Patent ID: 11899097
Assignee: TOSHIBA ELECTRONIC DEVICES & STORAGE CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 15:
16. The distance measurement method according to claim 11, wherein
the first device samples the second phase information for one period of the second demodulated signal or longer,
the second device performs, twice or more, sampling of the first phase information for one period of the first demodulated signal or longer,
two samples, phase change of which is maximized through subtraction of a temporally previous sample of a sample are obtained for each of the second demodulated signal and the first demodulated signal,
an elapsed time tb1 of the second device from a time point at which the reception of the first demodulated signal is started, to a time point at which the reception of the first demodulated signal is sampled is calculated by using three continuous samples including the two samples of the first demodulated signal for a first time,
an elapsed time ta1 of the first device from a time point at which the reception of the second demodulated signal is started, to a time point at which the second demodulated signal is sampled is calculated by using three continuous samples including the two samples of the second demodulated signal,
an elapsed time tb2 of the second device from a time point at which the reception of the first demodulated signal is started, to a time point at which the first demodulated signal is sampled is calculated by using three continuous samples including the two samples of the first demodulated signal for a second time,
a first flight time tx,err1 including error is calculated by

tx,err1=(TS−ta1−tb1)/2

where TS represents the first or second sampling period,
a second flight time tx,err2 including error is calculated by

tx,err2=(TS−ta1−tb2)/2

an average flight time is calculated by averaging the first flight time tx,err1 and the second flight time tx,err2, and
the distance is calculated based on the average flight time.