2020 Vol. 40, No. 1

Display Method:
2020, 40(1): 1-4.
2020, 40(1): 5-8.
Statistical Study between Characteristic Parameters of Coronal Holes and Intensity/Time of Geomagnetic Storms
BU Xuan, LUO Bingxian, LIU Siqing, GONG Jiancun, CAO Yong, WANG Hong
2020, 40(1): 9-19. doi: 10.11728/cjss2020.01.009
Geomagnetic storm is an important subject in space weather forecasting. High speed solar wind originating from coronal holes passes through the interplanetary space about three days before reaching the Earth. It triggers geomagnetic storms which are dominant during the declining phase and the minimum year of a solar cycle. At present, geomagnetic storms forecasting mostly relies on solar wind parameters at 1AU, and geomagnetic storms are predicted in advance only by about 1 hour. In order to predict geomagnetic storms much earlier, it is necessary to establish the quantitative relationship between the characteristic parameters of coronal holes and geomagnetic storms from the point of the Sun, which is the source of high speed solar wind and geomagnetic storm. In this study, 152 coronal holes and relevant geomagnetic storms events from May 2010 to December 2016 are analyzed. Two characteristic parameters of coronal holes are extracted based on SDO/AIA images, and the geomagnetic index ap, Dst and AE during geomagnetic storms are analyzed. The statistical relationship between characteristic parameters of coronal holes and intensity/time of geomagnetic storms is established, which provides a basis for predicting geomagnetic storms in advance by 1~3 days based on solar EUV images.
Regional Ionosphere Modeling Based on BDS/GPS and Empirical Model
LIANG Chuan, FU Jielin, WANG Junyi, FAN Yurong
2020, 40(1): 20-27. doi: 10.11728/cjss2020.01.020
Based on the Ionospheric Pierce Point (IPP) data observed by the Beidou Navigation Satellite System (BDS) as well as Global Positioning System (GPS) and the historical data, a high accuracy modeling method for the Total Electron Content (TEC) of regional two dimensional ionosphere is proposed. The historical data are derived from International Reference Ionosphere (IRI) empirical model. The method can solve the low accuracy problem of short-period ionosphere modeling in the area lacking IPPs and the diverse distribution of IPPs in each period. Virtual IPP data estimated from the IRI model is uniformly inserted in the modeling area, and the dynamic weight value is assigned to the data using the constructed weight calculating formula according to the distance from the measured IPP. The spherical harmonic model parameters are calculated by the weighted least squares method. Based on the Global Ionosphere Map (GIM) released by Center for Orbit Determination in Europe (CODE), the comparison of the vertical TEC value obtained from this present method with the modeling method only using BDS/GPS IPP data shows that a significant accuracy improvement of the area lacking the measured IPP has been obtained by the method in this paper.
Characteristics Analysis of Thermospheric Density Response during the Different Intensity of Geomagnetic Storms
WANG Xin, MIAO Juan, LIU Siqing, REN Tingling
2020, 40(1): 28-41. doi: 10.11728/cjss2020.01.028
The CHAMP satellite data is used to analyze the characteristics of the thermospheric density during 12 different intensity geomagnetic storm events from 2002 to 2008, and the distribution characteristics of NRLMSISE-00 model during the corresponding magnetic storm events are studied. The results show that during large geomagnetic storms, the time delay of the peak thermospheric density from high latitude to low latitude is 2 hours, while the time delay during medium and small geomagnetic storms is about 3 to 4 hours. The distribution of thermospheric density in spring and autumn is basically symmetric between north and south, while in summer and winter the thermospheric density of summer hemisphere is greater than that in winter hemisphere. The thermospheric density in spring and autumn is greater than that in summer and winter. The thermospheric density obtained by the NRLMSISE-00 simulates well the pattern of the hemispherical distribution and seasonal distribution characteristics, but the simulation is smaller than the measurements. The peak change of Dst index can reflect the change of atmospheric density better than the peak change of ap index.
Characteristics of Planetary Wave Activity during the Stratospheric Sudden Warming in the Winter of 2009
WEI Xiaofang, HUANG Chunming
2020, 40(1): 42-51. doi: 10.11728/cjss2020.01.042
Based on MERRA reanalyzed data from December 2008 to April 2009, the major SSW event and the relevant Planetary Wave (PW) activities are investigated. Spectral analyses show that the stratosphere over Northern Hemispheric polar region is dominated by quasi-16-day PW during this SSW event. The corresponding amplitudes and phases of its four wave modes, i.e. W1, W2, E1, and E2, have been fitted by using the two-dimensional harmonic fitting method. The results show that all the modes display increasing amplitudes in varying degrees when the westerly wind weakens, and reach their peaks from 50°N to 80°N in the middle and upper stratosphere finally. Particularly, the W2 mode shows the largest increment and the strongest convergence among them, leading to the maximum westerly deceleration of background wind which is more than 4m·-1·d-1. The W2 mode of quasi-16-day PW exhibits the most important contribution to this SSW event. Furthermore, the results also demonstrates that the propagation of PWs is closely related to the movement of zero wind line. The W2 mode propagates vertically upward and shows longitudinally quasi-standing structure in mid-high latitudes, and then propagates to the pole and equator respectively. The mid-high latitudes are likely to be a source region of PWs.
Method of Establishing Reference Potential of Plasma Detector Using Isolated Conductor
LI Xiaoming, LIU Chao, GUAN Yibing, ZHANG Aibing
2020, 40(1): 52-57. doi: 10.11728/cjss2020.01.052
A technique of using an isolated conductor for establishing a probe reference potential in space plasma environment is presented. In this technique, a metal conductor is electrically isolated from spacecraft. Potential established at the metal conductor is added to probe's power module by circuit, thus a reference potential for the probe is established. This technique can be applied to spacecraft such as satellites safely and conveniently, and it can make the ground potential of probe basically equal to the potential of space plasma, avoiding the impact of spacecraft potential on the probe. This technique will be applied to the plasma in situ detector of China's space station. Through testing, it is verified that the reference potential of -210~+210V can be built by this technique, and this reference potential range meets the technical requirements of -200~+200V that space station plasma in situ detector needs.
On-orbit Geometric Calibration of Ionospheric Imager Based on Stellar
JIN Yunfei, WANG Yongmei, FU Jianguo, WANG Tianfang
2020, 40(1): 58-64. doi: 10.11728/cjss2020.01.058
The surface temperature of the three-axis stabilized Geostationary Orbit (GEO) satellite will change periodically during orbital operation. The thermal stress changes of the far-ultraviolet ionospheric imager and the satellite cause mechanical transmission, which causes the instrument pointing to deviate from the initial position as it is installed on the satellite. Stellar position in the inertial coordinate system remains constant, which can be used as the calibration source for the on-orbit geometric calibration of the ionospheric imager. An on-orbit geometric calibration model based on stellar is established. By taking images of the selected stellar, the deviation of the instrument on-orbit pointing from the initial value is obtained, and the imaging geometric accuracy of the ionospheric imager is improved. Finally, a simulation experiment is carried out to verify the feasibility of using this technique to perform on-orbit geometric calibration.
Effects of Thunderstorms Electric Field on Energy of Cosmic Rays at LHAASO
YAN Ruirui, HUANG Daihui, ZHAO Bing, AXI Kegu, ZHOU Xunxiu
2020, 40(1): 65-71. doi: 10.11728/cjss2020.01.065
The Large High Altitude Air Shower Observatory (LHAASO) is located in Daocheng, Sichuan. Featured with frequent thunderstorms in summer, it is beneficial to study the influence of atmospheric electric field on cosmic rays during thunderstorms. In this paper, Monte Carlo simulations are performed to study the effects of thunderstorms electric field on positrons and electrons at LHAASO. The energy distribution of electrons changes in the field. In low energy region, the total number of electrons and positrons increases significantly, while at high energies, it does not change obviously. In an electric field of 1700V·cm-1, above the threshold field of the Relativistic Runaway Electron Avalanche (RREA) process, the electrons with energy less than 120MeV can be accelerated. While the energy is below 60MeV, the number of electrons increases exponentially, with the increase amplitude up to about 2252%. It is consistent with the theory of RREA. In an field of 1000V·cm-1 (below the threshold of the RREA process), electrons with energy less than 70MeV can be accelerated, and its quantity significantly increases, but the amplification (about 86%) is far lower than that of the critical field of the RREA process. The results may provide important information to study the variations of cosmic ray intensity at LHAASO detection surface during thunderstorms.
Design of Combustion Science Experimental System for China Space Station
ZHANG Zhenzhong, KONG Wenjun, ZHANG Hualiang
2020, 40(1): 72-78. doi: 10.11728/cjss2020.01.072
In order to conduct the microgravity combustion experiments in China Manned Space Station, it is necessary to establish an onboard combustion science experiment system. With the experimental study of microgravity combustion, it is beneficial to expand the depth and breadth of combustion research and promote the development of combustion science. According to the functions to be realized and the requirements of combustion experiments, the design and analysis of the experimental system for combustion science rack are carried out. The combustion experiment system consists of eight subsystems, which is a comprehensive experiment system that is suitable for combustion experiments with gas, liquid and solid fuels, respectively. In consideration of the strength design requirements, after the completion of the scheme design, the finite element analysis of the system is carried out, and the mechanical environment experiment is completed with the developed structural setup. The experimental and analytical results show that the design can meet the requirements of the environment simulation experimental outline, and is reasonable and feasible for space experiments.
Flame Temperature Measurement by a Straight-type Schlieren Method
SHI Jianping, LIU Junguo, DAI Guoliang
2020, 40(1): 79-85. doi: 10.11728/cjss2020.01.079
It is critical to determinate the temperature distribution of flame for studying its structure. In this paper, the schlieren method of the straight-type, instead of the Z-type in common used, is employed for the sake of compatibility with other optical methods in future space experiments with different purposes. Moreover, the design of straight-type schlieren system is optimized by investigating the effects of light source, lens, and knife edge on the system sensitivity. Then, the schlieren images of a candle flame are recorded using the optimized schlieren system after calibration. The temperature distribution calculated from these images coincides with those measurement through thermocouples, thus the flame temperature can be obtained accurately from the straight-type schlieren system.
Influence of Exterior Materials Roughness Variation on Satellite Spectrum Reddening Effect
XU Bangwei, TANG Yijun
2020, 40(1): 86-92. doi: 10.11728/cjss2020.01.086
Remotely observed spectrometric characters of the objects in space with known exterior materials turned out to exhibits reddening effect, as compared to their corresponding laboratory spectra. The variation of the surface roughness of objects exterior materials in space environment is studied. Based on the spectral scattering characteristics of materials, orbit characteristics and observation conditions, the influence of surface roughness on reddening effect is simulated and analyzed. Some material samples are designed with different roughness by referring to the experimental data of related literatures, in order to simulate the variation in surface roughness of the materials exposed to the space environment. The spectrum scattering characteristics of the material with different surface roughness are theoretically modeled by Bidirectional Reflectance Distribution Function. The results show that the change of surface roughness affects the spectral scattering characteristics. The shape and distribution of scattering spectrum depend on the roughness and the geometric relationship between the incident and the reflection. The spectrometric characteristics in visible light band of the satellite with exterior material under different roughness conditions is simulated by summing all the contributing surface grid reflection scattering components. The results show that with the increase of the satellite surface roughness, the satellite reflection spectrum increases obviously as wavelength increases after 600nm. It shows that in the space environment, the change of the surface roughness of the exposed material is one of the reasons for causing the satellite reddening effect.
Active Compensation Method of Spacecraft Internal Magnetic Field Environment
YE Jiancheng, ZHOU Bin, ZHANG Yiteng, SUN Zheng
2020, 40(1): 93-101. doi: 10.11728/cjss2020.01.093
In order to solve the problem that spacecraft magnetic field interferes with inertial sensor in the mission of gravitational wave detection. A method of acquiring small-scale uniform magnetic field environment by measurement and active compensation in spacecraft complex magnetic environment is introduced. Magnetic source around inertial sensor and the magnetic field as well as its gradient distribution near inertial sensor can be obtained by distributed magnetic field detecting combined with spherical harmonic function and multi-magnetic dipole method. By properly setting coils, the linear compensation of magnetic field and the first order tensor can be realized. The influences of sensor number, magnetic source layout and other factors on the final compensation effect are discussed. Simulation results show that this method can reduce the magnetic field and its gradient near inertial sensor by 1~2 orders of magnitude, which can reduce residual magnetic control pressure of gravitational wave spacecraft platform and provide a magnetic field environment satisfying the requirements of gravitational wave detection.
A Simplified Path Searching and Correcting Method for the Calculation of Initial Value of Libration Periodic Orbit
XIONG Yao, YUAN Hong, YANG Xin, ZHANG Yang, GAN Qingbo
2020, 40(1): 102-108. doi: 10.11728/cjss2020.01.102
In the restricted three-body problem, the path searching and correcting method is often used to calculate the approximate initial value of planar and three-dimensional periodic orbit. In this paper, in view of the Circular Restricted Three-Body Problem (CRTBP), a simplified mode of this method is applied to calculate the approximate initial value of several ordinary kinds of periodic orbit. The results show that the approximate initial value obtained by the simplified method is not unique, and the precise initial values derived from the unique values above using differential correction method often include both Halo and DRO (Distant Retrograde Orbit) orbits. Moreover, under certain boundary initial values, Halo orbit will disappear from the results and the planar Lyapunov orbit or Vertical orbit will appears. The relationship between these initial values using in this method and the certain kinds of orbit needs further study.
In-orbit Operational Pattern Monitoring Algorithms Based on LightGBM for Hard X-ray Modulation Telescope Satellite
LI Yukui, LI Hu, HU Tai
2020, 40(1): 109-116. doi: 10.11728/cjss2020.01.109
The frequent switching of space hard X-ray sky survey and fixed-point observation schemes of HXMT (Hard X-ray Modulation Telescope) satellite requires real-time monitoring and identification for the satellite payloads in-orbit status. Manual monitoring according to the rules summarized by experts are used at present. Although the manual monitoring method is easy to execute and explicable, it consumes a lot of manpower and can not deal with the situation outside the rules flexibly. According to the real-time telemetry data of HXMT satellite, an in-orbit operation mode monitoring algorithm based on LightGBM is proposed in this paper. The in-orbit operational pattern monitoring is reduced to a multi-classification problem, and a discriminant model is constructed to efficiently judge the in-orbit operation mode of the satellite. On the premise of ensuring the accuracy of discrimination, the algorithm model is constructed very quickly, which liberates the monitoring personnel from the heavy rule judgment work and has high practicability. The experiments based on the real telemetry data show that the accuracy rate of the model is 99.9%, which can meet the requirement of in-orbit operation mode monitoring, and can provide references for HXMT satellite operation monitoring task.
Influence of Deformation of Spaceborne Reflectarray Antenna on Its Radiation Characteristics
LIU Yang, WANG Hongjian, ZHANG Lifang
2020, 40(1): 117-125. doi: 10.11728/cjss2020.01.117
Reflectarray, combined the features of reflector and array antenna, has been developed rapidly in last several decades and has been used in many applications. High-gain, low-profile and low-weight planar reflectarray antenna can be widely used in space area. Though several novel reflectarray antennas such as metal-only reflectarray, inflatable reflectarray and transparent reflectarray are designed for space use, the massive applications of reflectarray in space area are not realistic due to the reliability requirements. The fabrication error, assembling error and the heat deformation in high and low temperature will affect the electrical performance of the antenna dramatically. To analyze the changing of the radiation properties resulted from deformation in real environment, the theoretical analysis of the reflection phase for element vertical and horizontal displacement and deformation are carried out. Then two reflectarray antennas with different aperture sizes are designed to find the overall influence of deformation. Scientific calculation with MATLAB and electromagnetic simulation with HFSS are adopted to verify the analysis. The radiation patterns and gain performances of the two reflectarray antennas under several different conditions such as rotation, inverted V-shape deformation and irregular deformation are compared and summarized. The precautions against deformation are also given.
Optical Experiments Prediction of the Quantum Science Experiment Satellite Based on Gradient Boosting Decision Tree
LUO Zhongkai, LI Hu, HU Tai
2020, 40(1): 126-133. doi: 10.11728/cjss2020.01.126
The quantum science experimental satellite mainly carry out four kinds of optical experiments during the orbital operation. The ground monitoring personnel mainly judged whether the satellite carried out optical experiments, experimental types and experimental results through the telemetry parameter threshold. This method requires a large number of thresholds to be set in advance, which requires a lot of manpower, and these thresholds need to be reset according to the on-orbit satellite, and the scalability is poor. Aiming at the above problems, this paper proposes an optical experiment discriminating method based on machine learning. Firstly, the optical experiment monitoring task of quantum science experimental satellite is abstracted into a multi-classification problem in machine learning. A classification model is constructed, and then the quantum science experimental satellite is used. The real historical telemetry data is used to train the model, and finally the trained model is verified by the real experimental plan. The experimental results show that the proposed method can achieve 99% accurate accuracy without the expert prior knowledge, and can be used for real-time monitoring tasks of quantum science experimental satellite optical experiments. The machine learning-based discriminant method proposed in this paper has strong scalability and can be widely extended to other monitoring tasks of satellite orbit operation.
Control System of Mobile Solar Simulator Based on LED Light Source
SU Shi, REN Yiwen, WANG Yiwen, GAI Zhuqiu, ZHANG Yu, ZHANG Guoyu, SUN Gaofei, LIU Shi, ZHANG Jian, YANG Songzhou
2020, 40(1): 134-140. doi: 10.11728/cjss2020.01.134
A mobile solar simulator based on the LED light source is developed to provide simulated sunlight signal and sunlight vector signal. The simulator can be applied to the function test of the field after the installation of the coded solar sensor. Firstly, the structure and working principle of the mobile sunlight simulator are introduced. The control system of the radiance and vector motion of the light source is studied. Secondly, according to the requirements of the sunlight signal, the model and number of LEDs are determined by the light source selection and power calculation. The radiance of the light source is linearly adjusted by the voltage controlled constant current source driving technique. Finally, according to the requirements of the sunlight vector signal, the GUS-60 ultrasonic motor is selected by the load torque and power calculation. The 16-bit absolute encoder is used to measure the moving angle. The digital signal processor is used as the main component to perform closed-loop feedback control of the motor. The experimental results showed that the light source control system could perform linear adjustment within the radiance range of 0~527.4W·m-2. The motion control accuracy of the vector motion device was better than ±0.01° as the motion angle is from -15° to 40°. The mobile solar simulator can help to complete the field test of coded solar sensors.
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