The Signal And Processing Of SAR

Synthetic Aperture Radar (SAR) imaging technique is well known by its unique advantage of all-weather and twenty-four-hour monitoring. It is made to be one of the most important technology in the remote sensing area since high resolution with large acquisition scene and the ability of penetrating the earth's vegetation. Nowadays, SAR plays a more and more important role in both civil business and military reconnaissance area. SAR imaging technique has been more and more recognized by many country with high technology. And it is a technology with competition and fast developing. This paper mainly focused on SAR'signal generating and processing. The main works can be listed as following:1) Discussed the shape of a point target response. It was said that the shape of a point target response is just a sinc function after imaging in synthetic aperture radar (SAR) systems. But this idea is mistaken actually. The shape of a point target response can be close to a sinc function shape under some limited conditions.2) Study the echo and image of a smooth plane. Since the counteraction of SAR echo of the inner scatter cells of a smooth plane, for example a flat plate, its SAR image may have a weak amplitude after formatting, except its edge. An investigation of the scattering from rectangular flat plates has been carried out to determine analytical formulations suitable for the estimation of radar cross section by simple physical optics theory. And Ross also concluded with an analytical description of vertical polarization cross section at the edge-on aspect. This paper describes the principle of SAR echo counteraction of smooth planes. And an analysis about reason and result is placed from the aspect of SAR signal processing. And the formulation of flat plate's RCS derived using this method has the same form with Ross's.3) A fast algorithm based on FFT is presented. Since it needs significant computation to simulate a large area distributed targets, it may speeds a lot of time, so it is very important to research a more efficient algorithm. Generally, the SAR raw signal is the appropriate superposition of returns from each facet. Noticeable, each return from every facet is the convolution of an impulse with specifically amplitude and phase and the transmitting signal of SAR. So we can calculate the superposition of each impulse from each facet first. And then we can get the Fourier Transform (FT) of returns from all facets by multiply the Fourier Transform of impulses and transmitting signal. Finally, the raw returns wave can be got by take an Inverse Fourier...