Position determination using almanac for virtual base stations

• US 7,495,608 B1
• Filed: 06/16/2006
• Issued: 02/24/2009
• Est. Priority Date: 06/16/2006
• Status: Expired due to Fees

• Current Assignee: Cellco Partnership, Inc. (Verizon Communications Inc.)
• Original Assignee: Cellco Partnership, Inc. (Verizon Communications Inc.)
• Inventors: Zhou, Jingyi, Chen, Ben-Ren
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Nguyen; Nga X
• Application Number:
  US11/453,870
• Time in Patent Office: 984 Days
• Field of Search: 34235701-35717, 342/456.3, 342/455
• US Class Current: 342/357.43
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data

Abstract

Mobile station position determination through a wireless communication network, such as a preliminary fix for use in satellite acquisition assistance, utilizes wireless network almanac data defined in a “virtual” manner, for example, with regard to “virtual base stations.” A virtual base station (VBS) is a logical construct, essentially modeled from a number of actual base stations in a generally known region that use some common identification (e.g. the same SID/NID combination). The VBS has a coverage/service area approximating the aggregate coverage area of the actual base stations. The service provider offering acquisition assistance or a location based service need not know the precise locations of the actual base stations. Instead, the service provider can compile a virtual base station almanac (VBSA) based on the identification information and virtual base station location information, for example, to support the service(s) when the provider'"'"'s customers roam onto another carrier'"'"'s network facilities.

Claims

1. A method of determining position of at least one mobile station operating in a wireless communication network, comprising:

receiving messages from the at least one mobile station, each message including at least one item of information identifying a portion of a mobile wireless communication network through which the at least one mobile station is receiving wireless communication service;

based on identifying information in a first received message, accessing a record in a base station almanac (BSA) database for a base station through which a mobile station is receiving wireless communication service from among a plurality of records in the BSA database, each of the records in the BSA database providing position related information regarding a respective base station;

using the position related information from the accessed BSA database record to obtain a mobile station position fix, responsive to the first message;

based on identifying information in a second received message, accessing a record in a virtual base station almanac (VBSA) database for a region in which the mobile station is receiving wireless communication service from among a plurality of records in the database, each of the records in the VBSA database providing estimated location information for a region corresponding to combined service areas of defined group of base stations that utilize the same respective identifying information, wherein base stations of the defined group do not have position information indicated in records in the BSA; and

using the estimated location information for the region in which the mobile station is receiving wireless communication service, from the accessed VBSA database record, as an estimate of position of a mobile station, responsive to the second message.

2. The method of claim 1, wherein the use of the estimated location information comprises:

processing satellite position data for a constellation of satellites to obtain acquisition assistance data for a subset of the satellites of the constellation from which transmissions are expected to be receivable in the region in which the mobile station is receiving wireless communication service; and

transmitting the obtained acquisition assistance data to the mobile station for use in acquisition of a position measurement from one or more satellites of the subset.

3. The method of claim 2, wherein the obtained acquisition assistance data comprises a selected subset of almanac or ephemeris data for satellites of the global positioning system (GPS) from which transmissions are expected to be receivable within the region in which the mobile station is receiving wireless communication service.

4. The method of claim 1, wherein the at least one item of information included in the second received message comprises a System Identification (SID) and a Network Identification (NID) used by a defined group of base stations providing wireless communications service in the region in which the mobile station is receiving wireless communication service.

5. The method of claim 4, wherein:

the records of the VBSA database identify each respective virtual base station by a unique combination of SID and NID used by base stations of a network operator providing wireless communications service in a region corresponding to the respective virtual base station; and

each of the records of the VBSA database contains information as to position of a point in the region corresponding to the respective virtual base station.

6. The method of claim 5, wherein:

the estimated location information comprises information as to position of the center of the region corresponding to the respective virtual base station identified by the received SID and NID; and

the use of the estimated location information comprises;

(a) processing satellite position data for a constellation of satellites to obtain acquisition assistance data for a subset of the satellites of the constellation from which transmissions are expected to be receivable in a region corresponding to the respective virtual base station identified by the received SID and NID; and

(b) transmitting the obtained acquisition assistance data to the mobile station for use in acquisition of a position measurement from one or more satellites of the subset.

7. A position determining entity programmed to implement the method of claim 1.

8. A product comprising:

programming for causing a server to implement the method of claim 1, and a machine readable storage medium bearing the programming.

13. The method of claim 1, wherein:

the records in the BSA database provide the position related information with respect to base stations operated by a network service provider, and the identifying information in the first received message identifies a base station for which there is a record in the BSA database when the mobile station is receiving wireless communication service from one of the service provider'"'"'s base stations; and

the records in the VBSA database provide the estimated location information for regions associated with defined groups of base stations not operated by the service provider, and the identifying information in the second received message indicates that the mobile station is not receiving wireless communication service from one of the service provider'"'"'s base stations.

9. A system for estimating of position of at least one mobile station operating in a wireless communication network, comprising:

(1) a base station almanac (BSA) database comprising a record for each of a plurality of actual base stations of the wireless communication network each record for a respective actual base station including position information for the respective actual base station;

(2) a virtual base station almanac (VBSA) database comprising a record for each of a plurality of virtual base stations (VBSs), wherein;

(a) each VBS record contains location data regarding position of a point within a coverage region of a respective one of the VBSs;

(b) each VBS record is accessible using at least one item of identifying information used in common by base stations of a defined group providing wireless communications service in the coverage region of the respective one of the VBSs; and

(c) base stations of the defined group do not have position information indicated in records in the BSA; and

(3) a Position Determination Entity (PDE) having access to the BSA and VBSA databases and configured for data communication with the at least one mobile station through a portion of the wireless communication network, wherein the PDE is configured to;

(i) receive messages from the at least one mobile station, each message including at least one item of information identifying a portion of the wireless communication network through which the at least one mobile station is receiving wireless communication service;

(ii) in response to a first message in which the identifying information identifies a base station having a record in the BSA database, access the record for the identified based station in the BSA database based on the received identifying information, to obtain location data associated with the identified base station;

(iii) use the obtained location data associated with the identified base station for a mobile station position determination responsive to the first message;

(iv) in response to a second message in which the identifying information does not correspond to a base station having a record in the BSA database, access a VBS record in the VBSA database based on the identifying information in the second message, to obtain location data regarding position of a point within a coverage region corresponding to the VBS identified by the identifying information in the second message; and

(iv) use the obtained location data regarding the point within the coverage region corresponding to the identified VBS as an estimate of the position of a mobile station responsive to the second message.

10. The system of claim 9, wherein:

the point within in the coverage region of the respective one of the VBSs is an approximate center of the coverage region of the respective one of the VBSs; and

location data regarding position contained in each VBS record comprises latitude (LAT) and longitude (LON) of the approximate center of the coverage region of the respective one of the VBSs.

11. The system of claim 10, wherein each VBS record further contains a system identification (SID) and a network identification (NID) used in common by the base stations of the group providing wireless communications service in the coverage region of the respective one of the VBSs, for use as the at least one item of identifying information.

12. The system of claim 9, wherein the PDE is configured to use of the estimate of the position of the mobile station to:

process satellite position data for a constellation of satellites to obtain acquisition assistance data for a subset of the satellites of the constellation from which transmissions are expected to be receivable in the VBS coverage region in which the mobile station is receiving wireless communication service; and

transmit the obtained acquisition assistance data to the mobile station for use in acquisition of a position measurement from one or more satellites of the subset responsive to the second message.

14. System of claim 9, wherein:

the records in the BSA database provide the position related information with respect to base stations operated by a network service provider; and

the records in the VBSA database provide the estimated location information for regions associated with defined groups of base stations not operated by the service provider.