Navigation Apparatus and Position Detection Method

• US 20080114545A1
• Filed: 08/29/2007
• Published: 05/15/2008
• Est. Priority Date: 08/31/2006
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Suga, Yoshitaka, Takaoka, Tomohisa
• Granted Patent: US 7,945,384 B2
• Time in Patent Office: Days
• US Class Current: 701/220
• CPC Class Codes: G01C 21/265 constructional aspects of navigation devices, e.g. housings, mountings, displays G01C21/3688 takes precedence
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments

Abstract

A navigation apparatus includes: a main unit to be attached to a mobile object through a base section, the main unit detecting a current position of the mobile object based on positioning information; a section that calculates acceleration applied to the mobile object based on the mobile object'"'"'s speed; an acceleration sensor that observes acceleration applied to the main unit; a section that calculates an attachment inclination of the acceleration sensor with respect to the mobile object; a section that estimates, while the positioning information is not being supplied, a speed and position of the mobile object; a section that detects whether the main unit is mounted on the base section; and a section that forces the above section to stop estimating the speed when the main unit is not mounted on the base section.

Claims

1. A navigation apparatus comprising:

a main unit to be attached to a mobile object through a predetermined base section on which the main unit is mounted, the main unit detecting a current position of the mobile object based on positioning information supplied from predetermined positioning means;

acceleration calculation means for calculating acceleration applied to the mobile object based on the mobile object'"'"'s speed calculated based on the positioning information;

an acceleration sensor for observing acceleration applied to the main unit;

attachment inclination calculation means for calculating an attachment inclination of the acceleration sensor with respect to the mobile object, based on the mobile object'"'"'s acceleration and the observed acceleration;

speed estimate means for estimating, while the positioning information is not being supplied, a speed and position of the mobile object, based on the observed acceleration and the attachment inclination;

a mounting detection section for detecting whether the main unit is mounted on the base section; and

speed estimate control means for forcing the speed estimate means to stop estimating the speed when the mounting detection section detects that the main unit is not mounted on the base section.

2. The navigation apparatus according to claim 1, wherein

the speed estimate control means regards the latest speed estimated by the speed estimate means as the current speed when the positioning information is not being supplied after the mounting detection section detects that the main unit is not mounted on the base section.

3. The navigation apparatus according to claim 1, wherein

the speed estimate control means regards the latest speed calculated from the positioning information as the current speed when the positioning information is not being supplied after the mounting detection section detects that the main unit is not mounted on the base section.

4. The navigation apparatus according to claim 1, wherein

the attachment inclination calculation means stops calculating the attachment inclination when the mounting detection section detects that the main unit is not mounted on the base section.

5. The navigation apparatus according to claim 1, wherein

the attachment inclination calculation means recursively calculates the attachment inclination by repeating an arithmetic process based on a predetermined initial value, and calculates, when the main unit is mounted on the base section again, the attachment inclination again by using the previous attachment inclination, calculated before the main unit was dismounted from the base section, as the initial value.

6. The navigation apparatus according to claim 1, further comprising

acceleration calculation means for calculating the mobile object'"'"'s acceleration in the direction of the mobile object'"'"'s motion, based on the mobile object'"'"'s speed calculated from the positioning information, and horizontal acceleration whose direction is perpendicular to the mobile object'"'"'s motion, based on the mobile object'"'"'s speed and direction calculated from the positioning information, wherein

the acceleration sensor observes motion acceleration of the mobile object and gravity acceleration;

and

the attachment inclination calculation means calculates, based on a road'"'"'s altitude difference calculated based on an atmospheric pressure value from a predetermined barometric sensor and a travel distance corresponding to the mobile object'"'"'s speed, an inclination angle of the road in the direction of the motion, and then calculates the attachment inclination by using a multidimensional function formula including the acceleration in the direction of the motion, the horizontal acceleration, values observed by the acceleration sensor and the inclination angle, the observed values including the motion acceleration and the gravity acceleration.

7. A position detection method comprising:

a detection step of detecting a current position of a main unit attached to a mobile object through a base section on which the main unit is mounted, based on the positioning information supplied from predetermined positioning means;

an acceleration calculation step of calculating acceleration applied to the mobile object based on the mobile object'"'"'s speed calculated based on the positioning information;

an acceleration observation step of observing, by using an acceleration sensor, acceleration applied to the main unit;

an attachment inclination calculation step of calculating an attachment inclination of the acceleration sensor with respect to the mobile object, based on the mobile object'"'"'s acceleration and the observed acceleration;

speed estimate step of estimating, while the positioning information is not being supplied, a speed and position of the mobile object, based on the observed acceleration and the attachment inclination;

a mounting detection step of detecting whether the main unit is mounted on the base section; and

a speed estimate control step of forcing the speed estimate step to stop estimating the speed when the mounting detection step detects that the main unit is not mounted on the base section.

8. The position detection method according to claim 7, wherein

the speed estimate control step regards the latest speed estimated by the speed estimate step as the current speed when the positioning information is not being supplied after the mounting detection step detects that the main unit is not mounted on the base section.

9. The position detection method according to claim 7, wherein

the speed estimate control step regards the latest speed calculated from the positioning information as the current speed when the positioning information is not being supplied after the mounting detection step detects that the main unit is not mounted on the base section.

10. The position detection method according to claim 7, wherein

the attachment inclination calculation step stops calculating the attachment inclination when the mounting detection step detects that the main unit is not mounted on the base section.

11. The position detection method according to claim 7, wherein

the attachment inclination calculation step recursively calculates the attachment inclination by repeating an arithmetic process based on a predetermined initial value, and calculates, when the main unit is mounted on the base section again, the attachment inclination again by using the previous attachment inclination, calculated before the main unit was dismounted from the base section, as the initial value.

12. The position detection method according to claim 7, further comprising

an acceleration calculation step of calculating the mobile object'"'"'s acceleration in the direction of the mobile object'"'"'s motion, based on the mobile object'"'"'s speed calculated from the positioning information, and horizontal acceleration whose direction is perpendicular to the mobile object'"'"'s motion, based on the mobile object'"'"'s speed and direction calculated from the positioning information, wherein

the acceleration sensor observes motion acceleration of the mobile object and gravity acceleration;

and

the attachment inclination calculation step calculates, based on a road'"'"'s altitude difference calculated based on an atmospheric pressure value from a predetermined barometric sensor and a travel distance corresponding to the mobile object'"'"'s speed, an inclination angle of the road in the direction of the motion, and then calculates the attachment inclination by using a multidimensional function formula including the acceleration in the direction of the motion, the horizontal acceleration, values observed by the acceleration sensor and the inclination angle, the observed values including the motion acceleration and the gravity acceleration.

13. A navigation apparatus comprising:

a main unit to be attached to a mobile object through a predetermined base section on which the main unit is mounted, the main unit detecting a current position of the mobile object based on positioning information supplied from predetermined positioning means;

an acceleration calculation section that calculates acceleration applied to the mobile object based on the mobile object'"'"'s speed calculated based on the positioning information;

an acceleration sensor that observes acceleration applied to the main unit;

an attachment inclination calculation section that calculates an attachment inclination of the acceleration sensor with respect to the mobile object, based on the mobile object'"'"'s acceleration and the observed acceleration;

a speed estimate section that estimates, while the positioning information is not being supplied, a speed and position of the mobile object, based on the observed acceleration and the attachment inclination;

a mounting detection section that detects whether the main unit is mounted on the base section; and

a speed estimate control section that forces the speed estimate section to stop estimating the speed when the mounting detection section detects that the main unit is not mounted on the base section.