Estimating velocity in a horizontal or vertical direction from acceleration measurements
First Claim
1. A method of determining an estimate of the velocity of a fall detection device in a horizontal or vertical direction, the method comprising:
- obtaining with an accelerometer of the device acceleration measurements of an acceleration acting on the device in three dimensions;
using, by a processor of the device, a first filter and the obtained acceleration measurements to estimate acceleration due to gravity;
estimating with the processor the acceleration acting in a horizontal or vertical direction due to motion of the device using the estimated acceleration due to gravity;
integrating with the processor the estimate of the acceleration acting in said direction due to motion of the device to give an estimate of the velocity in said direction; and
using, by the processor, a second filter to remove offset and/or drift from the velocity to give a filtered velocity;
wherein at least one of the first filter and second filter is a non-linear filter.
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Abstract
There is provided a method of determining an estimate of the velocity of a device in a horizontal or vertical direction, the method comprising obtaining measurements of the acceleration acting on the device in three dimensions; using a first filter and the obtained measurements to estimate acceleration due to gravity; estimating the acceleration acting in a horizontal or vertical direction due to motion of the device using the estimated acceleration due to gravity; integrating the estimate of the acceleration acting in said direction due to motion of the device to give an estimate of velocity in said direction; and using a second filter to remove offset and/or drift from the velocity to give a filtered velocity; wherein at least one of the first filter and second filter is a non-linear filter. An apparatus configured to operate according to the above method is also provided.
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Citations
15 Claims
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1. A method of determining an estimate of the velocity of a fall detection device in a horizontal or vertical direction, the method comprising:
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obtaining with an accelerometer of the device acceleration measurements of an acceleration acting on the device in three dimensions; using, by a processor of the device, a first filter and the obtained acceleration measurements to estimate acceleration due to gravity; estimating with the processor the acceleration acting in a horizontal or vertical direction due to motion of the device using the estimated acceleration due to gravity; integrating with the processor the estimate of the acceleration acting in said direction due to motion of the device to give an estimate of the velocity in said direction; and using, by the processor, a second filter to remove offset and/or drift from the velocity to give a filtered velocity; wherein at least one of the first filter and second filter is a non-linear filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 15)
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12. An apparatus, comprising:
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processing means that are configured to; receive measurements of an acceleration acting on a device in three-dimensions from acquired with an accelerometer of the apparatus; use, with a processor of the apparatus, a first filter and the measurements of the acceleration to estimate acceleration due to gravity; estimate with the processor the acceleration acting in a horizontal or vertical direction due to motion of the device using the estimated acceleration due to gravity; integrate with the processor the estimate of the acceleration acting in said direction due to motion of the device to give an estimate of velocity in said direction; and use, with the processor, a second filter to remove offset and/or drift from the velocity to give a filtered velocity; wherein at least one of the first filter and second filter used by the processing means is a non-linear filter. - View Dependent Claims (13, 14)
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Specification