Vehicle position and azimuth computing system
First Claim
1. A vehicle position and azimuth computing apparatus comprising:
- measurement position computing means for obtaining measurement positions of a vehicle by performing a measurement in accordance with a GPS (global positioning system);
a gyro for detecting an angular velocity of the vehicle;
a speed sensor for detecting a travel distance of the vehicle;
on-vehicle position and azimuth computing means for computing both an on-vehicle position and an on-vehicle azimuth of the vehicle based on the angular velocity and the travel distance of the vehicle;
straight running detecting means for detecting a straight running condition of the vehicle based on the angular velocity;
longitude line computing means for obtaining a longitude line as a first regression line obtained by regressing longitudes of the measurement positions during the straight running of the vehicle to the moving distance from a starting position of the straight running of the vehicle;
latitude line computing means for obtaining a latitude line as a second regression line obtained by regressing latitudes of the measurement positions during the straight running of the vehicle to the moving distance from the starting position of the straight running of the vehicle;
on-vehicle azimuth modifying means for computing an azimuth of the vehicle during the straight running condition of the vehicle based on an inclination of a longitude line versus latitude line during the straight running condition of the vehicle, which is obtained from an inclination of the longitude line and an inclination of the latitude line, and modifying the on-vehicle azimuth computed by said on-vehicle position and azimuth computing means in response thereto; and
on-vehicle position modifying means for modifying the on-vehicle position computed by said on-vehicle position and azimuth computing means on the basis of a vehicle position computed by using a longitude and a latitude which are obtained by applying a travel distance, which extends from the straight running starting position to a vehicle position, to both the longitude line and the latitude line.
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Abstract
An vehicle position and azimuth computing apparatus is constructed to correct both positional errors and azimuth errors caused by the accumulation of a sensor error and a map error and to provide both high positional precision and high azimuth precision. To this end, the vehicle position and azimuth computing apparatus operates to detect both an angular velocity and a moving distance of a vehicle, to compute an on-vehicle position and on-vehicle azimuth, and to detect a straight running condition of the vehicle. Then, after the GPS measurement positions during the straight running of the vehicle have been obtained, regression lines are obtained by regressing the longitudes and latitudes of the measurement positions during the straight running of the vehicle to the moving distance from the straight running starting position of the vehicle. Both a vehicle position and a vehicle azimuth are computed based on the regression lines during the straight running of the vehicle, and then an on-vehicle position and an on-vehicle azimuth, which have been computed based on the detected values of the angular velocity and the moving distance of the vehicle, are modified by using the vehicle position and azimuth obtained based on the GPS measurement data.
59 Citations
16 Claims
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1. A vehicle position and azimuth computing apparatus comprising:
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measurement position computing means for obtaining measurement positions of a vehicle by performing a measurement in accordance with a GPS (global positioning system); a gyro for detecting an angular velocity of the vehicle; a speed sensor for detecting a travel distance of the vehicle; on-vehicle position and azimuth computing means for computing both an on-vehicle position and an on-vehicle azimuth of the vehicle based on the angular velocity and the travel distance of the vehicle; straight running detecting means for detecting a straight running condition of the vehicle based on the angular velocity; longitude line computing means for obtaining a longitude line as a first regression line obtained by regressing longitudes of the measurement positions during the straight running of the vehicle to the moving distance from a starting position of the straight running of the vehicle; latitude line computing means for obtaining a latitude line as a second regression line obtained by regressing latitudes of the measurement positions during the straight running of the vehicle to the moving distance from the starting position of the straight running of the vehicle; on-vehicle azimuth modifying means for computing an azimuth of the vehicle during the straight running condition of the vehicle based on an inclination of a longitude line versus latitude line during the straight running condition of the vehicle, which is obtained from an inclination of the longitude line and an inclination of the latitude line, and modifying the on-vehicle azimuth computed by said on-vehicle position and azimuth computing means in response thereto; and on-vehicle position modifying means for modifying the on-vehicle position computed by said on-vehicle position and azimuth computing means on the basis of a vehicle position computed by using a longitude and a latitude which are obtained by applying a travel distance, which extends from the straight running starting position to a vehicle position, to both the longitude line and the latitude line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15)
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14. A vehicle position and azimuth computing apparatus comprising:
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vehicle position and azimuth information gathering means for gathering information on a position and azimuth of a vehicle from outside of the vehicle; on-vehicle position and azimuth modifying means for modifying the position and azimuth of the vehicle based on the position and azimuth information gathered by said vehicle position and azimuth information gathering means; road data gathering means for gathering road data from road map information; on-vehicle position and azimuth correcting means for comparing, at every predetermined travelling distance, both a vehicle position and a vehicle azimuth, which have been gathered by said vehicle position and azimuth information gathering means, with both an on-road position and an on-road azimuth, which have been gathered by said road data gathering means, respectively, and for making a correction of the on-vehicle position and on-vehicle azimuth by making replacement thereof by the on-road position and on-road azimuth, respectively, when both a positional difference and an azimuth difference therebetween are smaller than respective values which are determined by a moving distance and a rotational angle measured from a vehicle position, where a latest correction has been made, up to the present vehicle position; and correction times recording means for recording the number of times of corrections which have been made within a latest predetermined travelling distance, wherein said on-vehicle position and azimuth modifying means is inhibited from performing modifications of the on-vehicle position and the on-vehicle azimuth, respectively, when the number of times of corrections recorded in said correction times recording means is equal to or greater than a predetermined value.
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16. A vehicle position an azimuth computing apparatus as claimed in claimed 1, wherein said gyro is a vibration gyro.
Specification