USE OF GPS TO DETECT REPETITIVE MOTION

• US 20120200455A1
• Filed: 02/08/2011
• Published: 08/09/2012
• Est. Priority Date: 02/08/2011
• Status: Active Grant

• Current Assignee: Qualcomm technologies international, ltd. (Qualcomm, Inc.)
• Original Assignee: Cambridge Silicon Radio Limited (Qualcomm, Inc.)
• Inventors: Papagerogiou, Andrew
• Granted Patent: US 9,041,600 B2
• Time in Patent Office: Days
• US Class Current: 342/357.25
• CPC Class Codes: G01C 22/006 Pedometers
• CPC Class Codes: G01S 19/19 Sporting applications
• CPC Class Codes: G01S 19/30 code related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/37 Hardware or software details of the signal processing chain
• CPC Class Codes: G01S 19/40 Correcting position, velocity or attitude
• CPC Class Codes: G01S 19/43 using carrier phase measurements, e.g. kinematic positioning; using long or short baseline interferometry

Abstract

A system mounted to an object for detecting repetitive motion of the object. The system includes a GPS receiver for receiving GPS signals while being maneuvered in a repetitive motion by the object, and a processor for detecting repetitive phase shifts in the received GPS signals. In general, the system computes the repetitive motion of the GPS receiver based on the repetitive phase shifts.

Claims

1. A system mounted to an object for detecting repetitive motion of the object, comprising:

a GPS receiver for receiving GPS signals while being maneuvered in a repetitive motion by the object;

a processor for detecting repetitive phase shifts in the received GPS signals, and computing the repetitive motion of the GPS receiver based on the repetitive phase shifts.

2. The system of claim 1, including

a correlator for correlating the received GPS signals with known reference signals to produce correlation values;

and

a buffer for buffering a predetermined number of correlation values,

wherein the predetermined number of correlation values are used by the processor to detect the repetitive phase shifts in the received GPS signals.

3. The system of claim 2, including

a GPS tracking filter for tracking the received GPS signals based on the correlation values and repetitive phase shifts,

wherein the repetitive phase shifts are used by the GPS tracking filter to predict phase jitter in the GPS signals.

4. The system of claim 2, wherein

the correlator correlates GPS signals received by a plurality of GPS satellites, and

the processor detects the repetitive phase shifts by combining respective repetitive phase shifts for the plurality of satellites.

5. The system of claim 1, including

a processor for computing a location of the system based on the repetitive motion;

a memory for storing the computed location and repetitive motion over a period of time; and

a display for displaying the location and repetitive motion information to a user.

6. The system of claim 2, wherein

the processor detects the repetitive phase shifts by monitoring successive correlation values stored in the buffer and detecting a repeating pattern.

7. A cellular phone configured to be attached to a user, comprising:

a GPS receiver for receiving GPS signals while being maneuvered in a repetitive motion by the user; and

a processor for detecting repetitive phase shifts in the GPS signals, computing repetitive motion of the cellular phone and location of the cellular phone based on the repetitive phase shifts, and passing the detected repetitive phase shifts to an application running on the cellular phone.

8. A system mounted to an object for computing a location of the object, comprising:

a GPS receiver for receiving GPS signals while being maneuvered in a repetitive motion by the object;

a processor for detecting repetitive phase shifts in the GPS signals, and computing a location of the GPS receiver by compensating for the repetitive phase shifts.

9. The system of claim 8, including

a correlator for correlating the received GPS signals with known reference signals to produce correlation values;

and

a GPS tracking filter for tracking the GPS signals based on the correlation values and the repetitive phase shifts computed by the processor.

10. The system of claim 9, wherein

the GPS tracking filter is an adaptive Kalman filter which tracks the GPS signals by predicting phase changes in the correlation values based on the repetitive phase shifts.

11. The system of claim 9, wherein

the GPS tracking filter tracks GPS signals for a plurality of satellites, and

the processor computes repetitive phase shifts for each of the plurality of satellites.

12. The system of claim 11, wherein

the repetitive phase shifts for each satellite are weighted and averaged based on the carrier to noise power ratio for each respective satellites, and the weighted average is utilized by the GPS tracking filter to predict phase changes in the correlation values, and

a clock of the system is adjusted based on the predicted phase changes.

13. The system of claim 8, including

a memory for storing the location and repetitive motion information computed based on the phase shifts, and

a port for connecting the system to a personal computer,

wherein the system uploads the stored information to the personal computer through the port.

14. The system of claim 9, wherein

the processor compares the repetitive phase shifts to a satellite reference phase computed by the GPS tracking filter.

15. A method of detecting repetitive motion of an object, where a GPS receiver is mounted to the object being maneuvered in a repetitive motion, the method comprising:

receiving, by the GPS receiver, GPS signals;

detecting, by a processor, repetitive phase shifts in the received GPS signals, and computing the repetitive motion of the GPS receiver based on the repetitive phase shifts.

16. The method of claim 15, including

correlating, by a correlator, the received GPS signals with known reference signals to produce correlation values, and

buffering, by a buffer, a predetermined number of correlation values over a period of time.

17. The method of claim 16, including

detecting, by the processor, a repeating pattern for successively buffered correlation values to detect the repetitive phase shifts, or

computing by the processor, a spectrogram of the buffered correlation values to detect repetitive phase shifts.

18. The method of claim 16, including

predicting, by a GPS adaptive tracking filter, phase error between a clock of the system and a clock of a satellite based on the repetitive phase shifts, and

adjusting the clock of the system to match the clock of the satellite.

19. The method of claim 15, including

computing, by the processor, a stride rate and location of the object over a period of time,

wherein the object is a user in motion and the stride rate is the number of steps per second taken by the user.

20. The method of claim 19, including

displaying the stride rate and location to the user when the system is included in a watch or cellular phone worn by the user, and

displaying the stride rate and location to the user when the system is connected to a personal computer.