The description of space VLBI Geodesy Demonstration Experiment (GEDEX) is presented, and the singularity problem arisen from geodetic space VLBI observations of a single radio source is discussed.

• 介绍了测地空间VLBI论证实验(GEDEX)的观测方案、预期目标和已获得的实测资料概况， 并对测地空间VLBI单源观测导致的奇异性进行了理论分析和数值检验。