Ⅰ. INTRODUCTION There are two worldwide permanent networks for determining pole motion using Doppler tracking data: the DMA and the MEDOC respectively under the charge of Defence Mapping Agency in USA and GRGS/CNES i...Ⅰ. INTRODUCTION There are two worldwide permanent networks for determining pole motion using Doppler tracking data: the DMA and the MEDOC respectively under the charge of Defence Mapping Agency in USA and GRGS/CNES in France. The precise ephemeris展开更多
文摘Ⅰ. INTRODUCTION There are two worldwide permanent networks for determining pole motion using Doppler tracking data: the DMA and the MEDOC respectively under the charge of Defence Mapping Agency in USA and GRGS/CNES in France. The precise ephemeris