Research On Calibration Of Nonlinearity And Range Experiment Of Frequency Modulated Continuous Wave Lidar

In recent years, laser radar has been widely studied, especially the study infrequency modulated continuous wave (FMCW) lidar particularly in terms of precisionranging in depth. Laser radar system that combines the features of a series rangingsystem with high precision ranging, high ranging speed and adapt to complexenvironments and so on. Studied in this paper is based on the content of the basicprinciples of FMCW lidar system, designed to meet within a close distance precisionlaser radar systems, and one of the key technologies nonlinear frequency modulatedcorrection were studied, and ultimately verified the system ranging feasibility byexperiments.Firstly, give the basic principle of FMCW laser radar, and establish relationshipbetween the distance and the frequency of the beat signals, and according to the existingbasic theory of critical system components were selected. Secondly illustrate the effectof the laser frequency modulation nonlinearity in ranging experiments, results are givento illustrate. To eliminate this effect, give the introduction of synchronous samplingmethod for correcting nonlinear in frequency modulation, the theoretical model is givenand use the experiments to verify the result of this correct method. As correcting thenonlinear, we need to know the exact value about the arm length difference of thecorrection M-Z interferometer. So in this article, we use HCN gas cell to achieve it.Given the optical design about using HCN gas cell calibration arm length difference andgive a highly accurate calibration results by experiments. Finally, the experimentalsystem was designed and built it in this article finally adopted. Based on the system webuilt, the distance measurement experiments in both fiber and out space are done.Andby repeating the experiments, we verified the accuracy of the results, given the presenceof the error.