Modeling Based On Accurate Electromagnetic Scattering Center Imaging

The emergence of imaging Radar expanded the original concept of radar, it has the ability to image and identify the moving object (aircrafts, missiles, etc.), regional targets (mountains, cities, etc.), shows greater potential in microwave remote sensing applications in, provides people with more and more useful information. It also has a far-reaching impact and significance in national defense modernization and the development of national economy. Therefore, the radar imaging technology is being more and more international attention and concern, intense competition, rapid technological development areas.In recent years, the research of inverse synthetic aperture radar (ISAR) imaging is widespread concerned both at home and abroad, people had put forward a variety of motion compensation method and imaging algorithm. In order to overcome the difficulty of processing in radar signal transmit and receive, modern radars often works in high frequency. In high frequency, radar target scattering can be modeled by multiple scattering centers approximation. Therefore, the study of inverse synthetic aperture radar imaging is based on the model of multiple scattering centers. In this paper, the effectiveness of the scattering center model is explained from the perspective of electromagnetism.In addition, the effectiveness of the method required being tested by the measured data. However, the obtaining of the measured data is very difficult and takes a lot of time, manpower and material resources. Benefit from the development of computational electromagnetism, the numerical simulation can be used to obtain the imaging data. In this paper, it disscusses the main methods to compute the scatter data, it elaborates the method to obtain the time-domain back-wave by the frequency domain computational method.Because the general object of the inverse synthetic aperture radar is non-cooperated, motion compensation must be carried out before imaging. In this paper, it briefly introduces some of the current methods of movement compensation in and abroad, expounds the Distance-Doppler imaging principle of the rotating object, realizes the FFT and inverse projection imaging algorithm, inverse projection imaging algorithm is none angle-limited, but is computal costly, FFT is fast but the imaging data need be interpolated before imaging, then in this paper puts forward the NUFFT imaging algorithm based on FFT algorithm. It has reduced the interpolation process in FFT algorithm. In addition, in the paper, it also describes a single-frequency microwave imaging method, as well as has a discussion about the window function ant its impact in imaging. The methods have been verified by numerical examples in this paper.