Apparatus for displaying travel path

Claim 1

An apparatus for displaying a travel path, the apparatus comprising: means for successively estimating coordinates of a current position of a moving body; means for storing data relating to the successively estimated current positions of the moving body and data relating to the coordinates of roads along which the body may move; display means for showing successively determined and/or estimated current positions of the moving body on a map including the roads; and processing means, characterised in that the processing means is adapted such that: at predetermined intervals a presumable current position is calculated for the body with respect to one or more road, whose position differs from the previously determined position of the moving body by a distance corresponding to the distance which the moving body is estimated to have travelled during the preceding predetermined interval; for each presumable current position, a check is made as to whether a given relationship between the presumable current position and the current estimated position is satisfied, and the or each presumable current position for which the relationship is satisfied is selected; for each selected presumable current position, a road pattern leading to the selected presumable current position from the previously determined current position is compared with a pattern of successive estimated positions from the previously determined current position to the current estimated position; and one such selected presumable current position is determined, on the basis of such comparison, to be the current position of the moving body.

Claim 2

An apparatus for displaying a travel path, the apparatus comprising: means for successively estimating coordinates of a current position of a moving body; means for storing data relating to the successively estimated current positions of the moving body and data relating to the coordinates of roads along which the body may move; display means for showing successively determined and/or estimated current positions of the moving body on a map including the roads; and processing means, characterised in that the processing means is adapted such that: at predetermined intervals a presumable current position is calculated for the body with respect to one or more road, whose position differs from the previously determined position of the moving body by a distance corresponding to the distance which the moving body is estimated to have travelled during the preceding predetermined interval; for each presumable current position, a check is made as to whether a given relationship between the presumable current position and the current estimated position is satisfied, and the or each presumable current position for which the relationship is satisfied is selected; for each selected presumable current position, a road pattern leading to the selected presumable current position from the previously determined current position is compared with a pattern of successive estimated positions from the previously determined current position to the current estimated position; and one such selected presumable current position is determined, on the basis of such comparison, to be the current position of the moving body.

Claim 5

An apparatus according to any preceding claim, wherein the given relationship between the presumable current position and the current estimated position is satisfied when the distance between the two positions is calculated to be less than a predetermined distance.

Claim 6

An apparatus according to one of claims 1, 2 or 3, wherein the given relationship between the selected presumable current position and the current estimated position is satisfied when the angle, between the directed in which the moving body is about to leave the current estimated position and the direction in which the road having the presumable current position thereon extends, is calculated to be less than a predetermined angle.

Claim 7

An apparatus according to any preceding claim, wherein pattern comparison is carried out, after each predetermined interval, between the pattern of successive estimated current positions and a selected road map.

Claim 8

An apparatus according to one of claims 1 to 5, wherein, after each predetermined interval, an angular increment is determined, and, each time an accumulation of such angular increments reaches a predetermined amount, pattern comparison is carried out between the pattern of successive estimated current positions and a road pattern which is determined by connecting successive presumable current positions.

Claim 10

An apparatus according to any preceding claim, wherein a selected road on the road map and a pattern of successive estimated current positions are each approximated by a respective line each constituted by a series of straight segments of equal length, and the respective lines are subjected to pattern comparison.

Claim 12

An apparatus for displaying travel path in which as a moving body is travelled, the current position of the moving body is sequentially estimated in terms of X- and Y- coordinates, and the data of the estimated current position is stored in a memory; and the current position of the moving body on a road map appearing on a screen is sequentially renewed on the basis of the data of the estimated current position thus stored, characterised in that it comprises: first processing means for setting, each time the moving body runs a predetermined running distance, a presumable current position corresponding to an estimated current position of the moving body each on a roads, or their branch roads on which the moving body is supposed to run, with reference to the previously stored X- and Y- coordinates of a road or roads of the road map; second processing means for making each time the moving body runs the said predetermined running distance, a decision as to whether or not a given correlation is established between a selected presumable current position and the last estimated current position of the moving body, in the affirmative case, selecting a road having presumable current position thereon; third processing means for carrying out a pattern-­matching between the so selected road pattern and the travel trace pattern running to the last estimated current position retrieved from said memory; and fourth processing means for putting the travel course of the moving body in registration with the selected road of the road map.

Claim 13

An apparatus for displaying travel path in which as a moving body is travelled, the current position of the moving body is sequentially estimated in terms of X- and Y- coordinates, and the data of the estimated current position is stored in a memory; and the current position of the moving body on a road map appearing on a screen is sequentially renewed on the basis of the data of the estimated current position thus stored, characterised in that it comprises: first processing means for setting, each time the moving body runs a predetermined running distance, a presumable current position corresponding to an estimated current position of the moving body each on a roads, or their branch roads on which the moving body is supposed to run, with reference to the previously stored X- and Y- coordinates of a road or roads of the road map; second processing means for making each time the moving body runs the said predetermined running distance, a decision as to whether or not a given correlation is established between a selected presumable current position and the last estimated current position of the moving body, in the affirmative case, selecting a road having presumable current position thereon; third processing means for carrying out a pattern-­matching between the so selected road pattern and the travel trace pattern running to the last estimated current position retrieved from said memory; and fourth processing means for putting the travel course of the moving body in registration with the selected road of the road map.

Claim 14

An apparatus as claimed in any preceding claim, wherein the given relationship between a presumable current position and a current estimated position is satisfied if the two positions are separated by less than a first predetermined distance and wherein the processor is adapted such that, if the given relationship is not satisfied for any presumable current position, a search is made in the road map for a road running within a second predetermined distance from the last estimated current position of the moving body, and a presumable current position is tentatively set on the road thus found, or on the road closest to the last estimated current position of the moving body if a plurality of roads should be found within the second predetermined distances and such that the tentatively set presumable current position is moved along the same road after each predetermined interval, and the tentatively set presumable current position is identified with the real presumable current position when the distance between the latest tentatively presumable current position and the last estimated current position of the moving body are found to be separated by less than the first predetermined distance.