Wednesday, February 9, 2011



Radar (Radio Detection And Ranging) is one form of remote sensing with active systems. Some functionality of this active radar system include Radar Imaging System that produces radar imagery, Scatterometers, and altimeter. The basic principle of this radar is transmitting and receiving feedback signals. Short-wave energy emitted from the sensor. The energy will move toward the object. Some signals are on the object will turn around and re-captured by the radar sensor. Some of the information recorded by the reflection signal captured by the sensors is such magnitude, signal phase, the time interval between when a signal is emitted and when the signal was caught again, polarization, Doppler effect frequency.
Signal transmission and reception is usually performed by a transmitter on the same radar sensors.
Radar TypeTwo types of radar is often used RAR (Real Aperture Radar) and SAR (Synthetic Aperture Radar.) Real Aperture Radar also often called SLAR (Side Looking Airborne Radar.) The second type is actually a radar system transmitting signals in the direction that usually use the aircraft.The main differences between the RAR and SAR system is the direction azimutnya. Real Aperture Radar azimuth resolution is determined by a sweep width (beamwidth), so the resolution azimutnya proportional to the distance between the radar with its target. Synthetic Aperture Radar uses a signal processing circuit for synthesizing a few recordings that captured sensor signal reflections.Characteristics of radar imageRadar images have characteristics that are fundamentally different from the images obtained in obtis such as satellite images or aerial photographs. These characteristics are related to the techniques used in radar image capture and also the concept of radiometry. Radar images are printed into hardcopy will look very different from the images produced from satellite imagery or other human eye.Shadows on radar images related to the slope of the microwave energy emitted from the radar system, not because the sun's beam angle geometry factor. Level grayish (greyscale) in radar images related to the relative strength of the microwave dipencarbalikkan by landscape elements. Pencarbalikan signal intensity value will depend on the roughness of diverse landscapes and land slope. Radar signal is mainly related to the geometric condition that the target area.The parameters used in the analysis of radar imagery is color, texture, shape, structure, and size.ColorRona on radar images is the average intensity of the signal terpencarbalikkan. High signal will appear with a bright hue, while the low signal will be raised with a dark hue.TextureTexture in radar images related to the spatial distribution of the resolution cell. There are three classes of this radar image texture on the texture of micro, meso textures and macro textures.FormForms can be defined as a form of spatial contours associated with a relatively constant or the limits of a simple object. Some objects such as roads, bridges, aircraft runway, and others can be recognized from its shape.StructureStructure is the spatial arrangement of objects covering the entire region with a repetitive configuration.SizeThe size of this object is used as a qualitative element identification on radar images. The size of the recognized object in the image gives the relative understanding of the scale and various dimensions of other objects.

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