Ground-Based Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) Cumulative Station Position Product from NASA CDDIS

Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) Cumulative Station Position Product from the NASA Crustal Dynamics Data Information System (CDDIS). DORIS is a dual-frequency Doppler system consisting of a receiver flying aboard a satellite and a globally distributed network of ground beacons. The DORIS receiver on-board the orbiting satellite tracks the dual-frequency radio signals transmitted by the network of ground beacons and generates the DORIS data. A measurement is made of either the Doppler shift or absolute phase as the satellite’s orbit moves over the ground-based beacon. DORIS data records contain a time-tagged range-rate measurement with associated ancillary information. DORIS observations from a global network can be utilized for a variety of products. Analysis Centers (ACs) of the International DORIS Service (IDS) retrieve DORIS data on a regular basis to compute station position solutions for the DORIS beacons supporting the IDS network. The IDS Analysis Center Coordinator combines these individual AC solutions to generate a long-term DORIS position and velocity cumulative solution through a piecewise linear (position+velocity) model to describe the station motions. The cumulative position and velocity solution is obtained from the stacking of the weekly solution files and is then aligned to the current ITRF. The residuals of this stacking are of particular interest since they depict non-linear station motions.

Doppler轨道学及卫星无线电定位集成系统（DORIS）累积地面站位置产品，源自美国国家航空航天局地壳动力学数据信息系统（CDDIS）。DORIS为一套双频Doppler系统，由搭载于卫星上的接收机和全球分布的地面信标网络组成。环绕卫星上的DORIS接收机追踪由地面信标网络发出的双频无线电信号，并生成DORIS数据。在卫星轨道跨越地面信标时，测量Doppler频移或绝对相位的偏移。DORIS数据记录包含带有时标的距离速率测量值及相关辅助信息。国际DORIS服务（IDS）的分析中心定期检索DORIS数据，以计算支持IDS网络的DORIS信标站的位置解。IDS分析中心协调员将这些单独的分析中心解合并，通过分段线性（位置+速度）模型生成长期DORIS位置和速度累积解，以描述站点运动。累积位置和速度解是通过堆叠每周解文件获得的，随后与当前国际地球自转参考框架（ITRF）对齐。该堆叠的残差特别引人关注，因为它们描绘了非线性的站点运动。