国际地球参考框架ITRF2020简介与评析

Introduction and Review of the International Terrestrial Reference Frame ITRF2020

国际地球自转与参考系统服务组织于2022年4月发布了最新的国际地球参考框架ITRF2020(the International Terrestrial Reference Frame 2020)。由于采用了更长的时间序列、更加完善的处理模型和更加优化的处理策略,ITRF2020的精度要优于ITRF2014。相对于ITRF2014,ITRF2020在原点和尺度参数实现策略上有显著改进,并第一次明确给出了季节性信号的原点、尺度和定向,即:(1)采用分段对准策略改进了原点和尺度参数实现方法;(2)分别给出了在地球质量中心和地球形状中心框架下的季节性信号的原点、尺度和定向实现,以及地球质量中心和地球形状中心框架下的谐波参数模型。此外,参与ITRF2020构建的各独立技术的数据处理也有显著进步。首先详细介绍了ITRF2020的4种空间大地测量技术数据处理进展以及技术间组合的技术进步,然后对ITRF2020基准实现进行简要分析,最后对其存在的不足进行初步分析与讨论。

The International Earth Rotation and Reference Systems Service(IERS)released the updated International Terrestrial Reference Frame ITRF2020 in April 2022(the International Terrestrial Reference Frame 2020).The accuracy of ITRF2020 is better than that of ITRF2014 because of the adoption of a longer time series,better processing models,and more optimized processing strategies.Compared with ITRF2014,ITRF2020 has significant improvements in the strategies for implementation of origin and scale parameters,and for the first time it explicitly provides the origin,scale,and orientation of seasonal signals;that is,①the strategy of segmented alignment is adopted to improve the origin and scale parameter realization;②the origin,scale,and orientation realizations of seasonal signals in the Center of Mass(CM)and Center of Figure(CF)frames,as well as the harmonic parameter models in the CM and CF frames,are given.In addition,there have been significant technological advances in data processing for each of the independent techniques involved in the construction of ITRF2020.In this paper,we first introduce in detail the progress of data processing within the four space geodetic technologies and the technical progress of the inter-technology combinations,then briefly analyze the ITRF2020 implementation,and finally provide a preliminary analysis and discussion of its shortcomings.