A circular track SAR reconstruction method based on mark point phase gradient extraction

Abstract

The invention provides a circular track SAR reconstruction method based on mark point phase gradient extraction. The method comprises the following steps: a plurality of mark points are selected from a scene, and ground horizontal plane coordinate system coordinates of a circular track SAR aerial carrier and the various mark points are obtained; according to the ground horizontal plane coordinate system coordinates of the circular track SAR aerial carrier and the various mark points, a phase gradient of each mark point is extracted from target echo signals received by the a circular track SAR, and real slope distance variances from the mark points to a real track is calculated according to the phase gradients; and through the utilization of the ground horizontal plane coordinate system coordinates of the circular track SAR aerial carrier and the various mark points and the slope distance variances of the mark points, a circular track SAR track is reconstructed. The above method solves a problem that present circular track SARs depend on high precision navigation measurement. The method not only can be used for the high precision track reconstruction of the circular track synthetic aperture radar, but also is applicable high precision track reconstruction of SARs of any track.

Description

technical field [0001] The invention relates to the field of radar signal processing, in particular to a circular SAR trajectory reconstruction method based on marker point phase gradient extraction, which is used for high-precision focused imaging of high-resolution airborne circular SAR. Background technique [0002] As an active remote sensing device, Synthetic Aperture Radar (SAR) has the advantages of all-time, all-weather, long-distance, high-resolution, and wide swath. In the distance direction, it obtains high resolution by transmitting large-bandwidth signals. In the azimuth direction, it uses the movement of the platform to construct an equivalent long antenna aperture to achieve high resolution in this direction. After nearly 60 years of development, SAR has become a mature space remote sensing technology and one of the important means of earth observation. [0003] Circular SAR (Circu1ar SAR, CSAR) is a SAR working mode proposed in the 1990s. It uses the SAR pla...

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Problems solved by technology

[0006] The purpose of the present invention is to provide a circular SAR trajectory reconstruction method based on the phase gradient extraction of marker points, which can solve the problem that the existing circular SAR relies on high-precision navigation measurement, and can provide technical support for realizing high-band circular SAR imaging

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