Method for optimizing SAR (Specific Absorption Rate) extended scene imaging on double-base forward-looking high-mobility platform

Abstract

The invention discloses a method for optimizing SAR (Specific Absorption Rate) extended scene imaging on a double-base forward-looking high-mobility platform. The method comprises the following main steps: obtaining an SAR time domain echo signal of a point target at first so as to obtain an echo signal and a range history after the linear moving amount is corrected, and then, carrying out azimuth FFT (Fast Fourier Transform) of the echo signal after the linear moving amount is corrected so as to obtain a two-dimensional frequency spectrum of the time domain echo signal; and carrying out high-order approximation of the range history after the linear moving amount is corrected, carrying out Taylor series development in the range direction after obtaining the phase term of the high-precision two-dimensional frequency spectrum after the linear moving amount is corrected, eliminating the phase space-variant property of the phase term of the high-precision two-dimensional frequency spectrum by adopting high-order polynomial fitting, carrying out range domain IFFT (Inverse Fast Fourier Transform) after obtaining a phase compensation signal having good focus in the range domain through a matching filter designed through the two-dimensional frequency domain, and then, obtaining focused SAR imaging through the matching filter designed in a range-Doppler domain.

Description

technical field [0001] The invention belongs to the technical field of radar imaging, and in particular relates to a method for optimizing SAR extended scene imaging of a bistatic forward-looking high maneuvering platform, that is, a method for optimizing synthetic aperture radar (Synthetic Aperture Radar, SAR) extended scene imaging of a bistatic forward-looking high maneuvering platform. It is suitable for extended scene imaging of bistatic forward-looking high maneuvering platform SAR or traditional airborne platform bistatic SAR. Background technique [0002] Bistatic forward-looking synthetic aperture radar (Synthetic Aperture Radar, SAR) can achieve two-dimensional high-resolution imaging of the target directly in front of the maneuvering platform due to its separate receiving and transmitting platforms and flexible geometric configuration. In recent years, due to the unique imaging mode of bistatic forward-looking high maneuvering platform SAR, the SAR imaging technol...

AI Technical Summary

Problems solved by technology

[0003] Bistatic forward-looking high-mobility platform SAR (BFHM-SAR) imaging technology is a typical application of bistatic forward-looking SAR in high-mobility platforms. Full two-dimensional high-resolution imaging, and has incomparable advantages in many specific and complex occasions. The distribution of targets is complex, and the islands and shores are densely populated, and the terrain background is complex, making it difficult for the existing monopulse radar angle measurement and single-base SAR imaging guidance methods to perform full-scale two-dimensional high-resolution imaging detection of complex background target areas, and it is also difficult to realize Effective separation of complex background targets; and the low interception characteristics and stealth capabilities of the dual-base forward-looking high-mobility platform SAR imaging technology can enable the bi-base forward-looking high-mobility platform SAR to achieve full-range two-dimensional imaging and autonomous homing during the dive and descent phase. Precise guidance, and the dual-base forward-looking high-mobility platform SAR has potential advantages in geological exploration, UAV cooperative operations, and missile active homing.

[0004] Compared with the airborne SAR, during the descent process of the bistatic forward-looking high maneuvering platform SAR, both the receiver and transmitter have higher speed and acceleration, and the double root form is introduced in the slant distance history of the receiver and transmitter. and high-order terms, so that the slant range history and Doppler parameters of the bistatic forward-looking high-maneuvering platform SAR show a more drastic change characteristic, which makes the traditional principle of stationary phase (Principle of Stationary Phase , POSP) cannot directly obtain the two-dimensional spectrum of the bistatic forward-looking high maneuvering platform SAR, which makes the subsequent SAR imaging processing more difficult

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