Granted Patent B2

US 12,596,174 · App. 18/083,934 · Granted Apr 7, 2026

Inventors: Hiroki Goto (Tokyo, JP); Masashi Mitsumoto (Tokyo, JP)

Assignee: MITSUBISHI ELECTRIC CORPORATION

G01S7/356G01S13/34

Abstract

Claims (43)

1 . A distance measurement device comprising:

processing circuitry

to divide a digital signal into N digital signals (N is an integer equal to or greater than 2), the digital signal showing interference light between reflected light which is received from a distance measurement target by applying part of frequency swept light whose frequency varies with time to the distance measurement target, and reference light which is the remaining part of the frequency swept light;

to shift a frequency of each of the N digital signals after distribution by a shift amount, the plurality of shift amounts of frequencies for the corresponding N digital signals being different from each other;

to perform a Fourier transform on each of the N digital signals after frequency shift; and

to determine a frequency component related to the distance measurement target, out of a plurality of frequency components contained in all of N signals after the Fourier transform,

to determine a shift amount from the plurality of shift amounts after the Fourier transform, the determined shift amount being related to a signal which includes the determined frequency component and is associated with one of the N digital signals, and

to calculate a distance from the distance measurement device to the distance measurement target from a sum of a frequency of the determined frequency component and the determined shift amount.

2 . The distance measurement device according to claim 1 , wherein

the processing circuitry includes N frequency shift processing circuits to respectively shift frequencies of the N digital signals after the distribution, and

each of the N frequency shift processing circuits shifts a frequency of a digital signal different from those by other frequency shift processing circuits by a shift amount different from those of the other frequency shift processing circuits.

3 . The distance measurement device according to claim 2 , wherein

the processing circuitry includes N Fourier transform processing circuits to respectively perform Fourier transforms on the N digital signals after the frequency shift by the N frequency shift processing circuits.

4 . The distance measurement device according to claim 3 , wherein

the processing circuitry:

to determine the frequency component related to the distance measurement target, out of a plurality of frequency components contained in all of signals after Fourier transforms by the N Fourier transform processing circuits;

to determine the shift amount related to the signal after the Fourier transform which includes the determined frequency component, out of the plurality of shift amounts which are used for the shift of the frequency; and

to calculate the distance from the distance measurement device to the distance measurement target from the sum of the frequency of the determined frequency component, and the determined shift amount.

5 . The distance measurement device according to claim 1 , wherein

the distance measurement device includes a calculator, and

the calculator shifts N times a frequency of the digital signal showing the interference light by shift amounts that are different from each other, and performs a Fourier transform on each of digital signals after the frequency shift.

6 . A distance measurement method comprising:

dividing a digital signal into N digital signals (N is an integer equal to or greater than 2), the digital signal showing interference light between reflected light which is received from a distance measurement target by applying part of frequency swept light whose frequency varies with time to the distance measurement target, and reference light which is the remaining part of the frequency swept light;

shifting a frequency of each of the N digital signals after distribution by a shift amount, the plurality of shift amounts of frequencies for the corresponding N digital signals being different from each other;

performing a Fourier transform on each of the N digital signals after frequency shift; and

determining a frequency component related to the distance measurement target, out of a plurality of frequency components contained in all of N signals after the Fourier transform,

determining a shift amount from the plurality of shift amounts after the Fourier transform, the determined shift amount being related to a signal which includes the determined frequency component and is associated with one of the N digital signals, and

calculating a distance from the distance measurement device to the distance measurement target from a sum of a frequency of the determined frequency component and the determined shift amount.

7 . A radar device comprising:

the distance measurement device according to claim 1 ; and

an optical transmitter and receiver to apply the part of the frequency swept light whose frequency varies with time to the distance measurement target, and to, after that, receive the reflected light which is frequency swept light reflected by the distance measurement target and to output the digital signal showing the interference light between the reflected light and reference light which is the remaining part of the frequency swept light to the distance measurement device.

8 . A radar device comprising:

the distance measurement device according to claim 2 ; and

an optical transmitter and receiver to apply the part of the frequency swept light whose frequency varies with time to the distance measurement target, and to, after that, receive the reflected light which is frequency swept light reflected by the distance measurement target and to output the digital signal showing the interference light between the reflected light and reference light which is the remaining part of the frequency swept light to the distance measurement device.

9 . A radar device comprising:

the distance measurement device according to claim 3 ; and

an optical transmitter and receiver to apply the part of the frequency swept light whose frequency varies with time to the distance measurement target, and to, after that, receive the reflected light which is frequency swept light reflected by the distance measurement target and to output the digital signal showing the interference light between the reflected light and reference light which is the remaining part of the frequency swept light to the distance measurement device.

10 . A radar device comprising:

the distance measurement device according to claim 4 ; and

an optical transmitter and receiver to apply the part of the frequency swept light whose frequency varies with time to the distance measurement target, and to, after that, receive the reflected light which is frequency swept light reflected by the distance measurement target and to output the digital signal showing the interference light between the reflected light and reference light which is the remaining part of the frequency swept light to the distance measurement device.

11 . A radar device comprising:

the distance measurement device according to claim 5 ; and

an optical transmitter and receiver to apply the part of the frequency swept light whose frequency varies with time to the distance measurement target, and to, after that, receive the reflected light which is frequency swept light reflected by the distance measurement target and to output the digital signal showing the interference light between the reflected light and reference light which is the remaining part of the frequency swept light to the distance measurement device.

Assignments (1)

Continuity (2)

References Cited (11)