LEO-LEO掩星探测频点选择分析与仿真研究

Analysis and simulation of frequency selection of LEO-LEO occultation atmosphere detection

LEO-LEO低轨掩星探测是高效的地球大气层探测技术,探测频率的选择是掩星探测计划的重要环节。首先,详细分析水的复介电常数与频率之间的关系,以及大气中水汽和氧气分子对电波的衰减情况,得出10~30 GHz适合作为LEO-LEO掩星的探测频段;其次,在可行探测频段范围内选择3个探测频点进行仿真研究,给出120次LEO-LEO掩星事件的温、压、湿廓线及对应的误差廓线图,并将仿真结果与标准大气模式对比:大气压力最大相对偏差为0.5%,温度最大标准偏差为0.8K,湿度最大标准偏差为0.47 g·kg^(-1),达到LEO-LEO掩星探测的精度要求;得出14.6GHz、17.4 GHz和22.6 GHz适合作为LEO-LEO掩星探测的频点,为LEO-LEO掩星探测频率的选择提供了参考。所得结论对进一步发展LEO-LEO掩星探测计划,提高大气探测精度具有重要的科学意义。

LEO-LEO radio occultation measurement is a high-efficiency detect technology. Frequen- cy selection is an important part of the occultation exploration program. Firstly, This paper analyses the dielectric constant of water in the atmosphere and atmosphere absorption and then draws the conclusion that 10-30GHz will be suitable as a LEO-LEO occultation detection band. Secondly, we select three fre- quencies and give one hundred and twenty LEO-LEO occultation events of temperature, pressure, humid- ity profiles and corresponding error profiles. Compared with standard atmosphere model, the maximum standard deviation of atmosphere pressure, temperature and humidity are 0.5%, 0. 8 K and 0.47 g. kg-~, respectively, which meet the accuracy of LEO-LEO occultation detection, then we draws the con- clusion that 14.6 GHz, 17.4 GHz and 22.6 GHz are the favorable frequencies for LEO-LEO occultation detection. The conclusions are important to further develop LEO-LEO occultation exploration plan and im- prove the atmosphere detection accuracy.