Patent ID: 7715279

Claim:
A time correction device comprising: a reception unit that receives satellite signals transmitted from at least one positioning information satellite orbiting the Earth; a time correction information storage unit that stores time correction information for correcting time information produced by a time information generating unit; a time information correction unit for correcting the time information; single positioning-information-satellite-referenced time correction information used by the reception unit to generate first time correction information based on the satellite signal from a single positioning information satellite; and plural positioning-information-satellite-referenced time correction information used by the reception unit for positioning and to generate second time correction information based on satellite signals from a plurality of positioning information satellites; wherein the received satellite signals contain only telemetry (TLM) data followed by handover word (HOW) data; the time correction device further contains transmission delay time information denoting the time until a particular satellite signal transmitted from the at least one positioning information satellite can be received; the time correction information is generated based on the received TLM and HOW data and the transmission delay time information; and the reception unit enters a sleep mode from immediately after receiving the HOW data in a first subframe until receiving the TLM data in a second subframe; and wherein the reception unit has selection information for selecting the first time correction information or the second time correction information based on capturability information denoting whether a satellite signal from the positioning information satellites can be captured, and a time correction selection and execution unit for selecting the first time correction information or the second time correction information based on the selection information and correcting the time based on the selected time correction information.