Adding multi-system functionalities to legacy navigation satellite system receivers

• US 8,860,610 B2
• Filed: 12/06/2011
• Issued: 10/14/2014
• Est. Priority Date: 12/06/2011
• Status: Active Grant

• Current Assignee: Qualcomm technologies international, ltd. (Qualcomm, Inc.)
• Original Assignee: Cambridge Silicon Radio Limited (Qualcomm, Inc.)
• Inventors: Hang, Daming, Qiu, Zongde, Tang, Rui, Babitch, Daniel
• Primary Examiner(s): LIU, HARRY K
• Application Number:
  US13/312,936
• Publication Number:
  US 20130141277A1
• Time in Patent Office: 1,043 Days
• Field of Search: 342/357.73
• US Class Current: 342/357.73
• CPC Class Codes: G01S 19/33 Multimode operation in different systems which transmit time stamped messages, e.g. GPS/GLONASS
• CPC Class Codes: G01S 19/425 by combining or switching between signals derived from different satellite radio beacon positioning systems

Abstract

Methods and apparatuses are disclosed for enabling a satellite-based navigation signal receiver to support multiple types of global navigation satellite systems (GNSS). A legacy GNSS receiver can support a plurality of GNSS types by software upgrade and with a new/modified radio frequency (RF) chip. There is no need to completely redesign a navigation host chip to support the multiple GNSS types. This invention offers a cost-efficient multi-GNSS solution without sacrificing the navigation performance. A GNSS baseband controller controls synchronization of measurement time for digitized data along a first signal processing path for a legacy GNSS signal and a second signal processing path for a non-legacy GNSS signal.

Claims

1. A method for determining a position of a navigation receiver, the method comprising:

receiving a first navigation signal from a first global navigation satellite system (GNSS) at a radio frequency (RF) chip coupled to a navigation host chip included in the navigation receiver;

receiving a second navigation signal from a second GNSS at the RF chip, where the second GNSS is a different type of GNSS than the first GNSS;

synchronizing measurement time for digitized data from the second navigation signal with the measurement time for digitized data from the first navigation signal; and

using the synchronized measurement data obtained from both the first navigation signal and the second navigation signal to calculate position of the navigation receiver.

2. The method of claim 1, wherein the first GNSS is global positioning system (GPS).

3. The method of claim 2, wherein the second GNSS is one of GLONASS and Compass.

4. The method of claim 1, wherein the second navigation signal comprises a plurality of frequency channels.

5. The method of claim 4, wherein the step of synchronizing further comprises:

maintaining a write pointer for the first navigation signal;

maintaining a write pointer and a plurality of read pointers for each of the frequency channels of the second navigation signal;

sending a trigger signal to a baseband controller when new measurement data is obtained from the first navigation signal;

updating a value of the write pointer of the first navigation signal based on the trigger signal;

searching the write pointers of the second navigation signal to identify a write pointer value that substantially matches with the updated value of the write pointer of the first navigation signal; and

synchronizing measurement data obtained from the second navigation signal with measurement data obtained from the first navigation signal.

6. The method of claim 1, wherein a same clock source is used to process analog mixing and to control sampling time to digitize analog signals from the first navigation signal and the second navigation signal.

7. The method of claim 1, wherein data from the first navigation signal and the second navigation signal are packed in a combined data packet by a packetizer included in the RF chip.

8. The method of claim 7, wherein a time stamp is included in a header of the combined data packet to maintain continuous timing information to counter data loss in the packetized data interface.

9. The method of claim 7, wherein a packetized data interface sends the combined data packet to a data driver that routes data from the first navigation signal to a first signal processing path and routes the data from the second navigation signal to a second signal processing path.

10. The method of claim 9, wherein the second signal processing path includes a soft correlator.

11. The method of claim 1, wherein data from various frequency channels of the second navigation signal are packed in a data packet by a packetizer included in the RF chip, while data from the first navigation signal remain separate.

12. The method of claim 11, wherein a packetized data interface sends the data packet to a data driver that routes data from the second navigation signal to a second signal processing path and a separate data interface routes data from the first navigation signal to a first signal processing path.

13. The method of claim 12, wherein the second signal processing path includes a soft correlator.

23. The method of claim 1, wherein synchronizing includes identifying a first measurement time for digitized data from the first navigation signal and finding a second measurement time for digitized data from the second navigation signal that most closely matches the first measurement time, the method further comprising obtaining synchronized measurement data from the digitized data from both the first and second navigation signals based on the synchronization.

24. The method of claim 1, further comprising:

adding timestamps to the digitized data from the first and second navigation signals, the timestamps corresponding to the respective measurement times,

wherein synchronizing includes using the timestamps.

14. A navigation receiver, comprising:

a radio frequency (RF) chip receiving a first navigation signal from a first global navigation satellite system (GNSS), and, a second navigation signal from a second GNSS, where the second GNSS is a different type of GNSS than the first GNSS; and

a navigation host chip coupled to the RF chip, wherein the navigation host chip synchronizes measurement time for digitized data from the second navigation signal with the measurement time for digitized data from the first navigation signal; and

, uses the synchronized measurement data obtained from both the first navigation signal and the second navigation signal to calculate position of the navigation receiver.

15. The device of claim 14, wherein the navigation host chip comprises a first signal processing path for the first navigation signal;

and, a second signal processing path for the second navigation signal.

16. The device of claim 15, wherein a GNSS baseband controller is coupled to both the first signal processing path and the second signal processing path to control synchronization of measurement time for digitized data along the first signal processing path and the second signal processing path.

17. The device of claim 15, wherein the second navigation signal comprises a plurality of frequency channels, and the second signal processing path includes a first-in-first-out (FIFO) data path and a corresponding soft correlator instance for each frequency channel.

18. The device of claim 15, wherein the first navigation signal comprises a single frequency channel, and the first signal processing path includes a first-in-first-out (FIFO) data path and a hardware-based correlator.

19. The device of claim 15, wherein data from the first navigation signal and the second navigation signal are packed in a combined data packet by a packetizer included in the RF chip.

20. The device of claim 19, wherein a packetized data interface sends the combined data packet to a data driver that routes data from the first navigation signal to the first signal processing path and routes data from the second navigation signal to the second signal processing path.

21. The device of claim 15, wherein data from various frequency channels of the second navigation signal are packed in a data packet by a packetizer included in the RF chip, while data from the first navigation signal remain separate.

22. The device of claim 21, wherein a packetized data interface sends the data packet to a data driver that routes data from the second navigation signal to the second signal processing path and a separate data interface routes data from the first navigation signal to the first signal processing path.

25. The device of claim 14, wherein synchronizing includes identifying a first measurement time for digitized data from the first navigation signal and finding a second measurement time for digitized data from the second navigation signal that most closely matches the first measurement time, the navigation chip further obtains synchronized measurement data from the digitized data from both the first and second navigation signals based on the synchronization.

26. The device of claim 14, wherein the navigation chip further adds timestamps to the digitized data from the first and second navigation signals, the timestamps corresponding to the respective measurement times, and wherein synchronizing includes using the timestamps.