SAR Real-time Imaging System Design Based On FPGA

Synthetic aperture radar (SAR) is a kind of high-resolution imaging radar withthe all-day, all-weather, ultra-long-range characteristics. With the development ofSAR, the direction of which is multiplicity, high resolution and real-time imaging,the data received from the radar becomes larger and larger and the imaging timeturns to be even shorter. The traditional real-time imaging revolution cannot meet thereal-time demand of the radar system. From the application of SAR real-timeimaging processing technology, according to the requirement of a pre-researchproject, this article is aimed at developing a high-performance real-time imagingsystem of SAR.This paper analyzes the basic imaging principle of synthetic aperture radar.After researching distance Doppler Chirp Scaling algorithm, Chirp Scaling algorithmand wk algorithm, the CS algorithm is selected as the real-time imaging algorithm ofthe system. The system solution is determined according to the requirements of thesystem indicators. Discuss the hardware design of all parts of the system in detail,including data acquisition module, FPGA configuration circuit and interface modules.At the aspect of algorithm implement, this system uses a large capacity FPGA chip toimplement the CS algorithms. The main steps of CS algorithm include FFT, floating-point complex multiplication, transposition memory and Sinc difference. Thedifficulty of the algorithm module design lies in the FFT and transposition memory.The FFT module is achieved with base-4algorithm, using a lot of memory to achievepipeline structure. This structure can greatly improve the operation speed of the FFTmodule. Build a simulation test platform and use it to test the accuracy of FFTmodule. The transpose storage module adopted line write and line read algorithm toachieve, which can effective solve the match problem of range compression’s andazimuth compression’s read and write speeds. After the design, select a scene echo imaging data to do imaging test of the whole system.The actual imaging results show that the SAR real-time imaging system basedon FPGA can process the echo data from the radar and has a better real-time feature.