Radar apparatus and distance measurement method

A radar apparatus comprising:

• a transmitting unit comprising an antenna and configured to transmit a signal having a constant frequency or a continuous wave signal obtained by modulating the signal;
• a receiving unit comprising one or more receiving antennas and configured to receive a reflected wave that is the continuous wave signal reflected by an object;
• a mixer configured to mix the received reflected wave and the continuous wave signal to obtain a beat signal;
• a frequency estimation unit comprising an analog-digital converter and configured to estimate a frequency of the beat signal;
• and
• a distance estimation unit configured to estimate a distance to the object based on the frequency of the beat signal,
• wherein estimating the frequency of the beat signal comprises:
• obtaining a sequence of discrete signal values by sampling the beat signal at predetermined intervals,
• determining an autoregressive model represented by a linear combination of the sequence of discrete signal values using a set of autoregressive coefficients,
• calculating each autoregressive coefficient of the autoregressive model, wherein the calculated autoregressive coefficients minimize the linear combination, and
• estimating the frequency of the beat signal using a base frequency that is based on a pole of the autoregressive model.