Bumpy platform SAR rapid time domain imaging method based on mixed coordinate system

Abstract

The invention discloses a bumpy platform SAR rapid time domain imaging method based on a mixed coordinate system. The method comprises the following steps of carrying out distance direction matching filtering processing on a baseband echo signal to obtain a distance-compressed signal; dividing a subaperture to construct a mixed coordinate system imaging grid; carrying out backward projection on each subaperture data on the mixed coordinate system imaging grid; and carrying out a rapid backward projection or rapid decomposition backward projection algorithm in the mixed coordinate system on a sub-aperture image in the mixed coordinate system to obtain an SAR image with a full spatial resolution. In the invention, a polar coordinate subaperture imaging grid in a rapid time domain algorithm is replaced with a mixed coordinate grid, a two-dimensional interpolation in the time domain imaging algorithm is optimized, execution efficiency of the time domain algorithm is improved, and a processing speed and imaging quality of the time domain algorithm are increased and improved.

Description

technical field [0001] The invention belongs to the technical field of SAR imaging, in particular to a fast time-domain imaging method for SAR on a bumpy platform based on a mixed coordinate system, which can be used for SAR imaging processing of bumpy platforms such as unmanned aerial vehicles. Background technique [0002] Synthetic Aperture Radar (SAR), as an active microwave active sensor, can obtain two-dimensional images of the observation scene all-time, all-weather, and long-distance, and has been widely used in various radar carriers. SAR imaging algorithms are mainly divided into two categories: frequency domain algorithms and time domain algorithms. Since the time-domain algorithm has no restrictions on imaging conditions and does not require pulse accumulation during the imaging process, it has gradually become a research hotspot in recent years. However, the computational complexity of time-domain imaging algorithm is relatively high, which leads to certain lim...

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Problems solved by technology

[0004]However, the FBP algorithm and FFBP algorithm polar coordinate sub-aperture image recursive fusion and the two-dimensional interpolation in the process of converting polar coordinates to Cartesian coordinates occupy a large part in the implementation process The specific gravity will inevitably increase the amount of calculation, and at the same time introduce interpolation errors, which will eventually affect the image quality, resulting in sidelobe elevation and integral sidelobe ratio performance deterioration, and there are certain limitations in practical applications

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