POSITION CALCULATION METHOD AND POSITION CALCULATION APPARATUS

• US 20110001663A1
• Filed: 07/01/2010
• Published: 01/06/2011
• Est. Priority Date: 07/02/2009
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Onda, Kenji, Mizuochi, Shunichi, Uchida, Shuji, Sanjay, Rama, Anand, Kumar, Sugimoto, Takuya
• Granted Patent: US 8,593,341 B2
• Time in Patent Office: Days
• US Class Current: 342/357.23
• CPC Class Codes: G01S 19/40 Correcting position, velocity or attitude
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled

Abstract

A position calculation method and apparatus are described. The position calculation apparatus may include an inertial measurement unit and be configured to be coupled with at least one sensor unit for detecting a physical event for use in position calculation. The presence of and type sensor unit may identified, and the position processing to be undertaken may depend on this identification.

Claims

1. A position calculation method executed by a position calculation apparatus, the method comprising:

determining whether a sensor unit for detecting a physical event for use in position calculation is mounted on the position calculation apparatus;

identifying, when the determining step indicates the sensor unit is mounted on the position calculation apparatus, a type of sensor unit mounted on the position calculation apparatus; and

calculating, when the determining step indicates the sensor unit is mounted on the position calculation apparatus, a position using an output of an inertial measurement unit integrated with the position calculation apparatus and an output of the sensor unit in accordance with the identified type of the sensor unit.

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

calculating, when the determining step indicates the sensor unit is not mounted on the position calculation apparatus, a position using an output of the inertial measurement unit integrated with the position calculation apparatus

3. The method according to claim 1, further comprising:

receiving calibration standard type information representing the type of calibration standard information for calibration of the sensor unit;

calculating calibration standard information responsive to the calibration standard type information and the output of the inertial measurement unit; and

calibrating the sensor unit by using the calibration standard information.

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

calculating the position by filter processing using the output of the sensor unit.

5. The method according to claim 1, further comprising:

determining that the sensor unit is a satellite position calculation unit configured to calculate a position by using a satellite signal from a position calculation satellite;

predicting an initialized position by using a value other than a position calculated by the satellite position calculation unit, and

correcting the initialized position based at least in part on a position calculated by the satellite position calculation unit.

6. The method according to claim 5, further comprising:

acquiring information representing a time interval at which the satellite position calculation unit calculates a position,

wherein the prediction comprises repeatedly predicting a position during the time interval, and the correction comprises correcting the predicted position at the time interval.

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

determining that the sensor unit is a direction sensor unit for measuring a direction of the sensor unit.

8. The method according to claim 7, further comprising:

receiving the measured direction of the sensor unit; and

calculating an angular velocity using the received measured direction and a previously acquired direction.

9. The method according to claim 1, wherein the identifying the type of sensor unit comprises:

identifying two or more types of sensor units mounted on the position calculation apparatus.

10. The method according to claim 9, wherein the two or more types of sensor units include a first type comprising a satellite position calculation unit and a second type comprising a direction sensor unit.

11. A position calculation apparatus comprising:

an inertial measurement unit;

a mounting slot configured to be mountably coupled with a sensor unit for detecting a physical event for use in position calculation;

a slot control section, communicatively coupled with the mounting slot, and configured to;

determine whether the sensor unit is mounted on the mounting slot; and

identify a type of the sensor unit when it is determined that the sensor unit is mounted on the mounting slot; and

a position calculation section, communicatively coupled with the inertial measurement unit and the slot control section, and configured to calculate, when the determining step indicates the sensor unit is mounted on the mounting slot, a position using an output of the inertial measurement unit and an output of the sensor unit in accordance with the identified type of the sensor unit.

12. The apparatus according to claim 11, wherein the position calculation section is further configured to:

calculate, when the slot control section indicates the sensor unit is not mounted on the position calculation apparatus, a position using an output of the inertial measurement unit integrated with the position calculation apparatus.

13. The apparatus according to claim 11, wherein the slot control section is configured to:

acquire calibration standard type information representing the type of calibration standard information for calibration of the sensor unit;

calculate calibration standard information responsive to the calibration standard type information and the output of the inertial measurement unit; and

output the calibration standard information to the sensor unit.

14. The apparatus according to claim 11, wherein the position calculation section is further configured to:

calculate the position by filter processing using the output of the sensor unit.

15. The apparatus according to claim 11, wherein,

the slot control section is configured to determine that the sensor unit is a satellite position calculation unit configured to calculate a position by using a satellite signal from a position calculation satellite;

and

the satellite position calculation unit is configured to;

predict an initialized position by using a value other than a position calculated by the satellite position calculation unit, and

correct the initialized position based at least in part on a position calculated by the satellite position calculation unit.

16. The apparatus according to claim 15, wherein,

the slot control section is configured to acquire information representing a time interval at which the satellite position calculation unit calculates a position, and

wherein the prediction comprises repeatedly predicting a position during the time interval, and the correction comprises correcting the predicted position at the time interval.

17. The apparatus according to claim 11, wherein the slot control section is configured to determine that the sensor unit is a direction sensor unit to measure a direction of the sensor unit.

18. The apparatus according to claim 17, wherein the slot control section is configured to:

receive the measured direction of the sensor unit; and

calculate an angular velocity using the received measured direction and a previously acquired direction.

19. The apparatus according to claim 11, wherein the slot control section is configured to identify two or more types of sensor units mounted on the position calculation apparatus.

20. The apparatus according to claim 19, wherein the two or more types of sensor units include a first type comprising a satellite position calculation unit and a second type comprising a direction sensor unit.