Radar moving object inhibition method in SAR image

Abstract

The invention discloses a radar moving object inhibition method in an SAR image, comprising steps of emitting a linear frequency modulation pulse signal by an SAR radar emission terminal, receiving linear a frequency modulation pulse signal by an m th channel of the SAR radar reception terminal so as to obtain an echo signal containing a radar moving object and a static object, successively performing distance pulse pressure processing, azimuth de-ramping operation and an azimuth FTT operation, obtaining a distance azimuth two dimension frequency domain signal containing the radar moving object and the static radar object so as to obtain the dynamic steering vector inhibiting the radar moving object, then obtaining a weight vector without the fuzzy clutter spectrum inhibiting the radar moving object signal, calculating energy of the radar moving object to obtain the echo signal of the inhibited static radar object, successively performing IFFT and azimuth de-ramping operation, obtaining the distance frequency domain azimuth time domain radar moving object echo signal after clutter is inhibited and successively performing the migration correction and the azimuth compression operation to obtain the SAR image after the radar moving object is inhibited.

Description

technical field [0001] The invention belongs to the technical field of radar signal processing, and in particular relates to a method for suppressing radar moving targets in SAR images, which is suitable for evaluating the SAR radar imaging quality of an airborne platform or a spaceborne platform. Background technique [0002] In recent years, due to the superiority of the high-resolution wide-swath (HRWS) SAR system, it has received more and more attention and research, and the multi-channel high-resolution wide-swath SAR along the azimuth The high-resolution wide-swath (HRWS) SAR system of the system can be used to solve the contradiction between high resolution and low pulse repetition frequency (PRF). In addition, since the spatial degrees of freedom along the azimuth can be used for clutter suppression, it also provides opportunities for radar moving target detection. [0003] Because the imaging method using a static scene usually causes the radar moving target to be ...

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Problems solved by technology

[0003] Because the imaging method using a static scene usually causes the radar moving target to be defocused in the obtained SAR image, and will focus the radar moving target to a wrong position, this is because the radar moving target is moving within the synthetic aperture time; In addition, due to the low azimuth sampling rate of the HRWSSAR system, a radar moving target will generate multiple ghost targets along the azimuth direction, and the radar moving target will focus on the wrong position, which will cover up the original system scene. Defocused radar moving targets affect researchers' understanding of SAR images

[0004] In response to this problem, the prior art discloses a space-time filtering method based on a traditional space-time adaptive processing framework, which is used to suppress radar moving targets in SAR images. However, based on the traditional space-time adaptive processing framework Requires a considerable degree of spatial freedom for suppressing radar moving targets in SAR images reconstructed by the HRWSSAR system

Theoretically, the spatial degree of freedom required to suppress radar moving targets is equal to the product of the number of moving targets in the system scene and the number of pulse repetition frequency (PRF) undersampling in the HRWSSAR system, which is difficult to meet in the actual system

Therefore, the traditional space-time adaptive processing framework severely limits the performance of space-time filtering processing methods

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