| 摘要 |
PURPOSE: To enable a GPS navigation device to continuously output its present position with high accuracy regardless of the number of receivable GPS satellites by providing a measuring section, etc., which measures the changing rates of the pseudo ranges to the GPS satellites. CONSTITUTION: A switching section 10 sends the measured results of a pseudo range changing rate measuring section 8 to a first calculating section 12 which calculates the speed vector of moving bodies when a receiving state judgment section 6 judges that the number of receivable satellites is 3 or to a second calculating section 16 which calculates the speed vector of moving bodies when the judged number is less than 3. The section 12 calculates the speed vector of a moving body by using the present position information of the moving body measured by means of a GPS position measuring section 7 and the changing rates of the pseudo ranges to the satellites measured by the measuring section 8. The section 16 calculates the speed vector of the moving body from the changing rates of pseudo ranges, pseudo ranges measured by a pseudo range measuring section 9, and the advancing bearing of the moving body calculated by a moving body advancing bearing calculating section 14. A moving body position estimating section 18 estimates the present position of the moving body by integrating the speed vectors. |
