Range measurement device, range measurement method, and storage medium

A range measurement method executed by a computer, the method comprising:

• transmitting, by a transmitter of a range measurement device, toward targets, pulse waves which have been frequency modulated;
• receiving, by a receiver of the range measurement device, echo waves which are the pulse waves reflected by the targets and returned from the targets;
• obtaining a signal by inverse correlating in frequency domain a second baseband signal with a first baseband signal;
• fitting the signal with exponential functions whose argument have real parts and imaginary parts using Prony method;
• removing a part of exponential functions which have greater absolute values of the real parts than a prescribed value, as noise, among the exponential functions obtained by fitting the signal;
• acquiring values of amplitudes and values of the imaginary parts from the exponential functions from which the noise has been removed;
• acquiring values of relative amplitudes of the targets and values of ranges of the targets from the range measurement device, from exponential function information including the values of the amplitudes and the values of the imaginary parts that have been acquired, and updating the values of ranges of the targets from the range measurement device,
• wherein the first baseband signal is a baseband signal converted from the pulse waves,
• wherein the second baseband signal is a baseband signal converted from the echo waves, and wherein the range measurement method improves measurement accuracy and resolution, and to obtain a number of targets, the values of ranges of the targets, and the value of the relative amplitude without being limited to a value determined from a frequency change width of transmitted waves.

A computer-readable, non-transitory, storage medium storing a program for causing a computer to:

• transmit, by a transmitter of a range measurement device, toward targets, pulse waves which have been frequency modulated;
• receive, by a receiver of the range measurement device, echo waves which are the pulse waves reflected by the targets and returned from the targets;
• obtain a signal by inverse correlating in frequency domain a second baseband signal with a first baseband signal;
• fit the signal with exponential functions whose arguments have real parts and imaginary parts using Prony method;
• remove a part of exponential functions which have greater absolute values of the real parts than a prescribed value, as noise, among the exponential functions by fitting the signal;
• acquire values of amplitudes and values of the imaginary parts from the exponential functions from which the noise has been removed;
• acquire values of relative amplitudes of the targets and values of ranges of the targets from the range measurement device, from exponential function information including the values of the amplitudes and the values of the imaginary parts that have been acquired, and update the values of ranges of the targets from the range measurement device,
• wherein the first baseband signal is a baseband signal converted from the pulse waves,
• wherein the second baseband signal is a baseband signal converted from the echo waves, and wherein the program causes the computer to improve measurement accuracy and resolution, and to obtain a number of targets, the values of ranges of the targets, and the value of the relative amplitude without being limited to a value determined from a frequency change width of transmitted waves.