第五章 干涉合成孔径雷达概念

~The End~
Thank you!
Schematic Map of InSAR for Geophysical Application
Master SAR Image（主）
Phase Differences （相位差）
Slave SAR Image（从）
Topography /deformation, etc. （地形、变形等）
InSAR Configuration（配置）
Double-slit experiment (Thomas Young, 1801)
Schematic Geometry of InSAR （InSAR成像几何）
SAR2 SAR1 SAR1 SAR2 SAR3
Surface at epoch 1 Two SAR image（二轨）
Surface at epoch 2
With very high accuracy 4
SAR1
B
SAR2

2 2 1 1
DEM : Z p f1 ( , B, ) or Deformation : r f 2 ( , B, )
InSAR geometry ( 1 2 )

InSAR - A Phase Analysis Technique (III) （相位分析技术）

InSAR

First-order differentiation of phase （一阶差分） DEM or topography reconstruction （地形重建）

DInSAR

Second-order differentiation of phase （二阶差分） Reveal a wealth of geophysical phenomena, e.g. ground subsidence （地表形变等地球物理现象）
First-order differentiation: Phase and topography （一阶差分）
Three SAR images （三轨）
Using Interferometry for Measurements（采用干涉进行测量）
SAR2 SAR1
R1 R2 Interference fringes
SAR Interferogram（干涉图）

SAR interferogram（干涉图，共轭相乘）
Understanding Interferometry （理解干涉）

The classical double-slit experiment captures the essences of modern SAR interferometry （来自经典双缝干涉实验）
R1 R2 Interference fringes

Amplitude（灰度）
A( r, t ) abs[ M ( r, t ) S ( r, t ) ]
Example of SAR Interferogram
InSAR - A Phase Analysis Technique (I) （相位分析技术）
Path difference results in phase shift （路径差导致相移）
Second-order differentiation: phase and deformation
（二阶差分）
Landers earthquake
InSAR - A Phase Analysis Technique (IV) （相位分析）
4 1 1 1 2 4 2 2
From Hanssen
First-order differentiation: Phase and topography （一阶差分）
From Hanssen
Second-order differentiation: phase and deformation （二阶差分）
From Hanssen

Along track（沿轨道） Across track（交叉轨道） Repeat pass（重复轨道）


Along Track（沿轨道）

Two SAR antennae mounted on the same platform（两根天
线安装在同一平台）

Interferometric baseline formed parallel to flight direction.
（干涉基线平行与飞行方向）

Mainly in Airborne systems （主要在机载平台使用） Mainly for the mapping of ocean currents, tidal motions and the detection of moving objects （主要用于海浪和运动目标
INTF ( r, t ) M ( r, t ) S ( r, t )

Interferometric phase（干涉相位）
( r, t ) 1 ( r, t ) 2 ( r, t )
tan 1[ M ( r, t ) S ( r, t ) ] [ , )
检测）
From Gens et al., 1996
Across Track （交叉轨道）

Two SAR antennae mounted on the same platform （两根天线安装在同一平台） Interferometric baseline formed perpendicular to flight direction. （干涉基线垂直与飞行方向） Airborne systems and spaceborne systems as well Mainly for topographic mapping （主要用于地形 测绘） Example: shuttle radar topography mission (SRTMt al., 1996
Repeat Pass （重复轨道）

A single antenna mounted on the platform （一根天线） A revisit of the same scene is needed to perform interferometry （需要重复观测） Mainly in spaceborne SAR systems Mainly for ground deformation mapping, earthquake and volcano study, etc. （主要用于监测变形） The cheapest and most popular configuration Example: Seasat, ERS-1/2, JERS-1, Radarsat, Envisat

InSAR is a class of techniques that follow from analysis of interferometric phases (i.e., phase differences of SAR images)

Range differences can be inferred from phase differences（距离差可 以从相位差计算出来） With range differences and imaging geometry condition, one can do 3D reconstruction or surface deformation measurements （通过距离差和 成像几何条件，可以重建三维或监测地表形变）
InSAR Advantages（InSAR优越性）

Work day and night, and under all-weather conditions High spatial resolution (decameters), and large spatial coverage (10000 km2) High sensitivity to deformation (mm-cm) No ground control station Low cost, high automation in data processing
Interferometric Synthetic Aperture Radar (InSAR)（干涉合成孔径雷 达概念）
InSAR
--- Synthetic aperture radar interferometry (InSAR): Conventional SAR + interferometry technique（常规SAR 技术和射电天文干涉技术的结合） --- Two or more SAR images (acquired at different positions and/or times) are generally needed（需要2景或多景SAR数 据） --- Mainly phase data in SAR images are employed to extract value-added information（主要使用其中的相位信息）
780 km
c 5.6 m
•
Phase is a function of distance from satellite to ground (range)（相位是卫 星到目标距离的函数） From Funning et al., 2005
InSAR - A Phase Analysis Technique (II) （相位分析技术）


InSAR Development（InSAR发展）