High squint SAR curvilinear path wavenumber domain imaging method based on slope distance model

Abstract

The invention discloses a high squint SAR curvilinear path wavenumber domain imaging method based on a slope distance model, comprising: building a high squint SAR (Synthetic Aperture Radar) geometric model on a curvilinear path, selecting any point target Q, successively calculating an instantaneous slant distance R (ta) from an SAR aircraft to the point target Q, and a hyperbola instantaneous slant distance Re(ta) from the SAR aircraft to the point target Q, furthermore calculating the instantaneous slant distance R (X) from a high squint SAR aircraft on a curvilinear path to a point target, calculating distance frequency domain orientation time domain echo signals S (Kr, X) of a high squint SAR on a curvilinear path, furthermore successively calculating orientation time domain echo signals S<^> (Kr, X) of a high squint SAR on a curvilinear path after distance pulse pressure, and orientation time domain echo signals S (Kr, Kx) of a high squint SAR on a curvilinear path after fast fourier transform (FFT), setting an orientation resampling coefficient Kx-new, calculating orientation time domain echo signals S (Kr, Kx-new) of a high squint SAR on a curvilinear path after orientation resampling, furthermore calculating echo signals of a high squint SAR on a curvilinear path under a two-dimensional beam spectrum, successively performing range direction IFFT and azimuth IFFT, and obtaining high squint SAR imaging under a slope distance model.

Description

technical field [0001] The invention belongs to the technical field of radar signal processing, and in particular relates to a high squint SAR curve trajectory wave number domain imaging method based on a slant range model, which is suitable for high squint SAR imaging under a curved trajectory. Background technique [0002] With the improvement of Synthetic Aperture Radar (SAR) technology, more and more SARs are installed on various maneuverable platforms and small aircraft. However, due to the flexible movement of maneuverable platforms and small aircraft, and the movement trajectory under the action of acceleration presents a curve In addition, the traditional hyperbolic slant range model (HRM) is used to represent the slant range history of a point target in high squint SAR imaging under curved trajectories, which is very complicated and the accuracy is not high. [0003] In recent years, the wavenumber domain algorithm and various improved wavenumber domain algorithms h...

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Problems solved by technology

[0002] With the improvement of Synthetic Aperture Radar (SAR) technology, more and more SARs are installed on various maneuverable platforms and small aircraft. However, due to the flexible movement of maneuverable platforms and small aircraft, and the movement trajectory under the action of acceleration presents a curve The standard processing method based on the linear model cannot be fully applied; in addition, the traditional hyperbolic slope range model (HRM) is used to represent the slope range history of a point target in high squint SAR imaging under the curved trajectory, which is very complicated and the accuracy is not high

[0003] In recent years, the wavenumber domain algorithm and various improved wavenumber domain algorithms have been widely used in the data processing of high squint SAR ideal linear motion trajectory imaging; Some difficulties exist; among others, an improved slant distance model has been proposed that compensates for the approximate slant distance model by comparing the approximate rectilinear trajectory with the actual curved trajectory; however, the compensation is calculated for a reference target at the center of the scene , so the accuracy is high enough when the azimuth field of view is small, but the accuracy cannot meet the requirements when the azimuth field of view is relatively large

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