Navigation equipment which determines current position dependent on difference between calculated value of self-contained navigation and measured value of radio navigation
First Claim
1. A navigation equipment which is installed on a mobile object in order to produce a current position of the mobile object as an output, comprising:
- radio navigation means for measuring the current position of said mobile object on the basis of electric waves received from artificial satellites;
azimuth measurement means for measuring a traveling azimuth of said mobile object on the basis of at least one of an angular velocity and a geomagnetic angle;
distance measurement means for measuring a driven distance of said mobile object;
memory means for storing road map information therein;
self-contained navigation means for estimating one of said current position of said mobile object and a drive history thereof up to a current time by use of the traveling azimuth measured by said azimuth measurement means and the driven distance measured by said distance measurement means up to the current time since a given drive starting position, and then collating one of the estimated current position or the estimated drive history with the road map information read out of said memory means, thereby determining a current position of said mobile object; and
position correction means for delivering the determined current position of said self-contained navigation means as the final current position in a case where said determined current position of said self-contained navigation means and the measured current position of said radio navigation means do not differ in excess of a predetermined distance, and for delivering said measured current position of said radio navigation means as the final current position and also giving said self-contained navigation means said measured current position of said radio navigation means as a new drive starting point in a case where the determined and measured current positions differ in excess of the predetermined distance, said position correction means collates said determined current position of said self-contained navigation means with said road map information, thereby deciding if said determined current position lies either on or in the vicinity of a road; and
upon deciding that said determined current position lies either on or in the vicinity of the road, said position correction means delivers said determined current position of said self-contained navigation means as said final current position and does not give said self-contained navigation means said measured current position of said radio navigation means as the new drive starting point even in the case where said determined and measured current positions differ in excess of said predetermined distance.
1 Assignment
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Accused Products
Abstract
In a case where a flag delivered from a self-contained navigation processor indicates that a position measured by the self-contained navigation processor lies on or in the vicinity of a road contained in road map information, a position correction processor selects and delivers the measured position of the self-contained navigation processor as an output current position. In any other case, the position correction processor calculates the distance between a position measured by a radio navigation processor and the position measured by the self-contained navigation processor. On condition that the distance between the coordinates of the two positions has, at least, a predetermined value, the position correction processor decides the measured position of the radio navigation processor as a current position, and it corrects to the current position a drive starting coordinate point which is managed by the self-contained navigation processor.
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Citations
10 Claims
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1. A navigation equipment which is installed on a mobile object in order to produce a current position of the mobile object as an output, comprising:
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radio navigation means for measuring the current position of said mobile object on the basis of electric waves received from artificial satellites; azimuth measurement means for measuring a traveling azimuth of said mobile object on the basis of at least one of an angular velocity and a geomagnetic angle; distance measurement means for measuring a driven distance of said mobile object; memory means for storing road map information therein; self-contained navigation means for estimating one of said current position of said mobile object and a drive history thereof up to a current time by use of the traveling azimuth measured by said azimuth measurement means and the driven distance measured by said distance measurement means up to the current time since a given drive starting position, and then collating one of the estimated current position or the estimated drive history with the road map information read out of said memory means, thereby determining a current position of said mobile object; and position correction means for delivering the determined current position of said self-contained navigation means as the final current position in a case where said determined current position of said self-contained navigation means and the measured current position of said radio navigation means do not differ in excess of a predetermined distance, and for delivering said measured current position of said radio navigation means as the final current position and also giving said self-contained navigation means said measured current position of said radio navigation means as a new drive starting point in a case where the determined and measured current positions differ in excess of the predetermined distance, said position correction means collates said determined current position of said self-contained navigation means with said road map information, thereby deciding if said determined current position lies either on or in the vicinity of a road; and
upon deciding that said determined current position lies either on or in the vicinity of the road, said position correction means delivers said determined current position of said self-contained navigation means as said final current position and does not give said self-contained navigation means said measured current position of said radio navigation means as the new drive starting point even in the case where said determined and measured current positions differ in excess of said predetermined distance. - View Dependent Claims (2, 3, 4)
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5. A navigation equipment which is installed on a mobile object in order to produce a current position of the mobile object as an output, comprising:
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radio navigation means for measuring the current position of said mobile object on the basis of electric waves received from artificial satellites; azimuth measurement means for measuring a traveling azimuth of said mobile object on the basis of at least one of an angular velocity and a geomagnetic angle; distance measurement means for measuring a driven distance of said mobile object; memory means for storing road map information therein; self-contained navigation means for estimating one of said current position of said mobile object and a drive history thereof up to a current time by use of the traveling azimuth measured by said azimuth measurement means and the driven distance measured by said distance measurement means up to the current time since a given drive starting position, and then collating one of the estimated current position or the estimated drive history with the road map information read out of said memory means, thereby determining a current position of said mobile object; and position correction means for delivering the determined current position of said self-contained navigation means as the final current position in a case where said determined current position of said self-contained navigation means and the measured current position of said radio navigation means do not differ in excess of a predetermined distance, and for delivering said measured current position of said radio navigation means as the final current position and also giving said self-contained navigation means said measured current position of said radio navigation means as a new drive starting point in a case where the determined and measured current positions differ in excess of the predetermined distance, said position correction means collates said determined current position of said self-contained navigation means with said road map information, thereby deciding if said determined current position lies either on or in the vicinity of a road;
upon deciding that said determined current position lies either on or in the vicinity of the road, said position correction means further decides a probability at which said determined current position lies either on or in the vicinity of said road according to the current positions measured by said self-contained navigation means during a period of predetermined time length up to said current time; and
upon deciding that the probability has, at least, a predetermined magnitude, said position correction means delivers said determined current position of said self-contained navigation means as said final current position and does not give said self-contained navigation means said measured current position of said radio navigation means as the new drive starting point even in the case where said determined and measured current positions differ in excess of said predetermined distance. - View Dependent Claims (6, 7, 8, 9, 10)
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Specification