The Automatic Compensation Technology Of Ranging Error Caused By The Change Of Atmospheric Refractive Index

With the development of science and technology,the requirement of distance measurement accuracy is increasing.The performance of indicators of ranging system includes precision,real-time and measuring-range.These developments guide the direction of the rangefinder technology.The lasers has many advantages,such as good monochromaticity,high brightness and good coherence,the laser rangefinder has been developed.The laser rangefinders play an important role whether civil or military.According to different measurement principles,the laser range finder is divided into pulse type,phase type and interference type.The phase-type is the most widely used because that has the advantages of high precision and high measuring range.The performance of the phase detector of the phase detection laser ranging system is a major factor influencing the ranging accuracy.Trying to improve the phase accuracy is an important way to improve the measurement accuracy.Based on the previous research,this thesis put forward the method of accumulation is developed to detect weak signal.The simulation results show that this method can improve the accuracy of the phase detection,and the effect is significantly.In addition,the index change of the air is one factor to influence the accuracy of ranging.For this problem,we proposes a new refractive index compensation method that can effectively compensate the refractive index over the entire measurement path.The research shows that the compensation method can achieve ideal results,and the accuracy of the refractive index compensation depends on the accuracy of phase discrimination.The main contents of this paper include the following aspects.Fist,the development history and application background of laser range finder and refractive index measurement are introduced.Several common distance measurement methods and refractive index calculation methods are briefly analyzed.Secondly,the principle of the phase method ranging is described in detail,and the choice of the scale is analyzed.Thirdly,several commonly used methods of phase detection are introduced,and the digital phase detector method is selected by comparison.Fourthly,the principle of correlation detection is theoretically deduced.The principle of zero-phase phase discrimination and “ swing method” phase discrimination is introduced.Based on the zero-crossing method phase discrimination,refractive index compensation and accumulation detection are introduced,and the detailed theoretical formulate of the two methods are deduced respectively.Finally,we design a reasonable simulation model for the method,and proved the effectiveness of our method by data analysis and calculation.