Time correction device, timepiece having a time correction device, and time correction method

• US 7,474,594 B2
• Filed: 07/13/2007
• Issued: 01/06/2009
• Est. Priority Date: 07/31/2006
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Fujisawa, Teruhiko, Urano, Osamu, Honda, Katsuyuki, Matsuzaki, Jun
• Primary Examiner(s): Miska; Vit W
• Application Number:
  US11/777,898
• Publication Number:
  US 20080175105A1
• Time in Patent Office: 543 Days
• Field of Search: 368/10, 368/46, 368/47, 368/52, 342/352, 342/357.01, 342/357.08, 342/357.12, 342/357.15, 455/502
• US Class Current: 368/47
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: G01S 19/23 Testing, monitoring, correcting or calibrating of receiver elements
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/35 Constructional details or hardware or software details of the signal processing chain
• CPC Class Codes: G04R 20/04 Tuning or receiving; Circuits therefor

Abstract

A time correction device including a positioning unit that receives signals from positioning information satellites orbiting the Earth and determines the position of the positioning unit; 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 that corrects the time information based on the time correction information; a time correction basis information storage unit that stores time correction basis information, which is basis information for generating the time correction information; a time correction information generating unit that generates the time correction information based on the time correction basis information; and a selection information storage unit for storing selection information. The time correction basis information includes plural-satellite-referenced time correction basis information; single-satellite-referenced time correction basis information and partial-satellite-signal-referenced time correction basis information. The selection information is used by the time correction information generating unit to select from the time correction basis information and apply the plural-satellite-referenced time correction basis information, the single-satellite-referenced time correction basis information, or the partial-satellite-signal-referenced time correction basis information.

Claims

1. A time correction device comprising:

a positioning unit that receives signals from positioning information satellites orbiting the Earth and determines the position of the positioning unit;

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 that corrects the time information based on the time correction information;

a time correction basis information storage unit that stores time correction basis information, which is basis information for generating the time correction information;

a time correction information generating unit that generates the time correction information based on the time correction basis information; and

a selection information storage unit for storing selection information;

wherein the time correction basis information includes

plural-satellite-referenced time correction basis information that is the basis information for generating the time correction information based on signals from a plurality of positioning information satellites;

single-satellite-referenced time correction basis information that is the basis information for generating the time correction information based on signals from a single positioning information satellite using positioning information acquired when the time correction information generating unit generates the time correction information based on the plural-satellite-referenced time correction basis information; and

partial-satellite-signal-referenced time correction basis information that is the basis information for generating the time correction information based on a time-related signal in the signals received from a single positioning information satellite using time difference information acquired when the time correction information generating unit generates the time correction information based on the single-satellite-referenced time correction basis information; and

the selection information is used by the time correction information generating unit to select from the time correction basis information and apply the plural-satellite-referenced time correction basis information, the single-satellite-referenced time correction basis information, or the partial-satellite-signal-referenced time correction basis information.

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

the plural positioning information satellites are four GPS (Global Positioning System) satellites;

the plural-satellite-referenced time correction basis information is the basis information for generating

the true transmission delay time and the position information of the positioning information satellites that are calculated based on an actually measured transmission delay time from transmission to reception of the signals from the four GPS satellites, and

the transmission delay time that is the time produced by the time information generating unit; and

the time correction information is the difference between the true transmission delay time and the measured transmission delay time.

3. The time correction device described in claim 2, wherein:

the single-satellite-referenced time correction basis information is the basis information for generating

the true transmission delay time by a calculation based on a satellite distance that is determined from a pseudo-current position and the GPS satellite position information that is identified from the GPS satellite orbital information,

where the position information that is the positioning information of the time correction device is used as the pseudo-current position, and

the transmission delay time that is the time produced by the time information generating unit.

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

the time difference information used to determine the partial-satellite-signal-referenced time correction basis information includes an average of the transmission delay times acquired when the time correction information generating unit applies the single-satellite-referenced time correction basis information, and an average of the difference information;

the time-related signal is GPS time information from the GPS satellite; and

the GPS time information, the average transmission delay time, and the average difference information are the basis information of the time correction information.

5. A timekeeping device having a time correction device comprising:

a positioning unit that receives signals from positioning information satellites orbiting the Earth and determines the position of the positioning unit;

a time information generating unit that generates time information;

a time correction information storage unit that stores time correction information for correcting the time information;

a time information correction unit that corrects the time information based on the time correction information;

a time correction basis information storage unit that stores time correction basis information, which is basis information for generating the time correction information;

a time correction information generating unit that generates the time correction information based on the time correction basis information; and

a selection information storage unit for storing selection information;

wherein the time correction basis information includes

plural-satellite-referenced time correction basis information that is the basis information for generating the time correction information based on signals from a plurality of positioning information satellites;

single-satellite-referenced time correction basis information that is the basis information for generating the time correction information based on signals from a single positioning information satellite using positioning information acquired when the time correction information generating unit generates the time correction information based on the plural-satellite-referenced time correction basis information; and

partial-satellite-signal-referenced time correction basis information that is the basis information for generating the time correction information based on a time-related signal in the signals received from a single positioning information satellite using time difference information acquired when the time correction information generating unit generates the time correction information based on the single-satellite-referenced time correction basis information; and

the selection information is used by the time correction information generating unit to select from the time correction basis information and apply the plural-satellite-referenced time correction basis information, the single-satellite-referenced time correction basis information, or the partial-satellite-signal-referenced time correction basis information.

6. A time correction method of correcting the time information of a time information generating unit that generates time information based on time correction information, comprising:

a first time correction information generating step of a time correction information generating unit producing the time correction information based on plural-satellite-referenced time correction basis information that is the basis information for generating the time correction information based on signals received by a positioning unit from a plurality of positioning information satellites orbiting the Earth;

a first time information correcting step of a time information correction unit correcting the time information of the time information generating unit based on the time correction information generated by the first time correction information generating step;

a second time correction information generating step of the time correction information generating unit producing the time correction information based on single-satellite-referenced time correction basis information that is the basis information for generating the time correction information based on signals from a single positioning information satellite using positioning information acquired by the positioning unit in the first time correction information generating step;

a second time information correcting step of the time information correction unit correcting the time information of the time information generating unit based on the time correction information generated by the second time correction information generating step;

a third time correction information generating step of the time correction information generating unit producing the time correction information based on partial-satellite-signal-referenced time correction basis information that is the basis information for generating the time correction information based on a time-related signal in the signals received from a single positioning information satellite using time difference information acquired in the second time correction information generating step; and

a third time information correcting step of the time information correction unit correcting the time information of the time information generating unit based on the time correction information produced in the third time correction information generating step.