| 摘要 |
PURPOSE: To enhance position measuring accuracy by correcting the error of altitude information on a map. CONSTITUTION: Data of navigation message and phase of pseudonoise code synchronized with the message are demodulated with a signal receiving demodulator from a receiving signal of electric wave from at least three GPS satellites and outputted to a position measuring operation part 13. The position of the GPS satellite is calculated there, and the distance to the signal receiving position is calculated from the phase of the pseudonoise code. The signal receiving position is calculated with altitude information Db on a map. Signal receiving position data Da of latitude, longitude, and altitude obtained by coordinate transformation of the signal receiving position are outputted. Altitude error information Dd obtained by calculating the error of the altitude information Db on the map by using altitude information Dc obtained by position measuring calculation of the last time by a altitude error calculation part 14 is multiplied by a value less than l-The value obtained is added to the error of the altitude information Db on the map, and the data obtained is outputted to the position measuring operation part 13 as altitude information De. By repeating these processes, the error (offset value) of the altitude information Db on the map is gradually corrected. |
