The Geostationary Synthetic Thinned Array Radiometer represents a promising new approach to microwave atmospheric sounding from geostationary orbit based on passive interferometry. Distortion due to mechanical or thermal constraints produces a displacement of the ideal antenna positions in the array that causes sampling errors. In this paper, the impact of array distortion on radiometric error is analyzed in detail so as to identify the dominant sources of error. A preliminary analysis showing that array distortion can be well corrected by means of an external phase reference is also presented.