JPH0776862B2 - Car navigation system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle-mounted navigation device, and more particularly to a GPS (Global Pos) that outputs coordinate data representing an absolute position of a vehicle.
sitioning System) The present invention relates to a vehicle-mounted navigation device having a receiver.

BACKGROUND ART In recent years, map data including road data obtained by digitizing each point on a road segment of a map is stored in a storage medium such as a CD-ROM and the current position of the vehicle is included while recognizing the current position of the vehicle. An in-vehicle navigation device has been developed that reads out a map data group of a certain area from a storage medium and displays it on the display as a map around the current location of the vehicle, and automatically displays the own vehicle position indicating the current location of the vehicle on the map, It is being put to practical use.

Such an on-vehicle navigation device has a configuration in which a traveling direction of the vehicle is obtained by a direction sensor and a traveling distance of the vehicle is obtained by a distance sensor, and the current position of the vehicle on the map is estimated from the traveling direction and the traveling distance. here,
Since both the azimuth data and the distance data obtained by the azimuth sensor and the distance sensor usually include an error of about several percent, the current position of the vehicle estimated from these data inevitably causes an error with respect to the actual traveling position. Will have.

Also, according to the longitude / latitude information obtained from the output data of the GPS receiver (hereinafter, referred to as GPS data), the absolute position can be estimated with a certain degree of accuracy. Therefore, the absolute position of the vehicle can be detected by this GPS receiver. An in-vehicle navigation device that estimates the current location is also being developed. this
Positioning by a GPS receiver is usually performed by receiving radio waves from three or four artificial satellites. That is, when receiving radio waves from three artificial satellites, positioning at a two-dimensional position (latitude, longitude) (hereinafter referred to as two-dimensional positioning)
Is performed, and 3 is received when the radio waves from the four satellites are received.
Positioning of the dimensional position (latitude, longitude, altitude) (hereinafter referred to as three-dimensional positioning) will be performed.

In a vehicle-mounted navigation device equipped with this GPS receiver, the reception position of the GPS receiver changes as the vehicle travels, so that radio waves from four artificial satellites can always be received for three-dimensional positioning. However, the altitude value cannot be obtained when the reception state deteriorates and the two-dimensional positioning is performed, so that it is not possible to accurately estimate the current position coordinates of the vehicle particularly in an area with a height difference.

As one of the solutions, there is a method of describing the altitude value in the map data. However, when it comes to generating advanced data, the amount of data becomes enormous,
There was a difficulty in feasibility. In addition, by entering the altitude value, the amount of data increases, the map range that can be stored in the recording medium becomes narrow, and the problem that the capacity of the memory that temporarily stores road data becomes large will occur. .

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an in-vehicle navigation device capable of accurately estimating the current position of a vehicle even if the reception state of a GPS receiver is poor and the data accuracy deteriorates due to two-dimensional positioning. The purpose is to provide.

[Configuration of the Invention] The vehicle-mounted navigation device according to the present invention includes a GPS receiver that outputs coordinate data representing the absolute position of the vehicle, and a plurality of road data that are obtained by digitizing each point on the road line segment of the map. And a reading means for reading the map data group from a storage medium in which a plurality of map data groups corresponding to the respective regions are stored, and the actual measurement while recognizing the actual measurement position of the vehicle based on the output data of the GPS receiver. An in-vehicle navigation device adapted to extract a map data group of an area within a certain range including the present location from the storage medium and display the map around the actually measured current location of the vehicle and the actually measured location on the display unit, wherein the GPS receiver Is a two-dimensional side position determination means, a provisional current location setting means for setting a provisional current location, coordinate data of the provisional current location, and output of the GPS receiver. The provisional altitude value setting means for obtaining the altitude value of the provisional current location based on the data, and the determination means for the GP
As long as it is determined that the S receiver is in the two-dimensional side position, the coordinate data of the estimated current position is obtained as the actually measured current position from the output data of the GPS receiver and the temporary set altitude value by the temporary altitude value setting means. It is composed of means.

The vehicle-mounted navigation device according to the present invention further includes means for obtaining coordinate data of a reference estimated present position from GPS data and a reference altitude value, and a neighboring road line segment data group representing a road segment near the reference estimated present position. Means for searching from a map data group, provisional altitude value setting means for setting a plurality of temporary altitude values different from the reference altitude value, and
A means for obtaining coordinate data of a plurality of temporary estimated current positions from GPS data and each of the plurality of temporary altitude values, and coordinate data of a temporary estimated current position which is the closest to the coordinate data in the neighboring road line segment data group. A selecting means for selecting from the coordinate data of the plurality of provisional estimated current locations, and a calculating means for calculating the altitude value of the estimated current value based on the provisional altitude value corresponding to the coordinate data of the selected provisional estimated current location, and When the two-dimensional positioning is judged by the judging means, it comprises a means for obtaining the coordinate data of the present location from the GPS data and the altitude value calculated by the calculating means.

[Operation of the Invention] In the vehicle-mounted navigation device according to the present invention, the GPS
While recognizing the current location of the vehicle based on the data, a map data group of a certain area including the current location is extracted from the storage medium and the map around the current location of the vehicle and the current location are displayed on the display unit. Is in the state of two-dimensional positioning, the altitude value of the provisional current position set manually or automatically is calculated, and the coordinate data of the estimated current position is calculated from this altitude value and GPS data.

Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a vehicle-mounted navigation device according to the present invention. In the figure, 1 is a direction sensor for detecting the traveling direction of the vehicle, 2 is an angular velocity sensor for detecting the angular velocity of the vehicle, 3 is a distance sensor for detecting the traveling distance of the vehicle, 4 is latitude and longitude information. It is a GPS receiver for detecting the absolute position of the vehicle from the
Each of these sensors (hereinafter, including GPS receiver)
The detection output of is supplied to the system controller 5. As the direction sensor 1, for example, a geomagnetic sensor that detects the traveling direction of the vehicle by using geomagnetism is used.

The system controller 5 receives the detection output of each sensor 1 to 4 as an input and performs an interface 6 for processing such as A / D (analog / digital) conversion, and various image data processing, and each is sequentially sent from the interface 6. A CPU (central processing circuit) 7 for calculating the traveling distance, traveling direction, and current position coordinates (longitude, latitude) of the vehicle based on the output data of the sensors 1 to 4, and various processing programs of this CPU 7 and other necessary RO with pre-written information
M (read only memory) 8 and RA for writing and reading information necessary for executing the program
And M (random access memory) 8.

As an external storage medium, for example, a read-only non-volatile storage medium such as a CD-ROM, and as a writable and readable non-volatile storage medium such as a DAT (digital
Audio tape) is used. The external storage medium is not limited to a CD-ROM or DAT, and a non-volatile storage medium such as an IC card can be used. The CD-ROM stores in advance map data obtained by digitizing (numericalizing) each point on the road of the map. This CD-RO
The information stored in M is read by the CD-ROM driver 10. The read output of the CD-ROM driver 10 is decoded by the CD-ROM decoder 11 and sent to the bus line L.

On the other hand, the DAT is used as a so-called backup memory, and recording or reading of information is performed by the DAT deck 12
Done by. Immediately before turning off the vehicle power
Information such as the vehicle's current position coordinates stored in RAM9 is stored as backup data in the DAT by being supplied to the DAT deck 12 via the DAT encoder / decoder 13, and when the vehicle power is turned on, the stored DAT information is stored in the DAT. Deck 12
Read by. The read information is stored in the RAM 9 by being sent to the bus line L via the DAT encoder / decoder 13.

The turning on and off of the vehicle power is detected by the detection circuit 14 which monitors the output level of the so-called accessory switch SW of the vehicle. Vehicle power from a battery (not shown) that has passed through the accessory switch SW is stabilized by the regulator 15 and supplied as power to each part of the device. The output voltage of the regulator 15 does not fall instantaneously when the accessory switch SW is turned off due to the time constant of the circuit, and backup data is stored in the DAT as the backup memory during this fall period.

When the vehicle is traveling, the CPU 7 calculates the traveling azimuth of the vehicle based on the output data of the azimuth sensor 1 at a predetermined cycle by a timer interruption, and the traveling distance and the traveling distance by interruption every constant distance traveling based on the output data of the distance sensor 3. The current position of the vehicle is estimated from the traveling direction, and G is received by the GPS reception interrupt.
The current position of the vehicle is estimated based on the latitude and longitude information obtained from the PS data, and the estimated current position or GPS based on the sensor data
Guess by data Collect map data of a certain area including the current location from the CD-ROM, and use this collected data in RAM9.
It is temporarily stored in and is supplied to the display device 16. As a method for obtaining the traveling direction of the vehicle based on the output data of the direction sensor 1, the method described in JP-A-62-130013 can be used.

The display device 16 includes a display 17 such as a CRT and a V (Video).
A graphic memory 18 including a RAM, a graphic controller 19 for drawing map data sent from the system controller 5 as image data in the graphic memory 18, and outputting the image data; and a graphic controller 19 for outputting the graphic data. The display controller 20 controls to display a map on the display 17 based on the image data. The input device 21 is composed of a keyboard and the like, and issues various commands to the system controller 5 by key input by the user.

Next, a processing procedure for estimating the current position of the vehicle, which is executed by the CPU 7 based on the GPS data, will be described with reference to the flowcharts of FIGS. 2A to 2C. Note that this subroutine reads the map data group of a certain area including the current position from the CD-ROM while recognizing the current position of the vehicle and displays it on the display 17 as a map around the current position of the vehicle, and on the map. It is assumed that the main routine (not shown) for displaying the current position of the vehicle is displayed and called at a predetermined cycle during execution.

First, the CPU 7 obtains the traveling amount (Δx, Δy) of the vehicle from each sensor data of the direction sensor 1 and the distance sensor 3 (step S1), and the traveling amount (Δx, Δx, per unit time).
Δy) is integrated (step S2), and this processing is performed in step S3.
Repeat until it is determined that GPS has been received. As a result, the traveling amount (ΔXs, ΔYs) of the vehicle from the time when the last GPS was received to the time when this GPS was received can be obtained.

When it is determined that GPS has been received, the CPU 7 determines whether the GPS receiver is in the three-dimensional positioning state (step S4) or the two-dimensional positioning state (step S5). This determination is performed based on the identification information sent from the GPS receiver, which is the three-dimensional positioning or the two-dimensional positioning. In the case of three-dimensional positioning, the CPU 7 obtains the coordinate data of the estimated present position based on the three-dimensional positioning data of the GPS receiver (step S6), and then shifts to step S30. In the case of two-dimensional positioning, the CPU 7 obtains the altitude value of the current location by various methods shown below,
The process of obtaining the coordinate data of the estimated present position is executed from this altitude value and the two-dimensional positioning data of the GPS receiver.

The CPU 7 first determines whether or not the provisional current location is designated by manual input (step S7). This provisional current location is designated by inputting a predetermined position on the map displayed on the display 17, for example, coordinates or points on the road line segment, using the cursor key of the input device 21. If the temporary current location is designated by manual input, the CPU 7 obtains the altitude value of the temporary current location from the coordinate data of the temporary current location obtained from the map data group of the map displayed on the display 17 and the two-dimensional positioning data (step S8). . If the temporary current location is not specified by manual input, the CPU 7 determines whether the vehicle has passed a singular point such as an intersection (step S9). If the singular point is passed, the CPU 7 sets the singular point as the provisional current position, and the altitude value of the provisional current position is calculated from the coordinate data of the singular point obtained from the map data group regarding the map displayed on the display 17 and the two-dimensional positioning data. (Step S1
0).

If no temporary current value is specified by manual input and no singular point is passed, the CPU 7 adds the vehicle travel amount (ΔXs, ΔYs) obtained in step S2 to the coordinate data of the previous estimated current position to obtain the coordinates. The data is used as the coordinate data of the estimated present position (step S11). Subsequently, the CPU 7 searches for a road line segment data group, which preferably represents the nearest road line segment with respect to the coordinate data of the estimated present location, from the map data group of a certain area centering on the present location (step S12). ). As a method for searching the nearest road line segment data group, the method described in JP-A-63-115004 can be used. Then, the CPU 7 is a distance from the estimated current position to the intersection coordinates of the perpendicular line to the nearest road line segment, that is, the shortest distance from the estimated current position on the nearest road line segment is below the predetermined value. It is determined whether or not there is (step S13), and if it is less than or equal to the predetermined value, the altitude value of the current location is obtained from the coordinate data of the intersection coordinates on the nearest road segment and the two-dimensional positioning data (step S14).

If the distance from the estimated current position to the intersection coordinates on the nearest road line segment exceeds a predetermined value, the CPU 7
Using h ₀ as the reference altitude value, the coordinate data of the reference estimated present position is obtained from this reference altitude value and the two-dimensional positioning data (step S1
5) A road line segment data group, which preferably represents the nearest road line segment with respect to the coordinate data of this reference estimated current location, is searched from a map data group of a certain area centering on the current location (step S16). , Coordinate coordinates of a perpendicular line from the reference estimated current position to the nearest road segment, that is, each coordinate data of the coordinates on the road segment closest to the reference estimated current position and the reference estimated current position Absolute value of the difference of SBN0
Is calculated (step S17).

Next, the CPU 17 sets the altitude value (h ₀ −h) obtained by subtracting the predetermined value h from the previous altitude value h ₀ as the first provisional altitude value, and based on this first provisional altitude value and the two-dimensional positioning data, The coordinate data of the first provisional estimated current position is obtained (step S18), and the intersection coordinates of the perpendicular to the nearest road segment previously searched from the first provisional estimated current position are obtained (step S19). 1 Provisional Guessing The distance SBN1 from the present location is obtained (step S20). Subsequently, the CPU 7 determines whether or not the distance SBN1 is smaller than the previous absolute difference value SBN0 (step S2
1), if SBN1 <SBN0, the altitude of current location h _n (Step S22).

If SBN1 ≧ SBN0, the CPU 7 sets the previous altitude value h ₀ to the predetermined value h
The altitude value (h ₀ + h) obtained by adding the second temporary altitude value to the second temporary altitude value is used as the second temporary altitude value.
The provisional estimated present position is obtained (step S23), the intersection coordinates of the perpendicular line from the second provisional estimated present position to the nearest road segment obtained in step S16 are obtained (step S24), and the second provisional estimation up to this intersection coordinate is obtained. The distance SBN2 from the current position is calculated (step S25). Then, the CPU 7 determines whether or not the distance SBN2 is smaller than the previous absolute difference value SBN0 (step SBN2).
S26), if SBN2 <SBN0, the altitude value h _n at the current location is (Step S27), if SBN2 ≧ SBN0, the previous altitude value h ₀ is set as the current altitude value h _n (step S2)
8).

In other words, in steps S15 to S28, the GP
From the S data and the reference altitude value (for example, the previous altitude value h ₀ ), the coordinate data of the reference estimated current position is obtained, and the road line segment data that preferably represents the nearest road segment to the coordinate data of the reference estimated current position. The group is searched from the map data group, and, for example, the first and second provisional altitude values different from the reference altitude value are set, and the coordinates of the first and second provisional estimated current positions are set from each of these temporary altitude values and GPS data. A process of obtaining data and calculating the altitude value of the current position based on the temporary altitude value which gives the temporary estimated current position of the nearest to the coordinate on the nearest road segment is performed. When the reference estimated current position is closer to the coordinates on the nearest road segment than the first and second provisional estimated current positions, the reference altitude value is set as the estimated current position altitude value.

Step S8, Step S10, Step S14, Step S27
Alternatively, when the altitude value of the current location is obtained in step S28, the CPU
7 obtains the coordinate data of the estimated current position from this altitude value and the two-dimensional positioning data (step S29), clears the travel amount (ΔXs, ΔYs) obtained in step S2 (step S30), and calculates the coordinate data of the estimated current position. This value is the previous value (step
In step S31, the obtained current altitude value is set as the previous altitude value (step S32).

With the above, a series of processes for estimating the current position of the vehicle is completed.

In the above embodiment, the previous altitude value was set as the reference altitude value in step S15, but the present invention is not limited to this, and a certain empirically obtained value may be set.

Further, in the above embodiment, two values of the reference altitude value ± h are set as the temporary altitude value to obtain the coordinate data of the two temporary estimated current positions, but it is needless to say that the coordinate data may be 3 or more. is there.

Effects of the Invention As described above, in the vehicle-mounted navigation device according to the present invention, while recognizing the current position of the vehicle based on the GPS data, the map data group of a certain range of area including the current position is extracted from the storage medium and stored in the vehicle. The GPS receiver will display the map around the present location of the
When in the dimensional positioning state, the altitude value of the provisional current position set manually or automatically is calculated, and the coordinate data of the estimated current position is calculated from this altitude value and GPS data. Is poorly received, 2
Even if the data accuracy deteriorates due to dimensional positioning, the current position of the vehicle can be accurately estimated.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an in-vehicle navigation device according to the present invention, and FIGS. 2A to 2C are flow charts showing a processing procedure executed by the CPU to determine the current position coordinates of the vehicle. Explanation of main part code 1 …… Direction sensor, 3 …… Distance sensor 4 …… GPS receiver 5 …… System controller 10 …… CD-ROM driver 17 …… Display

Front page continuation (72) Inventor Atsuhiko Fukushima 25-1, Nishimachi, Yamada, Kawagoe, Saitama Prefecture 1 Pioneer Co., Ltd. Kawagoe factory (72) Inventor, Kazuhiro Akiyama 25, Nishimachi, Kawagoe, Saitama Prefecture 1 Pioneer shares Company Kawagoe Factory (56) Reference JP-A-56-17460 (JP, A) JP-A-1-66685 (JP, A)

Claims (8)

[Claims] 1. A GPS receiver for outputting coordinate data representing an absolute position of a vehicle, and a plurality of road data including road data obtained by digitizing points on a road segment of a map and corresponding to a plurality of regions. And a reading means for reading the map data group from a storage medium in which the map data group is stored, while recognizing the actually measured current position of the vehicle based on the output data of the GPS receiver An in-vehicle navigation device configured to extract a map data group from the storage medium and display a map around a vehicle's actual measurement location and an actual measurement location on a display unit, wherein the GPS receiver is in a two-dimensional side position. Determination means for determining that there is, provisional current location setting means for setting the provisional current location, and the height of the provisional current location based on the coordinate data of the provisional current location and the output data of the GPS receiver. Provisional altitude value setting means for obtaining a value, and output data of the GPS receiver and provisional setting by the provisional altitude value setting means as long as the determining means determines that the GPS receiver is in the two-dimensional side position. A vehicle-mounted navigation device comprising: means for obtaining coordinate data of an estimated current position from the altitude value as the actually measured current position. 2. The vehicle-mounted navigation according to claim 1, wherein the provisional current location setting means comprises a manual input means for manually inputting a predetermined position on the map displayed on the display unit as the provisional current location. apparatus. 3. The vehicle-mounted navigation device according to claim 1, wherein the temporary current position setting means detects that the vehicle has passed a singular point and sets the position of the singular point at that time as the temporary current position. . 4. The provisional current position setting means includes a distance sensor for detecting a traveling distance of a vehicle, an azimuth sensor for detecting a traveling azimuth of the vehicle, and the estimation based on output data of the distance sensor and the azimuth sensor. A means for obtaining coordinate data of the current location, and means for searching a neighboring road line segment data group representing a road segment near the estimated current location from the map data group, 2. The vehicle-mounted navigation device according to claim 1, wherein the coordinate data in the vicinity of the coordinate data of the estimated present position among the coordinate data of <3> is set as the coordinate data of the confirmed present position. 5. A GPS receiver for outputting coordinate data representing an absolute position of a vehicle, and a plurality of road data including road data obtained by digitizing each point on a road segment of a map and corresponding to a plurality of regions. And a reading means for reading the map data group from a storage medium in which the map data group is stored, and while recognizing the current position of the vehicle based on the output data of the GPS receiver, map data of a certain range including the current position An in-vehicle navigation device configured to extract a group from the storage medium and display a map around a current position of a vehicle and a current position on a display unit, wherein the GPS receiver is in a two-dimensional positioning state. Determining means, means for obtaining coordinate data of the reference estimated current position from the output data of the GPS receiver and the reference altitude value, and a neighborhood road line representing a road segment near the reference estimated current position Means for searching minute data group from the map data group, provisional altitude value setting means for setting a plurality of provisional altitude values different from the reference altitude value, output data of the GPS receiver and the plurality of provisional altitude values A means for obtaining coordinate data of a plurality of provisional estimated present positions from each of the altitude values, and coordinate data of the provisional estimated present position which is the closest to the coordinate data in the neighboring road line segment data group Selecting means for selecting from the coordinate data of the values; calculating means for calculating the altitude value of the estimated current position based on the temporary altitude value corresponding to the coordinate data of the temporary estimated estimated current position selected by the selecting means; An in-vehicle navigation system comprising means for obtaining coordinate data of the current location from output data of the GPS receiver and altitude values calculated by the calculating means at the time of dimensional positioning determination. Shon apparatus. 6. The vehicle-mounted vehicle according to claim 5, wherein the temporary altitude value setting means sets the value obtained by adding or subtracting an integral multiple of a predetermined value to the reference altitude value as the temporary altitude value. Navigation device. 7. The calculating means sets the reference altitude value as an altitude value of a finalized current position when the reference estimated current position is closer than the plurality of provisional estimated current positions. The in-vehicle navigation device described. 8. The vehicle-mounted navigation device according to claim 5, wherein the reference altitude value is a previous altitude value.