JP2871103B2 - Car navigation system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle navigation device.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing an example of a conventional car navigation system. In FIG. 3, 1 is a traveling distance sensor, 2 is a rate gyro which is a direction sensor, 3
Is a calculating means for calculating the current position of the vehicle and the like. The traveling distance sensor 1 and the rate gyro 2 are connected to the calculating means 3. Reference numeral 4 denotes auxiliary storage means for storing map data and the like, and reference numeral 5 denotes control means. The control means 5 is connected to arithmetic means 3 and auxiliary storage means 4. 6 is control means 5
Is a display means such as a CRT connected to the.

Next, the operation of the above conventional example will be described with reference to FIG. In the above conventional example, when the vehicle travels (step (hereinafter referred to as ST) 1), the position calculation means 33 calculates the current position of the vehicle according to the outputs of the travel distance sensor 1 and the rate gyro 2 (ST2). The control means 5 displays the current position data of the vehicle from the arithmetic means 3 and the map data from the auxiliary storage means 4 on the display means 6 to inform the driver of the current position and the like.

Here, a rate gyro for detecting an angular velocity is used as a direction sensor. In this case, the direction of the vehicle is given by integrating the detected angular velocity. In this case, since the zero drift changes, errors accumulate in the direction of the vehicle obtained by integration. Therefore, when the stop detecting means 31 detects the stop of the vehicle, the drift calculating means 32 calculates the zero drift (ST3), and calculates the current position while reducing the drift during traveling (S3).
T1, ST2).

[0005]

However, in the above-described conventional on-vehicle navigation system using a rate gyro, the drift is calculated only when the vehicle is stopped. Therefore, when the vehicle travels over a long distance without stopping, the drift changes. There is a problem in that it cannot be grasped, directional errors are accumulated, and correct position calculation cannot be performed.

An object of the present invention is to solve such a conventional problem, and an object of the present invention is to provide an excellent in-vehicle navigation device capable of calculating a correct position even when the vehicle travels for a long time without stopping.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a first storage means for storing road map information, a distance sensor for detecting a traveling distance of a vehicle, and a driving direction of the vehicle. A direction sensor to be detected, a position of the vehicle on the road map, a first output coefficient of the distance sensor ,
Serial second direction sensor, the third storing the output coefficient and rewritable and to second storage means and the location information and the first and the second the vehicle stored in the storage means, the second , Third
Output coefficient, the output result of the distance sensor, and the azimuth sensor.
Based on the difference between the output potential of the vehicle at the moment
And position calculating means for calculating all certain existing position, the position
Location of all the vehicles calculated by the position calculation means
Information and road map information stored in the first storage means,
And refer to the location information of each vehicle.
To calculate all possible routes,
Judge what is the most appropriate driving route from among them,
No. to be used in the future corresponding to each of the routes
Calculate all the first, second and third output coefficients, and from them,
Determine what are the most appropriate first, second and third output coefficients.
Accuracy calculation means for cutting and the accuracy calculation means
Starting the vehicle on the travel route on the road map
Correction is made so that the point comes, and the accuracy calculation means
The first, second, and third outputs determined to be most appropriate by
JP further comprising a control means for rewriting order to force factor
It is a sign .

[0008]

According to the present invention, the position calculation is performed by the accuracy calculation means.
Location information of all vehicles calculated by the
And comparing the road map information stored in the first storage means with the road map information, and determining whether or not each vehicle is present.
Calculate all possible routes and find the most appropriate
At the same time you can determine what
1st, 2nd, and 1st to be used in the future corresponding to each route
Calculate all the output coefficients of 3 and find the most appropriate
Can determine what the first, second and third output coefficients are
You. Furthermore, the accuracy is calculated by the accuracy calculation means by the control means.
The starting point of the vehicle on the traveling route on the road map determined to be appropriate
And the accuracy calculation means
Write the first, second, and third output coefficients determined to be most appropriate.
Can be replaced . Also, by using a piezoelectric vibration type angular velocity sensor as the direction sensor , an inexpensive in-vehicle navigation device can be provided.

[0009]

FIG. 1 is a block diagram showing an on-vehicle navigation device according to an embodiment of the present invention. In FIG. 1, 11
Is a travel distance sensor (hereinafter referred to as a distance sensor) that calculates the rotational speed of the axle and detects the travel distance of the vehicle. When the rotational speed of the axle is N and the travel distance is S, S = a0N (a0 is the output A0 is not completely constant because it depends on the tire diameter, but is almost stable.

Reference numeral 12 denotes an azimuth sensor which is constituted by a piezoelectric vibration type angular velocity sensor and which detects the running azimuth of the vehicle by integrating its output. The output is V, the sampling time is t, and the rotation angle is θ. , Θ = Σ (a1Vt + a2t) (a1, a2 are output coefficients)
A1 and a2 are called sensitivity and offset, respectively.

13 is storage means for storing road map information;
Reference numeral 14 denotes a second storage unit that stores the position on the road map stored in the storage unit 13 and output coefficients of the distance sensor 11 and the direction sensor 12, and 15 denotes a second storage unit 1.
The position calculating means 16 calculates the possible position of the vehicle at that time based on the information stored in the information storage unit 4 and the output results of the distance sensor 11 and the azimuth sensor 12. Accuracy calculation means for calculating routes that can be traveled from the road map information in the storage means 13 and calculating errors that can be traveled on those paths as correction values of output coefficients of the distance sensor 11 and the direction sensor 12; The most reliable current position calculated by the calculating means 16 is displayed on the display means 18, and the accuracy calculating means 16
Of the position of the vehicle on the road map and the output coefficient of each of the distance sensor 11 and the azimuth sensor 12 calculated in the above, the control that rewrites the information stored in the second storage means 14 for the one that can be determined or corrected. Means.

Next, the operation of the above embodiment will be described with reference to FIG. According to the above embodiment, at all times, the position calculation means 15 is based on the outputs of the distance sensor 11 and the direction sensor 12 and the information stored in the second storage means 14.
All the possible positions of the vehicle are calculated with the maximum error allowed (ST11), and based on this information, all possible routes are calculated from the storage means 13 (ST12). The accuracy calculation means 16 calculates the
At the same time as calculating the correction value , the output coefficient of each of the distance sensor 11 and the azimuth sensor 12 when taking the route is calculated.
A correction value is also calculated. The end of the path will indicate the current position of the vehicle, so the position of the vehicle and
The correction values of the output coefficients of the distance sensor 11 and the direction sensor 12 are calculated simultaneously (ST13).
The control means 17 displays the most reliable one of these routes calculated by the accuracy calculation means 16 on the display means 18, as a map,
The current position and the traveling route are displayed to inform the driver of the current traveling state. The control unit 17 performs subsequent or error determination should be the starting point of the route calculated according to the correction value of the optimum route <br/> (ST14), if it is within permissible proper range, the vehicle in the second storage means 14 storing the position information of the newly rewritten information (ST15). Here, the accurate position information is not limited to the last end of the route, that is, the vehicle position at that time, and if a part of the route can be determined, it is determined as the position of the vehicle at the time that has been traced back. Then, it can be obtained as a starting point of the subsequent traveling route calculation. The output coefficients of the distance sensor 11 and the azimuth sensor 12, which are obtained simultaneously with the vehicle position information, are corrected to the most accurate values and stored in the second storage means 14 (ST16-1).
7). If the vehicle position cannot be determined in ST14, it is determined whether the azimuth can be corrected (ST1).
8) If possible, correct (ST17). This is to ensure a correction value of the output coefficient of the azimuth sensor 12 when there is no characteristic bend such that the position of the vehicle can be determined on the road, such as when the vehicle is running on a straight road for a long time.

In ST11-12, all possible vehicle positions and travel routes are calculated. However, the accuracy of road map information is increased, and the fluctuation range of the output coefficients of the distance sensor 11 and the direction sensor 12 is reduced. If the prediction can be made, the number of calculations is reduced, so that the calculation after ST13 is performed promptly. In this manner, the sensor output coefficient is corrected at any time during traveling on a road with a low stopping frequency, such as a highway, so that the position can be accurately calculated.

In general, at the time of rising, the sensor output coefficient greatly changes. In particular, in the case of a piezoelectric vibration type angular velocity sensor, the fluctuation of the offset is large and the accuracy of the position calculation is reduced.
Although it did not function sufficiently, in the present invention, since the sensor output coefficient is corrected at any time, the position can be accurately calculated.

[0015]

As is apparent from the above description, according to the present invention, the correction value of the sensor output coefficient is calculated simultaneously with the position calculation, and the correction of the sensor output coefficient is performed simultaneously with the determination of the position. Even if the vehicle travels continuously without time stop, the position can be accurately calculated.

[Brief description of the drawings]

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

FIG. 2 is a flowchart showing an operation example of the on-vehicle navigation device.

FIG. 3 is a block diagram showing a conventional in-vehicle navigation device.

FIG. 4 is a flowchart showing an operation example of the on-vehicle navigation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Distance sensor 12 Direction sensor 13 Road map storage means 14 Second storage means 15 Position calculation means 16 Accuracy calculation means 17 Control means 18 Display means

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroshi Takenaka 1006 Kadoma Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Masanori Yoshida 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-63-191018 (JP, A) JP-A-63-182519 (JP, A) JP-A-63-109315 (JP, A) JP-A-60-249012 (JP, A) JP-A-55-15505 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01C 21/00 G08G 1/0969 G09B 29/10

Claims (1)

(57) [Claims] A first storage unit for storing road map information; a distance sensor for detecting a traveling distance of the vehicle; an azimuth sensor for detecting a traveling direction of the vehicle; and a position of the vehicle on the road map. And the first output coefficient of the distance sensor and the
Serial second direction sensor, the third storing the output coefficient and rewritable and to second storage means and the location information and the first and the second the vehicle stored in the storage means, the second , Third
Output coefficient, the output result of the distance sensor, and the azimuth sensor.
Based on the difference between the output potential of the vehicle at the moment
And position calculating means for calculating all certain existing position, the position
Location of all the vehicles calculated by the position calculation means
Information and road map information stored in the first storage means,
And refer to the location information of each vehicle.
To calculate all possible routes,
Judge what is the most appropriate driving route from among them,
No. to be used in the future corresponding to each of the routes
Calculate all the first, second and third output coefficients, and from them,
Determine what are the most appropriate first, second and third output coefficients.
Accuracy calculation means for cutting and the accuracy calculation means
Starting the vehicle on the travel route on the road map
Correction is made so that the point comes, and the accuracy calculation means
The first, second, and third outputs determined to be most appropriate by
Vehicle navigation and control means for rewriting order to force factor.