Positioning method using mobile terminal and mobile terminal having positioning function

1. A positioning method using a mobile terminal, said positioning method comprising:

acquiring, by said mobile terminal, position information on a neighboring mobile terminal from said neighboring mobile terminal;

gradually changing a field strength of a transmitted signal that is transmitted from said mobile terminal;

receiving, by said mobile terminal, a response signal from said neighboring mobile terminal in response to said transmitted signal;

estimating a distance between said mobile terminal and said neighboring mobile terminal, said estimation of said distance based on the field strength of the transmitted signal at a time that said response signal is received; and

calculating a position of said mobile terminal based on the estimated distance and said position information acquired from said neighboring mobile terminal.

2. The positioning method using the mobile terminal according to claim 1 , further comprising:

calculating a position of said neighboring mobile terminal based on position information on a mobile terminal existing near said neighboring mobile terminal; and

calculating the position of said mobile terminal based on the result of the calculation of the position of said neighboring mobile terminal.

3. The positioning method using the mobile terminal according to claim 2 , further comprising:

recursively repeating the acquisition of the position information in state of setting a limit to a number of times said neighboring mobile terminal acquires the position information from the mobile terminal existing near said neighboring mobile terminal so as not to acquire the position information repeatedly from one mobile terminal.

4. The positioning method of claim 1 , wherein said estimating step comprises:

estimating a distance between said mobile terminal and said neighboring mobile terminal, said estimation of said distance based on the field strength of the transmitted signal at a time that said response signal is received and not based on a signal propagation delay time between the mobile terminal and the neighboring mobile terminal.

5. A positioning method using a mobile terminal, said positioning method comprising:

acquiring, by said mobile terminal, position information on a neighboring mobile terminal from said neighboring mobile terminal;

gradually changing a reception sensitivity of said mobile terminal;

receiving, by said mobile terminal, a signal transmitted from said neighboring mobile terminal;

estimating a distance between said mobile terminal and said neighboring mobile terminal, said estimation of said distance based on the reception sensitivity of the mobile terminal at a time that said signal is received by said mobile terminal; and

calculating a position of said mobile terminal based on the estimated distance said position information acquired from said neighboring mobile terminal.

6. The positioning method using the mobile terminal according to claim 5 , further comprising:

calculating a position of said neighboring mobile terminal based on position information on a mobile terminal existing near said neighboring mobile terminal; and

calculating the position of said mobile terminal based on the result of the calculation of the position of said neighboring mobile terminal.

7. The positioning method using the mobile terminal according to claim 6 , further comprising:

recursively repeating the acquisition of the position information in state of setting a limit to a number of times said neighboring mobile terminal acquires the position information from the mobile terminal existing near said neighboring mobile terminal so as not to acquire the position information repeatedly from one mobile terminal.

8. The positioning method of claim 5 , wherein said estimating step comprises:

estimating a distance between said mobile terminal and said neighboring mobile terminal, said estimation of said distance based on the reception sensitivity of the mobile terminal at a time that said signal is received by said mobile terminal and not based on a signal propagation delay time between the mobile terminal and the neighboring mobile terminal.

9. A positioning method using a mobile terminal comprising the steps of:

acquiring position information on a neighboring mobile terminal existing near said mobile terminal from said neighboring mobile terminal existing nearby;

calculating the position of said mobile terminal based on said position information to perform positioning;

calculating the position of said neighboring mobile terminal based on position information on a mobile terminal existing near said neighboring mobile terminal; and

calculating the position of said mobile terminal based on the result of calculation; and

recursively repeating the acquisition of the position information in state of setting a limit to the number of times said neighboring mobile terminal acquires the position information from a mobile terminal existing near said neighboring mobile terminal so as not to acquire the position information repeatedly from one mobile terminal.

10. A positioning method using a mobile terminal comprising the steps of:

acquiring position information on a neighboring mobile terminal existing near said mobile terminal from said neighboring mobile terminal existing nearby;

calculating the position of said mobile terminal based on said position information to perform positioning;

measuring the distance between said mobile terminal and said neighboring mobile terminal; and

calculating the position of said mobile terminal based on the result of measurement and said position information acquired from said neighboring mobile terminal;

calculating the position of said neighboring mobile terminal based on position information on a mobile terminal existing near said neighboring mobile terminal; and

calculating the position of said mobile terminal based on the result of calculation; and

recursively repeating the acquisition of the position information in state of setting a limit to the number of times said neighboring mobile terminal acquires the position information from a mobile terminal existing near said neighboring mobile terminal so as not to acquire the position information repeatedly from one mobile terminal.

11. A mobile terminal having a positioning function, said mobile terminal comprising:

an antenna for transmitting and receiving signals;

neighboring mobile terminal communication unit for receiving, through said antenna, position information on a neighboring mobile terminal that is transmitted from said neighboring mobile terminal;

neighboring mobile terminal distance measuring unit for gradually changing a field strength of a transmitted signal that is transmitted from said antenna, and for receiving through said antenna a response signal from said neighboring mobile terminal in response to said transmitted signal, and for estimating a distance between said mobile terminal and said neighboring mobile terminal, said estimation of said distance based on the field strength of the transmitted signal at a time that said response signal is received; and

position information calculation unit for calculating a position of said mobile terminal based on the distance estimated by said neighboring mobile terminal distance measuring unit and based on the position information received by said neighboring mobile terminal communication unit.

12. The mobile terminal according to claim 11 , further comprising:

recursive cooperative positioning unit for adding a request for recursively repeating acquisition of position information on a mobile terminal existing near the neighboring mobile terminal to a signal transmitted from said neighboring mobile terminal communication unit to said mobile terminal existing near said neighboring mobile terminal.

13. The mobile terminal according to claim 12 , further comprising:

cooperative positioning duplication/divergence prevention unit for adding a request for limiting a number of times the position information is recursively acquired to a signal transmitted from said neighboring mobile terminal communication unit to the neighboring mobile terminal, and for preventing the acquisition of the position information repeatedly from one mobile terminal.

14. The mobile terminal of claim 11 ,

wherein said estimation of said distance by said neighboring mobile terminal distance measuring unit is not based on a signal propagation delay time between the mobile terminal and the neighboring mobile terminal.

15. A mobile terminal having a positioning function, said mobile terminal comprising:

an antenna for transmitting and receiving signals;

neighboring mobile terminal communication unit for receiving, through said antenna, position information on a neighboring mobile terminal that is transmitted from said neighboring mobile terminal;

neighboring mobile terminal distance measuring unit for gradually changing a reception sensitivity in said neighboring mobile terminal communcication unit, and for receiving a response signal form said neighboring mobile terminal communication unit when said neighboring mobile terminal communication unit receives signal, through said antenna, from said neighboring mobile terminal, and for estimation a distance between said mobile terminal and said neighboring mobile terminal, said estimation of said distance based on the reception sensitivity of the neighboring mobile terminal communication unit when said signal is received from said neighboring mobile terminal; and

position information calculation unit for calculating a position of said mobile terminal based on the distance estimated by said neighboring mobile terminal distance measuring unit and based on the position information received by said neighboring mobile terminal communication unit.

16. The mobile terminal according to claim 15 , further comprising:

recursive cooperative positioning unit for adding a request for recursively repeating acquisition of position information on a mobile terminal existing near the neighboring mobile terminal to a signal transmitted from said neighboring mobile terminal communication unit to said mobile terminal existing near said neighboring mobile terminal.

17. The mobile terminal according to claim 16 , further comprising:

cooperative positioning duplication/divergence prevention unit for adding a request for limiting a number of times the position information is recursively acquired to a signal transmitted from said neighboring mobile terminal communication unit to the neighboring mobile terminal, and for preventing the acquisition of the position information repeatedly from one mobile terminal.

18. The mobile terminal of claim 15 ,

wherein said estimation of said distance by said neighboring mobile terminal distance measuring unit is not based on a signal propagation delay time between the mobile terminal and the neighboring mobile terminal.

19. A mobile terminal having a positioning function, comprising:

an antenna for transmitting and receiving a radio signal;

neighboring mobile terminal communicating means for transmitting position information on said mobile terminal through said antenna, and for receiving position information on a neighboring mobile terminal existing near said mobile terminal, transmitted from said neighboring mobile terminal, through said antenna;

position information calculating means for calculating the position of said mobile terminal based on the position information received by said neighboring mobile terminal communicating means; and

recursive cooperative positioning means for adding a request for recursively repeating acquisition of position information on a mobile terminal existing near a neighboring mobile terminal existing near said mobile terminal to a signal transmitted from said neighboring mobile terminal communicating means to said mobile terminal existing near said mobile terminal.

20. The mobile terminal having a positioning function according to claim 19 , further comprising:

neighboring mobile terminal distance measuring means for measuring the distance between said mobile terminal and said neighboring mobile terminal, and

wherein said position information calculating means calculates the position of said mobile terminal based on the result of measurement in said neighboring mobile terminal distance measuring means, and the position information received by said neighboring terminal communicating means.

21. The mobile terminal having a positioning function according to claim 20 , further comprising:

cooperative positioning duplication/divergence preventing means for adding a request for limiting the number of times the position information is recursively acquired, and for preventing the acquisition of the position information repeatedly from one mobile terminal to a signal transmitted from said neighboring mobile terminal communicating means to a neighboring mobile terminal existing near said mobile terminal.

22. The mobile terminal having a positioning function according to claim 19 , further comprising:

cooperative positioning duplication/divergence preventing means for adding a request for limiting the number of times the position information is recursively acquired, and for preventing the acquisition of the position information repeatedly from one mobile terminal to a signal transmitted from said neighboring mobile terminal communicating means to a neighboring mobile terminal existing near said mobile terminal.