A parallelogram shaped arm for improving circular SARs

An existing instrumentation radar with 3D capabilities has been modified in order to achieve a more suitable aperture in the z-direction. The aperture being originally circular had as a draw back the fact that objects very soon left the real aperture of the antenna, hence resolution in height was rather poor. A parallelogram shaped arm was invented and implemented with the radar. Due to this technique it was possible to point the antenna over the whole aperture with a constant and adjustable angle with respect to the horizontal plane. The usable aperture has increased very much, hence the resolution increased. The proposed mechanical solution allows also a constant antenna gain for the acquired radar data and shows less problems due to depolarisation, in comparison with other circular apertures. The solution shows very good results, it appears to be an economic way for creation of synthetic aperture radars, that does not require any costly linear positioners. For the simplification of the data processing software, in particular for the SAR-processor, the possibility of not equally placed measurement points has been added to the instrument. This technique avoids interpolation of the data. Many experiments have been performed to validate the system and the implemented SAR processor. Some of these very promising results are presented