Distance measurement device and distance measurement method

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.