Sub-aperture Forward Squint High-Order Nonlinear Frequency Modulation Scaling Imaging Method for Missile-borne SAR

Abstract

The invention belongs to the field of radar signal processing, and discloses a missile-borne SAR sub-aperture forward squint high-order nonlinear chirp scaling imaging method. According to the method, missile-borne SAR forward squint high-order nonlinear chirp scaling imaging is achieved through sub-aperture data, and the method can be used for SAR imaging of airborne platforms or missile-borne platforms. The method mainly includes the steps of firstly, conducting distance pulse pressure and time domain walking correction on an echo signal; secondly, converting the signal into the two-dimensional frequency domain, conducting frequency domain migration correction and secondary compression, and compensating for the high order phase in the orientation direction; thirdly, leading high-order nonlinear chirp scaling disturbance factors into the orientation frequency domain, and correcting the space variability of the Doppler frequency modulation and the high-order terms in the orientation direction; fourthly, focusing an image on the orientation frequency domain through spectrum analysis. The method solves the problem of decoupling of distance orientation and the orientation focus depth problem caused by time domain walking correction, and the method can meet the requirements for different scenes and high resolution and can be used for the field of ground mapping and other fields.

Description

technical field [0001] The invention belongs to the field of radar signal processing, and relates to a high-order non-linear FM scaling imaging method for a missile-borne SAR sub-aperture forward squint, which utilizes sub-aperture data to realize a high-order (third order and above) nonlinearity of a missile-borne SAR forward squint Frequency modulation and scale imaging can be used for SAR imaging on airborne and missile-borne platforms. Background technique [0002] With the development of synthetic aperture radar imaging technology, missile-borne SAR combining synthetic aperture radar (SAR) with precision guidance technology has become a research hotspot in recent years. Since the missile-borne SAR requires high resolution to obtain more target information, the shape and fine structure of the target can be presented more clearly, thereby greatly improving the ability to identify the target and the ability to strike accurately; and in the military, the missile-borne SAR ...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a missile-borne SAR sub-aperture forward squint high-order non-linear frequency modulation scaling imaging method, which can solve the problem of azimuth focus depth caused by decoupling of distance and azimuth and time domain correction, and improve imaging accuracy. Improved the focus effect of edge points and expanded the imaging scene

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