Study On Fiber Dispersion And Tuning Bandwidth Of Frequency Modulated Continuous Wave Laser Ranging

The measuring technique of precise spherical coordinate for large space is widely used in on-site processing and assembly of key equipment.Laser measurement,a significant method for space coordinate measurement,has become an important means to develop the space measurement of non-cooperative target.As a technology of non-contact absolute distance measurement,frequency modulated continuous wave laser ranging technology has the advantage of non-cooperative target ranging,high precision and high resolution,and has attracted extensive attention.The high-precision ranging within a hundred meters by frequency-modulated continuous-wave laser ranging technology has become a research hotspot,and the main research of this technology is about how to improve the precision and resolution of high-precision ranging.The main content of this dissertation is as follows:1.This dissertation studied the basic principle of frequency-modulated continuous-wave laser ranging,analyzed the main factors affecting the precision and resolution of ranging,put forward solutions for different factors,and set up an experimental device for frequency-modulated continuous wave laser ranging with double-optical path,as well as verified the feasibility of correcting the nonlinearity of frequency modulation by equispaced-phase resampling of optical frequency2.This dissertation studied the principle of the effect of optical fiber dispersion on the precision of frequency modulated continuous-wave laser ranging,improved the experimental device for frequency-modulated continuous-wave laser ranging within a large length,and put forward a frequency-regulation-based phase compensation for correcting optical fiber dispersion.The experimental results showed that the after the optical fiber dispersion is corrected,the maximum ranging error in the 65 m was less than 500 ?m,while the standard deviation was 246 ?m,and the precision of the ranging was significantly improved than that of the ranging before the correction of optical fiber dispersion.3.This dissertation studied on how to improve the bandwidth of frequency modulation by signal splicing,used the sinusoidal frequency modulation instead of linear frequency modulation to improve the measurement speed,and put forward that the signal splicing error could be eliminated by normalized quadrature modulation.The experiment showed that the measuring speed of sinusoidal frequency modulation increased about 10 times,and the equivalent bandwidth after the signal splicing by normalized quadrature modulation was 1.2 THz,while the resolution for frequency spectrum reached 127 ?m,which was close to the theoretical resolution.