Method for eliminating time-varying blurring effect in sea level synthetic aperture radar imaging

Abstract

The invention relates to a method for eliminating time-varying blurring effect in sea level synthetic aperture radar imaging, which comprises: primarily imaging sea level SAR back waves by using a conventional SAR imaging algorithm to acquire an SAR sea level image with the time-varying blurring effect; estimating an azimuth wave number epsilon0 and a range wave number eta0 of a wave principal component in the SAR sea level image by using wave spectrum inversion; calculating an azimuth speed correction value 1 / 2*g<1 / 2>*epsilon0*(epsilon0<2> + eta0<2>)<-3 / 4> and a range speed correction value 1 / 2*g<1 / 2>*eta0*(epsilon0<2> + eta0<2>)<-3 / 4> of an SAR platform according to the dispersion relations of the sea level waves, and constructing a corrected matched filter according to the azimuth and range correction values; and matching and filtering the sea level back waves by using the corrected matched filter to finish SAR imaging so as to eliminate the time-varying blurring effect. The method utilizes the dispersion relations of the wave vibrating frequency and the wave number to correct the azimuth matched filter of the SAR so as to eliminate the SAR image blurring effect brought by the random time-varying property of the sea level, improve the definition of the SAR sea image, and acquire and invert the sea information with higher precision from the SAR image.

Description

technical field [0001] The invention belongs to the technical field of remote sensing, and relates to a method for eliminating time-varying fuzzy effects in sea surface synthetic aperture radar imaging. Background technique [0002] Synthetic Aperture Radar (SAR) is an important ocean remote sensing method. Compared with other remote sensing methods, SAR has the advantages of all-time, all-weather and high resolution. SAR has been successfully applied in the ocean field. A lot of ocean information can be obtained from SAR images, such as inversion of ocean waves, ocean currents, wind fields, internal waves and even submarine terrain. The world's first SAR satellite-SeaSAT is Satellites for marine applications. [0003] The microwave scattering on the sea surface is mainly due to the Bragg scattering effect: the microwave scattering on the sea surface mainly depends on the amplitude of a certain scale wave on the sea surface, the propagation direction of the wave is parallel...

AI Technical Summary

Problems solved by technology

[0014] The principle of SAR imaging requires that the scattering coefficient of the target remains unchanged within the synthetic aperture time, but the sea surface is dynamic and time-varying, and its time-varying period is equivalent to or even smaller than the synthetic aperture time, which will cause time-varying ambiguity. The current SAR imaging method is difficult to obtain clear sea surface images, making it difficult to obtain some detailed ocean information

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