Time Adjustment Device, Timekeeping Device with a Time Adjustment Device, and a Time Adjustment Method

• US 20090034372A1
• Filed: 07/18/2008
• Published: 02/05/2009
• Est. Priority Date: 08/02/2007
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Fujisawa, Teruhiko
• Granted Patent: US 8,077,551 B2
• Time in Patent Office: Days
• US Class Current: 368/14
• CPC Class Codes: G04R 20/04 Tuning or receiving; Circuits therefor
• CPC Class Codes: G04R 20/06 Decoding time data; Circuits therefor
• CPC Class Codes: G04R 60/12 inside metal cases

Abstract

A time adjustment device having a time information generating unit that produces time information and outputs the generated time information; a reception unit that receives satellite signals transmitted sequentially from a positioning information satellite in subframe information units where a plurality of subframe information units each containing satellite-time-related information and at least one subframe information unit containing satellite health information is a unit, the satellite-time-related information is the time-related information of the positioning information satellite, and the satellite health information denotes an operating condition of the positioning information satellite; an external input unit that outputs command information instructing the reception unit to receive in response to external input; a reception timing configuration unit that sets the start time of reception by the reception unit so that the satellite signal is received immediately or at a predetermined timing based on command information from the external input unit; and a time adjustment information storage unit that stores the satellite-time-related information of the satellite signal received by the reception unit as time adjustment information. The generated time information is corrected based on the time adjustment information, and reception by the reception unit starts when the start timing comes.

Claims

1. A time adjustment device comprising:

a time information generating unit that produces time information and outputs the generated time information;

a reception unit that receives satellite signals transmitted sequentially from a positioning information satellite in subframe information units where

a plurality of subframe information units each containing satellite-time-related information and at least one subframe information unit containing satellite health information is a unit,

the satellite-time-related information is the time-related information of the positioning information satellite, and

the satellite health information denotes an operating condition of the positioning information satellite;

an external input unit that outputs command information instructing the reception unit to receive in response to external input;

a reception timing configuration unit that sets the start time of reception by the reception unit so that the satellite signal is received immediately or at a predetermined timing based on command information from the external input unit; and

a time adjustment information storage unit that stores the satellite-time-related information of the satellite signal received by the reception unit as time adjustment information;

wherein the generated time information is corrected based on the time adjustment information; and

reception by the reception unit starts when the start timing comes.

2. The time adjustment device described in claim 1, wherein:

the positioning information satellite is a GPS satellite;

the satellite signal transmission unit is the five subframe information units from subframe 1 to subframe 5;

the satellite health information is contained in subframe 1; and

the reception unit receives the satellite-time-related information and satellite health information in subframe 1.

3. The time adjustment device described in claim 1, wherein:

the reception unit has a decision unit that determines if the received satellite-time-related information is correct; and

the time adjustment information is the satellite-time-related information determined by the decision unit to be correct.

4. The time adjustment device described in claim 3, wherein:

if the current time adjustment, which is the amount the generated time information was corrected based on the time adjustment information, exceeds a threshold value offset, which is an offset time corresponding to the time passed from the generated time information the last time the generated time information was corrected,

the reception unit receives the satellite-time-related information in a plural number of following subframe information units, and stores the satellite-time-related information in the received plural number of following subframe information units as the satellite time information for the respective subframe information units;

any one of at least two satellite time information values for which the difference therebetween matches the difference between the subframe information units containing the at least two satellite time information values is selected; and

the generated time information is corrected based on the selected satellite time information.

5. The time adjustment device described in claim 2, wherein:

subframe 1 to subframe 5 each contain a subframe ID number;

the reception unit starts reception immediately when a receive command is asserted by the external input unit if the start timing of reception by the reception unit is set to start reception immediately;

the reception timing configuration unit sets the start timing for receiving the next subframe 1 based on the subframe ID number of the first subframe received by the reception unit, pauses reception by the reception unit until the start timing for reception of the next subframe 1 arrives, and resumes reception by the reception unit when the start timing for reception of the next subframe 1 arrives; and

the reception unit thereby receives the satellite-time-related information and satellite health information from the next subframe 1.

6. The time adjustment device described in claim 1, wherein:

there is a plurality of positioning information satellites;

the reception unit has a condition evaluation unit that determines the operating condition of the positioning information satellite based on the satellite health information; and

the reception unit receives the satellite signal from a different positioning information satellite based on the result output by the condition evaluation unit.

7. The time adjustment device described in claim 1, wherein:

if the time passed to the present since the last time the satellite health information was received is greater than or equal to a predetermined time,

the reception unit receives subframe 1 as the subframe information unit containing the satellite-time-related information and satellite health information.

8. A timekeeping device with a time adjustment device comprising:

a time information generating unit that produces time information and outputs the generated time information;

a reception unit that receives satellite signals transmitted sequentially from a positioning information satellite in subframe information units where

a plurality of subframe information units each containing satellite-time-related information and at least one subframe information unit containing satellite health information is a unit,

the satellite-time-related information is the time-related information of the positioning information satellite, and

the satellite health information denotes an operating condition of the positioning information satellite;

an external input unit that outputs command information instructing the reception unit to receive in response to external input;

a reception timing configuration unit that sets the start time of reception by the reception unit so that the satellite signal is received immediately or at a predetermined timing based on command information from the external input unit; and

a time adjustment information storage unit that stores the satellite-time-related information of the satellite signal received by the reception unit as time adjustment information;

wherein the generated time information is corrected based on the time adjustment information; and

reception by the reception unit starts when the start timing comes.

9. A time adjustment method comprising:

a time information generating unit that produces time information and outputs the generated time information;

a reception unit that receives satellite signals transmitted sequentially from a positioning information satellite in subframe information units where

a plurality of subframe information units each containing satellite-time-related information and at least one subframe information unit containing satellite health information is a unit,

the satellite-time-related information is the time-related information of the positioning information satellite, and

the satellite health information denotes an operating condition of the positioning information satellite;

an external input step that outputs command information instructing the reception unit to receive in response to external input;

a reception timing configuration step that sets the start time of reception by the reception unit so that the satellite signal is received immediately or at a predetermined timing based on command information from the external input unit;

a step that starts reception by the reception unit from the moment the start timing arrives;

a time adjustment information storage step that stores the satellite-time-related information of the satellite signal received by the reception unit as time adjustment information; and

a step that corrects the generated time information based on the time adjustment information.