Distributed imaging with TerraSAR-X and TanDEM-X

This paper reports on several experiments performed with the TerraSAR-X (TSX) and the TanDEM-X (TDX) satellites. The experiments consist in the generation of improved image products by coherently combining the images acquired individually by both satellites, hence the name distributed imaging. In the literature it has already been suggested the use of two or more satellites in close formation not only to have interferometric capabilities, but also to improve the azimuthal or range resolutions by performing the acquisitions simultaneously (no temporal decorrelation). This idea can be carried out by acquiring different portions of the spectrum and adding them coherently afterwards. Another possibility is to synthesize quad-pol acquisitions using dual-pol ones, an idea already carried out with airborne systems. Such experiments have been performed with TSX and TDX and are described in this paper.