 | Pinheiro M.A. Multi-mode SAR interferometry for high-precision DEM generation: Diss. ... Dr.-Ing. / Deutsches Zentrum für Luft- und Raumfahrt, Institut für Hochfrequenztechnik und Radarsysteme, Oberpfaffenhofen. – K&oum;ln: DLR, 2017. - xxxi, 233 p.: ill. - (Forschungsbericht; 2017-2). - Res. also Germ. - Bibliogr.: p.213-232.
- ISSN 1434-8454
Шифр: (Pr 1120/2017-02) 02
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List of Figures ................................................ xx
List of Tables ................................................ xxi
List of Symbols and Acronyms ................................ xxiii
1 Introduction ............................................... 1
1.1 Motivation and scientific relevance of present work ........ 3
1.2 Problem formulation and context ............................ 6
1.3 Thesis contributions ....................................... 7
2 SAR Concepts ............................................... 9
2.1 Introduction to Synthetic Aperture Radar ................... 9
2.2 Nominal focusing .......................................... 12
2.3 SAR Interferometry ........................................ 13
2.3.1 Principles of across-track InSAR ................... 14
2.3.1.1 First order approximation of the
interferometrie phase .......................... 15
2.3.1.2 Statistics of the interferometrie phase ........ 16
2.3.1.3 Estimation of phase and coherence .............. 18
2.3.1.4 Decorrelation .................................. 20
2.3.2 Phase unwrapping ................................... 24
2.3.3 Phase calibration .................................. 25
3 Multi-channel SAR Interferometry .......................... 27
3.1 Wavelet approach for multi-baseline DEM generation ........ 27
3.2 Maximum-likelihood estimation for DEM generation .......... 29
3.3 Maximum-likelihood estimation with local planes ........... 30
3.4 Maximum α posteriori estimation for DEM generation ........ 32
3.5 The TanDEM-X dual-baseline phase unwrapping error
correction strategy ....................................... 34
3.6 Summary of existing techniques ............................ 36
4 Practical Issues Concerning Airborne SAR Interferometry ... 37
4.1 Motion errors and motion compensation ..................... 37
4.1.1 Interferometrie Phase Content After MoCo ........... 39
4.1.2 Recovering topography from the residual phase ...... 41
4.2 Residual motion compensation .............................. 42
4.3 Compensation of the multi-path effect ..................... 44
4.3.1 Model and simulation of the effect ................. 46
4.3.2 Mitigation of artifacts on phase using dual-
baseline information ............................... 53
4.4 Summary ................................................... 59
5 Dual-frequency and Dual-baseline Interferometry for
Accurate DEM Generation ................................... 61
5.1 On the choice of baseline and frequency configuration ..... 61
5.2 A new multi-channel framework for accurate DEM
generation ................................................ 64
5.3 Dual-frequency phase unwrapping ........................... 67
5.3.1 Region-growing unwrapping for dual-frequency
datasets ........................................... 70
5.3.2 Practical issues of the implementation ............. 79
5.4 Unwrapping error correction ............................... 79
5.4.1 Dual-frequency and dual-baseline detection and
correction ......................................... 82
5.4.2 Refinement with active contours .................... 86
5.4.3 Practical issues of the implementation ............. 96
5.5 Estimation of constant and linear baseline errors and
phase offset .............................................. 96
5.5.1 The repeat-pass baseline error model ............... 98
5.5.2 Estimating error model parameters .................. 99
5.5.3 Estimation in the complex domain .................. 103
5.5.4 Estimation given a reference DEM .................. 109
5.6 Phase-to-height conversion ............................... 112
5.7 Joint height estimation .................................. 114
5.7.1 Optimum spectral combination for removal of low-
frequency disturbances ............................ 116
5.7.1.1 Low-frequency disturbances in repeat-pass
interferometry ................................ 116
5.7.1.2 Removal of low-frequency disturbances ......... 118
5.7.1.3 Treatment of invalid data ..................... 121
5.7.2 Estimation of final height maps ................... 123
5.7.2.1 Maximum a posteriori estimation with total
variation regularization ...................... 124
5.7.2.2 DEM estimation in the wavelet domain .......... 127
5.8 Geocoding ................................................ 138
5.9 Summary .................................................. 138
6 F-SAR Experiments ........................................ 141
6.1 The DLR F-SAR system ..................................... 141
6.2 X- and S-band multi-baseline campaign over the North
Sea ...................................................... 142
6.2.1 Expected performance .............................. 144
6.2.2 Unwrapping ........................................ 147
6.2.3 Multi-path mitigation ............................. 151
6.2.4 Baseline calibration .............................. 153
6.2.5 Unwrapping error correction ....................... 155
6.2.6 Low-pass artifacts mitigation ..................... 157
6.2.7 Evaluation of the final DEM ....................... 157
6.3 Benefiting from the global TanDEM-X DEM to support the
chain: campaign over Kaufbeuren .......................... 167
6.3.1 Expected performance .............................. 170
6.3.2 Unwrapping ........................................ 173
6.3.3 Multi-path mitigation ............................. 175
6.3.4 Baseline calibration .............................. 177
6.3.5 Low-pass artifacts mitigation ..................... 179
6.3.6 Evaluation of the final DEM ....................... 181
6.4 Summary .................................................. 190
7 Experiments with large baseline TanDEM-X data ............ 191
7.1 Description of the case studies .......................... 192
7.2 Phase unwrapping with dual-channel region-growing ........ 194
7.3 DEM quality assessment ................................... 195
7.4 Summary .................................................. 204
8 Conclusions .............................................. 205
8.1 Summary and discussion ................................... 205
8.2 Outlook .................................................. 207
A Multi-phase evolution for image classification .............. 209
Bibliography .................................................. 213
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