Reliable position location in memory limited environment

• US 6,195,041 B1
• Filed: 09/09/1998
• Issued: 02/27/2001
• Est. Priority Date: 09/09/1998
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kang, Inyup, Sih, Gilbert C., Agrawal, Avneesh, Gardner, William, Zou, Qiuzhen
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Mull, Fred H
• Application Number:
  US09/150,409
• Time in Patent Office: 902 Days
• Field of Search: 342/357.06, 342/357.12, 342/357.1
• US Class Current: 342/357.69
• 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 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: G01S 5/0063 of measured values, i.e. measurement on base station and position calculation on mobile
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

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.

Claims

1. A method for performing position location in a wireless communication system using a set of signals transmitted from a set of satellites comprising the steps of:

(a) receiving signal samples;

(b) rotating an acquisition code by a first rotation amount yielding a rotated acquisition code;

(c) despreading said signal samples using rotated acquisition code yielding despread data;

(d) accumulating said despread data over a first duration yielding partially accumulated data;

(e) rotating said partially accumulated data by a second rotation amount yielding rotated data; and

(f) accumulating said rotated data over a se and duration.

3. The method as set forth in claim 1 wherein steps (b)-(f) are performed for each satellite.

4. The method as set forth in claim 1 wherein said first duration is less than 2 ms.

5. The method as set forth in claim 1 wherein said second duration is greater than 10 ms.

6. The method as set forth in claim 1 wherein said accumulations are performed coherently.

2. The method as set forth in 1 wherein said first rotation amount corresponds to a larger offset and said second rotation amount corresponds to a smaller offset.

7. Apparatus for performing position location in a wireless communication system using a set of signals transmitted from a set of satellites, the apparatus comprising:

(a) means for receiving signal samples;

(b) means for rotating an acquisition code by a first rotation amount yielding a rotated acquisition code;

(c) means for despreading said signal samples using rotated acquisition code yielding despread data;

(d) means for accumulating said despread data over a first duration yielding partially accumulated data;

(e) means for rotating said partially accumulated data by a second rotation amount yielding rotated data; and

(f) means for accumulating said rotated data over a second duration.

8. The apparatus as set forth in claim 7 wherein said first rotation amount corresponds to a larger offset and said second rotation amount corresponds to a smaller offset.

9. The apparatus as set forth in claim 7 wherein means (b)-(f) are structured for performing for each satellite.

10. The apparatus as set forth in claim 7 wherein said first duration is less than 2 ms.

11. The apparatus as set forth in claim 7 wherein said second duration is greater than 10 ms.

12. The apparatus as set forth in claim 7 wherein said accumulating means are structured to perform such accumulations coherently.