(12) United States Patent ao) Patent No.: us 6,195,041 Bi
Gardner et al. (45) Date of Patent: Feb. 27,2001
(54) RELIABLE POSITION LOCATION IN MEMORY LIMITED ENVIRONMENT
(75) Inventors: William Gardner, San Diego; Avneesh Agrawal, Sunnyvale; Gilbert C. Sih, San Diego; Qiuzhen Zou, San Diego; Inyup Kang, San Diego, all of CA (US)
(73) Assignee: Qualcomm Incorporated, San Diego, CA (US)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/150,409
(22) Filed: Sep. 9, 1998
(51) Int. CI.7 G01S 5/02; H04B 7/185
(52) U.S. CI 342/357.12; 342/357.1
(58) Field of Search 342/357.06, 357.12,
(56) References Cited
U.S. PATENT DOCUMENTS
5,420,592 5/1995 Johnson 342/357
5,495,499 2/1996 Fenton et al 375/205
5,663,734 9/1997 Krasner 342/357
FOREIGN PATENT DOCUMENTS
0488739 6/1992 (EP) G01S/5/14
Article Entitled "Global Positioning System Overview", by
Dana, published on website at www.host.cc.utexas.edu, Sep.
1994 revised Feb. 15, 1998 pp. 1-12.
Article entitled "Spread Spectrum Code Acquisition In the
Presence of Doppler Shift and Data Modulation", IEEE
Transactions on Comm., vol. 38 No. 2 Feb. 1990 pp.
Understanding GPS Principles and Applications,/ Kaplan, Elliott D.. Boston MA: Artech House, 1996 Chapters 4 and 5.
Primary Examiner—-Thomas H. Tarcza
Assistant Examiner—Fred H Mull
(74) Attorney, Agent, or Firm—Philip Wadsworth; Charles Brown; Tom Streeter
The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment comprises a method for performing position location in a wireless communication system using a set of signals transmitted from a set of satellites including the steps of receiving signal samples, rotating an acquisition code by a first rotation amount yielding a rotated acquisition code, despreading said signal samples using rotated acquisition code yielding despread data, accumulating said despread data over a first duration yielding partially accumulated data, rotating said partially accumulated data by a second rotation amount yielding rotated data and accumulating said rotated data.
12 Claims, 12 Drawing Sheets