【作者】 张飞鹏；

【导师】 黄珹；

【作者基本信息】 中国科学院上海天文台 ， 天体测量与天体力学， 2000， 博士

【摘要】 PRARE（Precise Range And Range-rate Equipment）是二十世纪九十年代由德国发展的一种双频、双程、空基、微波卫星跟踪系统，可以为人造卫星提供精密的距离和距离变化率两种观测，单次观测精度分别为2.5-6.5cm和0.1mm/s，标准点精度为1cm和0.015mm/s. PRARE系统具有全天候、全自动、观测数据密集、地面站易于流动等优点．其空间部分自1995年4月起搭载在欧洲空间局的第二颗资源遥感卫星ERS-2上，并正常工作至今． 本文分析了PRARE提供的跟踪数据，并将其用于ERS-2卫星的精密定轨．主要内容如下： 1.介绍了PRARE系统的构成和工作、测量原理，给出了PRARE系统的观测模型，重点是基 于空间的双程距离变化率模型。 2.分析了ERS-2卫星的表面几何模型和姿态变换特征，给出了卫星在任意方向上横截面积的计 算方法。 3.介绍了用于ERS-2卫星精密定轨的各种力学模型。重点分析了表面力（包括大气阻力和升 力、太阳光压、地球反照辐射压）模型，并针对实际情况作了适当的改进。在摄动量级估计的 基础上，对各种摄动因素作了取舍。 4.分析了PRARE观测的改正值．重点分析了对流层折射改正，对目前宣称精度较高的几个映 射函数作了比较，结果表明，在观测高度角5°以上，各映射函数相差无几。 5.分析了海洋负荷引起的台站水平位移对定轨计算的影响，认为在目前的解算精度水平上，海 洋负荷引起的台站水平位移不能忽略． 6.完成了精密定轨软件SHORDE的移植、调试，并将软件中的常数系统和各种模型按照IERS1996 规范作了更新，使定轨精度有了大幅度提高．将处理PRARE资料的功能和ERS-2卫星的 各种模型加入 SHORDE中，建立了综合利用SLR和PRARE资料进行ERS-2卫星精密 定轨的软件。 7.编写了数据剪辑程序PASEDT和DATEDT，对PRARE资料作了细致的预处理． 8.将方差分量估计（VCE）方法结合 Givens-Gentleman正交变换算法应用到卫星精密定轨 计算中，基本解决了多种资料综合定轨时观测资料的合理加权问题。同时，在对Helmert方 差分量估计方法深入分析的基础上，提出利用待估参数的先验信息来消除VCE结果中可能 出现的负方差，效果显著．讨论了先验约束强弱的设置和非整数自由度的问题．在此基础上， 编写了适用于人造卫星精密定轨的方差分量估计程序VACE。 1＜n＞ 9．根据试验计算，拟定了详细的 ERS－2定轨计算方案，计算了 1997年 ERS－2卫星的轨道。经 过多方面的检验，估计轨道的径向精度为3—5厘米，完全可以满足利用测高资料对海洋表 面研究的需要，法向精度为10—20厘米，可以满足合成孔径雷达干涉测量的需要．更多还原

【Abstract】 PRARE (Precise Range And Range-rate Equipment) is a space-borne, two-way, two-frequency microwave satellite tracking system developed by Germany in 1990’s. PRARE canautomatically provide precise range and range-rate measurements under all weather condi-tions, with full-rate precision 2.5 - 6.5 cm for range and 0.1 mm/s for Doppler, normal-pointprecision 1 cm and 0.015 mm/s, respectively. Its space segment has been carried by the 2ndEuropean Remote Sensing satellite ERS-2 since April, 1995 and works normally up to now.This dissertation analyzed the tracking data provided by PRARE, and applied the datato precision orbit determination (POD) for ERS-2. In summary, the main contents are asfollow:1. Introducing the system composition and measurement principle of PRARE. Presentingmeasurement models for PRARE observations, especially the space-based two-way range-rate model.2. Analyzing the surface geometric model and attitude transformation characteristics ofERS-2. Presenting the computational formula of cross-sectional area in any direction forthe satellite.3. Introducing dynamic models used in ERS-2 POD, analyzing surface force models inemphasis, including atmospheric drag and lift, solar radiation pressure, Earth albedoand emissivity. Some proper modifications on the models were made. Based on themagnitude estimation of each perturbing factors, made a choice among the perturbationmodels.4. Analyzing the corrections of PRARE observations, and tropospheric delay corrections inemphasis. The comparisons among several mapping functions with high nominal preci-sion showed, that the mapping functions are all similar in accuracy above 5°elevation.5. Analyzing the effect of horizontal station displacement due to ocean loading on PODcWutation, conc1uded that the horizontal station disp1acement caused by ocean loadingshould not be neglected in current computational accuxacy.6. Updating the constants and models in the POD software SHORDE according to IERSConvention (1996). Adding PRARE and ERS-2 models into SHORDE, made the com-bination of SLR and PRARE data for ERS-2 POD possible.7. Editing the PRARE data carefully by using data-edit program PASEDT and DATEDT.8. App1ying the Relmert method of variance-comPonent-estimation to POD comPutationconsidering Givens-Gentleman orthogonal transfOrmation method simultaneous1y. Thismade the data-weighting moe prOPer in POD comPutation while combiaing severalkinds of observations. Moreover, based on the deep analysis of Helmert VCE method,we brought forward a the improved Helinert VCE method n which remove the possiblenegative variance esthaation by using the a priori infOrmation of solved-for parameters.The experAnenis showed that the twroved method was effective in avoiding the negativevariance. The probIems about the strength of a priori constraints and noninteger degreeof freedom were discussed.9. Detendning the scheme fOr ERS-2 POD computation according to experimental com-putations and comPuting ERS-2 orbits in 1997. According to the accuracy assessmentfrom several aspects, the accuracy estAnation of 3 -- 5 cm in radial direction and 10 -- 20cm in normal direction are given. This precision can comP1etely satisfy the requlrementof ocean surface research by using altAnetry, and basically satisfy the requlrement ofInSAR measuxement.更多还原