| In recent years, with the development of the laser technology, Rayleigh-Brillouin lidar remote sensing in the temperature and environment monitoring of seawater and atmosphere is getting more and more attention and research. The demand of high precision of detection results is rising along with continuous study of Rayleigh-Brillouin lidar detecting technology at home and abroad. And the impact of the system noise has gradually received attention, so research on noise influence on measurement of Rayleigh-Brillouin lidar with high accuracy is of great significance for the actual measurement applications.The noise characteristics of ocean and gas Rayleigh-Brillouin lidar system, based on F-P etalon combined with ICCD and F-P interferometer respectively are studied in this paper,. It shows that the influence of random noise is a key factor affecting the accuracy of measurement results. And analysis the influence of the random noise with simulation spectrum of seawater and spectrums of the S6 as well as V3 model of atmosphere under different SNR, and the experimental verification of the aspects in the seawater is discussed. The results indicate that in the aspect of seawater, when SNR is greater than 16 dB, the uncertainties and averaged errors of Brillouin frequency shift and linewidth are in MHz magnitude, while those of temperature are both in 0.2 oC. With the method of averaging multiple measurements in practical application, the requirement of SNR will reduce to 9 dB for the temperature measurement accuracy of 0.2 oC after the five-time averaging. In the aspect of gas, it shows that with the temperature, pressure, bulk viscosity and Brillouin frequency of V3 model reach 0.2 oC, 0.02 bar, 0.2×10-5 kgm-1s-1and 0.2 MHz separately, the corresponding SNR requirements should over 29 dB, 16 dB, 24 dB and 26 dB.. This simulation and analysis of noise provide a reference and guide for the future research of the ocean and atmosphere Brillouin lidar in high precision applications. |
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