JP3402105B2 - Positioning device - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to the measurement that is applied to the case of measuring the current position of the moving body by the so-called autonomous navigation
About the place apparatus.

[0002]

2. Description of the Related Art Conventionally, various navigation devices to be mounted on a moving body such as an automobile have been developed. This navigation device is, for example, a C that stores road map data.
It is composed of a large-capacity data storage means such as a DROM, a current position detection means, and a display device for displaying a road map near the detected current position based on the data read from the data storage means. In this case, GPS (Global Positioning Sys
tem) based on a positioning system (hereinafter simply referred to as GPS) that uses a signal transmitted from a positioning artificial satellite, and based on information such as the traveling direction and traveling speed of the vehicle, There is an autonomous navigation method that tracks changes and measures the current position (self-contained navigation).

Then, the data of the road map in the vicinity of the current position detected by the current position detecting means is stored in a CD.
The video signal is read from a large-capacity data storage means such as a ROM, a video signal for displaying a road map is created, and this video signal is supplied to a display device to display a road map near the current position.

By the way, when the current position is measured by the autonomous navigation, the detection accuracy of the sensor for detecting the traveling direction and the traveling speed of the vehicle greatly affects the positioning accuracy. Therefore, to enable accurate positioning,
It is necessary to correct the output of the sensor and calculate the position. As one of the correction process, there is a correction of zero point voltage of the angular velocity sensor. That is, when the direction is not changed
While the output voltage of the angular velocity sensor is referred to as a zero-point voltage, usually angle
The zero-point voltage of the speed sensor has a characteristic that it changes with time.

FIG. 7 is a diagram showing an example of a change state of the zero-point voltage with the passage of time after the direction change disappears, and the zero-point voltage gradually rises with the passage of time. This figure
FIG. 8 shows an example of the correction state when there is a change in the zero-point voltage shown in FIG. 7. As long as the speed sensor continues to detect the stopped state, the zero-point voltage is corrected to the sensor output voltage at that time. Is done.

FIG. 9 is a flow chart showing the determination for performing the conventional correction processing of the zero point voltage. It is determined whether or not the traveling speed is detected from the output of the speed sensor (step 10).
1) When 0 km / h is detected as the traveling speed (that is, when the vehicle stops), a correction process for changing the zero-point voltage based on the sensor output at that time is started (step 10).
2). By performing the correction processing of the zero-point voltage in this way, it is possible to prevent erroneous detection in which a change in azimuth is detected while the vehicle is stopped.

[0007]

In a vehicle such as an automobile, the direction of the vehicle may change while the vehicle is not running, such as a turntable installed at the entrance of a parking lot. Here, the above-mentioned angular velocity with the vehicle stopped
If the zero point voltage of the degree sensor is corrected, the azimuth is actually changed, but the azimuth change is regarded as a zero point voltage change, and the wrong azimuth is detected. A large positioning error will occur in the azimuth.

FIG. 10 shows the angular velocity ω _X detected from the output of the angular velocity sensor (azimuth sensor) when a vehicle equipped with a conventional positioning device by autonomous navigation is placed on a turntable and rotated 180 °, and It shows the relationship with the direction S _X detected by the autonomous navigation based on the output.
When the turntable starts to rotate, a predetermined angular velocity is detected by the angular velocity sensor, but the angular velocity is corrected to 0 by the zero point voltage correction. Therefore, as the azimuth S _X to be judged, a slight azimuth change is detected when the turntable starts rotating, but an azimuth change returning to the original direction is detected at the angular velocity when the turntable stops, and the azimuth eventually ends up being detected. It is determined that there is almost no change, and the azimuth for which positioning is performed will be completely different from the actual azimuth.

In addition to the case where the vehicle is forcibly rotated by the turntable or the like as described above, the case where the direction of the vehicle is repeatedly changed at a very low speed such as when entering or leaving the garage is repeated. , The azimuth may gradually shift greatly. This is because it is difficult to distinguish between running at ultra-low speed and stopped state from the output of the speed sensor, and the azimuth change during ultra-low speed travel is corrected as a zero point voltage fluctuation error of the angular velocity sensor.

In view of the above points, an object of the present invention is to enable correct azimuth detection by an angular velocity sensor when stopped or when traveling at an extremely low speed when positioning by autonomous navigation.

[0011]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a method for detecting the angular velocity sensor when it is determined that the vehicle is not moving based on the output of the angular velocity sensor, when the traveling speed is detected to indicate that the vehicle is stopped. The azimuth change due to the output is corrected.

According to the present invention, only when it is judged from the output of the angular velocity sensor whether or not the vehicle is moving, and when it is judged from both judgments that the vehicle is in the stopped state, By correcting the azimuth change, it is possible to correctly correct only the fluctuation of the sensor output at the time of stop.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
It will be described with reference to to 6.

In this example, the present invention is applied to a navigation device mounted on a vehicle which is a moving body (here, it is an automobile), and its entire structure is shown in FIG.

The structure of the navigation device of this embodiment will be described below with reference to FIG. 1. A GPS antenna 11 is connected to the navigation device 10, and a signal received by this antenna 11 is processed by GPS signal processing. Part 12
Supply to. In the GPS signal processing unit 12, the GPS (Glob
al Positioning System) for receiving the positioning system. That is, the GPS positioning signal transmitted from a plurality of positioning satellites is received, the data included in the signal is analyzed, and the current position (latitude, longitude, altitude) is received.
Get the data of. The current position data obtained by the GPS signal processing unit 12 is supplied to the system controller 13.

The system controller 13 is a controller for controlling the display of a road map in the vicinity of the measured current position, and corresponds to the CD ROM control unit 14 when the positioning data of the position is obtained from the GPS signal processing unit 12. Send a command to read the road map near the position. CD
The ROM control unit 14 controls reading of map data from a CD ROM (here, it is a map disk on which road map data is recorded) 16 mounted on a CD ROM driver 15, and reads the read map data. , Memory 17 connected to the system controller 13.

The road map data stored in the map disk 16 is composed of, for example, data of the coordinate positions of the start point and the end point of each road, and vector data connecting the start point and the end point. The map disk 16 also stores auxiliary data necessary for displaying the road map.

When the map data read from the map disk 16 is transferred to the memory 17, the system controller 13 performs a process of drawing a road map in a predetermined range in the map data. Then, the road map data that has been rendered into predetermined image data is supplied to the video processing unit 19, and as a video signal (for example, RGB signal) of a predetermined system for display, the video signal is used as the navigation device 10.
It is supplied to the display device 30 connected to the display device 30 and the road map is displayed on the display device 30.

The system controller 13 is connected with a key 18 which is an operation input section of the navigation device, and displays a road map based on a mode set by operating the key 18. For example, the map display range, display scale, display direction, etc. can be set by key input.

Further, the navigation device 10 of the present example includes
Even if the autonomous navigation unit 20 is connected and the GPS positioning signal from the artificial satellite cannot be received for some reason, positioning can be performed. That is, the autonomous navigation unit 20 is based on the outputs of the vehicle speed sensor 21, the angular speed sensor 22, and both sensors 21, 22 that count the vehicle speed pulses proportional to the speed of the vehicle output from the engine control computer of the vehicle. An autonomous navigation control unit 23 that measures the current position is provided to measure the current position. The positioning result is supplied to the system controller 13 of the navigation device 10.

Here, in this example, the autonomous navigation control unit 2
The output error of the angular velocity sensor 22 is corrected based on the control of No. 3. That is, the angular velocity sensor 22 has a characteristic that the zero-point voltage, which is the output voltage when the vehicle is in a stopped state, changes, and when the stop of the vehicle is detected, it is necessary to perform a correction process of the zero-point voltage. However, the conditions for performing the correction processing of the zero-point voltage are appropriately set so that accurate positioning can be performed by autonomous navigation. The specific processing will be described later.

Here, an example of a state in which the navigation device 10 of the present example is installed in an automobile will be described with reference to FIG. 2. As shown in FIG. 2, navigation is performed in a predetermined space such as a trunk of the automobile 50. The device 10 and the autonomous navigation unit 20 are fixed, and a display device 30 including a liquid crystal image display device or the like is arranged on the dashboard beside the steering wheel 51 in front of the driver's seat 52. The key 18 is attached to the side of the handle 51 here.
The vehicle speed sensor 21 of the autonomous navigation unit 20 is attached to an engine control computer (not shown) in the engine room.

Next, the correction processing of the zero-point voltage, which is necessary when the autonomous navigation unit 20 in the navigation apparatus of this example performs positioning by autonomous navigation, will be described .

[0024]

[0025]

FIG. 3 shows a vehicle equipped with a navigation device for carrying out the processing of this embodiment, which is mounted on a turntable 180
The relationship between the angular velocity ω _a detected by the angular velocity sensor 22 and the azimuth S _a detected by the autonomous navigation based on the output when the turn table starts rotating is shown. , When the angular velocity ω _a according to the rotation direction at that time begins to be detected and the turntable stops,
The angular velocity ω _a returns to 0. The azimuth S _a determined by the autonomous navigation control unit 23 based on the angular velocity ω _a coincides with the rotation angle of the turntable, and rotation of 180 ° is detected.

[0027]

[0028]

FIG. 4 compares changes in the zero-point voltage of the angular velocity sensor when the vehicle is running at an extremely low speed, when the processing of this example is executed and when the processing of this example is not executed .
The zero-point voltage V ₁ when the process of this example is executed is constant, but the zero-point voltage V ₂ when the process of this example is not executed is detected by greatly changing during the execution of the zero-point voltage correction process. The orientation will be greatly disturbed. Therefore, even when the direction of the own vehicle is greatly changed during ultra-low speed traveling such as when entering or leaving a garage, the autonomous navigation within the autonomous navigation unit 20 enables accurate positioning of the current position.

Next, a decision to perform a correction process of the zero point voltage of the angular velocity sensor, an example of a case where the a determination of the determination and the angular acceleration of the angular velocity will be described with reference to the flowchart of FIG. In this example, the rotation of the turntable or the like is determined based on the determination of the angular velocity and the determination of the angular acceleration. The autonomous navigation control unit 23 determines the traveling speed of the vehicle from the output of the speed sensor 21. When the traveling speed other than 0 km / h is determined (step 131), the turntable flag is cleared (step 132), and the process returns to the determination of the traveling speed. This turntable flag is a flag that is set using a memory or the like in the autonomous navigation control unit 23.

When it is determined in step 131 that the traveling speed is 0 km / h, the angular velocity determination process is performed based on the angular velocity detected by the angular velocity sensor 22 (step 1).
33). At this time, the angular acceleration is determined by a predetermined value β _{max turn} for determining the rotation of the turntable.
Judge whether it is over. As the value β _{max turn} of the angular acceleration at this time, for example, 1.0 deg / s ² is set. When it is determined in this determination that the angular acceleration exceeds the predetermined value β _{max turn} , the turntable flag is set (step 134), and the process returns to the determination of the traveling speed.

When it is determined in step 133 that the angular acceleration is equal to or less than the predetermined value β _{max turn} for determining the rotation of the turntable, the turntable flag is determined (step 135). Here, when it is determined that the turntable flag is set, it is determined whether the angular velocity exceeds a predetermined value ω _{max turn} for determining the rotation of the turntable (step 136). Value of angular velocity at this time
As ω _{max turn} , for example, 3.0 deg / s is set. If it is determined that the angular velocity exceeds the predetermined value ω _{max turn} , the process returns to the determination of the traveling speed. Also,
When it is determined that the angular velocity is less than or equal to the predetermined value ω _{max turn} , the turntable flag is lowered (step 137) and the process returns to the determination of the traveling speed.

When it is determined in step 135 that the turntable flag is not set, the correction processing of the zero point voltage of the angular velocity sensor output is started (step 13).
8). The process of correcting the zero-point voltage is as described above. Then, after the correction process is started, when the traveling speed is not 0 km (that is, when the traveling is started), the correction process is ended and the process returns to the speed judgment of step 131.

By performing the correction processing of the zero-point voltage based on the determination of the angular velocity and the determination of the angular acceleration in this way, it is possible to more accurately determine the rotation in the stopped state by the turntable or the like, and it is possible to more accurately determine the rotation. Positioning by highly autonomous navigation is possible.

Next, the determination of the correction processing of the zero point voltage of the angular velocity sensor is made by the determination of the angular velocity and the determination of the angular acceleration, and both the rotation at the turntable and the turning at the ultra low speed running are performed. an example in the case of performing measures will be described with reference to the flowchart of FIG. In this example, the judgment of the rotation in a stopped state by a turntable etc. is made from the judgment of the angular velocity and the judgment of the angular acceleration, and the judgment of the turning back at the ultra low speed running is made from the judgment of the angular acceleration.
First, the autonomous navigation control unit 23 determines the traveling speed of the own vehicle from the output of the speed sensor 21 (step 141), and the vehicle speed is 0 k / h.
When the traveling speed other than m is determined, the turntable flag is lowered (step 142), and the process returns to the determination of the traveling speed. This turntable flag is a flag that is set using a memory or the like in the autonomous navigation control unit 23.

When it is determined in step 141 that the traveling speed is 0 km / h, the angular velocity determination process is performed based on the angular velocity detected by the angular velocity sensor 22 (step 1
43). In the determination process of the angular acceleration at this time, it is determined whether or not the angular acceleration exceeds a predetermined value β _{max drift} for the countermeasure against ultra-low speed running. Value of angular acceleration at this time β
_{As maxdrift} , for example, 0.1 deg / s ² is set. When it is determined in this determination that the angular acceleration exceeds the predetermined value β _{max drift} , processing is performed to determine whether or not it exceeds a predetermined value β _{max turn} for determining the angular acceleration for determining the rotation of the turntable ( Step 144). As the value β _{max turn} of the angular acceleration for determining the rotation of the turntable, for example, 1.0 deg / s ² is set. When it is determined in this determination that the angular acceleration exceeds the predetermined value β _{max turn} , the turntable flag is set (step 145) and the process returns to the determination of the traveling speed. Also, step 1
If it is determined in 44 that the angular acceleration is equal to or less than the predetermined value β _{max turn} , the process returns to the determination of the traveling speed without setting the turntable flag.

When it is determined in step 143 that the angular acceleration is less than or equal to the predetermined value β _{max drift} for ultra-low speed traveling, the turntable flag is determined (step 146). Here, when it is determined that the turntable flag is set, it is determined whether the angular velocity exceeds a predetermined value ω _{max turn} for determining the rotation of the turntable (step 147). Value of angular velocity at this time ω
For example, 3.0 deg / s is set as the _{max turn} . If it is determined that the angular velocity exceeds the predetermined value ω _{max turn} , the process returns to the determination of the traveling speed. Also,
When it is determined that the angular velocity is equal to or less than the predetermined value ω _{max turn} , the turntable flag is lowered (step 148) and the process returns to the determination of the traveling speed.

When it is determined in step 146 that the turntable flag is not set, correction processing of the zero point voltage of the angular velocity sensor output is started (step 14).
9). The process of correcting the zero-point voltage is as described above. Then, after the correction process is started, when the traveling speed is not 0 km (that is, when the traveling is started), the correction process is ended and the process returns to the speed judgment of step 141.

In this way, from the determination of the angular velocity and the angular acceleration, the determination when the turntable or the like rotates in the stopped state and the determination of the direction change during the ultra-low speed running are performed, and the respective states are determined in the stopped state. If it is not determined, the correction of the zero-point voltage can be performed to more accurately determine the rotation of the turntable, etc. and the direction change during ultra-low speed traveling. Positioning by navigation becomes possible.

In the above-described embodiment, the navigation device is configured to perform both positioning by autonomous navigation and positioning by GPS. However, when positioning is performed only by autonomous navigation, each process described in the above embodiment is applied. it can.

Further, although in the above embodiments using angular velocity sensor, it may be used other sensors such as a geomagnetic sensor. Further, the values of the angular velocity and the angular acceleration at the time of determination shown in the above-mentioned embodiment also show an example, and the optimum values vary depending on the accuracy and structure of the sensor used.

Further, in the above-mentioned embodiment, the present invention is applied to the case where the navigation device mounted on the automobile measures the current position and displays the road map in the vicinity of the current position, but it is also applied to the navigation devices for other moving bodies. It is needless to say that the present invention can be applied to not only the case where the position is displayed on a map but also the case where the current position is simply measured.

[0043]

According to the present invention, when it is judged that the vehicle is moving based on the output of the angular velocity sensor together with the judgment that the vehicle is stopped by detecting the speed, and when it is judged from both judgments that the vehicle is stopped. Only by correcting the azimuth change, the sensor output fluctuation correction processing at the time of stop such as the fluctuation of the zero voltage is not performed when the vehicle rotates in a traveling stopped state like the rotation by the turntable. Will not be erroneously performed, and the direction can be correctly determined by the autonomous navigation even if the turntable rotates, for example.

In this case, when the angular acceleration detected from the output of the angular velocity sensor is within the fluctuation error of the angular velocity sensor,
By correcting the heading change, it becomes possible to correctly detect the heading change during ultra-low speed driving.For example, even if the vehicle is turned back at a slow speed to put the car in and out of the parking lot, autonomous navigation is possible. By this, the azimuth can be correctly measured.

Further, in the above-mentioned case, the predetermined azimuth change state is judged based on the angular velocity and the angular acceleration detected from the output of the angular velocity sensor, and when the predetermined azimuth change state is not detected, the azimuth change is corrected. By doing so, it becomes possible to more accurately determine the rotation by the turntable and the direction change at the time of ultra-low speed traveling, and the direction by the autonomous navigation can be more accurately measured.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an apparatus to which an embodiment of the present invention is applied.

FIG. 2 is a perspective view showing a state in which the device to which the embodiment is applied is attached to an automobile.

FIG. 3 is a characteristic diagram showing an example of azimuth change at the time of stop according to an embodiment.

FIG. 4 is a characteristic diagram showing an improved state of zero-point voltage change during ultra-low speed running.

FIG. 5 is a flowchart showing a correction process using an angular velocity and an angular acceleration according to an embodiment.

FIG. 6 is a flowchart showing another example of the correction process using the angular velocity and the angular acceleration according to the embodiment.

FIG. 7 is a characteristic diagram showing an example of changes in the zero-point voltage of the azimuth sensor.

FIG. 8 is a characteristic diagram showing a correction example of a zero-point voltage.

FIG. 9 is a flowchart showing an example of a conventional zero point voltage correction processing state.

FIG. 10 is a characteristic diagram showing an example of a conventional azimuth change when stopped.

[Explanation of symbols]

10 navigation device, 12 GPS signal processing unit,
13 system controller, 14 CD ROM control unit, 15 CD ROM driver, 16 map disk, 17 memory, 18 key, 19 image processing unit, 2
0 autonomous navigation unit, 21 vehicle speed sensor, 22 angular velocity sensor, 23 autonomous navigation control unit, 30 display device

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01C 19/00-19/72 G01C 21/00

Claims (4)

(57) [Claims] 1. A speed detecting means for detecting a traveling speed of a moving body based on an output of a speed sensor, an azimuth detecting means for detecting an azimuth of a moving body based on an output of an angular velocity sensor, the speed sensor and the angular velocity. Sensor output value and beforehand
A flag is stored based on the comparison means for comparing the set value with the comparison means.
A storage means which is, a positioning device including an angular velocity sensor zero point voltage correction means for performing a zero-point voltage correction of the output voltage of the upper Symbol angular velocity sensor, that has exceeded the predetermined speed by said speed detecting means
If it is detected, the flag stored in the storage means is lowered.
And, in a state of detecting a predetermined speed or lower the traveling speed of the moving object is set in advance by the speed detecting means, exceeds a first predetermined value the value of the angular acceleration that is detected from the output of the angular velocity sensor is set in advance If you set a flag, remember the above hands
Stored in a column, and detected below the predetermined speed by the speed detection means.
Angular acceleration detected from the output of the angular velocity sensor
If the degree value is less than or equal to the first predetermined value, the storage means stores a flag.
The above-mentioned angular velocity
The angular velocity value detected from the sensor output is
If the value is less than or equal to the predetermined value of 2, the flag is lowered and the above is stored.
Stored in the means, and detected below the predetermined speed by the speed detection means
Angular acceleration detected from the output of the angular velocity sensor
If the degree value is less than or equal to the first predetermined value, the storage means stores a flag.
A positioning device , wherein the angular velocity sensor zero point voltage correction means corrects the zero point voltage of the output voltage of the angular velocity sensor when a state in which the angular velocity sensor does not stand is stored . 2. The moving body is stopped at the predetermined speed.
The speed that can be regarded as
Angular acceleration set to determine the rotation on the table
The second predetermined value is the value on the turntable.
The positioning device according to claim 1, wherein the positioning device is an angular velocity value set for determining rotation . 3. A speed detecting means for detecting a traveling speed of the moving body based on an output of the speed sensor, an azimuth detecting means for detecting an azimuth of the moving body based on an output of the angular velocity sensor, the speed sensor and the angular velocity. Sensor output value and beforehand
Comparing means for comparing the set value, based on a result of comparison by the comparing means, flag storage means is stored, the upper Symbol angular velocity sensor zero-point voltage correction performing zero voltage correction of the output voltage of the angular velocity sensor A positioning device having means for detecting that the speed exceeds the predetermined speed by the speed detecting means.
If it is detected, the flag stored in the storage means is lowered.
And, in a state of detecting a predetermined speed or lower the traveling speed of the moving object is set in advance by the speed detecting means, exceeds a first predetermined value the value of the angular acceleration that is detected from the output of the angular velocity sensor is set in advance , The value of angular acceleration is preset
If a second predetermined value is exceeded, a flag is set and the above memory is stored.
Stored in the means, and detected below the predetermined speed by the speed detection means
Angular acceleration detected from the output of the angular velocity sensor
The degree value is less than or equal to the first predetermined value, and the storage means stores
With the flag being stored remembered,
The angular velocity value detected from the output of the
If the value is less than or equal to the third predetermined value, clear the flag
It is stored in the storage means, and the speed detection means detects the speed equal to or lower than the predetermined speed.
Angular acceleration detected from the output of the angular velocity sensor
The degree value is less than or equal to the first predetermined value, and the storage means stores
A positioning device , wherein the angular velocity sensor zero point voltage correction means corrects the zero point voltage of the output voltage of the angular velocity sensor when a state in which a flag is not set is stored . 4. The moving body is stopped at the predetermined speed.
The first predetermined value is the speed of the moving body.
It is the angular acceleration value set for measures against ultra-low speed running.
The second predetermined value determines the rotation on the turntable.
Is the angular acceleration value set for
Is set to determine the rotation on the turntable
The positioning device according to claim 3, wherein the positioning value is an angular velocity value .