초록 ▼

A method for locating mobile terminals is provided. First, information of a home Public Land Mobile Network (PLMN) of a target mobile terminal, the location of which is to be determined, is checked in response to a location service request from a client. Then, information of a visited PLMN, where th

A method for locating mobile terminals is provided. First, information of a home Public Land Mobile Network (PLMN) of a target mobile terminal, the location of which is to be determined, is checked in response to a location service request from a client. Then, information of a visited PLMN, where the target mobile terminal is currently located, is checked based on the checked information of the home PLMN. The home PLMN calculates location assistance information of the visited PLMN using specific location information of the visited PLMN. The location assistance information is transferred to the target mobile terminal. This allows location information of a mobile terminal to be obtained irrespective of the area or communication network where the mobile terminal is located. It is thus possible to locate a mobile terminal in an area where no location assistance information is provided.

대표청구항 ▼

1. A home Public Land Mobile Network (PLMN) method for locating mobile terminals, comprising the steps of: a) receiving a request message of location service for a target terminal which is roaming;b) checking information of a visited PLMN visited by the target terminal, in response to the request me

1. A home Public Land Mobile Network (PLMN) method for locating mobile terminals, comprising the steps of: a) receiving a request message of location service for a target terminal which is roaming;b) checking information of a visited PLMN visited by the target terminal, in response to the request message of location service;c) determining if the visited PLMN provides location assistance information using the checked information of the visited PLMN;d) if the visited PLMN does not provide location assistance information, calculating by the home PLMN, using information corresponding to a cell ID of the target terminal in the visited PLMN, location assistance information for performing Network Assisted Global Positioning System (A-GPS) positioning of the target terminal; ande) transferring the location assistance information to the target terminal. 2. The method according to claim 1, further comprising the step of: f) calculating, by the home PLMN, the location of the target terminal using a GPS pseudorange of the target terminal, wherein the GPS pseudorange is measured in the target terminal using the location assistance information. 3. The method according to claim 1, further comprising the step of: g) receiving, by the home PLMN, calculated location information from the target terminal, wherein the calculated location information is calculated using a GPS pseudorange measured by the target terminal and the GPS pseudorange is measured in the target terminal using the location assistance information. 4. The method according to claim 1, wherein step b) includes the step of receiving and checking an IP address of a Gateway GPRS Support Node (GGSN) of the visited PLMN of the target terminal from a server for storing registrant and roaming information of mobile terminals. 5. The method according to claim 1, wherein step d) includes the step of calculating GPS satellite orbit and geographical information of the visited PLMN visited by the target terminal, and then calculating valid location assistance information using the calculation result. 6. The method according to claim 1, wherein at step d), the home PLMN, including a database (DB) for allowing the home PLMN to obtain geographical information of each of a plurality of PLMNs using a cell ID of each of the PLMNs, detects geographical information of the visited PLMN from the database using the cell ID of the target terminal in the visited PLMN, and calculates location assistance information of the visited PLMN using the detected geographical information. 7. The method according to claim 1, wherein said step e) includes the step of transferring only location assistance information for acquiring an initial GPS signal, depending on available network resources or traffic states. 8. The method according to claim 1, wherein step e) includes the step of encapsulating and transmitting the location assistance information, IP information of the home PLMN and the target terminal, and a location information request instruction. 9. A home Public Land Mobile Network (PLMN) method for locating mobile terminals, comprising the steps of: a) receiving a request message of location service for a target terminal from a visited PLMN which the target terminal is roaming in, the request message including at least one a Cell ID;b) checking information of the visited PLMN visited by the target terminal, which is roaming, in response to the request message of location service;c) determining if the visited PLMN visited by the target terminal provides location assistance information;d) if the visited PLMN doesn't provide location assistance information, receiving information corresponding to the cell ID of the target terminal from the visited PLMN at the home PLMN, and calculating by the home PLMN, using the information corresponding to the cell ID of the target terminal, the location assistance information for performing Network Assisted Global Positioning System (A-GPS) positioning of the target terminal; ande) transferring the location assistance information to the target terminal. 10. The method according to claim 9, further comprising the steps of: f) receiving, by the visited PLMN, calculated location information from a home PLMN, wherein the calculated location information is calculated in the home PLMN using a GPS pseudorange measured by the target terminal and the GPS pseudorange is measured in the target terminal using the location assistance information; andg) transferring the calculated location information to a client terminal or the target terminal. 11. The method according to claim 9, further comprising the steps of g) receiving, by the visited PLMN, calculated location information from the target terminal, wherein the calculated location information is calculated in the target terminal; andh) transferring the calculated location information to a client terminal. 12. The method according to claim 9, wherein at step b), a Serving GPRS (General Packet Radio Service) Support Node (SGSN) of the visited PLMN receives and checks an IP address of a Gateway Mobile Location Center (GMLC) of a home PLMN from a Visitor Location Register (VLR). 13. The method according to claim 9, wherein step d) includes the step of calculating GPS satellite orbit and geographical information of the visited PLMN visited by the target terminal, and then calculating valid location assistance information using the calculation result. 14. The method according to claim 9, wherein at step d), a home PLMN, including a database (DB) for allowing the home PLMN to obtain geographical information of each of a plurality of PLMNs using a cell ID of each of the PLMNs, detects geographical information of the visited PLMN from the database using the cell ID of the visited PLMN, and calculates location assistance information of the visited PLMN using the detected geographical information. 15. The method according to claim 9, wherein said step e) includes the step of transferring location assistance information for acquiring an initial GPS signal, depending on available network resources or traffic states. 16. The method according to claim 9, wherein step e) includes the step of encapsulating and transmitting the location assistance information, IP information of a home PLMN and the target terminal, and a location information request instruction. 17. The method according to claim 1, wherein the location assistance information is transmitted to the target terminal through the visited PLMN. 18. The method according to claim 1, wherein the information corresponding to the cell ID of the target terminal in the visited PLMN, the information is at least one of a GPS satellite orbit and a geographical information of a corresponding cell where the target terminal is located. 19. The method according to claim 1, wherein in the step of receiving a request message of location service for a target terminal which is roaming, the home PLMN receives the request message from the target terminal. 20. The method according to claim 19, wherein the request message includes at least a Cell ID of the target terminal. 21. The method according to claim 1, further comprising the steps of: receiving routing information of the target terminal; andrequesting information of the visited PLMN from the visited PLMN, the information including an IP address of a Gateway GPRS Support Node (GGSN) of the visited PLMN of the target terminal. 22. The method according to claim 1, further comprising the steps of: receiving, by the home PLMN, the information corresponding to a cell ID of the target terminal from the visited PLMN. 23. The method according to claim 9, wherein the information corresponding to the cell ID of the target terminal in the visited PLMN, includes at least one of a GPS satellite orbit and a geographical information of a corresponding cell where the target terminal is located. 24. The method according to claim 9, further comprising the steps of: receiving routing information of the target terminal; andrequesting information of the visited PLMN from the visited PLMN, the information including an IP address of a Gateway GPRS Support Node (GGSN) of the visited PLMN of the target terminal.