JPH0942979A - On-vehicle navigation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle navigation device with self-contained navigation capable of accurately detecting and displaying the position of an own vehicle even when running on a sharp slope such as a ridge path. SOLUTION: For an azimuth sensor, a three-axis acceleration sensor 3 and a gyro sensor 4 are used, and they are combined with a speed sensor 5 to compute output data for all of them and find a speed and an angle speed on a horizontal axis. There is no possibility of errors due to the attitude of a vehicle and the inclination of a slope, so that the position of an own vehicle can be recognized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-mounted navigation device, and more particularly, to independently (estimate) the position of a vehicle on the map.
The present invention relates to a navigation device that detects by navigation.

[0002]

2. Description of the Related Art An in-vehicle navigation system reads out map data corresponding to the current position of an automobile from a map data storage section such as a CD-ROM, draws a map on the display screen based on the map data, and The current position of the vehicle is fixedly displayed as a vehicle position mark (location cursor) at a certain position on the display screen (for example, the center position of the display screen), and the map is scrolled according to the movement of the vehicle.

Various means have been put into practical use as means for detecting the current position of an automobile, which is indispensable in such a vehicle-mounted navigation device. Broadly speaking, they are roughly classified into autonomous (guess) navigation using a distance sensor and an angle sensor. And satellite navigation using a GPS (Grobal Positioning System) receiver that receives radio waves from satellites.

In the self-contained navigation, a vehicle speed sensor and a gyro sensor are provided on the vehicle to detect the traveling distance and direction of the vehicle and obtain the vehicle position on the map. The vehicle speed sensor is mainly a pulse sensor that detects the number of revolutions of a wheel or the like within a unit time, and measures and outputs the moving distance. The gyro sensor includes a mechanical gyro, a gas rate gyro, and an optical fiber gyro, which all detect and output the turning angle of the vehicle.

The output data of these detecting means are input to a navigation controller having a microcomputer, the position calculating section calculates the vehicle position and direction, and the display section displays the current position of the vehicle.

[0006]

In a vehicle-mounted navigation device equipped with such a vehicle speed sensor and a gyro sensor, when the vehicle travels on a slope, especially on a steep slope, the vehicle speed sensor uses the number of rotations of the wheels of the vehicle. Therefore, the error becomes larger than the horizontal distance. Further, since the vehicle is tilted, the sensitivity of the gyro sensor decreases with respect to the horizontal axis. For example, as shown in the explanatory view of FIG. 3, assuming that the output of the gyro sensor provided in the vehicle 10 traveling in the uphill direction is ω, the angular velocity ω ′ with respect to the horizontal axis is ω ′.
Therefore, on a steep slope such as a mountain pass, when the vehicle position is displayed on the map, the vehicle position may be displayed off the road, and accurate navigation is not possible. There is a problem that it is not done. The present invention provides a vehicle-mounted navigation device that solves such a problem.

[0007]

According to the present invention, the above-mentioned problem is solved by calculating the present vehicle position from the output data from the map data storage means storing map data, the distance sensor and the direction sensor provided in the vehicle. In a vehicle-mounted navigation device equipped with a vehicle position calculation means and a map image drawing means for drawing a map image of a vehicle surroundings detected by the vehicle position calculation means together with a vehicle position mark using map data and displaying the screen on a display means, The azimuth sensor is composed of a triaxial acceleration sensor and a gyro sensor, and the vehicle position calculating means detects the vehicle speed based on the acceleration in each axial direction detected by the triaxial acceleration sensor and the vehicle acceleration detected by the distance sensor. The first step of calculating the tilt angle, the vehicle speed detected by the distance sensor, and the calculated tilt angle The second step of calculating the vehicle speed in the direction, and the third step of calculating the horizontal angular speed by the angular speed of the vehicle detected by the gyro sensor and the calculated tilt angle are included. It is solved by calculating the current vehicle position using the result.

[0008]

[Function] The three-axis sensor provided as the acceleration sensor is
Since the vehicle acceleration in each x, y, z direction is detected and output,
By using these output data and the acceleration data of the vehicle obtained from the vehicle speed sensor, the vehicle position calculation means can calculate the inclination angle when the vehicle travels while inclining, that is, the inclination angle of the road. When the inclination angle is obtained, the vehicle position calculation means converts the vehicle speed data of the vehicle speed sensor into horizontal vehicle speed data, and the angular velocity data of the gyro sensor into horizontal angular velocity data. Using both data, the vehicle position calculation means can obtain the own vehicle position on the accurate horizontal axis and display it on the map screen even when the vehicle travels on the slope.

[0009]

1 is a schematic block diagram of a vehicle-mounted navigator device according to the present invention. In FIG. 1, reference numeral 1 is a CD-ROM (map data storage unit) that constitutes a road map. The map data is composed of (1) road layer, (2) background layer for displaying objects on the map, (3) character layer for displaying municipalities, and the like.

A CRT display device 2 inputs a video signal and displays a map on a screen together with a vehicle position mark, an intersection guidance image and the like. Reference numeral 3 is a three-axis acceleration sensor that detects the traveling direction of the vehicle, 4 is a gyro sensor that also detects the traveling direction of the vehicle, and 5 is a vehicle speed sensor that detects the traveling distance.

6 is a map search key, a map scroll key,
The operation unit includes a route search mode key, a set key, a search start key, and the like.

Reference numeral 7 denotes a navigation controller having a microcomputer configuration, which has various navigation functions.
7A shows the acceleration sensor 3, the gyro sensor 4, and the gyro sensor 4 in the navigation mode.
A vehicle position calculation unit that calculates the current position (longitude, latitude) of the vehicle based on each data detected by the vehicle speed sensor 5,
7B is a CD-ROM based on the calculated vehicle position data
A map image around the vehicle position is drawn together with the vehicle position mark using the map data of No. 1, and the CRT display device 2
It is a map image drawing unit that is displayed on the screen.

FIG. 2 is an explanatory view of the operation of the vehicle-mounted navigator device of the present invention. In the device of the present invention, the traveling posture of the vehicle is determined by using a three-axis acceleration sensor and a gyro sensor together for the direction sensor. Then, the velocity and the angular velocity with respect to the horizontal axis are calculated. Regarding the triaxial acceleration sensor, for example, Japanese Patent Application Laid-Open No. 3-27604.
The device disclosed in Japanese Patent No. 2 can be used.

In FIG. 2, θ is the inclination angle of the traveling slope, and the vehicle 1 is assumed to travel in the climbing direction on this slope. When the vehicle acceleration is a (m / sec), the outputs of the triaxial acceleration sensor 3 are as follows. Where g is the acceleration of gravity, a _x, a _{y, and} a _z are the x axis,
It is the output of the acceleration sensor 3 in the y-axis and z-axis directions.

[Equation 1]

Of these, the vehicle acceleration a is the vehicle speed sensor 5
Therefore, the slope angle θ of the slope can be calculated from this mathematical expression.

Therefore, the horizontal velocity v'is as follows.

[Equation 2]

On the other hand, the output of the gyro sensor 4 is ω (° / s
ec), if the angular velocity with respect to the horizontal axis is ω ', this ω'is as follows.

(Equation 3)

In this way, the velocity v'and the angular velocity ω'converted in the horizontal direction are calculated, and the vehicle position calculation unit 7A calculates the vehicle current position with respect to the horizontal axis using these results, and the map image The drawing unit 7B draws a map image around the vehicle position together with the vehicle position mark using the map data of the CD-ROM 1 based on the calculated vehicle position data, and displays it on the CRT display device 2 on the screen.

The above is the case where the vehicle travels on the uphill or the like while tilting in the front-rear direction. Therefore, the correction value for the x-axis component is calculated. The components also need to be corrected.
Also in this case, the device of the present invention can obtain the velocity and the angular velocity with respect to the horizontal axis by the same idea as described above.

[0020]

As described above, according to the present invention, in a vehicle-mounted navigation device equipped with a vehicle position detecting means for self-contained navigation, a azimuth detecting sensor is used in combination with a three-axis acceleration sensor and a gyro sensor. By combining the sensor and the output data of both to calculate the velocity and angular velocity on the horizontal axis, errors such as the posture of the vehicle and the slope of the slope can be eliminated, and the accurate position of the vehicle can be known. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the operation of the device of the present invention.

FIG. 3 is an explanatory diagram of an operation of a conventional device.

[Explanation of symbols]

 1 CD-ROM (map data storage unit) 2 display device 3 3-axis acceleration sensor 4 gyro sensor 5 vehicle speed sensor 6 operation unit 7 navigation controller 7A vehicle position calculation unit 7B map image drawing unit 10 vehicle

Claims (1)

[Claims] 1. A map data storage means for storing map data, a vehicle position calculation means for calculating a vehicle current position based on output data from a distance sensor and a direction sensor provided in the vehicle, and a vehicle position calculation means for detecting the current vehicle position. In a vehicle-mounted navigation device equipped with a map image drawing means for drawing a map image of the vicinity of a vehicle using map data together with a vehicle position mark and displaying it on a screen of a display means, the orientation sensor comprises a triaxial acceleration sensor and a gyro sensor. The vehicle position calculation means calculates a tilt angle of the vehicle based on accelerations in respective axial directions detected by the three-axis acceleration sensor and accelerations of the vehicle detected by the distance sensor, and the distance sensor. A vehicle speed in the horizontal direction based on the vehicle speed detected by the vehicle and the tilt angle calculated above.
And a third step of calculating the angular velocity in the horizontal direction based on the angular velocity of the vehicle detected by the gyro sensor and the calculated tilt angle, and calculating the current vehicle position using the calculation results of the steps. An in-vehicle navigation device characterized by: