| 摘要 |
PURPOSE:To calculate an accurate current position by taking into consideration a time lag from receipt of a GPS signal to the end of operation for position measurement, and making a correction for an estimated current position with the current position calculated by a GPS position measurement method. CONSTITUTION:A computer 2 operates a travel locus on the basis of a travel distance and a travel direction detected from the output signals of a travel speed sensor 1 and a gyroscope 4. The travel locus and a road map in a CD-ROM 5 are collated with each other, and an estimated current position and travel route are calculated by an estimated navigation method. The result is corrected by use of a current position and travel direction obtained from a GPS receiver 3 via GPS position measurement. In this case, a time lag from signal receipt to current position output (time for travel up to a position of a1-a2) is inputted from the receiver 3, and an estimated prior position b1 corresponding to the time lag found through the estimated navigation method is read out for correcting a position C1 obtained from current GPS position measurement. In addition, an estimated position (b11-b13) and b2 are read from the receiver 3 and the estimated current position b2 is updated, using the latest position C2 obtainable through the re-calculation of each estimated position after the position C1 as reference. |
