In-Car Doppler Laser Radar For Range And Speed Measurement

Range and speed measurement is an important part of road environment sensing for autonomous driving vehicles,which provides the information that is required for path planning safely and obstacle avoiding actively.However,their working environments have becoming increasingly complex with the growing types of autonomous driving vehicles,including vehicles,pedestrians and traffic assigns in structured and unstructured roads.The methods for range and speed measurement based on traditional radar signal processing have various performance limitations such as miss detection and crosstalk in multi-agent robot driving environments,causing them not competent to the task of environment sensing that are faced by modern unmanned driving.This paper will deal with complex environments that include multi-targets with different reflection ratio,with the main emphasis on studying the method for range and speed measurement to achieve the purpose of environment modeling,evaluating its measuring performance and providing necessary information for realizing unmanned driving.In this paper,firstly,a pulsed-Doppler laser radar based on pseudo-random noise code modulation was proposed.Then,a new method of discrete Fourier transform was deduced for dealing with non-uniformly sampled signals,and was applied to analyze the spectrum of beat signal in Doppler laser radar.Finally,target range was obtained by calculating correlation function of laser echoes and the local modulating codes.Meanwhile,target speed was obtained by analyzing the spectrum of beat signal between laser echoes and local reference signal.By the proposed method,stable and reliable measurement of range and speed can be achieved,with range and speed errors are in the level of cm and cm/s,respectively,and the length of transmission signal meets the requirement of complex environment sensing for intelligent driving vehicles.The expected results have potential applications on fabrication cost of vehicle laser radar is expected to be reduced,and target sensing performance is improved.