of the geomagnetism (horizontal component) need only be known, the position detection unit 5 only needs to be able to obtain a rough latitude and longitude. In addition, as long as the position information can be obtained, any in-vehicle device such as navigation, audio, ETC, etc. may be used, or only the initial position is input, and the direction indicating device itself provides direction information and distance information. May be used to calculate the current position. That is, the position detecting means 5 may be any one having a simple navigation function.

The vehicle state information acquisition means 6 detects the operation state of the vehicle and the in-vehicle devices / electrical components mounted on the vehicle, and the following items (1) to (5) can be considered as examples of items to be detected. In the vehicle state information acquisition means 6, information that does not change the state (information of items (1) and (2)) may be preset using the input means 10, for example, an automobile manufacturer, a dealer, etc. Set with.
(1) “Destination information” is information for specifying a region to be used, and examples thereof include a region (EU, etc.) and a country. (2) “Vehicle identification” is information for identifying and specifying a vehicle, and includes, for example, model name, year, body shape, drive system (engine, hybrid), and the like. (3) “Vehicle running state” is information for specifying the vehicle running state (running / stopping), and includes, for example, a key position, a vehicle speed, a shift position, and a steering angle. (4) “In-vehicle device / electrical component operation state” is information for specifying the operation state of various devices mounted on the vehicle. For example, navigation, AV, air conditioning, wiper, turn signal, window, door, Examples include sunroofs, engines, brakes, and lamps. (5) “Ambient environment” is information for specifying the surrounding environment in which the vehicle is traveling, and examples thereof include road conditions (highways and general roads), temperature, and inclination.

The geomagnetism detecting means 7 detects the direction of geomagnetism, and for example, a sensor using a fluxgate type magnetic sensor, a Hall element, a magnetoresistive element or the like is used.
The storage means 8 stores various conditions such as correction formulas and coefficients used when the azimuth determining means 1 determines the azimuth, and is also used for calculating average values and variance values, holding past history information, and the like. . The output means 9 provided on the output side of the orientation determining means 1 is for transmitting the orientation to the user based on information such as the orientation, language, and design determined by the orientation determining means 1, such as display and sound. Any means can be used as long as it can be recognized by the user.

The output means 9 transmits the azimuth to the user based on the information such as the azimuth, language, and design determined by the azimuth determining means 1, and any means may be used as long as the user can recognize the display or voice. . The input unit 10 is used by the user to directly input the current position, correction conditions, and the like. For example, a hard key, a touch panel, a remote controller, voice recognition, and the like can be considered.
The communication means 11 is used to input position information for the position detection means 5 and information such as the above-described vehicle running / stopping and operation status of electrical components to the vehicle state information acquisition means 6. , IrDA, DSRC (Dedicated Short / Rang Communication), wireless communication means such as a mobile phone and PDA, and wired communication means such as an in-vehicle LAN and a dedicated communication line. The input means 10 and the communication means 11 can be installed as necessary.

Next, the operation will be described with reference to FIGS.
First, the main process of FIG. 2 will be described.
Using the microcomputer A / D terminal or the like, the output from the geomagnetic sensor 7, that is, geomagnetic data is acquired (step ST1), and the average value, variance, etc. of the geomagnetic data are created (step ST2). Next, the position data of the vehicle detected by the position detecting means 5 is captured using the communication means 11 or the like (step ST3), and the declination and the geomagnetic quantity are determined based on the captured position data. And a reference for geomagnetism (step ST4). The position data may be input manually.

Next, using the communication means 11 or the like, the vehicle state data detected by the vehicle state information acquisition means 6 is captured (step ST5), and the operating state of the vehicle or electrical component is determined based on the captured vehicle state data. A correction amount is created and corrected (step ST6).
A branch for each operation mode is determined (step ST7), and if the turn correction mode, a one-turn turning correction control as described later is performed (step ST8), and if the direction display mode, a later-described azimuth determination control is performed (step ST8). ST9) When any control is finished, display control is performed (step ST10), and a series of operations is finished. That is, in these steps ST7 to ST10, first, a reference azimuth circle (Lissajous circle) is generated to determine the azimuth, and the azimuth is determined based on the azimuth circle and the azimuth data input while taking into account various correction conditions. The display is performed based on the determined azimuth, and a message is displayed during the round turn correction control, and the azimuth calculation result is displayed during the azimuth determination control.

Here, the operation of the one-turn turning correction control (step ST8) will be described in detail. In the process at the time of the one-turn turning correction, when the azimuth indicating device is used in an in-vehicle application, the direction of the geomagnetism cannot be correctly determined due to the influence of a magnetic field (= magnetization) generated from a device or a vehicle body around the directional indicating device. For this reason, a function for acquiring and correcting magnetization information in advance is required. Obtaining this magnetization information is a one-turn turning correction, and a circle (azimuth circle) serving as a reference for azimuth determination is generated by the following procedure.
First, turning of the vehicle is started, various variables for determination are initialized, and coordinates at the start of turning correction are held. Next, the points on the azimuth circle are evenly sampled by sequentially acquiring the geomagnetic data during the vehicle turning, and the minimum and maximum values of the X / Y coordinates are obtained. This makes the center coordinates clear. Finally, when the predetermined condition is satisfied, that is, when the original turning start point is returned to the original position, it is determined that the sampling is finished, and the center coordinates of the azimuth circle and the diameter in the X / Y direction are generated to generate the azimuth. Determine the circle.

  The azimuth circle generated by this round turn correction becomes the reference for azimuth determination including disturbance removal, and if a correct azimuth circle cannot be generated, a large error will occur in the azimuth determination, but there is an error in the azimuth circle generated by this round turn correction. There are three possible causes: sampling data abnormalities due to disturbances, second abnormalities in the surrounding geomagnetism (geomagnetic decay), and third effects due to operating conditions of the in-vehicle devices and electrical components.

  The sampling data abnormality due to the first disturbance is countered by a technique such as averaging sampling data by a conventional technique. In addition, for the second surrounding geomagnetism abnormality (geomagnetic decay), a range of the size of the azimuth circle is set as a condition for determining the azimuth circle, and the range setting is determined by the strength of the geomagnetism. , It is necessary to set each by the destination. Therefore, in the present embodiment, since the current position and vehicle type can be determined, a range that matches the use conditions is set. As a result, it is possible to generate a highly accurate azimuth circle, and it is possible to share the same for different purposes and destinations. In addition, when the size of the azimuth circle is clearly strange, a message for performing the turning correction in another place is displayed. In addition, with respect to the influence of the operating state of the third in-vehicle device / electrical component, the geomagnetic detection means is affected by the operating state of the in-vehicle device / electrical component, Since an error occurs when the operation state of the electrical component is different, in this embodiment, the difference can be corrected at the time of azimuth determination by determining the operation state of the in-vehicle device or the electrical component. High azimuth determination is possible, and it can be shared for different uses of vehicles, so that the cost can be reduced.

FIG. 3 is a flowchart showing a method of the above-mentioned one-turn turning correction process.
Using the microcomputer A / D terminal or the like, the output from the geomagnetism detecting means 7 is acquired and the minimum value in the X direction is updated (step ST21), the maximum value in the X direction is updated (step ST22), and the Y direction is updated. The minimum value is updated (step ST23), and the maximum value in the Y direction is updated (step ST24). That is, in steps ST21 to ST24, first, the outer shape of the azimuth circle is estimated from the acquired azimuth data, and the diameter and center are obtained from the X coordinate and Y coordinate, and the maximum value and minimum value of each. Here, the obtained diameter and center can be expressed as diameter = maximum value-minimum value and center = (maximum value + minimum value) / 2.

  Next, it is determined whether or not the vehicle has returned to the start position for turning correction (step ST25). If the vehicle has returned, the center and the diameter in the XY direction are calculated (step ST26), and it is determined whether or not the specified number of blocks have been passed. (Step ST27) If the number of blocks has passed the specified number of blocks, the shape and size of the azimuth circle is checked to determine whether it is a normal azimuth circle (step ST28). Here, the size of the azimuth circle is determined by the strength of geomagnetism and the amount of attenuation in the vehicle body. Therefore, if the current position and the vehicle type are known, the size of the normal azimuth circle can be determined. Next, if it is a normal azimuth circle in step ST28, the diameter in the XY direction is stored (step ST29), a turn correction completion flag is set (step ST30), and the flow returns to step ST7 (FIG. 2) to return to the azimuth display mode. Then, the direction determination control process in step ST9 is performed.

  On the other hand, if it is not returned to the start position of the turn correction in step ST25, the bearing block is determined (step ST31), it is determined whether or not the corresponding block has not passed (step ST32), and if the corresponding block has not passed. Then, the number of passing blocks is added (step ST33), and the process returns to step ST21. If the block does not pass, the process returns to step ST21 as it is. If the specified number of blocks has not been passed in step ST27, the process returns to step ST21. If not the normal azimuth circle in step ST28, the azimuth circle determination work is initialized (step ST34), and then the process returns to step ST21.

  Note that the orientation block in step ST31 is an area centered at the start point and divided into 360 degrees by 32. Data acquisition is completed according to the number of orientation blocks passed in order to obtain data evenly from the circumference of the orientation circle. Judging. In addition, by monitoring the vehicle operation state when generating the azimuth circle, it is possible to eliminate the influence of the operation state of the electrical components and create an accurate azimuth circle.

Here, the operation of the direction determination control (step ST9) will be described in detail. In the processing at the time of azimuth determination, the sampled geomagnetic data is converted by the following procedure at the time of azimuth determination.
First, the geomagnetic disturbance (= disturbance) due to the surrounding environment is removed. Various methods can be considered as a method of removing this disturbance. Here, as an example, a method of following a change in direction during turning of the vehicle while suppressing the disturbance component is adopted. Next, azimuth calculation is performed based on the geomagnetic data from which disturbance has been removed, and conversion into azimuth information is performed. Next, the declination is corrected according to the current position, and finally, the display azimuth is determined by converting the azimuth information after declination correction into a display azimuth (for example, 16 azimuths).

By the way, when determining the azimuth, the geomagnetic data is converted into the azimuth based on the reference azimuth circle generated by the round turn correction. However, if the state of the magnetism or the magnetic field generated around the azimuth display device changes, the azimuth calculation is significant. An error is generated.
The cause is firstly a change in the geomagnetic state (deflection angle, geomagnetism) due to movement, and secondly, the magnetism generated around the azimuth indicating device due to the operating state (current load) of the in-vehicle device or electrical component. It is a change of state.
Regarding the change of the geomagnetic state due to the first movement, since the state of the geomagnetism changes depending on the position, a large error occurs in the azimuth calculation when the geomagnetic state changes due to the movement compared to the time of generating the reference azimuth circle. The state (strength) of the geomagnetism is determined from the position information, and various corrections are made in comparison with the geomagnetism when the azimuth circle is generated.

Specifically, first, as a method for determining disturbance, evaluation is performed based on the distribution of geomagnetic sensor data and the distance from the center of the reference azimuth circle, and when making the determination, the shape of the reference azimuth circle (center coordinates and diameter) is extremely high. However, when moving greatly from the point where the azimuth circle is generated, the absolute amount of the horizontal component of the geomagnetism changes, so that the shape of the azimuth circle also changes and correct evaluation cannot be performed. Therefore, in the present embodiment, even if the position of the reference azimuth circle is greatly moved, the center coordinates do not fluctuate greatly unless the vehicle magnetized state is changed. By analogy with this, it becomes possible to always determine the disturbance using the correct azimuth circle.
In addition, it is possible to detect the movement amount from the position information and current position information when the reference azimuth circle is created, and recreate the reference azimuth circle when the movement amount exceeds the predefined range For this reason, if a message prompting execution of turning correction is displayed, it is always possible to make a determination based on the correct azimuth circle.

  In addition, in order to perform the determination under the same conditions even when the geomagnetic state is different, normalization of the output data of the geomagnetism detection means is performed, where normalization means equalization of the geomagnetic sensor output data, Calculates the coefficient required for equalization from the size of the azimuth circle created at the time of turning correction, and refers to the process of multiplying the geomagnetic sensor data output by a coefficient (sensitivity adjustment). As the absolute amount of the horizontal component changes, the size of the azimuth circle also changes, making correct evaluation impossible. Therefore, in the present embodiment, even when moving greatly from the location where the reference azimuth circle is created, only the size of the azimuth circle is required for normalization, so the size of the azimuth circle is estimated from the position information. Thus, normalization can always be performed using a correct coefficient.

  Even under the same disturbance conditions, the ratio of geomagnetism and disturbance (S / N ratio) changes greatly due to the change in geomagnetism. For this reason, thresholds and data used for evaluation are determined by the geomagnetism intensity. Change the number of averaging and weight setting value, but when moving greatly from the point where the azimuth circle is generated, the absolute amount of horizontal component of geomagnetism changes, so the shape of the azimuth circle also changes, and the correct condition should be set Can not be. Therefore, in this embodiment, even when the reference azimuth circle is greatly moved from the place where it was created, the disturbance condition is determined by always applying the correct condition by analogizing the size of the azimuth circle from the position information. It becomes possible.

  Next, regarding the change in the magnetic state that occurs around the direction indicating device due to the operating state of the second in-vehicle device or electrical component, it occurs around the direction indicating device when the current load changes depending on the operating state of the in-vehicle device or electrical component. Since the magnetic state to be changed changes, a large error occurs in the azimuth calculation. Therefore, the magnetic change is determined according to the operation state of the in-vehicle device or the electrical component, and various corrections are performed.

Specifically, in the present embodiment, first, since the magnetic field generation state is known from the operation state information of the in-vehicle device and the electric product mounted on the vehicle, this is corrected. In other words, since the amount and direction of magnetic field generation varies depending on the type of vehicle, information such as vehicle identification and on-board equipment / electrical component operating status is comprehensively determined, and the difference from the state at the time of one-turn turning correction is referred to the storage means. The correction amount is determined by correcting.
In addition, disturbance removal is performed based on vehicle running conditions such as running / stopping, steering angle, etc. In other words, it is possible to detect changes in the direction of the vehicle by using the vehicle type information, etc., depending on the vehicle speed, steering angle, etc., and the direction should not change abruptly while driving straight or at high speeds. Change can be suppressed. In addition, data during operation of a device that operates at a fixed period (for example, a wiper or a winker) can be corrected by changing the setting of the filter processing, such as increasing the number of times of averaging.

FIG. 4 is a flowchart showing how to perform the above-described azimuth determination process.
First, normalization processing is performed (step ST41), the disturbance mixed state is evaluated, and the reliability of geomagnetic data is evaluated to determine the geomagnetic state (step ST42), and various filter processes are performed based on the geomagnetic state determination result. Implementation, that is, filtering processing is performed (step ST43), the azimuth angle is calculated (step ST44), the declination is corrected (step ST45), and the process proceeds to step ST10 (FIG. 2).

Finally, the operation of the azimuth display control (step ST10) will be described.
First, regarding the azimuth accuracy information, information regarding the azimuth accuracy can be obtained by determining a disturbance mixed state or the like using position information or vehicle operation information when determining the azimuth. And based on this accuracy information, the user can easily know the accuracy of the azimuth information by adjusting the resolution of the azimuth to be displayed (8 azimuth ⇔16 azimuth switching) and displaying the reliability.
Further, for vehicle information, by switching display / guide language, unit, and screen design (color arrangement and symbol arrangement) based on destination information, it is not necessary to divide products for each destination.

  As described above, according to the first embodiment, the geomagnetism detected by the geomagnetism detection means based on the information detected by the position detection means and the vehicle state information acquisition means and the correction data stored in the storage means in advance. By correcting the direction of the vehicle and determining the direction of the vehicle, it becomes possible to calculate the correct direction regardless of the destination, vehicle type, operating state of the vehicle electrical components, etc., and the cost can be reduced by sharing Play.

It is a block diagram which shows the azimuth | direction instruction | indication apparatus by Embodiment 1 of this invention. It is a flowchart which shows the content of the main process of the orientation instruction | indication apparatus by Embodiment 1 of this invention. It is a flowchart which shows the content of the one round turning correction | amendment process of the direction instruction apparatus by Embodiment 1 of this invention. It is a flowchart which shows the content of the azimuth | direction determination process of the azimuth | direction direction apparatus by Embodiment 1 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Direction determination means, 2 Deflection correction part, 3 Vehicle state correction part, 4 Disturbance removal part, 5 Position detection means, 6 Vehicle state information acquisition means, 7 Geomagnetic detection means, 8 Storage means, 9 Output means, 10 Input means 11 Communication means.

Claims (4)

  Position detection means for detecting the current position of the vehicle, vehicle state information acquisition means for detecting information related to the vehicle including at least the operation state of the vehicle and the equipment and electrical components mounted on the vehicle, and the current position of the vehicle Geomagnetic detection means for detecting the direction of geomagnetism, storage means for storing correction data for various conditions used in determining the orientation in advance, detection information from the position detection means and vehicle state information acquisition means, and the storage means An azimuth indicating device comprising azimuth determining means for correcting the data related to the direction of geomagnetism detected by the geomagnetism detecting means on the basis of correction data from the vehicle and determining the azimuth of the vehicle.   The azimuth determining means acquires in advance magnetization information generated from a device and a vehicle body around the azimuth indicating device, and corrects the direction of geomagnetism detected by the geomagnetism detection means based on the magnetization information. Item 1. The direction indicating device according to Item 1.   The azimuth determining means generates an azimuth circle that serves as a reference for azimuth determination when correcting the geomagnetic direction, and sets the size range of the azimuth circle at the time of generation within a range that matches the use conditions of the vehicle. The azimuth indicating device according to claim 2, wherein the azimuth is determined.   The azimuth determining means corrects the difference at the time of the azimuth determination when the operation state of the device / electrical component mounted on the vehicle at the time of azimuth determination is different from that at the time of azimuth determination. The azimuth indicating device described.

Images