| 摘要 |
PROBLEM TO BE SOLVED: To reduce power consumption by shortening the energizing time of a GPS receiving part in a position calculation apparatus equipped with the GPS receiving part and a communication part for performing the communication with a center station capable of acquiring the ephemeris of GPS. SOLUTION: The position calculation apparatus is equipped with the GPS receiving part 1 receiving the radio wave from a GPS satellite 11 to calculate the position, a memory part 3 for holding the ephemeris or the like, a timepiece part 4, a backup battery 5, a power supply part 6, a power supply switch part 7 turning the supply of power to the GPS receiving part 1 on/off, the communication part 8 performing the communication with the center station 10, a display/ operation part 9 for performing the display of a position and the on/off operation of the power supply and a control part 2 performing the on/off control of the power supply switch part 7 or the control of the whole of the apparatus. The control part 2 turns the power supply of the GPS receiving part 1 on by the power supply switch part 7 after the communication part 8 receives the ephemeris from the center station 10.
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