Mobile terminal, system and method

• US 8,965,684 B2
• Filed: 11/28/2011
• Issued: 02/24/2015
• Est. Priority Date: 12/02/2010
• Status: Expired due to Fees

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Takahashi, Makoto
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): SMITH-STEWART, DEMETRA R
• Application Number:
  US13/880,988
• Publication Number:
  US 20130211709A1
• Time in Patent Office: 1,184 Days
• US Class Current: 701/417
• CPC Class Codes: G01C 21/005 with correlation of navigation data from several sources, e.g. map or contour matching G01C21/30 takes precedence
• CPC Class Codes: G01C 21/188 for accumulated errors, e.g. by coupling inertial systems with absolute positioning systems
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G01S 19/40 Correcting position, velocity or attitude
• CPC Class Codes: G08G 1/005 including pedestrian guidance indicator
• CPC Class Codes: G08G 1/096827 where the route is computed onboard

Abstract

The present invention pertains to a mobile terminal having an autonomous navigation function, said mobile terminal comprising: a map application which performs map matching on the current position of the mobile terminal on a route to a destination; a measurement unit which detects the movement of the mobile terminal, and which provides sensor information representing the number of steps and travel direction; a position calculation unit which determines the current position of the mobile terminal; a travel direction correction unit which, when it has been estimated that a user is walking straight by determining whether the amount of change of the user'"'"'s travel direction is within a prescribed range in a prescribed period, corrects the user'"'"'s travel direction according to the orientation of the straight parts when the user is walking straight on the route; and a current position correction unit which, on the basis of the corrected travel direction and the starting time and starting point when walking straight, recalculates the current position of the mobile terminal from the starting point, and corrects the current position of the mobile terminal according to the recalculated current position.

Claims

1. A mobile terminal having an autonomous navigation function, comprising:

circuitry configured to

perform map matching of a current position of the mobile terminal onto a route from a departure point to a destination point of a user of the mobile terminal in map information;

detect movement of the mobile terminal and provide sensor information indicative of a number of steps and a travelling direction of the user;

determine the current position of the mobile terminal based on the number of steps and the travelling direction of the user in the sensor information;

estimate whether the user is in a straight walking state by determining whether a change amount of the travelling direction of the user in the sensor information is within a predefined range for a predefined time period;

compare, if it is estimated that the user is in the straight walking state, the travelling direction correction unit of the user with a direction of a corresponding straight portion of the route in the map information from the departure point to the destination point of the user in the straight walking state;

correct the travelling direction of the user based on the comparison;

recalculate the current position of the mobile terminal from a start point based on the corrected travelling direction as well as a start time point and the start point of the straight walking state; and

correct the current position of the mobile terminal with the recalculated current position.

2. The mobile terminal as claimed in claim 1, wherein when the current position of the mobile terminal deviates from the route by a predefined distance, the circuitry is configured to perform the map matching by matching the current position of the mobile terminal onto the route.

3. The mobile terminal as claimed in claim 2, wherein when it is estimated that the user is in the straight walking state, the circuitry is configured to calculate a direction between two points map-matched previously onto the straight portion of the route and correct the travelling direction of the user with the calculated direction.

4. The mobile terminal as claimed in claim 1, wherein the circuitry is configured to estimate whether the user is in the straight walking state by determining whether a standard deviation of measurement values of the travelling direction of the user for the predefined time period is less than or equal to a predefined threshold.

5. The mobile terminal as claimed in claim 1, wherein the circuitry is configured to estimate whether the user is in the straight walking state by determining whether a change amount of the travelling direction of the user in the sensor information is within a predefined range for a predefined time period as well as determining whether the user has walked by greater than or equal to a predefined distance for the predefined time period based on the number of steps of the user in the sensor information.

6. The mobile terminal as claimed in claim 1, wherein the circuitry is configured to recalculate the current position of the mobile terminal from the start point by calculating a movement amount of the mobile terminal from the start time point to a current time point based on the number of steps of the user from the start time point to the current time point and the corrected travelling direction and adding the calculated movement amount to the start point.

7. A system, comprising:

a mobile terminal having an autonomous navigation function; and

a server communicatively connected to the mobile terminal,

the server performing map matching of a current position of the mobile terminal onto a route from a departure point to a destination point of a user of the mobile terminal in map information and indicating the position map-matched onto the route to the mobile terminal,

the mobile terminal comprising;

circuitry configured to

detect movement of the mobile terminal and provide sensor information indicative of a number of steps and a travelling direction of the user;

determine the current position of the mobile terminal based on the number of steps and the travelling direction of the user in the sensor information;

estimate whether the user is in a straight walking state by determining whether a change amount of the travelling direction of the user in the sensor information is within a predefined range for a predefined time period;

compare, if it is estimated that the user is in the straight walking state, the travelling direction of the user with a direction of a corresponding straight portion of the route in the map information from the departure point to the destination point of the user in the straight walking state;

correct the travelling direction of the user based on the comparison;

recalculate the current position of the mobile terminal from a start point based on the corrected travelling direction as well as a start time point and the start point of the straight walking state; and

correct the current position of the mobile terminal with the recalculated current position.

8. A method for use in a mobile terminal having an autonomous navigation function, comprising:

performing map matching of a current position of the mobile terminal onto a route from a departure point to a destination point of a user of the mobile terminal in map information;

detecting movement of the mobile terminal and providing sensor information indicative of a number of steps and a travelling direction of the user;

determining the current position of the mobile terminal based on the number of steps and the travelling direction of the user in the sensor information;

estimating whether the user is in a straight walking state by determining whether a change amount of the travelling direction of the user in the sensor information is within a predefined range for a predefined time period;

comparing, if it is estimated that the user is in the straight walking state, the travelling direction of the user with a direction of a corresponding straight portion of the route in the map information from the departure point to the destination point of the user in the straight walking state;

correcting the travelling direction of the user based on the comparison;

recalculating the current position of the mobile terminal from a start point based on the corrected travelling direction as well as a start time point and the start point of the straight walking state; and

correcting the current position of the mobile terminal with the recalculated current position.