Position location with low tolerance oscillator

• US 6,665,539 B2
• Filed: 02/01/2001
• Issued: 12/16/2003
• Est. Priority Date: 09/09/1998
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sih, Gilbert C., Zou, Qiuzhen
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): LE, LANA N
• Application Number:
  US09/775,895
• Publication Number:
  US 20010005680A1
• Time in Patent Office: 1,048 Days
• Field of Search: 455/76, 455/456, 455/457, 455/85, 455/86, 342/357.12, 342/357.1
• US Class Current: 455/456.3
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: G01S 19/246 involving long acquisition integration times, extended snapshots of signals or methods specifically directed towards weak signal acquisition
• CPC Class Codes: G01S 19/254 relating to Doppler shift of satellite signals
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: G01S 2205/008 using a mobile telephone network

Abstract

The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment of the invention comprises a method of performing position location in a wireless subscriber unit having a local oscillator, including the steps of receiving a position location request, acquiring a timing signal when a sufficient period of time has elapsed since the local oscillator has been corrected and correcting the local oscillator using a correction signal based on the timing signal, substantially freezing the correction signal, performing a position location procedure using the local oscillator with the correction signal applied, and ending said position location procedure.

Claims

1. A method of performing position location in a wireless subscriber unit having a local oscillator, comprising the steps of:

receiving a position location request;

acquiring a timing signal a period of time after the local oscillator had been corrected and correcting said local oscillator using a correction signal based on said timing signal, substantially freezing the correction signal;

performing a position location procedure using the local oscillator with the correction signal applied; and

ending the position location procedure,

wherein said timing signal is a signal from among a set of GSM downlink channels of a GSM wireless communication system.

2. The method of claim 1, wherein the set of GSM downlink channels includes an assigned traffic channel mid-amble.

3. The method of claim 2, wherein the set of GSM downlink channels further includes a GSM frequency correction control channel.

4. The method of claim 1, wherein the set of GSM downlink channels includes a GSM frequency correction control channel.