Precision Analysis Of Rapid Ranging System Based On Dual Femtosecond Lasers

Distance measurement has been playing a very important role in social life of human beings.With the development of science and technology,distance measurement presents some new trends,e.g.larger scale and higher accuracy.In recent years,femtosecond laser has been applied to distance measurement as light source,and it shows some outstanding features.This paper introduces a rapid ranging system using two femtosecond lasers by means of equivalent sampling and makes a detailed analysis focused on the factors affecting the precision of the distance measurement system.The main contents of this paper are as follows:1.Review the history and current situation of distance measurement and laser,compare and summarize the advantages and disadvantages of the traditional distance measurement methods and present the latest progress in the field of laser measurement at home and abroad;2.Review and study relevant theoretical knowledge,such as the principle of femtosecond laser,the principle of equivalent sampling and the concept of timing jitter.3.Build several fiber laser sources for absolute distance measurement and measure the necessary parameters,set up the optical path to realize the optical equivalent sampling.4.Build up simulation model for distance measurement based on two femtosecond lasers and write program to analyze the impacts of laser timing jitter,laser frequency stability,data acquisition and the influence of temperature in this rapid ranging system.5.Put forward the final ranging accuracy improvement opinions according to the properties of the various factors affecting the results,including the design of the laser,the designation of the distance and selection of the data acquisition equipment.Finally,the precision of the ranging system that we built achieves 3 micrometers at 1.5 m and the update rate reaches 2000 Hz.By average of 20 times,the precision can be promoted to about 100 nm and the corresponding update rate is 100 Hz.The ranging accuracy can be promoted to a higher level on the basis of the analysis of above factors by selecting the appropriate lasers,measured distance and data acquisition equipment,which will provide effective solution for large scale and high precision distance measurement application.