OFDM Based UWB Synthetic Aperture Through-wall Imaging Radar

Ultra wide band technology (UWB) is a new radio technology based on no sinusoidal waves, with very great bandwidths. UWB technology has double advantage: good capacity of penetration in building materials (concrete, brick, wood...), and high resolution (few centimetres) for radar applications. One of the most promising applications is the through the walls and the obstacles imaging, which has multiple outlets so much on the military level (at the time of attacks, taking of hostages...) that in the sector of civil safety (search for people under debris, in a fire...). This paper presents a feasibility study and a performance evaluation of portable UWB synthetic aperture radar (SAR) for through the walls imaging. Our system is based on multi-bands OFDM approach to ensure a double functionality of radar and communication, in possible remote operations. To obtain 2D radar images, back projection algorithm for time inversion was applied to SAR data. Modeling and simulation are carried out under Matlab/Simulink It was found that high resolution radar imaging (about 10 cm) are possible with a signal to noise ratio of -10 dB , for a radar system working below 3 GHz. Parameters such as UWB waveforms and number of OFDM carriers for an optimal radar system operation will also be discussed in this paper.