对地观测小卫星的相位噪声分析与控制

结合传输型对地观测小卫星一体化设计的特点，介绍了一种用于对地观测小卫星系统的锁相接收机的-构成及原理，并对系统的相位噪声性能进行了详尽的分析，提出了对其相位噪声进行技术控制的方法。通过文中的分析与研究，消除了由于对地观测小卫星相位噪声所引起的系统误码率的恶化，提高了系统的可靠性，为下一步对地观测小卫星的发展与应用打下了良好的技术基础。     

利用SV分量接收函数反演地壳横波速度结构

详细讨论了远震体波SV分量接收函数的特点及其在反演地壳S波速度结构中的优势．与径向接收函数类似，SV分量接收函数可通过对远震体波的SV分量直接反褶积P分量获得．研究分析表明:与径向接收函数相比，SV分量接收函数的振幅随震中距的变化更加稳定，波形简单且突出了对结构最敏感的PS转换波信息．理论数值实验显示:在反演地壳S波速度结构时，SV分量接收函数比径向接收函数具有更好的收敛性．作为实例，利用SV分量接收函数反演方法反演了海拉尔台下的S波速度结构．      

用远震接收函数研究滇西地区的深部结构

滇西地区地处欧亚板块碰撞或俯冲的边界地带，曾受到多期构造运动的影响，其地质环境和构造背景十分复杂，是我国地震活动比较活跃的地区之一. 本文选用国家、地方和流动数字台网的16个台站的远震记录. 其中PASSCAL甚宽频带流动地震台站4个，提取有效接收函数近2 000条. 两条测线的直线距离分别为650 km和450 km， 横切了滇西地区的一些主要构造单元. 研究表明，怒江断裂可能是一条具有俯冲性质的缝合线. 川滇菱形块体东西两侧的分界线¾红河断裂和小江断裂可能是直立的缝合线或碰撞带. 攀西构造带仍具有大陆裂谷的特征，即地表凹陷、上地幔隆起. 滇西地区的构造格局具有一定的规律性，造山带与缝合线相间分布. 滇西地区由北向南地壳厚度渐次减薄，S波速度整体偏低.      

南方NGS200应用实践中的若干问题

对南方NGS200在工程控制测量领域应用实践中的一些问题作了阐述，提出了一些见解和措施。     

边带分离型超导SIS接收机本振耦合噪声研究

超导SIS (Superconductor-Insulator-Superconductor)接收机因极低的接收机噪声温度成为毫米波和亚毫米波段射电天文观测的首选.本振系统耦合噪声也是接收机噪声的一部分,在多年的天文观测中,发现本振耦合噪声无法完全忽略,对天文观测的灵敏度有一定影响.采用两个不同种类的信号发生器作为本振系统初级信号源,测试了超导SIS接收机的噪声温度,发现信号发生器输出的基底噪声能够耦合到接收机内部,从而增加接收机噪声强度.分析研究了本振系统热噪声和信号发生器基底噪声对接收机噪声的影响.通过在信号发生器输入端加入窄带滤波器滤除其基底噪声,消除了信号发生器基底噪声引入的接收机噪声,降低了接收机的整体噪声,提高了望远镜的灵敏度.     

一种精确估计区域北斗接收机硬件延迟的方法

提出了一种精确估计区域北斗接收机硬件延迟(DCB)的方法。该方法不需要传统复杂的电离层模型,在已知一个参考站接收机硬件延迟的条件下,利用正常情况下电离层延迟量和卫星-接收机几何距离强相关这一特点,采用站间单差法来精确估计区域内BDS接收机的硬件延迟。试验结果表明,该方法单站估计的单站北斗接收机连续30d的硬件延迟RMS在0.3ns左右。通过GEO卫星双频观测值扣除已知卫星DCB和本文方法估计的接收机DCB,计算对应穿刺点一天的VTEC并和GIM格网内插结果并进行比对分析,二者大小和变化趋势均符合较好,进一步验证了本文提出的方法具有可靠性。     

P-waveform analysis for local subduction geometry south of Puget Sound,Washington

The local subduction geometry at a site south of Puget Sound in western Washington is investigated using teleseismicP-waveforms recorded on a three-component event triggered seismograph. The data are processed using source equalization deconvolution in order to isolate locally convertedP-to-S arrivals and stacked to improve the signal-to-noise ratio. Stable arrivals in the radial component indicate an oceanic Moho within the subducted slab at a depth of about 53 km beneath the station. Observed amplitude variations with azimuth in the radial data, as well as qualitative aspects of the tangential data, are used to establish a slab dip of 16° to the southeast. Our results are compatible with previous results from a site 60 km to the west, and further confirm a substantial warp in the regional geometry of the subducted Juan de Fuca plate.     

Simultaneous iterative time-domain sparse deconvolution to teleseismic receiver functions

In this paper, we present a new approach to estimate high-resolution teleseismic receiver functions using a simultaneous iterative time-domain sparse deconvolution. This technique improves the deconvolution by using reweighting strategies based on a Cauchy criterion. The resulting sparse receiver functions enhance the primary converted phases and its multiples. To test its functionality and reliability, we applied this approach to synthetic experiments and to seismic data recorded at station ABU, in Japan. Our results show Ps conversions at approximately 4.0 s after the primary P onset, which are consistent with other seismological studies in this area. We demonstrate that the sparse deconvolution is a simple, efficient technique in computing receiver functions with significantly greater resolution than conventional approaches.     

Crustal structure using receiver function in the east part of A＇nyemaqen suture belt

Twenty broadband seismographs were deployed along Hongyuan, Sichuan to Wuwei, Gansu. 81 teleseismic events were recorded in one year. We computed receiver functions from teleseismic waveform data and obtained S wave velocity structure beneath each station along the profile by using receiver function inversion method. The results revealed that the crustal structure is very complex and crustal average S wave velocity is to be on the low side. Low velocity structure generally exists in the depth range of 10～40 km in the crust between Aba arc fault and northern edge fault of Qinling earth＇s axis and it is a tectonic feature of complex geological process such as ancient A＇nyemaqen Tethys ocean from closing and side colliding to subducted plate exhumed or thrust rock slice lifted. The Moho is about 50 km depth along the profile and is slightly deeper in the south than in the north.     

一种附约束的单频单历元GPS双差相位解算方法

在各类变形观测中，存在着2次观测的变形值不大及各种变形方向和大小可以比较精确预测等特点，可以把这些特征作为约束条件，对GPS单历元相位观测方程进行求解。基于以上几点，提出了一种含约束条件的单频单历元GPS相位求解算法和简单实用的模糊度搜索方法，本方法据观测值直接估计模糊度参数，并根据求出的模糊度估值进行搜索，还分析了最优解的获得和检验方法，最后用2个实例说明了该法的有效性和实用性。