Method for compensating high-frequency motion error of unmanned aerial vehicle-mounted bistatic synthetic aperture radar (SAR)

Abstract

The invention discloses a method for compensating a high-frequency motion error of an unmanned aerial vehicle-mounted bistatic synthetic aperture radar (SAR), and the method comprises the steps: constructing a high-frequency motion error model of an unmanned aerial vehicle-mounted bistatic SAR system, and determining the amplitude and initial phase spatial-variant properties and spatial-variant gradient directions of the high-frequency motion error model; then, using a traditional parameter estimation method to estimate amplitude and initial phase information of a high signal-to-noise ratio region in a whole scene, projecting the amplitude and initial phase information to a space-variant gradient direction, and using a fitting method to obtain amplitude and initial phase information of all positions in the space-variant gradient direction; and performing sub-scene division on the whole scene, and performing high-frequency motion error compensation on each sub-scene so as to realize high-frequency motion error compensation of the whole scene. According to the method, the projection and fitting modes are adopted, only the amplitude and initial phase information of the high-frequency motion error of the high-signal-to-noise-ratio area need to be estimated, the calculation amount is reduced, the operation efficiency is improved, the sub-scene division mode is adopted, and the compensation efficiency and precision are improved compared with the mode that motion error compensation is directly conducted on the whole scene.

Description

technical field [0001] The invention relates to the technical field of bistatic synthetic aperture radar, in particular to a high-frequency motion error compensation method for unmanned aerial vehicle-borne bistatic SAR. Background technique [0002] Compared with the traditional large aircraft-borne system or space-borne system, the UAV-BiSAR (Unmanned Aerial Vehicle Bistatic Synthetic Aperture Radar) system is more susceptible to vibrations caused by the environment during flight, causing trajectory errors ;Compared with the single-base system, the UAV-BiSAR system has double the source of motion error, and the trajectory error of the transceiver should be considered during motion compensation; The high-frequency errors with similar frequencies have obvious space variation phenomenon, and the two will be seriously coupled, and the space variation will be more complicated, which greatly increases the difficulty of subsequent motion error compensation processing. [0003] T...

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Problems solved by technology

[0002] Compared with the traditional large aircraft-borne system or space-borne system, the UAV-BiSAR (Unmanned Aerial Vehicle Bistatic Synthetic Aperture Radar) system is more susceptible to vibrations caused by the environment during flight, causing trajectory errors ;Compared with the single-base system, the UAV-BiSAR system has double the source of motion error, and the trajectory error of the transceiver should be considered during motion compensation; The high-frequency errors with similar frequencies have obvious space variation phenomenon, and the two will be seriously coupled, and the space variation will be more complicated, which greatly increases the difficulty of subsequent motion error compensation processing

[0003] The traditional motion error compensation method uses the self-focusing algorithm with iterative parameter adjustment. This type of algorithm requires strong point information in the scene, and is mainly aimed at a single space-varying direction, with a large amount of calculation.

In the bistatic system, the trajectory of the UAV is greatly affected by the environment when flying, and the bistatic leads to motion error coupling. In the case of changes in the direction of space change, the compensation efficiency is low, and the compensation effect is poor.

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