Mobile communication apparatus and position detection method thereof

• US 20020175854A1
• Filed: 04/19/2002
• Published: 11/28/2002
• Est. Priority Date: 04/20/2001
• Status: Active Grant

• Current Assignee: Pioneer Corporation
• Original Assignee: Pioneer Corporation
• Inventors: Shioda, Takehiko, Nohara, Manabu
• Granted Patent: US 6,798,376 B2
• Time in Patent Office: Days
• US Class Current: 342/357.1
• CPC Class Codes: G01S 19/48 by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

When position measurement accuracy of the present position which the base station distance and position measurement part measures from radio waves coming from base stations is not good, a GPS distance and position measurement part measures the present position from radio waves coming from GPS satellites. When position measurement accuracy of the present position obtained by the GPS distance and position measurement part is not good, a position measurement accuracy analysis part compounds the present position obtained by the base station distance and position measurement part with the present position obtained by the GPS distance and position measurement part, and calculates a new position within a range of overlap between a position measurement error of the present position obtained by the base station distance and position measurement part and a position measurement error of the present position obtained by the GPS distance and position measurement part.

Claims

1. A mobile communication apparatus comprising:

a base station distance and position measurement part which measures first propagation distances of radio waves coming from base stations and measures a first present position of the mobile communication apparatus from the first propagation distances;

a GPS distance and position measurement part which measures second propagation distances of radio waves coming from GPS satellites and measures a second present position of the mobile communication apparatus from second propagation distances; and

a position measurement accuracy analysis part which decides one of the first present position and the second present position to be a true present position of the mobile communication apparatus,

wherein the base station distance and position measurement part decides a first position measurement error of the first present position;

the position measurement accuracy analysis part compares the first position measurement error of the first present position with a first predetermined criterion; and

when the position measurement accuracy analysis part decides that the position measurement error exceeds the first predetermined criterion, the GPS distance and position measurement part measures the second propagation distances and the second present position; and

the position measurement accuracy analysis part decides that the second present position is adopted as the true present position of the mobile communication apparatus.

2. The mobile communication apparatus as defined in claim 1, wherein the GPS distance and position measurement part decides the second position measurement error of the second present position;

the position measurement accuracy analysis part compares the second position measurement error with the second predetermined criterion;

when the position measurement accuracy analysis part decides that the second position measurement error exceeds the second predetermined criterion, the position measurement accuracy analysis part calculates a third present position within a range of overlap between the first position measurement error and the second position measurement error; and

the position measurement accuracy analysis part decides that the third present position is adopted as the true present position of the mobile communication apparatus.

3. The mobile communication apparatus as defined in claim 1, further comprises a controller which stops an operation of the GPS distance and position measurement part at the time of the distance measurement and position measurement by the base station distance and position measurement part.

4. The mobile communication apparatus as defined in claim 2, further comprises a controller which stops an operation of the GPS distance and position measurement part at the time of the distance measurement and position measurement by the base station distance and position measurement part.

5. A position detection method for detecting a position of a mobile communication apparatus, comprising the steps of:

measuring a first present position of the mobile communication apparatus from radio waves coming from base stations and a first position measurement error;

comparing the first position measurement error with a first predetermined criterion; and

measuring a second present position of the mobile communication apparatus from radio waves coming from GPS satellites when the first position measurement error exceeds the first predetermined criterion.

6. The position detection method as defined in claim 5, further comprising:

measuring a second position measurement error; and

comparing the second position measurement error with a second predetermined criterion; and

calculating a third present position within a range of overlap between the first position measurement error and the second position measurement error when the second position measurement error exceeds the second predetermined criterion.

7. A mobile communication apparatus comprising:

a first receiver which receives first radio waves coming from base stations;

a second receiver which receives second radio waves coming form GPS satellites;

a first calculator which calculates a first position of the mobile communication apparatus and a first error of the first position from the first radio waves;

an analyzer which compares the first error with a first predetermined criterion; and

a second calculator which calculates a second position of the mobile communication apparatus and a second error of the second position from the second radio waves,

wherein the analyzer decides the second present position to be a true present position of the mobile communication apparatus.

8. The mobile communication apparatus as defined in claim 7, wherein the second calculator is turned on to calculate the second propagation distances and the second position when the analyzer determines that the first error exceeds the first predetermined criterion.

9. The mobile communication apparatus as defined in claim 7, wherein the analyzer calculates the third position when the analyzer compares the second error with a second predetermined criterion and decides that the second error exceeds the second predetermined criterion;

and

the analyzer decides the third position to be the true present position of the mobile communication apparatus.

10. The mobile communication apparatus as defined in claim 9, wherein the analyzer calculates a third position within a range of overlap between the first error and the second error.

11. A mobile communication apparatus comprising:

a first receiver which receives first radio waves coming from base stations;

a second receiver which receives second radio waves coming from GPS satellites;

a first calculator which calculates a first position of the mobile communication apparatus and a first error of the first position based on the first radio waves; and

a second calculator which calculates a second position of the mobile communication apparatus and a second error of the second position based on the second radio waves, wherein an analyzer calculates a third position based on the first position including first error and the second position including a second error, and decides the third position to be a true present position of the mobile communication apparatus.

12. The mobile communication apparatus as defined in claim 11, wherein the analyzer calculates the third position within a range of overlap between the first error and the second error.