 | Almeida F.Q de. Multichannel staggered SAR for high-resolution wide-swath imaging: Diss. ... Dr.-Ing. / Deutsches Zentrum für Luft- und Raumfahrt, Institut für Hochfrequenztechnik und Radarsysteme, Oberpfaffenhofen. - Köln: DLR, 2018. - xvi, 259 p.: ill. - (Forschungsbericht; 2018-03). - Res. also Germ. - Bibliogr.: p.247-259. - ISSN 1434-8454
Шифр: (Pr 1120/2018-03) 02
|
Zusammenfassung ................................................ vi
Abstract ...................................................... vii
Acronyms and Symbols ......................................... viii
1 Introduction ............................................... 1
1.1 State-of-the-Art Spaceborne Synthetic Aperture Radar
Missions ................................................... 3
1.2 Motivation ................................................. 7
1.3 Scope and Structure ........................................ 9
1.4 Main Contributions ........................................ 10
2 Conventional SAR .......................................... 12
2.1 Chapter Overview .......................................... 12
2.2 Synthetic Aperture Radar: Basic Principle ................. 12
2.3 Limitations and Constraints ............................... 15
2.3.1 Ambiguities and the Trade-off between Swath Width
and Azimuth Resolution ............................. 15
2.3.2 Blind Ranges ....................................... 21
2.4 Overview of Spaceborne SAR Modes and High-Resolution
Wide-Swath (HRWS) SAR Techniques .......................... 23
2.5 Remarks on Conventional SAR ............................... 29
3 HRWS SAR .................................................. 30
3.1 Chapter Overview .......................................... 30
3.2 Multichannel SAR in Azimuth ............................... 30
3.3 Staggered SAR ............................................. 38
3.3.1 Rationale and Motivation ........................... 38
3.3.2 Definition and Timing Analysis of PRJ Sequences .... 40
3.3.3 A Brief Discussion of Sequence Design .............. 54
3.4 Remarks on HRWS SAR ....................................... 63
4 Multichannel Staggered SAR in Azimuth ..................... 64
4.1 Chapter Overview .......................................... 64
4.2 Problem Overview .......................................... 64
4.3 Azimuth Phase Steering .................................... 67
4.4 The Virtual Beam Synthesis (VBS) Method ................... 77
4.4.1 General Framework .................................. 77
4.4.2 Optimal Mean Square Error (MSE) Criterion .......... 84
4.4.3 Optimal Signal to Noise Ratio (SNR) Criterion ...... 88
4.4.4 Joint MSE-SNR Optimization Criterion ............... 91
4.4.5 Iterative Pattern Synthesis: Update of the Goal
Patterns to Equalize Performance over the Grid ..... 94
4.5 Peculiarities of Planar Direct Radiating Arrays ........... 97
4.6 Remarks on Multichannel Staggered SAR in Azimuth ......... 106
5 Simulation Examples: Analysis and Comparison of Methods .. 108
5.1 Chapter Overview ......................................... 108
5.2 Description of Simulation Scenario ....................... 108
5.3 Synthesis of a Single Goal Pattern: The Impact of the
SNR Sensitivity Parameter a .............................. 113
5.4 Synthesis of Full Output Grid: Comparison between
Methods .................................................. 117
5.4.1 Output Pattern Analysis ........................... 117
5.4.2 Impulse Response Function Analysis ................ 125
5.5 Remarks on Simulation Examples ........................... 129
6 System Design Examples ................................... 130
6.1 Chapter Overview ......................................... 130
6.2 Reflector Systems in Single Polarization ................. 131
6.2.1 Tandem-L High-Resolution 3.0 m Mode ............... 131
6.2.2 Very High Resolution Wide Swath Mode .............. 135
6.3 Fully Polarimetrie Reflector System ...................... 139
6.4 Planar System in Single Polarization ..................... 143
6.5 Data Rates and Onboard Implementation Complexity ......... 148
6.6 Remarks on System Design Examples ........................ 158
7 Proof of Concept with Ground Based Radar Demonstrator .... 159
7.1 Chapter Overview ......................................... 159
7.2 The MIMO Demonstrator and the Experimental Setup ......... 159
7.3 Signal Processing and Calibration ........................ 163
7.4 Results and Reconstruction Quality Assessment ............ 170
7.4.1 Resampling and Reconstruction of original data .... 170
7.4.2 Resampling with added Synthetic Noise ............. 175
7.5 Remarks on the Proof of Concept .......................... 177
8 Analysis of Errors and Mismatches ........................ 178
8.1 Chapter Overview ......................................... 178
8.2 Pattern Mismatch due to Pulse Extension over Range ....... 179
8.3 Pattern Mismatch due to Limited Update of Weights over
Range .................................................... 183
8.4 Pattern Mismatch due to Pulse Bandwidth .................. 185
8.5 Pattern Mismatch due to Mispointing ...................... 193
8.6 Pattern Mismatch due to Pattern Uncertainty .............. 196
8.7 Effect of Phase and Amplitude Errors on Weights .......... 204
8.8 Remarks on the Analysis of Error and Mismatches .......... 210
9 Conclusion ............................................... 213
9.1 Thesis Objectives and Results ............................ 213
9.2 Outlook of Further Work .................................. 215
Appendix A: Elevation Beamforming Techniques .................. 218
Appendix A. 1: The Sidelobe Constrained Beamformer ............ 218
Appendix A.2: Example and Comparison to Other Methods ......... 222
Appendix B: SAR Performance Indices ........................... 231
10 Bibliography ............................................... 247
Curriculum Vitae .............................................. 260
|
|
