GPS terminal, position measuring system, and map display method using the same

• US 6,334,090 B1
• Filed: 08/22/2000
• Issued: 12/25/2001
• Est. Priority Date: 08/24/1999
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: NEC Corporation
• Inventors: Fujii, Tomohiro
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Hernandez, Olga
• Application Number:
  US09/642,686
• Time in Patent Office: 490 Days
• Field of Search: 701/213, 701/208, 701/211, 701/212, 701/200, 731/78.R, 340/990, 340/991, 340/993
• US Class Current: 701/213
• CPC Class Codes: G01S 1/047 Displays or indicators G01S1/06 takes precedence
• CPC Class Codes: G01S 19/24 Acquisition or tracking or demodulation of signals transmitted by the system synchronisation aspects of direct sequence spread spectrum modulation H04B1/7073

Abstract

A GPS terminal includes a reception section, control section, and display section. The reception section is equipped with a GPS and receives radio signals transmitted from a plurality of artificial satellites. The control section recognizes the latitude/longitude data of the current position on the basis of the radio signals received by the reception section. The display section displays a map centered on the latitude/longitude data recognized by the control section. The reception section measures reception sensitivity with respect to the radio signals transmitted from the artificial satellites. The control section automatically changes the scale of the map displayed by the display section on the basis of the measurement result on the reception sensitivity in the reception section with respect to the radio signals. A position measuring system and map display method are also disclosed.

Claims

1. A GPS terminal comprising reception means, equipped with a GPS, for receiving radio signals transmitted from a plurality of artificial satellites, control means for recognizing latitude/longitude data of a current position on the basis of the radio signals received by said reception means, and display means for displaying a map centered on the latitude/longitude data recognized by said control means,

wherein said reception means measures reception sensitivity with respect to the radio signals transmitted from the plurality of artificial satellites, and

said control means automatically changes a scale of the map displayed by said display means on the basis of the measurement result on the reception sensitivity in said reception means with respect to the radio signals.

2. A terminal according to claim 1, wherein

said reception means measures reception sensitivity with respect to radio signals transmitted from the plurality of artificial satellites upon reception of a request to scale down the map displayed by said display means, and

said control means automatically changes the scale of the map displayed by said display means on the basis of the measurement result on the reception sensitivity in said reception means with respect to the radio signals.

5. A terminal according to any one of claims 1 to 4, wherein

said terminal further comprises storage means for storing a wide-area map in advance, and

said control means displays the wide-area map stored in said storage means upon changing a scale of the wide-area map on the basis of the measurement result in said reception means with respect to the radio signals.

7. A map display method using the GPS terminal defined in claim 5, comprising the steps of:

causing the reception means to measure reception sensitivity with respect to radio signals transmitted from the plurality of artificial satellites upon reception of a request to scale down the map displayed by the display means; and

causing the control means to display the wide-area map stored in the storage means upon changing the scale of the map on the basis of the measurement result on the reception sensitivity in the reception means with respect to the radio signals.

3. A GPS terminal comprising reception means, equipped with a GPS capable of network communication, for receiving radio signals transmitted from a plurality of artificial satellites, communication means for receiving latitude/longitude data of a current position by network communication with a base station, control means for recognizing the latitude/longitude data of the current position on the basis of the radio signals received by said reception means and the latitude/longitude data received by said communication means, and display means for displaying a map centered on the latitude/longitude data recognized by said control means,

wherein said reception means measures reception sensitivity with respect to the radio signals transmitted from the plurality of artificial satellites, and

said control means automatically changes a scale of the map displayed by said display means on the basis of the measurement result on the reception sensitivity in said reception means with respect to the radio signals.

4. A terminal according to claim 3, wherein

said reception means measures reception sensitivity with respect to radio signals transmitted from the plurality of artificial satellites upon reception of a request to scale down the map displayed by said display means, and

said control means automatically changes the scale of the map displayed by said display means on the basis of the measurement result on the reception sensitivity in said reception means with respect to the radio signals.

6. A terminal according to claim 3 or 4, wherein said control means accesses the Internet through said communication means and the base station, downloads a map whose scale is changed from a map server on the Internet on the basis of the measurement result on the reception sensitivity in said reception means with respect to the radio signals, and displays the map on said display means.

18. A map display method using the GPS terminal defined in claim 6, comprising the steps of:

causing the reception means to measure reception sensitivity with respect to radio signals transmitted from the plurality of artificial satellites upon reception of a request to scale down the map displayed by the display means; and

causing the control means to access the Internet through the communication means and the base station, download a map whose scale is changed from a map server on the Internet on the basis of the measurement result on the reception sensitivity in the reception means with respect to the radio signals, and display the map on the display means.

8. A position measuring system comprising a base station which is equipped with a GPS capable of network communication and receives radio signals transmitted from a plurality of artificial satellites, and a GPS terminal which is equipped with a GPS capable of network communication, receives radio signals transmitted from the plurality of artificial satellites, recognizes latitude/longitude data of a current position by performing network communication with said base station, and displays a map centered on the latitude/longitude data,

wherein said GPS terminal measures reception sensitivity with respect to the radio signals transmitted from the plurality of artificial satellites, and automatically changes a scale of the displayed map on the basis of the measurement result.

9. A system according to claim 8, wherein

said GPS terminal comprises:

reception means for receiving radio signals transmitted from a plurality of artificial satellites and measuring reception sensitivity with respect to the radio signals transmitted from the plurality of artificial satellites;

communication means for receiving latitude/longitude data of a current position of said GPS terminal by performing network communication with said base station;

control means for recognizing the latitude/longitude data of the current position on the basis of the radio signals received by said reception means and the latitude/longitude data received by said communication means; and

display means for displaying a map centered on the latitude/longitude data recognized by said control means, and

said control means automatically changes a scale of the map displayed by said display means on the basis of the measurement result in said reception means with respect to the radio signals.

10. A terminal according to claim 9, wherein

said reception means measures reception sensitivity with respect to radio signals transmitted from the plurality of artificial satellites upon reception of a request to scale down the map displayed by said display means, and

said control means automatically changes the scale of the map displayed by said display means on the basis of the measurement result on the reception sensitivity in said reception means with respect to the radio signals.

12. A system according to claim 10, wherein

said GPS terminal comprises:

reception means for receiving radio signals transmitted from a plurality of artificial satellites;

communication means for receiving latitude/longitude data of a current position of said GPS terminal by performing network communication with said base station;

control means for recognizing the latitude/longitude data of the current position on the basis of the radio signals received by said reception means and the latitude/longitude data received by said communication means;

display means for displaying a map centered on the latitude/longitude data recognized by said control means,

said communication means receives the measurement result on the reception sensitivity in said reception means with respect to the radio signals, which is transmitted from said base station, and

said control means automatically changes the scale of the map displayed by said display means on the basis of the measurement result on the reception sensitivity in said reception means with respect to the radio signals, which is received by said communication means.

13. A system according to claim 12, wherein

said communication means receives the measurement result on the reception sensitivity in said reception means with respect to the radio signals from the plurality of artificial satellites, which is transmitted from said base station, upon reception of a request to scale down the map displayed by said display means, and

said control means automatically changes the scale of the map displayed by said display means on the basis of the measurement result on the reception sensitivity in said reception means with respect to the radio signals, which is received by said communication means.

14. A system according to any one of claims 9, 10, 12, and 13, wherein

said GPS terminal comprises storage means for storing a wide-area map in advance, and

said control means displays the wide-area map stored in said storage means upon changing a scale of the wide-area map on the basis of the measurement result on the reception sensitivity in said reception means with respect to the radio signals transmitted f from the plurality of artificial satellites.

15. A map display method using the position measuring system defined in claim 14, comprising the step of causing the control means to display the wide-area map stored in the storage means upon changing the scale of the map on the basis of the measurement result on the reception sensitivity in the reception means with respect to the radio signals transmitted from the plurality of artificial satellites.

16. A system according to any one of claims 9, 10, 12, and 13, wherein said control means accesses the Internet through said communication means and the base station, downloads a map whose scale is changed from a map server on the Internet on the basis of the measurement result on the reception sensitivity in said reception means with respect to the radio signals transmitted from the plurality of artificial satellites, and displays the map on said display means.

17. A map display method using the position measuring system defined in claim 16, comprising the step of causing the control means to access the Internet through the communication means and the base station, download a map whose scale is changed from a map server on the Internet on the basis of the measurement result on the reception sensitivity in the reception means with respect to the radio signals transmitted from the plurality of artificial satellites, and display the map on the display means.

11. A position measuring system comprising a base station which is equipped with a GPS capable of network communication and receives radio signals transmitted from a plurality of artificial satellites, and a GPS terminal which is equipped with a GPS capable of network communication, receives radio signals transmitted from the plurality of artificial satellites, recognizes latitude/longitude data of a current position by performing network communication with said base station, and displays a map centered on the latitude/longitude data,

wherein said base station measures reception sensitivity in said GPS terminal with respect to the radio signals transmitted from the plurality of artificial satellites, and transmits the measurement result to said GPS terminal, and

said GPS terminal automatically changes a scale of the displayed map on the basis of the measurement result on the reception sensitivity in said GPS terminal with respect to the radio signals, which is transmitted from said base station.