POSITION CALCULATING METHOD AND POSITION CALCULATING DEVICE

• US 20100159947A1
• Filed: 12/07/2009
• Published: 06/24/2010
• Est. Priority Date: 12/24/2008
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Imafuku, Shigeru
• Application Number:
  US12/631,928
• Publication Number:
  US 20100159947A1
• Time in Patent Office: Days
• US Class Current: 455/456.100
• CPC Class Codes: G01C 21/1654 with electromagnetic compass
• CPC Class Codes: G01C 21/188 for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled

Abstract

A position calculating method performed by a position calculating device carried with or mounted on a mobile body and moving with the mobile body, includes: receiving a positioning signal from a positioning satellite; calculating a position based on the received positioning signal; intermittently operating a sensor unit which detects moving condition of the mobile body in predetermined intermittent operation cycle; controlling the intermittent operation cycle according to the positioning signal receiving condition; calculating a position by executing predetermined inertial navigation calculation by using a detection result from the sensor unit operated in the intermittent operation cycle; and determining an output position by using the position calculated based on the positioning signal and the position calculated by the inertial navigation calculation.

Claims

1. A position calculating method performed by a position calculating device carried with or mounted on a mobile body and moving with the mobile body, comprising:

receiving a positioning signal from a positioning satellite;

calculating a position based on the received positioning signal;

intermittently operating a sensor unit which detects moving condition of the mobile body in predetermined intermittent operation cycle;

controlling the intermittent operation cycle according to the positioning signal receiving condition;

calculating a position by executing predetermined inertial navigation calculation by using a detection result from the sensor unit operated in the intermittent operation cycle; and

determining an output position by using the position calculated based on the positioning signal and the position calculated by the inertial navigation calculation.

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

predicting position and moving speed of the mobile body by performing prediction calculation based on Kalman filter theory;

predicting frequency of the positioning signal received at the predicted position by using the predicted position and moving speed; and

controlling the intermittent operation cycle based on the difference between the predicted frequency and the frequency of the received positioning signal.

3. The position calculating method according to claim 2, further comprising:

predicting phase of the positioning signal received at the predicted position by using the predicted position and moving speed; and

controlling the intermittent operation cycle based on the difference between the predicted phase and the phase of the received positioning signal.

4. The position calculating method according to claim 3, further comprising:

predicting the frequency and phase at predetermined intervals; and

controlling the intermittent operation cycle every time prediction is executed at the predetermined intervals.

5. The position calculating method according to claim 1, further comprising controlling the intermittent operation cycle based on history of the positioning signal receiving condition.

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

determining the moving condition of the mobile body from the positioning signal receiving condition; and

controlling the intermittent operation cycle based on the moving condition of the mobile body.

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

determining the positioning signal receiving environment from the positioning signal receiving condition; and

controlling the intermittent operation cycle based on the receiving environment.

8. A position calculating device carried with or mounted on a mobile body and moving with the mobile body, comprising:

a receiving unit which receives a positioning signal from a positioning satellite;

a first position calculating unit which calculates a position based on the received positioning signal;

a sensor operation control unit which intermittently operates a sensor unit for detecting moving condition of the mobile body in predetermined intermittent operation cycle;

an operation cycle control unit which controls the intermittent operation cycle according to the positioning signal receiving condition;

a second position calculating unit which calculates a position by executing predetermined inertial navigation calculation by using a detection result from the sensor unit operated in the intermittent operation cycle; and

a position determining unit which determines an output position by using the position calculated based on the positioning signal and the position calculated by the inertial navigation calculation.