Imaging Of Target Scattering Using Fully Polarimetric FMCW Radar System And Isar Reconstruction

According to the working principle of radar and the different methods of imaging, imaging radar can be divided into synthetic aperture radar (SAR) and inverse synthetic aperture radar (ISAR). It is synthetic aperture radar when the movement of the radar platform is related to the fixed targets. On the other hand, it is known as inverse synthetic aperture radar (ISAR) if the movement of the targets is based on the radar platform, which is also equivalent to a reverse movement and form arrays, accordingly can also be used for target imaging.A fully polarimetric synthetic aperture radar (SAR) system with moving platform is constructed for experimental measurement and imaging of target scattering in an anechoic chamber of the Laboratory. This system operates the frequency modulated continuous wave (FMCW). Using the fractional Fourier transform (FRFT), the radar echoes can be turned to chirp signal in both range and azimuth directions via FFT and optimal order FRFT, respectively, and compressed to an impulse function. The experiments show polarimetric scattering images from a tank-like model under different incident angles, which is calibrated by RCS of tri-angular reflector. Numerical FEKO is also applied to validation of scattering and imaging results.ISAR to a moving target of space (satellite), as well as, two or three-dimensions reconstruction of the target is the important foundations of space research and application technology. It is very important to improve the efficiency of the imaging of the space target. The electromagnetic scattering model is the basic of the imaging method. The method called Bidirectional Analytical Ray Tracing (BART) which calculates the scattering of large complex space targets, traces the ray from the incident direction and inverse direction separately from the incident direction. It quickly calculates three-dimensional scattering of the target by ray tracking technology, which makes the problem of computational complexity which had nothing to do with electrical size. The method of BART, to a certain extent, can fast calculate the scattering of three-dimensional electrical large target, reduces the amount of calculation, shorten the time of the calculation, which makes the possible to real-time space target recognition.