Different problems of space stereoscopic observation

Geometric aspects connected to along and cross-track stereoscopic observation from space using solid state linear arrays are discussed. In considering along-track viewing, the procedure adopted to simulate the geometric observation from the fore and aft sensors is described, and residual geometric errors, present in each pair of homologous ground lines, are examined. It is shown that the nature of the residual geometric errors, deriving mainly from the different projections of the fore and aft cameras on the Earth's ellipsoid, requires per line and per pixel corrections of the stereoscopic pair. For cross-track viewing, the geometric errors deriving from the perspectives relative to different orbits are computed. These perspectives cause a rotation between the steroscopic pair, and a considerable tangential scale distortion. The need to elaborate preprocessing systems which take into account the development of satellite position and attitude determination systems and use few ground control points is emphasized.