Research Of Mini-SAR Real-time Imaging Based On FPGA

Synthetic Aperture Radar(SAR) imaging radar technology is a very important application. And as a moving vehicle with UAVs, high-resolution micro-SAR real-time imaging technology has increasingly become a hot topic. Compared with the traditional airborne radar, UAV miniature SAR radar imaging system size, weight, power consumption has demanding requirements. This paper discusses a single FPGA-based radar imaging system.This paper firstly introduces the development situation and the application of synthetic aperture radar real-time processing technology, the imaging system based on FPGA is introduced.Subsequently, the paper synthetic aperture radar imaging principle is analyzed and the main processing chip selection. The paper identified the imaging algorithm, using range-Doppler algorithm. System design, chip select Z7 series chips. Zynq-7000 Series is the first on a single chip also integrates a dual-core ARM and FPGA chip. The main advantage of ARM processor is that can efficiently process control system. While for high-precision complex algorithms(such as motion estimation, Doppler centroid estimation) can also be handled by the ARM processor. The chip integrates an FPGA can complete the main algorithm flow imaging, to achieve real-time imaging.Data preprocessing is an important part of real-time imaging. The digital down conversion of digital signals into IF direct acquisition baseband signal. By digital down-conversion processing of the data after the decimation filtering, decimation filtering in the undistorted distance from the signal while reducing the amount of data, saving resources. Azimuth Azimuth prefilter guarantee undistorted signal while reducing the amount of data increases processing time interval. Azimuth data pre-filter in front of 10 KHz, but after bearing pre-filtering, frequency of heavy data 500 Hz. Completed a one-dimensional distance pulse to pulse compression processing distance.Imaging algorithm processing is performed after the data preprocessing, including a compensation range migration correction and azimuth compression. A compensation range migration correction makes clearer image, higher resolution. In order to save resources, more efficient imaging processing, we propose the idea module reuse. According to a compensation range migration correction, the structural characteristics of pulse position, the three modules with a module reuse processing, high resource utilization. Finally, to test the system, a SAR image azimuth data bit 8192, and the data re frequency of 500 Hz, the request must be completed in the 16 s processing a picture of, in this system, 10 s to complete image processing, so reach the requirements of real-time imaging, to complete the task index.Finally, this article summarizes the work and outlook. This paper discusses the methods used to achieve higher image resolution.