Laser Distance Measurement Based On The Shifting Phase Of Reflected Light

With the development of science and technology,laser has become increasingly important and widely applied because it has strong directivity,high luminance,good monochromaticity and superior coherence as well.As the production of laser technology,various kinds of laser application technology also arises at the historic moment,typical applications of laser ranging technology.The technology Laser has many unsubstitutable advantages,such as a large measurement range,high accuracy and excellent resolution,strong anti-jamming capability,light weight,small volume,etc.Therefore it has been widely used in industry,military,aerospace enterprise,the earth atmosphere detection and so on.In recent years,the domestic and foreign military institutions,scientific research institutions and companies have rushed to its experiment study and obtained wonderful results.Meanwhile with the rapid development of electronic technology and computer technology,the device of laser measurement tend to be also in the miniaturization of digitization,automation,low cost and light direction.Firstly,we will analyze the principle of the laser measurement;and in the based of the principle we can classify evidently the technology into four categories:Phase,Interferometry,Trigonometry and Pulse methods.In the thesis,we design the experiment scheme about the laser measurement length and make the corresponding experiment research.At the same time,in order to satisfy the experimental requirements better,we designed a photoelectric detector based on avalanche photodiode(APD),which has more advantages in the cut-off frequency and responding time in comparison with the PIN photodiode detector of THORLABS Company in some properties.It is showed that the APD could result in 10 nanoseconds delay of signal of in the frequency of 1 MHz-1 GHz.Secondly,in order to detect the phase difference between the reference and reflected light perfectly,phase locking technique is introduced in the subject.We can record out the value of the phase difference exactly and make the comparison of it and the theoretical calculation.Finally,the whole subject experimental results are analyzed,summarized and prospected in the end of the thesis.