| Synthetic Aperture Radar(SAR) imaging has been a new developing trend of radar. Based on the principle of synthetic aperture and pulse compression technology, SAR breaks through the limitation of real antenna aperture and realizes 2-D high resolution imaging of distant targets. But conventional SAR is complicated, bulky and high energy consumption, which limits wide application. So developing the new light platform that is smaller, lighter and lower power is meaningful. This article designs a new Mini-SAR digital processing system. The author’s major contributions are outlined as follows:1. This paper calculates the parameters of digital processing module in accordance with requirements of Mini-SAR system. And a new type Mini-SAR digital processing system is developed. This new system is based on a single FPGA to imaging. Besides, the system includes DA signal generator module, AD acquisition module, FLASH memory module and so on.2. This article describes the hardware design of Mini-SAR digital processing system. It includes technical index, functional description, chip selection and circuit design. Meanwhile, a specific layout method is introduced for the dimensional requirement of digital processing board, which will improve system performance. Requirements are that the length is not more than 120 mm and the width is less than 80 mm.3. The paper discusses the software design of Mini-SAR imaging system. It includes imaging, timing, DA, AD FLASH, servo and interface program. The important modules have been tested. And analysis results meet the system’s requirements.4. A new method of waveform generation is developed in DA program. Using the AXI bus between processing system and programmable logic can realize any waveform generation and compensation.5. Several primary communication modes are introduced by studying the data interaction between PS and PL. The characteristics of each mode are discussed. Especially, this paper gives a specific implementation method for AD acquisition module.6. A file system is designed to save and read images. The file system is implemented in PS using C language, which can be used to write file, read file, delete file, etc. By file system, users can directly control digital processing system to save or read image using the interface in host computer. This operation ignores underlying FLASH program so that can improve human-computer interactive capability. |
