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Studying of Fading Statistics in a RADAR Imaging System
Maryam Dehghani
Remote Sensing Group
Geological Survey of Iran,
Iran
Email: Dehghani_rsgsi@yahoo.com
Over the past two decades, the microwave remote sensing has evolved into an important tool for different geosciences applications. In this system, at first, radar transmits pulse toward a target, while it receives the its backscatter in the next stage. The total electric field of a ground pixel that the radar system receives is the summation of all individual electric field related to different points in a pixel. This summation varies from time to time or point to point because the radar system is moving during data acquisition. The fluctuation of the received voltage is called fading. Fading effect is responsible to produce the speckle noise in the radar image. The possible distribution functions of the fading signals are exponential as well as Rayleigh. However, the range of fading associated with these distributions is so large. The larger range of fading causes the less interpretability of the image. As a result, there is a little chance of finding a value from these distributed ensemble close to the mean. Clearly, averaging of a number of independent samples is an absolutely necessity to determine the mean voltage. One should notice that in averaging process the number of independent samples in a pixel. This paper focuses on the studying of fading statistics before and after the averaging process. Moreover, the relationship between the interpretability of radar image and image resolution is studied, quantitatively.
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