LOW AVERAGE VELOCITY PEDESTRIAL MOTION IDENTIFICATION

• US 20120221289A1
• Filed: 02/24/2011
• Published: 08/30/2012
• Est. Priority Date: 02/24/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Burke, John Michael
• Granted Patent: US 8,666,693 B2
• Time in Patent Office: Days
• US Class Current: 702/141
• CPC Class Codes: G01C 22/006 Pedometers
• CPC Class Codes: G01P 13/00 Indicating or recording presence, absence, or direction, of movement electric switches H01H; counting moving objects G06M7/00

Abstract

Systems and methods for identifying a motion state of a mobile device are disclosed. In one embodiment, identifying a motion state of a mobile device using acceleration signals from one or more accelerometers comprises: detecting any pedestrial steps associated with a user of the mobile device during an observation period based on the acceleration signals; determining a maximum number of consecutive pedestrial steps taken during the observation period from the detected pedestrial steps; and declaring a high average velocity motion state or a low average velocity motion state for the observation period based on the determined maximum number of consecutive pedestrial steps.

Claims

1. A method of identifying a motion state of a mobile device using acceleration signals from one or more accelerometers, comprising:

detecting any pedestrial steps associated with a user of the mobile device during an observation period based on the acceleration signals;

determining a maximum number of consecutive pedestrial steps taken during the observation period from the detected pedestrial steps; and

declaring a high average velocity motion state or a low average velocity motion state for the observation period based on the determined maximum number of consecutive pedestrial steps.

2. The method of claim 1, wherein the low average velocity motion state corresponds to fidgeting by the user.

3. The method of claim 1, wherein the high average velocity motion state corresponds to continuous walking or running by the user.

4. The method of claim 1, wherein detecting any pedestrial steps associated with the user comprises:

calculating an acceleration spread pattern from the acceleration signals; and

identifying any peaks in the acceleration spread pattern that meet or exceed a minimum acceleration spread amplitude over a minimum time duration.

5. The method of claim 1, wherein two or more consecutive pedestrial steps satisfy one or more step frequency requirements.

6. The method of claim 5, wherein the one or more step frequency requirements comprise a minimum frequency requirement of about 1.40 steps per second and a maximum frequency requirement of about 2.80 steps per second for successive steps to be deemed consecutive.

7. The method of claim 5, wherein determining the maximum number of consecutive pedestrial steps comprises:

calculating a time interval between successive pedestrial steps for each pedestrial step detected during the observation period;

comparing each time interval to the one or more step frequency requirements; and

identifying a maximum number of successive pedestrial steps detected during the observation period that have a time interval meeting the one or more step frequency requirements.

8. The method of claim 1, wherein the high average velocity motion state is declared for the observation period when the determined maximum number of consecutive pedestrial steps meets or exceeds a threshold, and the low average velocity motion state is declared for the observation period when the determined maximum number of consecutive pedestrial steps is below the threshold.

9. The method of claim 8, wherein the threshold equals about one consecutive pedestrial step per second of the observation period.

10. The method of claim 1, further comprising:

monitoring stationarity of the mobile device based on an acceleration change over time determined from the acceleration signals; and

declaring a stationary motion state for the observation period if the acceleration change over time measured on all accelerometer axes is less than one or more predetermined thresholds during the observation period.

11. The method of claim 1, wherein the observation period is at least one second.

12. The method of claim 1, wherein the observation period is between about two seconds and about ten seconds.

13. The method of claim 1, further comprising repeating the detecting, determining, and declaring over one or more subsequent observation periods.

14. An apparatus for identifying a motion state of a mobile device using acceleration signals from one or more accelerometers, comprising:

a step detector configured to detect any pedestrial steps associated with a user of the mobile device during an observation period based on the acceleration signals; and

a processor configured to determine a maximum number of consecutive pedestrial steps taken during the observation period from the detected pedestrial steps, and to declare a high average velocity motion state or a low average velocity motion state for the observation period based on the determined maximum number of consecutive pedestrial steps.

15. The apparatus of claim 14, wherein the low average velocity motion state corresponds to fidgeting by the user.

16. The apparatus of claim 14, wherein the high average velocity motion state corresponds to continuous walking or running by the user.

17. The apparatus of claim 14, wherein the step detector is configured to detect any pedestrial steps associated with the user by:

calculating an acceleration spread pattern from the acceleration signals; and

identifying any peaks in the acceleration spread pattern that meet or exceed a minimum acceleration spread amplitude over a minimum time duration.

18. The apparatus of claim 14, wherein two or more consecutive pedestrial steps satisfy one or more step frequency requirements.

19. The apparatus of claim 18, wherein the one or more step frequency requirements comprise a minimum frequency requirement of about 1.40 steps per second and a maximum frequency requirement of about 2.80 steps per second for successive steps to be deemed consecutive.

20. The apparatus of claim 18, wherein the processor is configured to determine the maximum number of consecutive pedestrial steps by:

calculating a time interval between successive pedestrial steps for each pedestrial step detected during the observation period;

comparing each time interval to the one or more step frequency requirements; and

identifying a maximum number of successive pedestrial steps detected during the observation period that have a time interval meeting the one or more step frequency requirements.

21. The apparatus of claim 14, wherein the processor is configured to declare the high average velocity motion state for the observation period when the determined maximum number of consecutive pedestrial steps meets or exceeds a threshold, and to declare the low average velocity motion state for the observation period when the determined maximum number of consecutive pedestrial steps is below the threshold.

22. The apparatus of claim 21, wherein the threshold equals about one consecutive pedestrial step per second of the observation period.

23. The apparatus of claim 14, further comprising an any-motion detector configured to:

monitor stationarity of the mobile device based on an acceleration change over time determined from the acceleration signals; and

declaring a stationary motion state for the observation period if the acceleration change over time measured on all accelerometer axes is less than one or more predetermined thresholds during the observation period.

24. The apparatus of claim 14, wherein the observation period is at least one second.

25. The apparatus of claim 14, wherein the observation period is between about two seconds and about ten seconds.

26. The apparatus of claim 14, wherein the step detector and the processor are configured to repeat the detecting, determining, and declaring over one or more subsequent observation periods.

27. An apparatus for identifying a motion state of a mobile device using acceleration signals from one or more accelerometers, comprising:

means for detecting any pedestrial steps associated with a user of the mobile device during an observation period based on the acceleration signals;

means for determining a maximum number of consecutive pedestrial steps taken during the observation period from the detected pedestrial steps; and

means for declaring a high average velocity motion state or a low average velocity motion state for the observation period based on the determined maximum number of consecutive pedestrial steps.

28. The apparatus of claim 27, wherein the low average velocity motion state corresponds to fidgeting by the user.

29. The apparatus of claim 27, wherein the high average velocity motion state corresponds to continuous walking or running by the user.

30. The apparatus of claim 27, wherein the means for detecting any pedestrial steps associated with the user comprises:

means for calculating an acceleration spread pattern from the acceleration signals; and

means for identifying any peaks in the acceleration spread pattern that meet or exceed a minimum acceleration spread amplitude over a minimum time duration.

31. The apparatus of claim 27, wherein two or more consecutive pedestrial steps satisfy one or more step frequency requirements.

32. The apparatus of claim 31, wherein the one or more step frequency requirements comprise a minimum frequency requirement of about 1.40 steps per second and a maximum frequency requirement of about 2.80 steps per second for successive steps to be deemed consecutive.

33. The apparatus of claim 31, wherein the means for determining the maximum number of consecutive pedestrial steps comprises:

means for calculating a time interval between successive pedestrial steps for each pedestrial step detected during the observation period;

means for comparing each time interval to the one or more step frequency requirements; and

means for identifying a maximum number of successive pedestrial steps detected during the observation period that have a time interval meeting the one or more step frequency requirements.

34. The apparatus of claim 27, wherein the high average velocity motion state is declared for the observation period when the determined maximum number of consecutive pedestrial steps meets or exceeds a threshold, and the low average velocity motion state is declared for the observation period when the determined maximum number of consecutive pedestrial steps is below the threshold.

35. The apparatus of claim 34, wherein the threshold equals about one consecutive pedestrial step per second of the observation period.

36. The apparatus of claim 27, further comprising:

means for monitoring stationarity of the mobile device based on an acceleration change over time determined from the acceleration signals; and

means for declaring a stationary motion state for the observation period if the acceleration change over time measured on all accelerometer axes is less than one or more predetermined thresholds during the observation period.

37. The apparatus of claim 27, wherein the observation period is at least one second.

38. The apparatus of claim 27, wherein the observation period is between about two seconds and about ten seconds.

39. The apparatus of claim 27, further comprising means for repeating the detecting, determining, and declaring over one or more subsequent observation periods.

40. A computer-readable medium comprising code, which, when executed by a processor, causes the processor to perform operations for identifying a motion state of a mobile device using acceleration signals from one or more accelerometers, the computer-readable medium comprising:

code for detecting any pedestrial steps associated with a user of the mobile device during an observation period based on the acceleration signals;

code for determining a maximum number of consecutive pedestrial steps taken during the observation period from the detected pedestrial steps; and

code for declaring a high average velocity motion state or a low average velocity motion state for the observation period based on the determined maximum number of consecutive pedestrial steps.

41. The computer-readable medium of claim 40, wherein the low average velocity motion state corresponds to fidgeting by the user.

42. The computer-readable medium of claim 40, wherein the high average velocity motion state corresponds to continuous walking or running by the user.

43. The computer-readable medium of claim 40, wherein the code for detecting any pedestrial steps associated with the user comprises:

code for calculating an acceleration spread pattern from the acceleration signals; and

code for identifying any peaks in the acceleration spread pattern that meet or exceed a minimum acceleration spread amplitude over a minimum time duration.

44. The computer-readable medium of claim 40, wherein two or more consecutive pedestrial steps satisfy one or more step frequency requirements.

45. The computer-readable medium of claim 44, wherein the one or more step frequency requirements comprise a minimum frequency requirement of about 1.40 steps per second and a maximum frequency requirement of about 2.80 steps per second for successive steps to be deemed consecutive.

46. The computer-readable medium of claim 44, wherein the code for determining the maximum number of consecutive pedestrial steps comprises:

code for calculating a time interval between successive pedestrial steps for each pedestrial step detected during the observation period;

code for comparing each time interval to the one or more step frequency requirements; and

code for identifying a maximum number of successive pedestrial steps detected during the observation period that have a time interval meeting the one or more step frequency requirements.

47. The computer-readable medium of claim 40, wherein the high average velocity motion state is declared for the observation period when the determined maximum number of consecutive pedestrial steps meets or exceeds a threshold, and the low average velocity motion state is declared for the observation period when the determined maximum number of consecutive pedestrial steps is below the threshold.

48. The computer-readable medium of claim 47, wherein the threshold equals about one consecutive pedestrial step per second of the observation period.

49. The computer-readable medium of claim 40, further comprising:

code for monitoring stationarity of the mobile device based on an acceleration change over time determined from the acceleration signals; and

code for declaring a stationary motion state for the observation period if the acceleration change over time measured on all accelerometer axes is less than one or more predetermined thresholds during the observation period.

50. The computer-readable medium of claim 40, wherein the observation period is at least one second.

51. The computer-readable medium of claim 40, wherein the observation period is between about two seconds and about ten seconds.

52. The computer-readable medium of claim 40, further comprising code for repeating the detecting, determining, and declaring over one or more subsequent observation periods.