Azimuth ambiguity suppression method for along-track interferometric SAR current inversion

Abstract

The invention relates to an azimuth ambiguity suppression method for inversion of ocean currents by along-track interference SAR, which belongs to the technical field of marine remote sensing. The method registers the along-track InSAR two-channel SAR complex images corresponding to a certain area of ​​the sea surface where ocean currents are to be measured Transform to the range frequency-Doppler frequency domain; then use the independent and identically distributed samples of the range frequency dimension to calculate the covariance matrix of the along-track InSAR; then calculate the along-track interference signature entropy with the Doppler frequency The changing curve; according to the above curve, find the maximum points of the left half and right half of the curve respectively; then remove all Doppler units to the left of the maximum point on the left side of the curve and the right side of the maximum point on the right side of the curve All the Doppler units; then use the adaptive iterative method to determine the threshold of the characteristic spectral entropy; remove the Doppler units whose characteristic spectral entropy is greater than the threshold; finally, based on the obtained InSAR data, use the interferometry to calculate the range velocity of the ocean current.

Description

technical field [0001] The invention belongs to the technical field of marine remote sensing, and relates to an azimuth ambiguity suppression method suitable for along-track interferometric SAR for inversion of ocean currents in near-shore sea areas. Background technique [0002] Ocean current is one of the most basic and important elements in many processes in the ocean and meteorological fields, and it has restrictive effects on various biological, chemical and physical processes in the ocean. Ocean currents govern the movement of seawater around the globe, transporting and mixing nutrients, salts, gases, organisms and heat throughout the ocean. This means that understanding the existence, direction and speed of ocean currents has important implications for business, social services and scientific research. For example, industries such as oil and gas exploration require reliable ocean current data to ensure safe working conditions; ships need to rely on ocean current info...

AI Technical Summary

Problems solved by technology

However, this method has an obvious disadvantage: because some pixels are discarded in the SAR image domain, the flow field information in some areas will be lost

Therefore, this method is not suitable for sea surface scenarios and cannot be applied to flow field inversion

To sum up, so far, there is no effective along-track InSAR azimuth ambiguity suppression algorithm for ocean current inversion in the "near-shore" sea area.

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