Abstract

The Inverse Synthetic Aperture Radar (ISAR) detects a target and becomes a two-dimensional image. In the current imaging Radar has a very important position. Its resolution has vertical resolution and lateral resolution. Where the angle of rotation of the detected object relative to the Radar Line of Sight (RLOS) determines its lateral resolution; the bandwidth of the radar transmitting signal determines its longitudinal resolution. In practice, if you want to have a higher resolution The target radar image can be achieved by increasing the magnitude of the rotation angle of the object to be detected relative to the direction of the Radar line of sight, that is, RLOS. The content of this research can be divided into three parts. The contents of this article are summarized as follows:

The first chapter mainly elaborates the development situation of ISAR at home and abroad. Discusses the content of this topic and research purpose. And illustrates the problems encountered by increasing the angle of rotation within the Radar imaging time in order to achieve a higher Radar lateral resolution to achieve this purpose.

The second chapter mainly introduces Radar imaging principle and commonly used algorithm. The ISAR turntable imaging model and distance - Doppler imaging algorithm are discussed. And then through the design of the algorithm after the simulation experiment to explore the different rotation angle of the target Radar imaging map, and analysis of different angles under the target based on the distance - Doppler algorithm under the effect of imaging, for the follow-up research to lay the foundation basis.

In the third chapter, two kinds of transverse scaling algorithms based on the imaging of the second chapter are introduced. Firstly, the principle of lateral scaling based on phase frequency parameter estimation is expounded, and the algorithm is realized. The principle of this algorithm is The radar echo signal is processed by the self-established reference signal, and the demodulated frequency signal is processed by the demodulation frequency signal. Then, the fast Fourier transform is performed and the energy is analyzed by the peak Distributed processing, processing is completed, the amplitude of its maximum value, you can get the corresponding signal frequency adjustment information, and then use the calculation method to estimate the radar target speed value to achieve lateral calibration. Secondly, in this chapter, we introduce another scaling algorithm - a horizontal scaling algorithm based on fractional Fourier transform. The algorithm differs from the previous algorithm, that is, the lateral scaling algorithm based on the phase frequency modulation parameter estimation, in that the two methods of obtaining the frequency estimation are not the same. Since FrFT has excellent detection capability for LFM signal, the algorithm is to perform FrFT transform on LFM signal so that the frequency of radar echo signal can be estimated, and then the target speed is obtained. So that the inverse synthetic aperture radar imaging can achieve the purpose of achieving lateral calibration. And then use the simulation experiment to get the calibration chart based on the above two algorithms respectively, and analyze the validity and real - time of the verification algorithm.

Keywords  Inverse Synthetic Aperture Radar,Range-Doppler FFT Algorithm, Phase Frequency Modulation Parameter Estimation,Cross-Range Scaling.

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