JPH06111196A - Current position display device for moving body - Google Patents

Abstract

PURPOSE:To properly execute the correction of a current position by means of self-navigation by performing a parallel translation to a traveling locus based upon self-navigation to the traveling locus side of a global positioning system(GPS) and then rotating the locus to correct the position. CONSTITUTION:A signal processing part 4 sequentially calculates the current position of a moving body by self-navigation and measures the current position of the moving body by GPS. The processing result of the processing part 4 is sequentially sent and stored to/in a traveling locus storing part 5. When an angle formed by the traveling locus of the moving body based upon self- navigation with the traveling locus based upon GPS exceeds a previously set threshold, the processing part 4 executes the parallel translation of the traveling locus based upon self-navigation so that the current position of the moving body based upon the self-navigation coincides with a position measured by the GPS. Then the traveling locus of the self-navigation is rotated on the traveling locus side of the GPS. Then the current position of the moving body is displayed on a road map displayed on the screen of a display part 8 based upon the position-corrected traveling locus of the self-navigation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current position display device for a mobile body, which detects the current position of the mobile body and displays the current position of the mobile body on a road map previously projected on a screen.

[0002]

2. Description of the Related Art Recently, in order to guide the travel of a moving body such as an automobile, a screen on which a road map of a planned traveling area is displayed in advance while detecting a current position which changes every moment as the moving body moves. A current position display device for a mobile body has been developed which updates and displays the current position of the mobile body on the basis of point information.

As a current position display device for a moving body of this type, the current position on the XY coordinates is detected while the traveling distance and the traveling direction of the moving body are respectively detected by a distance sensor and a direction sensor mounted on the moving body. There is a self-contained navigation that is sequentially obtained by cumulative arithmetic processing.

In this self-contained navigation method, position errors are accumulated and the current position gradually deviates from the road on the map. Therefore, in order to correct the current position, the road pattern on the map and the moving object Performs processing to match the pattern of the running locus obtained by storing and holding the data of the current position, which is sequentially updated as the vehicle runs, and fits the running locus to the road portion where the pattern is matched. The current position of the moving body is corrected by (see JP-A-1-41817).

However, in such a self-contained navigation method, when the vehicle travels off the road over a long distance (including road traveling not on the map), the current position can be corrected by the above-mentioned map matching processing. There is a problem that you can not do it.

Therefore, conventionally, the current position of the moving body can be directly measured and the position error is not accumulated so that the position measurement by the GPS (Global Positioning System) using the artificial satellite is also used together. The self-contained navigation is mainly used to display the current position of the moving body, and as described above, when the self-contained navigation is unsuitable, the GPS is switched to GPS, and the moving body's position is measured based on the position of the moving body measured by the GPS. The current position can be displayed continuously (Japanese Patent Application Laid-Open No. Hei 4-
50718).

Further, conventionally, when GPS and self-contained navigation are used together, GPS is mainly used to measure the current position of a moving body, and when the position cannot be measured by GPS depending on the location. By switching to the self-contained navigation, the current position of the moving body can be continuously displayed (see Japanese Patent Laid-Open No. 61-13709).

[0008]

The problem to be solved is to use the self-contained navigation and GPS together to continuously display the current position of the moving body while appropriately switching between the two depending on the situation. To intentionally degrade the positioning accuracy of GPS due to military problems, etc.
Since (Selective Availability) is introduced, the position accuracy is deteriorated, and the current position of the moving body displayed on the road map is out of alignment with the actual position.

[0009]

According to the present invention, a self-contained navigation system and a GPS system are used in combination, and the current position of the moving body is continuously displayed while appropriately switching the two depending on the situation. The position calculated by the self-contained navigation is used so that the current position is corrected properly by the self-contained navigation while comparing the data of the respective positions obtained by always working the two, instead of letting them perform the calculation. And G
The travel loci are obtained by storing and holding the data of each sampling position in the memory when the measurement position of the moving body by PS is sampled at the same timing, and the latest sampling position P _{0 in} each travel locus is obtained. It is determined whether or not the angle θ ₀ formed by the straight lines connecting the line and the immediately preceding sampling position P ₁ exceeds a preset threshold value, and when the angle θ ₀ exceeds the threshold value, the latest value obtained by self-contained navigation So as to reach the latest sampling position by GPS, the traveling locus by self-contained navigation is translated, and further, the latest sampling position P _{0 on} each traveling locus and a plurality of sampling positions P ₁ , P _2, the angle theta ₀ of the straight line between the respective corresponding connecting ... _and, theta _1, ... seeking average angle θa of its In terms of the position correction by rotating the travel locus by only autonomous navigation average angle θa to travel locus side of GPS,
The current position of the moving body is updated and displayed on the road map displayed on the screen based on the corrected trajectory of the self-contained navigation.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the configuration of a current position display device for a moving body according to the present invention. A rate-type direction sensor 2 that outputs a signal proportional to the amount of change in direction due to traveling of a mobile body, and an antenna AN that emits radio waves emitted from a satellite as a reference point.
By measuring the traveling distance of the moving body by time-integrating the traveling speed detected by the speed sensor 1 and the receiver 3 receiving via T, and by integrating the angular velocity detected by the direction sensor 2 by time. While determining the amount of change in the traveling direction of the moving body, the current position on the XY coordinates for each unit traveled distance of the moving body is sequentially calculated by self-contained navigation, and according to the received radio waves, the current position on the same coordinate is calculated by GPS. A signal processing unit 4 including a microcomputer that measures the current position of the mobile unit and controls the entire device in a centralized manner, and data of the current position of the mobile unit obtained by self-contained navigation and GP.
The data of the current position of the moving body measured by S is sequentially stored, and the traveling locus storage unit 5 that stores and stores the data as the finite continuous position information of the moving body, and the information of a plurality of road maps are respectively stored in advance. Map information storage medium 6 stored with position data on the XY coordinates of the road
And a storage medium reproducing unit 7 for selectively reading road map information from the storage medium 6, and displaying a predetermined road map on the screen based on the read map information.
A display unit 8 for displaying the current position of the moving body on the road map displayed on the screen, along with the traveling locus and the traveling direction of the moving body at the current position as necessary, and the signal according to the traveling of the moving body. The operation command is given to the processing unit 4, the map to be displayed on the display unit 8 is designated and the starting point of the moving body is set on the displayed map, and the display command such as the traveling locus is selectively selected. Giving and changing the direction of the displayed map and traveling locus, shifting the display position, partially enlarging the map and traveling locus,
The operation unit 9 is capable of appropriately changing the setting of the display form such as selection of the display scale factor.

Here, the method for calculating the current position of the moving body by the self-contained navigation is exactly the same as the conventional method, and a known method for measuring the position by GPS is applied as it is.

According to the present invention having such a configuration, basically, the present position of the moving body obtained by self-contained navigation is displayed on the screen.

That is, the map read from the map information storage medium 6 is displayed on the screen of the display unit 8 and
The current position on the XY coordinates is obtained by calculation every moment according to the scale of the map set in advance by the signal processing unit 4 according to the traveling of the mobile body from the starting point set on the map, The calculation results are sequentially sent to the traveling locus storage unit 5 and their stored contents are updated, and the stored contents are constantly read and sent to the display unit 8.

As a result, the display unit 8 displays, for example, in FIG.
As shown in FIG. 3, a display mark M1 indicating the current position of the moving body on the map displayed on the screen, a display mark M2 indicating the traveling direction of the moving body at the current position, and a starting point S.
Display mark M3 of the running track from T to the current position
Is simulated and displayed according to the running state of the moving body.

In the present position display of the moving body by such a self-contained navigation, as shown in FIG. 3, the present position and the traveling locus gradually deviate from the road on the map as the traveling of the moving body progresses due to the accumulated error mentioned above. Eventually, it will not be possible to determine where on the map the vehicle is currently traveling.

Therefore, in the present invention, in the signal processing unit 4, when the current position of the moving body and the traveling locus up to that point deviate from the road on the map, as described below, the pattern of each road in the vicinity and If the similarity with the pattern of the traveling locus of the moving body is equal to or more than a preset value, both patterns are matched, the matched road is regarded as the currently running road, and The running locus is adjusted to correct the current position of the moving body and the display position of the running locus.

At this time, when matching the pattern of the traveling locus and the pattern of the road, for example, a road along the traveling locus of the moving body or a road within a certain distance range from the current position of the moving body, Roads having a certain correlation with the traveling locus or the current position are extracted as candidates for roads to be matched to reduce the burden of the matching process.

The extraction of the candidate roads is specifically performed as follows.

First, the estimated current position of the moving body is set on the road on which the vehicle is currently traveling and on all roads branched from the road according to the fixed traveling distance of the moving body.

At this time, as shown in FIG. 4, if there is no branch road within a certain distance L from the set point of the estimated current position x'in the previous time, as the road currently running, according to the running of the moving body. The estimated current position x is set at a position advanced by the certain distance L.

Further, as shown in FIG. 5, if there are branch roads within the fixed distance L, the estimated current positions x1, x2 and x3 are set to all of the branch roads, respectively. Where l1
There is a relationship of + l2 = l1 + l3 = l1 + l4 = L.

The estimated current position is set according to the position data of the road in the map displayed on the screen of the display unit 8 each time it is detected that the moving body has traveled a certain distance L. It is automatically performed under the control of the signal processing unit 4. The estimated current position may be set independently of the travel distance of the moving body, and the estimated current position may be sequentially set every time a predetermined time elapses as the moving body travels. In addition, depending on the traveling situation of the moving body,
It is also possible to make the setting interval of the estimated current position variable. Each road is segmented into lines, and position data on the XY coordinates of each line segment is stored in the map information storage medium 6.

Next, whether the distance between the estimated current position set as described above and the current position of the moving body calculated at that time and displayed off the road is within a predetermined allowable range. It is determined whether or not the estimated current position within the range is selected, and only the road where the selected estimated current position exists is a candidate for matching.

Now, for example, in the relationship of FIG. 6, when the distance between the estimated current position x (x1, x2, x3) and the current position P is D (D1, D2, D3), the following equation D ≤αL + M (1) Select an estimated current position that satisfies the relationship (1).

Here, M is a preset allowable range, for example, set to about 50 m. a is a coefficient relating to position accuracy when the traveling distance of the moving body is used as a parameter, and is set to, for example, about 5%. Also, as L,
It is set to about 100m.

At this time, the estimated current position set on the road having a direction within a certain allowable angular difference with respect to the traveling direction of the current position P of the moving body is selected. It is also possible.

However, in the relationship of FIG. 6, if the value of M is set to be relatively small, only x2 is selected as the estimated current position satisfying the condition of the expression (1), and the estimated current position is selected. The road where x2 exists is a candidate road that is the target of the matching process.

Therefore, even if there are many roads near the current position deviating from the road, it is necessary to select the minimum number of road candidates that have a high probability of being matched as the target of the matching process. Therefore, the burden of the matching process can be effectively reduced.

A known method is widely applied as a method for matching the pattern of the traveling locus and the pattern of the candidate road.

In such a current position display device for a moving body, particularly in the present invention, the current position of the moving body by the self-contained navigation and the position measured by GPS are greatly separated (for example, 1 km or more), or the above-mentioned estimation is performed. If the current position cannot be found, or if the pattern of the traveling path and the pattern of the candidate road cannot be matched, the signal processing unit 4 corrects the current position obtained by the self-contained navigation as follows. I'm trying to get it done.

First, as shown in FIG. 7, the traveling locus storage unit 5 stores data at each sampling position when the current position of the moving body obtained by self-contained navigation and the position measured by GPS are sampled at the same timing. The traveling loci LP1 and LP2 are obtained by holding them, and then the straight line connecting the latest sampling position P ₀₁ on the traveling locus LP1 and the sampling position P ₁₁ immediately before it and the latest sampling position on the traveling locus LP2. seeking the angle theta ₀ the arithmetic processing between the straight line connecting the P ₀₂ and the sampling position P ₁₂ of the immediately preceding or exceeds the sought angle theta ₀ is preset threshold (e.g., 6 °) Determine whether or not.

When the threshold value is exceeded,
As shown in FIG. 8, the latest sampling position P ₀₁ by self-contained navigation is the latest sampling position P by GPS.
_The traveling locus LP1 by the self-contained navigation is translated so as to come to ₀₂ .

Next, as shown in FIG. 9, the latest sampling positions (P ₀₁ , P ₀₂ ) on the respective traveling loci LP1, LP2 and, for example, four sampling positions (P ₁₁ , P ₁₂ ) and (P ₁₂ ) before that (P ₁₁ ) are obtained. ₂₁ ,
P ₂₂ ), (P ₃₁ , P ₃₂ ), and (P ₄₁ , P ₄₂ ), the angles θ ₀ , θ ₁ , θ ₂ formed by the corresponding straight lines.
The average angle θa of θ ₃ is calculated and the traveling locus LP1 by self-contained navigation is rotated toward the traveling locus LP2 of GPS by the average angle θa.

Then, the current position of the moving body is displayed on the road map projected on the screen based on the traveling locus LP1 by the self-contained navigation whose position is corrected by the rotation.

The latest sampling position P on the traveling locus LP1 is replaced with a means for determining whether the angle θ ₀ has exceeded a preset threshold value.
It is also possible to employ a means for determining whether or not the distance between ₀₁ and the latest sampling position P ₀₂ on the traveling locus LP2 exceeds a preset threshold value.

In the present invention, when the signal processing unit 4 displays the latest sampling position P _{01 on} the traveling locus LP1 by self-contained navigation, that is, the current position, the traveling direction of the moving body detected at that position, The displayed traveling direction is corrected according to the rotation angle θa of the traveling locus LP1.

Further, according to the present invention, as shown in FIG. 10, when the travel locus LP1 by the self-contained navigation whose position is corrected as described above is not on the road of the map, in the signal processing unit 4, The position-corrected pattern of the traveling locus LP1 based on the self-contained navigation is matched with the pattern of the road portion on the road map, and the traveling locus LP1 is matched to the matched road portion.

The sampling at each position is performed by, for example,
The position is measured by GPS every time the moving body travels 500 m, and the data of the measured position is stored in the traveling locus storage unit 5.
In addition to storing and holding the data, the position is calculated by the self-contained navigation at that timing, and the data of the calculated position is stored and held in the traveling locus storage unit 5.

Alternatively, in order to improve the accuracy of the position obtained by the self-contained navigation, the position is calculated at a traveling interval of several tens of meters and the data of each sampling position is temporarily stored and retained in the traveling locus storage unit 5. And then GP
You may make it resample the position data calculated | required by the self-contained navigation at the timing of the position measurement by S.

When the GPS position measurement becomes impossible depending on the place or the measurement accuracy suddenly decreases, a process is performed so that sampling is not performed at that time.

As the traveling loci LP1 and LP2,
When the locus exceeds a preset maximum length due to the traveling of the moving body and a new sampling position added thereto, the data of the old sampling position is erased accordingly, and the maximum actual length is always 4 km, for example.
It is set to be about.

FIG. 11 shows an example of the flow of processing according to the present invention.

Here, as shown in process A, if the direction sensor 2 has a drift or a zero offset error when the current position of the moving body is obtained by the self-contained navigation, the position error accumulates as the running locus becomes longer. Since the traveling locus is confused, the maximum locus length Lmax is set according to whether or not the direction sensor 2 is in a stable state at the time of rising or the vehicle is stopped within a fixed time and the zero offset correction of the direction sensor 2 is performed. La, Lb, and Lc are set in three stages. For example, when the direction sensor is in the stable state and the zero point offset correction is performed, La = 4 Km is set, and when the direction sensor is in the stable state but the zero point offset correction is not performed, Lb = 2 Km is set. When the direction sensor is not in a stable state and the zero point offset correction is not performed, Lc = 1 Km is set.

[0044]

The present invention's current position display device of the present invention is a combination of a self-contained navigation system and a GPS system, and one of them has a problem in displaying the current position of the mobile device. At the same time, instead of switching to the other and continuously displaying the current position of the moving body, both of them are always operated after allowing the accumulated error of the position obtained by self-contained navigation and the deterioration of the accuracy of the measured position by GPS. This makes it possible to optimally correct the position of the traveling locus by self-contained navigation while comparing the respective traveling loci obtained.

Then, it becomes possible to accurately perform the map matching processing for matching the traveling locus with the road portion on the map based on the traveling locus by the self-contained navigation in which the position is corrected. It becomes possible to display the current position of the moving body at an accurate position.

Further, according to the present invention, when the traveling direction of the moving body is displayed at the current position obtained by the self-contained navigation, when the position of the traveling locus is corrected by the self-contained navigation, the direction at the current position is displayed. It is possible to appropriately correct the traveling direction of the moving body detected by the sensor 2 at the same time.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a display screen in the embodiment.

FIG. 3 is a diagram showing a state in which a traveling locus of a mobile body by the self-contained navigation is displayed off the road on the map.

FIG. 4 is a diagram showing a state in which an estimated current position is set on a road of a map for each constant traveling distance of a mobile body.

FIG. 5 is a diagram showing a state in which an estimated current position is set on a road having a branch road on a map for each constant traveling distance of a mobile body.

FIG. 6 is a diagram showing a relationship between a current position of a moving body that has deviated from the road and an estimated current position set on the road.

FIG. 7 is a diagram showing a relationship between a traveling locus of self-contained navigation and a traveling locus of GPS by sampling at the same timing.

[Figure 8] GP is the latest sampling position for self-contained navigation
It is a figure which shows the state which translated the traveling locus by self-contained navigation so that it may come to the newest sampling position by S.

FIG. 9 is a diagram showing angles formed by corresponding straight lines connecting a latest sampling position and four sampling positions before that on each traveling locus.

FIG. 10 is a diagram showing a traveling locus according to the self-contained navigation in which the position is corrected according to the present invention.

FIG. 11 is a diagram showing an example of a flow of processing according to the present invention.

[Explanation of symbols]

1 speed sensor 2 direction sensor 3 receiver 4 signal processing unit 5 traveling locus storage unit 6 map information storage medium 7 storage medium reproducing unit 8 display unit 9 operation unit LP1 traveling locus by self-contained navigation LP2 traveling locus by GPS P ₀₁ self-contained navigation The latest sampling position in the running track P ₀₂ The latest sampling position in the running track of GPS

Claims (3)

[Claims] 1. A moving body position calculating means by self-contained navigation, which calculates the position of a moving body on a two-dimensional coordinate by sequential calculation while detecting the traveling distance and traveling direction of the moving body, and movement by GPS. The body position measuring means and the latest sampling position P in the running locus obtained by storing and holding the data of each sampling position when the calculated position and the measured position are sampled at the same timing. Angle θ formed by straight lines connecting ₀ and the immediately preceding sampling position P _1
A means for determining whether ₀ has exceeded a preset threshold value, and when the threshold value is exceeded, the latest sampling position obtained by self-contained navigation is at the latest sampling position by GPS, An angle θ formed between the means for translating the traveling locus by self-contained navigation and the corresponding straight lines connecting the latest sampling position P _{0 on} each traveling locus and a plurality of sampling positions P ₁ , P ₂ , ... Before that. A means for obtaining an average angle θa of ₀ , θ ₁ , ..., A means for rotating the traveling locus by the self-contained navigation to the traveling locus side of GPS by the average angle θa, and a position correction, and a traveling by the position-corrected self-contained navigation. A current position display device for a mobile body, which is configured to update and display a current position of the mobile body on a road map displayed on a screen based on a trajectory. 2. A means for displaying the traveling direction of the moving body detected at the latest sampling position in the self-contained navigation trajectory, and an average for rotating the displayed traveling direction by the self-contained navigation trajectory. The present position display device for a moving body according to the above-mentioned item 1, wherein the correction means is provided according to the angle θa. 3. A means for matching a traveling locus pattern of a position-corrected self-contained navigation with a pattern of a road portion on a road map, and fitting the traveling locus of the self-contained navigation to the matched road portion. The present position display device for a mobile body according to the above item 1 is characterized in that: