Method and apparatus for performing timing synchronization

• US 6,829,534 B2
• Filed: 01/07/2003
• Issued: 12/07/2004
• Est. Priority Date: 04/23/1999
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Global Locate Incorporated (Broadcom, Inc.)
• Inventors: Abraham, Charles, Diggelen, Frank van, Fuchs, Donald L.
• Primary Examiner(s): Marc-Coleman, Marthe Y.
• Application Number:
  US10/338,134
• Publication Number:
  US 20030154025A1
• Time in Patent Office: 700 Days
• Field of Search: 701/213, 701/214, 701/200, 701/225, 701/226, 701/207, 342/358, 342/357.09, 342/357.01, 342/357.02, 342/357.06, 342/357.03, 455/574, 455/575
• US Class Current: 701/213
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/071 DGPS corrections
• CPC Class Codes: G01S 19/072 Ionosphere corrections
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• 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 19/258 relating to the satellite constellation, e.g. almanac, ephemeris data, lists of satellites in view
• CPC Class Codes: G01S 19/27 creating, predicting or correcting ephemeris or almanac data within the receiver
• 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 19/50 whereby the position solution is constrained to lie upon a particular curve or surface, e.g. for locomotives on railway tracks
• CPC Class Codes: G01S 2205/002 for traffic control, mobile tracking, guidance, surveillance or anti-collision
• CPC Class Codes: G01S 5/0036 of measured values, i.e. measurement on mobile and position calculation on base station
• CPC Class Codes: H04L 2027/0026 Correction of carrier offset
• CPC Class Codes: H04L 2027/0067 Phase error detectors
• CPC Class Codes: H04L 27/0014 Carrier regulation of chaotic carriers H04L27/001; for multicarrier receivers H04L27/2657

Abstract

A method and apparatus for performing timing synchronization in a mobile device. The method and apparatus include a wireless transceiver having a first oscillatory signal generator (OSG) and a Global Position System (GPS) receiver. The GPS receiver includes a second oscillatory signal generator coupled to a counter for receiving a first clock signal from the first OSG and a second clock signal from the second OSG. Additionally, a GPS signal processor is coupled to the counter. The counter provides a relative offset signal between the first and second oscillatory signal generators to the GPS signal processor for adjusting a pseudo-range model.

Claims

1. Apparatus for performing timing synchronization in a mobile device, comprising;

a wireless transceiver having a first oscillatory signal generator (OSG);

a Global Position System (GPS) receiver comprising;

a second oscillatory signal generator coupled to a counter for receiving a first clock signal from said first OSG and a second clock signal from said second OSG; and

a GPS signal processor coupled to said counter; and

wherein said counter provides a relative offset signal between said first and second oscillatory signal generators to said GPS signal processor to adjust a pseudo-range model.

2. The apparatus of claim 1, wherein:

said counter counts first clock cycles of said first clock signal that occur during a plurality of second clock cycles of said second clock signal; and

in response to a predetermined time interval elapsing, said counter provides said first clock signal to said GPS signal processor.

3. The apparatus of claim 1, wherein:

said counter counts first clock cycles of said first clock signal occurring during a plurality of second clock cycles of said second clock signal; and

in response to said plurality of second clock cycles equaling a predetermined value, said counter provides said first clock signal to said GPS signal processor.

4. The apparatus of claim 1, wherein:

said GPS signal processor determines an average frequency offset of said first OSG with respect to said second OSG.

5. The apparatus of claim 4, wherein said relative offset signal comprises a relative frequency offset determined from said average frequency offset.

6. The apparatus of claim 4, wherein said relative offset signal comprises a relative time offset determined from said average frequency offset.

7. The apparatus of claim 1, wherein said first oscillatory signal generator comprises a voltage controlled oscillator.

8. The apparatus of claim 1, wherein said second oscillatory signal generator comprises a temperature compensated crystal oscillator.

9. A method for performing timing synchronization in a mobile device, comprising:

synchronizing a first oscillatory signal generator (OSG) with a reference signal from a wireless carrier;

counting first clock cycles of said first OSG that occur during a plurality of second clock cycles from a second OSG;

terminating said count in response to attaining a predetermined metric;

computing a relative offset value between said first OSG and said second OSG; and

modifying a pseudo-range model based on said relative offset value.

10. The method of claim 9, wherein said predetermined metric comprises a predetermined time interval.

11. The method of claim 9, wherein said predetermined metric comprises a predetermined clock count of said second clock cycles.

12. The method of claim 9, wherein said relative offset value is a relative frequency offset value.

13. The method of claim 9, wherein said relative offset value is a relative time offset value.

14. The method of claim 9, wherein said computing step further comprises:

computing an average frequency offset of said first OSG with respect to said second OSG.

15. The method of claim 14, wherein said relative offset value comprises converting said average frequency offset to a relative time offset value.

16. The method of claim 14, wherein said relative offset value comprises converting said average frequency offset to a relative frequency offset value.