POSITION CALCULATING METHOD AND POSITION CALCULATING DEVICE

• US 20100117901A1
• Filed: 11/05/2009
• Published: 05/13/2010
• Est. Priority Date: 11/11/2008
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: UCHIDA, Shuji
• Granted Patent: US 8,154,447 B2
• Time in Patent Office: Days
• US Class Current: 342/357.670
• CPC Class Codes: G01S 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver

Abstract

A position calculating method includes: determining a positioning satellite used for position calculation on the basis of at least reliability of satellite orbits in a prediction target period corresponding to a position calculation point, the reliability of satellite orbits being set in long-term predicted orbit data in which satellite orbits of positioning satellites and reliability of the satellite orbits are associated for each prediction target period; and calculating a position on the basis of a positioning signal received from the determined positioning satellite.

Claims

1. A position calculating method comprising:

determining a positioning satellite used for position calculation on the basis of at least reliability of satellite orbits in a prediction target period corresponding to a position calculation point, the reliability of satellite orbits being set in long-term predicted orbit data in which satellite orbits of positioning satellites and reliability of the satellite orbits are associated for each prediction target period; and

calculating a position on the basis of a positioning signal received from the determined positioning satellite.

2. The position calculating method according to claim 1, further comprising extracting a predetermined number of positioning satellites in order from one having highest reliability of a satellite orbit and determining a satellite used for the position calculation.

3. The position calculating method according to claim 1, further comprising deciding positioning satellites having equivalent reliability of the satellite orbit in the prediction target period corresponding to the position calculation point, wherein

the determining includes determining, taking into account reliability of a satellite orbit in a prediction target period before or after the prediction target period corresponding to the position calculation point, whether the positioning satellites having equivalent reliability of the satellite orbit should be used for the position calculation.

4. The position calculating method according to claim 1, further comprising:

deciding a reception environment for the positioning signal; and

determining a satellite used for the position calculation on the basis of the decided reception environment.

5. The position calculating method according to claim 4, further comprising:

variably setting, according to the decided reception environment, at least a determination target period including the prediction target period corresponding to the position calculation point in the prediction target period included in the long-term predicted orbit data; and

determining a satellite used for the position calculation on the basis of reliability in the determination target period.

6. A position calculating device comprising:

a determining unit that determines a positioning satellite used for position calculation on the basis of at least reliability of satellite orbits in a prediction target period corresponding to a position calculation point, the reliability of satellite orbits being set in long-term predicted orbit data in which satellite orbits of positioning satellites and reliability of the satellite orbits are associated for each prediction target period; and

a position calculating unit that calculates a position on the basis of a positioning signal received from the determined positioning satellite.