Synthetic aperture radar residual range migration correction method

Abstract

The invention discloses a synthetic aperture radar residual range migration correction method. The method includes the following steps of firstly, obtaining two-dimensional echo signals, and conducting range-direction pulse compression through a conventional matched filtering method; secondly, conducting range migration correction on two-dimensional echo data obtained after the range-direction pulse compression is conducted; thirdly, conducting residual migration correction on the two-dimensional echo data where range migration correction is conducted, wherein the echo signals where the range migration correction is conducted are mocked up, the residual range migration correction is sequentially conducted on the pth line of azimuth data of the signals which are mocked up, p is larger than or equal to 2 and smaller than or equal to N, and N is the range-direction sampling number; fourthly, outputting a correction result. In the calculation process, no interpolation needs to be conducted, the data operation amount can be decreased, and the processing efficiency can be improved; under the data segmentation condition, the displacement amount of a staggered image in the space can be accurately estimated and corrected, the correction accuracy can reach the sub pixel level, and accurate and reliable data are provided for the subsequent high-accuracy imaging.

Description

Technical field [0001] The invention belongs to the field of radar technology, and particularly relates to a method for correcting residual range migration of synthetic aperture radar. Background technique [0002] Synthetic Aperture Radar (SAR) is an all-weather, all-weather two-dimensional high-resolution microwave remote sensing imaging radar. It has been widely used in the fields of earth remote sensing, resource exploration, reconnaissance, surveying and mapping, and disaster forecasting. The high resolution of the SAR range is obtained by transmitting a chirp signal with a large time-wide bandwidth product, and the high resolution of the azimuth is obtained by the Doppler effect produced by the relative movement between the radar and the target. The relative movement between the radar and the target, on the one hand, brings about the phase change in the azimuth direction; on the other hand, the echo delay of the same point target at different azimuth times is different, tha...

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Problems solved by technology

However, this method is carried out on the premise of reducing the resolution in the range direction, and the estimation accuracy of the residual range migration is usually poor

The document "D.Zhu,"SAR signal based motion compensation through combining PGA and 2-D map drift,"Conference on 2nd Asian-Pacific Synthetic Aperture Radar.pp.435-438,2009" divides the data into azimuth blocks, when The azimuth sampling point of each piece of data is small enough, and the residual distance migration within each piece of data can be ignored. Then, the distance sub-view correlation method is used to move each piece of data to the same distance resolution unit. However, the data block operation greatly reduces the processing efficiency.

The document "Gonzalez-Partida J-T, Almorox-Gonzalez P, Burgos-Garcia M, Dorta-Naranjo B-P, SAR System for UAV Operation with Motion Error Compensation beyond the Resolution Cell. Sensors.2008; 8(5):3384-3405" adopts The envelope alignment method in Inverse Synthetic Aperture Radar (ISAR) corrects the residual range migration in the time domain, and corrects the migration trajectory to the same range unit through interpolation processing. However, the interpolation processing requires a large amount of calculation and reduces the processing efficiency.

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