| 摘要 |
PROBLEM TO BE SOLVED: To provide a satellite positioning system capable of performing uninterrupted positioning. SOLUTION: In the case that a navigation system 11 has predicted an entry in an upper blocked space in the near future at the time of a progression to P1, an assist positioning control part 15 controls a wireless communication device 17 and a GPS receiver 16 to establish connection between the GPS receiver 16 and a positioning server 4. After this, in the case that a C/N ratio of the GPS receiver 16 has degraded below a prescribed threshold value TH at the time of an entry in the upper blocked space 400 at a location S and a progression to P2 in the upper blocked space 400, the assist positioning control part 15 sets assist positioning mode in the GPS receiver 16. The GPS receiver 16 set in assist positioning mode immediately starts to acquire auxiliary data from the positioning server 4 having connection already established at the location P1 and performs positioning by a network assist method. COPYRIGHT: (C)2009,JPO&INPIT |
