Patent ID: 7778775

Claim:
A position detecting apparatus for receiving GPS signals transmitted from satellites, and for detecting a position using the received PS signals, GPS signal including main frame data and the main frame data of one cycle further including “m” pieces of sub-frame data consisting of first sub-frame data to m-th sub-frame data transmitted from the satellite in a time series manner, the apparatus comprising: a power source for supplying power from a battery; a receiving unit for receiving GPS signal in an operation mode and for ceasing receiving GPS signal in an inoperative mode, the receiving unit, when kept in the operation mode, being supplied with power from the power source, and the receiving unit, when kept in the inoperative mode, being supplied with no power from the power source; an operation control unit for switching the receiving unit from the inoperative mode to the operation mode, and for switching the receiving unit from the operation mode to the inoperative mode; a judging unit for judging whether or not all the “m” pieces of sub-frame data have been acquired by the receiving unit, when the receiving unit is switched from the inoperative mode to the operation mode by the operation control unit; a time calculating unit for, when the judging unit determines that all the “m” pieces of sub-frame data have not been acquired, calculating a time at which the receiving unit is to be intermittently switched from the inoperative mode to the operation mode in synchronization with transmission of the sub-frame data which has not been acquired by the receiving unit, and for instructing the operation control unit to control operation of the receiving unit based on the calculated time; and a position calculating unit for, when the judging unit determines that all the “m” pieces of sub-frame data have been acquired, calculating a current position of the apparatus using positional information included in the acquired “m” pieces of sub-frame data.