基于FPGA的SAR原始数据实时压缩系统设计与实现

文章讨论一种基于FPGA,并采用分块自适应量化(BAQ)算法的SAR原始数据实时压缩处理系统的设计方法,该设计可大大提高实时压缩处理系统的性能,降低数据率,突破卫星下传数据率的限制。BAQ模块内部采用4路并行处理的逻辑结构来计算数据块的统计特性;优化设计量化电平实时计算乘法器资源、量化比较逻辑结构;当I/Q两路采用多模块分时复用模型时,可使整个系统压缩处理能力成倍增加。通过测试表明,BAQ模块的最高运行速度可达到149 MHz,单个模块处理能力已达到1 Gbps以上,其中压缩比8/3时信号失真噪声比(SDNR)大于14 dB。

Design and implementation of the SAR raw data real-time compression system based on FPGA

The SAR raw data rate is an important factor in the design of spaceborne SAR systems.In this paper,a design method of the SAR raw data real-time compression system is presented which is based on FPGA and adopts the block adaptive quantization(BAQ) algorithm.By using less hardware logic resource,the SAR raw data rate is decreased,and performance of the real-time compression system is enhanced greatly,thus the limitation of the satellite data transfer rate is overcome.In the BAQ module,four-route parallel processing logic architecture is used to deal with the statistic characteristics of data blocks;the logic architecture of multipliers and comparers is optimized,in which quantization level real-time computation and quantization comparison are carried out;and when the time-division multiple BAQ module mode is used in both I and Q channels,the real-time processing ability of the whole compression system is enhanced geminately.Experiment indicates that the highest processing speed of the BAQ module is 149 MHz,that the data throughput of single module is great than 1 Gbps,and that when the compression ratio is 8/3,the signal distortion noise ratio(SDNR) is great than 14 dB.