Synthetic Aperture RADAR is a radar imaging technique in which the relative motion of the sensor is used to synthesize a very long antenna and obtain high spatial resolution. The increasing interest of the scientific community to simplify SAR sensors and develop automatic system to quickly obtain a sufficiently good precision image is fostered by the will of developing low-cost/light-weight SAR systems to be carried by drones. Standard SAR raw data processing techniques assume uniform motion of the satellite and a fixed antenna beam pointing sideway orthogonally to the motion path, assumed rectilinear. In the same hypothesis, a novel blind data focusing technique is presented, able to obtain good quality images of the inspected area without the use of ancillary data information. Despite SAR data processing is a well established imaging technology that has become fundamental in several fields and applications, in this paper a novel approach has been used to exploit coherent illumination, demonstrating the possibility of extracting a large part of the ancillary data information from the raw data itself, to be used in the focusing procedure. Preliminary results are presented for ERS raw data focusing. The proposed Matlab software is distributed under the Noncommercial, Share Alike 4.0, International Creative Common license by the authors.