RADAR IMAGE FOCUSING PROCESS IN AZIMUTH DIRECTION USING SYNTHETIC ARRAY TECHNIQUE

• Main Authors: De-ming Chu, 朱得銘
• Other Authors: Yu-Chang Tzeng
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/10091551763402728186

碩士 === 國立聯合大學 === 電子工程學系碩士班 === 94 === The Remote Sensing Image Processing Lab cooperated with the Center for Space and Remote Sensing Research at National Central University to design a ground radar system. The aims of this system are to acquire a radar image and to make use of digital signal processing techniques to focus the image for improving image resolution. In the previous studies, which were performed in the Center of Space and Remote Sensing Research, step frequency continuous wave technique was adopted to modulate the transmitted electromagnetic waves so that Inverse Fourier Transform could be applied to the received radar echoes and image focusing in the range direction could be achieved. However, without Doppler frequency, image focusing in the azimuth direction can not be realized by making use of the conventional approach because that this system has no moving mechanism. To overcome this difficulty, this study applies synthetic array technique to transfer time domain Fourier Transform into spatial domain Fourier Transform with a virtual speed so as to attain image focusing in the azimuth direction. A computer simulation of this approach is done in this study. Then, this approach is applied to the real radar image acquired by this system as a verification. experimental result indicates that the parameters designed in the precious studies are over-sampled in the range direction and under-sampled in the azimuth direction.