Distance measurement device and distance measurement method

Patent metadata

Field	Value
Publication number	US-11899097-B2
Application number	US-202117200486-A
Country	US
Kind code	B2
Filing date	Mar 12, 2021
Priority date	Sep 24, 2020
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

A distance measurement device of an embodiment includes a first device including a first reference signal source and a first transmitter-receiver, a second device including a second reference signal source and a second transmitter-receiver, and a calculation unit configured to calculate a distance between the first device and the second device. One of a first distance measurement signal and a second distance measurement signal is transmitted once or more, and another is transmitted twice or more. The calculation unit calculates the distance based on a total of three or more pieces of first phase information and second phase information acquired through transmission of the distance measurement signals three times or more in total, a first sampling period based on a first reference signal, and a second sampling period based on a second reference signal.

First claim

What is claimed is:

1. A distance measurement device comprising:
a first device including
a first reference signal source configured to generate a first reference signal, and
a first transmitter-receiver configured to transmit a modulated first distance measurement signal, receive a modulated second distance measurement signal, obtain a second demodulated signal through demodulation, and acquire second phase information of the second demodulated signal in a first sampling period based on the first reference signal;

a second device including
a second reference signal source configured to operate independently from the first reference signal source and generate a second reference signal, and
a second transmitter-receiver configured to transmit the second distance measurement signal, receive the first distance measurement signal, obtain a first demodulated signal through demodulation, and acquire first phase information of the first demodulated signal in a second sampling period based on the second reference signal; and

a calculation unit configured to calculate a distance between the first device and the second device based on the first phase information and the second phase information, wherein
one of the first distance measurement signal and the second distance measurement signal is transmitted once or more, and another of the first distance measurement signal and the second distance measurement signal is transmitted twice or more, and
the calculation unit calculates the distance based on a total of three or more pieces of the first phase information and the second phase information acquired through transmission of the first distance measurement signal and the second distance measurement signal three times or more in total, the first sampling period, and the second sampling period.

2. The distance measurement device according to claim 1 , wherein when calculating the distance, the calculation unit
corrects a time offset between the first sampling period and the second sampling period based on first phase information and second phase information obtained through loop-back transmission of the first distance measurement signal and the second distance measurement signal, and
corrects a frequency offset between the first sampling period and the second sampling period based on the first phase information and the second phase information obtained through the loop-back transmission and at least one of first phase information and second phase information obtained through transmission one or more times of at least one of the first distance measurement signal and the second distance measurement signal other than the loop-back transmission.

3. The distance measurement device according to claim 2 , wherein the calculation unit calculates the distance based on two or more pieces of the first phase information and one or more pieces of the second phase information obtained through a distance measurement sequence in which
the first transmitter-receiver transmits the first distance measurement signal, and the second transmitter-receiver receives the first distance measurement signal,
the second transmitter-receiver transmits the second distance measurement signal, and the first transmitter-receiver receives the second distance measurement signal, and
the first transmitter-receiver transmits the first distance measurement signal, and the second transmitter-receiver receives the first distance measurement signal.

4. The distance measurement device according to claim 2 , wherein the calculation unit calculates the distance based on two or more pieces of the first phase information and two or more pieces of the second phase information obtained through a distance measurement sequence in which
the first transmitter-receiver transmits the first distance measurement signal, and the second transmitter-receiver receives the first distance measurement signal,
the second transmitter-receiver transmits the second distance measurement signal, and the first transmitter-receiver receives the second distance measurement signal,
the second transmitter-receiver transmits the second distance measurement signal, and the first transmitter-receiver receives the second distance measurement signal, and
the first transmitter-receiver transmits the first distance measurement signal, and the second transmitter-receiver receives the first distance measurement signal.

5. The distance measurement device according to claim 2 , wherein the calculation unit calculates the distance based on two or more pieces of the first phase information and one or more pieces of the second phase information obtained through a distance measurement sequence in which
the first transmitter-receiver transmits the first distance measurement signal, and the second transmitter-receiver receives the first distance measurement signal,
the second transmitter-receiver transmits the second distance measurement signal, and the first transmitter-receiver receives the second distance measurement signal, and
the first transmitter-receiver sets a phase of the received second distance measurement signal as a phase at transmission start and transmits the first distance measurement signal, and the second transmitter-receiver receives the first distance measurement signal.

6. The distance measurement device according to claim 1 , wherein
the first transmitter-receiver samples the second phase information for one period of the second demodulated signal or longer,
the second transmitter-receiver performs, twice or more, sampling of the first phase information for one period of the first demodulated signal or longer, and
the calculation unit
obtains, for each of the second demodulated signal and the first demodulated signal, two samples, phase change of which is maximized through subtraction of a temporally previous sample of a sample,
calculates, by using three continuous samples including the two samples of the first demodulated signal for a first time, an elapsed time t b1 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 obtained,
calculates, by using three continuous samples including the two samples of the second demodulated signal, an elapsed time t a1 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 obtained,
calculates, by using three continuous samples including the two samples of the first demodulated signal for a second time, an elapsed time t b2 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 obtained,
calculates a first flight time t x,err1 including error by
t x,err1 =( T S −t a1 −t b1 )/2

where T S represents the first or second sampling period,
calculates a second flight time t x,err2 including error by
t x,err2 =( T S −t a1 −t b2 )/2

calculates an average flight time by averaging the first flight time t x,err1 and the second flight time t x,err2 and
calculates the distance based on the average flight time.

7. The distance measurement device according to claim 6 , wherein
the first transmitter-receiver performs, twice or more, sampling of the second phase information for one period of the second demodulated signal or longer, and
the calculation unit
calculates, by using three continuous samples including the two samples of the second demodulated signal for a second time, an elapsed time t a2 of the first device from a time point at which the reception of the second demodulated signal is sta

Assignees

• Toshiba Kk
• Toshiba Electronic Devices & Storage Corp

Inventors

• Ootaka Shoji
• Nishikawa Masaki
• Nonin Katsuya
• Yoshida Hiroshi
• Oshiro Masayoshi

Classifications

• G01S13/765 Primary

  with exchange of information between interrogator and responder · CPC title