Mobile communication terminal and method having calculated terminal position uncertainty check function

• US 6,947,729 B2
• Filed: 09/06/2002
• Issued: 09/20/2005
• Est. Priority Date: 09/07/2001
• Status: Expired due to Term

• Current Assignee: Beijing Xiaomi Mobile Software Co., Ltd. (Xiaomi Corp.)
• Original Assignee: DENSO Corporation
• Inventors: Takeuchi, Toshihiro, Shamoto, Michio, Ogino, Hiroyasu, Oda, Kyoji, Shintai, Tatsuya, Hayashida, Atsushi
• Primary Examiner(s): Young, W. R.
• Assistant Examiner(s): Phuong, Dai
• Application Number:
  US10/235,937
• Publication Number:
  US 20030050077A1
• Time in Patent Office: 1,110 Days
• Field of Search: 455/456.1, 455/456.3, 455/456.6, 455/457, 455/414.4, 455/414.2, 455/404.2, 701/213
• US Class Current: 455/414.2
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/393 Trajectory determination or predictive tracking, e.g. Kalman filtering
• CPC Class Codes: G01S 19/396 Determining accuracy or reliability of position or pseudorange measurements
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial

Abstract

A mobile communication terminal stores positioning information including global positioning system signals and base station information required by a position server in a communication network to calculate the terminal position. When the position server calculates the terminal position based on these positioning unit information, the position information is not reported to the user if the indefinite information equivalent to a positioning error contained in the average value calculated for the terminal position information exceeds a predetermined threshold value. When the average processing count exceeds a maximum positioning count, that average value is reported to the user.

Claims

1. A mobile communication terminal for communicating with base stations forming a communication network comprising:

means for collecting at least positioning information containing base station information of the base stations;

means for sending the positioning information on the communication network as information required for calculating a terminal position;

means for acquiring terminal position information calculated for the communication network based on the positioning information;

means for checking whether uncertain information equivalent to a position calculation error contained in the terminal position information is within a predetermined threshold; and

means for controlling an output of the terminal position information to a terminal user, the controlling means enabling and disabling the output of the terminal position information when the uncertain information is less than and more than the predetermined threshold, respectively, and causing the collecting means and the sending means to collect and send the positioning information again to the communication network for positioning calculation when the uncertain information is more than the predetermined threshold.

2. A mobile communication terminal according to claim 1, the controlling means includes:

means for storing the terminal position information when the uncertain information is more than the predetermined threshold; and

calculating an average of the stored terminal position information so that the calculated average is output.

3. A mobile communication terminal according to claim 1, further comprising:

means for receiving a GPS signal from a GPS satellite,

wherein the sending means sends the GPS signal as a part of the positioning information required for calculating the terminal position.

4. A mobile communication terminal according to claim 1, wherein the sending means sends the positioning information to a position calculating server through the communication network so that the terminal position is calculate by the position calculation server, and the acquiring means acquires the terminal position information through the communication network.

5. A mobile communication terminal according to claim 1, wherein the uncertain information is calculated as a radius of a circle which circumscribes an area of overlap of a plurality of circles, assuming that the mobile communication terminal is within the area.

6. A mobile communication terminal according to claim 1, wherein the uncertain information is calculated as a distance largest from a center coordinate of an area of overlap of a plurality of circles.

7. A computer readable medium having a computer program including instructions for communicating with base stations forming a communication network, wherein the program comprises steps of:

collecting at least positioning information containing base station information on the base stations, as information required for calculating the terminal position;

sending the positioning information to the communication network for positioning calculation;

acquiring terminal position information calculated on the communication network;

comparing uncertainty information equivalent to a position calculation error contained in the terminal position information with a predetermined threshold;

outputting the acquired terminal position information to a user only when the uncertainty information is less than the predetermined threshold; and

collecting and sending the positioning information to the communication network for positioning calculation, without outputting the acquired terminal position to the terminal user when the uncertain information is more than the predetermined threshold.

8. A computer readable medium having a computer program, according to claim 7, the program further comprising a step of:

storing the terminal position information which includes the uncertain information in more than the predetermined threshold;

counting the number of times of storing the acquired terminal position information; and

outputting to the terminal user an average value of the stored terminal position information, when the number of the stored position information reaches a predetermined reference.

9. A computer readable medium having a computer program, according to claim 7, the program further comprising a step of:

acquiring a GPS signal from a GPS satellite,

wherein the sending step sends the acquired GPS signal with the positioning information required for calculating the terminal position.

10. A method of determining a mobile terminal position comprising steps of:

receiving a positioning calculation request input to a mobile terminal;

selecting a PN code of a base station as a reference station from a plurality of neighbor base stations provided away from the mobile terminal by searching the neighbor base stations based on a neighbor list, the reference station being defined to be one that has a minimum signal delay;

sending PN codes and signal delays of the neighbor base stations to a position server provided away from the mobile terminal after storing the PN codes and the signal delays;

receiving assist information from the position server;

acquiring a GPS signal of a GPS satellite and neighbor base station information based on the assist information;

sending the GPS signal and the neighbor base station information to the position server so that a mobile terminal position is calculated by the position server;

receiving mobile terminal position information with uncertain information from the position server;

checking whether the uncertain information is more than or less than a predetermined threshold;

indicating the mobile terminal position information when the uncertain information is less than the predetermined threshold; and

repeating all of the above steps when the uncertain information is more than the predetermined threshold.

11. A method according to claim 10 further comprising steps of:

counting the number of repetition of the repeating step; and

calculating and indicating an average of the mobile terminal position information when the number of repetition reaches a predetermined reference.