Frequency-domain migration-based de-chirping inverse synthetic aperture radar (ISAR) envelope alignment method

Abstract

The invention relates to a frequency-domain migration-based de-chirping inverse synthetic aperture radar (ISAR) envelope alignment method. According to the method, based on the alignment of a conventional envelope correlation method, the accuracy of envelope alignment is improved by using the frequency-domain migration property of Fourier transform; and the maximum constraint condition of the accuracy of traditional envelope alignment is that the error of migration alignment cannot break through the limitation of half of a range resolution cell when migration alignment is carried out under a condition that time-domain signal sampling is completed, and the solidification of range units is completed, wherein one range unit is one complex data representation. Since FFT operation is required to be carried out before the formation of range units in de-chirping signal processing, echo signals are multiplied by a frequency shift factor before the FFT operation, and accurate migration of data which have been subjected to FFT can be realized.

Description

technical field [0001] The invention belongs to an ISAR radar imaging method, and relates to an ISAR envelope alignment method of a deskewing radar. Background technique [0002] Using the turntable model to analyze inverse synthetic aperture radar imaging, the quality of translation compensation will have a significant impact on the imaging quality. Motion compensation is generally implemented in two steps: envelope alignment and initial phase correction: envelope alignment cyclically shifts the one-dimensional range image so that the echo signals of the same scattering point in different pulses are in the same distance unit; phase compensation eliminates the Doppler phase shift due to translational motion. Envelope alignment takes the distance resolution unit as the shift unit step size, the previous echo as the reference, and the latter echo data is correlated with the reference after moving one distance unit each time, and the maximum correlation peak value is used as t...

AI Technical Summary

Problems solved by technology

Therefore, many scholars are committed to using the distance super-resolution algorithm to improve the distance resolution to achieve the purpose of improving the accuracy of envelope alignment, such as the minimum entropy distance super-resolution method, deconvolution distance super-resolution method, etc. The above algorithms not only have a large amount of calculation, but also It is not conducive to engineering applications, and requires an accurate model of the signal and a sufficiently high signal-to-noise ratio. Currently, there are few engineering applications

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