Step filter for estimating distance in a time-of-flight ranging system
US9194943B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 11, 2012 |
| Grant date | Nov 24, 2015 |
| Priority date | — |
| Expiry date | May 6, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S11/08
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A ranging system includes a time of flight subsystem including circuitry incorporated in a mobile node and a base station for generating a TOF signal between the mobile node and the base station, measuring the time taken for transmission of the TOF signal, and generating a TOF distance signal based on the measured time. An accelerometer, mounted in the mobile node, generates an accelerometer signal. A distance filter generates the distance estimate. The filter is configured to (i) initialize the value of a distance estimate signal based on the TOF distance signal, (ii) detect a human step based on variances in the accelerometer signal, and (iii) change the value of the distance estimate signal by a predetermined quantum only upon detection of the human step, the change being positive or negative depending on a direction of the TOF distance signal relative to the distance estimate signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.