CLIAMS:1. A method for estimation of direction of motion of a user on a mobile device (100), the method comprising:
measuring, by an inertial sensor (112) in the mobile device (100), acceleration values across three axes of the mobile device (100);
removing static bias and noise from the acceleration values to obtain corrected acceleration values across the three axes of the mobile device (100);
filtering the corrected acceleration values using a low-pass filter to determine a direction of gravity;
identifying a plane orthogonal to the direction of gravity, wherein the plane comprises two orthogonal axes, each orthogonal axis being orthogonal to the direction of gravity;
evaluating displacement values along the each of the two orthogonal axes based on a user input for placement of the mobile device (100) with respect to user’s body, and integration of the corrected acceleration values across the two orthogonal axes with respect to time; and
estimating the direction of motion of the user based on a ratio of the displacement values along the two orthogonal axes.
2. The method as claimed in claim 1, wherein the acceleration values are measured in a plurality of time windows of a predetermined time period.
3. The method as claimed in claim 1, wherein the evaluating further comprises scaling the corrected acceleration values by a predetermined value based on the user input regarding placement of the mobile device (100) with respect to the user’s body.
4. The method as claimed in claim 3, wherein the predetermined value is -1 when the mobile device (100) is placed in an upper half of the user’s body, and the predetermined value is +1 when the mobile device (100) is placed in a lower half of the user’s body, along axis of user motion.
5. The method as claimed in claim 1, wherein the filtering comprises:
evaluating value of gravity based on passing the corrected acceleration values through a low-pass filter;
computing absolute value of the gravity; and
comparing the absolute value of the gravity with a predefined tolerance value to filter out gravity components along each of the three axes of the mobile device (100).
6. The method as claimed in claim 5, wherein the predefined tolerance value is 22%.
7. A mobile device (100) for estimation of direction of motion of a user, the mobile device (100) comprising:
a processor (102);
an inertial sensor (112) to capture acceleration signals based on motion of the user;
a direction estimation module (120) coupled to the processor (102), to:
determine direction of gravity based on filtering acceleration values obtained from the acceleration signals using a low-pass filter to identify a plane orthogonal to the direction of gravity, wherein the plane orthogonal to the gravity comprises two orthogonal axes, each orthogonal axis being orthogonal to the direction of gravity;
evaluate displacement values along the two orthogonal axes based on a user input for placement of the mobile device (100) with respect to user’s body, and integration of the acceleration values across the two orthogonal axes with respect to time; and
estimate direction of motion of the user based on a ratio of the displacement values along the two orthogonal axes.
8. The mobile device (100) as claimed in claim 7, wherein the inertial sensor (112) is an accelerometer.
9. The mobile device (100) as claimed in claim 7, wherein the inertial sensor (112) captures the acceleration signals as a data stream in a plurality of time windows of a predetermined time period.
10. The mobile device (100) as claimed in claim 7, wherein the mobile device (100) further comprises a bias removal module (116) coupled to the processor (102), to remove static bias from the acceleration values.
11. The mobile device (100) as claimed in claim 7, wherein the mobile device (100) further comprises a noise removal module (118) coupled to the processor (102), to remove noise from the acceleration values obtained from the acceleration signals.
12. The mobile device (100) as claimed in claim 7, wherein the direction estimation module (120) evaluates the displacement values based on scaling the acceleration values by a predetermined value based on the user input for placement of the mobile device (100) with respect to the user’s body.
13. The mobile device (100) as claimed in claim 12, wherein the predetermined value is -1 if the mobile device (100) is placed in upper half of the user’s body, and the predetermined value is +1 if the mobile device (100) is placed in lower half of the user’s body, along axis of user motion.
14. The mobile device (100) as claimed in claim 8, wherein the direction estimation module (120) determines the direction of gravity based on evaluation of a value of gravity by filtering the acceleration values using a low-pass filter, computation of an absolute value of the gravity, and comparison of the absolute value of the gravity with a predefined tolerance value of the gravity to filter out gravity components along each of the three axes of the mobile device (100).
15. A non-transitory computer readable medium having a set of computer readable instructions that, when executed, cause a mobile device (100) to:
measuring, by an inertial sensor (112) in the mobile device (100), acceleration values across three axes of the mobile device (100);
removing static bias and noise from the acceleration values to obtain corrected acceleration values across the three axes of the mobile device (100);
filtering the corrected acceleration values using a low-pass filter to determine a direction of gravity;
identifying a plane orthogonal to the direction of gravity, wherein the plane comprises two orthogonal axes, each orthogonal axis being orthogonal to the direction of gravity;
evaluating displacement values along the each of the two orthogonal axes based on a user input for placement of the mobile device (100) with respect to user’s body, and integration of the corrected acceleration values across the two orthogonal axes with respect to time; and
estimating the direction of motion of the user based on a ratio of the displacement values along the two orthogonal axes. ,TagSPECI:As Attached