Generalized-Capon Method for Diff-Tomo SAR Analyses of Decorrelating Scatterers

Fabrizio Lombardini,Francesco Cai

doi:10.3390/rs11040412

Abstract

In synthetic aperture radar (SAR) remote sensing, Differential Tomography (Diff-Tomo) is developing as a powerful crossing of the mature Differential SAR Interferometry and the emerged 3D SAR Tomography. Diff-Tomo produces advanced 4D (3D+Time) SAR imaging capabilities, extensively applied to urban deformation monitoring. More recently, it has been shown that, through Diff-Tomo, identifying temporal spectra of multiple height-distributed decorrelating scatterers, the important decorrelation-robust forest Tomography functionality is possible. To loosen application constraints of the related main experimented full model-based processing, and develop other functionalities, this work presents an adaptive, just semi-parametric, generalized-Capon Diff-Tomo method, first conceived at University of Pisa in 2013, for joint extraction of height and dynamical information of natural distributed (volumetric) scatterers, with its formalization and a series of insights. Particular reference is given to the important functionality of the separation of different decorrelation mechanisms in forest layers. Representative simulated and P-band forest data sample results are also shown. The new Diff-Tomo method is getting a flexible and rich decorrelation-robust Tomography functionality, and is able to profile height-varying temporal decorrelation, for significantly distributed scatterers.

Highlights

In Earth observation by multi-image synthetic aperture radar (SAR) remote sensing [1,2,3,4], in particular in coherent SAR data combination [3,4], Differential SAR Tomography (Diff-Tomo) viz. 4D (3D+Time) SAR Imaging [5] is an emerging SAR processing mode (University of Pisa patent)
After presenting the new generalized-Capon Diff-Tomo for non height compact decorrelating scatterers, main conclusions of the work are that the method appears to be effective and offering promising performance, as indicated by the simulated and real data tests, in particular for separation of temporal decorrelation mechanisms, and for decorrelation-robust Tomography
This can pave the way to large-scale characterization of vertical structure of temporal decorrelation in forest layers, to application of the decorrelation-robust Tomography processing to tall forest areas, and possibly to the future development of other dynamic information extraction applications in naturally distributed scattering scenarios

Summary

Introduction

In Earth observation by multi-image synthetic aperture radar (SAR) remote sensing [1,2,3,4], in particular in coherent SAR data combination [3,4], Differential SAR Tomography (Diff-Tomo) viz. 4D (3D+Time) SAR Imaging [5] is an emerging SAR processing mode (University of Pisa patent). After presenting the new generalized-Capon Diff-Tomo for non height compact decorrelating scatterers, main conclusions of the work are that the method appears to be effective and offering promising performance, as indicated by the simulated and real data tests, in particular for separation of temporal decorrelation mechanisms, and for decorrelation-robust Tomography. This can pave the way to large-scale characterization of vertical structure of temporal decorrelation in forest layers, to application of the decorrelation-robust Tomography processing to tall forest areas, and possibly to the future development of other dynamic information extraction applications in naturally distributed (volumetric) scattering scenarios

Space-Time Generalized Capon Method

Sample Simulated and P-Band Data Results