JPH0792500B2 - Position detection device using GPS positioning system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle position detecting device for detecting the position of a vehicle traveling on an arbitrary road.

[0002]

2. Description of the Related Art Conventionally, as a method for detecting the position of a vehicle traveling in an arbitrary portion of a road traffic network, a process of performing necessary processing on output signals from a distance sensor, a direction sensor and both sensors. A dead reckoning navigation has been proposed in which a vehicle position data is obtained from a distance change amount ΔL caused by traveling of a vehicle and a vehicle direction θ by using a device. This method is
Based on L and θ, for example, the east-west component Δx of ΔL (=
ΔL × cos θ) and north-south direction component Δy (= ΔL × sin
θ) is calculated and the current position data (Px, Py) is calculated by adding the components Δx, Δy to the previous position data (Px ′, Py ′).

In the above-mentioned method, the position and direction data of the vehicle at the time of departure of the vehicle are required, the previous position data is required to calculate the subsequent position data, and the previous position data is required to calculate the subsequent position data. Position data is required. Since such a process is repeated, if an error is included in the detection signals of the distance sensor and the azimuth sensor, the error is accumulated and finally appears as a large error.

Therefore, it is desirable that the error contained in the distance sensor and the azimuth sensor be as small as possible, but the azimuth detected by the azimuth sensor is accompanied by an error due to the magnetization of the moving body if it is a geomagnetic sensor. If there is an error due to offset drift. Therefore, G
When a PS receiver is mounted and effective position data is obtained, the accumulated error is canceled by the information.

Here, the GPS (Global Positioning System) is a technique for positioning one's position by using radio waves from GPS satellites, and the principle thereof is a plurality of orbits that orbit a predetermined orbit. The purpose is to measure one's two-dimensional or three-dimensional position by measuring the propagation delay time of radio waves generated by an artificial satellite. in this case,
If the number of GPS satellites that can be simultaneously received is three, the two-dimensional position of the self is known, and if the number of GPS satellites is four, the three-dimensional position of the self is known.

However, the GPS currently launched
The number of satellites is limited, and a vehicle cannot always receive four satellites. Therefore, when positioning is performed by receiving radio waves from four satellites, vehicle position data including vehicle altitude data can be obtained, but when positioning is performed by receiving radio waves from three satellites, Vehicle altitude data will not be available. Therefore, the position is estimated by using the altitudes obtained when receiving radio waves from four satellites as they are.

[0007]

However, as the vehicle travels, the altitude of the vehicle fluctuates due to changes in the altitude of the road. Therefore, the position measurement is continued based on incorrect altitude data, and the position detection is performed. The accuracy decreases. Therefore, as a next best measure, as soon as the two-dimensional positioning mode is entered, G
Although it may be considered that the positioning data by PS is not adopted, it is desirable that the GPS data can be utilized in as many opportunities as possible.

The present invention has been made in view of the above-mentioned problems, and is made after three-dimensional positioning becomes impossible during traveling.
When two-dimensional positioning data that uses altitude data during three-dimensional positioning is adopted and the vehicle position obtained by dead reckoning or map matching navigation is corrected to a more accurate position,
It is an object of the present invention to provide a vehicle position detection device that can obtain a more accurate position and traveling locus even if there is a change in the altitude of the road.

[0009]

In order to solve the above-mentioned problems, a position detecting device using the GPS positioning system of the present invention has a current positioning mode of a three-dimensional positioning mode or a two-dimensional positioning mode. Based on the determination signal, the distance calculation means for starting the calculation of the travel distance based on the travel distance data of the vehicle when detecting the switching from the three-dimensional positioning mode to the two-dimensional positioning mode and the distance calculation means are constant. When the mileage is calculated, as long as it is determined that the vehicle is in the two-dimensional positioning mode, the data of the vehicle position detected by the subsequent two-dimensional positioning data is not adopted for correction. And means.

[0010]

[Operation] With the above configuration, the 3D positioning mode can
After switching to the three-dimensional positioning mode, the two-dimensional positioning data can be prevented from being adopted if the vehicle runs over a certain mileage. In general, the road gradient is distributed over a certain range, and there are very few roads with a certain gradient θm or more, and even if there is, it is considered to be a short distance. Therefore, assuming that the height difference of the vehicle in which the position detection error is allowable in the two-dimensional positioning mode is Hm, the adoption of the two-dimensional positioning data is stopped after traveling the distance Dm obtained by dividing the height difference Hm by the gradient θm. If so,
It is possible to eliminate the possibility of lowering the position detection accuracy due to the adoption of data with many errors. Of course, since the position detection is continued in the two-dimensional positioning mode until the vehicle travels the distance Dm, it is possible to utilize the GPS data.

[0011]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 2 shows a block diagram of a vehicle position detecting device for carrying out the present invention. The vehicle position detection device includes a wheel speed sensor 1 that detects the rotational speeds of the left and right wheels.
a, 1b, a gyro 2 for detecting a turning angular velocity (an optical fiber gyro that reads the turning angular velocity as a phase change of interference light, a vibration gyro that detects a turning angular velocity using a cantilever vibration technology of a piezo electric element, a mechanical gyro Data selected from the gyro 2 and the initial azimuth input from the geomagnetic sensor 3, which detects the absolute azimuth of the vehicle based on the geomagnetism, the GPS receiver 4, the geomagnetic sensor 3, etc. An azimuth estimating unit 5 for estimating the current azimuth of the vehicle based on the above, and an initial position (vehicle position set by the keyboard 10 or GPS receiver 4 based on the rotation speed pulse of the wheel detected by the wheel speed sensors 1a, 1b The travel distance data from the vehicle position input from) is calculated and is output from the bearing estimating unit 5. Position detection unit 6 which obtains position data and calculates a traveling locus starting from the initial position by dead reckoning, and the current positioning mode included in the output signal of GPS receiver 4 is the three-dimensional positioning mode or the two-dimensional positioning When it is detected that the three-dimensional positioning mode is switched to the two-dimensional positioning mode based on the determination signal indicating the mode, the calculation of the traveling distance is started based on the rotation speed pulse of the wheel speed sensors 1a and 1b. , The output of the GPS receiver 4 is cut off when the constant mileage Dm is calculated, and in the three-dimensional positioning mode, it is stored in the control unit 7, the navigation controller 8, and the map memory 11 that passes the output of the GPS receiver 4. It has a display 9 for displaying the vehicle position, azimuth, traveling locus, etc. on a CRT, a liquid crystal display or the like together with the road map.

The map memory 11 is a cassette tape or a CD.
-A storage medium such as a ROM, DAT, semiconductor memory, or IC memory is used, and a road network within a predetermined range as conventionally known,
Data such as intersections and railway transportation networks are stored in the form of combinations of nodes and links. The navigation controller 8 is composed of a graphic processor, an image processing memory and the like, and performs search of a map displayed on the display 9, input of an initial position, switching of scale, scrolling and the like.

A flow chart of the control procedure of the control unit 7 is shown in FIG. The control unit 7 receives a three-dimensional positioning / two-dimensional positioning determination signal output from the GPS receiver 4 at regular intervals (step (1)), and in the case of two-dimensional positioning, the rotation speeds of the wheel speed sensors 1a and 1b. Capture and count pulses (step (2)). The count value is n. Then, the count value n is compared with the number Nm corresponding to the distance Dm (for example, 2 km) (step (3)), and if n <Nm, GP
A signal for passing the position detection signal of the S receiver 4 (referred to as a connection signal) is output (step (7)), and the process returns. n
If ≧ Nm, a signal for separating the position detection signal of the GPS receiver 4 (referred to as separation signal) is output (step (4)
), The count value n is set to 0 (step (5)), and the process returns. If it is determined in step (1) that three-dimensional positioning is performed, a connection signal is output (step (6)) and the process returns.

The overall operation of the vehicle position detecting device having the structure shown in FIG. 2 will be described. First, the driver turns on the key to start the vehicle position detecting device before traveling, operates the keyboard 10 to select a road map within a predetermined range including the current position from the map memory 11, and displays it on the display 9. . Next, the keyboard 10 is operated to set the initial position of the vehicle. This setting is performed by moving the cursor indicating the position of the vehicle on the map. At this time, the initial direction of the vehicle is set by, for example, capturing the output of the geomagnetic sensor 3.
In this way, the data representing the initial position and the initial azimuth of the vehicle are supplied to the azimuth estimating unit 5 and the position detecting unit 6.

After the completion of the series of initial settings, the vehicle is started, and the position detecting section 6 calculates the traveling distance data from the initial position based on the wheel rotation speed signals of the wheel speed sensors 1a and 1b, and the azimuth estimating section. At 5, the present azimuth is integrated based on the angular velocity data of the gyro 2. Then, the position detection unit 6 calculates the traveling locus data based on the both data and supplies it to the navigation controller 8. The navigation controller 8 displays the vehicle position / direction and the traveling locus on the screen of the display 9 together with the road map.

Further, when vehicle position data is input from the GPS receiver 4 through the control of the control unit 7 during traveling, the vehicle position data is input again as the initial position of the vehicle. Therefore, the locus displayed on the display 9 is corrected to an accurate locus every time GPS data is received.

[0017]

As described above, according to the present invention, after the three-dimensional positioning becomes impossible, the two-dimensional positioning data is adopted by utilizing the altitude data at the time of the three-dimensional positioning, and the dead reckoning navigation and the map matching navigation are performed. In the case of correcting the vehicle position obtained by, for example, a more accurate position, the altitude data used during the three-dimensional positioning is adopted until the vehicle travels a certain distance Dm after the last three-dimensional positioning is performed and sufficient accuracy is achieved. Since the vehicle position can be measured with, it is possible to correct the vehicle position obtained by dead reckoning or map matching navigation to a more accurate position, and after traveling a certain distance Dm, the position detection data based on the two-dimensional positioning data is not adopted. Therefore, it is possible to eliminate the possibility that the correction is performed based on the positioning data with many errors. Therefore, a more accurate vehicle position and traveling locus can be obtained.

[Brief description of drawings]

FIG. 1 is a flowchart for explaining a method of adopting two-dimensional positioning data.

FIG. 2 is a block diagram of a vehicle position detection device.

[Explanation of symbols]

 1a, 1b Wheel speed sensor 2 Gyro 4 GPS receiver 5 Direction estimation unit 6 Position detection unit 7 Control unit

Claims (1)

[Claims] 1. A three-dimensional positioning is performed based on signals supplied from at least four GPS satellites, and altitude data of a vehicle is stored, which is previously stored when signals are supplied from three GPS satellites. 2 using the altitude data of the vehicle
Position of the vehicle that has a GPS receiver that performs dimensional positioning and that is obtained based on the mileage data and azimuth data of the vehicle detected by the mileage sensor and the azimuth sensor using the positioning data of this GPS receiver. In the position detection device that corrects the error, it is detected that the 3D positioning mode is switched to the 2D positioning mode based on the determination signal indicating whether the current positioning mode is the 3D positioning mode or the 2D positioning mode. In this case, as long as it is determined that the distance calculation means starts calculation of the travel distance based on the travel distance data of the vehicle and the constant travel distance is calculated by the distance calculation means, the two-dimensional positioning mode is determined, And a data selection unit that does not adopt the data of the position of the vehicle detected by the subsequent two-dimensional positioning data for correction. Position detecting apparatus using a PS positioning method.