Subjects: Geosciences >> Space Physics submitted time 2017-03-10
Abstract：太阳跟踪研究的发展，向太阳跟踪器的控制系统智能化提出了更高的要求。以SOLYS Gear Drive 太阳跟踪器为仪器平台，创新性地提出利用路由器建立控制主机和太阳跟踪器在局域网内，以及局域网和互联网之间的通信,并以虚拟仪器开发软件LabVIEW为软件平台，综合调用百度地图应用程序接口API和指令脚本文件，设计了一套控制系统。实现对仪器的状态监测，指令控制，远程访问等。系统功能丰富，操作简单，界面可视化好，普遍适用性强。
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： In order to ensure quantum science experiments can be developed smoothly, a high data rate two-way link for Space-Ground microwave communication must be established. Via following the study on Consultative Committee for Space Data Systems (CCSDS) and taking into account the scientific requirements of microwave communication link for quantum science experiment satellite, the physical layer hardware architecture and modulation/demodulation algorithm of microwave communication link for the satellite are presented.The uplink modulation type of the microwave communication link is SRRC-OQPSK, which accord with CCSDS spectrum standard. The specification of uplink data rate is 1.024Mbps,. The downlink modulation type of the microwave communication link is SRRC-OQPSK/GMSK, and the data rate is 4Mbps. By compatible tests with several ground stations, we find that the sensitivity of carrier acquisition is superior to -100dBm, and AGC ability is greater than 43dB. Moreover, the bit error rate of actual transmission is superior to 1�0-9 as the received signal level is equal to -96 dBm. The measured results indicate that the physical layer design scheme of microwave communication link meets the requirements of space quantum science experiments.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Multi-point synchronous magnetic field measurements can give more accurate space current density compared with the traditional single-point measurement, since multi-point measurement can eliminate the temporal change in the magnetic field. Based on the current density inversion method for multi-point magnetic field measurements, through simulation, several factors affecting space current density inversion are analyzed, such as the number of satellites, satellite formation configuration, satellite positioning precision, satellite attitude determination error, magnetic field measurement accuracy, external magnetic field intensity, external current density and so on. It is shown that 5-point measurements are better than 4-point measurements, and error in attitude determination and external magnetic field intensity are the main factors causing the error in current density inverted, while satellite formation configuration is also an important factor. According to the simulation, the maximum error in current density is less than 24% near the equator when the attitude determination error is 0.001癮nd the scale of the satellite formation is about 100km.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： By studying Rayleigh lidar data，The seasonal variations of atmospheric temperature of 35-70km in Beijing area are analyzed.The atmospheric temperature between 30-70km height range at Beijing region has obvious annual cycle variation. The highest temperature in the stratosphere appeared in June and July, which is about 270K. The lowest temperature in the middle layer 70km is also in June, July, about 200K. Take the data of October 14, 2014 as an example， Gravity wave dissipation under 50km is found，while， the gravity waves propagate upward almost without dissipation above 50km.By comparing the average potential energy density between 35-50km height range, the seasonal variation of the gravity waves activities intensity in the Beijing area was studied. The gravity waves activities over Beijing have an obvious cycle of one year.The average potential energy density in winter is , while in summer, the average potential energy density is , the gravity waves activities intensity in winter is about two times of that in summer. In addition, the profile of seasonal averaged gravity waves potential energy density are given in spring,summer,autumn and winter. The dissipation of gravity waves in different seasons and different heights is analyzed in Beijing area.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： A general design of solar neutral atom code mask imager (SONACOMI) is proposed. The instrument is designed to measure the solar energetic atom emitted from the solar flare or CME, measuring the differential energy spectrum of ENAs between 0.5MeV/u and 6MeV/u and FOV of ENAs covering . This instrument combines innovative sensor geometry, an m series coding mask modulation aperture, and a combination of high voltage deflecting plate of active and passive shielding charging particles to obtain ENAs in space flight.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： This study use the wind data from the observation of China Langfang (39°N，117°E) meteor radar during the 1 April 2012 to 31 March 2013 to investigate the features of the mesospheric and lower thermospheric mean winds within 80-100 km altitude regions. The results show that the mean zonal winds and mean meridional winds both have obviously seasonal variations. During the winter, eastward winds prevail in the MLT ranges, which is strong in mesosphere and decrease versus increasing altitude. In the summer, westward winds dominate in mesosphere, and decrease along with increasing altitude, then turn to the strong eastward in lower thermosphere. The wind evolution in the spring and autumn are the transition characters between the summer and winter. The mean meridional winds are southward in summer and northward with sometimes reversal in winter, in general. The above main seasonal variations of mean winds are captured largely by the simulation of WACCM4 model and HWM93 model. WACCM overestimates the winds, but HWM93 underestimates the winds.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Parameterized ionosphere model TIEGCM is used as background model. Basing on the COSMIC observations, global ionospheric electron density assimilation model is established using ensemble Kalman filter. Result shows, this model can effectively assimilate observations into background model and acquire three dimensional ionospheric electron density. Compared to background, the error between analysis and observations decreases significantly. The root mean square error(RMSE) of NmF2 decreases about 60% for observations assimilated, and 20% for observations not assimilated. The RMSE of hmF2 doesn’t get improvement except for mean error. The results of simultaneous assimilation (SA) and batches assimilation (BA) are compared for this case. The time that the two methods spend in assimilation is about 6 to 7 minutes, which does not differ very much. SA needs nearly 8 GB storage while BA less than 2GB. The statistic of electron density error shows that they nearly acquire the same mean error, but the SA gets relative better improvement in RMSE above 250km.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： The problem of minimum-fuel aeroassisted orbital transfer of a high lift-to-drag ratio vehicle from Low Earth Orbit (LEO) or Geostationary Earth Orbit (GEO) to low-Earth orbit with an inclination change is considered. Assuming impulsive thrust, the trajectory design is described in detail and the aeroassisted orbital transfer is posed as a nonlinear optimal control problem. Through comparison of the double-impusive orbit transfer and aeroassisted orbit Transfer in noncoplanar orbit, we concluded the influence of altitude difference from two noncoplanar orbits and the perigee choice of the middle transtion orbit. The main problem that aeroassisted orbital transfer may face is hypersonic flight in the upper atmosphere. In the end the technology used in X-37B flight was concluded.
Peer Review Status:Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2017-01-22
Abstract： Solar proton event forecast is very important to guarantee the security of spacecrafts and astronauts. According to the short to medium term space mission, the greater than 10 MeV, 30 MeV and 60 MeV solar proton event fluences are statistically analyzed. It is found that the probability distributions of solar proton event fluences basically satisfy the log-normal distributions, and their expectations and averages are logarithmic functions of the time periods. Based on these, a short to medium term forecast model of solar proton event fluences is built, which can forecast the greater than 10 MeV, 30 MeV and 60 MeV solar proton event fluences with some given confidence levels for 1 to 365 days. So, this model is very helpful to safely carry out the space mission with less than 1 year mission period.
Peer Review Status:Awaiting Review
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