JP2924522B2 - 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 in-vehicle navigation device for displaying the position and orientation of a vehicle and map information around the vehicle.

[0002]

2. Description of the Related Art Conventionally, this kind of in-vehicle navigation device generally has a configuration as shown in FIG. The configuration and operation will be described below. In FIG. 4, data of an angular velocity sensor 101 such as a geomagnetic sensor and a distance sensor 102 are input to a CPU 104 from an input interface 103 to determine a vehicle position, a vehicle azimuth, and a running locus, and a GPS receiver obtained through a communication interface 105 By comparing the absolute position information of 106 with the map data of the CD-ROM 107, the estimated vehicle position can be calculated, and the vehicle position on the map can be displayed on the display 109 via the image processor 108.

[0003]

However, in the above-mentioned conventional on-vehicle navigation device, it is necessary to set an initial position and an initial azimuth of the vehicle at the time of initial start-up. If the azimuth was not known, the initial position and azimuth could not be set. Also, if there is no opportunity to correct the position or direction over a long distance, such as driving on a new road that is not on the map, errors will be accumulated in the calculated vehicle position and vehicle direction,
There was a problem that the correct vehicle position and vehicle direction were lost.

Conventionally, to solve these problems, G
There is a method of correcting the vehicle position by adding a device for calculating the current position based on external information such as PS, but the GPS has only the position information and cannot correct the vehicle direction (GP
Although there is S azimuth information, the reliability is low below a certain speed.) Further, there is a problem that GPS position information may be disturbed by a multipath, a combination of satellites, or the like, and it is necessary to select only valid GPS azimuth data.

The present invention has been made to solve the above-mentioned conventional problems, and does not require the user of the vehicle to set the initial position and the initial direction of the vehicle. It is an object of the present invention to provide an excellent in-vehicle navigation device that can be reset without losing sight.

[0006]

According to the present invention, in order to achieve the above object, the independent position calculated by the independent position calculating means is calculated by the GPS position calculating means at an arbitrary distance or at an arbitrary time. Position correcting means for correcting to a GPS position, and a GP previously corrected by the position correcting means
The slope of the straight line connecting the S position and the GPS position calculated this time, and the slope of the straight line connecting the GPS position previously corrected by the position correction means and the current independent position calculated by the independent position calculation means are calculated. and azimuth difference calculation means for calculating a difference, and weighting means for weighting relative difference calculated by the direction calculating means, the current self orientation calculated by the autonomous orientation calculation unit, by the weighting with means Heavy
And a traveling azimuth correcting means for correcting the azimuth with the weighted azimuth difference.
GPS position information and azimuth information containing error components
By repeating the process over a broadcast to a plurality of times, the orientation of Osamu raise the reliability of the GPS data includes an error component
Seiryo can be determined is also of the.

[0007]

[0008]

Therefore, according to the present invention, the initial position setting and azimuth setting are not required by GPS, and even if there is no opportunity to correct the position and azimuth over a long distance during traveling, only the vehicle position is determined by GPS. In addition, it has an effect that the vehicle direction can be corrected.

[0009]

1 to 3 show an embodiment of the present invention.
This will be described in detail with reference to FIG.

FIG. 1 is a block diagram of this embodiment, FIG. 2 is an example of a flowchart, and FIG. 3 is an example of an explanatory diagram of a direction calculating means.

In FIG. 1, 1 is a GPS receiver and 2 is a G
It is a PS position calculating unit that analyzes data transmitted from the GPS receiver 1 and calculates a GPS receiving position. Reference numeral 3 denotes GPS position holding means for holding the GPS position at the time of the last correction, and 4 denotes GPS position absolute azimuth calculation means for calculating the absolute azimuth between the current GPS position and the GPS reception position at the last correction. is there. Reference numeral 5 denotes a speed sensor, and a speed detecting means 6 detects a vehicle speed based on data from the speed sensor 5. Reference numeral 7 denotes a moving distance calculating unit that calculates a moving distance of the vehicle based on data from the speed sensor 5. Reference numeral 8 denotes an angular velocity sensor, and an independent azimuth change detecting unit 9 calculates an absolute azimuth between GPS reception positions based on data from the angular velocity sensor 8. 10 is an independent position calculating means,
The current independent position is calculated from the output of the moving distance calculating means 7 and the independent azimuth change detecting means 9. Reference numeral 11 denotes a self-sustained position holding unit that holds the previous self-standing position, and 12 denotes a self-standing position absolute azimuth calculation unit that calculates the absolute azimuth between the previous and current self-standing positions. Numeral 13 denotes an azimuth difference calculating means.
To obtain the azimuth correction amount. Reference numeral 14 denotes an independent traveling azimuth calculating means for calculating an independent traveling azimuth, and reference numeral 15 denotes a traveling azimuth correcting means.

Next, the operation of the above embodiment will be described. In FIG. 1, the GPS position calculating means 2
The data transmitted from the S receiver 1 is analyzed to calculate the GPS reception position, and the GPS position calculated this time and the GPS position at the time of the last correction obtained from the GPS position holding means 3 are used to calculate the GPS position.
The absolute azimuth between the GPS receiving positions is calculated by the absolute azimuth calculating unit 4 between the PS positions.

On the other hand, the vehicle speed is detected by the speed detecting means 6 from the data of the speed sensor 5, and the moving distance calculating means 7 is used.
, The moving distance by the speed sensor 5 is calculated. Also,
The azimuth change amount is detected by the independent azimuth change detection means 9 from the data of the angular velocity sensor 8. The current independent position is calculated by the independent position calculating means 10 from the obtained moving distance and the azimuth change amount, and the absolute azimuth calculating means 12 between the previous independent position held by the independent position holding means 11 and the current independent position is used. Calculate the absolute azimuth between the previous and current independent positions.

Further, an absolute azimuth calculation means between GPS positions 4
Azimuth between GPS reception positions determined by
The azimuth correction amount is obtained by the azimuth difference calculating means 13 from the absolute azimuth between the previous and current independent positions by the absolute azimuth calculating means 12 between independent positions, and the independent running azimuth is calculated by the independent running azimuth calculating means 14.

Here, if the moving distance obtained by the moving distance detecting means 7 is equal to or more than a predetermined value, it is determined that the corrected azimuth by GPS is effective, and the traveling azimuth correcting means 15 corrects the self-sustained running azimuth.

FIG. 2 is a flowchart showing a control flow for correcting the self-sustained running direction. The position is corrected by GPS at any time or at any distance, and step 2 is performed.
In step 1, it is determined whether the m-th position correction has occurred. In step 22, it is determined whether the n-th position correction has occurred. Next, in step 24, it is determined whether or not the m-th and n-th corrected positions by GPS are separated by a distance equal to or greater than a specified value. If not, the position correction by GPS is continued. If the distance is more than the specified distance, the process proceeds to step 26, where n
It is determined whether or not the corrected position by the GPS and the self-sustained traveling position at the time of the n-th correction are separated by a specified value or more. If the direction is corrected and the vehicle is not separated by more than the prescribed distance, the running direction of the vehicle is not corrected.
Return to

Next, referring to the vector diagram shown in FIG.
The correction of the vertical running direction will be described.

A (X _m , Y _m ) is the corrected position (starting point of self-sustained traveling) by the previous GPS, B (X _GPSn , Y _GPSn ) is the corrected position by the current GPS, and C is the self-sustained traveling position at this time. (X _n , Y _n ), the absolute azimuth of the straight line connecting the two GPS corrected positions is θ _AB , the absolute azimuth of the straight line connecting the previous GPS corrected position and the self-standing position at the time of this correction is θ _AC , _Let θ _{n (old) be} the self-sustained running azimuth before correction and θ _{n ( new)} be the self-sustained running azimuth after correction, θ _AB and θ _AC are expressed by the following equations.

Θ _AB = tan-1 ｛(Y _GPSn -Y _m ) / (X _GPSn -X _m )｝ θ _AC = tan-1 ｛(Y _n -Y _m ) / (X _n -X _m )｝ And m and n (n> m) are arbitrary integers.

Azimuth correction amount calculated from θAB and θAC
dθ is dθ = {β / (α + β)} × (θAB−θAC) where α is a positive number less than 1 and is an absolute value.
Is a weighting factor for the position θAB, β is a positive
Is a weighting factor for the absolute azimuth θAC in the form of α + β
= 1. Therefore, θn (new) is expressed by the following equation.

Θ _{n (new)} = θ _{n (old)} + dθ where the lower limit value of the distance between the two GPS points AB is
L _{AC_min} , the lower limit of the distance between BC at the time of this correction is L
_{Assuming BC_min} , the distance L between the two GPS points AB
_{When AC} satisfies the following formula, L _AC > L _{AC_min,} and the distance between BCs at the time of this correction L _BC satisfies the following formula, L _BC > L _{BC_min} , the corrected azimuth by GPS is considered to be valid and the self-sustained driving azimuth To correct the running direction of the vehicle.

As described above, according to the above embodiment, the position is corrected by the GPS at an arbitrary time or at an arbitrary distance, and the corrected position by the m-th GPS and the n-th GPS are corrected.
Azimuth of the straight line connecting the correction position by GPS and the m-th GPS
The correction amount of the self-sustained traveling azimuth is calculated from the difference between the azimuth of a straight line connecting the position at the time of the nth GPS correction of the self-sustained traveling starting from the m-th corrected position and the m-th corrected position. Correction position is over specified value and nth GPS
If the corrected position and the self-sustained traveling position at the time of the n-th correction are equal to or larger than the specified value, the traveling direction of the vehicle can be corrected simultaneously with the n-th position correction.

[0023] Particularly, in the above embodiment, the present self orientation calculated by the autonomous orientation calculation unit, weight at only means weighting
Since the vehicle is equipped with a traveling direction correction means that corrects with the found direction difference , the direction correction amount can be calculated by repeating the process.
It can be gradually converged.

[0024]

According to the present invention, a weighting means for weighting the difference calculated by the azimuth calculating means is provided ,
Now times independence orientation calculated by the position calculating means, for modifying azimuth difference weighted with weighting means, error
Position information of the GPS that includes the components, GPS Day by azimuth information to iterate over multiple times
The amount of azimuth correction by increasing the reliability of the data
Monodea Ru.

[Brief description of the drawings]

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

FIG. 2 is a flowchart showing a control flow for correcting the self-sustained running direction of the device.

FIG. 3 is an explanatory diagram showing a calculation method of an azimuth calculation unit of the apparatus.

FIG. 4 is a block diagram of a conventional in-vehicle navigation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 GPS receiver 2 GPS position calculation means 3 GPS position holding means 4 GPS position absolute azimuth calculation means 5 Speed sensor 6 Speed detection means 7 Moving distance calculation means 8 Angular velocity sensor 9 Independence azimuth change detection means 10 Independence position calculation means 11 Independence Position holding means 12 Absolute azimuth calculating means between independent positions 13 Azimuth difference calculating means 14 Independent running azimuth calculating means 15 Running azimuth correcting means

Claims (3)

(57) [Claims] 1. A position correcting means for correcting an independent position calculated by an independent position calculating means to a GPS position calculated by a GPS position calculating means at an arbitrary distance or at an arbitrary time; G modified last time
The inclination of the straight line connecting the PS position and the GPS position calculated this time and the inclination of the straight line connecting the GPS position previously corrected by the position correction means and the current independent position calculated by the independent position calculation means are calculated. The azimuth difference calculating means for calculating the difference, the weighting means for weighting the difference calculated by the azimuth calculating means , and the current independent azimuth calculated by the independent azimuth calculating means , Traveling azimuth correction means for correcting with the azimuth difference weighted by the weighting means;
Car mounting for the navigation device in which comprises a. 2. The traveling azimuth correcting means corrects the running direction when the distance between the previous GPS position calculated by the GPS position calculating means and the current GPS position is equal to or greater than a specified value. Item 4. An in-vehicle navigation device according to item 1. 3. When the distance between the current GPS position calculated by the GPS position calculating means and the current independent position calculated by the independent position calculating means is equal to or greater than a specified value, the running azimuth is corrected by the running azimuth correcting means. 2. The in-vehicle navigation device according to claim 1, wherein the navigation device is modified.