Influence of modulation function on precision of laser ranging based on polarization modulation

In order to reduce the ranging error caused by the pulse timing or phase comparison of the complex circuit system in the traditional laser ranging method, the laser ranging based on polarization modulation was demonstrated. Using the characteristic that the crystal refractive index of the electro-optical modulator changed with the linear change of the applied electric field, the laser pulse reflected by the object to be measured was made into a function of time, and the distance was solved by the ratio of the light intensity in the two vertical directions. Based on the principle of distance measurement, distance equation and error analysis, the accuracy expression of theory ranging that was obtained by the ranging method in the paper, the influence of three kinds of modulation functions of sine, sawtooth and exponential on the accuracy of ranging was analyzed by simulation. In the same distance range, the sawtooth function had better applicability, and the combination of sine and exponential had higher accuracy of ranging. By analyzing the influence of different modulation bands of sine function on the accuracy of ranging, the applicability and the accuracy were greatly improved by using -/6-/6 band. The results will be helpful to improve the accuracy of laser ranging based on polarization modulation.