上海天文台GPS掩星技术研究现状

PRESENT STATUS OF GPS/LEO OCCULTATION RESEARCH IN SHAO

简要地介绍了GPS/LEO卫星无线电掩星技术的基本原理、意义以及国际上的最近动态 ,列举了几个主要的LEO卫星计划 ;重点分析了GPS掩星探测地球大气技术中需要注意的若干问题 ,并推出可能采取的改进方案和相应的技术路线。上海天文台在GPS/LEO空基气象学中已经成功地提出 :通过通约LEO/GPS轨道方法 ,实现掩星地面观测点控制的新思路。作为一个应用实例 ,针对东中国海洋上空大气状况对中国东部经济发达的地区特别是上海地区的天气有着重要影响的背景 ,提出利用通约LEO/GPS卫星可对该地区大气实施监控。为了充分利用GPS/LEO掩星观测资源 ,上海天文台开展了振幅反演的计算方法研究 ;提出了在振幅反演中存在着无线电信号几何衰减和物理衰减两种不同的衰减机制 ,并考虑了它们的数学模型以及对反演结果的影响。简要地叙述了掩星质量因子的定义和计算方法。作为国内天文地球动力学研究中心 ,上海天文台将与国内外一些合作单位考虑建立GPS/LEO掩星技术观测处理的软件系统。作为空基GPS气象学的推广 ,还考虑进行山基和飞机载掩星观测实验 。

The recent progresses of GPS/LEO occultation technique and the occurred LEO missions were briefly reviewed in the beginning of this paper. Some scientific hot points of GPS occultation technique in SHAO, including pre-process of occultation observational data, commensurate orbit GPS/LEO satellites, amplitude retrieval, simulate computation model, assimilation of occultation data, high order correction in low atmosphere and the qualitative factor of occultation events, were very generally discussed. The new GPS/LEO occultation research projects and scientific cooperation plan in Shanghai Center for Astro-geodynamics Research, Shanghai Astronomical Observatory (SCAR/SHAO) were presented. A synthetic multi-function software package of GPS/LEO occultation technique was in the scientific developing schedule of SCAR/SHAO.