| 摘要 |
PROBLEM TO BE SOLVED: To provide position information, even when a reception intensity of GPS signals is weak through compensating for phase inversion of a navigation message and integrating the phase over a long time. SOLUTION: A base station 20 receives GPS signals 11 at all times, and extracts and holds information for assisting a GPS receiver 30 to receive signals and to calculate position. The base station 20 sends assisting information via a communication line 40, when the GPS receiver 30 needs information. The base station 20 assists in synchronizing of the reception time of the GPS receiver 30. The GPS receiver 30 receives the GPS signal 11, generates an intermediate frequency signal by down-converting the GPS signal, and stores the A/D converted data into a storage part. The GPS receiver 30 integrates GPS signal data stored in the memory part 33, while matching the phase, on the basis of the assisting information (satellite navigation message and phase inversion information) supplied from the base station 20. The GPS receiver 30 calculates the position with the use of the integrated GPS data.
|
