Location system

• US 20040127229A1
• Filed: 07/22/2003
• Published: 07/01/2004
• Est. Priority Date: 07/31/2002
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Ishii, Kenichi
• Granted Patent: US 7,783,297 B2
• Time in Patent Office: Days
• US Class Current: 455/456.1
• CPC Class Codes: H04W 12/02 Protecting privacy or anonymity, e.g. protecting personally identifiable information [PII]
• CPC Class Codes: H04W 12/104 Location integrity, e.g. secure geotagging
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 4/029 Location-based management or tracking services
• CPC Class Codes: H04W 4/20 Services signaling; Auxiliary data signalling, i.e. transmitting data via a non-traffic channel
• CPC Class Codes: H04W 8/16 selectively restricting mobility data tracking

Abstract

A location system comprises a communication terminal for transmitting a location request specifying a target mobile terminal and a type of location information, and a location network. In response to the location request, the location network produces current location information of the target mobile terminal if the type of location information of the received request specifies current location information and transmits the current location information to the communication terminal and stores the last known location information in a memory as last known location information of the target mobile terminal. If the type of location information specifies last known location information, stored last known location information of the target mobile terminal is copied from the memory and transmitted to the communication terminal if the location request is verified by a privacy check and if the stored information is reusable.

Claims

1. A location system for locating a plurality of mobile terminals, comprising:

a communication terminal for transmitting a location request specifying a target mobile terminal and a type of location information; and

a location network responsive to said location request from said communication terminal for producing current location information of the target mobile terminal if the type of location information of the received request specifies current location information and transmitting the current location information to said communication terminal and storing the last known location information in a memory as last known location information of the target mobile terminal, and copying stored last known location information of the target mobile terminal from the memory if said type of location information specifies last known location information and transmitting the copied information to said communication terminal.

2. The location system of claim 1, wherein said location network performs a reusability test on the stored last known location information and transmits said last known location information if the reusability test indicates a favorable result and transmits said current location information if the reusability test indicates an unfavorable result.

3. The location system of claim 2, wherein said location request contains a parameter of last known location information, and wherein said location network performs said reusability test by using said parameter.

4. The location system of claim 2, wherein said parameter represents one of age and accuracy of last known location information.

5. The location system of claim 1, wherein said location network maintains privacy profile of the target mobile terminal, uses the privacy profile to perform a privacy check on said location request and transmits said last known location information if the privacy check indicates a favorable result.

6. The location system of claim 5, wherein said location network transmits a notification message to the target mobile terminal according to said privacy profile before transmitting said last known location information to said communication terminal.

7. The location system of claim 1, wherein said location network transmits a verification message to the target mobile terminal according to said privacy profile and transmits said last known location information to the communication terminal when the location system receives a verification report from the target mobile terminal which indicates that the location request is verified by the target mobile terminal.

8. The location system of claim 1, wherein said communication terminal is a client terminal.

9. The location system of claim 1, wherein said communication terminal is a mobile terminal which represents one of said plurality of mobile terminals.

10. The location system of claim 9, wherein said location network is responsive to said location request from one of said mobile terminals for producing current location information of a target mobile terminal if the type of location information specifies current location information and transmitting the current location information to said one mobile terminal and storing the last known location information in a memory as last known location information of the target mobile terminal, and copying last known location information of the target mobile terminal from the memory if said type of location information specifies last known location information and transmitting the copied information to said one mobile terminal.

11. The location system of claim 1, wherein said location network comprises:

a plurality of gateways for receiving said location request from said communication terminal, each of said gateways storing last known location information of home mobile terminals, said location request further containing a parameter of last known location information;

a plurality of registers associated respectively with said gateways; and

a plurality of wireless networks connected to said gateways for establishing wireless links to said mobile terminals,

each of said gateways being responsive to a location request from said communication terminal specifying one of said home mobile terminals as a target mobile terminal, (a) transmitting a copy of the stored last known location information of the target mobile terminal to the communication terminal if the type of location information of the location request specifies last known location information and if said parameter of last known location information is met by the stored last known location information, and (b) acquiring a node identifier from the associated register if said parameter is not met by the stored last known location information, acquiring current location information of the target mobile terminal from one of said wireless networks specified by the acquired node identifier and transmitting the acquired current location information to the communication terminal.

12. The location system of claim 11, wherein each of said gateways maintains privacy profiles of the home mobile terminals, and wherein each of the gateways transmits said copy of stored last known location information if said location request meets the privacy profile of the target mobile terminal.

13. The location system of claim 11, wherein said location network further comprises a plurality of privacy profile registers associated respectively with said gateways for storing privacy profiles of home mobile terminals of the associated gateway,

each of said gateways transmitting a request to the associated privacy profile register in response to receipt of said location request for requesting the associated register to make a decision as to whether the location request meets the privacy profile of the target mobile terminal, receiving a report indicating said decision, and transmitting said copy of last known location information if said decision is favorable.

14. The location system of claim 1, wherein said location network comprises:

a plurality of gateways for receiving said location request from said communication terminal, said location request further containing a parameter of last known location information;

a plurality of registers associated respectively with said gateways;

a plurality of wireless networks connected to said gateways for establishing wireless links to said mobile terminals, each of said wireless networks storing last known location information of home mobile terminals,

each of said gateways being responsive to a location request from said communication terminal specifying one of said home mobile terminals as a target mobile terminal, (a) acquiring a node identifier from the associated register, acquiring last known location information of the target mobile terminal from one of said wireless networks specified by the acquired node identifier if the type of location information of the location request specifies last known location information and if said parameter of last known location information is met by the stored last known location information, and (b) acquiring current location information of the target mobile terminal from said specified wireless network if said parameter is not met by the stored location information and transmitting the acquired current location information to the communication terminal.

15. The location system of claim 1, wherein said location network comprises:

a gateway including receive means for receiving a location request from a communication terminal, said request specifying a target mobile terminal and a type of location information; and

a wireless network including;

a memory;

control means for receiving the location request from said gateway and producing current location information of the target mobile terminal if the type of location information of the received request specifies current location information and storing the acquired current location information in said memory as last known location information of the target mobile terminal, and reading the stored last known location information of the target mobile terminal from said memory if said type of location information specifies last known location information; and

transmit means for transmitting, to said gateway, a copy of the acquired current location information or a copy of the last known location information read from said memory, depending on said type of last known location information,

said gateway further including transmit means for repeating said copy of current location information or last known location information to said communication terminal.

16. The location system of claim 15, wherein said location request further contains a parameter of last known location information, and a privacy profile of said target mobile terminal is stored in said memory,

wherein said control means includes reusability check means for performing a reusability test by checking said parameter with the stored privacy profile when said type of location information specifies last known location information and reading the stored last known location information from said memory when said reusability test indicates a favorable result.

17. The location system of claim 15, wherein said privacy profile indicates whether or not notification is required for notifying that the target mobile terminal is being accessed, and wherein said control means further includes notification means for transmitting a notification message to said target mobile terminal prior to the transmission of said last known location information to said communication terminal if said privacy profile of said target mobile terminal requires notification.

18. The location system of claim 15, wherein said privacy profile indicates whether or not the location request is verified by the target mobile terminal, and wherein said control means further includes verification means for transmitting a verification message to said target mobile terminal and receiving a verification report from the target mobile terminal prior to the transmission of said last known location information to said gateway if said privacy profile of said target mobile terminal indicates that verification by the target mobile terminal is required, and transmitting said copy of last known location information to said gateway if said verification report indicates a favorable result.

19. A location system comprising:

a communication terminal (101) for transmitting a location request specifying a target mobile terminal, a type of location information, and a parameter of last known location information;

a gateway (102) for storing last known location information of home mobile terminals and privacy profiles of the mobile terminals; and

a plurality of wireless networks (103, 104) for establishing a wireless link to mobile terminals,

said gateway (102) being responsive to said location request for performing a reusability test by checking said parameter with the privacy profile of the target mobile terminal if said type specifies last known location information, acquiring a node identifier from an associated register and current location information of the target mobile terminal from one of said wireless networks specified by said node identifier if said reusability test indicates an unfavorable result, transmitting the current location information from the gateway to the communication terminal, and storing the current location information in a memory as last known location information of said target mobile terminal,

said gateway transmitting a copy of last known location information of the target mobile terminal to the communication terminal if said reusability test indicates a favorable result.

24. The location system of claim 19, further comprising a second gateway (112) which, when visited by said target mobile terminal, operates as a repeater node between said one wireless network (113, 114) and said first gateway (102) for repeating said current location information.

20. A location system comprising:

a communication terminal (101) for transmitting a location request specifying a target mobile terminal, a type of location information, and a parameter of last known location information;

a gateway (102);

a register (106); and

a plurality of wireless networks (103, 104) for establishing a wireless link to mobile terminals and storing privacy profiles and location information of said mobile terminals,

said gateway (102) being responsive to said location request for (a) acquiring a node identifier from said register (106) if said type specifies last known location information, (b) authorizing one of a plurality of wireless networks specified by the node identifier to perform a reusability test by checking said parameter with the privacy profile of the target mobile terminal, (c) acquiring from current location information of the target mobile terminal from said one wireless network, and storing the current location information in a memory, and (d) acquiring a copy of the last known location information of the target mobile terminal from said one wireless network if said reusability test indicates a favorable result or a copy of the current location information if said reusability test indicates an unfavorable result and transmitting the copy of the last known location information or current location information to said communication terminal.

21. The location system of claim 20, wherein one of said mobile terminals transmits a location request specifying a target mobile terminal, a type of location information and a parameter of last known location information,

one of said wireless networks being responsive to a location request from said one mobile terminal for (a) performing a reusability test by checking said parameter with the privacy profile of the target mobile terminal if said type specifies last known location information, (b) producing current location information of the target mobile terminal if said reusability test indicates an unfavorable result, (c) transmitting the current location information to the requesting mobile terminal, (d) storing the current location information in a memory as last known location information of said target mobile terminal, and (e) transmitting a copy of last known location information of the target mobile terminal to the requesting mobile terminal if said reusability test indicates a favorable result.

22. A location system comprising:

a communication terminal (111) for transmitting a location request specifying a target mobile terminal, a type of location information, and a parameter of last known location information;

a first gateway (112);

a second gateway (102) for storing last known location information of home mobile terminals and privacy profiles of the mobile terminals;

first and second registers (116, 106) respectively associated with said first and second gateways; and

a plurality of wireless networks (103, 104) for establishing a wireless link to mobile terminals,

said first gateway (112) being responsive to said location request from said communication terminal for acquiring a node identifier specifying said second gateway from said first register (116), and transmitting said location request to said second gateway (102);

said second gateway (102) being responsive to the location request from the first gateway for (a) performing a reusability test by checking said parameter with the privacy profile of the target mobile terminal if said type of location information specifies last known location information, (b) acquiring a node identifier from said second register (106) and current location information of the target mobile terminal from one of said plurality of wireless networks specified by the node identifier if said reusability test indicates an unfavorable result, (c) transmitting the current location information to the communication terminal via the first gateway, (d) storing the current location information in a memory as last known location information of said target mobile terminal, and (e) transmitting a copy of last known location information of the target mobile terminal to the communication terminal via the first gateway (112) if said reusability test indicates a favorable result.

23. The location system of claim 22, further comprising a third gateway (122) which, when visited by said target mobile terminal, operates as a repeater node between said one wireless network (123, 124) and said second gateway (102) for repeating said current location information.

25. The location system of claim 22, wherein said first gateway (112) operates as a repeater node between said second gateway (102) and said one wireless network (103, 104) for repeating said current location information.

26. A location system comprising:

a communication terminal (101) for transmitting a location request specifying a target mobile terminal, a type of location information, and a parameter of last known location information;

a gateway (102);

a privacy profile register (107) for storing privacy profiles and location information of mobile terminals;

a home location register (106); and

a wireless network (103, 104) for establishing a wireless link to said mobile terminals,

said gateway being responsive to said location request for (a) authorizing said privacy profile register to perform a reusability test by checking said parameter with the privacy profile of the target mobile terminal if said type specifies last known location information, (b) receiving a report of said reusability test from said privacy profile register, (c) acquiring a node identifier from said home location register and current location information of the target mobile terminal from one of a plurality of wireless networks specified by said node identifier if said report indicates that said reusability test indicates an unfavorable result, (d) transmitting the current location information from the gateway to the communication terminal, (e) storing the current location information in a memory of said privacy profile register as last known location information of said target mobile terminal, and (f) transmitting a copy of last known location information of the target mobile terminal to the communication terminal if said report indicates that said reusability test indicates a favorable result.

32. The location system of claim 26, further comprising a second gateway (112) which, when visited by said target mobile terminal, operates as a repeater node between said first gateway (102) and said one wireless network (113, 114) for repeating said current location information.

27. A location system comprising:

a communication terminal (101) for transmitting a location request specifying a target mobile terminal and a type of location information;

a gateway (102) for storing last known location information of home mobile terminals;

a home location register (106);

a privacy profile register (107) for storing privacy profiles of the mobile terminals; and

a plurality of wireless networks (103, 104) for establishing a wireless link to mobile terminals,

said gateway being responsive to said location request for (a) authorizing said privacy profile register to perform a privacy check with the privacy profile of the target mobile terminal if said type specifies last known location information, (b) receiving a report of the privacy check from said privacy profile register, (c) acquiring a node identifier from said home location register and current location information of the target mobile terminal from one of said wireless networks specified by said node identifier if said report indicates that said privacy check indicates an unfavorable result, (d) transmitting the current location information from the gateway to the communication terminal, (e) storing the current location information in a memory as last known location information of said target mobile terminal, and (f) transmitting a copy of last known location information of the target mobile terminal to the communication terminal if said report indicates that said privacy check indicates a favorable result.

33. The location system of claim 27, further comprising a second gateway (112) which, when visited by said target mobile terminal, operates as a repeater node between said first gateway (102) and said one wireless network (113, 114) for repeating said current location information.

28. A location system comprising:

a communication terminal (111) for transmitting a location request specifying a target mobile terminal, a type of location information, and a parameter of last known location information;

first and second gateways (112, 102);

first and second home location registers (116, 106) respectively associated with said first and second gateways;

a privacy profile register (107) associated with said second gateway (102) for storing last known location information of home mobile terminals and privacy profiles of the mobile terminals; and

a plurality of wireless networks (103, 104) for establishing a wireless link to mobile terminals,

said first gateway (112) being responsive to said location request from said communication terminal for acquiring a node identifier specifying said second gateway (102) from said first home location register (116), and transmitting said location request to said second gateway (102);

said second gateway (102) being responsive to the location request from the first gateway (112) for authorizing the privacy profile register (107) to perform a reusability test by checking said parameter with the privacy profile of the target mobile terminal if said type of location information specifies last known location information and produce a report indicating a result of the reusability test,

said second gateway (102) being responsive to said report for acquiring a node identifier from said second home location register (106) and current location information of the target mobile terminal from one of said plurality of wireless networks specified by the node identifier if said report indicates that the result of the reusability test is unfavorable, transmitting the current location information to the communication terminal via the first gateway (112), and storing the current location information in a memory as last known location information of said target mobile terminal, and transmitting a copy of last known location information of the target mobile terminal to the communication terminal via the first gateway (112) if said report indicates that the result of the reusability test is favorable.

30. The location system of claim 28, further comprising a third gateway (122) which, when visited by said target mobile terminal, operates as a repeater node between said second gateway (102) and said one wireless network (123, 124) for repeating said current location information.

34. The location system of claim 28, wherein said first gateway (112) operates as a repeater node between said second gateway (102) and said one wireless network (113, 114) for repeating said current location information.

35. The location system of claim 28, wherein said first gateway (112) operates as a repeater node between said second gateway (102) and said one wireless network (113, 114) for repeating said current location information.

29. A location system comprising:

a communication terminal (111) for transmitting a location request specifying a target mobile terminal, a type of location information, and a parameter of last known location information;

a first gateway (112);

a second gateway (102) for storing last known location information of home mobile terminals;

first and second home location registers (116, 106) respectively associated with said first and second gateways;

a privacy profile register (107) associated with said second gateway (102) for storing privacy profiles of the mobile terminals; and

a plurality of wireless networks (103, 104) for establishing a wireless link to mobile terminals,

said first gateway (112) being responsive to said location request from said communication terminal for acquiring a node identifier specifying said second gateway (102) from said first home location register (116), and transmitting said location request to said second gateway (102);

said second gateway (102) being responsive to the location request from the first gateway (112) for authorizing the privacy profile register (107) to perform a privacy check with the privacy profile of the target mobile terminal to produce a report of the privacy check,

said second gateway (102) being responsive to said report for performing a reusability test by checking said parameter with the privacy profile of the target mobile terminal if said type of location information specifies last known location information and if the result of said privacy check is favorable,

said second gateway (102) acquiring a node identifier from said second home location register (106) and current location information of the target mobile terminal from one of said plurality of wireless networks specified by the node identifier if said reusability test indicates an unfavorable result, transmitting the current location information to the communication terminal via the first gateway (112), and storing the current location information in a memory as last known location information of said target mobile terminal, and transmitting a copy of last known location information of the target mobile terminal to the communication terminal via the first gateway (112) if said reusability test indicates a favorable result.

31. The location system of claim 29, further comprising a third gateway (122) which, when visited by said target mobile terminal, operates as a repeater node between said second gateway (102) and said one wireless network (123, 124) for repeating said current location information.

36. A gateway for operating with a location network to which mobile terminals are wirelessly connected, comprising:

receive means for receiving a location request from a communication terminal, said request specifying a target mobile terminal and a type of location information;

a memory;

control means for acquiring current location information of the target mobile terminal from said location network if the type of location information of the received request specifies current location information and storing the acquired current location information in said memory as last known location information of the target mobile terminal, and reading the stored last known location information of the target mobile terminal from said memory if said type of location information specifies last known location information; and

transmit means for transmitting, to said communication terminal, a copy of the acquired current location information or a copy of the last known location information read from said memory, depending on said type of last known location information.

37. The gateway of claim 36, wherein said location request further contains a parameter of last known location information, and a privacy profile of said target mobile terminal is stored in said memory,

wherein said control means includes reusability check means for performing a reusability test by checking said parameter with the stored privacy profile when said type of location information specifies last known location information and reading the stored last known location information from said memory when said reusability test indicates a favorable result.

38. The gateway of claim 36, wherein said privacy profile indicates whether or not notification is required for notifying that the target mobile terminal is being accessed, and wherein said control means further includes notification means for transmitting a notification message to said target mobile terminal prior to the transmission of said last known location information to said communication terminal if said privacy profile of said target mobile terminal requires notification.

39. The gateway of claim 36, wherein said privacy profile indicates whether or not the location request is verified by the target mobile terminal, and wherein said control means further includes verification means for transmitting a verification message to said target mobile terminal and receiving a verification report from the target mobile terminal prior to the transmission of said last known location information to said communication terminal if said privacy profile of said target mobile terminal indicates that verification by the target mobile terminal is required, and transmitting said copy of last known location information to said communication terminal if said verification report indicates a favorable result.

40. A location method comprising the steps of:

a) transmitting a location request from a communication terminal, said request specifying a target mobile terminal and a type of location information;

b) receiving the location request at a location network;

c) producing current location information of the target mobile terminal and transmitting the current location information from the location network to said communication terminal if the type of location information of the received request specifies current location information;

d) storing the current location information in a memory as last known location information of the target mobile terminal; and

e) copying the stored last known location information of the target mobile terminal from said memory if said type of location information specifies last known location information and transmitting the copied information from the location network to said communication terminal.

41. The location method of claim 40, wherein step (e) comprises the steps of performing a reusability test on said stored last known location information and transmitting said last known location information if said reusability test indicates a favorable result.

42. The location method of claim 41, wherein step (e) further comprises the steps of:

if said reusability test indicates an unfavorable result, producing current location information of the target mobile terminal and transmitting the current location information from the location network to said communication terminal; and

storing the current location information in said memory as last known location information of the target mobile terminal.

43. The location method of claim 41, wherein said location request contains a requested age of last known location information, and wherein step (e) comprises the steps of performing said reusability test by using said requested age and transmitting said copy of the stored last known location information if the stored last known location information meets said requested age.

44. The location method of claim 41, wherein said location request contains a requested age of last known location information, and wherein step (e) comprises the steps of:

performing said reusability test by using said requested age;

producing current location information of the target mobile terminal and transmitting the current location information from the location network to said communication terminal if the type of location information of the received request specifies current location information if said reusability test indicates that the stored last known information fails to meet the requested age; and

storing the current location information in said memory as last known location information of the target mobile terminal.

45. The location method of claim 40, wherein said location network maintains privacy profile of the target mobile terminal, and wherein step (e) comprises the steps of transmitting a notification message to the target mobile terminal according to said privacy profile, before transmitting said last known location information to the communication terminal.

46. The location method of claim 40, wherein said location network maintains privacy profile of the target mobile terminal, and wherein step (e) comprises the steps of transmitting a verification message to the target mobile terminal according to said privacy profile and transmitting said last known location information if a verification report from the target mobile terminal indicates that the location request is verified by the target mobile terminal.

47. The location method of claim 40, wherein said location network produces and transmits current location information of said target mobile terminal to said communication terminal if the stored location information of the target mobile terminal is not available and said type of location information indicates that current location information can be used instead of last known location information.

48. The location method of claim 40, wherein said communication terminal is a client terminal.

49. The location method of claim 40, wherein said communication terminal is a mobile terminal which represents one of said plurality of mobile terminals.

50. The location method of claim 48, further comprising the steps of:

transmitting a location request from one of said mobile terminals, said request specifying a target mobile terminal and a type of location information;

receiving said location request at said location network;

producing current location information of a target mobile terminal and transmitting the current location information from said location network to said one mobile terminal if the type of location information specifies current location information;

storing the current location information in a memory as last known location information of the target mobile terminal; and

copying the last known location information of the target mobile terminal from said memory if said type of location information specifies last known location information and transmitting the copied information from said location network to said one mobile terminal.

51. The location method of claim 40, wherein step (b) comprises the steps of performing a privacy check of the location request and performing steps (c) to (e) if said privacy check indicates a favorable result.

52. A method of operating a gateway with a location network, comprising the steps of:

a) receiving a location request from a communication terminal, said request specifying a target mobile terminal and a type of location information;

b) acquiring current location information of the target mobile terminal from said location network and transmitting the current location information to said communication terminal if the type of location information of the received request specifies current location information;

c) storing the current location information in a memory as last known location information of the target mobile terminal; and

d) transmitting a copy of the stored last known location information of the target mobile terminal to said communication terminal if said type of location information specifies last known location information.

53. The method of claim 52, wherein step (d) comprises the steps of performing a reusability test on said stored last known location information and transmitting said last known location information if said reusability test indicates a favorable result.

54. The method of claim 53, wherein step (d) further comprises the steps of:

if said reusability test indicates an unfavorable result, producing current location information of the target mobile terminal and transmitting the current location information from the location network to said communication terminal; and

storing the current location information in said memory as last known location information of the target mobile terminal.

55. The method of claim 53, wherein said location request contains a parameter of last known location information, and wherein step (d) comprises the steps of performing said reusability test by using said parameter and transmitting said last known location information if the reusability test indicates a favorable result.

56. The method of claim 55, wherein said parameter represents one of age and accuracy of last known location information.

57. The method of claim 52, wherein said location network maintains privacy profile of the target mobile terminal, and wherein step (d) comprises the step of transmitting a notification message to the target mobile terminal according to said privacy profile before said last known location information is transmitted to the communication terminal.

58. The method of claim 52, wherein said location network maintains privacy profile of the target mobile terminal, and wherein step (d) comprises the steps of transmitting a verification message to the target mobile terminal according to said privacy profile and transmitting said last known location information if a verification report from the target mobile terminal indicates that the location request is verified by the target mobile terminal.

59. The method of claim 52, wherein step (a) comprises the steps of performing a privacy check of the location request and performing steps (b) to (d) if said privacy check indicates a favorable result.

60. A communication terminal comprising:

transmit means for transmitting a location request to a location system in which last known location information of mobile terminals are stored, said location request specifying a target mobile terminal and a type of last known location information; and

receive means for receiving from said location system a copy of current location information of the target mobile terminal if said type specifies current location information or a copy of last known location information of the target mobile terminal if said type specifies last known location information.

61. The communication terminal of claim 60, wherein said location request further specifies a parameter of last known location information.

62. The communication terminal of claim 61, wherein said parameter represents one of age and accuracy of stored last known location information.

63. The communication terminal of claim 60, further comprising:

a memory for storing the current location information received from said location system as last known location information of said target mobile terminal; and

control means performing a reusability test on the last location information stored in said memory in response to a request from a user, displaying the last known location information if the reusability test indicates a favorable result.

64. A computer readable storage medium storing a program of operating a gateway with a location network, said program comprising the steps of:

a) receiving a location request from a communication terminal, said request specifying a target mobile terminal and a type of location information;

b) acquiring current location information of the target mobile terminal from said location network and transmitting the current location information to said communication terminal if the type of location information of the received request specifies current location information;

c) storing the current location information in a memory as last known location information of the target mobile terminal; and

d) transmitting a copy of the stored last known location information of the target mobile terminal to said communication terminal if said type of location information specifies last known location information.

65. The computer readable storage medium of claim 64, wherein step (d) comprises the steps of performing a reusability test on said stored last known location information and transmitting said last known location information if said reusability test indicates a favorable result.

66. The computer readable storage medium of claim 64, wherein step (d) further comprises the steps of:

if said reusability test indicates an unfavorable result, producing current location information of the target mobile terminal and transmitting the current location information from the location network to said communication terminal; and

storing the current location information in said memory as last known location information of the target mobile terminal.

67. The computer readable storage medium of claim 64, wherein said location request contains a parameter of last known location information, and wherein step (d) comprises the steps of performing said reusability test by using said parameter and transmitting said last known location information if the reusability test indicates a favorable result.

68. The computer readable storage medium of claim 67, wherein said parameter represents one of age and accuracy of last known location information.

69. The computer readable storage medium of claim 64, wherein said location network maintains privacy profile of the target mobile terminal, and wherein step (d) comprises the step of transmitting a notification message to the target mobile terminal according to said privacy profile before said last known location information is transmitted to the communication terminal.

70. The computer readable storage medium of claim 64, wherein said location network maintains privacy profile of the target mobile terminal, and wherein step (d) comprises the steps of transmitting a verification message to the target mobile terminal according to said privacy profile and transmitting said last known location information if a verification report from the target mobile terminal indicates that the location request is verified by the target mobile terminal.

71. The computer readable storage medium of claim 64, wherein step (a) comprises the steps of performing a privacy check of the location request and performing steps (b) to (d) if said privacy check indicates a favorable result.