Multi-ship target SAR and ISAR hybrid imaging method of airborne radar

Abstract

The invention discloses a multi-ship target SAR and ISAR hybrid imaging method of an airborne radar. The method is characterized in that a geometric model of an airborne squint SAR to sea surface ship target imaging is established and an instantaneous slant distance R(ta) expression of a sea surface ship target; the airborne squint SAR emits a chirp signal so as to acquire original echo signal s(t; ta) of the airborne squint SAR, and range direction FFT, linear distance walking correction and range direction pulse pressure are successively performed on the s(t; ta) so as to acquire the original echo signal of the airborne squint SAR after pulse pressure; then two-dimensional de-sloping processing and azimuth direction phase compensation are successively performed on the original echo signal so as to acquire coarse focus imaging S0 of the airborne squint SAR, and then morphological offset is performed so as to acquire an airborne SAR binary image S2 after the morphological offset; ship target boundary detection is performed on the S2 so as to extract D ship targets, and then envelope alignment, phase focusing, rotated migration though resolution cell correction and frequency distribution estimation corresponding to intermediate time of orientation slow time ta are successively performed so as to acquire final ISAR imaging of the D ship targets.

Description

technical field [0001] The invention belongs to the technical field of SAR and ISAR hybrid imaging, in particular to a multi-ship target SAR and ISAR hybrid imaging method for airborne radar, that is, a multi-ship target synthetic aperture radar and inverse synthetic aperture radar hybrid imaging method for airborne radar , suitable for accurate imaging of multi-ship targets. Background technique [0002] With the development of science and technology, and in order to cope with future information warfare, more and more countries have begun to vigorously develop maritime defense forces; among them, maritime ships, as an important tool for implementing maritime strategies, perform maritime reconnaissance, combat, etc. Important functions have become the focus of the new maritime defense system. At the same time, the development of maritime ships plays an important role in obtaining intelligence in a timely manner and ensuring the success of military operations. [0003] The m...

AI Technical Summary

Problems solved by technology

In addition, due to the different motion characteristics of multiple ship targets, it is impossible to use SAR alone to simultaneously image multiple ship targets; For multiple ship targets, if the ISAR imaging is used alone, it is impossible to separate the echo signal of each ship target from the mixed echo in the range and azimuth direction, and it is also impossible to simultaneously detect each ship target. motion compensation

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