High-resolution wide-swath onboard SAR (synthetic aperture radar) real-time motion compensation algorithm

Abstract

The invention discloses a high-resolution wide-swath onboard SAR (synthetic aperture radar) real-time motion compensation algorithm which mainly includes an envelop compensation portion and a phase compensation portion. A traditional phase compensation algorithm is improved, and phase compensation can be finished before envelop compensation. Envelop compensation approximate treatment needs to divide distance sub-bands for echo signals after distance compression, so that motion error space varying is reduced. Therefore, interpolation operation of a traditional envelop compensation algorithm is avoided, and envelop compensation is finished by directly multiplying distance frequency domain with linear phase. Finally, distance sub-band images are spliced to obtain an imaging result of a whole swath. By the aid of an improved phase compensation algorithm, signal phase precision is ensured, so that the interpolation operation with large calculating amount can be more effectively avoided by rapid envelop compensation based on the distance sub-bands, and the real-time treatment performance of the algorithm is improved without affecting resolution.

Description

technical field [0001] The invention relates to the technical field of SAR imaging, in particular to an airborne SAR real-time motion compensation algorithm with high resolution and wide swath. Background technique [0002] An important problem in data processing of airborne SAR is the compensation of motion errors. Due to the interference of airflow and other factors during the flight of the carrier aircraft, the actual track is no longer an ideal straight line, and motion errors are introduced into the echo data. Motion errors have a greater impact on resolution, geometric linearity, contrast, etc., resulting in a serious decline in image quality. Therefore, motion compensation is a key step in airborne SAR data processing. [0003] The motion compensation algorithm is usually carried out in the two-dimensional time domain, which is divided into two parts: envelope compensation and phase compensation. The traditional motion compensation algorithm needs to perform envelo...

AI Technical Summary

Problems solved by technology

This range subband-based motion compensation algorithm brings another key problem: the target signal at the center of the non-subband is not corrected to the correct range unit, resulting in a residual envelope delay error; if the traditional phase error calculation formula is still used , will cause the phase compensation reference function to not match the real phase error, reducing the accuracy of phase compensation and affecting the final image quality

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