Method and system for acquiring pseudo-noise (PN) decade-code phase

• US 20030108085A1
• Filed: 12/06/2001
• Published: 06/12/2003
• Est. Priority Date: 12/06/2001
• Status: Active Grant

• Current Assignee: L3 Technologies, Inc. (L3Harris Technologies, Inc.)
• Original Assignee: Nokia Corporation
• Inventors: Keller, Merle L., Mower, Vaughn L., McEntire, Steve J.
• Granted Patent: US 7,054,350 B2
• Time in Patent Office: Days
• US Class Current: 375/145
• CPC Class Codes: H04B 1/70754 Setting of search window, i.e. range of code offsets to be searched H04B1/70758 takes precedence
• CPC Class Codes: H04B 1/70756 Jumping within the code, i.e. masking or slewing H04B1/70758 takes precedence

Abstract

A method and system for synchronizing the PN phase of a pseudo-noise (PN) coded signal with a phase of a master PN decade-code is provided. The method includes the steps of associating the master PN decade-code initialization t₀ with a first time zone reference date and time and determining an elapsed time t₁. The next steps equate the elapsed time t₁ to a corresponding phase of the master PN code and synchronize the phase of the PN coded signal with the corresponding phase of the master PN decade-code.

Claims

1. A method for synchronizing a phase of at least one pseudo-noise (PN) code with a phase of a master PN code, the master PN code having an initialization time t₀, the method comprising the steps of:

associating time t₀ with a first time zone reference date and time;

determining an elapsed time t₁;

substantially equating the elapsed time t₁ to a corresponding phase of the master PN code, wherein the PN code comprises a periodicity substantially greater than the elapsed time t₁; and

synchronizing the phase of the at least one PN code with the corresponding phase of the master PN code.

2. A method as in claim 1 wherein the step of determining the elapsed time t₁ further comprises the steps of:

determining a first local-time;

converting the first local-time to a first time zone current date and time; and

determining the time elapsed between the first time zone reference date and time and the first time zone current date and time.

3. A method as in claim 2 wherein the step of determining the first local-time further comprises the step of determining a first local Global Positioning System (GPS) time.

4. A method as in claim 3 wherein the step of determining the first local GPS time further comprises the step of receiving the first local GPS time from a plurality of satellites.

5. A method for synchronizing a phase of at least one pseudo-noise (PN) code with a phase of a master PN code, the master PN code having an initialization time t₀, the method comprising the steps of:

determining an elapsed time t₁;

substantially equating the elapsed time t₁ to a corresponding phase of the master PN code, wherein the PN code comprises a periodicity substantially greater than the elapsed time t₁; and

synchronizing the phase of the at least one PN code with the corresponding phase of the master PN code.

6. A method as in claim 5 wherein the step of determining the elapsed time t₁ further comprises the steps of:

providing a master clock;

initializing the master PN code and the master clock substantially simultaneously at the time t₀; and

determining from the master clock the time t₁.

7. A method as in claim 6 wherein the step of providing the master clock further comprises the step of providing a Global Positioning Satellite (GPS) clock signal.

8. A method as in claim 6 wherein the step of determining from the master clock the time t₁ further comprises the steps of:

providing at least one slave clock, wherein the initialization of the at least one slave clock is synchronized with the initialization of the master clock;

determining from the at least one slave clock the elapsed time t₁.

9. A system for acquiring a pseudo-noise (PN) coded signal, the PN coded signal having initialization time t₀, the system comprising:

a link control processor for capturing GPS time and converting the captured GPS time t₀ elapsed PN code chips since time t₀; and

a correlator for aligning the PN code phase in accordance with the elapsed PN code chips.

10. A system as in claim 9 wherein the system for acquiring a pseudo-noise (PN) coded signal further comprises:

a PN code generator, wherein the PN code generator comprises at least four PN component code generators G₁ . . . G₄ generating PN component codes PN₁ . . . PN₄, respectively.

11. A system as in claim 10 wherein each of the PN codes PN₁ . . . PN₄ comprise chip lengths substantially equal to a unique relatively prime number.

12. A method for GPS-aided, seamless acquisition of a pseudo noise (PN) coded signal, wherein the PN coded signal is modulated by a PN master code starting at a time t₀ in zone z₀, the method comprising the steps of:

determining a GPS time;

converting the GPS time t₀ a first estimate of elapsed number of chips associated with the PN master code; and

adjusting the first estimate of the elapsed number of chips associated with the PN master code to correlate with the PN coded signal.

13. A method as in claim 12 wherein the step of determining the GPS time further comprises the steps of:

determining a local GPS time; and

converting the local GPS time t₀ a second GPS time, wherein the second GPS time corresponds to the zone z₀.

14. A method as in claim 12 wherein the step of converting the GPS time t₀ the first estimate of elapsed number of chips associated with the PN master code further comprises the step of adding a predetermined number of chips to the first estimate.

15. A method as in claim 14 wherein the method for GPS-aided, seamless acquisition of a pseudo noise (PN) coded signal further comprises the step of synchronizing the first estimate of elapsed number of chips with the first PN coded signal.

16. A method as in claim 14 wherein the method for GPS-aided, seamless acquisition of a pseudo noise (PN) coded signal further comprises the step of slipping the first estimate of elapsed number of chips a predetermined amount of PN chips.

17. A method as in claim 16 wherein the step of slipping the first estimate of elapsed number of chips the predetermined amount further comprises the step of slipping the first estimate a predetermined maximum number of times.

18. A method as in claim 12 further comprising the step of:

providing the PN master code, wherein the step of providing the PN master code further comprises the step of;

combining at least four PN component codes PN₁ . . . PN₄, wherein the at least four PN component codes PN₁ . . . PN₄ comprise chip lengths substantially equal to a unique relatively prime number.

19. A method as in claim 18 wherein the step of providing the PN master code further comprises the step of:

determining the PN master code such that the PN master code operates continuously for a predetermined time span before repeating.

20. A method as in claim 19 wherein the step of determining the PN master code such that the PN master code operates continuously for the predetermined time span before repeating further comprises the step of determining the PN master code such that the PN master code operates continuously for at least ten years.