POSITION ENGINE (PE) FEEDBACK TO IMPROVE GNSS RECEIVER PERFORMANCE

• US 20100171659A1
• Filed: 02/25/2010
• Published: 07/08/2010
• Est. Priority Date: 10/02/2008
• Status: Abandoned Application

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Ramasubramanian, Karthik, Waters, Deric Wayne, Rao, Sandeep
• Application Number:
  US12/712,520
• Publication Number:
  US 20100171659A1
• Time in Patent Office: Days
• US Class Current: 342/357.620
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter

Abstract

Embodiments of the invention provide a method for making information in the position engine (PE) available to the measurement engine (ME). With the right information the ME can reduce its power consumption, and improve its performance. Other circuits, devices, systems, methods of operation and processes of manufacture are also disclosed.

Claims

1. A Global Navigation Satellite System (GNSS) receiver comprising:

a power control circuit operable to impress a power controlling duty cycle on the receiver;

a measurement engine operable to process an incoming signal to obtain a plurality of measurements; and

a position engine operable to use a set of the plurality of measurements to compute a position and provide feedback to the power control circuit for setting the duty cycle.

2. The (GNSS) receiver of claim 1, wherein plurality of measurements comprising at least one measurement selected from the group consisting of:

pseudorange,

pseudorange rate, and

uncertainties of measurements.

3. The (GNSS) receiver of claim 2, wherein the feed back to the power control circuit comprising parameter(s) selected from the group consisting of:

a position uncertainty,

a position uncertainty threshold,

a value indicating difficulty of a current scenario,

the number of satellite signals used to compute location,

a specific duty-cycle,

a specific blanking pattern for a given duty-cycle,

a plurality of specific requirements for the measurement engine circuit,

an user speed.

4. The (GNSS) receiver of claim 3, wherein the plurality of specific requirements for the measurement engine includes a certain number of satellite signals that must have a certain signal strength before entering into a low-power state.

5. The (GNSS) receiver of claim 3, wherein the plurality of specific requirements for the measurement engine includes a certain required signal strength for a plurality of specific satellites.

6. The (GNSS) receiver of claim 3, wherein the position engine and measurement engine have a prearranged set of blanking patterns.

7. The (GNSS) receiver of claim 2, wherein position engine computes information regarding the movement of the GNSS receiver.

8. The (GNSS) receiver of claim 2, wherein position engine is further operable to detect when an error of a measurement of at least one of the plurality of measurements is consistently high.

9. The (GNSS) receiver of claim 8, wherein position engine is further operable to signal to the measurement engine that it may have locked onto a false peak.

10. A method of power control comprising:

processing a plurality of inputs to obtain an estimate of a position of a receiver;

computing other parameters related to position and velocity of the receiver;

feeding back at least one of these parameters to a power control circuit.

11. The method of claim 10, further comprising:

detecting when an error of a measurement from a plurality of measurements is consistently high.

12. The method of claim 11, further comprising:

signaling to a measurement engine that it may have locked into a false peak.

13. The method of claim 11, wherein detecting further comprising:

filtering an estimated pseudorange error over time;

a level of the filtered pseudorange error is communicated to the measurement engine.

14. The method of claim 11, wherein detecting further comprising:

filtering an estimated pseudorange error over time;

if the filtered pseudorange error is greater than a threshold then a false peak can be declared and communicated to the measurement engine.

15. The method of claim 14, wherein declaring further comprising at least one measurement selected from the group consisting of:

a flag declaring the presence or absence of a false peak,

a value specifying the confidence level in the declaration,

a value containing the probability that the measurement engine is tracking a false peak,

an estimate of where a true peak is located to help the measurement engine circuit decide where to search,

an uncertainty regarding a true peak location.

16. The method of claim 10, wherein the parameter(s) provided in feed back to the power control circuit is (are) used for setting a power-save duty-cycle and is (are) selected from the group consisting of:

a position uncertainty,

a position uncertainty threshold,

a value indicating difficulty of a current scenario,

the number of satellite signals used to compute location,

a specific duty-cycle,

a specific blanking pattern for a given duty-cycle,

a plurality of specific requirements for the measurement engine,

an user speed.

17. The method of claim 16, wherein the plurality of specific requirements for the measurement engine includes a certain number of satellite signals that must have a certain signal strength before entering into a low-power state.

18. The method of claim 16, wherein the plurality of specific requirements for the measurement engine includes a certain required signal strength for a plurality of specific satellites.

19. The method of claim 16, wherein the position engine and measurement engine have a prearranged set of blanking patterns.

20. The method of claim 10, wherein the power control circuit is a dumb power control circuit and the parameter provided in feed back to the dumb power control circuit is a specific duty cycle, the method further comprising:

enforcing the specific duty cycle.

21. The method of claim 10, wherein the power control circuit is a smart power control circuit, the method further comprising:

engaging a power save mode.

22. The method of claim 16, wherein the position uncertainty may be computed by using a dilution of precision (DOP) estimated error.

23. The method of claim 22, wherein the error may be a function of an estimated pseudorange error.

24. The method of claim 22, wherein the error may be a function of an estimated pseudorange rate error.

25. The method of claim 22, wherein the position uncertainty may be computed by filtering the DOP estimated error over time with a filter having the same or similar bandwidth as the filter used by the PE to compute the position.

26. The method of claim 16, wherein the position uncertainty may be computed by using a position error from a Kalman filter in the PE.

27. A method of power control comprising:

processing a plurality of satellite vehicle (SV) signals;

periodically generating outputs;

reading inputs from a position engine; and

adapting the behavior of a measurement engine.

28. The method of claim 27, wherein the adapting comprises changing a power-save mode behavior.

29. The method of claim 27, wherein the adapting comprises re-acquiring at least one of a plurality of satellite vehicle (SV) signals.

30. A method for detecting false peaks, said method comprising:

filtering an estimated pseudorange error over time;

declaring a false peak if the filtered pseudorange error is greater than a threshold;

31. A method of 30, said method further comprising:

communicating the false peak declaration to a measurement engine.

32. A method of 30, said method further comprising:

communicating the false peak declaration to a measurement engine and communicating a level of the filtered pseudorange error to a measurement engine.

33. A method of 30, said method further comprising:

communicating a level of the filtered pseudorange error to a measurement engine and the measurement engine makes the determination when to check for the false peak.