Experiment with Moving Target Focusing using GB-SAR

Abstract: Ground Based Synthetic Aperture Radar (GB-SAR) refers to SAR system which is mounted on ground linear track. It works on same principle as conventional SAR. Nowadays GB-SAR plays prominent role in the studies of many natural phenomenon as well as in studying some artificial infrastructure or terrain. It is a cost effective solution for the target scenes where it needed continuous monitoring. In this thesis GB-SAR system is experimented to detect moving targets. It should be emphasized that detection of moving target using GB-SAR is very new idea in the research field. As in conventional SAR, defocusing and/or displacement errors for moving target occur during image formation process in GB-SAR too. To detect the moving target, we need to test different Normalized Relative Speed (NRS) until the best focusing of moving target is reached. The research has been carried out in the following way. Firstly several simulations were tested on MATLAB with ideal condition. Secondly real experiments with moving targets were implemented based on the simulation results to collect real SAR data. Finally the data retrieved in the experiments was processed for moving target detection. The experiment was conducted at the Radio Communication Laboratory of Blekinge Institute of Technology. The radar is developed with a vector network analyzer (ENA 5071C), a double ridge guide horn antenna, a corner reflector, low loss high frequency cables and a antenna positioner. The movement of the radar is determined by a linear track. The developed GB-SAR system is configured as an ultra wideband–ultra wide beam (UWB) system. The operating frequency range is set to 1.5 - 2.5 GHz and the length of aperture is about 4 m. The radar measurement is taken place at 17 positions. The Global Back Projection (GBP) algorithm is used for UWB SAR data processing including image formation and moving target detection.