Research On Ranging Measurement Algorithm Based On Frequency Modulated Continuous Wave Laser Radar And Its Spherical Coordinate Measurement

As a laser ranging measurement method,Frequency Modulated Continuous Wave(FMCW)laser ranging is a stable beat frequency signal which is formed by the frequency linear modulated transmitting signal and echo signal,and then the distance information of the target is extracted by the fast Fourier transform.Compared with other laser ranging methods,the method has the characteristics of high ranging accuracy and resolution,wide ranging range and it is suitable for non-contact measurement without cooperative targets,so it is widely used in the 10-100 meter large-scale measurement range.At present,how to improve the ranging accuracy and resolution of the ranging system is one of the important research directions in the field of laser ranging.The main works of this paper are as follows:1.The equispaced-phase resampling algorithm was deeply researched and then a new resampling method is proposed.That is,taking out the peak-valley position and the zero position of the beat signal at the same time and then resampling at the above position,the sampling frequency of the auxiliary signal can be doubled compared with the previous sampling method.This method has doubled the range of system ranging and reduces the fiber dispersion caused by the length of auxiliary fiber when the distance to be measured is constant.2.A phase difference frequency estimation algorithm based on equispaced-phase resampling nonlinearity correction is proposed.This method is equivalent to a further refinement of Fourier spectrum,which can further obtain the information between two points in the Fourier spectrum and improve the ranging accuracy.The algorithm simulation and experiment are also carried out to verify the method.3.The principle of dual interferometer FMCW laser ranging system is analyzed and a new idea is proposed.A spectroscope and a 1/4 wave plate are introduced to form a new measurement optical path on the basis of the original dual-path interferometry system,and the optical path is doubled when the position of the target to be measured is unchanged,and the modification is proved by derivation.The new optical path can double the range resolution.4.The three-dimensional spherical coordinate measurement is realized aftermastering the dual interferometer FMCW laser ranging system,signal processing system and two-dimensional turntable operating system.