Apparatus for displaying travel path

• US 4,963,864 A
• Filed: 07/27/1988
• Issued: 10/16/1990
• Est. Priority Date: 08/07/1987
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Matsumoto, Yoshiyuki, Iihoshi, Akira, Nakamura, Yukinobu, Nishio, Tomoyuki
• Primary Examiner(s): Orsino, Joseph A.
• Assistant Examiner(s): Swarthout, Brent A.
• Application Number:
  US07/224,985
• Time in Patent Office: 811 Days
• Field of Search: 340/995, 340/990, 340/988, 73/178 R, 364/449, 364/444, 364/460
• US Class Current: 340/995.22
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G09B 29/106 using electronic means

Abstract

Disclosed is a travel path displaying apparatus for indicating the current position of an automobile running on a selected road in a road map appearing on an associated screen. A cumulation of errors in estimating sequential current positions will cause an incorrect indication of the automobile'"'"'s position on the screen and the automobile will depart from all the roads appearing on the screen. In order to find the correct road on which the automobile is traveling it is necessary to carry out pattern matching between the travel trace and each of a number of selected roads, thereby determining which road is closest to the travel trace in shape. The apparatus permits selection of the least possible number of roads for pattern matching, thus permitting quick determination as to the road on which the automobile is traveling and as to the direction in which it is traveling.

Claims

1. An apparatus for displaying the travel path of a moving body wherein the current position of the moving body is cumulatively calculated and sequentially renewed on a road map displaying road patterns on a screen by arithmetically processing estimated current positions of the moving body in terms of X- and Y- coordinates while measuring the moving body'"'"'s running distance and detecting its direction of travel and sequentially storing the X- and Y- coordinates of the estimated current positions, the running distance and the direction of travel in a memory, characterized in that it comprises:

first processing means for automatically setting a presumed current position corresponding to an estimated current position on the road map each time the moving body runs a predetermined running distance, the presumed current position being set at a predetermined distance interval on each road on which the moving body is supposed to run, with reference to X- and Y- coordinates of the road patterns, the X- and Y- coordinates of the road patterns being previously stored in a memory;

second processing means for determining, each time the moving body runs the predetermined running distance, whether an angle between a vector extending in the direction in which the moving body travels as it leaves the last estimated current position of the moving body and a vector extending in the direction in which the road extends from the selected presumably current position on the road is within a predetermined angle range and, when such determination is in the affirmative, selecting a road pattern having the presumed current position thereon as a selected road pattern;

third processing means for arithmetically processing a pattern-matching of the selected road pattern and a travel trace extending from the last estimated current position retrieved from the memory; and

fourth processing means for correcting the travel trace of the moving body so that it coincides with the road pattern to which the pattern-matching between the travel trace and the selected road pattern of the moving body has been effected,

wherein the moving body'"'"'s angle of travel is successively determined each time the moving body has moved a predetermined running distance and, each time the added values of the respective angles thus determined becomes larger than a predetermined value, a pattern matching is collectively carried out between the moving body'"'"'s travel trace during the period when the moving body'"'"'s angles of travel are successively determined and have been added together, and the selected road pattern on the map extending from the resumed current position selected in correspondence to the current position of the moving body through a plurality of presumed current positions thus far selected.

2. An apparatus for displaying the travel path of a moving body wherein the current position of the moving body is cumulatively calculated and sequentially renewed on a road map displaying road patterns on a screen by arithmetically processing estimated current positions of the moving body in terms of X- and Y- coordinates while measuring the moving body'"'"'s running distance and detecting its direction of travel and sequentially storing the X- and Y- coordinates of the estimated current positions, the running distance and the direction of travel in a memory, characterized in that it comprises:

first processing means for automatically setting a presumed current position corresponding to an estimated current position on the road map each time the moving body runs a predetermined running distance, the presumed current position being set at a predetermined distance interval on each road on which the moving body is supposed to run, with reference to X- and Y- coordinates of the road patterns, the X- and Y- coordinates of the road patterns being previously stored in a memory;

second processing means for determining, each time the moving body runs the predetermined running distance, whether an angle between a vector extending in the direction in which the moving body travels as it leaves the last estimated current position of the moving body and a vector extending in the direction in which the road extends from the selected presumably current position on the road is within a predetermined angle range and, when such determination is in the affirmative, selecting a road pattern having the presumed current position thereon as a selected road pattern;

third processing means for arithmetically processing a pattern-matching of the selected road pattern and a travel trace extending from the last estimated current position retrieved from the memory; and

fourth processing means for correcting the travel trace of the moving body so that it coincides with the road pattern to which the pattern-matching between the travel trace and the selected road pattern of the moving body has been effected, wherein the predetermined angle range is increased at a given rate each time the moving body travels a predetermined running distance.

3. An apparatus for displaying the travel path of a moving body wherein the current position of the moving body is cumulatively calculated and sequentially renewed on a road map displaying road patterns on a screen by arithmetically processing estimated current positions of the moving body in terms of X- and Y- coordinates while measuring the moving body'"'"'s running distance and detecting the moving body'"'"'s direction of travel and sequentially storing the X- and Y -coordinates of the estimated current positions, the running distance and the direction of travel in a memory, characterized in that it comprises:

first processing means for automatically setting a presumed current position corresponding to an estimated current position on the road map each time the moving body runs a predetermined running distance, the presumed current position being set at a predetermined distance interval on each road on which the moving body is supposed to run, with reference to X- and Y- coordinates of the road patterns, the X- and Y- coordinates of the road patterns being previously stored in a memory;

second processing means for determining, each time the moving body runs the predetermined running distance, whether the distance between the presumed current position and a last estimated current position of the moving body exists within a first predetermined distance range and, when such determination is in the affirmative, selecting a road pattern having the presumed current position thereon as a selected road pattern;

third processing means for arithmetically processing a pattern-matching of the selected road pattern and a travel trace extending from the last estimated current position retrieved from the memory;

fourth processing means for correcting the travel trace of the moving body so that it coincides with the selected road pattern to which the pattern-matching between the travel trace and the selected road pattern of the moving body has been effected;

fifth processing means for locating a selected road pattern on the road map on the display screen within a second predetermined distance range measured from the last estimated current position of the moving body when a selected road pattern cannot be located within the first predetermined distance range, and tentatively setting a presumed current position on the selected road pattern or, if more than one road pattern is located within the second predetermined distance range, on the road pattern closest to the last estimated current position of the moving body; and

sixth processing means for renewing the tentatively set presumed current position on the road pattern each time the moving body travels the predetermined running distance and identifying the tentatively set presumed current position as the presumed current position when the distance between a last renewed tentatively set presumed current position and a last estimated current position of the moving body is found to be within the first predetermined distance range.

4. An apparatus for displaying the travel path of a moving body according to claim 3 wherein the second predetermined distance range is increased as the moving body'"'"'s running distance increases.