| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a radar apparatus by which a speed can be detected with good accuracy even when a relative velocity is nearly 0. SOLUTION: A trigger-pulse generation circuit 3 frequency-divides a reference signal so as to generate a sending timing signal. A radar head 10 sends out a transmitting signal in a prescribed time width from a transmitting-receiving antenna on the basis of the sending timing signal from the trigger-pulse generation circuit 3. A received signal is mixed with an oscillation signal whose frequency is byαsmaller than the reference signal, and it is frequency-converted. Thereby, an asynchronous frequency componentαis mixed with the sending timing signal. In a signal processing part 20, the receiving signal which is frequency-converted is sampled. On the basis of the receiving signal and on the basis of history data in the past, the amplitude change frequency of a sample value is found. At this time, since the asynchronous frequency is detected as a pseudo Doppler frequency, a Doppler frequency does not become 0 even when a relative speed is 0, and the Doppler frequency can be detected without being influenced by a noise at a low frequency. A speed can be detected with good accuracy.</p> |
