JPH08334366A - Present location calculating device - Google Patents

Abstract

PURPOSE: To prevent the malfunction of a hybrid present location calculating device which combinationally uses the GPS and map matching in the calculation of the present location of its own vehicle associated with the map matching when the vehicle enters a service area or parking area provided along a highway from the highway. CONSTITUTION: A microprocessor 24 judges whether its own vehicle enters service area or parking area provided along a highway from the highway and inhibits the map matching function of a map matching means at least during the period until the vehicle returns to the highway after entering the service area or parking area. In addition, the microprocessor 24 also inhibits a GPS receiver 29 from calculating the present location of the vehicle at least during the inhibiting period of the map matching function and uses the virtual present location determined before executing map matching as the present location of the vehicle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mounted on a moving body such as a vehicle and measures the traveling distance and traveling direction of the moving body.
Accordingly, the present invention relates to a current position calculation device that calculates the current position of the moving body, and more specifically, a current position calculation that calculates the current position of the moving body when the moving body exists on an expressway. It relates to the device.

[0002]

2. Description of the Related Art Conventionally, in a current position calculating apparatus for calculating the current position of a vehicle traveling on a road, the current position of the vehicle is the traveling direction of the vehicle measured by a direction sensor such as a gyro and a vehicle speed sensor or It is calculated based on the traveling distance of the vehicle measured by the distance sensor.

The traveling distance of the vehicle is generally measured by measuring the output shaft of the transmission or the rotation speed of the tire, and the distance is a distance that the vehicle travels per rotation of the tire. It is calculated by multiplying by.

Further, in order to correct the error of the current position obtained from the traveling direction and traveling distance of the vehicle as described above, as described in JP-A-63-148115, based on the traveling distance and the direction change amount. The estimated position of the vehicle determined and the amount of error based on the error of the road map are obtained, and the estimated position is registered as the self-position corresponding to all the roads located within the range of the amount of error centered on the estimated position. However, a technique is disclosed in which the correlation coefficient of each of the registered estimated positions for each road is calculated and the estimated position corresponding to the correlation coefficient indicating that the error for the road is the smallest is the current position.
Further, in Japanese Examined Patent Publication No. 1-46004, the difference between the azimuth formed by a straight line connecting the folding points in the map information that approximates the road on the map by a polygonal line and the azimuth detected by the azimuth detector is within a certain angle. If so, a technique for determining that the vehicle is moving forward on the road between the break points is disclosed. As described in these publications, there is known a so-called map matching technique that corrects the obtained current position of the vehicle so as to match the road, and this map matching technique is used to calculate the current position. The accuracy can be increased.

On the other hand, as a technique for obtaining the current position, there is also known a technique for calculating the current position by using radio waves from satellites. GPS and the like are known as typical systems of such technology.

Now, the map matching technique described above,
Comparing the technologies that use GPS, it cannot be expected that the technology that uses GPS can obtain the current position with high accuracy, but the technology that uses map matching does not cause a large error in the current position, and the technology that uses map matching has high accuracy. However, on the other hand, it has a characteristic that the position may be greatly incorrect.

Therefore, the advantages of both technologies are used in combination.

In such a hybrid current position calculating device, for example, when the difference between the position obtained by map matching and the position obtained by GPS is small, the current position obtained by map matching is adopted and the position is calculated. When the deviation is large, the current position calculated by the GPS is adopted, so that the current position can be calculated with high accuracy and without a large error in the current position.

[0009]

By the way, when a vehicle enters a service area or a parking area on an expressway, or when the vehicle returns from the service area or the parking area to the main line of the expressway, map matching is performed. On the contrary, the current position may be unclear or unstable. That is, when map matching is performed due to a change in the vehicle direction caused by the vehicle turning in the service area or the parking area, the device determines that the road (main line or side road) other than the road where the vehicle is currently located. There is a risk of causing a malfunction such as matching the current position to a road or the like, or jumping the current position between a plurality of roads. In particular, when performing map matching that also considers the connection relationship between the road where the previous current position of the road is located and the road where the current current position of this time is located, once the device passes the current position near the highway, When the vehicle is matched with the existing side road, it may be difficult to match the current position again to the expressway, which is the road on which the vehicle originally travels.

Therefore, the present invention uses map matching and G
In a hybrid current position calculation device that also uses PS, a current position calculation device that does not erroneously calculate the current position of the vehicle even when the vehicle enters a service area or a parking area of a highway. The purpose is to provide.

[0011]

[Means for Solving the Problems] To achieve the above object,
The present invention is a current position calculation device mounted on a vehicle for calculating the current position of the vehicle, the satellite use current position calculation means for calculating the current position based on a radio wave received from a satellite, and at least an ordinary road. Means for storing map data representing a road map, including road data including data indicating whether the vehicle is an expressway, a direction detecting means for detecting a traveling direction of the vehicle, and a distance calculating means for calculating a traveling distance of the vehicle. , A virtual current position is obtained based on the traveling direction detected by the direction detecting means and the traveling distance calculated by the distance calculating means, and the virtual current position and the road data included in the map data are obtained. If there is a position on the road whose reliability as the current position is higher than the reliability of the virtual current position as the current position, the position on the road with the highest reliability is determined. If there is no position on the road that is estimated as the current position and the reliability as the current position is higher than the reliability as the current position of the virtual current position, there is a map matching unit that estimates the virtual current position as the current position. A current position determining unit that selects one of the current position estimated by the map matching unit and the current position calculated by the satellite using current position calculating unit according to a predetermined criterion, and determines the final current position. And whether the vehicle has entered the service area or the parking area from the main line of the highway and whether the vehicle has returned to the main line from the service area or the parking area based on the estimated current position and the road data. Area determining means for determining, and the predetermined criterion is the virtual current by the map matching means. If the location is estimated as the current position, than in other cases, satellite-based current position calculating means has calculated the current position is the final as-determined criteria likely to be determined as the current position,
The map matching means unconditionally estimates the virtual current position as the current position from the time the vehicle enters the service area or the parking area until it returns to the main line, and the current position determination means at least the It is characterized in that the current position estimated by the map matching means is unconditionally determined as the final current position during the period including the time from entering the service area or the parking area until returning to the main line. A current position calculation device is provided.

[0012]

In the present invention, the presence of the service area or the parking area is detected based on the current position data and the road data while the vehicle is traveling on the highway, and the entry into the area is detected, and at least the area is entered. From then to returning to the main line, at least in this area, the function of matching the current position to the road by the map matching is suppressed, and the virtual current position obtained based on the traveling direction and the traveled distance is determined by the map matching means. , So that it is estimated as the current position.
As a result, it is possible to prevent an erroneous operation of the current position calculation due to map matching that occurs when the vehicle enters the area.

Here, normally, when the virtual current position is estimated as the current position by the map matching means, the virtual current position does not match the road map. Therefore, the virtual current position estimated as the current position is estimated. The reliability of the position is lower than the reliability of the current position of the position matched on the road estimated as the current position. Therefore, in the present invention, normally, when the virtual current position is estimated as the current position by the map matching means, the current position calculated by the satellite use current position calculation means is the final position compared to other cases. The current position is easily determined.

However, in this case, since the reliability cannot be measured depending on the matching degree with the road map, the map matching means is controlled so as to estimate the virtual current position as the current position regardless of the reliability. Even in the service area or the parking area, the current position calculated by the satellite using current position calculating means is likely to be determined as the final current position.

Therefore, in the present invention, further, in the service area or the parking area, the map matching means is unconditionally included during the period from entering the service area or the parking area to returning to the main line. The current position estimated by is determined as the final current position.

With this, it is possible to prevent the malfunction of the current position calculation due to the map matching caused by the entry into the area, and to deal with it by using the virtual current position data during that period. Note that the distance traveled in the area is not very large, and the error in the measured distance traveled during that time is small.Therefore, the error in the virtual current position relative to the actual position is It can be expected to be smaller, and when returning to the main line and restarting map matching again, it can be expected that the current position will immediately return to the main line of the expressway.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of the present position calculating apparatus according to the embodiment of the present invention. As shown in FIG. 1, the present position calculation device 10 includes an angular velocity sensor 11 that detects a change in the heading by detecting the yaw rate of the vehicle, and a direction sensor 12 that detects the heading of the vehicle by detecting the geomagnetism. And a vehicle speed sensor 13 that outputs pulses at time intervals proportional to the rotation speed of the output shaft of the vehicle transmission. Also, GPS
Calculate current position based on radio waves received from satellite G
A PS receiver 29 is provided.

Also, a display 17 for displaying a map around the current position, a mark indicating the current position, etc., a switch 14 for accepting from the (driver) a command for switching the scale of the map displayed on the display 17, and a digital map. CD-ROM 15 for storing data and its CD
A driver 16 for reading map data from the ROM 15. Further, the controller 18 for controlling the operation of each peripheral device described above is provided. In the present embodiment, the digital map data described above includes road data composed of coordinates indicating the ends of a plurality of line segments,
Alternatively, it includes road width data indicating the road width of the road, a highway flag indicating whether the road is a highway or a general road, and the like.

The controller 18 includes an A / D converter 19 for converting the signal (analog) of the angular velocity sensor 11 into a digital signal, and an A / D converter 20 for converting the signal (analog) of the azimuth sensor 12 into a digital signal. , Vehicle speed sensor 13
A counter 26 that counts the number of pulses output from the device every 0.1 seconds, a parallel I / O 21 that inputs whether or not the switch 14 is pressed, and a DMA (Direct) that transfers the map data read from the CD-ROM 15. Memory Acces
s) It has a controller 22 and a display processor 23 for displaying a map image on the display 17.

The controller 18 also has a microprocessor 24 and a memory 25. The microprocessor 24 uses the current position calculated by the GPS receiver 29 and the angular velocity sensor 11 obtained via the A / D converter 19.
Direction signal 12 obtained via the A / D converter 20
Signal, the number of output pulses of the vehicle speed sensor 13 counted by the counter 26, the presence / absence of pressing of the switch 14 input via the parallel I / O 21, and the map data from the CD-ROM 15 obtained via the DMA controller 22. It accepts, processes based on those signals, calculates the current position of the vehicle, and displays it on the display 17 via the display processor 23. This vehicle position display is shown in FIG.
As shown in FIG. 5, the arrow mark or the like is superimposed and displayed on the map already displayed on the display 17. This allows the user to know the current position of the vehicle on the map. The memory 25 includes a ROM that stores a program or the like that defines the contents of processing (described later) for realizing such an operation, and a RAM that is used as a work area when the microprocessor 24 performs the processing. There is.

The operation of the present position calculation device 10 thus configured will be described below. The operation of the device 10 is
Generally, there are three processes: a process of calculating a traveling direction and a traveling distance of the vehicle, a process of determining the current position of the vehicle from the calculated traveling direction and distance, and a process of displaying the obtained vehicle position and orientation. These can be divided into processes, and these will be sequentially described.

FIG. 3 illustrates the flow of processing for calculating the traveling direction and traveling distance of the vehicle.

This processing is carried out at a constant cycle, for example 100 m.
This is a routine of the microprocessor 24 that is activated and executed for each S.

In this routine, first, the A / D converter 1
The output value of the angular velocity sensor 11 is read from 9 (step 401). Since the azimuth change is output as the output value of the angular velocity sensor 11, only a relative value in the traveling direction of the vehicle can be detected. Therefore, next, the output value of the azimuth sensor 12 is read from the A / D converter 20 (step 40
2) The estimated azimuth of the vehicle is determined using the absolute azimuth calculated from the output value of the azimuth sensor 12 and the azimuth change (angular velocity output) output from the gyro 11 (step 403).

This azimuth determination can be performed, for example, for a long time,
When the vehicle speed is low, the error of the angular velocity sensor is large, so
When the vehicle speed is low for a certain period of time or more, a method of using only the azimuth sensor azimuth is used.

Next, the number of pulses output from the vehicle speed sensor 13 is counted by the counter 26 every 0.1 seconds, and the counted value is read (step 404). By multiplying the read value by the distance coefficient, the distance advanced in 0.1 second is obtained (step 405).

Next, the traveling distance value per 0.1 second thus obtained is integrated with the previously obtained value,
It is checked whether the traveling distance of the vehicle has reached 20 m (step 406), and if it is less than 20 m (step 406).
No), the process of this time is ended and a new process is started.

As a result of the traveling distance calculation processing, when the accumulated traveling distance becomes a constant distance, for example, 20 m (Yes in step 406), the traveling direction and traveling distance (20 m) at that time are output (step). 407). In step 407, the cumulative distance is further initialized, and the cumulative traveling distance is newly started.

Next, the process of calculating the virtual current position of the vehicle based on the calculated traveling direction and traveling distance and obtaining the candidate points of the vehicle based on the calculated virtual current position will be described.

FIG. 4 shows the flow of this processing.

This processing is a routine of the microprocessor 24 which is started and executed in response to the output of the traveling direction and traveling distance from FIG. That is, this process is started every time the vehicle advances 20 m.

In this process, first, step 40
The traveling direction and traveling distance output in 7 are read (step 501). Next, based on those values, the amount of movement of the vehicle is obtained separately in the latitude and longitude directions. Further, the movement amount in each of these directions is added to the position of the vehicle candidate point obtained in the previous processing to obtain the virtual current position (A) which is the position where the current vehicle is estimated to exist (step 502). Details of this candidate point will be described later.

If the position of the previously obtained candidate point does not exist, such as immediately after the start of the apparatus, the position set separately is used as the position of the previously obtained candidate point and the virtual current position (A) is used. Ask for.

Next, a map around the obtained virtual current position (A) is obtained from the CD-ROM 15 by the drivers 16 and D.
The road data (line segment) read out through the MA controller 23 and within a preset distance D centered on the virtual current position (A) is selected and taken out (step 503).

As described above, in this embodiment, the road data is approximated by a plurality of line segments 51 to 55 connecting two points as shown in FIG.
The one represented by the coordinates of the start point and the end point is used. For example, the line segment 53 has its starting point (x3, y3)
And the end point (x4, y4).

Following step 503, it is confirmed whether the map matching suppression flag is 1 (step 51).
0). This map matching suppression flag is set to 1 when it is determined that the vehicle has entered the service area or parking area on the highway, as will be described later.
This setting process will be described later with reference to FIG. In this example, the map matching function is suppressed when the map matching suppression flag is 1, and the suppression is released when the map matching suppression flag is 0.

When this flag is 1, the virtual current position (A) is stored as a display candidate point in a predetermined area of the RAM (step 511).

If the map matching inhibition flag is 0 in step 510, then the direction of the line segment from the line segments extracted in step 503 is within the predetermined traveling direction and the predetermined value. Only the line segment is selected (step 504). Further, the vertical line is drawn from the virtual current position (A) for all the extracted n line segments, and the length of the vertical line L (n) is obtained (step 505).

Next, based on the lengths of these perpendiculars, the error cost value ec (n) defined by the following equation is calculated for all the line segments extracted in step 504.

Ec (n) = α × | θcar−θ (n) | + β | L (n) | where θcar is the vehicle direction at the virtual current position (A) and θ (n) is the direction of the line segment. , L (n) is the distance from the virtual current position (A) to the line segment, that is, the length of the perpendicular line, α
And β are weighting factors. The values of these weighting factors are
The deviation between the traveling direction and the direction of the road, or the deviation between the current position and the road may be changed depending on whether the current position is prioritized in selecting the road on the road. For example, when a road whose direction is close to the traveling direction is important, α is increased.

Here, the candidate points will be described. In an initial state such as immediately after the start of the device, the virtual current position (A) is uniquely determined by the user (driver) inputting predetermined information using the switch 14,
And this position exists on the line segment corresponding to the road. However, after the vehicle has traveled, the virtual current position (A) may not exist on the line segment corresponding to the road due to an error of a direction sensor such as a gyro. As a result, for example, as shown in FIG. 6, when a road is branched, that is, when two line segments 63 and 64 appear from a node 62 of the line segment 61 corresponding to the road, which line segment 63 It is often impossible to clarify whether there is a vehicle on the road corresponding to.

Therefore, in such a case, in this embodiment, predetermined points existing on two conceivable line segments are set as candidate points, and their current position, error cost, and accumulation described later. Error cost, etc.
The memory 25 is configured to be stored in a predetermined area of the RAM. In addition, in order to facilitate the description, in the following description, one or more new candidate points will be generated from a single candidate point, unless it is clearly indicated that there are a plurality of candidate points.

Then, the calculated error cost ec
According to (n) and the accumulated error cost es related to the candidate points calculated in the previous process, the accumulated error cost es (n) in this process defined by the following formula is calculated ( Step 506).

Es (n) = (1−k) × es + k × ec (n) Here, k is a weighting coefficient larger than 0 and smaller than 1. This accumulated error cost es (n) represents how much the error cost calculated in the previous process is reflected in the error cost calculated in this process. Further, based on the calculated cumulative error cost es (n), the reliability tr defined by the following formula
st (n) is calculated (step 506).

Trst (n) = 100 / (1 + es (n)) As apparent from the above equation, the accumulated error cost ec
The reliability trst increases as (n) increases.
(N) decreases and approaches 0 (zero). On the other hand, as it becomes smaller, the reliability trst (n) increases, and its value approaches 100.

By performing such processing, n existing in the predetermined range D from the current position A for a certain candidate point
The reliability trst (n) associated with each line segment is obtained. When there are a plurality of candidate points, the reliability trst (m, n) related to n line segments existing in the predetermined range D from each candidate point Cm may be calculated.

Then, based on the calculated reliability trst (n), the point advanced from a certain candidate point along the corresponding line segment by the length corresponding to the distance R traveled by the vehicle is
A new candidate point C (n) is set (step 507). Therefore, when the number of line segments existing in a predetermined range D from the current position A for a certain candidate point and the difference between the azimuth and the vehicle azimuth is a predetermined value or less is n, n A new candidate point C (n) will be generated.

Further, the new candidate points C (n) are sorted according to the value of the reliability trst (n) corresponding to each of the new candidate points C (n) (step 508),
The candidate point C (i) having the highest reliability value is used as a display candidate point, that is, a candidate point for displaying on the display 17, and its position, accumulated error cost, reliability, etc. are stored in the RAM of the memory 25. Of the candidate points other than the display candidate points, the accumulated error cost, the reliability, etc. are also stored in a predetermined area of the RAM (step 509).

For example, as shown in FIG. 6, it is assumed that the current position A is represented by the position indicated by the point 63 with respect to a certain candidate point 62 existing on the line segment 61. In such a case, the line segments 64 and 6 which are present in the predetermined range D from the current position A and in which the difference between the direction and the vehicle direction is less than or equal to the predetermined value.
5, the distances L (1) and L (2) from the current position A to the line segments 64 and 65 are calculated, and the calculated distances and the angles θ (1) and θ (of the line segments 64 and 65 are calculated. 2) and the related error cost based on the vehicle direction θcar, etc.
Calculate the accumulated error cost and reliability. Further, based on the traveling distance R of the vehicle obtained in step 405 of FIG. 3, a length corresponding to the traveling distance R from a certain candidate point 62 along the line segments 61 and 64 or the line segments 61 and 65. The position advanced by only is calculated, and the points corresponding to this position are set as candidate points 66 and 67, respectively. Of the candidate points 66 and 67 thus obtained, the highest reliability trs
A display candidate point has a large value of t.

Further, as shown in FIG. 7, with respect to the candidate point 66 on the line segment 64, the new current position A is represented at the position indicated by the point 71, while the candidate on the line segment 65 is selected. Point 67
On the other hand, it is assumed that the new current position A ′ is represented by the position indicated by the point 72. In this case, the line segments 73 and 74 existing in the predetermined range D from the current position A and having a difference between the azimuth and the vehicle direction of a predetermined value or less are taken out, and the new range A ′ from the new current position A ′ is extracted. A line segment 75 existing in D and having a difference between the heading and the vehicle heading equal to or less than a predetermined value is extracted. Then, the distances L1 (1) and L1 (2) from the current position A to the line segments 73 and 74 are calculated, and the distance L2 from the current position A ′ to the line segment 73 is calculated.
Calculate (1). Furthermore, the distance calculated in relation to the current position A, the angles θ1 (1) and θ of the line segments 73 and 74
1 (2) and the vehicle heading θcar, the related error cost, accumulated error cost and reliability are calculated, and the distance calculated in relation to the current position A ′ and the angle θ2 (1 of the line segment 73 are calculated. ) And the vehicle direction θcar, etc., and the associated error cost, accumulated error cost, and reliability are calculated.

Further, based on the traveling distance R of the vehicle obtained in step 405 of FIG.
4 and 73, or along line segments 64 and 74,
Alternatively, the position advanced from the candidate point 67 along the line segments 65 and 67 by the length corresponding to the traveling distance R of the vehicle is calculated, and the points corresponding to this position are set as new candidate points, respectively. . FIG. 8 shows the candidate points 81 to 83 newly obtained in this way.

As in the example described with reference to FIG. 6, the highest reliability trst of the candidate points 81 to 83.
The one with a large value of becomes a display candidate point. In addition, in the present embodiment, the data related to the 14 candidate points can be stored. Therefore, step 5 of FIG.
In the case where 15 or more candidate points are calculated in 09, among these, 1 is set in descending order of the reliability trst.
Various data related to the four candidate points will be stored in a predetermined area of the RAM of the memory 25.

By the way, in the above-mentioned step 503,
A preset distance D centered on the virtual current position (A)
Although the road data (line segment) inside is taken out, this distance D may be a value determined based on the value of the reliability trst of the candidate point calculated in step 509 performed last time.

The reason for obtaining the search range based on the reliability is that the reliability of the accuracy of the current position obtained last time is considered to be low when the reliability is low, so a wider range is searched. This is because searching for a road is more suitable for obtaining the correct current position.

Further, there may be a case where there is no line segment within the predetermined range D from the current position A for a certain candidate point such that the difference between the direction and the heading of the vehicle is a predetermined value or less. In this case, the current position A is the next candidate point calculated from a certain candidate point. On the other hand, in other states, that is, within the predetermined range D from the current position A for a certain candidate point, there is a line segment whose difference between the direction and the traveling direction of the vehicle is a predetermined value or less. As a result, a state in which the next candidate point may exist on a specific line segment is called a matching state.

If there is no line segment within the predetermined range D from the current position A in which the difference between that direction and the traveling direction of the vehicle is less than the predetermined value, the error cost ec to be calculated in step 506. (N) is given a constant value that is larger than the value of the error cost obtained in the matching state.

When the processing up to step 509 is executed, candidate points including the display candidate points are generated, and various data related to these are stored in a predetermined area of the RAM of the memory 25.

With the above processing, the display candidate points are obtained in step 511 when the map matching suppression flag is 1 and in step 509 when the map matching flag is 0. Therefore, next, using the display candidate point obtained in step 511 or step 509 and the current position calculated by the GPS receiver 29, a process of finally obtaining the display candidate point representing the current position (step 512). ~ 517) is performed.

In this process, it is first determined whether or not the GPS position adoption inhibition flag GPS_f is 1. The GPS position adoption suppression flag GPS_f is set to 1 when the map matching suppression flag is set to 1 as described later. That is, it is set to 1 when it is determined that the vehicle has entered the service area or parking area on the highway. This setting process will be described later with reference to FIG. In this example, the GPS position adoption suppression flag GPS_f
When 1 is 1, the current position calculated by the GPS receiver 29 is prevented from being adopted as a display candidate point that finally represents the current position. Now, after the GPS position adoption suppression flag GPS_f is set to 1, the vehicle is located at the distance lth.
When running, it is initialized to 0. Steps 513-515
Is a process for this initialization. This is probably because the vehicle entered the service area or parking area on the highway and then returned to the main line of the highway from the service area or parking area after traveling the distance lth. The distance 1th is set to a distance that allows such a determination to be appropriately executed. It should be noted that GPS_l is a parameter which is initialized to 0 when GPS_f is set to 1, as will be described later, and the process of step 513 always causes GPS_f to be set in the vehicle after GPS_f is set to 1. Updated to show mileage.

Here, the map matching suppression flag described above is also reset to 0 by the processing of FIG. 13 which will be described later, when it is considered that the service area or parking area has returned to the main line of the expressway. The distance lth is set so that the GPS flag is reset to 0 after the vehicle has been running for a while after the map matching suppression flag is reset to 0. The reason for doing this will be described later.

Since lth is determined as described above, when GPS_f is 1, a display candidate point is obtained in step 511. Therefore, in step 518, the current position calculated by the GPS receiver 29 is not adopted, and the display candidate point obtained in step 511 is finally selected as the display candidate point representing the current position.

On the other hand, when GPS_f is 0, it means that the display candidate points are obtained in step 509. Therefore, in step 517, it is determined which of the display candidate points obtained in step 509 and the current position calculated by the GPS receiver 29 is the most appropriate display candidate point representing the current position. In this determination, if the deviation between the display candidate point obtained in step 509 and the current position calculated by the GPS receiver 29 is larger than a predetermined distance threshold value, the current position calculated by the GPS receiver 29 is calculated. The position is finally selected as a display candidate representing the current position, and conversely, if the deviation is smaller than a predetermined threshold value, the display candidate point obtained in step 509 is finally displayed representing the current position. A selection is made as a candidate. Here, when the candidate point in the matching state is selected in step 509, the threshold value is set to be larger than that in the other case. The matching candidate point selected as the display candidate point in step 509 can be expected to have higher reliability than the non-matching candidate point selected as the display candidate point in step 509. By making it larger, it becomes easier to be finally selected as a display candidate point representing the current position.

In this way, when the display candidate point representing the current position is finally selected, the process proceeds to step 519 to finally output the data such as the coordinates of the display candidate point representing the current position, This process ends.

The display candidate points finally output at 519 are displayed on the screen of the display 17 by the processing based on the flowchart shown in FIG.

This process is a routine of the microprocessor 24 which is activated and executed every one second.

First, it is determined whether the switch 14 is instructed to change the scale of the map by pressing the switch 14 by looking at the contents of the parallel I / O 21 (step 1001). If it is pressed (Yes in step 1001), a predetermined scale flag is set correspondingly (step 100).
2).

Next, the data indicating the position and orientation of the display candidate point obtained by executing the process of FIG. 5 is read from a predetermined area of the RAM of the memory 25 (step 1003) and switched in step 1002. The map of the scale according to the content of the scale flag is displayed on the display 17,
For example, it is displayed in the state as shown in FIG. 2 (step 1
004).

Then, the position and orientation of the display candidate point are displayed by using the arrow symbol "↑", for example, as shown in FIG. 2 described above, superposed on the map (step 100).
5). Finally, the north mark indicating north and the distance mark corresponding to the reduced scale are displayed so as to be superimposed on them as shown in FIG. 2 (step 1006).

In the present embodiment, the vehicle position and direction are indicated by using the arrow symbols as described above, but the display form of the vehicle position and direction indicates that the position and the traveling direction are
The form may be arbitrary as long as the display state is clearly shown. The same applies to the north mark and the like.

As described above, in this embodiment, the map matching suppression flag is set to 1 and the GPS
By setting the position non-adoption flag GPS_f to 1, the position matched on the road by the map matching process or the current position calculated by the GPS receiver 29 is finally calculated as the position indicating the current position. That is being deterred.

Here, as described above, the pre-matching suppression flag and the GPS position non-adoption flag GPS_f are set to 1 in the service area (SA) or parking area (PA) of the highway.

The processing for that will be described below.

First, when the apparatus is started, the traveling distance L after the area determination processing, the area determination flag flag, the map matching suppression flag are set to 0, the GPS position non-adoption flag GP is set.
Initialize various parameters such as S_f.

Then, the processing shown in FIG. 10 is executed to control the setting and resetting of the map matching suppression flag and the setting of the GPS position non-adoption flag GPS_f.

The process shown in FIG. 10 is executed after the completion of the process for calculating the current position shown in FIG.

As shown in the figure, in this processing, first, the distance L which is the distance traveled after the area determination processing described later is performed.
It is checked whether is 0 or less (1101). When L is 0, the area determination flag fla is set to enable the area determination.
g is set to 0 (step 1103). If L is not 0, the value of L is updated (decremented in this example) (step 1102).

Then, it is checked whether or not the area determination flag flag is 0 (step 1104). If it is 0, it is checked whether or not the road currently traveling is a highway based on the above-mentioned highway flag (step 1105). If not on the highway, step 1108
Go to. If it is on an expressway, the next step 1106
Then, it is checked whether or not there is a branch point within a predetermined distance ahead of the road currently underway based on the road data and the current position (step 1106). If there is no branch point, the process proceeds to step 1108. If there is a branch point, there is a possibility of entering the service area or the parking area, so in the next step 1107, an area determination process is performed to determine whether or not the service station or the parking area is entered. This detailed processing will be described later with reference to FIG.

If the flag is not 0 in step 1104, these steps 1105-1107 are not executed and the process jumps to step 1108. The setting of the flag is performed in the step 1103 and the area determination processing of FIG. 12 described later, except for the initialization processing.

In step 1108, it is checked whether or not the area determination flag flag is 0, and if it is 0, this processing is ended as it is, and if it is not 0, area processing described later is executed in step 1109 and this processing is ended. To do.

Next, FIG. 11 shows an example of a specific processing procedure of the area determination processing in step 1107.

In this process, first, after confirming the branch point, one road connected to the branch point is traced forward by road data search (1201) to check whether there is a new branch point (1202). . If there is no new branch point,
The road is examined until the state continues for 500 m or more (steps 1209 and 1201). If the branch point is still not found, this process ends. If a branch point is found in the meantime, in step 1203, another road connected to the preceding first branch point is searched. Therefore, it is determined whether or not there is a branch point ahead of this road in steps 1201 and 12 as well.
02, 1209, and step 120
3, 1204, 1205. If there is no branch point, the process ends. If there is a branch point, it is checked whether this branch point is the same as the branch point detected in step 1202 last time (1206). The fact that both branch points are the same means that, after passing through the first branch point, the two roads split at this branch point have merged again within about 500 m. This is considered to indicate the existence of a service area or parking area on the highway. If they are not the same, this process is terminated. If they are the same, the next step 12
Proceed to 07.

When it is determined in step 1206 that the same branch point is found, in the next step 1207, the traveling distance L after this area determination processing is set to 1000 m. As described above, the value of this distance L is obtained in step 11 of FIG.
In 02, the new traveling distance is subtracted and is used in the area processing of FIG. Then, step 12
In 08, the flag is set to 1 and this processing is ended. By setting this flag to 1, after entering SA and PA, the area determination process (step 11 in FIG. 11) is performed again.
Avoid performing 07).

Next, referring to FIG. 12, an example of a specific processing procedure of the area processing in step 1109 will be described.

First, in step 1301, it is checked whether or not the distance L has become 0 or less.
This is 0 or less (No in step 1301) means that the mileage after the area determination is 1000
It means that it became m or more. When step 1302 is first entered after setting the distance L in step 1207, naturally L> 0, and the next step 1302
Then, it is checked whether or not the vehicle has turned based on the data of the traveling direction. To check whether the vehicle has turned,
This is because even if the presence of the service area or the parking area is confirmed in step 1206 of FIG. 12, it is unclear whether the road selected by the vehicle at the branch point is the road on the area side. Normally, a vehicle normally turns to enter such an area, and therefore, by detecting this, entry into the area can be detected. Therefore, only when such turning is detected, it is determined that the vehicle enters SA or PS. Such a turn can be detected by a change in the traveling azimuth by a predetermined angle or more (for example, the integrated amount of the azimuth change of several points in the past exceeds a predetermined position). Step 13
If the determination result in 02 is No, this processing ends.

If the result of the determination in step 1302 is Yes, then in the next step 1303, the execution of the subsequent map matching and the GPS receiver 29 from being finally calculated as the current position representing the current position are suppressed. Therefore, the map matching suppression flag and the GPS position non-adoption flag are set to 1. In addition, GPS_l is initialized to 0. As a result, the map matching process in steps 504 to 509 of FIG. 4 is skipped, and the position calculated by the GPS receiver 29 in step 515 of FIG. 4 is finally calculated as a display candidate point representing the current position. Will be suppressed, and the current position (A) will be displayed on the screen as it is. When the present position (A) is calculated, the previous present position (A) serves as a reference for the calculation. As a result, the inconvenience caused by the map matching as described above is eliminated. After step 1303, this process ends.

Next, when the distance L becomes 0 or negative in step 1301, this causes the vehicle to exit SA or PA, or after the branch point, the vehicle does not turn 10
Since it is estimated that the vehicle has traveled 100 km, the map matching suppression flag is set to 0 and the distance L is reset to 0 (step 1304). As a result, the map matching function comes to work again.

However, as described above, the above-mentioned lth
By this function, the GPS position adoption flag G at this point
PS_f has not been reset to 0 yet.

This is due to the following reason.

That is, immediately after the map matching suppression flag is reset to 0, the display candidate point may not always be immediately obtained at the correct position by the map matching process. However, even in such a case, there is a high possibility that the display candidate point will be obtained at the correct position by the above-described map matching process while the map matching is repeated several times. Therefore, after the map matching is started, the present position calculated by the GPS receiver 29 is calculated as a display candidate point representing the final present position, and after the map matching is started, the map matching process is performed.
We expect that the display candidate points will be found at the correct positions.

The various numerical values in the above description, for example, 20 m, 500 m, 1000 m, etc. do not limit the present invention. Further, the processing of FIGS. 4 and 11 is always performed every 20 m, but, for example, step 1
After confirming the branch point in 106 to step 1304, it is possible to perform the operation every shorter distance (for example, 10 m) to increase the frequency of detection of turning and updating of the current position (A) in step 1302. .

[0092]

As described above, according to the present invention, in a hybrid current position calculating apparatus that uses map matching and GPS together, even when a vehicle enters a service area or a parking area of an expressway, It is possible to provide a current position calculation device that does not erroneously calculate the current position of.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a display example of a map and a current position according to the embodiment.

FIG. 3 is a flowchart showing a process of calculating a traveling direction and a traveling distance of a vehicle in the embodiment.

FIG. 4 is a flowchart showing a process of calculating the current position of the vehicle in the embodiment.

FIG. 5 is a diagram for explaining an example of road data according to the embodiment.

FIG. 6 is a diagram for explaining a line segment corresponding to a road, a virtual current position, and a candidate point.

FIG. 7 is a diagram for explaining a line segment corresponding to a road, a virtual current position, and a candidate point.

FIG. 8 is a diagram for explaining a line segment corresponding to a road, a virtual current position, and a candidate point.

FIG. 9 is a flowchart showing a display process in the embodiment.

FIG. 10 is a flowchart of processing related to a service area and a parking area in the embodiment.

FIG. 11 is a flowchart showing a detailed procedure of the area determination processing shown in FIG.

12 is a flowchart showing a detailed procedure of the area processing shown in FIG.

[Explanation of symbols]

 10 Current Position Calculation Device 11 Angular Velocity Sensor 12 Direction Sensor 13 Vehicle Speed Sensor 14 Switch 15 CD-ROM 16 CD-ROM Read Driver 17 Display 18 Controller

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] September 6, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

[0014] However, in the map coverage area or in a parking area was controlled matching means to estimate a current position independently of the virtual current position from the signal Yoriyukido, current location using Satellite current position calculation means has calculated However, it becomes easy to determine the final current position.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

[0019] In addition, the user and the display 17 to display the mark or the like that shows the map and the current position around the current position, a command switching the scale of the map to be displayed on the display 17 The
Switch 14 accepted from ( driver), CD-ROM 15 for storing digital map data, and its CD
A driver 16 for reading map data from the ROM 15. Further, the controller 18 for controlling the operation of each peripheral device described above is provided. In the present embodiment, the digital map data described above includes road data composed of coordinates indicating the ends of a plurality of line segments,
Alternatively, it includes road width data indicating the road width of the road, a highway flag indicating whether the road is a highway or a general road, and the like.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

As described above, in this embodiment, the road data is approximated by a plurality of line segments 51 to 56 connecting the two points as shown in FIG.
The one represented by the coordinates of the start point and the end point is used. For example, the line segment 53 has its starting point (x3, y3)
And the end point (x4, y4).

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

Ec (n) = α × | θcar−θ (n) | + β × | L (n) | where θcar is the vehicle direction at the virtual current position (A), and θ (n) is a line segment. The azimuth, L (n), is the distance from the virtual current position (A) to the line segment, that is, the length of the perpendicular line, α
And β are weighting factors. The values of these weighting factors are
The deviation between the traveling direction and the direction of the road, or the deviation between the current position and the road may be changed depending on whether the current position is prioritized in selecting the road on the road. For example, when a road whose direction is close to the traveling direction is important, α is increased.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction content]

Trst (n) = 100 / (1 + es (n)) As apparent from the above equation, the accumulated error cost es
The reliability trst increases as (n) increases.
(N) decreases and approaches 0 (zero). On the other hand, this
The reliability trst (n) becomes
It increases and its value approaches 100.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Change

[Correction content]

Further, as shown in FIG. 7, with respect to the candidate point 66 on the line segment 64, the new current position A is represented at the position indicated by the point 71, while the candidate on the line segment 65 is selected. Point 67
On the other hand, it is assumed that the new current position A ′ is represented by the position indicated by the point 72. In this case, the line segments 73 and 74 existing in the predetermined range D from the current position A and having a difference between the azimuth and the vehicle direction of a predetermined value or less are taken out, and the new range A ′ from the new current position A ′ is extracted. A line segment 75 existing in D and having a difference between the heading and the vehicle heading equal to or less than a predetermined value is extracted. Then, the distances L1 (1) and L1 (2) from the current position A to the line segments 73 and 74 are calculated, and the distance L2 from the current position A ′ to the line segment 75 is calculated.
Calculate (1). Furthermore, the distance calculated in relation to the current position A, the angles θ1 (1) and θ of the line segments 73 and 74
1 (2) and the vehicle direction θcar, the related error cost, accumulated error cost, and reliability are calculated, and the distance calculated in relation to the current position A ′ and the angle θ2 (1 of the line segment 75 are calculated. ) And the vehicle direction θcar, etc., and the associated error cost, accumulated error cost, and reliability are calculated.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Change

[Correction content]

Further, based on the traveling distance R of the vehicle obtained in step 405 of FIG.
4 and 73, or along line segments 64 and 74,
Alternatively, a position advanced from the candidate point 67 along the line segments 65 and 75 by a length corresponding to the mileage R of the vehicle is calculated, and the points corresponding to this position are respectively set as new candidate points. . FIG. 8 shows the candidate points 81, 82 and 83 newly obtained in this way.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Change

[Correction content]

As in the example described with reference to FIG. 6, the highest reliability tr among the candidate points 81, 82 and 83.
A large value of st is a display candidate point. In addition, in the present embodiment, the data related to the 14 candidate points can be stored. Therefore, when 15 or more candidate points are calculated in step 509 of FIG. 4, among these, various data related to 14 candidate points in descending order of the value of the reliability trst are stored in the memory 25.
Will be stored in a predetermined area of the RAM.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0071

[Correction method] Change

[Correction content]

As described above, in this embodiment, the map matching suppression flag is set to 1 and the GPS
By setting the position adoption suppression flag GPS_f to 1, the position matched on the road by the map matching process or the current position calculated by the GPS receiver 29 is finally calculated as the position representing the current position. That is being deterred.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Name of item to be corrected] 0072

[Correction method] Change

[Correction content]

[0072] Here, as described above, map matching suppression flag, GPS position adopted inhibition flag GPS_f
Is set to 1 in the service area (SA) or parking area (PA) of the expressway.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0074

[Correction method] Change

[Correction content]

First, when the apparatus is started, the traveling distance L after the area determination processing, the area determination flag flag, the map matching suppression flag are set to 0, and the GPS position adoption suppression flag G is set.
Initialize various parameters such as PS_f.

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0075

[Correction method] Change

[Correction content]

Then, the processing shown in FIG. 10 is executed to set / reset the map matching inhibition flag and the GPS position.
It controls the setting of the adoption inhibition flag GPS_f.

[Procedure Amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0078

[Correction method] Change

[Correction content]

Then, it is checked whether or not the area determination flag flag is 0 (step 1104). If it is 0, it is checked whether or not the road currently traveling is a highway based on the above-mentioned highway flag (step 1105). If not on the highway, step 1108
Go to. If it is on an expressway, the next step 1106
Then, it is checked whether or not there is a branch point within a predetermined distance ahead of the road currently underway based on the road data and the current position (step 1106). If there is no branch point, the process proceeds to step 1108. If there is a branch point, there is a possibility of entering the service area or the parking area.
Area determination processing is performed to determine whether the vehicle has entered the area or the parking area. This detailed processing will be described later with reference to FIG.

[Procedure Amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0086

[Correction method] Change

[Correction content]

If the result of the determination in step 1302 is Yes, then in the next step 1303, the execution of the subsequent map matching and the GPS receiver 29 from being finally calculated as the current position representing the current position are suppressed. Therefore, the map matching suppression flag and the GPS position adoption suppression flag are set to 1. In addition, GPS_l is initialized to 0.
As a result, the map matching process in steps 504 to 509 of FIG. 4 is skipped, and the position calculated by the GPS receiver 29 in step 515 of FIG. 4 is finally calculated as a display candidate point representing the current position. Will be suppressed, and the current position (A) will be displayed on the screen as it is. When the present position (A) is calculated, the previous present position (A) serves as a reference for the calculation.
As a result, the inconvenience caused by the map matching as described above is eliminated. After step 1303, this process ends.

[Procedure Amendment 15]

[Document name to be amended] Statement

[Correction target item name] 0088

[Correction method] Change

[Correction content]

However, as described above, the above-mentioned lth
By this function, the GPS position adoption suppression flag GPS_f is not yet reset to 0 at this point.

Claims (3)

[Claims] 1. A current position calculating device which is mounted on a vehicle and calculates the current position of the vehicle, comprising: satellite-using current position calculating means for calculating the current position based on radio waves received from satellites; Means for storing map data representing a road map, including road data having data indicating whether it is a road or a highway, a direction detecting means for detecting a traveling direction of the vehicle, and a distance calculating means for calculating a traveling distance of the vehicle. A virtual current position based on the traveling azimuth detected by the azimuth detecting means and the travel distance calculated by the distance calculating means, and the virtual current position and the road data included in the map data. When there is a position on the road whose reliability as the current position is higher than that of the virtual current position as the current position, the position on the road with the highest reliability is compared. Position is estimated as the current position, and if there is no position on the road whose reliability as the current position is higher than the reliability of the virtual current position as the current position, map matching that estimates the virtual current position as the current position Means, the current position estimated by the map matching means, and one of the current position calculated by the satellite-use current position calculation means are selected according to a predetermined criterion, and the current position is determined as the final current position. Determination means, based on the estimated current position and the road data,
The vehicle includes an area determination unit that determines whether the vehicle has entered the service area or the parking area from the main line of the highway and whether the vehicle has returned from the service area or the parking area to the main line, and the predetermined criterion is the When the virtual current position is estimated as the current position by the map matching means,
Compared to other cases, the current position calculated by the satellite use current position calculation means is a criterion determined to be easily determined as the final current position, the map matching means, to the service area or parking area During the period from the entry to the return to the main line, the virtual current position is unconditionally estimated as the current position, and the current position determination means returns to the main line after entering at least the service area or parking area. The current position calculating device is characterized in that the current position estimated by the map matching means is unconditionally determined as a final current position during the period including up to. 2. The area determining means detects a branch point on a highway by a vehicle on the basis of the estimated current position and the road data, and one of the roads at the branch point from the branch point. 2. The vehicle is determined to have entered the area when it is detected that the vehicle will join the other road again within a predetermined distance, and when the vehicle turns after the passage of the branch point. Current position calculator. 3. The area determining means determines that the vehicle has returned to the main line when the traveling distance after entering the service area or the parking area reaches a predetermined distance. 2. The current position calculation device described in 2.