AGPS system using NTP server and method for determining the location of a terminal using a NTP server

• US 7,236,126 B2
• Filed: 07/27/2005
• Issued: 06/26/2007
• Est. Priority Date: 12/13/2004
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Jeon, Ji-Youn, Pyo, Jong-Sun
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): Nguyen; Nga X.
• Application Number:
  US11/190,544
• Publication Number:
  US 20060125685A1
• Time in Patent Office: 699 Days
• Field of Search: 342/357.09, 342/357.01, 342/357.15
• US Class Current: 342/357.62
• CPC Class Codes: G01S 19/05 providing aiding data

Abstract

Disclosed is a method for determining the location of a terminal in an AGPS system in a wireless LAN using AGPS data provided from a PDE (position determination entity) and time information provided from a NTP (network time protocol) server.

Claims

1. An AGPS (Assisted Global Positioning System) system using a NTP (Network Time Protocol) server in a wireless LAN, which comprises:

a terminal for sending an AGPS data requesting message and a time information requesting message using a wireless LAN and for determining a current location based on AGPS data and time information received in response to the requesting messages;

an access point for analyzing messages for the position determination entity and the time information received from the terminal, delivering the message to a corresponding server according to results of the analysis and for delivering a message received from the server to the terminal;

a position determination entity for generating AGPS data in response to the AGPS data requesting message received from the access point and for providing the generated AGPS data to the access point; and

another separate NTP server for generating synchronized time information in response to the time information requesting message received from the access point and providing the generated time information to the access point.

2. The AGPS system as claimed in claim 1, wherein said access point delivers the AGPS data requesting message received from the terminal to the position determination entity and the time information requesting message received from the terminal to the NTP server.

3. The AGPS system as claimed in claim 1, wherein said AGPS data requesting message has a format consisting of a protocol ID field specifying the AGPS data requesting message as a request for AGPS data, a real data message field and a real data size field specifying a size of the real data message.

4. The AGPS system as claimed in claim 1, wherein said AGPS data provided from the position determination entity has a format consisting of a protocol ID field which specifies the AGPS data as a response to the AGPS data requesting message, a real data message field and a real data size field specifying a size of the real data message.

5. The AGPS system as claimed in claim 1, wherein said time information requesting message has a format consisting of a protocol ID field specifying the time information requesting message as a request for time information, a not-defined field and a real data size field specifying a size of the not-defined field.

6. The AGPS system as claimed in claim 1, wherein said time information has a format consisting of a protocol ID field which specifies the time information as synchronized time information from the NTP server, a TOW (Time of Week) field containing UTC (Coordinated Universal Time), a week number field containing 10 bits representing a GPS week number and a real data size field specifying a total size of the TOW field and the week number field.

7. The AGPS system as claimed in claim 6, wherein said TOW field specifies time in seconds from Sunday and the week number field contains a Z-count which is a 29-bit binary number representing a fundamental GPS time unit and of which the 10 most significant bits represent a GPS week number.

8. The AGPS system as claimed in claim 3, wherein said access point analyzes the protocol ID field of a received message and sends the received message to the corresponding server or the terminal according to the results of the analysis.

9. The AGPS system as claimed in claim 4, wherein said access point analyzes the protocol ID field of a received message and sends the received message to the corresponding server or the terminal according to the results of the analysis.

10. The AGPS system as claimed in claim 5, wherein said access point analyzes the protocol ID field of a received message and sends the received message to the corresponding server or the terminal according to the results of the analysis.

11. The AGPS system as claimed in claim 6, wherein said access point analyzes the protocol ID field of a received message and sends the received message to the corresponding server or the terminal according to the results of the analysis.

12. The AGPS system as claimed in claim 1, wherein said terminal includes:

a communication unit for implementing the wireless LAN;

an AGPS unit for detecting an initial GPS location based on the AGPS data and time information delivered from the communication unit and calculating the current location of the terminal using GPS signals; and

a processor for delivering the AGPS data and time information received from the access point to the AGPS unit and controlling operations necessary to calculate the initial location of the terminal using the GPS signals.

13. A method for determining the location of a mobile terminal in an AGPS (Assisted Global Positioning System) system using a NTP (Network Time Protocol) server in a wireless LAN, which comprises the steps of:

when a terminal generates an AGPS data requesting message and a time information requesting message to use location-based services, sending the generated requesting messages to an access point;

when the access point receives messages from the terminal, analyzing the received messages and delivering respective messages to a position determination entity and a NTP server according to results of the analysis;

delivering response messages received from the position determination entity and the NTP server to the terminal; and

determining a location of the terminal based on the response messages.

14. The method as claimed in claim 13, wherein said AGPS data requesting message has a format consisting of a protocol ID field specifying the AGPS data requesting message as a request for AGPS data, a real data message field and a real data size field specifying the size of the real data message.

15. The method as claimed in claim 13, wherein said time information requesting message has a format consisting of a protocol ID field specifying the time information requesting message as a request for time information, a not-defined field and a real data size field specifying the size of the not-defined field.

16. The method as claimed in claim 14, wherein said step of analyzing the received messages and delivering the respective messages comprises:

analyzing the protocol ID field of the message received from the terminal;

when the received message is recognized as a request for AGPS data as a result of the protocol ID analysis, delivering the message to the position determination entity; and

when the received message is recognized as a request for time information as a result of the protocol ID analysis, delivering the message to the NTP server.

17. The method as claimed in claim 15, wherein said step of analyzing the received messages and delivering the respective messages comprises:

analyzing the protocol ID field of the message received from the terminal;

when the received message is recognized as a request for AGPS data as a result of the protocol ID analysis, delivering the message to the position determination entity; and

when the received message is recognized as a request for time information as a result of the protocol ID analysis, delivering the message to the NTP server.

18. The method as claimed in claim 13, wherein said response messages are a message containing synchronized time information provided from the NTP server and a message containing APGS data provided from the position determination entity in response to the requesting messages received through the access point.