| 摘要 |
PURPOSE:To reduce the influence of multipass, etc., by performing position measurement this time and last time within a prescribed time, and nullifying vehicle speed, etc., this when it exceeds a threshold value decided by the vehicle speed, etc. CONSTITUTION:Firstly, a position measuring interval DELTAt between position measuring time tCF in this step and position measuring time tLF in the last step is found (S4). Thence, after the time tLF stored in a RAM is replaced (S5) by the time tCF for the next processing, it is decided (S6) whether or not the position measurement this time is performed within a prescribed threshold time tMASK from the position measurement last time. When the position measurement this time is performed within the prescribed threshold time tMASK from that last time, a vehicle travel azimuth difference DELTAD between this time and last time and a vehicle speed difference DELTAS between this time and last time are found, and it is decided (S8) whether or not they exceed the threshold value DMASK for travel azimuth and the threshold value DMASK for vehicle speed. When they exceed the threshold values DMASK and SMASK, travel azimuth DCF and vehicle speed SCF are assumed as invalid data receiving the influence of the multipass, etc., and they are outputted to an external device. |
