Research And Hardware Implementation Of Airborne SAR Imaging System Key Technology

Airborne synthetic aperture radar(SAR)has all-day and all-weather operation characteristics.It has been widely used in many fields,such as natural disaster monitoring,emergency rescue,topography mapping,battlefield surveillance and so on.It has a very important significance to the development of national economy and the modernization of national defense science and technology.However,airborne SAR imaging is susceptible to interference,which can cause image defocus.So motion compensation processing is needed.With the increase of the amount of SAR image data,the processing time of motion compensation algorithm becomes longer and longer,and the advantages of hardware-based airborne SAR imaging technology and system become more and more prominent.Aiming at the above requirements,the hardware architecture of phase gradient autofocus(PGA)algorithm applied to motion compensation is designed.Compared with the software processing method based on MATLAB,the processing speed is 6.2times higher.At the same time,in order to reduce the hardware resource consumption of airborne SAR imaging system,the architecture of fast fourier transform(FFT)module was improved,and the rotation factor module was designed by combining multiple constant multiplication(MCM)with coordinate rotation digital computer(CORDIC).The data throughput per slice is 26% higher than other typical existing hardware architectures.In addition,when airborne SAR performs long-time and long-distance missions,it needs to have high-speed storage capacity of massive data.We also design SSD storage system based on the PCIe interface and NVMe protocol,which can realize the complete workflow of initialization,read,write,format,shutdown and so on.The board-level verification results show that the SSD read speed can reach about842MByte/s,and the write speed can reach about 1.28GByte/s,when PCIe link state is set to 2.0.