ULTRASONIC DISTANCE AND VELOCITY MEASUREMENT FOR MOVING OBJECTS USING CYCLES OF MSEQUENCE MODULATED SIGNALS

摘要

Pulse compression using M-sequence modulated signals can improve the SNR of reflected echo and distance resolution in the pulse-echo method. In the case of a moving object, however, the echo is modulated due to the Doppler effect. The Doppler-shifted M-sequence modulated signal cannot be correlated with the reference signal, which is corresponding to the transmitted M-sequence modulated signal. Therefore, Doppler velocity estimation from spectral pattern analysis of cyclic M-sequence modulated signals before the correlation process and cross correlation of the received signal with the Doppler-shifted reference signals has been proposed. In this paper, a principle of the proposed Doppler velocity estimation is described. Then, estimated Doppler velocities are evaluated by computer simulations and experiments.