SPEED MEASURING METHOD AND SPEED MEASURING DEVICE BY LASER DOPPLER SYSTEM

摘要

PROBLEM TO BE SOLVED: To improve measurement accuracy without complicating a structure, detect a signal even when the reflected signal of a measured object is small, and improve the reliability of the measured result. ;SOLUTION: This device is provided with multiple band-pass filters(BPF) 5-1 through 5-n receiving signals from a transceiver 21 and having a continuous pass bandwidth 10, a switching circuit 8 selectively outputting one of the signals passing the BPF 5-1 through 5-n, an analog/digital converter circuit (A/D) 13 converting the signal outputted from the switching circuit 8 into a digital signal, a coherent integrating circuit 14 analyzing the signal outputted from the A/D 13 into the frequency spectrum having a narrow bandwidth (b), a noncoherent integrating circuit 15 adding signals for each frequency, and a constant false alarm probability detecting circuit (CFAR) 16 automatically detecting the target signal at a constant false detection rate. The number of the BPF 5-1 through 5-n can be reduced, and a structure is simplified. The signal-to-noise power ratio is improved, and the reflected signal can be detected even when it is small.;COPYRIGHT: (C)1997,JPO