准确可靠地监测大气中CO2含量变化对于研究全球变暖和气候变化具有十分重要的意义。利用拉曼激光雷达测量大气中的CO2含量分布是一种新颖且容易实现的方法。有效地采集CO2气体的拉曼回波信号并进行数据处理反演出测量结果是整个系统的关键所在。根据拉曼激光雷达的原理和信号处理的理论基础,设计了单通道和双通道两种行之有效的拉曼信号采集方案,并分别对其信号处理方法进行了论证。阐述了单通道采集过程中能量波动所造成的对信号的影响和消除方法,重点解决了采集过程中存在的噪声干扰问题。计算了两种方案在采集1 km处的系统信噪比(SNR),单通道采集时约可达到10,而双通道采集时可提高到20左右。

Detecting the atmospheric CO2 reliably is becoming more and more important due to environment problems and climate changing. Raman light detection and range (lidar) system monitoring the atmosphere is a novel technique. It is a key factor to acquire the back signals of Raman lidar efficiently. The paper not only analyzes the principle of Raman lidar and the theoretical basis of signal processing, but also designs two schemes for collecting Raman signals, which include single channel and double channels, and demonstrates the methods of signal processing separately. The paper resolves the noise interference in collecting signals process, and gets the satisfied conclusion by contrasting the two results of the two schemes. Moreover, the signal-to-noise ratio (SNR) is calculated for the lidar system. The calculated results indicate that the SNR (for 1 km) is up to 10 for single channel, however, up to about 20 for double channels.