The Performance Detecting And PC Software Development Of High-precision Polarimeter

Polarization information has a unique advantage in the process of aerosol retrieval, but the precondition is that it must have a very high polarization detection accuracy. Therefore, how to obtain more accurate polarization Strokes vector parameters is the most important problem in the field of polarization remote sensing. Recently, Anhui Institute of Optics and Fine Mechanics of Chinese Academy of Sciences developed a high-precision polarimeter which is designed by time-shared polarization measurement with a common polarization measurement path. The polarimeter has seven spectra channels and its detecting bands range from 490nm to 2250nm. As a polarization remote sensor, the high-precision polarimeter can not only get polarization information of the scattering light of sky, but also acquire the solar radiation intensity at the same time. Different from the traditional polarization measurement method of three detection polarization angles, the high-precision polarimeter doesn’t have error brought by separated aperture design of the instrument. So it doesn’t need to do tedious polarization calibration experiments to ensure the instrument’s measurement accuracy. Also, due to the instrument has more than thirty polarization detecting direction, the random noise is repressed effectively. Therefore, the high-precision polarimeter has opened up a new design concept of the polarization remote sensor.The main research goals of this paper are detecting the high-precision polarimeter’s performance and developing its PC control software to help those performance detecting experiments carried out automatically. The performance detecting area includes instrument’s basic properties like dark current, field consistency, linearity and the polarization measurement accuracy of the instrument. The PC control software is designed according to the experiments’ demand which has greatly improved work efficiency.In this paper, the basic performance of the polarimeter is analyzed, the assembling method for off-axis parabolic mirror based on ellipse detection and the large dynamic range linear detection method using the sun as reference light source are proposed. Also, under the condition of two kinds of polarized light, namely non polarizing light and full polarizing light, the measurement accuracy of the polarimeter is verified. The paper work also includes the instrument’s radiometric calibration test using Langley method in Hefei, which provided a reference for its future field radiometric calibration work. At last of this paper, the development of PC control software is introduced in detail.The performance test results show that the basic performance of the radiometer is fine, and the accuracy of the polarization detection is higher than most of polarimeters. Besides, the PC control software realized a set of functions such as preprocessing algorithm, solar tracking, database storage and instrument control. Moreover, the software’s perfect performance and friendly interface can also meet the various requirements of the tests well.