CA2053502C - Apparatus for displaying a travel position - Google Patents
Apparatus for displaying a travel positionInfo
- Publication number
- CA2053502C CA2053502C CA002053502A CA2053502A CA2053502C CA 2053502 C CA2053502 C CA 2053502C CA 002053502 A CA002053502 A CA 002053502A CA 2053502 A CA2053502 A CA 2053502A CA 2053502 C CA2053502 C CA 2053502C
- Authority
- CA
- Canada
- Prior art keywords
- road
- pattern
- moving body
- travel
- class
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
- G01C21/26—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 specially adapted for navigation in a road network
- G01C21/28—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 specially adapted for navigation in a road network with correlation of data from several navigational instruments
- G01C21/30—Map- or contour-matching
Abstract
Disclosed is an apparatus for displaying a travel position, which, in carrying out steps of calculating X- and Y-coordinates of a current position of the moving body; renewably presenting said current position on a road map indicated on a display screen; matching between a travel trace pattern formed by subsequent current positions and each road pattern on the road map; and putting the travel trace on the mated road pattern for correction of the current position of the moving body deviated from the road on the map, can determine what class of the road the moving body is running on, e.g. mountain road, superhighway or other ordinary road, and also can change the pattern matching condition to be adapted for the class of the road.
Description
-2~53~0Z
Detailed Description of the Invention Technical ScoPe The present invention relates to an apparatus for displayin8 a travel position, which is capable of indicating a current position of a movins body on a road ~ap presented on a screen.
Prior Art Recently, in attempt to guide a moving body, e.g. an autbmobile, an apparatus for displaying a current position of moving body has been developed, in which the current position of the automobile is sequentially estimated in 2ns3so~
data may include an increased amount of errors in defining its meandering portion having a series of sharply turning courses.
Consequently, when a car travelling along a mountain road, it is much difficult to make the car travel trace match with the road patterns obtained on the basis of digitally processed data and displayed on the screen.
Summary of the Invention In view of the foregoing, the present invention was made to provide an apparatus for displaying a current position of a moving body, which, in case the moving body departs from all the roads indicated on the road map screen, can accurately correct its current position on the screen by optimally performing an adaptive pattern matching between the travel trace and the pattern of a road where-along the moving body travelling, in due consideration of an accuracy of the road map based on the digitized data of the road depending upon its category, e.g., mountain road, superhighway and other ordinary road.
The present invention provides an apparatus for displaying a travel position which is capable of recognizing the class of a roadway whereon the moving body now is running and selecting pattern matching conditions including various kinds of parameters and threshold values in accordance with the recognized class of the road.
In accordance with this invention, apparatus for displaying a travel position comprises: (a) means for detecting a running distance travelled and a running direction of a moving body; (b) means for calculating X-and Y- coordinates of a current position of said moving body; (c) means for renewably presenting, on a display screen, the current position of said moving body on a road A
o ~
map read out from a road map storage medium; (d) means for accumulating data, in a memory device, on subsequent current positions of said moving body to form data on a travel trace; (e) means for matching between a travel trace pattern of said moving body and a selected road pattern by means of a given algorithm; (f) means for putting the travel trace on the road pattern for correcting the current position of said moving body deviated from the road on the map; (g) means for determining what class of road the moving body is running on by measuring a number of curves per unit distance; and (h) means for changing a pattern matching condition, including parameters and thresholds usable in the algorithm according to the result of a road class determination.
By another aspect the invention provides a machine-implemented method for displaying a travel position, which includes the steps of: (a) detecting a running distance travelled and a changing direction of a moving body; (b) calculating X- and Y- coordinates of a current position of the moving body; (c) renewably presenting, on a display screen, the current position of the moving body on a road map read out from a road map storage medium; (d) accumulating data, in a memory device, on subsequent current positions of said moving body to form data on a travel trace; (e) matching between a travel trace pattern of the moving body and a selected road pattern by means of a given algorithm; (f) putting the travel trace on the road pattern for correcting the current position of said moving body deviated from the road on the map; (g) determining what class of road the moving body is running on by measuring a number of curves per unit distance; and (h) changing a pattern matching condition, including parameters and thresholds usable in the algorithm according to the result of a road class determination.
2 ~
Brief Description of Drawings Fig. 1 is a block diagram showing a structure of an apparatus for displaying a current position of a moving body according to the present invention.
Fig. 2 shows an example of a road map image with a series of dots representing sequential current car positions appearing on a screen of the travel position displaying apparatus shown in Fig. 1.
Fig. 3 shows an another road map image having sequential current car positions departing from the road on the road map.
Figs. 4(a) and 4(b) show how presumed current car positions are put on a road and road branches for each increment of running distance, respectively.
Figs. 5 shows how the last estimated car position is related to corresponding presumed current car positions on the road map.
Fig. 6 shows how a road pattern to be nominated for pattern matching is formed.
Fig. 7(a) shows how a travel trace approximation is made by using straight increments of equal length.
Fig. 7(b) shows how a selected road pattern approximation is made by using straight increments of equal length.
Fig. 8 shows how a travel trace and a selected road pattern are matched to each other.
Fig. 9 shows a discrepancy between a travel trace and a road pattern when they are laid over each other in pattern matching process.
Fig. 10 shows an equivalently illustrated discrepancy between a travel trace and a selected road pattern when they are laid over each other in pattern matching process.
Fig. 11 is a flow chart showing a procedure for recognizing the road classification.
2 ~
Referring now to the drawings, a preferred embodiment of the present invention will be described in detail as follows:
It will be observed from Fig. l that a travel position displaying apparatus according to the present invention comprises: a speed sensor l for detecting a car's running speed; a direction sensor 2 which is capable of detecting any variation in angular speed in the yaw direction and generating a signal proportional to a change in direction of the car running; a signal processing unit 3 composed of a micro-computer which is capable of controlling the entire system, determining the running distance by multiplying the running speed measured by the speed sensor l by the time elapsed, determining a change in the running direction of - 5a -2053~Q2 micro-computer which is capable of controlling the entire system, determining the runnins distance by multiplyin8 the running speed measured by the speed sensor 1 by the time elapsed, determining a change in tlle running direction of the car by multiplying the angular speed detected by the direction sensor 2 by the time elapsed, and conducting a cumulative algorithmic operation of vectors to determine current car position in terms of X- and Y-coordinates for each unit running distance; a travel trace storage unit 4 for sequentially storing the X- and Y-coordinates of the current car positions as a finite continuous data set; a road map storage medium 5 for storing a plurality of road maps; a storage medium reading unit 6 for selectively reading different road maps; a display unit 7 for presenting a selected road map and the travel trace in terms of sequential current car positions and its runnin8 directions on an associated screen; a manual operating unit 8 for sendin8 operation commands to the si8nal processin8 unit 3, including commands for selecting a desired road map, setting a starting position at a given point on the selected road map, selectively indicating a travel trace, turning the selected road map and/or the travel trace on the selected road map, shiftin8 selected dots representing car positions on the road map, enlarging or reducing a selected area in the road map at a desired rate and performing other required 20535~2 operations.
In operation of thus constructed apparatus, a road map selectively read out from the road map storage medium 5 appears on the screen of the display unit 7, and current car positions are 8iven sequentially by dotting on the selected road on the screen to indicate a travel trace which the car has already run while the signal processing unit 3 is carrying out the necessary algorithmic operations to renew the X- and Y-coordinates of a current car position in the travel trace storing unit 4 wherefrom said data is read out and send to the display unit 7. Thus, as illustrated in Fig. 2, the screen of the display unit 7 shows the last estimated current car position Ml, the direction M2 in which the car is about to run from the last estimated current car position, and sequential car positions M3 plotted one after another from the starting position S.
The arrangement and operation described so far are the same as the conventional travel Position displaying apparatus described above.
In the conventional travel position displaying apparatus, positioning errors are apt toqCcumulate as the car runs a relatively long distance. Accordingly, the travel trace will continue to increasingly deviate from the selected road on the road map until the car can no longer be on the road map on the screen.
Such travel position displaying apparatus is improved according to the present invention, wherein the travel trace having sequential and last estimated current car positions thereon is corrected and put in registration with the true road found by selecting the road or roads in vicinity of the last estimated current car position and conducting the pattern matching procedure between the travel trace and each of selected roads. Specifically, the number of selected roads with respect to which the travel trace is to be checked for similarity is reduced to a minimum, but still adequate to permit the selection of true road and exact location of the car on the road map. Thus, the burden of patterq matching in the signal processing unit is reduced to a minimum.
An example of selection of the roads is described as follows:
The presumed current car position is set on the road and all branches, respectively, whereon the car is supposed to run the predetermined distance ahead from the starting position or from the last estimated and corrected current car position on the road map on the screen.
Referring to Fig. 4(a), if the car is running on a straight road having no branches within a predetermined distance Q from the last current car position P' corrected by the pattern matching procedure, the subsequent presumed 20~3~2 current position X is set at the predetermined distance Q
ahead from of the last current car position on the same road. Referring to Fig. 4(b), if the car is running on a straight road having branches within a predetermined distance Q from the last current car position P' corrected by the pattern matching procedure, the subsequent presumed current positions Xl, X2, and X3 are set at the predetermined distance Q ahead from of the last current car position P' on all the branches (where Ql~ Q2= Ql+ Q3 = Qlt Q4= Q )-Each time it is detected that the car ran a givenconstant distance Q, the signal processing unit 3 carries out the necessary algorithmic operation with reference to the coordinates of the position of the selected road appearing on the screen of the display unit 7 to automatically put presumed current car positions on the road, Each road on the road map is represented by a series of line ~egments obtained by linear approximation and the digital values of X- and Y-coordinates of the road's line segments are stored in the road map st~rage unit 5.
Next, a decision is made as to whether or not. the distance between each of the presumed current car positions and the last estimated current car position which deviates from all the roads is within a given allowance. If the road or roads are within such allowance, then the presumed current car positions being within such allowance are selected and will be subjected to pattern matching.
Referring to Fig. 5, the distances between presumed current car positions X (Xl, X2, and X3) and the estimated current car position P are indicated at D (D1, D2, and D3).
Presumed current car positions which meet the following equation (1) are estimated.
D s a L = M
where " Q" stands for a unit distance set, for instance, at 100 meters; "M~ stands for a predetermined allowance, for instance 50 meters; and "a " stands for a coefficient pertainin8 to the accuracy of the car positioning with reference to the running distance as a parameter and set, for instance, at 5%.
Referring to Fig. 5, if the presumed current car position X2 is selected as that meeting the equation (1), the road whereon the presumed current car position X2 exists will be "nominated" for pattern matching.
Later, each time the car ran the predetermined distance Q, the above-mentioned selection of the presumed current car position X is repeated.
Referring to Fig. 6, the road nominated for pattern matching is presented in the form of a pattern of a constant length L which is formed of a series of thus selected presumed current car positions X from the position 2053~Q2 P'. The road pattern of a fixed length L is compared with the car's travel trace of the same fixed length L in the following pattern matching process:
If the fixed length L of the pattern is short, a lar8e number of road patterns similar to the trace pattern of the car travel may be found on the road map increasing the possibility of erroneous selection, while if the fixed len~th L is long, the possibility of erroneous selection can be reduced but a large amount of data may be needed for pattern matching, thereby much time is required for data processing and also the capacity of the data processing and storing hardwares shall be increased. Accordingly, the fixed pattern length L is usually set at a value within 600 to 800 meters.
First, a trace pattern LP of the car travel and a nominated road pattern RP are converted into approximates of broken lines of equal length, for instance, 10 meters as illustrated in Figs. 7(a) and 7(b) respectively, and then vectorial angles a i(i= 1, 2, 3, ...n) of approximated line segments of the travel trace LP and vectorial angles ~ i(i= 1, 2, 3, ...n) of approximated line segments of the nominated road pattern RP with respect to the X-axis are calculated.
An rotation angle ~ of travel trace pattern RP is determined by averaging differences (a i-~ i) between 2 ~ Q 2 pattern LP and in the nominated road pattern RP.
Taking a rosd configuration error into consideration, pairs of vectors of the travel trace and road patterns, angular difference of which is less than a predetermined threshold value A, are omitted before the rotation angle is calculated.
I ai ~ > A ................... (3) Where "A" stands for a threshold value of angles between paired vectors, which is usually set at about 45~.
Second, as illustrated in Fig. 8, the travel trace pattern LP is shifted in parallel with the nominated road pattern RP until the current car position P at the head of the travel trace reaches to the last presumed current car position x' at the head of the road pattern RP, and then the travel trace pattern LP is turned about the current car position P by the angle ~ so as to put it on the road pattern RP.
Referring to Fig. 9, an area S formed between two patterns after rotation of the trace pattern LP by ~ i8 calculated. The smaller the area S is, the more similar both patterns are. Both patterns are considered to match with each other if a value S/L which stands for the area S
normalized by the given fixed length L of the area S is less than a predetermined threshold value C of similarity.
(S/L) < C .................... (4) -lZ-' , , 20~35Q2 with each other if a value S/L which stands for the area S
normalized by the given fixed length L of the area S is less than a predetermined threshold value C of similarity.
( S/L ) < C . . . . . . . (4) The threshold value C for judging similarity of patterns is usually set at about 8.
Referring to Fig. 10, the condition (S/L)<8 means that when both the travel trace pattern LP and the nominated road pattern RP are converted into straight lines respectively and the area S formed between both these linear patterns is determined by approximately calculating S= h- L/2, the value "h" will be less than 16, i.e. the maximum deviation between both patterns is less than 16 meters.
Finally, data on the current car position P are corrected so as to make the current car position P appear at a position x' on the nominated road pattern RP subjected to the pattern matching process, and also data on the travel trace pattern LP are corrected so as to bring the travel trace pattern onto the matched nominated road pattern RP if need be.
If the same matching condition such as pattern length L, threshold value A of angular variation, threshold value C of pattern similarity and etc. are applied to all cases of matchin8 between the trace and road patterns, the matching accuracy may be decreased, for instance, when the -- 2QS~5Q2 car running along a mountain roadway having meandering portions which have a decreased accuracy of digital map representation.
Namely, any meandering portion of the mountain roadway may have a large amount of error in digital mapping by linear approximation method in compari$on with other portions of the same roadway. Therefore, if a road pattern of a given fixed length L for a meandering portion is extracted from the digital map, said pattern may largely deviates from the travel trace pattern of a given fixed length L formed by the car running the meandering portion, thereby the pattern matching may not be performed.
In case of a superhighway, since it has a small number of curved portions and can be digitally mapped at high accuracy, namely, with less amount of error in linear approximation in comparison with ordinary roads in a city, it is possible to further improve the matching accuracy by employing matchin8 condition adapted for superhighway.
In view of the foregoing, the travel position displayin8 apparatus according to the present invention includes means for discriminating what class of road the car is running on, and means for changing pattern matching condition including parameters and reference values in accordance with the discrimination result.
The means for changing the pattern matching conditions trace pattern and a road pattern and optimally adapted for road classification are stored in a memory unit and will be selecti~ely read out to use;
(2) Sets of matching condition, each of which includes a set of parameters and threshold values necessary for matching between a travel trace pattern and a road pattern and optimally adapted for road classification, are stored in a memory unit and will be selectively read out to use.
The means for determ-n;ng what class of road the car is running on are included in the signal processing unit 3 and the determination procedure is carried out as follows:
First, each of line segments of equal length, by which the car travelling trace of a constant length L is linearly approximated, has an angle a to X-axis, i.e.
ai = {al, a2, a3, ~-- an }
which is differentiated numerically in 2-th order with respect to ai" = al ~2 ~ 2 al~l ~ al, then ai" = {al n ~ a2 ~ ~ a3 ~ ~ ~ ~ ~ an ~ } is obtained Frequency of changing a sign of each element in ~i" = {al", a2", a3", ~-- an" }, i.e. the number k of inflection points on the travel trace pattern is counted, which is normalized by the trace length L, thereby obtaining:
k' = k/L ~-- (5) ~ Q ~
where k' stands for the number of curves per unit distance.
Next, the measured value k' of the road is compared with a threshold value K for determining whether the road is mountainous or not:
k' > K ~-- (6) If the value k' is more than the value K, the road is judged to be mountainous. If the value k' is smaller than the value K, the road is judged to be of ordinary class.
The value K is set at about 0.02.
Fig. 11 is a flowchart showing a procedure for determination of the road classification.
The means for changing the pattern matching condition in response to a result of determination of classification of the road are provided in the signal processing unit 3 wherein the procedure will be performed in the following way:
In case that the road is judged to be of ordinary class the signal processing unit will employ standard preset values for the pattern matching procedure, that is, a common constant pattern length L = 600 ~ 800 meters for the travel trace pattern LP and nominated road pattern RP, a threshold value A = 45~ for angular difference and a threshold value C = 8 for similarity of patterns.
In case that the road is judged to be of mountain-pass class the signal processing unit changes the values of r 20~35Q2 threshold value A = 45~ for angular difference and a threshold value C = 8 for similarity of patterns.
In case that the road is iudged to be of mountain-pass class the signal processing unit changes the values of a parameter (L) and thresholds (A, C) to those optimally adapted for the mountain road pattern matching. Namely, since in case of a meandering portion of the mountain road the larger distance error is induced as pattern length L is increased, this parameter is modified to have a value of L'= L x 0.5 so as to shorten both the trace pattern LP
and the road pattern RP to be compared with each other.
However, the value L' is set at 600 meters if L'~600 m or it is set at 3000 meter if L'>3000 m.
In case of the mountain road, since there is a considerable unevenness of differences between angles of compared pairs of line segments of equal length by which the travel trace pattern LP and the nominated road pattern RP are approximated respectively in the form of a broken line, the threshold value A for angular deviation is changed from 45~ to 90~ .
Furthermore, in case of the mountain road, since there is a large amount of error in configuration of mapped road, the threshold value C for pattern similarity is changed from 8 to 10 so as to slacken the condition of similarity between the trace pattern LP and the road pattern RP.
20~3S02 Relating to means for discriminating what class of road the car is running, it is also possible to employ a variety of other methods such that, for example, a dispersion of angular differences of compared pair of line segments of equal length for approximating the trace pattern into a broken line is processed statistically to recognize class of the road.
It is also possible to adopt a variety of algorithms other than the fore-described for pattern matching procedure and, accordingly, to apply a variety of pattern matching conditions which include parameter and threshold values to be changed in accordance with the road classification and wh ich are also selectable depending upon the selected algorithm.
It is also possible to prepare and selectively use a plurality of al80ritllms each of which is optimally adapted to a specified class of roads, e.g. mountain-pass road, superhighway or other ordinary road.
Effect As be apparent from the foregoing description, the travel position displaying apparatus according to the present invention offers such an advantage that in matching between a travel trace pattern and a nominated road pattern on a road map so as to correct a current car position "
deviated from the road indicated Jthe map it is possible to apply means for discriminating what class of road the car is running on and means for changing the matching condition including parameters and threshold values necessary for pattern matching to be adaptable for the class of road, e.g. mountain road, superhighway and other ordinary road, taking into consideration that different class roads differ from each other in their digital mapping accuracy.
Brief Description of Drawings Fig. 1 is a bloc~ diagram showing a structure of an apparatus for displaying a current position of a moving body according to the present invention.
Fig. 2 shows an example of a road map image with a series of dots representing sequential current car positions appearing on a screen of the travel position displaying apparatus shown in Fig. 1.
Fig. 3 shows an another road map image having sequential current car positions departing from the road on the road map.
Figs. 4(a) and 4(b) show how presumed current car positions are put on a road and road branches for each increment of running distance, respectively.
Figs. 5 shows how the last estimated car position is related to corresponding presumed current car positions on ~ 2053502 the road map.
Fig. 6 shows how a road pattern to be nominated for pattern matching is formed.
Fig. 7(a) shows how a travel trace approximation is made by using straight increments of equal length.
Fig. 7(b) shows how a selected road pattern approxima-tion is made by using straight increments of equal length.
Fig. 8 shows how a travel trace and a selected road pattern are matched to each other.
Fig. 9 shows a discrepancy between a travel trace and a road pattern when they are laid over each other in pattern matching process.
Fig. 10 shows an equivalently illustrated discrepancy between a travel trace and a selected road pattern when they are laid over each other in pattern matching process.
Fig. 11 is a flow chart showing a procedure for recognizing the road classification.
1 ~-- Speed Sensor 2 ~-- Direction Sensor 3 ~-- Signal Processing Unit 4 ~-- Travel Trace Storage Unit 5 ~-- Road Map Storage Medium 6 ~-- Reader for Road Map Storage Medium 7 ~-- Display Unit 20~3S02 8 ~-- Manual Operation Unit LP--- Travel Trace RP--- Nominated Road
Detailed Description of the Invention Technical ScoPe The present invention relates to an apparatus for displayin8 a travel position, which is capable of indicating a current position of a movins body on a road ~ap presented on a screen.
Prior Art Recently, in attempt to guide a moving body, e.g. an autbmobile, an apparatus for displaying a current position of moving body has been developed, in which the current position of the automobile is sequentially estimated in 2ns3so~
data may include an increased amount of errors in defining its meandering portion having a series of sharply turning courses.
Consequently, when a car travelling along a mountain road, it is much difficult to make the car travel trace match with the road patterns obtained on the basis of digitally processed data and displayed on the screen.
Summary of the Invention In view of the foregoing, the present invention was made to provide an apparatus for displaying a current position of a moving body, which, in case the moving body departs from all the roads indicated on the road map screen, can accurately correct its current position on the screen by optimally performing an adaptive pattern matching between the travel trace and the pattern of a road where-along the moving body travelling, in due consideration of an accuracy of the road map based on the digitized data of the road depending upon its category, e.g., mountain road, superhighway and other ordinary road.
The present invention provides an apparatus for displaying a travel position which is capable of recognizing the class of a roadway whereon the moving body now is running and selecting pattern matching conditions including various kinds of parameters and threshold values in accordance with the recognized class of the road.
In accordance with this invention, apparatus for displaying a travel position comprises: (a) means for detecting a running distance travelled and a running direction of a moving body; (b) means for calculating X-and Y- coordinates of a current position of said moving body; (c) means for renewably presenting, on a display screen, the current position of said moving body on a road A
o ~
map read out from a road map storage medium; (d) means for accumulating data, in a memory device, on subsequent current positions of said moving body to form data on a travel trace; (e) means for matching between a travel trace pattern of said moving body and a selected road pattern by means of a given algorithm; (f) means for putting the travel trace on the road pattern for correcting the current position of said moving body deviated from the road on the map; (g) means for determining what class of road the moving body is running on by measuring a number of curves per unit distance; and (h) means for changing a pattern matching condition, including parameters and thresholds usable in the algorithm according to the result of a road class determination.
By another aspect the invention provides a machine-implemented method for displaying a travel position, which includes the steps of: (a) detecting a running distance travelled and a changing direction of a moving body; (b) calculating X- and Y- coordinates of a current position of the moving body; (c) renewably presenting, on a display screen, the current position of the moving body on a road map read out from a road map storage medium; (d) accumulating data, in a memory device, on subsequent current positions of said moving body to form data on a travel trace; (e) matching between a travel trace pattern of the moving body and a selected road pattern by means of a given algorithm; (f) putting the travel trace on the road pattern for correcting the current position of said moving body deviated from the road on the map; (g) determining what class of road the moving body is running on by measuring a number of curves per unit distance; and (h) changing a pattern matching condition, including parameters and thresholds usable in the algorithm according to the result of a road class determination.
2 ~
Brief Description of Drawings Fig. 1 is a block diagram showing a structure of an apparatus for displaying a current position of a moving body according to the present invention.
Fig. 2 shows an example of a road map image with a series of dots representing sequential current car positions appearing on a screen of the travel position displaying apparatus shown in Fig. 1.
Fig. 3 shows an another road map image having sequential current car positions departing from the road on the road map.
Figs. 4(a) and 4(b) show how presumed current car positions are put on a road and road branches for each increment of running distance, respectively.
Figs. 5 shows how the last estimated car position is related to corresponding presumed current car positions on the road map.
Fig. 6 shows how a road pattern to be nominated for pattern matching is formed.
Fig. 7(a) shows how a travel trace approximation is made by using straight increments of equal length.
Fig. 7(b) shows how a selected road pattern approximation is made by using straight increments of equal length.
Fig. 8 shows how a travel trace and a selected road pattern are matched to each other.
Fig. 9 shows a discrepancy between a travel trace and a road pattern when they are laid over each other in pattern matching process.
Fig. 10 shows an equivalently illustrated discrepancy between a travel trace and a selected road pattern when they are laid over each other in pattern matching process.
Fig. 11 is a flow chart showing a procedure for recognizing the road classification.
2 ~
Referring now to the drawings, a preferred embodiment of the present invention will be described in detail as follows:
It will be observed from Fig. l that a travel position displaying apparatus according to the present invention comprises: a speed sensor l for detecting a car's running speed; a direction sensor 2 which is capable of detecting any variation in angular speed in the yaw direction and generating a signal proportional to a change in direction of the car running; a signal processing unit 3 composed of a micro-computer which is capable of controlling the entire system, determining the running distance by multiplying the running speed measured by the speed sensor l by the time elapsed, determining a change in the running direction of - 5a -2053~Q2 micro-computer which is capable of controlling the entire system, determining the runnins distance by multiplyin8 the running speed measured by the speed sensor 1 by the time elapsed, determining a change in tlle running direction of the car by multiplying the angular speed detected by the direction sensor 2 by the time elapsed, and conducting a cumulative algorithmic operation of vectors to determine current car position in terms of X- and Y-coordinates for each unit running distance; a travel trace storage unit 4 for sequentially storing the X- and Y-coordinates of the current car positions as a finite continuous data set; a road map storage medium 5 for storing a plurality of road maps; a storage medium reading unit 6 for selectively reading different road maps; a display unit 7 for presenting a selected road map and the travel trace in terms of sequential current car positions and its runnin8 directions on an associated screen; a manual operating unit 8 for sendin8 operation commands to the si8nal processin8 unit 3, including commands for selecting a desired road map, setting a starting position at a given point on the selected road map, selectively indicating a travel trace, turning the selected road map and/or the travel trace on the selected road map, shiftin8 selected dots representing car positions on the road map, enlarging or reducing a selected area in the road map at a desired rate and performing other required 20535~2 operations.
In operation of thus constructed apparatus, a road map selectively read out from the road map storage medium 5 appears on the screen of the display unit 7, and current car positions are 8iven sequentially by dotting on the selected road on the screen to indicate a travel trace which the car has already run while the signal processing unit 3 is carrying out the necessary algorithmic operations to renew the X- and Y-coordinates of a current car position in the travel trace storing unit 4 wherefrom said data is read out and send to the display unit 7. Thus, as illustrated in Fig. 2, the screen of the display unit 7 shows the last estimated current car position Ml, the direction M2 in which the car is about to run from the last estimated current car position, and sequential car positions M3 plotted one after another from the starting position S.
The arrangement and operation described so far are the same as the conventional travel Position displaying apparatus described above.
In the conventional travel position displaying apparatus, positioning errors are apt toqCcumulate as the car runs a relatively long distance. Accordingly, the travel trace will continue to increasingly deviate from the selected road on the road map until the car can no longer be on the road map on the screen.
Such travel position displaying apparatus is improved according to the present invention, wherein the travel trace having sequential and last estimated current car positions thereon is corrected and put in registration with the true road found by selecting the road or roads in vicinity of the last estimated current car position and conducting the pattern matching procedure between the travel trace and each of selected roads. Specifically, the number of selected roads with respect to which the travel trace is to be checked for similarity is reduced to a minimum, but still adequate to permit the selection of true road and exact location of the car on the road map. Thus, the burden of patterq matching in the signal processing unit is reduced to a minimum.
An example of selection of the roads is described as follows:
The presumed current car position is set on the road and all branches, respectively, whereon the car is supposed to run the predetermined distance ahead from the starting position or from the last estimated and corrected current car position on the road map on the screen.
Referring to Fig. 4(a), if the car is running on a straight road having no branches within a predetermined distance Q from the last current car position P' corrected by the pattern matching procedure, the subsequent presumed 20~3~2 current position X is set at the predetermined distance Q
ahead from of the last current car position on the same road. Referring to Fig. 4(b), if the car is running on a straight road having branches within a predetermined distance Q from the last current car position P' corrected by the pattern matching procedure, the subsequent presumed current positions Xl, X2, and X3 are set at the predetermined distance Q ahead from of the last current car position P' on all the branches (where Ql~ Q2= Ql+ Q3 = Qlt Q4= Q )-Each time it is detected that the car ran a givenconstant distance Q, the signal processing unit 3 carries out the necessary algorithmic operation with reference to the coordinates of the position of the selected road appearing on the screen of the display unit 7 to automatically put presumed current car positions on the road, Each road on the road map is represented by a series of line ~egments obtained by linear approximation and the digital values of X- and Y-coordinates of the road's line segments are stored in the road map st~rage unit 5.
Next, a decision is made as to whether or not. the distance between each of the presumed current car positions and the last estimated current car position which deviates from all the roads is within a given allowance. If the road or roads are within such allowance, then the presumed current car positions being within such allowance are selected and will be subjected to pattern matching.
Referring to Fig. 5, the distances between presumed current car positions X (Xl, X2, and X3) and the estimated current car position P are indicated at D (D1, D2, and D3).
Presumed current car positions which meet the following equation (1) are estimated.
D s a L = M
where " Q" stands for a unit distance set, for instance, at 100 meters; "M~ stands for a predetermined allowance, for instance 50 meters; and "a " stands for a coefficient pertainin8 to the accuracy of the car positioning with reference to the running distance as a parameter and set, for instance, at 5%.
Referring to Fig. 5, if the presumed current car position X2 is selected as that meeting the equation (1), the road whereon the presumed current car position X2 exists will be "nominated" for pattern matching.
Later, each time the car ran the predetermined distance Q, the above-mentioned selection of the presumed current car position X is repeated.
Referring to Fig. 6, the road nominated for pattern matching is presented in the form of a pattern of a constant length L which is formed of a series of thus selected presumed current car positions X from the position 2053~Q2 P'. The road pattern of a fixed length L is compared with the car's travel trace of the same fixed length L in the following pattern matching process:
If the fixed length L of the pattern is short, a lar8e number of road patterns similar to the trace pattern of the car travel may be found on the road map increasing the possibility of erroneous selection, while if the fixed len~th L is long, the possibility of erroneous selection can be reduced but a large amount of data may be needed for pattern matching, thereby much time is required for data processing and also the capacity of the data processing and storing hardwares shall be increased. Accordingly, the fixed pattern length L is usually set at a value within 600 to 800 meters.
First, a trace pattern LP of the car travel and a nominated road pattern RP are converted into approximates of broken lines of equal length, for instance, 10 meters as illustrated in Figs. 7(a) and 7(b) respectively, and then vectorial angles a i(i= 1, 2, 3, ...n) of approximated line segments of the travel trace LP and vectorial angles ~ i(i= 1, 2, 3, ...n) of approximated line segments of the nominated road pattern RP with respect to the X-axis are calculated.
An rotation angle ~ of travel trace pattern RP is determined by averaging differences (a i-~ i) between 2 ~ Q 2 pattern LP and in the nominated road pattern RP.
Taking a rosd configuration error into consideration, pairs of vectors of the travel trace and road patterns, angular difference of which is less than a predetermined threshold value A, are omitted before the rotation angle is calculated.
I ai ~ > A ................... (3) Where "A" stands for a threshold value of angles between paired vectors, which is usually set at about 45~.
Second, as illustrated in Fig. 8, the travel trace pattern LP is shifted in parallel with the nominated road pattern RP until the current car position P at the head of the travel trace reaches to the last presumed current car position x' at the head of the road pattern RP, and then the travel trace pattern LP is turned about the current car position P by the angle ~ so as to put it on the road pattern RP.
Referring to Fig. 9, an area S formed between two patterns after rotation of the trace pattern LP by ~ i8 calculated. The smaller the area S is, the more similar both patterns are. Both patterns are considered to match with each other if a value S/L which stands for the area S
normalized by the given fixed length L of the area S is less than a predetermined threshold value C of similarity.
(S/L) < C .................... (4) -lZ-' , , 20~35Q2 with each other if a value S/L which stands for the area S
normalized by the given fixed length L of the area S is less than a predetermined threshold value C of similarity.
( S/L ) < C . . . . . . . (4) The threshold value C for judging similarity of patterns is usually set at about 8.
Referring to Fig. 10, the condition (S/L)<8 means that when both the travel trace pattern LP and the nominated road pattern RP are converted into straight lines respectively and the area S formed between both these linear patterns is determined by approximately calculating S= h- L/2, the value "h" will be less than 16, i.e. the maximum deviation between both patterns is less than 16 meters.
Finally, data on the current car position P are corrected so as to make the current car position P appear at a position x' on the nominated road pattern RP subjected to the pattern matching process, and also data on the travel trace pattern LP are corrected so as to bring the travel trace pattern onto the matched nominated road pattern RP if need be.
If the same matching condition such as pattern length L, threshold value A of angular variation, threshold value C of pattern similarity and etc. are applied to all cases of matchin8 between the trace and road patterns, the matching accuracy may be decreased, for instance, when the -- 2QS~5Q2 car running along a mountain roadway having meandering portions which have a decreased accuracy of digital map representation.
Namely, any meandering portion of the mountain roadway may have a large amount of error in digital mapping by linear approximation method in compari$on with other portions of the same roadway. Therefore, if a road pattern of a given fixed length L for a meandering portion is extracted from the digital map, said pattern may largely deviates from the travel trace pattern of a given fixed length L formed by the car running the meandering portion, thereby the pattern matching may not be performed.
In case of a superhighway, since it has a small number of curved portions and can be digitally mapped at high accuracy, namely, with less amount of error in linear approximation in comparison with ordinary roads in a city, it is possible to further improve the matching accuracy by employing matchin8 condition adapted for superhighway.
In view of the foregoing, the travel position displayin8 apparatus according to the present invention includes means for discriminating what class of road the car is running on, and means for changing pattern matching condition including parameters and reference values in accordance with the discrimination result.
The means for changing the pattern matching conditions trace pattern and a road pattern and optimally adapted for road classification are stored in a memory unit and will be selecti~ely read out to use;
(2) Sets of matching condition, each of which includes a set of parameters and threshold values necessary for matching between a travel trace pattern and a road pattern and optimally adapted for road classification, are stored in a memory unit and will be selectively read out to use.
The means for determ-n;ng what class of road the car is running on are included in the signal processing unit 3 and the determination procedure is carried out as follows:
First, each of line segments of equal length, by which the car travelling trace of a constant length L is linearly approximated, has an angle a to X-axis, i.e.
ai = {al, a2, a3, ~-- an }
which is differentiated numerically in 2-th order with respect to ai" = al ~2 ~ 2 al~l ~ al, then ai" = {al n ~ a2 ~ ~ a3 ~ ~ ~ ~ ~ an ~ } is obtained Frequency of changing a sign of each element in ~i" = {al", a2", a3", ~-- an" }, i.e. the number k of inflection points on the travel trace pattern is counted, which is normalized by the trace length L, thereby obtaining:
k' = k/L ~-- (5) ~ Q ~
where k' stands for the number of curves per unit distance.
Next, the measured value k' of the road is compared with a threshold value K for determining whether the road is mountainous or not:
k' > K ~-- (6) If the value k' is more than the value K, the road is judged to be mountainous. If the value k' is smaller than the value K, the road is judged to be of ordinary class.
The value K is set at about 0.02.
Fig. 11 is a flowchart showing a procedure for determination of the road classification.
The means for changing the pattern matching condition in response to a result of determination of classification of the road are provided in the signal processing unit 3 wherein the procedure will be performed in the following way:
In case that the road is judged to be of ordinary class the signal processing unit will employ standard preset values for the pattern matching procedure, that is, a common constant pattern length L = 600 ~ 800 meters for the travel trace pattern LP and nominated road pattern RP, a threshold value A = 45~ for angular difference and a threshold value C = 8 for similarity of patterns.
In case that the road is judged to be of mountain-pass class the signal processing unit changes the values of r 20~35Q2 threshold value A = 45~ for angular difference and a threshold value C = 8 for similarity of patterns.
In case that the road is iudged to be of mountain-pass class the signal processing unit changes the values of a parameter (L) and thresholds (A, C) to those optimally adapted for the mountain road pattern matching. Namely, since in case of a meandering portion of the mountain road the larger distance error is induced as pattern length L is increased, this parameter is modified to have a value of L'= L x 0.5 so as to shorten both the trace pattern LP
and the road pattern RP to be compared with each other.
However, the value L' is set at 600 meters if L'~600 m or it is set at 3000 meter if L'>3000 m.
In case of the mountain road, since there is a considerable unevenness of differences between angles of compared pairs of line segments of equal length by which the travel trace pattern LP and the nominated road pattern RP are approximated respectively in the form of a broken line, the threshold value A for angular deviation is changed from 45~ to 90~ .
Furthermore, in case of the mountain road, since there is a large amount of error in configuration of mapped road, the threshold value C for pattern similarity is changed from 8 to 10 so as to slacken the condition of similarity between the trace pattern LP and the road pattern RP.
20~3S02 Relating to means for discriminating what class of road the car is running, it is also possible to employ a variety of other methods such that, for example, a dispersion of angular differences of compared pair of line segments of equal length for approximating the trace pattern into a broken line is processed statistically to recognize class of the road.
It is also possible to adopt a variety of algorithms other than the fore-described for pattern matching procedure and, accordingly, to apply a variety of pattern matching conditions which include parameter and threshold values to be changed in accordance with the road classification and wh ich are also selectable depending upon the selected algorithm.
It is also possible to prepare and selectively use a plurality of al80ritllms each of which is optimally adapted to a specified class of roads, e.g. mountain-pass road, superhighway or other ordinary road.
Effect As be apparent from the foregoing description, the travel position displaying apparatus according to the present invention offers such an advantage that in matching between a travel trace pattern and a nominated road pattern on a road map so as to correct a current car position "
deviated from the road indicated Jthe map it is possible to apply means for discriminating what class of road the car is running on and means for changing the matching condition including parameters and threshold values necessary for pattern matching to be adaptable for the class of road, e.g. mountain road, superhighway and other ordinary road, taking into consideration that different class roads differ from each other in their digital mapping accuracy.
Brief Description of Drawings Fig. 1 is a bloc~ diagram showing a structure of an apparatus for displaying a current position of a moving body according to the present invention.
Fig. 2 shows an example of a road map image with a series of dots representing sequential current car positions appearing on a screen of the travel position displaying apparatus shown in Fig. 1.
Fig. 3 shows an another road map image having sequential current car positions departing from the road on the road map.
Figs. 4(a) and 4(b) show how presumed current car positions are put on a road and road branches for each increment of running distance, respectively.
Figs. 5 shows how the last estimated car position is related to corresponding presumed current car positions on ~ 2053502 the road map.
Fig. 6 shows how a road pattern to be nominated for pattern matching is formed.
Fig. 7(a) shows how a travel trace approximation is made by using straight increments of equal length.
Fig. 7(b) shows how a selected road pattern approxima-tion is made by using straight increments of equal length.
Fig. 8 shows how a travel trace and a selected road pattern are matched to each other.
Fig. 9 shows a discrepancy between a travel trace and a road pattern when they are laid over each other in pattern matching process.
Fig. 10 shows an equivalently illustrated discrepancy between a travel trace and a selected road pattern when they are laid over each other in pattern matching process.
Fig. 11 is a flow chart showing a procedure for recognizing the road classification.
1 ~-- Speed Sensor 2 ~-- Direction Sensor 3 ~-- Signal Processing Unit 4 ~-- Travel Trace Storage Unit 5 ~-- Road Map Storage Medium 6 ~-- Reader for Road Map Storage Medium 7 ~-- Display Unit 20~3S02 8 ~-- Manual Operation Unit LP--- Travel Trace RP--- Nominated Road
Claims (6)
1. An apparatus for displaying a travel position, comprising:
(a) means for detecting a running distance travelled and a running direction of a moving body;
(b) means for calculating X- and Y- coordinates of a current position of said moving body;
(c) means for renewably presenting, on a display screen, the current position of said moving body on a road map read out from a road map storage medium;
(d) means for accumulating data, in a memory device, on subsequent current positions of said moving body to form data on a travel trace;
(e) means for matching between a travel trace pattern of said moving body and a selected road pattern by means of a given algorithm;
(f) means for putting the travel trace on the road pattern for correcting the current position of said moving body deviated from the road on the map;
(g) means for determining what class of road the moving body is running on by measuring a number of curves per unit distance; and (h) means for changing a pattern-matching condition, including parameters and thresholds usable in the algorithm, according to the result of a road class determination.
(a) means for detecting a running distance travelled and a running direction of a moving body;
(b) means for calculating X- and Y- coordinates of a current position of said moving body;
(c) means for renewably presenting, on a display screen, the current position of said moving body on a road map read out from a road map storage medium;
(d) means for accumulating data, in a memory device, on subsequent current positions of said moving body to form data on a travel trace;
(e) means for matching between a travel trace pattern of said moving body and a selected road pattern by means of a given algorithm;
(f) means for putting the travel trace on the road pattern for correcting the current position of said moving body deviated from the road on the map;
(g) means for determining what class of road the moving body is running on by measuring a number of curves per unit distance; and (h) means for changing a pattern-matching condition, including parameters and thresholds usable in the algorithm, according to the result of a road class determination.
2. The apparatus for displaying a travel position of claim 1, further comprising:
means for selectively using a plurality of algorithms, according to a result of said road class determination, each of which includes a pattern-matching condition, including parameters and thresholds set for a specific class of roads.
means for selectively using a plurality of algorithms, according to a result of said road class determination, each of which includes a pattern-matching condition, including parameters and thresholds set for a specific class of roads.
3. The apparatus for displaying a travel position of claim 1 or 2, further comprising:
means for selectively using a plurality of pattern-matching conditions, according to a result of said road class determination, each of which includes parameters and thresholds set for a specific class of roads.
means for selectively using a plurality of pattern-matching conditions, according to a result of said road class determination, each of which includes parameters and thresholds set for a specific class of roads.
4. A machine-implemented method for displaying a travel position, comprising the steps of:
(a) detecting a running distance travelled and a changing direction of a moving body;
(b) calculating X- and Y- coordinates of a current position of the moving body;
(c) renewably presenting, on a display screen, the current position of the moving body on a road map read out from a road map storage medium;
(d) accumulating data, in a memory device, on subsequent current positions of said moving body to form data on a travel trace;
(e) matching between a travel trace pattern of the moving body and a selected road pattern by means of a given algorithm;
(f) putting the travel trace on the road pattern for correcting the current position of said moving body deviated from the road on the map;
(g) determining what class of road the moving body is running on by measuring a number of curves per unit distance; and (h) changing a pattern-matching condition, including parameters and thresholds usable in the algorithm, according to the result of a road class determination.
(a) detecting a running distance travelled and a changing direction of a moving body;
(b) calculating X- and Y- coordinates of a current position of the moving body;
(c) renewably presenting, on a display screen, the current position of the moving body on a road map read out from a road map storage medium;
(d) accumulating data, in a memory device, on subsequent current positions of said moving body to form data on a travel trace;
(e) matching between a travel trace pattern of the moving body and a selected road pattern by means of a given algorithm;
(f) putting the travel trace on the road pattern for correcting the current position of said moving body deviated from the road on the map;
(g) determining what class of road the moving body is running on by measuring a number of curves per unit distance; and (h) changing a pattern-matching condition, including parameters and thresholds usable in the algorithm, according to the result of a road class determination.
5. The machine-implemented method of claim 4, wherein a plurality of algorithms are selectively used according to the result of the road class determination, and further wherein each algorithm used includes a pattern-matching condition, including parameters and thresholds set for a specific class of roads.
6. The machine-implemented method of claim 4 or 5, wherein a plurality of pattern-matching conditions is selectively used according to the result of the road class determination, and further wherein each pattern-matching condition used includes parameters and thresholds set for a specific class of roads.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2327103A JP2657581B2 (en) | 1990-11-28 | 1990-11-28 | Current position display device of moving object |
| JP327103 | 1990-11-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2053502A1 CA2053502A1 (en) | 1992-05-29 |
| CA2053502C true CA2053502C (en) | 1999-01-05 |
Family
ID=18195328
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002053502A Expired - Lifetime CA2053502C (en) | 1990-11-28 | 1991-10-16 | Apparatus for displaying a travel position |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5266948A (en) |
| EP (1) | EP0487864B1 (en) |
| JP (1) | JP2657581B2 (en) |
| CA (1) | CA2053502C (en) |
| DE (1) | DE69111573T2 (en) |
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| EP0514887B1 (en) * | 1991-05-21 | 1997-04-16 | Matsushita Electric Industrial Co., Ltd. | Vehicle position detecting apparatus |
| JP3227741B2 (en) * | 1991-11-18 | 2001-11-12 | 住友電気工業株式会社 | Overspeed prediction device |
| DE69326643T2 (en) * | 1992-07-20 | 2000-04-13 | Aisin Aw Co | Navigation system for vehicle steering |
| JP3157923B2 (en) * | 1992-10-20 | 2001-04-23 | パイオニア株式会社 | Distance error correction method for navigation device |
| JP3409377B2 (en) * | 1993-08-09 | 2003-05-26 | 松下電器産業株式会社 | Navigation device |
| US5369589A (en) * | 1993-09-15 | 1994-11-29 | Trimble Navigation Limited | Plural information display for navigation |
| JPH08159806A (en) * | 1994-10-04 | 1996-06-21 | Murata Mfg Co Ltd | Azimuth sensor aand azimuth/distance sensor |
| US5826212A (en) * | 1994-10-25 | 1998-10-20 | Honda Giken Kogyo Kabushiki Kaisha | Current-position map and three dimensional guiding objects displaying device for vehicle |
| DE69512511T2 (en) * | 1994-11-14 | 2000-01-27 | Zanavy Informatics Kk | CARD DISPLAY DEVICE FOR VEHICLES |
| US6125325A (en) | 1996-04-25 | 2000-09-26 | Sirf Technology, Inc. | GPS receiver with cross-track hold |
| US6041280A (en) * | 1996-03-15 | 2000-03-21 | Sirf Technology, Inc. | GPS car navigation system |
| US6393046B1 (en) | 1996-04-25 | 2002-05-21 | Sirf Technology, Inc. | Spread spectrum receiver with multi-bit correlator |
| US6198765B1 (en) | 1996-04-25 | 2001-03-06 | Sirf Technologies, Inc. | Spread spectrum receiver with multi-path correction |
| US6917644B2 (en) * | 1996-04-25 | 2005-07-12 | Sirf Technology, Inc. | Spread spectrum receiver with multi-path correction |
| US6047017A (en) * | 1996-04-25 | 2000-04-04 | Cahn; Charles R. | Spread spectrum receiver with multi-path cancellation |
| US6018704A (en) * | 1996-04-25 | 2000-01-25 | Sirf Tech Inc | GPS receiver |
| EP0817134A3 (en) * | 1996-07-05 | 1999-10-27 | Robert Bosch Gmbh | Apparatus for determining the distance travelled by a motor vehicle |
| US6249542B1 (en) | 1997-03-28 | 2001-06-19 | Sirf Technology, Inc. | Multipath processing for GPS receivers |
| US6776792B1 (en) | 1997-04-24 | 2004-08-17 | Advanced Cardiovascular Systems Inc. | Coated endovascular stent |
| JP3975472B2 (en) * | 1997-06-02 | 2007-09-12 | ソニー株式会社 | Digital map enlargement / reduction display method, digital map enlargement / reduction display apparatus, and storage medium storing digital map enlargement / reduction display program |
| US6282231B1 (en) | 1999-12-14 | 2001-08-28 | Sirf Technology, Inc. | Strong signal cancellation to enhance processing of weak spread spectrum signal |
| SE0004096D0 (en) | 2000-11-08 | 2000-11-08 | Nira Automotive Ab | Positioning system |
| JP2005345201A (en) * | 2004-06-01 | 2005-12-15 | Denso Corp | Travel track display device and program |
| WO2006042689A1 (en) * | 2004-10-18 | 2006-04-27 | Societe De Technologie Michelin | Method of establishing a sinuosity index for a digital mapping system |
| SE529949C2 (en) * | 2006-05-26 | 2008-01-15 | Scania Cv Abp | Device and system for classification of vehicle environment |
| JP4797901B2 (en) * | 2006-09-12 | 2011-10-19 | 株式会社デンソー | Current position display device, navigation device, program |
| JP2008089517A (en) * | 2006-10-04 | 2008-04-17 | Sony Corp | Azimuth discrimination device, azimuth discrimination method, and azimuth discrimination program |
| US8285485B2 (en) * | 2010-03-18 | 2012-10-09 | Harman International Industries, Incorporated | Vehicle navigation system with route determination based on a measure of sportiness |
| DE102016215061A1 (en) | 2016-08-12 | 2018-02-15 | Bayerische Motoren Werke Aktiengesellschaft | Provision of driver assistance |
| JP7389541B2 (en) * | 2017-08-10 | 2023-11-30 | いすゞ自動車株式会社 | Traffic management device, traffic management method, and traffic management system |
| SE542743C2 (en) * | 2018-11-06 | 2020-07-07 | Mobilaris Mce Ab | Method and device for determining the position of a moving object |
| CN112597822B (en) * | 2020-12-11 | 2023-08-15 | 国汽(北京)智能网联汽车研究院有限公司 | Vehicle track determination method and device, electronic equipment and computer storage medium |
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| JPS5895775A (en) * | 1981-12-02 | 1983-06-07 | 株式会社日立製作所 | Display for position of running vehicle |
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| JPH0711424B2 (en) * | 1987-08-07 | 1995-02-08 | 本田技研工業株式会社 | Driving route display device |
| CA1326273C (en) * | 1987-08-07 | 1994-01-18 | Akira Iihoshi | Apparatus for displaying travel path |
| US5043902A (en) * | 1987-12-28 | 1991-08-27 | Aisin Aw Co., Ltd. | Vehicular navigation apparatus |
| JP2680318B2 (en) * | 1987-12-28 | 1997-11-19 | アイシン・エィ・ダブリュ株式会社 | Navigation device |
| JP2618254B2 (en) * | 1988-02-15 | 1997-06-11 | 本田技研工業株式会社 | Travel route display device |
| JP2646453B2 (en) * | 1988-04-28 | 1997-08-27 | マツダ株式会社 | Vehicle navigation system |
| JPH07119617B2 (en) * | 1988-07-05 | 1995-12-20 | マツダ株式会社 | Vehicle navigation system |
| JP2633630B2 (en) * | 1988-07-05 | 1997-07-23 | マツダ株式会社 | Navigation device for vehicles |
| JPH02137097A (en) * | 1988-11-18 | 1990-05-25 | Nissan Motor Co Ltd | Elevated express-highway travelling recognition device |
-
1990
- 1990-11-28 JP JP2327103A patent/JP2657581B2/en not_active Expired - Lifetime
-
1991
- 1991-10-04 DE DE69111573T patent/DE69111573T2/en not_active Expired - Lifetime
- 1991-10-04 EP EP91116993A patent/EP0487864B1/en not_active Expired - Lifetime
- 1991-10-16 CA CA002053502A patent/CA2053502C/en not_active Expired - Lifetime
- 1991-11-27 US US07/798,962 patent/US5266948A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0487864A1 (en) | 1992-06-03 |
| CA2053502A1 (en) | 1992-05-29 |
| DE69111573T2 (en) | 1996-01-18 |
| JP2657581B2 (en) | 1997-09-24 |
| JPH04195084A (en) | 1992-07-15 |
| US5266948A (en) | 1993-11-30 |
| DE69111573D1 (en) | 1995-08-31 |
| EP0487864B1 (en) | 1995-07-26 |
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