Research On Data Processing And Linear Frequency-modulated Signal Generation Technology In Laser Ranging System

With the rapid development of laser technology,laser ranging technology has been widely used in various fields.Laser ranging technology has the characteristics of large-scale,high-precision and so on.It is one of the most important techniques in high-precision distance measurement.This paper mainly studies two laser ranging technologies:laser ranging technology based on single photon detection and laser ranging technology based on linear frequency-modulated continuous wave.The first one is suitable for remote laser ranging and weak echo signals detection,the second one is suitable for large-scale spatial precision measurement with high precision and non-cooperative target matching.The two kinds of laser ranging technologies have great significance for aerospace and large-scale manufacturing.Based on the above viewpoints,this paper has carried out the works in the following two aspects:1.The research of laser ranging algorithm based on single photon detection and its experimental verification are carried out.This paper introduces the principle of laser ranging technology based on single photon detection,and carries out system algorithm design,algorithm simulation,and experimental results verification.2.In the aspect of laser ranging based on linear frequency-modulated signal,this paper proposes and experimentally validates a technical scheme based on optoelectronic oscillator to generate linear frequency-modulated signal,and carries out the analysis of current situation,theoretical simulation and experimental verification.In the aspect of laser ranging algorithm based on single photon detection,this paper proposes a scheme based on pseudo-random code,data superposition and correlation operation for laser ranging.By performming correlation operation with transmitting pseudo-random code sequence and receiving pseudo-random code sequence,the distance information can be measured,anti-noise performance of the system is improved by using the data superposition method.Finally,the system can measure the target in distance of 5 km,that is,the round trip distance is 10 km,and explore the influence of different superposition times on the detecting distance.Experiments show that the more superposition time is,the farther distance can be measured by the system.When the superposition time is 3000,the maximum critical attenuation can be measured is 113.77dB.In the aspect of linear frequency-modulated signal generation technology,this paper proposes a scheme based on optoelectronic oscillator combined with electrical frequency-selected cavity to generate linear frequency-modulated signal.By adjusting the bias voltage of phase shifter in the electrical frequency-selected cavity,and utilizing the frequency pulling effect between the output signal of optoelectronic oscillator and electrical frequency-selected cavity,linear frequency-modulated signal with a central frequency of 8.3 GHz can be produced.Its frequency range is about 550 MHz,the tuning rate is about 5.5 MHz/?s,and a time-bandwidth product is up to 5.5×10~4(bandwidth 550 MHz;temporal period 100?s).The system has the advantages of simple structure,high spectrum purity,low phase noise,and the phase noise is as low as-116 dBc/Hz@10 kHz.