Simultaneous Range And Velocity Measurement By Vehicle Laser Radar Based On Pseudo-random Noise Code Modulation

The simultaneous measurement of target distance and velocity in road environment is the basis of path planning for autonomous driving vehicles.At present,the sensors used to measure these two parameters are mainly millimeter wave radar and laser radar.The millimeter wave radar uses frequency modulation continuous wave to have realized the synchronous measurement of target distance and velocity,but the space resolution of millimeter wave radar is poor,so it cannot clearly image the driving scene.Moreover,that the measurement waveform uses continuous wave mode causes that the measurement performance of millimeter wave radar in complex scene greatly reduces.When multiple targets appear in the same beam,the way to use pulse is a better choice.This paper,as a preliminary study of "the method of target distance and velocity measurement in complex road environment",aims to design a method based on pulse sequence modulation to realize measuring the distance and speed of the road target simultaneously by laser radar.This paper designed a single detector pulse Doppler laser radar system structure diagram,proposed a method modulating by pseudo random code,calculated the target distance through the correlation function of pseudo random modulation code and photoelectric converter,and the measurement sensitivity is insensitive to laser radar echo frequency and phase.In the process of echo signal processing,this paper proposed the amplitude correction of Doppler signal,then used the unequal interval sampling Fourier frequency spectrum analysis method to calculate the Doppler frequency,then calculated the target distance information according to the Doppler effect,and its radial velocity error is lower than 1m/s.The results show that the method presented in this paper can be used to measure the distance and velocity of the road target simultaneously.