1、Unit 31 Interferometric SAR (In SAR) Introduction 干涉雷达(SAR)介绍Radar interferometry is a technique for extracting three-dimensional information of the Earth’s surface by using the phase content of radar signal as an additional information source derived from the
2、complex radar data. It was first used in observation of the surface of Venus and the Moon. 雷达干涉测量技术中提取三维信息的地球表面的利用雷达信号的相位内容作为额外的信息源来自复杂的雷达数据。它最初是用于观察金星和月亮的表面Graham was the first to introduce Synthetic Aperture Radar (SAR) for topographic mapping in 1974. There a
3、re two kinds of information which are required for the production of topographic maps. Firstly, the various objects and features to be mapped must be presented in an image with sufficient resolution to be identified. Secondly, a three_dimensional measurement of
4、position, with respect to the platform, of a sufficient number of points must be made to define the terrain surface . The three_dimensional measurement can be made by SAR interferometry with a side_looking geometry from both airborne and spaceborne SAR sensors.
5、格雷厄姆是第一个介绍合成孔径雷达(SAR)在1974年地形映射。有两种类型的信息所需的地形图的生产。首先,各种对象和特征映射必须以足够的分辨率的图像。其次,一个三维位置测量,对平台,足够数量的点必须定义地形表面。三维测量可以通过侧视SAR干涉测量几何机载和星载SAR传感器。A Synthetic Aperture Radar is an active sensor transmitting and receiving microwave signals, i .e . Measuring distances betwe
6、en the sensor and the point on the Earth’s surface, where the signal is backscattered. The sensor emits electromagnetic radiation (EMR) and then records the strength and time delay of the returning signal to produce images of the ground. The EMR involved can be
7、imagined as a sine wave. Conventional SAR images are made up (as a raster) of the amplitude or ‘strength’of the sine wave — shown in images as grey level intensity values .When the sine wave starts to repeat itself (phase angle > 360 degrees) , one cycle of phas
8、e has occurred . If we collect two separate images from exactly the same satellite position (same range) , but at different times with nothing in the target area chan
