低频时码信号场强计的研制

介绍了BPC低频时码信号场强计的设计方案和原理,并结合出仪器硬件设计和控制软件框图,该仪器体积小,重量轻,测量精度高,对低频时码系统工程应用和低频电波传播特征研究具有重要意义。     

BPM短波时码授时发播技术方案

为适应时频技术的迅速发展,进一步提高BPM短波授时发播系统的服务能力,扩展短波授时服务领域的用户面,在原有的BPM短波授时发播程序中增加短波时码信息是十分必要的.本文介绍了BPM时码授时发播的总体设计方案、BPM时码的格式以及解码流程等.     

BPL时码发播和自主授时方法

在对国际上普遍采用的3种罗兰-C数字调制方法分析比较的基础上,对我国BPL长波授时发播系统技术改造中选用的数字调制方法、时码发播和自主授时方法进行了介绍,并提出了实现BPL时码发播和自主授时后宜采用的闰秒方案.     

UTC闰秒通知

2008年12月末,协调世界时(UTC)系统将引入1正跳秒。届时,我国综合原子时系统的协调世界时UTC(JATC)、国家授时中心的协调世界时UTC(NTSC)及其所控制的实时时间UTC(NTSC MC),以及BPL、BPM、BPC长短波授时信号和低频时码信号中的UTC时号都将     

UTC闰秒通知

2012年6月末,协调世界时(UTC)系统将引入1正跳秒。届时,我国综合原子时系统的协调世界时UTC(JATC)、国家授时中心的协调世界时UTC(NTSC)及其所控制的实时时间UTC(NTSC MC),以及BPL、BPM、BPC长短波授时信号和低频时码信号中的UTC时号都将实     

UTC闰秒通知

<正>2012年6月末,协调世界时(UTC)系统将引入1正跳秒。届时,我国综合原子时系统的协调世界时UTC(JATC)、国家授时中心的协调世界时UTC(NTSC)及其所控制的实时时间UTC(NTSCMC),以及BPL、BPM、BPC长短波授时信号和低频时码信号中的UTC时号都将实     

一种提高CAPS导航通信融合系统保密性的新方法

根据导航通信融合系统的特点,通过伪随机序列码与混沌序列码的复合得到GC(Gold-Chebyshev)序列码,新序列码克服了混沌序列平衡性差的缺点,满足了系统短码的要求,得到的GC序列具有码组数量几乎无限多和序列线性复杂度好的优点。系统以伪随机跳变的方式更换码序列集合,极大地提升了系统的安全性。对换码模式和系统性能进行实验验证,表明复合新码GC序列采用换码模式易于实现可靠通信,还可以有效提高系统的保密性能。     

时间扩频码信号及研究(摘要)

扩频码又叫测距码或伪随机噪声码。人们已对它作了广泛的研究,它的应用已随着对其研究发展而迅速扩展,除应用于通信、雷达、导航及密码学外,还应用于自动控制、计算机、声学与光学的测量、数字式跟踪、测频及数字网络等方面。本文所研究的是最长周期的伪随机序列(m序列)。及其短截式m序列。详细分析了     

基于虚拟仪器技术的低频时码信号采集平台设计

介绍了最新的虚拟仪器开发平台LABVIEW的特点及应用 ,提出了利用LABVIEW实现低频时码信号的采集与显示的一种设计方法。该设计采用了软件设计技术 ,大大降低了测试设备系统的成本 ,并对于低频时码信号的分析与处理具有了更大灵活性。     

双口RAM在低频时码信号采集系统中的应用

介绍了一种快速双口RAM芯片 IDT7026的结构特点和功能，并将其应用于低频时码信号采集系统中，从而实现了DSP(数字信号处理器)和单片机进行快速数据传输和数据共享的任务。给出了通过该芯片进行DSP和单片机通信的具体接口电路，并针对低频时码信号采集系统中交换数据的仲裁方式，提出了令牌传递和软件判优两种实现方法。     

The Model of Radio Two-way Time Comparison between Satellite and Station and Experimental Analysis

Time synchronization between satellite and station is the key technique of satellite navigation system and the foundation of realization of satellite navigation and positioning. Aiming at solving the problems of time synchronization, we have discussed a new method of radio two-way time comparison between satellite and station, deduced in detail the reduction model of up- and down-link pseudo ranges between satellite and station, and provided a practical calculation model of clock error between satellite and station. By calculating the differences between up- and down-link pseudo ranges, this method has eliminated the influences of common errors, such as the tropospheric delay, satellite ephemeris errors, ground station coordinates errors and so on. The ionospheric delay relevant to signal frequency is also weakened largely, thus this improves the accuracy of time comparison greatly. Finally, experimental analysis is conducted by using observational data, and the results show that the accuracy of radio two-way time comparison between satellite and station can attain about 0.34 ns, which validates the correctness of theoretical method and model.     

DDS输出频谱特点及改善方法

利用非均匀采样模型得到了存在相位截断时直接数字频率合成（ＤＤＳ）的输出频谱,通过分析频谱特点,讨论了改善频谱分布的方法     

Russian-Cuban Colocation Station for Radio Astronomical Observation and Monitoring of Near-Earth Space

The article presents the main possibilities of using the projected Russian-Cuban geodynamic colocation station on the basis of the Institute of Geophysics and Astronomy of the Ministry of Science, Technology and the Environment of the Republic of Cuba to carry out radio observations and monitoring the near-Earth space. Potential capabilities of the station are considered for providing various observational programs: astrophysical observations; observations by space geodesy methods using radio very long baselines interferometers, global navigation satellite systems, laser rangers, and various Doppler systems, as well as monitoring of artificial and natural bodies in the near-Earth and deep space, including the ranging of asteroids approaching the Earth. The results of modeling the observations on the planned station are compared with that obtained on the existing geodynamic stations. The efficiency of the projected Russian-Cuban station for solving astronomical tasks is considered.     

Analysis of radio astronomy bands using CALLISTO spectrometer at Malaysia-UKM station

The e-CALLISTO system is a worldwide network that aims to observe solar radio emission for astronomical science. CALLISTO instruments have been deployed worldwide in various locations that together can provide continuous observation of the solar radio spectrum for 24 h per day year-round. Malaysia-UKM is a strategic equatorial location and can observe the Sun 12 h per day. This paper gives an overview of the spectrum allocation for radio astronomy, which falls in the specified operating frequency band of the CALLISTO spectrometer. The radio astronomy bands are analyzed at the Malaysia-UKM station according to the International Telecommunication Union recommendations. Some observational results are also presented in this paper.     

太阳射电频谱日像仪光纤传输技术分析与性能测试

分析了光纤传输系统的特性，及其对太阳射电频谱日像仪的影响。根据日像仪系统的传输性能要求，对四种光纤传输方案进行了综合比较，最终选择模拟光纤传输系统作为建设方案。在选定方案的基础上对相关设备的性能进行了测试，并针对设备测试与对卫星信号的现场实际相关接收测试结果进行分析，验证了拟定方案的可行性。最后，提出构建太阳射电频谱日像仪光纤传输系统需要进一步解决的问题和需深入探讨的内容．     

Equipment and observational technique used to obtain dynamic spectra of the solar radio radiation at the KRIM station

The equipment and observational technique used to obtain dynamic spectra of the solar radio radiation at the KRIM station (Crimean Astrophysical Observatory) that is a part of the e-CAL-LISTO worldwide network are described. The parameters of an antenna fabricated in the Radioastronomy Laboratory of the Crimean Astrophysical Observatory and a method for excluding the instrumental distortions that was developed at the KRIM station are outlined.     

Search for groups of extragalactic radio sources

We explore the possibility of searching for groups of radio sources from the FIRST catalog on angular scales 1′–5′. We developed an efficient method of searching for such groups that takes into account the need for combining the components of extended sources represented in the catalog by separate objects. We found 31 groups of radio sources with angular sizes <5′ that contain no fewer than five sources with flux densities ≥3 mJy. This number is at least triple the expected number of such groups for a random Poisson distribution of radio sources in the sky. The prospects for using groups of radio sources to detect and study distant systems of galaxies are discussed.     

Fast radio burst search: cross spectrum vs. auto spectrum method

The search for fast radio bursts(FRBs) is a hot topic in current radio astronomy studies. In this work, we carry out a single pulse search with a very long baseline interferometry(VLBI) pulsar observation data set using both auto spectrum and cross spectrum search methods. The cross spectrum method,first proposed in Liu et al., maximizes the signal power by fully utilizing the fringe phase information of the baseline cross spectrum. The auto spectrum search method is based on the popular pulsar software package PRESTO, which extracts single pulses from the auto spectrum of each station. According to our comparison, the cross spectrum method is able to enhance the signal power and therefore extract single pulses from data contaminated by high levels of radio frequency interference(RFI), which makes it possible to carry out a search for FRBs in regular VLBI observations when RFI is present.     

Relationships between radio aurora,visual aurora and ionospheric currents during a sequence of magnetospheric substorms

In an earlier paper the latitudinal and longitudinal structure of ionospheric current flow during a sequence of magnetospheric substorms was presented (McDiarmid and Harris, 1976). In the present paper the relationships between the electrojets, the radio aurora observed at 48 MHz and the all-sky camera-recorded visual aurora are presented for the same substorm sequence. The previously described morphology of radio aurora during substorms is confirmed and the observed relationships can be explained.     

Homology of X-ray bursts

Conclusions The present paper demonstrates on the basis of 2 series of events that one can extend the homology so far known for optical and radio flares also to the hard and soft X-ray bursts.The studied homologous X-ray flares occurred in the same active region and their time-intensity profiles were very similar. It has been found that the detected homologous X-ray bursts are associated with radio bursts that also are homologous. The time profile of centimeter radio bursts frequently is repeated in detail when compared with the time profile of X-ray bursts as one can see in Figure 1. This very close correspondence suggests that the centimeter radio bursts and X-ray bursts are generated simultaneously during flares, probably in the same region (Sengupta, 1968). Arnoldy et al. (1968) have found a detailed correlation between the time-intensity profiles of hard X-ray bursts and 3 or 10 cm radio bursts. This close correlation between the hard X-ray bursts and centimeter radio bursts leads to a suggestion that the hard X-ray and centimeter radio bursts are generated by the same electrons. On the basis of these considerations one can more easily understand the homology of both the X-ray bursts and the radio bursts. The occurrence of homologous bursts then can be explained by an existence of regions on the sun in which for a certain time (48 h after Fokker) the same conditions are maintained in the acceleration of the electrons generating the X-ray and radio bursts.