| 摘要 |
PURPOSE: A system for operating a precise digital map by editing a map image according to geographic information is provided to reflect a location of a shore line made by a tide to navigation. CONSTITUTION: A lifting device(210) lifts a lifting stand in an information generating unit. A light receiving unit(222) receives an optical signal and a frequency signal of a transmitter(300). The transmitter and a sensing device checks an accurate location of the information generating unit. The transmitter transmits the frequency signal and the optical signal at the same time. A receiving network(221) of the sensing device and the light receiving unit receive the frequency signal and the optical signal with a time difference. |
