Marine dynamic information extraction method on basis of SAR (Synthetic Aperture Radar) sub-aperture sequence images

Abstract

The invention discloses a marine dynamic information extraction method on the basis of SAR (Synthetic Aperture Radar) sub-aperture sequence images and relates to a SAR technology. The marine dynamic information extraction method on the basis of the SAR sub-aperture sequence image comprises the following steps of: (A) carrying out sub-aperture imaging processing on SAR echo data to obtain the sub-aperture sequence images; (B) after carrying out characteristic extraction and meshing on each sub-aperture sequence image, carrying out sea surface dynamic information extraction for once on each twoadjacent sub-aperture sequence images to obtain characteristic movement speeds Vx (S, T) and Vy (S, T) of each grid; and (C) averaging results obtained by repeatedly extracting and reducing the errorand the noise to obtain marine dynamic information. The method disclosed by the invention is simple, is easy to operate, has wide application range and can be used for accurately extracting the dynamic information of the sea surface.

Description

technical field [0001] The invention relates to the technical field of synthetic aperture radar (SAR), and relates to a method for extracting ocean dynamic information based on SAR sub-aperture sequence images. Background technique [0002] Synthetic Aperture Radar (SAR) is an active microwave remote sensing method developed in the late 1950s. Compared with other remote sensing methods, it has a large detection range, high resolution, all-time, all-weather, and the resolution does not change with the slant distance. It has been successfully applied in many fields. SAR is an indispensable and important means of remote sensing, especially in the remote sensing detection of areas such as the ocean with a large detection range and large cloud and fog interference. The world's first spaceborne SAR——SeaSAT was applied to ocean remote sensing. Later, many SAR satellites launched successively, including ERS-1 / 2, RADARSAT-1 / 2, EnviSAT, etc., have a large number of successful ocean r...

AI Technical Summary

Problems solved by technology

On the other hand, the classic SAR imaging theory requires that the target remains unchanged within the synthetic aperture time, and the time-varying period of many dynamic information in the ocean is often shorter than the synthetic aperture time. At present, the signal processing methods of marine SAR data often directly apply fixed The SAR processing method of the target, so it is easy to lose some fast-changing information

The synthetic aperture time of SAR depends on the length of the azimuth antenna, the platform speed and the electromagnetic wavelength. With the continuous improvement of the SAR resolution index, the synthetic aperture time is also continuously improved. For example, the synthesis of the L-band SAR with the meter-level resolution of the airborne SAR The aperture time has been as long as 30 seconds or even longer. If the SAR signal processing method with a fixed target is directly used, the dynamic information with a time-varying period of less than 30 seconds will be lost, which cannot meet the requirements of wave imaging with a wavelength of hundreds of meters (deep water The vibration period of 500 wavelength waves in sea area is about 18 seconds)

This is also the main reason why airborne L-band SAR images often cannot see waves with wavelengths less than 100 meters, although the rated resolution can reach the meter level or even higher

Therefore, directly applying the SAR information processing method of land targets to deal with ocean dynamic targets will lose a lot of sea surface dynamic information

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