摘要
相较于传统的两步法,动力学一步法能充分利用观测数据的原始信息,理论上可获得更合理的时变重力场产品,同时也因其涉及的参数维度更多样、函数模型更复杂,一直是当前研究的热点和难点.本文研究并实现了动力学一步法恢复时变重力场,给出了合理的数据处理策略,而后基于GRACE-FO(GRACE Follow-On)星载GPS数据和KBR(K/Ka Band Ranging)距离变率数据反演了2021—2022年60阶全球月时变重力场模型.对于一步法中诸多技术细节,本文重点分析了先验权和经验参数对轨道确定和模型反演的影响,研究表明:当采用30 s采样率的GPS数据时,需适当对GPS数据降权,以免引入过多噪声,码伪距、载波相位和KBR距离变率数据的先验权比应为1:104:1014;为了保证轨道和模型质量,在反演过程中有必要引入经验参数以吸收残余的摄动力误差,相较其他经验参数(分段周期经验加速度、几何经验参数),分段常经验加速度在保证定轨精度的同时可更有效地吸收模型中的噪声.此外,在采用相同动力学参数配置时,动力学一步法反演的时变重力场模型无论是与官方模型的一致性还是内符合精度均优于两步法.最后,综合评估了整个时间跨度的轨道和时变重力场模型质量,结果显示,动力学一步法确定的轨道可满足厘米级需求,双星的卫星激光测距残差标准差均为1.6 cm,重力场模型与官方机构CSR(Center for Space Research)、JPL(Jet Propulsion Laboratory)、GFZ(GeoForschungsZentrum Potsdam)最新发布的RL06.1模型一致性较好,在保留完整时变信号特征的前提下,噪声表现与CSR模型相当,优于JPL、GFZ模型.
Compared to the traditional two-step method,the dynamic one-step method fully utilizes the raw information from the observation data and theoretically yields more accurate time-variable gravity field products.However,due to the problems with the complexity of parameter space and functional model,one-step method remains a key focus and challenge in current research.We study the dynamic one-step method,presents a reasonable data processing strategy,and obtain the 60-degree temporal gravity fields for the years 2021—2022 from GRACE Follow-On(GRACE-FO)GPS and K/Ka Band Ranging(KBR)rang rate data.For the technical details of the one-step method,we focus on analyzing the impact of a priori weighting and empirical parameters on orbit and gravity field determination.The study reveals that when using GPS data with a 30 s sampling,it is necessary to downweight the GPS data appropriately to avoid introducing excessive noise.The recommended a priori weight ratio for code,carrier phase,and rang rate data is 1:104:1014.To ensure the quality of the orbit and the gravity field model,empirical parameters are suggested to be co-estimated with other parameters to absorb residual perturbative force errors.Among various empirical parameters(such as piecewise periodic accelerations and kinematic empirical parameters),piecewise constant accelerations are more effective in absorbing noise in the model while maintaining orbit accuracy.Furthermore,under the same dynamic parameter configuration,the time-variable gravity field model driven from the dynamic one-step method outperforms the two-step method in terms of both consistency with the official model and precision.Finally,a comprehensive evaluation of the orbit and time-variable gravity field model over the entire time span is conducted.The results indicate that the orbits determined by the dynamic one-step method meet centimeter-level requirements,with a standard deviation of 1.6 cm for the satellite laser ranging(SLR)residuals of twin satellites.The gravity field model exhibits good consistency with the latest RL06.1 models released by CSR(Center for Space Research),JPL(Jet Propulsion Laboratory),and GFZ(GeoForschungsZentrum Potsdam).While preserving the full characteristics of time-variable signals,the noise performance is comparable to the CSR model and better than the JPL and GFZ models.
作者
张佳辉
游为
万祥禹
余彪
范东明
ZHANG JiaHui;YOU Wei;WAN XiangYu;YU Biao;FAN DongMing(Faculty of Geosciences and Engineering,Southwest Jiaotong University,Chengdu 610097,China)
出处
《地球物理学报》
北大核心
2025年第9期3338-3352,共15页
Chinese Journal of Geophysics
基金
国家自然科学基金项目(42474005,42174014)资助.
作者简介
第一作者:张佳辉,男,1996年生,博士生,主要研究方向为卫星精密定轨和时变重力场反演.E-mail:zhangjiahui1996@foxmail.com;通讯作者:游为,男,副教授,主要从事大地测量学、地球重力学的研究.E-mail:youwei@swjtu.edu.cn。
