Improved DEM maximum likelihood constraint multi-baseline InSAR phase unwrapping method

Abstract

The invention relates to an improved DEM maximum likelihood constraint multi-baseline InSAR phase unwrapping method. The method comprises the steps that: S1, multiple interferograms in the same area are acquired, and a probability density function corresponding to each homonymous pixel point is constructed for each interferogram; S2, the probability density functions corresponding to the homonymous pixels are combined according to a combination relationship, a joint probability density function can be obtained, and a phase value corresponding to a function maximum value in a certain interval is solved, so that a phase set can be formed; S3, a range of the phase set is calculated, and compared with a noise judgment threshold, and an external DEM is added at a pixel point greater than the noise judgment threshold to realize constraint; and S4, a maximum solution of the joint probability density function corresponding to different pixel points is solved, so that a final unwrapping phase can be obtained. Compared with the prior art, the method has the advantages that the method can effectively inhibit noise influence, reduce the dependence on the external DEM, and can obtain inversionresults with higher precision.

Description

technical field [0001] The invention relates to a multi-baseline InSAR phase unwrapping technology, in particular to an improved DEM maximum likelihood constrained multi-baseline InSAR phase unwrapping method. Background technique [0002] Synthetic aperture radar interferometry (Interferometry Synthetic Aperture Radar, InSAR) technology has developed rapidly in recent years, but the traditional single-baseline InSAR technology is still affected by atmospheric effects and geometric distortion. Baseline length also affects the complexity and accuracy of phase unwrapping. When the length of the spatial baseline is short, the corresponding phase interference fringes are relatively sparse, and the phase unwrapping is relatively easy, but the corresponding digital elevation model has low precision. On the contrary, although the phase interference fringes of the long baseline are relatively dense and the corresponding phase unwrapping is complicated, the corresponding digital ele...

AI Technical Summary

Problems solved by technology

Although there have been some scientific research results in the research of multi-baseline InSAR data processing in China, most of the experimental research levels are still in their infancy. The existing multi-baseline InSAR technology is mostly based on simulation experiments. Technology still needs to be perfected

For example, the unwrapping accuracy of the multi-baseline InSAR algorithm based on differential phase is greatly affected by the unwrapping accuracy of the shortest baseline interferogram, and there is a problem of error accumulation; The maximum likelihood estimation method has the disadvantages of large unwrapping errors when the signal-to-noise ratio is low, and serious glitches in the inversion results

Images