Airborne Synthetic Aperture Radar Azimuth Preprocessing Using Programmable Logic Devices, Design And Implementation

This thesis focuses on the azimuth preprocessor in the imaging processor on the basis of the project "A real-time digital imaging processor of air-borne SAR (Synthesis Aperture Radar) system"of IEAS (The Institute of Electronics, Chinese Academy of Sciences). New azimuth preprocess method of band-pass filtering subaperture is proposed. Hardware of azimuth preprocessor is designed and realized with CPLD chip.The computation amount is large in the real-time digital imaging processor of air-borne SAR. The parallel process structure can be realized by sub-aperture method in system to improve its signal process ability, which is analyzed and discussed detailedly in thesis.But the sub-aperture method can cause many complexes in azimuth preprocess. We analyze detailedly the azimuth preprocess principle and propose the band-pass filtering sub-aperture method, which can simplify the process effectively.System performance can be improved by the application of PLD (Programmable Logic Device), which mostly was used in simple circuit control in SAR signal processing field formerly, rarely in complex algorithmic process realization. Along with the development of integrated circuit, PLD has been good enough for realizing complex system now. We explore this point, and design the azimuth preprocessor with the CPLD (Complex Programmable Logic Device) chip of EPFIOK5OVQC24O-3, which is module structured and linear pipeline processed. The application of this design in the real-time imaging processor results in the system performance improvement in many aspects such as the physical structure, run-time efficiency, power consumption and system cost.The azimuth preprocessor design with CPLD is the first time in realizing complex algorithm with PLD in IEAS. Its success marks our progress in hardware design technique. It not only improves the performance of the existing real-time imaging process system, but also brings us with valuable application experience and new design way in complex signal processing field for SAR system in future.