CINRAD-SA/SB发射机故障定位方法

介绍了CINRAD-SA/SB发射机信号流程、同步信号时序关系及关键点波形参数,从故障现象、雷达终端报警信息、面板监控信息分析入手,根据相关信号流程和关键点波形、参数测试,定位发射机故障到可更换单元,总结了速调管附属电源、高频放大链、全固态调制器电路故障分析定位技巧,列举了用调压器法、断开负载法、逐级检测法分析定位全固态调制器电路故障的典型个例,并提出了发射机维修方面的一些建议。     

Co-Phased Median Filters, Some Peculiarities of Sweep Signal Processing

Median filters are nonlinear and a theoretical analysis of their behavior is very difficult and so are rarely used for the processing of seismic data. However, they are able to preserve steps, sharp discontinuities and edges that are lost using most other standard filters. As seismic data are mostly harmonic or frequency modulated signals in the frequency range 1 to 10 Hz, the median filter must be adapted so as to suppress noise but not unduly distort the signal. This can be accomplished by using a median filter whose length is n times that of signal period where n is even. By use of weighted-order statistics, samples of the signals closest in phase can be obtained. To illustrate the method, a signal from a frequency band of 6.3–7.5 Hz was processed and the quality of the signal enhanced two fold over the quality of the signal without processing.     

远程事件次声监测中的信号参数二维子空间计算方法

越来越多的观测发现,在地震、火山爆发、泥石流等重大自然灾害发生前,常产生异常的次声信号,这为地震及其他自然灾害的预报工作增加了一种可能的信息;同时,次声还是监测大气层、浅地表爆炸的有效手段.在自然灾害和爆炸事件次声监测中,慢度和方位角等参数对于源信号传播、定位以及源性质识别等工作具有重要意义.然而,目前的慢度和方位角等参数的算法--频率波数（FK）分析法,尚存在精度和分辨率不高等问题,特别是对多源次声信号的识别能力较差.为提高次声信号的监测精度,基于次声信号和噪声的子空间不相关性,构建了次声信号慢度和方位角二维子空间计算模型,并在此基础上提出了一种高分辨率次声信号二维子空间算法,仿真实验和实际数据的对比分析结果表明：本文提出的方法在精度和分辨率方面明显优于FK法,且能够更好地分离多源次声信号.

     

基于PCA及提升小波组合算法提取建筑物结构振动信号

针对监测结果受测量噪声和多路径等GPS误差影响的问题,提出基于PCA及提升小波的组合算法来提取建筑物结构振动信号。利用PCA空间滤波分离区域站点相关的共模误差,然后利用提升小波变换对振动信号进行降噪,用于提取结构振动信号。以香港某高楼在台风荷载作用下的观测数据为例进行实验,结果表明,此算法有效提高了变形监测的精度。     

长江中游地区暴雨过程的气候背景分析

通过用气候信号场研究长江中游地区暴雨发生的气候异常环境,提出了关于信号场的合成图的检验方法,应用到暴雨规律分析中。分析表明,暴雨与500hPa信号场中异常信号显著区的出现在我国东部上空,分布形势呈‘+-+'的波列是暴雨发生的重要征兆。     

温家沟-东山金银及多金属成矿带电法找矿效果和找矿模式

本文介绍了冀北温家沟－银及多金属成矿还上电法的找矿效果,并根据该成矿带上电性参数特征、电法异常与金、银及多金属矿（化）体的对应关系,归纳出该成矿带的电法找矿标志和找矿模式。     

Analytic signal approach and its applicability in environmental magnetic investigations

We investigate the analytic signal method and its applicability in obtaining source locations of compact environmental magnetic objects. Previous investigations have shown that, for two-dimensional magnetic sources, the shape and location of the maxima of the amplitude of the analytic signal (AAS) are independent of the magnetization direction. In this study, we show that the shape of the AAS over magnetic dipole or sphere source is dependent on the direction of magnetization and, consequently, the maxima of the AAS are not always located directly over the dipolar sources. Maximum shift in the horizontal location is obtained for magnetic inclination of 30°. The shifts of the maxima are a function of the source-to-observation distance and they can be up to 30% of the distance. We also present a method of estimating the depths of compact magnetic objects based on the ratio of the AAS of the magnetic anomaly to the AAS of the vertical gradient of the magnetic anomaly. The estimated depths are independent of the magnetization direction. With the help of magnetic anomalies over environmental targets of buried steel drums, we show that the depths can be reliably estimated in most cases. Therefore, the analytic signal approach can be useful in estimating source locations of compact magnetic objects. However, horizontal locations of the targets derived from the maximum values of the AAS must be verified using other techniques.     

贵州织金浅煤层地震勘探技术的实践与认识

贵州织金地区二叠系龙潭组煤层连片稳定分布、累计厚度大,为中高阶煤煤层气重点有利目标区;但主力煤层地震反射资料信噪比低、剖面成像效果差,制约了该区煤层气勘探开发工作。工区内灰岩大面积裸露、目的层埋藏浅是导致该区地震资料信噪比低的最主要因素。实践表明：基于数字盒子波调查的模拟检波器多道组合接收技术具有较好的噪声压制效果,基于煤层反射最大信噪比的岩性-井深-药量匹配激发技术提高了地震激发效率,宽线观测、小道距数字检波道组合技术是改善二维地震成像的有效方法,小道距、小线距、高炮密度及高横纵比的三维地震观测技术显著提升了煤层资料品质。该技术系列适用于山地灰岩出露地区浅煤层地震采集。     

Anubis的GNSS数据质量检核可视化表达与分析

针对目前TEQC数据质量检核软件尚不支持同时检核GPS/BDS/GLONASS/Galileo四系统观测数据质量的现状,该文基于开源代码的Anubis命令式窗口软件,重新编译Anubis软件代码,以扩展北斗导航系统新频点新信号数据的处理功能;依托Python平台实现Anubis软件的可视化界面封装以及质量检核结果的可视化输出,并对其软件功能和检核结果有效性进行验证。实验结果表明,改进后的Anubis软件能够以多种质量指标有效检核GNSS数据,满足检核新一代iGMAS接收机数据质量的需求。     

GPS中频信号快速捕获技术分析

为解决GPS中频信号快速捕获问题,在介绍GPS码相位和载频信号捕获原理的基础上,重点阐述了基于FFT的并行GPS中频信号快速捕获方法,同时在非相干累加、接收信噪比、先验信息等方面分析了提高中频信号快速捕获的可能性,最后利用一组GPS实测数据对上述分析进行了的仿真计算。仿真结果表明基于FFT技术的中频信号快速捕获方法具有抗干扰、捕获速度快和检测低信噪比信号的能力,可以满足GPS软件接收机定位的要求。