Study of Very Low Frequency Solar Radio Emission Detection with Space Vector Antenna
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摘要: 目前已有空间探测器对太阳的甚低频射电爆发进行的探测主要是频谱观测，且仅覆盖甚低频频段中的很小一部分，针对太阳低频射电爆发的成像观测仍然是空白。基于空间矢量天线的特性，它可以实现对空间来波信号的达波方向进行估计。利用它可以对太阳低频射电爆发（包括Ⅱ型和Ⅲ型暴）进行空间定位和一定的成像观测。本研究针对空间（甚）低频射电探测器对太阳射电爆发的探测，提出了利用三极子矢量天线对太阳爆发进行定位的算法，并基于部分空间甚低频设备的观测数据，在不同条件下对算法进行了仿真，同时针对“嫦娥4号”上的甚低频射电探测器（同样采用了三极子矢量天线），分析了其探测太阳低频射电爆发的能力。结果表明：当信号的信噪比达到10 dB以上时，矢量天线可以实现度量级的定位精度；并进一步分析了空间低频探测器探测太阳低频射电爆发的能力。Abstract: Solar winds, coronal mass ejections（CME）, interplanetary shock waves and high-energy particle events, induced by the solar radio bursts, are called as solar electromagnetic storms. The propagation, acceleration, and evolution of the CMEs, solar winds, interplanetary shock waves and high-energy particle phenomena mainly happen at the frequency range from tens of KHz to tens of MHz, which is generally considered as the frequency band of very low frequency（VLF）. Though, there are already few space instruments that have investigated the VLF solar radio emissions, most of the observations are spectral measurements, and only occupied part of the whole VLF band, while the imaging observations of the VLF solar radio bursts are still blank. Based on the characteristics of the vector antenna, it can estimate the direction of arrival（DOA）of the incoming waves, which can be used to locate and image the solar radio bursts（Type Ⅱ&Ⅲ）. So all the latest space VLF radio instruments adopt the tripole antenna can do the observations. In this paper, in order to investigate the detection of the solar radio bursts with the space VLF radio explorer, different algorithms are proposed to detect the solar radio bursts with a tripole vector antenna, and simulations have been done with some space VLF radio observations for these algorithms under different conditions. The simulation results show that the vector antenna can locate the radio bursts with a degree-level accuracy. The capability of detecting the solar radio bursts is also analyzed in further for the space VLF radio explorer.
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Key words:
- very low frequency /
- space explorer /
- solar radio burst /
- vector antenna
Highlights● Using the characteristic of Tripole vector antenna，how to locate the solar VLF radio burst with single tripole antenna is studied. ● The DOA estimation algorithm is proposed for the tripole antenna，and simulations under different conditions show that it can locate the solar radio burst with a degree-level accuracy under certain SNR. ● The capability of detecting solar radio burst is studied for the VLF radio instrument onboard Chane’e-4 mission. -
图 1 Tripole天线对电场所扫偏振椭圆进行3D采样示意图
Fig. 1 A radio wave sensed by a tripole antenna propagates with a wave vector k sweeping out the polarization ellipse
图 4 STEREO/WAVES观测到的太阳III型射电爆发事件（20190208）
Fig. 4 Solar type III radio burst observed by STEREO/WAVES on Feb.8，2019
图 5 STEREO/WAVES观测到的太阳III型射电爆发频谱
Fig. 5 Dynamic spectrum of a solar type III radio burst observed by STEREO/WAVES
图 6 月面不同信噪比下的太阳射电爆发在20 MHz时达波方向估计
Fig. 6 DOA estimation results of the solar radio burst at 20 MHz on the Moon surface
图 7 不同频率太阳射电爆发的达波方向估计
Fig. 7 DOA estimation results of solar radio burst for different frequencies
图 9 单极子组合成偶极子的共模抑制频谱
Fig. 9 Common-mode RFI rejections by combining two monopoles to get dipole antenna
表 1 不同信噪比下的DOA估计误差
Table 1 DOA estimation errors for different SNR
DOA估计误差/dB DOA 方位角 /（°） 俯仰角 /（°） 信噪比 5 4.189 9 2.835 6 10 1.812 8 1.421 3 20 0.651 9 0.632 1 30 0.347 8 0.262 7 
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表 2 不同频率的DOA估计误差
Table 2 DOA estimation errors for different frequencies
DOA估计误差/MHz DOA 方位角 /（°） 俯仰角 /（°） 频率 10 1.488 2 0.972 6 20 1.212 2 0.716 7 30 1.053 2 0.712 0 40 1.417 8 0.783 2
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[1] 陈林杰. 月基甚低频射电干涉仪技术研究[D]. 北京: 中国科学院大学, 2011. [2] 纪奕才,赵博,方广有,等. 在月球背面进行低频射电天文观测的关键技术研究[J]. 深空探测学报,2017,4(2):150-157.JI Y C,ZHAO B,FANG G Y,et al. Key Technologies of very low frequency radio observations on the lunar far-side[J]. Journal of Deep Space Exploration,2017,4(2):150-157. [3] 张锦绣,陈学雷,曹喜滨,等. 月球轨道编队超长波天文观测微卫星任务[J]. 深空探测学报,2017,4(2):158-165.CAO X B,ZHANG J X,CHEN X L,et al. Formation flying around lunar for ultra-long wave radio interferometer mission[J]. Journal of Deep Space Exploration,2017,4(2):158-165. [4] SARKAR T K,PEREIRA O. Using matrix pencil method to estimatethe parameters of a sum of complex exponentials[J]. IEEE Antennas Propag. Mag.,1994,37(1):48-54. [5] HAARDT M,NOSSEK J A. Unitary ESPRIT:how to obtain increased estimation accuracy with a reduced computational burden[J]. IEEE Trans. Signal Processing,1995,43(5):1232-1242. doi: 10.1109/78.382406 [6] YILMAZER N,KOH J. Utilization of a unitary transform for efficient computation in the matrix pencil method to find the direction of arrival[J]. IEEE Transactions on Antennas and Propagation,2006,54(1):171-181. [7] CAROZZI T,KARLSSON R,BERGMAN J. Parameters characterizing electro-magnetic wave polarization[J]. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics,2000,61(2):2024-2028. [8] DALDORFF L K S. TURAGA D S, VERSCHEURE O, et al. Direction of arrival estimation using single tripole radio antenna[C]//Proceedings of the 2009 IEEE ICASSP. [S.l.]: IEEE, 2009. [9] CHEN L, AMINAEI A, FALCKE H, et al. Optimized estimation of the direction of arrival with single tripole antenna[C]//2010 Loughborough Antennas & Propagation Conference. [S.l.]: IEEE, 2010. -
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