全极化辐射计的2GHz带宽数字相关系统设计

Design of 2GHz bandwidth digital correlator in fully polarimetric radiometer

全极化微波辐射计是进行海面风场测量的新型被动式遥感器。数字极化辐射计通过数字相关器对两个极化通道做相关处理,完成四个Stokes矢量参数的测量,反演海面风场。文中提出辐射计核心器件宽带数字相关器的设计方法。双极化通道通过IQ变换转化为两对正交信号,四片国内自主研制的A/D转换器以2.2Ghz采样率采样四路信号,采样结果通过多路复用DEMUX芯片复用后,传输到新一代现场可编程门阵列(FPGA)-Virtex5芯片中作进一步多路复用和相关运算。文中详细介绍了系统结构,数据处理流程和测试结果。

Fully polarimetric microwave radiometer is a new type of passive sensors for sea surface wind measure. Four Stokes parameters are measured to get the ocean surface field by digital correlator in digital polarization radiometer. As the core part of radiometer, broadband digital correlator is introduced in the paper. Dual-polarized channels are translated to IQ transformer to output two pairs of orthogonal signals. Four channels are sampled by four A/D converters produced in China at 2.2 Ghz rate with the sampling results translated to the newest Field-Programmable Gate Array （FPGA）-Virtex5 by multiplexer. More multiplexing and correlating operation are completed in FPGA. The structure of interfacing circuit, data processing and circuit measurement are presented in detail.