Track information generating device, track information generating method, and computer-readable storage medium

1. A track information generating device comprising:

a self-contained navigation track acquisition unit that acquires a self-contained navigation track that is a track of a vehicle indicated by a plurality of time-series pieces of self-contained navigation information obtained from a speed sensor and a direction sensor on the vehicle;

a GPS track acquisition unit that acquires a GPS track that is a track of the vehicle indicated by a plurality of time-series pieces of GPS information obtained from a GPS sensor on the vehicle, each time-series pieces of GPS information including GPS accuracy information that indicates an accuracy of the piece of GPS information; and

a self-contained navigation information correcting unit that:

rotates and translates the self-contained navigation track to a location and orientation having the highest degree of coincidence between the self-contained navigation track and the GPS track;

determines a rotation angle for rotating the self-contained navigation track on the basis of a representative value of direction differences between directions of the vehicle, indicated by the pieces of self-contained navigation information at multiple time points, and directions of the vehicle, indicated by the pieces of GPS information at multiple time points;

determines the representative value of the direction differences on the basis of a frequency distribution of the direction differences, which is generated so that a frequency increases with an increase in the accuracy of the GPS information, indicated by the corresponding GPS accuracy information, and determines a representative value of the position differences on the basis of a frequency distribution of the position differences, which is generated so that a frequency increases with an increase in the accuracy of the GPS information, indicated bathe corresponding GPS accuracy information;

determines a translation amount for translating the self-contained navigation track on the basis of a representative value of position differences between positions of the vehicle, indicated by the pieces of self-contained navigation information at multiple time points, and positions of the vehicle, indicated by the pieces of GPS information at multiple time points;

sets a correction target of the self-contained navigation information on the basis of the rotated and translated the self-contained navigation track;

corrects the self-contained navigation information by reducing a difference between the correction target and the self-contained navigation information; and

compares the rotated and translated self-contained navigation track with the GPS track to correct the self-contained navigation information by reducing a difference between the self-contained navigation track and the GPS track.

2. The track information generating device according to claim 1 , wherein

the self-contained navigation information correcting unit compares the self-contained navigation track with the GPS track in a distance that is reduced with an increase in the accuracies of the pieces of GPS information, indicated by the corresponding pieces of GPS accuracy information.

3. A track information generating method comprising:

acquiring, with a processor, a self-contained navigation track that is a track of a vehicle indicated by a plurality of time-series pieces of self-contained navigation information obtained from a speed sensor and a direction sensor on the vehicle;

acquiring, with the processor, a GPS track that is a track of the vehicle indicated by a plurality of time-series pieces of GPS information obtained from a GPS sensor on the vehicle, each time-series pieces of GPS information including GPS accuracy information that indicates an accuracy of the piece of GPS information;

rotating and translating, with the processor, the self-contained navigation track to a location and orientation having the highest degree of coincidence between the self-contained navigation track and the GPS track;

determining, with the processor, a rotation angle for rotating the self-contained navigation track on the basis of a representative value of direction differences between directions of the vehicle, indicated by the pieces of self-contained navigation information at multiple time points, and directions of the vehicle, indicated by the pieces of GPS information at multiple time points;

determining, with the processor, the representative value of the direction differences on the basis of a frequency distribution of the direction differences, which is generated so that a frequency increases with an increase in the accuracy of the GPS information, indicated by the corresponding GPS accuracy information, and determines a representative value of the position differences on the basis of a frequency distribution of the position differences, which is generated so that a frequency increases with an increase in the accuracy of the GPS information, indicated by the corresponding GPS accuracy information;

determining, with the processor, a translation amount for translating the self-contained navigation track on the basis of a representative value of position differences between positions of the vehicle, indicated by the pieces of self-contained navigation information at multiple time points, and positions of the vehicle, indicated by the pieces of GPS information at multiple time points;

setting, with the processor, a correction target of the self-contained navigation information on the basis of the rotated and translated the self-contained navigation track;

correcting, with the processor, the self-contained navigation information by reducing a difference between the correction target and the self-contained navigation information; and

comparing, with the processor, the rotated and translated self-contained navigation track with the GPS track to correct the self-contained navigation information by reducing a difference between the self-contained navigation track and the GPS track.

4. A non-transitory computer-readable storage medium that stores computer-executable instructions for performing a track information generating method comprising:

acquiring a self-contained navigation track that is a track of a vehicle indicated by a plurality of time-series pieces of self-contained navigation information obtained from a speed sensor and a direction sensor on the vehicle;

acquiring a GPS track that is a track of the vehicle indicated by a plurality of time-series pieces of GPS information obtained from a GPS sensor on the vehicle;

rotating and translating the self-contained navigation track to a location and orientation having the highest degree of coincidence between the self-contained navigation track and the GPS track;

determining a rotation angle for rotating the self-contained navigation track on the basis of a representative value of direction differences between directions of the vehicle, indicated by the pieces of self-contained navigation information at multiple time points, and directions of the vehicle, indicated by the pieces of GPS information at multiple timepoints;

determining the representative value of the direction differences on the basis of a frequency distribution of the direction differences, which is generated so that a frequency increases with an increase in the accuracy of the GPS information, indicated by the corresponding GPS accuracy information, and determines a representative value of the position differences on the basis of a frequency distribution of the position differences, which is generated so that a frequency increases with an increase in the accuracy of the GPS information, indicated by the corresponding GPS accuracy information;

determining a translation amount for translating the self-contained navigation track on the basis of a representative value of position differences between positions of the vehicle, indicated by the pieces of self-contained navigation information at multiple time points, and positions of the vehicle, indicated by the pieces of GPS information at multiple time points;

setting a correction target of the self-contained navigation information on the basis of the rotated and translated the self-contained navigation track;

correcting the self-contained navigation information by reducing a difference between the correction target and the self-contained navigation information; and

comparing the rotated and translated self-contained navigation track with the GPS track to correct the self-contained navigation information by reducing a difference between the self-contained navigation track and the GPS track.