Research On Integrated Technology Of Vehicle Single-line Lidar And Communication

Aiming at the high mortality rate of traffic accidents in the world today,the Intelligent Driving Assistance System(ADAS)is considered to be one of the most promising solutions,and laser radar,which is the core sensor component of ADAS,is indispensable.In addition,vehicle-to-vehicle(V2V)communication technology plays an important role in improving vehicle safety,reducing environmental pollution and saving energy by transmitting information between vehicles.Take all these factors into account,takes MEMS solid-state lidar as the prototype,the lidar system integrates ranging and communication within only one set of hardware devices is studied in this thesis,and achieve multi-line effect through single-line scanning.The principle and characteristics of laser radar and free-space optical communication system are compared and analyzed,then integrated signal of time division multiplexing system based on optical orthogonal code and integrated signal of simultaneous system based on optical OFDM are designed.Firstly,the feasibility of the two signals becoming integrated signals is analyzed,and the communication performance and ranging performance of the signals are initially simulated and verified.Secondly,a step-scan signal processing algorithm is proposed to improve the precision and resolution of the echo signals processing of optical OFDM integrated signal,the accuracy and resolution of ranging and speed measurement are significantly improved.Finally,detailed system parameters are analyzed and designed in terms of practical application,and simulation results shows excellent performance of the proposed two integrated signals.The main work of the thesis is as follows:(1)1550nm is determined as the system operating wavelength through simulation analysis in views of different wavelength attenuation characteristics and human eye safety.The differences and similarities between FSO and Lidar system are compared and analyzed.Based on this,the design principles of integrated signals are proposed.(2)Integrated signal of time division multiplexing system based on optical orthogonal code is designed.PPM is selected as the single-carrier communication modulation mode through simulation comparison,based on this,the PPM-OOC time-division multiplexing integrated waveform is designed by using the pulse coding method,and its communication performance and ranging performance are initially analyzed,which overcomes the shortcomings such as low communication rate and complex data demodulation method in the existing integrated technology.Finally,integrated signal of wavelength division multiplexing system based on optical orthogonal codes is proposed.(3)Optical OFDM modulation is proposed to design the integrated waveform of the simultaneous system.Firstly,the variation of the optical OFDM symbol during the ranging process are analyzed and the single-symbol periodic optical OFDM ambiguity function is deduced,then the feasibility of the optical OFDM signal as the laser detection signal is verified.Further,the effects of data correlation,number of carriers and cyclic prefix on ranging performance are studied with ambiguity function tools.Finally,the ranging performance and communication performance of BPSK,16 QAM and P4 encoding data symbol mapping are compared and analyzed.(4)The parameters of the system are analyzed and designed in detail from the perspective of practical application.Based on this,the performance of the proposed two integrated signals is analyzed.Especially the integrated signal based on optical OFDM,in order to cope with the shortcomings of the resolution of signal processing algorithm based on modulation symbols,a high resolution signal processing algorithm based on stepping is proposed.The simulation results show that the integrated signal designed in this paper meets the practical application requirements.Compared with the original algorithm,the proposed high-resolution signal processing algorithm for optical OFDM integrated signals has significantly improved ranging/speed measurement accuracy and resolution.Finally,the two integrated signals designed in this paper and the existing integrated signals are compared and analyzed to analyze their advantages and disadvantages.