The conditions required to construct, a quasi-inertial celestial reference frame are discussed, and several cases, in which if the ground-based observation can satisfy, arc enumerated.

本文叙述了建立准惯性天球参考架应满足的条件，列举了几种地面观测能否满足这些条件的情况。

The summit brought together representatives of civil aviation authorities, ground-based and in-situ observation experts, modellers and satellite remote-sensing experts.

此次峰会汇集了民用航空权利机构的代表，地面和现场观测的专家，建模和卫星遥感专家。

A good forecast result has been concluded with a topological prediction model of gray system theory based on the observation data of ground water table in Lanxi County.

地下水枯水期水位预报对春季农业生产具有重要意义，利用兰西县地下水水位观测资料，应用灰色系统理论的拓扑预测建立模型进行预测，取得了较好的结。

Space weather is a new inter-discipline which combines space science, space borne and ground based observation technologies.

空间天气是一门把空间科学与天基、地基技术系统紧密结合，多学科交叉的新兴学科。