电子学报 ›› 2022, Vol. 50 ›› Issue (6): 1472-1479.DOI: 10.12263/DZXB.20201178

• 学术论文 • 上一篇    下一篇

高光谱微波辐射计系统中2GHz带宽数字谱仪设计

许皓文1,2, 陆浩1, 王振占1   

  1. 1.中国科学院国家空间科学中心微波遥感技术重点实验室,北京 100190
    2.中国科学院大学,北京 100049
  • 收稿日期:2020-10-22 修回日期:2021-03-23 出版日期:2022-06-25
    • 通讯作者:
    • 陆浩
    • 作者简介:
    • 许皓文 男,1995年生,河南许昌人.2016年于郑州大学获得工学学士学位.现为中国科学院国家空间科学中心博士研究生.主要研究方向为微波遥感定标、高速数字谱仪的理论与应用等.E-mail: xuhaowen1223@163.com
      陆 浩(通讯作者) 男,1988年生,安徽亳州人.2012年于中国科学院研究生院获得工学博士学位.现为中国科学院国家空间科学中心副研究员.主要研究方向为大规模数字电路、微波辐射计系统研制和定标等. E-mail: luhao0408@126.com
      王振占 男,1969年生,河北秦皇岛人.2005年于中国科学院研究生院获得理学博士学位.现为中国科学院国家空间科学中心研究员.博士生导师.主要研究方向为微波遥感定标、定量反演与应用技术.E-mail: wangzhenzhan@mirslab.cn
    • 基金资助:
    • 中国科学院国家空间科学中心五个重点培育方向“极端天气与全球变化卫星遥感观测研究”项目 (Y92112A)

Design of 2 GHz Bandwidth Digital Spectrometer in Hyperspectral Microwave Radiometer System

XU Hao-wen1,2, LU Hao1, WANG Zhen-zhan1   

  1. 1.Key Laboratory of Microwave Remote Sensing, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China
    2.University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-10-22 Revised:2021-03-23 Online:2022-06-25 Published:2022-06-25
    • Corresponding author:
    • LU Hao
    • Supported by:
    • Key Cultivation Directions” of National Space Science Center, CAS - Study on Satellite Remote Sensing Observation of Extreme Weather and Global Change (Y92112A)

摘要:

高光谱微波辐射计是一种用于探测大气痕量气体的新型被动微波遥感器,数字谱仪是高光谱微波辐射计的核心部件.本文提出了一种新型宽带、实时数字谱仪的设计和实现方案,通过改进、结合快速傅里叶变换(Fast Fourier Transform,FFT)的并行处理和复数处理,形成了核心的基16实时复数FFT算法,最终得到信号的功率谱结果.数字谱仪采样率4.8 GHz,采用8 bit量化,输入3 dB带宽2 GHz,实现了1 024(1k)个频谱通道的结果.本文利用大气辐射传输模拟器(Atmospheric Radiative Transfer Simulator,ARTS)模拟了真实大气亮温谱并进行了仿真分析,随后通过输入的点频信号进行了测试,结果表明,核心算法子带亮温偏差最大值为0.02 K左右,核心算法子带灵敏度与理想子带灵敏度相比恶化程度低于20%,数字谱仪的有效位数(Effective Number Of Bits,ENOB)优于3 bit,信噪比(Signal to Noise Ratio,SNR)优于20 dB,谱分辨率恒定为2.3 MHz,可以有效满足辐射计中高层大气谱线探测的需求.

关键词: 微波临边探测, 高光谱微波辐射计, 宽带数字谱仪, FPGA并行处理, 基16实时复数FFT算法

Abstract:

Hyperspectral microwave radiometer is a new type of passive microwave remote sensor for detecting atmospheric trace gases, and the digital spectrometer is the core component of the hyperspectral microwave radiometer. In this paper, a new broadband, real-time digital spectrometer design and implementation scheme is proposed. The core radix 16 real-time complex fast Fourier transform(FFT) algorithm is formed by improving and combining the parallel processing and complex processing of FFT. Finally, the power spectrum of the signals can be obtained. The results for 1 024(1k) spectral channels are achieved by the digital spectrometer with the sampling rate of 4.8 GHz, the quantization bits of 8 bit, and the input 3 dB bandwidth of 2 GHz. The real atmospheric brightness temperature spectrum is simulated and analyzed by atmospheric radiative transfer simulator(ARTS), and then the input point frequency signal is tested. The results show that the maximum value of sub-band brightness temperature bias caused by the core algorithm is about 0.02 K, and the core algorithm sub-band sensitivity deteriorates within 20% compared with the ideal sub-band sensitivity. The effective number of bits(ENOB) of the digital spectrometer is better than 3 bit, the signal-to-noise ratio(SNR) is better than 20 dB, and the spectral resolution is constant at 2.3 MHz, which can effectively meet the requirements of radiometers for spectral line detection in middle and upper atmosphere.

Key words: microwave limb sounding, hyperspectral microwave radiometer, broadband digital spectrometer, FPGA parallel processing, radix 16 real-time complex FFT algorithm

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