InSAR (Interferometric Synthetic Aperture Radar) long and short baseline fusion phase estimation method based on phase derivative variance

Abstract

The invention discloses an InSAR (Interferometric Synthetic Aperture Radar) long and short baseline fusion phase estimation method based on a phase derivative variance. The increase of the baseline length in an InSAR system can improve the height measurement precision, but also can increase the difficulty of phase unwrapping. Therefore, the advantages of the long and short baselines are brought into full play, the phase estimation precision is improved by utilizing the complementary information of the same scene obtained by the long and short baselines, and the discontinuous region pixel points of the long and short baselines are accurately marked based on the phase derivative variance. On the basis, different fusion methods are adaptively selected by utilizing the continuation property of the pixel points in the respective absolute phases of the long and short baselines, so that the estimation of the absolute fusion phase of the long baseline is realized. Through simulation verification, the method provided by the invention can effectively suppress unwrapping errors caused by noise, and remarkably reduce the number of jump points. Compared with a traditional multi-baseline maximum likelihood phase unwrapping algorithm, the operation efficiency is remarkably improved, and finally, the estimation precision and robustness of the domain fusion absolute phase of the long baseline are improved.

Description

technical field [0001] The invention relates to the field of synthetic aperture radar interference processing, in particular to an InSAR long-short baseline fusion phase estimation method based on phase derivative variance. Background technique [0002] The Synthetic Aperture Radar (SAR) system has developed into a very important microwave remote sensing detection technology, which realizes active observation of the ground by emitting radar waves. Because radar waves are in the microwave band and have strong penetrating capabilities, they have the unique advantage of being able to work around the clock and around the clock. Synthetic Aperture Radar Interferometry (InSAR) is a combination of SAR imaging technology and interferometric technology, by obtaining two or more SAR image phase information relative to the same area and the geometric relationship of the terrain, so as to efficiently obtain large-area terrain Elevation information is one of the main means of topographi...

AI Technical Summary

Problems solved by technology

[0005] The existing multi-baseline InSAR phase unwrapping techniques mainly include the following categories. The first type is the multi-baseline maximum likelihood phase unwrapping algorithm. Its principle is to use the interferometric phase probability density function under different baselines to analyze each The interferometric phase of pixels achieves maximum likelihood estimation, but the phase estimation accuracy of this algorithm is affected by the SAR operating frequency, coherence coefficient and the number of interferograms. When the coherence coefficient is low or the number of interferograms is large, the phase noise will increase accordingly , the use of multi-baseline maximum likelihood phase unwrapping will produce large errors or even fail; the second type is the multi-baseline maximum a posteriori phase unwrapping algorithm. However, the limitations of this type of algorithm lie in the long operation time and high memory pressure of the maximum a posteriori estimation algorithm under multiple baselines.

The third type is to use the relationship between the multi-baseline interferometric phase and the fuzzy number for phase unwrapping, mainly the Chinese remainder theorem and its improved algorithm, but this method has poor noise robustness and cannot be applied in practice

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