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US006208291B1
(12) United States Patent ao) Patent No.: us 6,208,291 Bi
Krasner (45) Date of Patent: Mar. 27,2001
(54) HIGHLY PARALLEL GPS CORRELATOR SYSTEM AND METHOD
(75) Inventor: Norman F. Krasner, San Carlos, CA (US)
(73) Assignee: SnapTrack, Inc., San Jose, 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.: 09/087,438
(22) Filed: May 29, 1998
(51) Int. C I. H04B 7/185
(52) U.S. CI 342/357.12; 342/357.06;
701/213; 375/208
(58) Field of Search 342/352, 357;
701/213; 375/208
(56) References Cited
U.S. PATENT DOCUMENTS
4,426,712 * 1/1984 Gorski-Popiel 375/96
4,660,164 4/1987 Leibowitz 364/728
4,841,544 * 6/1989 Nuytkens 375/1
5,576,715 * 11/1996 Litton et al 342/357
5,600,328 2/1997 Tachita et al 342/357
5,736,961 * 4/1998 Fenton et al 342/357
5,809,064 * 9/1998 Fenton et al 375/208
5,822,363 * 10/1998 Le Roy 375/206
FOREIGN PATENT DOCUMENTS
0 488 739 Al 6/1992 (EP) G01S/5/14
0 526 040 A2 2/1993 (EP) G01S/5/14
2 016 760 2/1978 (GB) G06F/15/34
WO 97/40398 10/1997 (WO) G01S/1/04
OTHER PUBLICATIONS
PCT Search Report mailed Sep. 30, 1998, 7 pages. Spilker, Jr., J.J.; Signal Structure and Theoretical Performance; Chapter 3: GSP Signal Structure and Theoretical Performance; pp. 57-83; American Institute of Aeronautics and Astronautics, Inc.; 1994.
* cited by examiner
Primary Examiner—-Thomas H. Tarcza
Assistant Examiner—Dao L. Phan
(74) Attorney, Agent, or Firm—Blakely, Sokoloff, Taylor & Zafman
(57) ABSTRACT
A method and apparatus of acquiring and tracking satellite positioning system signals in a highly parallel correlator disclosed. A pseudo-random noise correlation operation is performed on an input satellite positioning system signal to provide a correlated output. The input satellite positioning system signal is input in parallel to a number of parallel correlators. Each parallel correlator contains a multicorrelator unit which processes and stores multiple phases of a correlated pseudo-random noise signal using common adder and multiplier circuitry.
27 Claims, 8 Drawing Sheets
