Simulation Analysis And Experimental Research On Detection Technology Using Linear Frequency Modulated Coherent Laser

With the development of the society,small aircraft in the field of military and civilian plays a more and more important role,if they could be developed the miniaturization,remote detection,high resolution laser radar will further promote the development of small aircraft.In this paper,my research programme is taking linear frequency modulation(LFM)of intensity for long pulse laser and the receiver uses the method of coherent detection,after the acquisition of signal,method pulse compression processing is used.The programme has been verified for increasing detection range and improving ange resolution at the same time from two aspects of simulation analysis and experimental verification.First,it analyses the frequency spectrum of linear frequency modulation signal and the relation of modulation bandwidth and width of pulse compression,and noise immunity of matched filtering,based on the analysis of domestic and foreign scientific research institutions in the coherent laser radar and laser radar waveform modulation.It discusses extraction of distance and distance measurement error of matched filtering.Ac-cording to the basic theory of coherent detection,laser signal of linear frequency modulation amplitude coherent detection has carried on the theoretical derivation.Secondly,in order to solve the problem that using pulse compression of matched filtering can cause strongly targeted sidelobe covered nearby weak target at the case of multiple target detection,it discusses main-to-side lobe ratio and pulse compression width of detecting target at the case of different compression ratio using 7 window functions.For different intensity of multi-objective,it respectively uses matched filtering add window,LS pulse compression and RMMSE adaptive pulse compression,analyzed the advantages and disadvantages of these four methods from different angles.Finally,to verify the feasibility of inear frequency modulation of coherent laser detection technology,the experimental set of it is built up.The experimental results show that about emission signal,bandwidth of it is 5 MHz and pulse width is 500 ?s,returned signal's main-to-side lobe ratio is 12.71 dB,pulse width is 183.2 ns,pulse compression ratio is 2729 after coherent detection and matched filtering.It proves that linear frequency modulation of coherent laser detection technology can improve the range resolution.