FIXED STATION AND DGPS USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a DGPS (differention global positioning system) that effectively utilizes a public line and reduces the communications traffic from a fixed station to a terminal. SOLUTION: The fixed station has a first GPS (global positioning system) signal receiving section which obtains a navigation message by receiving GPS signals respectively transmitted from GPS satellites moving around the earth at high altitudes at a fixed point of known coordinates, a correction value calculating section which calculates a correction value from the pseudo ranges between the GPS satellites and fixed point calculated by using the information on the orbits of the satellites contained in the navigation message, and a first communication control section which is connected to the public line and transmits correction information to a specific terminal, and is characterized in that the fixed station is also provided with a communications-traffic reducing means which inputs the correction value and reduces the communications traffic of the correction information and disposed between the correction value calculating section and the first communication control section. COPYRIGHT: (C)2004,JPO