JPH08313281A - Navigation device - Google Patents

Abstract

PURPOSE: To remove cumulated errors when a position is measured by a self-contained navigation method, by providing a position-correcting means for correcting a relative position obtained by a positioning means to a predetermined point. CONSTITUTION: A moving distance-detecting part 1 counts a count of speed pulses obtained from a vehicle, integrates the count of speed pulses by a running distance coefficient thereby to obtain a moving distance from a previous position. Simultaneously with this, a moving azimuth-detecting part 12 integrates a shift angle by a bearing calculation coefficient thereby to obtain a moving bearing from the previous position. A position-determining part 13 obtains a relative position from the previous position on the basis of the moving distance sent from the detecting part 11 and the moving bearing from the detecting part 12. Based on the change of a state when a position of a GPS is detected by a GPS-checking part 14, a position-correcting part 15 corrects the relative position of the vehicle obtained by the position-determining part 13 to a predetermined point. In this manner, cumulated errors are removed and a positioning accuracy is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a navigation device mounted on a moving body such as a vehicle.

[0002]

2. Description of the Related Art A conventional navigation device will be described below with reference to the drawings.

FIG. 5 is a block diagram showing a configuration of a conventional navigation device, which is provided with a positioning means called autonomous navigation. In FIG. 5, reference numeral 1 is a moving distance detecting unit that obtains a moving distance based on the number of vehicle speed pulses and a traveling distance coefficient, 2 is a moving azimuth detecting unit that obtains a moving azimuth based on a displacement angle and an azimuth calculation coefficient, and 3 is a moving body. This is a position determination unit that calculates the current position by performing cumulative calculation from the initial position based on the moving distance obtained from the distance detection unit 1 and the moving direction obtained from the moving direction detection unit 2.

FIG. 6 is a diagram showing a movement locus of a conventional navigation device, showing an actual movement locus and a movement locus obtained by autonomous navigation.

As shown in FIGS. 6 and 7, the moving distance detecting unit 1 detects a vehicle speed pulse signal obtained from the vehicle, and adds a predetermined running distance coefficient to the obtained vehicle speed pulse number to obtain the moving distance. At the same time, the moving azimuth detecting unit 2 calculates the moving azimuth by integrating the azimuth calculation coefficient with the displacement angle. When the position determination unit 3 obtains the movement distance and the movement direction from the movement distance detection unit 1 and the movement direction detection unit 2, respectively, the position determination unit 3 adds the movement distance and the movement direction to the previous positioning point to obtain the current position.

FIG. 7 is a block diagram showing the configuration of a conventional navigation device.
ystem) is provided with a positioning means. In FIG. 7, 4 is a GPS positioning unit that receives positioning data from GPS satellites, and 5 is a GPS positioning unit 4
It is a position determination unit that obtains the current position from the positioning data obtained from.

FIG. 8 is a diagram showing a movement locus of a conventional navigation device, and shows an actual movement locus and a movement locus obtained by GPS.

As shown in FIGS. 7 and 8, the GPS positioning section 4 receives radio waves from a plurality of GPS satellites to obtain positioning data. This positioning data includes absolute position information, error range information, accuracy information and the like. GPS positioning unit 4
If the positioning accuracy is good based on the accuracy information obtained by, the positioning position included in the positioning data is set as the current position, but if the positioning accuracy is poor or the reception is impossible, the current position cannot be obtained.

A positioning position obtained by autonomous navigation is called a relative position, and a position obtained by GPS is called an absolute position.

[0010]

However, in the above-mentioned conventional configuration, in the positioning means called autonomous navigation, for example, the vehicle speed pulse signal contains a slight error due to various condition changes such as tire wear and air pressure change. ,
Since even a slight error is accumulated from the initial position, as shown in FIG. 6, a slight error is accumulated and increased as the moving distance becomes long, and cannot be ignored. It had a problem that it became.

On the other hand, since the positioning means called GPS receives radio waves from a plurality of GPS satellites, positioning is performed depending on the arrangement of the captured GPS satellites and the presence of obstacles such as tunnels, as shown in FIG. There were problems that the accuracy was poor and that there was an unreceivable section.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a navigation device with good positioning accuracy by eliminating the cumulative error by correcting the relative position obtained by autonomous navigation.

[0013]

In order to achieve this object, the present invention is a navigation device for displaying the calculated position of a moving body on map data, and detecting a moving distance from a previous position. Means, a moving direction detecting means for obtaining a moving direction from the previous position, and a position determining means for obtaining a relative position from the previous position based on the moving distance obtained from the moving distance detecting means and the moving direction obtained from the moving direction detecting means. And a GPS check means for determining a change in the GPS satellite acquisition status, and a position correction means for correcting the relative position obtained by the position determination means to a predetermined point based on the change in the GPS satellite acquisition status by the GPS check means. It was configured with.

Further, when the GPS checking means finds that the state in which at least one GPS satellite having a high elevation angle is captured is changed to the state in which only the GPS satellite having a low elevation angle is captured, the position correcting means shields the moving body. It is determined that the object is located at the entry point of the object, and the relative position obtained by the position determining means is corrected to the entry point of the shield.

In addition, the GPS check means is configured to detect at least one low-elevation-angle GPS from the situation that the GPS satellite cannot be captured.
When it is determined that the satellite has been captured, the position correction means determines that the moving body is near the exit of the shield, and corrects the relative position obtained by the position determination means to near the exit of the shield. .

Further, when the GPS checking means obtains a change from the situation in which the captured GPS satellites are only low elevation angle satellites to the situation in which at least one high elevation angle GPS satellite is captured, the position correcting means moves. It is determined that the body has escaped from the shield, and the relative position obtained by the position determining means is corrected to the escape point of the shield.

[0017]

With this configuration, the relative position can be corrected to a predetermined point on the basis of the change in the acquisition status of the GPS satellites, and the cumulative error in the positioning by the autonomous navigation can be removed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The present embodiment shows a navigation device capable of correcting the relative position of a moving body obtained by autonomous navigation and removing the accumulated error.

FIG. 1 is a block diagram showing the configuration of a navigation device according to an embodiment of the present invention. Such a navigation device is often used for mounting on a vehicle, and will be mounted in a vehicle in the following description. As described below.

In FIG. 1, reference numeral 11 denotes a moving distance detecting unit for obtaining a moving distance based on the number of vehicle speed pulses and the traveling distance coefficient.
2 is a moving azimuth detecting unit that obtains a moving azimuth based on the displacement angle and azimuth calculation coefficient, and 13 is a relative from the previous position based on the moving distance from the moving distance detecting unit 11 and the moving azimuth from the moving azimuth detecting unit 12. A position determination unit for obtaining the position, 14 is a GPS check unit for checking the acquisition condition of the GPS satellites, and 15 is a relative position determined by the position determination unit 13 based on the change in the acquisition condition of the GPS satellites obtained from the GPS check unit 14. The position correction unit corrects the position to a predetermined point on the road.

The moving distance detecting section 11 is not limited to the vehicle speed pulse, and the moving distance may be obtained by an acceleration sensor or the like.

Further, the configuration shown in FIG. 1 shows only the positioning means of the navigation device in this embodiment, but the vehicle position obtained by the position correction section 15 is LCD (Liquid) together with map data having road information and the like. Cryst
al Display) is displayed on the display, etc. and is notified to the user.

The operation of the navigation device constructed as above will be described below.

As shown in FIG. 1, the moving distance detecting unit 11 counts the number of vehicle speed pulses obtained from the vehicle, and adds the running distance coefficient to the number of vehicle speed pulses to obtain the moving distance from the previous position. At the same time, the moving azimuth detecting unit 12 adds the azimuth calculation coefficient to the displacement angle to obtain the moving azimuth from the previous position. The position determination unit 13 obtains the relative position from the previous position based on the movement distance from the movement distance detection unit 11 and the movement direction from the movement direction detection unit 12.

In the configuration shown in FIG. 1, the GPS positioning means is not shown, but the GPS check section 14 captures the GPS satellites based on the positioning data from the GPS positioning section shown in the conventional example. Is a means of understanding
It goes without saying that the navigation device of this embodiment may perform GPS positioning.

In GPS positioning, positioning cannot be performed unless at least three or more GPS satellites are captured. However, when the vehicle moves in a tunnel or under an overpass, there is a shield. Is difficult to receive the radio wave from the GPS satellite, and the capturing status of the GPS satellite changes. The manner of correcting the relative position obtained by the autonomous navigation based on the change in the GPS satellite acquisition state will be described below.

FIG. 2, FIG. 3 and FIG. 4 are conceptual views of a navigation device in one embodiment of the present invention, and in these drawings, a tunnel is shown as an example of a shield.

The GPS check unit 14 checks the change in the acquisition status of the GPS satellites. In the present embodiment, if the elevation angle of the acquired GPS satellites is 30 ° or less, the GPS satellite has a low elevation angle. If it is larger than 30 °, it is decided to be a GPS satellite with a high elevation angle.

FIG. 2 shows how a vehicle rushes into a tunnel. As shown in FIG. 2, assuming that the previous position was point A and the relative position obtained this time by the position determination unit 13 was point B, the GPS check unit 14 determines that at least one GPS satellite with a high elevation angle is present at point A. However, in the case where only GPS satellites with a low elevation angle are captured at point B, the position correction unit 15 is trying to move the vehicle from a position where there is no obstacle to a position where there is an obstacle. Then, the point B is corrected to the point C, which is the entry point into the nearby tunnel or underpass, which is considered to be the cause of the shielding.

FIG. 3 shows how the vehicle approaches from the inside of the tunnel to the vicinity of the exit of the tunnel. As shown in FIG. 3, the previous position is the point D in the tunnel, and the relative position obtained by the position determining unit 13 this time is E.
If the GPS check unit 14 cannot capture any GPS satellites at the point D, but the GPS check unit 14 can capture at least one GPS satellite with a low elevation angle at the point E, the position correction unit 15 determines It is determined that the vehicle is about to move from the position where the obstacle exists to the vicinity of the exit of the obstacle, and point E is corrected to point F, which is the exit of the tunnel or underpass, which is considered to be the cause of the obstacle.

FIG. 4 shows how the vehicle escapes from the tunnel. As shown in FIG. 4, assuming that the previous position was the G point and the relative position obtained by the position determining unit 13 this time was the H point, the GPS check unit 14 captures only the GPS satellite with a low elevation angle at the G point. However, at the point H, if at least one GPS satellite with a high elevation angle is captured, the position determination unit 13 determines that the vehicle has escaped from the position where the obstacle exists to the position where the obstacle does not exist. Judgment is made, and point H is corrected to point I, which is an escape point under tunnels or underpasses, which is considered to be the cause of shielding.

As described above, in the present embodiment, the position correcting unit 15 corrects the relative position of the vehicle determined by the position determining unit 13 to a predetermined point based on the change in the GPS satellite acquisition status from the GPS checking unit 14. By doing so, it is possible to remove accumulated errors and perform accurate positioning.

[0033]

As described above, according to the present invention, the acquisition status of GPS satellites is checked, the relative position obtained by autonomous navigation is corrected based on this acquisition status, and the cumulative error in positioning by autonomous navigation is removed. Therefore, a navigation device with high positioning accuracy can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a navigation device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a navigation device according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram of a navigation device according to an embodiment of the present invention.

FIG. 4 is a conceptual diagram of a navigation device according to an embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a conventional navigation device.

FIG. 6 is a diagram showing a movement path of conventional navigation.

FIG. 7 is a block diagram showing a configuration of a conventional navigation device.

FIG. 8 is a diagram showing a movement trajectory of a conventional navigation device.

[Explanation of symbols]

 Reference Signs List 11 moving distance detecting unit (moving distance detecting unit) 12 moving direction detecting unit (moving direction detecting unit) 13 position determining unit (position determining unit) 14 GPS check unit (GPS checking unit) 15 position correcting unit (position correcting unit)

Claims (4)

[Claims] 1. A navigation device for displaying the calculated position of a moving body on map data, comprising moving distance detecting means for obtaining a moving distance from a previous position, and moving azimuth detecting means for obtaining a moving azimuth from the previous position. And a position determining means for obtaining a relative position from a previous position based on the moving distance obtained from the moving distance detecting means and the moving direction obtained from the moving direction detecting means, and a GP for judging a change in the capturing condition of the GPS satellite.
GP by S check means and GPS check means
A navigation device, comprising: a position correction unit that corrects the relative position obtained by the position determination unit to a predetermined point based on a change in the capture state of the S satellite. 2. The position correcting means moves when the GPS checking means obtains a change from a situation in which at least one GPS satellite with a high elevation angle is captured to a situation in which only a GPS satellite with a low elevation angle is captured. 2. The navigation device according to claim 1, wherein the body is determined to be a rush point into the shield, and the relative position obtained by the position determining means is corrected to the rush point of the shield. 3. A GPS with at least one low elevation angle when the GPS satellite cannot be captured from the GPS check means.
When it is found that the situation in which the satellite is captured is changed, the position correction means determines that the moving body is near the exit of the shield, and corrects the relative position obtained by the position determining means to near the exit of the shield. The navigation apparatus according to claim 1, wherein the navigation apparatus is a navigation apparatus. 4. The position correction means is obtained when the GPS check means obtains a change from a situation in which the captured GPS satellites are only low elevation angle satellites to a situation in which at least one high elevation angle GPS satellite is captured. The navigation device according to claim 1, wherein the vehicle determines that the moving body has escaped from the shield, and corrects the relative position obtained by the position determining means to the escape point of the shield.