| 摘要 |
PURPOSE:To accurately estimate the current position of a vehicle by even if the reception state of a GPS receiver becomes worse by finding coordinate data on the current position from the output data of the GPS receiver and a set altitude value when a CPS receiver which outputs coordinate data on the absolute position of the vehicle is in a two-dimensional position measurement state. CONSTITUTION:The device is equipped with a decision means which decides that the GPS receiver 4 enters the two-dimensional position measurement state and a temporary current position setting means which sets a temporary current position each as a function of a system controller 5. Further, the device is equipped with an altitude setting means which finds the altitude value at the temporary current position from the coordinate data on the temporary current position and the output data of the GPS receiver 4 and a means which finds the coordinate data on the current position from the GPS data and the altitude value set by the altitude setting means. Consequently, even if the reception state of the GPS receiver is inferior and data accuracy deteriorates in the two-dimensional position measurement state, the current position of the vehicle can accurately be estimated. |
