��̫ͬ�������������㷨��GNSS����ϵͳ����Ӱ���о�     

蒋振伟  袁运斌  欧吉坤  杨力 《大地测量与地球动力学》2015,35(2):199-202

?о???????????JPL????????????????????????????GNSS??????λ??????????????????????????????????????????5×10⁸ m???????????????????3×10⁶ m????????????DE421???????????X??????????н?????30′????Y????????X??????????????????????????????λ??????????????????0.3 mm????????????λ?????????????????????3 mm???????????????????1??峱???????????????3 mm???????GPS??????????????????????????????????????PPP??????????????????PPP?в??ü???Ч??????????????  相似文献   

Analysis of the Properties of Super Solar Proton Events and Associated Phenomena     

CHENG Li-bin  LE Gui-ming  LU Yang-ping  CHEN Min-hao  LI Peng  YIN Zhi-qiang 《Chinese Astronomy and Astrophysics》2014

The solar flares, the speeds of shocks propagated in the solar-terrestrial space and driven by coronal mass ejections (CMEs), the heliographic longitudes and Carrington longitudes of source regions, and the geomagnetic storms, which are accompanied by the super solar proton events with a peak ?ux equal to or exceeding 10 000 pfu, have been studied by using the data of ground-based and space observations. The results show that the heliographic longitudes of source regions of super solar proton events distributed in the range from E30? to W75°. The Carrington longitudes of source regions of super solar proton events distributed in the two longitudinal belts, 130°∼220° and 260°∼320°, respectively. All super solar proton events were accompanied by major solar flares and fast CMEs. The averaged speeds of shocks propagated from the sun to the Earth were greater than 1 200 km/s. Eight super solar proton events were followed by major geomagnetic storms (Dst≤−100 nT), except that one super solar proton event was followed by a geomagnetic storm with the geomagnetic activity index Dst=−96 nT, a little smaller than that of major geomagnetic storms.  相似文献   

A Statistical Study of the Relation between the Amplitude of Solar Cycle and the Area of Active Regions     

LI Peng  LE Gui-ming  CHEN Yu-lin  CHEN Min-hao  LU Yang-ping  YIN Zhi-qiang 《Chinese Astronomy and Astrophysics》2014

Based on the observational data of sunspots, the relation between the amplitude of solar cycle and the total area of all active regions occurred in a solar cycle has been investigated. The result shows that the amplitude of solar cycle has a good correlation with the total area of all active regions occurred in the solar cycle. The relation between the amplitude of solar cycle and the area of the largest active region during a solar cycle has also been investigated. The result shows that the amplitude of solar cycle has a poor correlation with the area of the largest active region during a solar cycle, and there is no fixed relation between the peak time of a solar cycle and the time when the largest active region occurred in the solar cycle.  相似文献   

A Study on the CdZnTe Array Detector     

CAI Ming-sheng  GUO Jian-hua  XIE Ming-gang  ZHENG Chun-xiao 《Chinese Astronomy and Astrophysics》2014

The CdZnTe array detector is a new type of semiconductor detector being rapidly developed in recent years. It possesses a high spatial resolution and a high energy resolution, and it can work at room temperatures. This paper describes the physical properties and working principle of the CdZnTe array detector, as well as the manufacturing technology, including the chip pretreatment, passivation, ohmic electrode preparation, array template selection, and array packaging technology (micro-interconnection). For evaluating the perfor-mance of the detector, the authors have developed successfully a 4 pixel×4 pixel CdZnTe array and an 8 pixel×8 pixel CdZnTe array (with the thicknesses of 5 mm and 2 mm, the pixel size of 2 mm×2 mm, and the gaps of 0.15 mm and 0.2 mm, respectively) in cooperation with the partner. A multi-channel electronic readout system based on the ASIC (Application Specific Integrated Circuit) chip is devel-oped independently for the charge measurement of the 4 pixel×4 pixel CdZnTe array. The energy spectra and corresponding energy resolutions of the 16 pixels are obtained with the ¹³⁷Cs radiative source, among them the best resolution is 4.8%@662 kev.  相似文献   

Linear Correlations between Peak Frequency of Gyrosynchrotron Spectrum and Photosphere Magnetic Fields     

Ai-Hua Zhou Jian-Ping Li 《中国天文和天体物理学报》2007,7(4):487-495

The gyrosynchrotron spectra are computed in a nonuniform magnetic field case, taking into account the self-and gyroresonanceabsorption. It is found that the peak frequency νp of the gyrosynchrotron spectrum systematically increases with the increasing photosphere magnetic field strength B0 and increasing viewing angle θ. It is also found for the first time that there are good positive linear correlations between νp and B0, and between log νp and log θ, with linear correlation coefficient 0.99 between νp and B0 and 0.95 between log νp and log θ. We apply the correlations to analyze two burst events observed with OVSA and find that the evolution tendencies of the photosphere magnetic field strength B0 estimated from the above expression are comparable with the observational results of SOHO/MDI. We also give a comparison of the diagnostic results of coronal magnetic field strength in both uniform and nonuniform source models.  相似文献   

太阳暗条活动的周期性研究     

宋文彬  汪景琇 《天文学报》2007,48(1):29-35

运用法国巴黎默东天文台记录的暗条目录资料构造了一个时间精度为每天的暗条数目序列,选用Scargle周期图和Morlet小波变换两种周期方法研究了这个序列的周期性,发现其存在4个显著的周期,它们分别是1557天、1141天、795天和367天,详细分析了这些周期的时变特征,并简单讨论了其中个别典型周期的相位、物理机制和相互关系．  相似文献   

GPS定轨中的太阳辐射压模型   总被引：5，自引：0，他引：5  

陈俊平  王解先 《天文学报》2006,47(3):310-319

对于GPS这样的高轨卫星轨道的确定,最大的误差源为太阳辐射压摄动．近年来IGS各个数据处理中心提供的GPS星历精度越来越高,其中很重要的一个因素就是太阳辐射压摄动模型的不断完善．详细阐述了目前主要的7种太阳辐射压摄动模型后,给出了各种光压摄动模型的计算模型,并利用不同的摄动模型积分卫星轨道,得到不同模型在GPS卫星轨道积分中的精度．结果表明,Bern大学提供的3种模型对太阳辐射压的模拟较为准确,相对于其他4种模型,由其得到的GPS轨道精度有将近一个量级的提高．  相似文献   

微波Ⅲ型爆发的观测特征     

马媛  谢瑞祥  郑向明  颜毅华 《天文学报》2006,47(1):46-53

统计分析了国家天文台2．6-3．8 GHz高时间分辨率射电动态频谱仪在23周峰年期间(1998．4—2003．1)观测到的266个III型爆发．对这些事件的频率漂移、持续时间、偏振、带宽、开始和结束频率做了详细分析．开始和结束频率的统计分析表明,开始频率在一个非常大的范围,从小于2．6 GHz到大于3．8 GHz,而结束频率的截止区相对集中,从2．82-3．76 G．Hz．这些现象说明,电子加速的高度相当分散,在观测频率范围内具有正、负漂移率的III型爆发数基本相等,这可能意味着被加速的向上和向下传播的电子束在2．6—3．8 GHz范围有相同的比例．统计结果表明,微波III型爆发的辐射机制主要是等离子体辐射和电子回旋脉泽辐射过程．  相似文献   

太阳耀斑亮核和硬X射线环顶源运动的初步分析     

周团辉  季海生 《天文研究与技术》2006,3(2):210-216

分析了2个耀斑事件。这2个耀斑事件都具有双带结构，并伴有耀斑环顶部位置的硬X射线（HXR）辐射，这个辐射源我们称为环顶源。在文章中，通过求亮度重心的方法，我们对耀斑双带的相对运动，以及HXR环顶源的高度变化进行了分析。结果表明：耀斑相偶亮核间距离的时间曲线，与HXR亮度曲线具有相反的相关性，亮核间距离在HXR流量上升阶段会减少；与此同时，HXR环顶源的高度会下降。而通常的相偶亮核的分离运动以及环顶源的上升运动发生在极大相之后。  相似文献   

成都近十年大气稳定度综合研究     

孟庆珍  周建军  陈敏 《成都信息工程学院学报》1997,(1)

按新颁国家标准ＧＢ／Ｔ－１３２０１－９１中规定的稳定度分类法，统计了成都近十年的大气稳定度频率，研究了其分布特点和变化规律，并探讨了变化原因。对新标准中的日夜分界及δ取值法提出了相应的建议和简化意见  相似文献