JPH0758198B2 - Navigation device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a navigation device, and more particularly to a navigation device suitable for use in an automobile.

[Prior Art] In recent years, a navigation device for knowing a moving body, a position, and an operation route is being used.

Among them, particularly as a navigation device for automobiles, a combination of an acceleration sensor such as a geomagnetic direction sensor or a gas rate sensor and a distance sensor to know a relative position with respect to an initial setting position, a self-contained navigation route information system, or a loran Radio navigation assistance systems such as C have been developed.

However, in a self-contained navigation system such as a combination of a geomagnetic direction sensor and a distance sensor, or a gas rate sensor and a distance sensor, it is necessary to set the position at the start, and it is inevitable that errors will accumulate.

Especially, in terms of error accumulation, when calculating the travel route from a combination of an acceleration sensor such as a geomagnetic direction sensor and a tachometer, the error is 5%, that is, 50 km, 2.
There is an error of 5km.

On the other hand, the radio navigation Loran C is capable of knowing the absolute position, and is about 20 at sea, which is its original purpose.
The error is within 0m. However, in the case of land propagation, the propagation speed is different from that in the case of sea propagation, and if there are high mountains or buildings that cannot be ignored in the direction of arrival of the radio waves, the propagation distance will increase due to the diffraction of the radio waves. , The error increases to over 1000m. Even so, since the error between the radio wave propagation velocities at sea and land is a constant value, it is possible to obtain a Loran chart considering land propagation by calculation. Therefore, although the problem due to the difference in propagation speed is solved, the influence of high mountains and buildings remains and the error is several hundred meters. In addition, it may not be possible to receive in a tunnel, underground, etc., and it becomes impossible to know the absolute position.

By the way, GPS (Grobal Positioning
System) NAVSTAR, such as NAVSTAR with an absolute error of 100 m or less (when using C / A code (15 m or less when using P code)) is being developed by the US Department of Defense. However, despite the need for 18 satellites to be used 24 hours a day, only 7 satellites are currently available, and there is only 1 to 3 hours of usable time per day. .

In the taxi industry, AVM (Automatic Vehicle Monit)
oring System) -automatic display system of vehicle position etc.-is quite popular. Since the representative method of AVM is a distributed transmission method, it is necessary to install sign post radio stations finely, and the position accuracy is 500m to 1000m or more.

[Problems to be solved] In the conventional navigation device described above, the error accumulation is large in the self-contained navigation such as the combination of the geomagnetic direction sensor and the distance sensor, and in the radio navigation, the error may be set depending on the region.
In the worst case, it may not be possible to measure the absolute position, and satellite navigation such as GPS NAVSTAR cannot always be used 24 hours a day. There was a problem in that it was necessary to install unmanned lines and receiving stations on the streets in detail.

The present invention has been made in consideration of the above problems.
The objective is to provide a navigation device that can be used 24 hours a day, and has a measurement accuracy within 200 m anywhere in Japan.

[Means for Solving the Problems] In order to achieve the above object, the navigation device of the present invention integrates the output of the acceleration sensor to travel the travel route information detecting device, and the current for measuring the absolute position by radio navigation. The outputs from the navigation absolute position detection means and the travel route information detection means are integrated to output a reset signal every time the vehicle travels a certain distance, and when the control signal is received from the abnormal reception detection means described later, the output of the reset signal is stopped. By detecting abnormal reception of radio waves based on the signal from the traveling distance monitor and the radio navigation absolute position detection means, it is determined that it is not possible to measure the absolute position by radio navigation, and the position data The position data from the synthesis circuit and the position data in the anomaly propagation database are compared to determine whether the area is an anomalous propagation area, and Abnormal reception detection means for outputting a control signal when it is determined to be in the reception or abnormal propagation area, and when measuring the current position from the travel route information detection means and inputting a reset signal from the travel distance monitor When the control signal is input from the position data synthesizing unit that corrects the current position at constant distances based on the detection result of the radio navigation absolute position detecting unit, and the radio navigation absolute position detecting unit when the control signal is input from the abnormal reception detecting unit. From the position data synthesizing means to prohibit correction of the current position by radio navigation.

That is, the current position is provided with a traveling route information detecting unit that integrates the output of the acceleration sensor mounted on the moving body to calculate a traveling route from the starting point, and a radio navigation absolute position detecting unit that measures the absolute position of the moving body. After manually initializing, or after correcting the position data calculated by the traveling route information detecting means by the radio navigation absolute position detecting means, a certain distance travels only by the traveling route information detecting means to detect the current position, When accumulated error cannot be ignored (for example, 10
When the cumulative error reaches 500 m after traveling for km), the calibration is performed by the radio navigation absolute position detection means. At this time, the radio navigation is based on the current position data output from the position data synthesis means and the reception state. It is possible to obtain comprehensive high-accuracy position information data by detecting the case where the calibration by means of is impossible and in that case prohibiting the correction by the radio navigation absolute position detecting means.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a vehicle-mounted navigation device according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a travel route information subsystem that integrates the output of the acceleration sensor to calculate a travel route from a starting point. Specifically, a combination of a geomagnetic direction sensor and a distance sensor, a gas rate sensor, a laser gyro, or the like is used, and acceleration is integrated to calculate a velocity vector V from the initial point. Reference numeral 2 denotes a radio navigation assistance subsystem that measures the absolute position of the moving body, and receives radio waves for radio navigation such as Loran C to calculate the absolute position.

3 is a mileage monitor, 4 is a position data synthesizing circuit,
The traveling distance monitor 3 integrates the output of the traveling route information subsystem, and sends a reset signal to the position data synthesizing circuit 4 every fixed distance traveling.

Further, 5 is a control circuit, 6 is an abnormal reception monitor, and 7 is an abnormal propagation database. The abnormal reception monitor 6 is used when the reception is impossible in the underground or in a tunnel, or when it is determined that the abnormal propagation occurs due to the diffraction phenomenon of radio waves due to high mountains or buildings, and the control circuit 5 and the traveling distance monitor 3 Send a control signal to. Then, the control circuit 5 stops the Loran output from the radio navigation assistance subsystem, and the mileage monitor 3 stops sending the reset signal. At this time, whether reception is possible or not is judged by the reception monitor signal from the radio navigation assistance subsystem, and if it is the abnormal propagation area, the position data output of the position data synthesizing circuit 4 and the position data of the abnormal propagation database 7 are judged. Compare with and check if they match and judge.

In the above configuration, the position data synthesizing circuit 4 detects the current position from the velocity vector of the travel route information subsystem 1 and the absolute position data of the radio navigation assistance subsystem 2. That is, when the position data synthesizing circuit 4 receives the reset signal of the traveling distance monitor 3 at time t ₀ , the position data synthesizing circuit 4 initializes the position data which is its own output. At this time, the initial value P
₀ to (t ₀₎ Using Loran output of the control circuit 5 L (t _0). Then, after the initialization, the velocity vector V from the travel route information subsystem 1 is integrated and sequentially added to the initial value P ₀ , and the position data at time t can be set. To get

FIG. 2 is a block diagram of a vehicle-mounted navigation device according to another embodiment of the present invention.

The navigation device shown in FIG. 1 has the position data synthesizing circuit 4 shown in FIG. 1 developed to show the position and travel route of the vehicle on a display together with a map.

In FIG. 2, 8 is a microcomputer and 9 is a CDRO.
A map database in which map information is stored in M or FDD (floppy disk), 10 is a display such as a CRT display, and 11 is a position data synthesizer.

In the above configuration, the microcomputer 8 superimposes the position data of the position data synthesizer 11 on the map data of the map database 9 and displays it as a map with the traveling route of the display 10. As a result, the driver can significantly reduce the driving load.

Further, if the obtained position data is sent to the center by using an in-vehicle wireless transmission / reception device and is utilized for vehicle management in the center, it is possible to perform highly accurate vehicle management which has never been achieved.

[Effects of the Invention] As described above, the present invention combines the advantages of self-contained navigation and radio wave navigation, thereby making it possible to propagate radio waves abnormally anywhere in the world, for example, in tunnels or underground where radio waves do not reach. Even in the region, there is an effect that it is possible to provide a navigation device that can know the vehicle position within an error of approximately 200 to 300 m.

In addition, there is an effect that it can be used anywhere in the world and a totally stable system can be used at a very low cost.

[Brief description of drawings]

FIG. 1 is a block diagram of a vehicle-mounted navigation device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a vehicle-mounted navigation device according to another embodiment of the present invention. 1: Travel route information subsystem 2: Radio navigation assistance subsystem 3: Travel distance monitor 4: Position data synthesis circuit 5: Control circuit 6: Abnormality reception monitor 7: Abnormality propagation database 8: Microprocessor 9: Map database 10: Display Device 11: Position data synthesizer

Claims (2)

[Claims] Claim: What is claimed is: 1. A travel route information detecting means for integrating the output of an acceleration sensor to detect a travel route, a radio navigation absolute position detecting means for measuring an absolute position by radio navigation, and an output from the travel route information detecting means. A mileage monitor that integrates and outputs a reset signal every time the vehicle travels a fixed distance, and stops the output of the reset signal when a control signal is received from the abnormal reception detection means described later, and a signal from the radio navigation absolute position detection means. By detecting abnormal reception of radio waves based on the above, it is determined that it is impossible to measure the absolute position by radio navigation, and the position data from the above position data synthesis circuit is compared with the position data in the anomaly propagation database. Determine whether the area is an abnormal propagation area, and output a control signal when it is determined that an abnormal reception or an abnormal propagation area is present. Abnormal reception detection means and the current position is measured from the travel route information detection means, and at a constant distance based on the detection result of the radio navigation absolute position detection means when a reset signal is input from the travel distance monitor. When a control signal is input from the position data synthesizing unit that corrects the current position and the abnormal reception detecting unit,
And a control means for stopping the output from the radio navigation absolute position detecting means to the position data synthesizing means to prohibit the correction of the current position by radio navigation. 2. The position data synthesizing means synthesizes a current position on a map from a map database, a display for displaying a map based on the data of the map database, the current position and the data of the map database. The navigation device according to claim 1, further comprising a microprocessor for displaying on the display.