Synchronization using multiple offset GNSS receiver channels

• US 9,671,497 B2
• Filed: 05/09/2014
• Issued: 06/06/2017
• Est. Priority Date: 05/09/2014
• Status: Active Grant

• Current Assignee: Javad GNSS, Inc.
• Original Assignee: Javad GNSS, Inc.
• Inventors: Ashjaee, Javad, Yudanov, Sergey
• Primary Examiner(s): LIU, HARRY K
• Application Number:
  US14/274,317
• Publication Number:
  US 20150323676A1
• Time in Patent Office: 1,124 Days
• Field of Search: 34235761
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/24 Acquisition or tracking or demodulation of signals transmitted by the system synchronisation aspects of direct sequence spread spectrum modulation H04B1/7073
• CPC Class Codes: G01S 19/243 Demodulation of navigation message

Abstract

Systems and methods for synchronizing a global navigation satellite system (GNSS) receiver with a GNSS signal are provided. In one example, a GNSS receiver may include one or more sets of 20 GNSS channels that are each configured to integrate a received GNSS signal over a 20 millisecond accumulation window to output a navigation message bit. The accumulation windows of the 20 GNSS channels may be delayed relative to other windows of the 20 GNSS channels by 1 millisecond. The GNSS receiver may identify one of the 20 GNSS channels having the correct synchronization with the GNSS signal based on the navigation message bits output by the 20 GNSS channels. The identified GNSS channel having the correct synchronization with the GNSS signal may be used to determine a location of the GNSS receiver.

Claims

1. A global navigation satellite system (GNSS) receiver, the receiver comprising:

an antenna configured to receive a GNSS signal;

a first plurality of GNSS channels coupled to receive the GNSS signal, wherein each of the first plurality of GNSS channels is configured to integrate the GNSS signal over an accumulation window having a predetermined length of time to output a navigation message bit, and wherein the accumulation windows of the first plurality of GNSS channels are delayed relative to each other;

a second plurality of GNSS channels coupled to receive the GNSS signal, wherein each of the second plurality of GNSS channels is configured to integrate the GNSS signal over an accumulation window having the predetermined length of time to output a navigation message bit, and wherein the accumulation windows of the second plurality of GNSS channels are delayed relative to each other; and

a processor coupled to receive the navigation message bits from the first plurality of GNSS channels, wherein the processor is configured to identify one of the first plurality of GNSS channels that is synchronized with the GNSS signal based on the navigation message bits.

2. The GNSS receiver of claim 1, wherein the first plurality of GNSS channels comprises 20 GNSS channels.

3. The GNSS receiver of claim 2, wherein the predetermined length of time is 20 milliseconds.

4. The GNSS receiver of claim 3, wherein the accumulation windows of the first plurality of GNSS channels are delayed relative to each other by 1 millisecond.

5. The GNSS receiver of claim 1, wherein each GNSS channel of the first plurality of GNSS channels are configured to demodulate the GNSS signal to produce an in-phase (Iphase) signal, and wherein integrating the GNSS signal over the accumulation window comprises integrating the Iphase signal over the accumulation window.

6. The GNSS receiver of claim 1, wherein identifying one of the first plurality of GNSS channels that is synchronized with the GNSS signal based on the navigation message bits comprises:

determining a power of each of the navigation message bits from the first plurality of GNSS channels; and

identifying the one of the first plurality of GNSS channels that is synchronized with the GNSS signal by identifying the GNSS channel outputting the navigation message bit having the highest power.

7. The GNSS receiver of claim 1, wherein the second plurality of GNSS channels comprises 20 GNSS channels.

8. The GNSS receiver of claim 1, wherein the accumulation windows of the second plurality of GNSS channels are delayed relative to each other by 1 millisecond.

9. The GNSS receiver of claim 1, wherein the first plurality of GNSS channels are configured to process signals from a first satellite, and wherein the second plurality of GNSS channels are configured to process signals from a second satellite.

10. A method for synchronizing a global navigation satellite system (GNSS) receiver with a GNSS signal, the method comprising:

receiving, at an antenna, the GNSS signal;

integrating, by each of a first plurality of GNSS channels, the GNSS signal over an accumulation window having a predetermined length of time to output a navigation message bit, wherein the accumulation windows of the first plurality of GNSS channels are delayed relative to each other;

integrating, by each of a second plurality of GNSS channels, the GNSS signal over an accumulation window having the predetermined length of time to output a navigation message bit, wherein the accumulation windows of the second plurality of GNSS channels are delayed relative to each other; and

identifying one of the first plurality of GNSS channels that is synchronized with the GNSS signal based on the navigation message bits.

11. The method of claim 10, wherein the first plurality of GNSS channels comprises 20 GNSS channels.

12. The method of claim 11, wherein the predetermined length of time is 20 milliseconds.

13. The method of claim 12, wherein the accumulation windows of the first plurality of GNSS channels are delayed relative to each other by 1 millisecond.

14. The method of claim 10, further comprising demodulating, by each of the first plurality of GNSS channels, the GNSS signal to produce an in-phase (Iphase) signal, wherein integrating, by each of the first plurality of GNSS channels, the GNSS signal over the accumulation window comprises integrating, by each of the first plurality of GNSS channels, the Iphase signal over the accumulation window.

15. The method of claim 10, wherein identifying one of the first plurality of GNSS channels that is synchronized with the GNSS signal based on the navigation message bits comprises:

determining a power of each of the navigation message bits from the first plurality of GNSS channels; and

identifying the one of the first plurality of GNSS channels that is synchronized with the GNSS signal by identifying the GNSS channel outputting the navigation message bit having the highest power.

16. The method of claim 10, wherein the second plurality of GNSS channels comprises 20 GNSS channels.

17. The method of claim 10, wherein the accumulation windows of the second plurality of GNSS channels are delayed relative to each other by 1 millisecond.

18. The method of claim 10, wherein the first plurality of GNSS channels are configured to process signals from a first satellite, and wherein the second plurality of GNSS channels are configured to process signals from a second satellite.