This paper presents an initial analysis of the possibilities for velocity and acceleration measurement with the Bi-Directional (BiDi) SAR imaging mode. The analysis comprises single satellite single path acquisitions as well as one path of a constellation of two satellites. The translational velocity components into azimuth and range directions are simulated for TerraSAR-X parameters. Image examples show velocity and acceleration effects on ships in the Singapore harbor area acquired with the TerraSAR-X (TSX) and TanDEM-X (TDX) satellites. Special attention is given to interferometric fringes observed on anchoring ships after the subtraction of the surface related phase component. A first approach into the understanding of rotational effects was achieved by the simulation of a rotating ship which resulted in a similar fringe pattern as observed in the interferogram.