Circuitry and method for reducing echo walk error in a time-of-flight laser distance device
US9874441B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 16, 2014 |
| Grant date | Jan 23, 2018 |
| Priority date | — |
| Expiry date | Jan 29, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K5/1534
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A time-of-flight laser distance device includes a laser transmitter, a laser pulse return detector to receive reflected laser pulses, and comparators with respective first and second trip levels. A preliminary distance to a target is based on a linear ramp as a function of lapsed time from laser pulse generation through an effective time period wherein an associated return pulse is detected. Time-of-flight values associated with a leading edge of the return pulse are obtained at each of the first and second trip levels. A time difference is determined between the obtained values, and a correction factor is applied with respect to the preliminary measured distance based on the determined time difference. A dual ADC may be used wherein the leading edge of the return pulse is calculated by measuring a slope associated with the time-of-flight values and extrapolating a slope origin to a zero crossing point.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.