SAR imaging method and system based on synthetic bandwidth frequency scaling

Abstract

The invention discloses an SAR imaging method and system based on synthetic bandwidth frequency scaling, which relates to the field of microwave imaging detection. Through a baseband frequency domain synthesis technology, a plurality of narrowband linear frequency modulation signals are transmitted into a repetition frequency area, narrowband target echo signals returned by the repetition frequency area are synthesized into broadband echo signals according to a baseband complex signal sequence, and the broadband echo signals are obtained on the basis that the cost of an inherent microwave transmitting end hardware structure is not increased; on the premise that a motion compensation algorithm is not adopted, the problems of distance bending space-variant and distance orientation coupling under a large squint angle are solved through a frequency scaling wave number domain imaging processing algorithm, and the complexity and response delay of the system are reduced. According to the method, bending correction is carried out by adopting FFT operation and phase function complex multiplication on distance bending space-variant correction through a frequency scaling technology, interpolation operation of an RD algorithm and a PFA algorithm is avoided, the operand is saved, and the method can be applied to some application scenes with high real-time performance requirements.

Description

technical field [0001] The invention relates to the field of microwave imaging detection, in particular to a method and system for SAR imaging based on synthetic bandwidth frequency scaling. Background technique [0002] With the continuous development of microwave detection technology, different forms of imaging technology are also emerging, the most dazzling of which is undoubtedly the SAR technology. [0003] In 1978, NASA launched the world's first spaceborne SAR satellite: SEASAT satellite; the launch of SEASAT satellite announced the importance of SAR technology and demonstrated to the world the ability of SAR to obtain high-definition surface images. Since then, SAR has become an important part of the modern microwave detection field. [0004] SAR (Synthetic Aperture Radar), that is, synthetic aperture radar, is an active earth observation system that can be installed on platforms such as aircraft, satellites, and spacecraft, and can achieve all-weather and all-weath...

AI Technical Summary

Problems solved by technology

[0014] 1. Since there is still a certain distance between SAR and optical remote sensing in terms of resolution, it is necessary to improve the resolution of SAR images through technical means, and increasing the image resolution will inevitably lead to an increase in hardware costs or system complexity;

[0015] 2. A large amount of computing power is required to achieve a wide range of oblique viewing angles, and an accurate motion compensation algorithm is required to improve platform stability, which will inevitably increase R&D costs and hardware costs;

[0016] 3. When the accuracy and other requirements are met, the complexity of the algorithm will inevitably increase, resulting in a decrease in the robustness and real-time performance of the system;

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