A Method of Calibrating the Gain Ratio of Polarized LiDAR

Abstract

The present invention discloses a method for calibrating the gain ratio of a polarization lidar. The method includes the following steps that: a half-wave plate is arranged in front of a polarization beam splitter prism in a polarization lidar receiving system; the fast axis of the half-wave plate can face any direction, light intensity IR and light intensity IT received by the reflection channel detector and transmission channel detector of the polarization beam splitter prism are recorded; the half-wave plate is rotated by 45 degrees, and light intensity IR and light intensity IT received by the reflection channel detector and transmission channel detector are recorded; and the light intensities received by the two detectors before and after the rotation of the half-wave plate are introduced into an equation that (IR+IR) / (IT+IT)=G, so that the gain ratio G of the polarization lidar can be obtained. The calibration method strictly agrees with Miller matrix-Stokes vector theory, and can directly obtain the gain ratio of the polarization lidar system. The calibration method has good robustness. The calibration result of the calibration method is not affected by factors such as the non-ideal linear polarization of emission laser, atmospheric conditions, and the non-ideal polarization characteristic of an optical element in front of the half-wave plate. The calibration method is high in accuracy and extremely simple to operate.

Description

technical field [0001] The invention relates to calibration of polarization laser radar, in particular to a method for calibrating the gain ratio of polarization laser radar. Background technique [0002] When light interacts with particles and scatters, according to the shape and size of the scattered particles (relative to the emitted laser wavelength), the polarization state of the backscattered light will change to varying degrees. It is against this background that polarization lidar was developed. of. Polarization lidar is an active remote sensing technology, which is an important part of atmospheric and ocean detection. Polarization lidar can distinguish spherical particles and non-spherical particles in the measured area, significantly improve the inversion accuracy of particle microphysical properties, and can also be used to study multiple scattering. The basic principle of polarization laser radar is to emit a beam of high-purity linearly polarized light, and ad...

AI Technical Summary

Problems solved by technology

However, in the Mueller matrix-Stokes vector theory, this method cannot obtain the real system gain ratio, and the calibration result will be affected by the optical elements before the polarization beam splitter prism in the receiving system

In addition, when using this calibration method, it is necessary to first adjust the orientation of the fast axis of the half-wave plate so that the polarization plane of the incident light is aligned with the incident plane of the polarization beam splitter prism. However, this alignment process will bring a non-negligible calibration error

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