第四章雷达新技术(1)

4. 雷达新技术 4.1.1极化雷达和极化干涉雷达：电磁理论基础-极化定义
2 2 | E | | E | y S0 x Q | Ex |2 | E y |2 ˆ, y ˆ) (x U 2 Re Ex E y V E E 2 Im x y 2 2 | E | | E | b S0 a Q | Ea |2 | Eb |2 ˆ) ˆ, b (a U 2 Re Ea Eb V E E 2 Im a b 2 2 | E | | E | l r S0 Q | El |2 | Er |2 ˆ ˆ) (l , r R El Er U 2 Re V 2 Im E E l r
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Figure 1-4: 线极化
Figure 1-5: 椭圆极化
Figure 1-6: 园极化
4. 雷达新技术 4.1.1极化雷达和极化干涉雷达：电磁理论基础-极化定义
•Whiz Quiz Question: Why are the horizontal and vertical components sufficient to describe the polarization of an EM wave? Answer: The A Th polarization l i ti of f a plane l EM wave is i described d ib d by b the locus of its Electric Field vector in a plane perpendicular to the direction of propagation. Two orthogonal components are required to describe the location of the vector in the plane, and horizontal and
4. 雷达新技术 4.1.1极化雷达和极化干涉雷达：电磁理论基础-极化定义
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4. 雷达新技术 4.1.1极化雷达和极化干涉雷达：电磁理论基础-极化定义
The p polarization state of a p plane wave can be described by y orientation and ellipticity, plus a parameter S0 that is proportional to the total intensity of the wave. Writing the horizontal and vertical components of the Electric Field vector as Eh and Ev, the British physicist, Gabriel Stokes, described the polarization state of the EM wave by a 4-element vector, [ S0, Q, U V ] T, now known as the Stokes vector:
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Figure 1-1 极化电磁波的传播
Figure 1-2: Polarization ellipse showing h i the th orientation i t ti angle l and d ellipticity, which are a function of the semi-major and semiminor axes, a and b
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(1) ( )
The British physicist, George Gabriel Stokes, was ust 13, 1819 in Skreen, County Sligo, Ireland, and became a professor at Cambridge in 1849, a position he held until his death on February 1, 1903 (the centennial is soon). In addition to his work with polarimetry and the theory of light, he is also known for hi research his h in i fluid fl id mechanics, h i spectrum t analysis, l i geodesy, d and d the th theory th of f sound d and d vector t calculus. l l He was elected as a member of the Royal Society in 1851, and was its president from 1885 to 1890. He was also a member of the British Parliament from 1887 to 1892, noted for supporting educational issues. born on Aug
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4. 雷达新技术 4.1.1极化雷达和极化干涉雷达：电磁理论基础-极化定义
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Figure 1-3: The shape of the polarization ellipse as the relative phase between the horizontal and vertical components of the Electric Field vector is varied from 0 to 15 /8 radians in steps of /8
世界上主要的极化SAR系统: 机载系统
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世界上主要的极化SAR系统: 机载系统
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世界上主要的极化SAR系统: 机载系统
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世界上主要的极化SAR系统: 机载系统
Developed by Canada Centre for R Remote t Sensing S i CCRS –1974 Fully Polarimetric SAR at C-Band Now owned and operated by Environment C d Canada Viewed as a primary research tool to support CCRS work for RADARSAT 2 and ENVISAT
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世界上主要的极化SAR系统: 载系统
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世界上主要的极化SAR系统: 机载系统
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世界上主要的极化SAR系统: 机载系统
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世界上主要的极化SAR系统: 机载系统
世界上主要的极化SAR系统: 机载系统
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世界上主要的极化SAR系统: 机载系统
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世界上主要的极化SAR系统: 机载系统
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2 2 2 | E | | E | v h S S 0 0 2 2 Q | Ev | | Eh | S cos 2 cos 2 0 R Ev Eh S0 sin 2 cos 2 U 2 Re S sin 2 V 2 Im Ev Eh 0
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水平极化和 垂直极化
Stokes 矢量可 以由不 同极化 基组成
任意正交的 线极化
左旋圆极化 和右旋圆极 化
4. 雷达新技术 4.1.1极化雷达和极化干涉雷达：电磁理论基础-极化定义
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An electromagnetic plane wave can be completely polarized, partially polarized or completely unpolarized. In the completely polarized case, only 3 of the Stokes parameters are independent, because of the total power relation:
第 9 次课主要内容： 第四章 雷达新技术 4.1 极化雷达和极化干涉雷达 4 1 1基本原理：极化散射信息 4.1.1 基本原理 极化散射信息 4.1.2关键技术：天线、接收机、数据采集 4.1.3主要应用：目标分类和识别
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第四章 雷达新技术 4 1 极化雷达和极化干涉雷达 4.1
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世界上主要的极化SAR系统: 机载系统
世界上主要的极化SAR系统: 星载系统
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4. 雷达新技术 4.1.1极化雷达和极化干涉雷达：电磁理论基础-极化定义
Figure 1 1-1 1 Illustrating the propagation of an electromagnetic plane wave. wave The Electric Field vector has horizontal (green) and vertical (blue) components, which combine yield the net Electric Field vector (red). The locus of the tip of the Electric Field vector is shown in brown, brown tracing one cycle of the waveform on a plane perpendicular to the propagation direction.
S02 Q 2 U 2 V 2
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For a completely polarized wave, the polarization state can be described by a point on the Poincaré sphere, p as shown in Figure g 1-8. The radius of the sphere p is S0, the intensity of the wave. The latitude of a point on the sphere corresponds to 2, i.e. two times the ellipticity of the wave. The longitude of a point on the sphere corresponds to 2, i.e. two times the orientation of the wave.