Method and device for measuring the progress of a moving person
View Patent ↗The invention relates to measuring devices to be used in physical measuring, and more particularly, to a method and a device for measuring the progress of a moving person. In the solution according to the invention the quantities describing the progress of the moving person are being calculated based on step cycle-specific acceleration stage characteristic accelerations a+ and step cycle-specific braking stage characteristic acceleration a− obtained from acceleration values measured by means of an acceleration sensor, and on the measured time. The invention aims at providing a solution, better and simpler than prior solutions, for measuring the progress of a moving person, which solution is applicable for use in a multitude of measuring solutions for ways of locomotion of various types.
1. A method for displaying progress of a moving person, comprising:
measuring acceleration values of cyclic motion of locomotion of the moving person by means of an acceleration sensor;
determining step data as a function of step cycle-specific acceleration stage characteristic accelerations a+ and/or braking stage characteristic accelerations a− obtained from the acceleration values measured by means of the acceleration sensor;
obtaining compass readings of the moving person from a magnetometer; and
determining a traveled route of the moving person by means of the step data and the compass readings,
wherein the step data includes an acceleration stage characteristic acceleration a+ obtained as a mean value of a digitally filtered acceleration sensor signal a out over a time selected during a positive half-cycle of the step cycle, and a braking stage characteristic acceleration a− obtained as a mean value of a digitally filtered acceleration sensor signal a out over a time selected during a negative half-cycle of the step cycle,
wherein the method further comprises displaying, in a display unit, the traveled route of the moving person, and guiding the moving person via step by step navigation using the traveled route.
2. The method according to claim 1 , wherein a function used in digital filtering is:
a out =a in /√{square root over ([1+( f/f 0 ) 2 ])},
where f is the frequency and f 0 is a suitably selected boundary frequency.
3. The method according to claim 1 , wherein the function used in the digital filtering is digital weighing:
a out ( n )=(1 −k )* a out ( n− 1)+ a in *k,
where n indicates the n:th sample and k is the weighting factor.
4. The method according to claim 1 , wherein speed v of the locomotion is calculated as a function of the step cycle-specific acceleration stage characteristic acceleration values a+ and/or a− as follows:
v=f ( a +)= k*|a +|, or
v=f ( a −)= k*|a−|,
where k is a constant.
5. The method according to claim 1 , wherein for calculating further quantities describing the progress of the moving person, the time used up in one pair of steps Δt pos is obtained as a time interval between two equivalent points, such as a maximum, a minimum, or a point of exceeding or falling below a certain value, on an acceleration graph given by the measured acceleration values.
6. The method according to claim 5 , wherein the length of a step s step or the length of a pair of steps s pos is calculated using the formula:
s
step
=
1
2
*
v
*
Δ
t
pos
or
s
pos
=
v
*
Δ
t
pos
.
7. The method according to claim 6 , wherein a step count n is calculated on the basis of the number n of equivalent points, such as a maximum, a minimum, or a point of exceeding or falling below a certain value, on the acceleration graph given by the measured acceleration values.
8. The method according to claim 6 , wherein the distance covered s is calculated as the sum of the lengths of the steps or the pairs of steps:
s
=
2
*
∑
i
=
1
n
s
step
(
i
)
or
s
=
∑
i
=
1
n
s
pos
(
i
)
.
9. The method according to claim 5 , wherein the rate of pairs of steps f pos , or the step rate f step , are calculated using the formula:
f pos =1/Δ t pos or f step =2/Δ t pos .
10. The method according to claim 1 , wherein the ways of progress comprises walking, running, and skiing, and wherein the ways of progress are distinguished based on acceleration maximum and minimum, the characteristic acceleration values a+ and a− and/or the step rate.
11. The method according to claim 10 , wherein an individual calibration for each way of progress is made.
12. The method according to claim 1 , wherein the method is applied for use in step-by-step navigation.
13. A device for displaying progress of a moving person, comprising:
a display unit; and
a measuring unit that comprises an acceleration sensor, an analysis and diagnostic unit, and a magnetometer,
wherein the acceleration sensor is configured to measure acceleration values of cyclic motion of locomotion of the moving person,
wherein the magnetometer is configured to obtain compass readings of the moving person,
wherein the analysis and diagnostic unit is configured to calculate step data as a function of step-cycle-specific acceleration stage characteristic accelerations a+ and braking stage characteristic accelerations a− obtained from acceleration values measured by the acceleration sensor during a step cycle,
wherein the analysis and diagnostic unit is configured to determine the step data as a step-cycle-specific acceleration stage characteristic acceleration a+ as a mean value of a digitally filtered acceleration sensor signal a out over a time selected during a positive half-cycle of the step cycle, and a braking stage characteristic acceleration a− as a mean value of a digitally filtered acceleration sensor signal a out over a time selected during a negative half-cycle of the step cycle,
wherein the analysis and diagnostic unit is configured to determine a traveled route of the moving person by means of the step data and the compass readings,
wherein the display unit is configured to display the traveled route of the moving person, and to guide the moving person via step by step navigation using the traveled route.
14. The device according to claim 13 , wherein the device is configured to use the following function in the digital filtering:
a out =a in /√{square root over ([1+( f/f 0 ) 2 ])},
where f is the frequency and f 0 is a suitably selected boundary frequency.
15. The device according to claim 13 , wherein the device is configured to use this digital weighting function in the digital filtering:
a out ( n )=(1− k )* a out ( n− 1)+ a in *k
where n indicates the n:th sample and k is the weighting factor.
16. The device according to claim 13 , wherein the device is configured to calculate the speed v based on the characteristic accelerations a+ and/or a− as follows:
v=f ( a +)= k*|a +|, or
v=f ( a −)= k*|a−|,
where k is a constant.
17. The device according to claim 13 , wherein the device is configured to determine the time used up in one pair of steps Δt pos as a time interval between two equivalent points, such as a maximum, a minimum, or a point of exceeding or falling below a certain value, on an acceleration graph given by the measured acceleration values.
18. The device according to claim 17 , wherein the device is configured to calculate the length of a step s step or the length of one pair of steps s pos using the formula:
s
step
=
1
2
*
v
*
Δ
t
pos
or
s
pos
=
v
*
Δ
t
pos
.
19. The device according to claim 18 , wherein the device is configured to calculate a step count n on the basis of the number n of equivalent points, such as a maximum, a minimum, or a point of exceeding or falling below a certain value, on the acceleration graph given by the measured acceleration values.
20. The device according to claim 18 , wherein the device is configured to calculate a distance covered s as the sum of the lengths of the steps or of the pairs of steps:
s
=
2
*
∑
i
=
1
n
s
step
(
i
)
or
s
=
∑
i
=
1
n
s
pos
(
i
)
.
21. The device according to claim 17 , wherein the device is configured to calculate the rate of pairs of steps f pos or the step rate f step using the formula:
f pos =1/Δ t pos or f step =2/Δ t pos
22. The device according to claim 13 , wherein the device is configured to distinguish between ways of progress comprising walking, running, and skiing, and wherein the ways of progress are distinguished based on acceleration maximum and minimum, the characteristic acceleration values a+ and a− and/or the step rate.
23. The device according to claim 22 , wherein the device is configured to make an individual calibration for each way of progress.
24. The device according to claim 13 , wherein the device is configured to be used in step-by-step navigation.
25. The device according to claim 24 , wherein the device is configured to cooperate with an altimeter and/or satellite navigation devices.
26. The device according to claim 24 , wherein the device is configured to receive and/or utilize data in map databases and/or terrain inclination data.
27. A piece of footwear, wherein the piece of footwear comprises a device according to claim 13 .
28. A system for measuring the progress of a moving person, wherein the system comprises the device according to claim 13 .