基于通用软件无线电平台的电离层高频多普勒频移监测仪  

Ionospheric high-frequency Doppler shift based on a universal software-defined radio platform

作　　者：代国峰 郝永强 刘飞[4] 张东和[1] 肖佐[1] DAI GuoFeng;HAO YongQiang;LIU Fei;ZHANG DongHe;XIAO Zuo(School of Earth and Space Sciences,Peking University,Beijing 100871,China;Planetary Environmental and Astrobiological Research Laboratory(PEARL),School of Atmospheric Sciences,Sun Yat-sen University,Zhuhai 519082,China;Key Laboratory of Tropical Atmosphere-Ocean System,Ministry of Education,Sun Yat-sen University,Zhuhai 519082,China;National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012,China)

机构地区：[1]北京大学地球与空间科学学院,北京100871 [2]中山大学大气科学学院行星宜居性研究实验室,珠海519082 [3]中山大学热带大气海洋系统科学教育部重点实验室,珠海519082 [4]中国科学院国家天文台,北京100012

出　　处：《中国科学：技术科学》2024年第3期402-410,共9页Scientia Sinica(Technologica)

基　　金：子午工程和国家自然科学基金(批准号:42374186,42074192,41574144)资助项目。

摘　　要：测量经电离层反射的无线电波频率的多普勒频移是一种经典的电离层探测技术.本文介绍了以通用软件无线电平台作为射频前端的新型设备的系统设计、数字信号处理流程及数据后处理的方法.前端输出的宽频带数字信号由计算机软件进行选频、滤波、降采样等处理,具有可随时改变接收频点及数据处理流程的灵活性,并降低系统复杂度和研发周期及成本.本文比较了由快速傅里叶变换和希尔伯特变换两种方法得到的信号多普勒频移量,在电波仅有单一频移分量时,两种方法的结果是一致的;快速傅里叶变换方法能够分辨多个频移分量,而希尔伯特方法的优点则是具有较高时间分辨率.此外,采用多站数据反演了电离层扰动传播速度,把频移得到的多普勒速度与电离层垂测仪观测的电离层虚高的变化进行了对比,验证了该设备的探测能力及数据准确性.该设备已替换升级子午工程一期原设备,并将部署于子午工程二期各观测台站.Measuring the frequency Doppler shift of the radio waves reflected by the ionosphere is a classic technique for detecting the ionospheric disturbances.This paper describes a newly developed instrument in terms of the system architecture,the digital data flow and the methods for data post-processing.The instrument uses a universal software-defined radio platform as the frontend outputting wideband digital signals.The processing procedure,including the frequency selection,low-pass filter,and downsampling,is implemented in the software running on the host computer.This architecture offers the flexibility of freely changing the receiving frequency and optimizing the data flow,and reduces the system complexity and development cost.The methods of fast Fourier transform(FFT)and Hilbert transform to retrieve the frequency Doppler shift are examined.The two methods give similar results for monochromatic variations of the ionosphere,thought the FFT method has the ability to discriminate multiple Doppler frequencies;the Hilbert transform has the advantage of high time resolution.We further validate the instrument by comparing the data with an ionosonde,and calculate the velocity of a travelling ionospheric disturbance using three observation sites.The experiments validate the capability and reliability of the new instrument,which has replaced its predecessors of the Chinese Meridian Project,and will be deployed at 12 sites of the Phase II network.

关 键 词：电离层扰动 电离层高频多普勒频移 软件无线电 子午工程 

分 类 号：P352.7[天文地球—空间物理学]