| 摘要 |
PROBLEM TO BE SOLVED: To provide a real-time clock for a GPS receiver. SOLUTION: A navigation satellite receiver is provided with a real-time clock capable of serving as a slave with respect to a highly accurate time base of a GPS system. At this time, the amount of correction and operating temperatures are observed. It is supposed that the operating temperatures affect frequency error the most, when the real-time clock cannot be slaved to the time base of GPS later. Even during powered-down state of the receiver, the real-time clock is held in an energized state. Temperature correction is performed on a free-running frequency. At power-up of the receiver the next time, it is possible to instantly obtain time more accurate than an error of 1 millisecond or shorter in one day for use in the initialization processing of other receivers. COPYRIGHT: (C)2003,JPO |
