Frequency modulated continuous wave radar device, and object detection method using continuous wave thereof

1. A frequency modulated continuous wave (FMCW) radar device, comprising:

a continuous wave (CW) signal generator configured to generate a transmit (Tx) CW signal;

a radio frequency (RF) transmitter configured to transmit the generated Tx CW signal as an RF signal through a Tx antenna;

an RF receiver configured to receive a reflected CW signal which is reflected and returned from a forward object after the Tx CW signal is transmitted;

a target detector configured to extract speed and angle using a frequency difference between the Tx CW signal and the reflected CW signal, and detect an approaching target; and

a detection controller configured to control the RF transmitter to transmit the Tx CW signal as a signal having a triangular waveform in a time-frequency graph and to additionally transmit the Tx CW signal as a signal having a crossbar waveform at a predetermined frequency for a predetermined time, extract speed and angle from the reflected CW signal having a crossbar waveform so as to detect the approaching target, when the sign of the target speed extracted from the reflected CW signal having a triangular waveform is negative (−), and extract speed and angle from the reflected CW signal having the triangular waveform so as to detect the target, when the sign of the target speed extracted from the reflected CW signal having the triangular waveform is not negative (−).

2. The FMCW radar device according to claim 1 , wherein when an in-phase (I) channel and a quadrature (Q) channel exist for each channel, the target detector extracts the sign of the target speed through phase information of the reflected CW signal.

3. The FMCW radar device according to claim 1 , wherein the CW signal generator comprises a direct digital synthesizer (DDS) and a local oscillator for generating the Tx CW signal having a triangular waveform and the Tx CW signal having a crossbar waveform.

4. The FMCW radar device of claim 1 , wherein the RF transmitter is configured to transmit the signal having triangular waveform and the signal having the crossbar waveform which has a frequency between minimum and maximum frequencies of the triangular waveform.

5. An object detection method using continuous waves of an FMCW radar device including a CW signal generator, an RF transmitter, an RF receiver, a target detector, and a detection controller, the object detection method comprising:

generating, by the CW signal generator, a Tx CW signal having a triangular waveform;

transmitting, by the detection controller, the Tx CW signal having a triangular waveform as an RF signal through the RF transmitter;

generating, by the CW signal generator, a Tx CW signal having a crossbar waveform;

transmitting, by the detection controller, the Tx CW signal having a crossbar waveform as an RF signal through the RF transmitter;

sequentially receiving, by the RF receiver, a triangular-waveform reflected CW signal and a crossbar-waveform reflected CW signal which are reflected and returned after the Tx CW signals are transmitted;

extracting, by the target detector, the sign of target speed from the reflected CW signal having a triangular waveform;

extracting, by the target detector, speed and angle from the reflected CW signal having a crossbar waveform to detect an approaching target, when the sign of the target speed is negative (−); and

extracting, by the target detector, speed and angle from the reflected CW signal having the triangular waveform to detect a target, when the sign of the target speed is not negative (−).

6. The object detection method according to claim 5 , wherein in the extracting of the sign of the target speed,

the target detector extracts the sign of the target speed through phase information of the reflected CW signal, when an in-phase (I) channel and a quadrature (Q) channel exist for each channel.

7. The object detection method of claim 5 , wherein the RF transmitter transmits the signal having triangular waveform and the signal having the crossbar waveform which has a frequency between minimum and maximum frequencies of the triangular waveform.