gps--Remote Sensing of Ocean, Land and Ice Surfaces Using

fei_yang

Table of Contents

1  Introduction............................................................................................................................. 1
1.1  Satellite Remote Sensing ................................................................................................ 1
1.2  Remote Sensing Using Bistatically Reflected GNSS Signals ........................................ 2
1.3  Selecting a Focus ............................................................................................................ 3
1.4  Motivation....................................................................................................................... 4
1.4.1  Remote Sensing of Ocean Winds and Roughness .................................................................................5
1.4.2  Remote Sensing of Sea Ice.....................................................................................................................7
1.4.3  Remote Sensing of Land Surfaces .........................................................................................................8
1.5  Organization of Dissertation........................................................................................... 9
2  Foundations of the GNSS Bistatic System ........................................................................... 12
2.1  Global Navigation Satellite Systems ............................................................................ 12
2.2  GNSS Bistatic Geometry .............................................................................................. 13
2.3  Delay and Doppler Spreading of a GNSS Reflection Over the Surface....................... 14
2.4  Electromagnetic Scattering Model................................................................................ 16
2.5  Representing the Sea Surface........................................................................................ 19
2.6  Doppler Spreading Over the Surface ............................................................................ 23
2.7  Expected Delay Waveforms and Delay-Doppler Maps................................................ 24
2.7.1  Delay Waveforms ................................................................................................................................25
2.7.2  Delay Doppler Maps ............................................................................................................................27
2.8  GNSS Ocean Remote Sensing: Using Comparisons to Model Waveforms ................. 29
2.9  GNSS Ocean Remote Sensing: Empirical Inversion Functions ................................... 30
3  Experimental Basis of this Research..................................................................................... 33
3.1  The UK-DMC Satellite GNSS Bistatic Radar Experiment .......................................... 33
3.2  Operations and Data Collections .................................................................................. 35
3.3  Antenna Configuration.................................................................................................. 40
3.4  Independent Validation Sources ................................................................................... 41
3.4.1  Satellite Orbits: Space Track................................................................................................................41
3.4.2  GPS Constellation: International GPS Service ....................................................................................42
3.4.3  Ocean Validation: NDBC Buoys .........................................................................................................42
3.4.4  Ocean Validation: QuikSCAT .............................................................................................................43
3.4.5  Ocean Validation: ECMWF Weather Model .......................................................................................43
3.4.6  Ice Validation: National Ice Centre (U.S.) ...........................................................................................44
3.4.7  Land Validation: Weather Underground..............................................................................................44
3.4.8  Land Validation: USGS Photographs ..................................................................................................45
3.4.9  Land Validation: Google Earth ............................................................................................................45
4  Processing and Detection of Ocean Reflected Signals ......................................................... 46
4.1  Overview....................................................................................................................... 46
4.2  Signal Processing Overview: Signal Search Process.................................................... 47
4.3  Signal Processing Overview: Averaging of a Power Detected Signal ......................... 49
4.3.1  Example Signals After Averaging .......................................................................................................51
4.4  Signal Processing Overview: Coherent Integration Time ............................................ 53
4.5  Delay Waveforms: Two Parallel Reflections ............................................................... 56
4.6  Delay-Doppler Maps Under Different Ocean Conditions ............................................ 58
  vii
5  Ocean Sensing Using Theoretical Models ............................................................................ 61
5.1  Overview....................................................................................................................... 61
5.2  Fitting Model Delay Waveforms to Detected Signals .................................................. 61
5.3  Sensing Wind and Waves Over Short Averaging Intervals.......................................... 63
5.4  Fitting Model Delay Waveforms Under Rough Conditions. ........................................ 65
5.5  Model Fitting Using a Long Averaging Interval. ......................................................... 66
5.6  Conclusions................................................................................................................... 69
6  Calculation of the Bistatic Radar Cross Section ................................................................... 71
6.1  Overview....................................................................................................................... 71
6.2  Expression for Received Signal Power......................................................................... 72
6.3  Expression for the Signal to Noise Ratio...................................................................... 75
6.4  Selecting the Surface Area for Calculating the BRCS.................................................. 78
6.5  Final Expression for the BRCS..................................................................................... 80
6.6  Example Signals Under Different Ocean Conditions ................................................... 81
6.7  Measuring the Processed Signal to Noise Ratio ........................................................... 83
6.8  Measuring the Absolute Signal to Noise Ratio............................................................. 85
6.9  Measurements of the BRCS.......................................................................................... 87
6.10  Consistency of BRCS Measurements Across a Single Data Set .................................. 88
7  Empirically Based Ocean Sensing........................................................................................ 92
7.1  Overview....................................................................................................................... 92
7.2  Summary of Data Sets Used and In-Situ Measurements .............................................. 92
7.3  BRCS Calculations ....................................................................................................... 95
7.4  Measurements Across Data Sets Under Similar Ocean Conditions ............................. 98
7.5  The Effects of Wind-Wave Divergence and Swell ..................................................... 101
7.6  Relationship Between the BRCS and Near Surface Wind Speed............................... 103
7.7  Relationship Between the BRCS and Ocean Waves .................................................. 105
7.8  Relationship Between Doppler Frequency Spreading and Ocean Waves .................. 107
7.9  Conclusions................................................................................................................. 109
8  Analysis of Error Sources and Measurement Accuracy ..................................................... 110
8.1  Overview..................................................................................................................... 110
8.2  Errors Due to Geometry and Surface Wave Direction ............................................... 111
8.3  System Errors.............................................................................................................. 113
8.4  A Statistical Examination of Fading Noise................................................................. 115
8.5  Signal Statistics as a Function of Delay...................................................................... 122
8.6  Signal Statistics Dependence on Antenna Gain and Incident Angle .......................... 128
8.7  Accuracy of Wind and Wave Retrievals..................................................................... 133
9  Ice Sensing.......................................................................................................................... 136
9.1  Overview..................................................................................................................... 136
9.2  UK-DMC Data Collections Over Sea Ice................................................................... 137
9.3  In-Situ Sea Ice Validation Sources ............................................................................. 139
9.4  Criteria For a Coherent Surface Reflection ................................................................ 140
9.5  Predicting the C/A Code Phases and Doppler Frequency .......................................... 141
  viii
9.6  Phase Information in the Ice Reflected Signal............................................................ 143
9.7  Sensing Sea Ice Concentration.................................................................................... 146
9.8  Conclusions................................................................................................................. 148
10  Land Sensing................................................................................................................... 149
10.1  Overview..................................................................................................................... 149
10.2  UK-DMC Data Collections Over Land ...................................................................... 149
10.3  Knowledge of Terrain and Surface Conditions During Data Collections .................. 150
th
10.3.1  May 25  2005, North America ..........................................................................................................150
th
10.3.2  December 7  2005, North America ...................................................................................................152
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10.3.3  January 5  2006, Western Australia ..................................................................................................155
10.4  Variations in the Signal Magnitude ............................................................................ 157
10.5  Discussion on Received Signals Response to Surface Features ................................. 159
10.6  Delay Doppler Maps of Land Scattered Signals......................................................... 160
10.7  Conclusions................................................................................................................. 162
11  Constellation Design to Provide Dangerous Sea Warnings............................................ 163
11.1  Overview..................................................................................................................... 163
11.2  Mission Requirements ................................................................................................ 164
11.3  Possible Satellite Platforms......................................................................................... 165
11.4  Coverage Analysis ...................................................................................................... 166
11.4.1  Coverage Example: South African Straight .......................................................................................166
11.4.2  Coverage Example: Indonesia............................................................................................................171
11.5  How to Determine a Dangerous Sea........................................................................... 173
11.6  Distribution to Marine Users ...................................................................................... 174
11.7  Summary of Mission Design ...................................................................................... 175
12  Summary and Future Work............................................................................................. 177
12.1  Summary..................................................................................................................... 177
12.2  Future Work ................................................................................................................ 178
12.2.1  Ocean Sensing....................................................................................................................................179
12.2.2  Sea Ice Sensing ..................................................................................................................................180
12.2.3  Land Sensing......................................................................................................................................181
13  Bibliography ................................................................................................................... 182
1  Appendix 1 ?Signal Processing ......................................................................................... 189
1.1  Overview..................................................................................................................... 189
1.2  Signal Structure........................................................................................................... 189
1.3  Sampling the Continuous Domain Signal ................................................................... 195
1.4  GPS Coarse Acquisition Code Sequence.................................................................... 197
1.5  C/A Code Frequency Spectrum.................................................................................. 197
1.6  Locally Generated C/A Code Replica......................................................................... 199
1.7  The Correlation of the Received and Replica Signals ................................................ 200
1.8  Signal Power Expression ............................................................................................ 204
1.9  Averaging the Received Signals ................................................................................. 204
1.10  Practical Implementation ............................................................................................ 207
  ix
2  Appendix 2 - CD Information............................................................................................. 210
2.1  Data and Utilities Included on CD.............................................................................. 210
2.2  Description of Software Receiver Script File ............................................................. 211
2.3  MATLAB Functions ................................................................................................... 212
2.4  Running the Software Receiver .................................................................................. 212
2.5  Formats of GPS Telemetry File, IGS Data File and PPS Data File............................ 213

yxy7968

very good book, i like it

smrecnik

小狗快乐00

感谢楼主

udine

回复 1# fei_yang


   so expensive

udine

回复 1# fei_yang


   very good

huatiantian

感谢lz分享

pinguo227

这个不错！

thaiqi

顶~~~