Motion-based adaptive frequency estimation of a doppler velocity sensor

• US 8,917,203 B2
• Filed: 06/21/2011
• Issued: 12/23/2014
• Est. Priority Date: 06/21/2011
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Ingvalson, Ryan, McCroskey, Robert C., Hawkinson, Wesley J.
• Primary Examiner(s): McGue, Frank J
• Application Number:
  US13/164,889
• Publication Number:
  US 20120326918A1
• Time in Patent Office: 1,281 Days
• Field of Search: 342/104
• US Class Current: 342/104
• CPC Class Codes: G01C 21/10 by using measurements of speed or acceleration G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01S 13/60 wherein the transmitter and receiver are mounted on the moving object, e.g. for determining ground speed, drift angle, ground track G01S13/64 takes precedence
• CPC Class Codes: G01S 13/86 Combinations of radar systems with non-radar systems, e.g. sonar, direction finder

Abstract

A system and method for motion-based adaptive frequency estimation of a Doppler sensor is provided. The system comprises a Doppler sensor configured to output a digitized Doppler data signal, and a Doppler velocity estimation module operatively coupled to the Doppler sensor to receive the Doppler data signal. An inertial navigation system is operatively coupled to the Doppler velocity estimation module, and one or more inertial sensors is operatively coupled to the inertial navigation system. The inertial sensors are configured to transmit inertial navigation data to the inertial navigation system. The Doppler velocity estimation module calculates a speed or velocity estimate based on the Doppler data signal and the inertial navigation data. The speed or velocity estimate is then transmitted to the inertial navigation system.

Claims

1. A system for motion-based adaptive frequency estimation of a Doppler sensor, the system comprising:

a Doppler sensor configured to output a digitized Doppler data signal;

a Doppler velocity estimation module operatively coupled to the Doppler sensor to receive the Doppler data signal;

an inertial navigation system configured to receive data output from the Doppler velocity estimation module;

one or more inertial sensors operatively coupled to the inertial navigation system and configured to transmit inertial data to the inertial navigation system; and

a feedback loop directly between the inertial navigation system and the Doppler velocity estimation module;

wherein the Doppler velocity estimation module calculates a speed or velocity estimate based on the Doppler data signal and navigation data that is transmitted directly to the Doppler velocity estimation module from the inertial navigation system in the feedback loop;

wherein the speed or velocity estimate is transmitted directly to the inertial navigation system from the Doppler velocity estimation module as part of the feedback loop.

2. The system of claim 1, wherein the Doppler velocity estimation module further calculates an error estimate for the speed or velocity estimate, and the error estimate is transmitted to the inertial navigation system.

3. The system of claim 1, wherein the Doppler data signal includes in-phase or quadrature-phase data.

4. The system of claim 1, wherein the inertial sensors are implemented in an inertial measurement unit.

5. The system of claim 1, wherein the Doppler velocity estimation module comprises a frequency estimation algorithm configured to receive the Doppler data signal, and a parameter selection block configured to transmit frequency estimation parameters to the frequency estimation algorithm.

6. The system of claim 5, wherein the frequency estimation algorithm is configured to compute an estimated frequency based on the Doppler data signal and the frequency estimation parameters.

7. The system of claim 5, wherein the frequency estimation parameters include number of data points and length of zero-padding.

8. The system of claim 5, wherein the Doppler velocity estimation module further comprises a speed/velocity estimation block configured to calculate an average speed based on frequency data, or an average velocity based on frequency data and direction data.

9. The system of claim 5, wherein the Doppler velocity estimation module further comprises an error estimation block configured to calculate total error in average speed or average velocity.

10. The system of claim 5, wherein the Doppler velocity estimation module further comprises a data segment selection block operatively coupled to the parameter selection block.

11. A method for motion-based adaptive frequency estimation of a Doppler sensor, the method comprising:

receiving a digitized Doppler data signal from the Doppler sensor in a Doppler velocity estimation module;

transmitting inertial data from an inertial measurement unit to an inertial navigation system;

transmitting inertial navigation data directly to the Doppler velocity estimation module from the inertial navigation system in a feedback loop;

determining Doppler frequency estimation parameters based on the inertial navigation data;

calculating a Doppler frequency estimate based on the Doppler data signal and the frequency estimation parameters;

calculating an average speed or velocity estimate based on the Doppler frequency estimate; and

transmitting the average speed or velocity estimate directly to the inertial navigation system from the Doppler velocity estimation module as part of the feedback loop.

12. The method of claim 11, further comprising calculating an error estimate for the Doppler frequency estimate.

13. The method of claim 11, wherein the digitized Doppler data signal includes in-phase or quadrature-phase data.

14. The method of claim 11, wherein the digitized Doppler data includes in-phase and quadrature-phase data.

15. The method of claim 11, wherein the frequency estimation parameters include number of data points and length of zero-padding.

16. The method of claim 11, wherein the average speed is estimated by using a scaling factor to convert the estimated frequency to the average speed estimate.

17. The method of claim 11, wherein the average velocity is estimated by using a scaling factor to convert the estimated frequency to the average speed estimate, and determining a sign of the average speed estimate based on a direction indicator.

18. A computer program product, comprising:

a computer readable medium having instructions stored thereon executable by a processor to perform a method for motion-based adaptive frequency estimation of a Doppler sensor according to the method of claim 11.

19. A method for motion-based adaptive frequency estimation of a Doppler sensor, the method comprising:

(a) obtaining velocity and acceleration data from an inertial navigation system;

(b) determining whether the velocity and acceleration data is valid;

(c) when the velocity and acceleration data is valid, selecting a data time region and directing the velocity and acceleration data directly to the Doppler velocity estimation module from the inertial navigation system in a feedback loop;

(d) determining Doppler frequency estimation parameters based on the velocity and acceleration data;

(e) determining whether the frequency estimation parameters are valid;

(f) if the frequency estimation parameters are not valid, determining whether iterations are required;

(g) if the iterations are required, returning to (c) to select another data time region and repeating (d) and (e);

(h) if the frequency estimation parameters are valid, obtaining digitized Doppler data;

(i) determining whether the Doppler data is valid;

(j) if the Doppler data is valid, calculating a Doppler frequency estimate based on the Doppler data and the frequency estimation parameters;

(k) determining whether the Doppler frequency estimate is valid;

(l) if the Doppler frequency estimate is valid, calculating an average speed or velocity estimate based on the Doppler frequency estimate; and

(m) transmitting the average speed or velocity estimate directly to the inertial navigation system from the Doppler velocity estimation module as part of the feedback loop.

20. A computer program product, comprising:

a computer readable medium having instructions stored thereon executable by a processor to perform a method for motion-based adaptive frequency estimation of a Doppler sensor according to the method of claim 19.