基于火星巡视器车载激光诱导击穿光谱仪系统设计米散射激光雷达可行性研究

摘要

火星大气气溶胶的地基探测对研究火星大气环境具有重要意义,为了能够在节约火星巡视器/着陆器体积、重量的条件下进行气溶胶探测,论证了基于巡视器车载激光诱导击穿光谱仪系统设计米散射激光雷达方案的可行性.所设计的米散射激光雷达系统使用巡视器车载激光诱导击穿光谱仪的既有硬件资源,加入分光元件和探测器模块,构成与激光诱导击穿光谱仪系统集成的米散射激光雷达,米散射激光雷达与激光诱导击穿光谱仪在火星地表分时工作,互不影响.为了论证所设计的米散射激光雷达的探测性能,对Phoenix火星探测任务中独立的米散射激光雷达得到的一组原始回波信号数据进行了处理,反演得到一组典型火星大气消光系数廓线,结合消光系数廓线与系统硬件参数计算了所设计的米散射激光雷达的回波信噪比,结果表明该系统在所用原始数据被记录的当日在火星大气边界层顶4 km高度处信噪比达到26 dB,在10 km高度附近下降到0 dB,说明基于火星巡视器车载激光诱导击穿光谱仪系统设计米散射激光雷达进行气溶胶探测具有现实可行性.对比Phoenix的独立米散射激光雷达设计方案,基于激光诱导击穿光谱仪的米散射激光雷达不但能够节省巡视器体积、重量,而且发射能量更高,回波接收方案更为简单,数据反演步骤更为简洁.%It has important significance on the investigation of ground-based detection of mars aerosol for study mars atmospheric environment.To perform aerosol detection based on the constraint of saving mars rover's or lander's volume and weight,we investigated the feasibility of designing a Mie-Lidar which compacted with rover based Laser Induced Breakdown Spectroscopy (LIBS).Beam splitter parts and detection module,along with rover based LIBS's hardware,comprised the LIBS based Mie-Lidar,the LIBS and the Mie-Lidar work independently and they didn't interfere each other.One day's primitive data collected by Phoenix mission's lander was processed,and extinction coefficient profile was derived,with this profile and LIBS's parame-ter,signal-to-noise ratio(SNR)of the Lidar calculated.The result showed that LIBS based Lidar reached SNR of 25 dB at 4 km height,i.e.,top of martian boundary layer,and downgraded to 0 dB around 10 km altitude.Such outcome proved that letting LIBS based Mie-Lidar working on mars is feasible.It is not only volume and wight saving,but simplifies data recovering proces-sess when we detect mars aerosol with LIBS based Mie-Lidar.