基于GPS软件接收机的SINS／GPS紧组合系统仿真

为了系统验证SINS／GPS紧组合系统的性能,基于GPS软件接收机,进行了仿真系统构建。仿真系统由轨迹发生器、GPS中频信号模拟器、IMU信号模拟器、GPS软件接收机、SINS导航解算模块、组合滤波算法和导航性能分析模块等部分构成,其中详细设计了GPS软件接收机中的捕获和跟踪算法、SINS解算以及基于伪距和伪距率的组合滤波算法。仿真结果表明：紧组合导航系统收敛性较好,能够一定程度上抑制惯导系统误差的积累,有较好的导航性能。设计的该系统满足紧组合导航系统性能验证的需要,也为后续的超紧组合研究奠定了良好的基础。     

浅层弯线地震勘探采集与处理技术

在浅层地震勘探中,测线常常由于场地的限制而不能沿直线布设.而弯线地震勘探施工过程中炮检中点比较分散,影响共面元道集的叠加和最终剖面的真实性.加之浅层地震资料又有其自身的特殊性,所以选择合理有效的浅层弯线采集与处理技术非常必要.本文以甘肃陇南山区新文县一中测线为例,结合弯线共中心点面元叠加的时间、空间条件,在采集和处理两个环节分析控制炮检中点分散范围的具体方法,获得了真实且高品质的地震剖面.剖面有效波的能量较好,同向轴连续清晰,各种干扰波得到了压制,说明浅层弯线地震勘探的方法在理论上和技术上都是可行的.     

Sedimentary and upper crustal structure of Australia from receiver functions

The initial coda of teleseismic P‐waves contains considerable information about the crust and upper mantle structure directly beneath a receiver. When this information can be recovered for a dense network of seismographs much can be learned about the structure of the earth. Data from the high quality broadband seismic stations of the SKIPPY and KIMBA projects along with permanent stations are used to investigate the upper crustal structure of Australia. A dataset of 65 shear‐velocity models derived from receiver functions has enabled the sedimentary and upper crustal structure of Australia to be summarised. Regions of thick soft sediment show good agreement with topographical lows. A simple relation between upper‐crustal velocity and magnetisation, as has been suggested by other investigators, has not been observed, but this may be due to the magnetic signal being muted by overlying sediments. A prominent mid‐crustal discontinuity is apparent in the Tasman and New England mega‐elements. This may represent a mid‐crustal décollement that had structural control during accretion.     

Tasman Geosyncline greenstones and ophiolites

Palaeozoic greenstones lying at the base of stratigraphic sequences or in fault blocks in the Tasman Geosyncline are compared with the Penrose Conference definnition of an ophiolite by using tabulated petrological, structural, and metallogenic data. Of 45 occurrences, only 9 are recognizably ophiolites: 4 are in rift zones adjoining Precambrian continental crust at the ends of the geosyncline; and away from the margins, in that part of the geosyncline most typically of West Pacific‐type, only 5 of the 33 greenstone occurrences are recognizably ophiolites. Ophiolites are rare in the Tasman Geosyncline, in contrast to several Atlantic‐type geosynclines. This may be a characteristic of West Pacific‐type geosynclines in general.

Alpine‐type serpentinites are rather common in the Tasman Geosyncline. The metallogeny of some shows affinities with ophiolites, suggesting a common origin as oceanic crust. Their relative abundance suggests that West Pacific‐type geosynclines, such as the Tasman Geosyncline, may have developed on oceanic crust of unusual composition. Alternatively, it may reflect differences of deformation style between Atlantic‐ and West Pacific‐type geosynclines.

The term ophiolite has been used uncritically in plate tectonic analyses of the Tasman Geosyncline, calling in question the objectivity of these analyses. If objectivity is to be maintained, some indication should be given of the quality of the data used in plate tectonic analyses.     

纳土纳(Natuna)地震台建设及初步结果

简述了在南海纳土纳岛(Natuna Islands)建设地震台站的意义和设备.用获得的首批观测资料,分别采用接收函数方法和ScS波分裂技术反演了纳土纳地震台下面地壳的S波速度结构和各向异性参数.结果表明纳土纳地震台下方地壳厚度约28 km,为典型的陆壳性质,上地幔40～50 km为低速层.纳土纳的地壳快波方向为S62°E,与GPS测量的亚洲南部巽他块体的地壳运动方向一致.     

Preliminary analysis of teleseismic receiver functions of the Ningxia and its adjacent area

The teleseismic receiver functions of digital seismic network of Ningxia and its adjacent area are calculated with two different Gauss filter factors. The accuracy and stability of the receiver functions are discussed. The h-k stacking method is applied to estimate the crustal thickness and velocity ratio beneath seismic stations. The results indicate that there are sharp changes of crustal thickness and velocity ratio in the studied region. This region is located in the northeastern margin of Tibet, and also a junction of several first-grade blocks. The large contrast of crustal structure in this region is considered to be resulted from the interaction of these blocks. Our results are helpful to construct the completed model of the formation and evolution of the Tibet. Some local structures are also discussed combining with the geological faults.     

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多波束测深系统内部参数的设定与校准

以EM710RD多波束测深系统为例,通过高精度测量获得的系统参数,对该系统内部参数的设定与校准过程进行详细分析,从而为多波束测量外业工作提供参考依据。     

基于多波束测深系统的水下成像技术

为实现多波束测深系统的一体化探测功能,研究分析了利用快拍法进行多波束水下成像的基本原理,并考虑实际中的水声环境和多波束测深系统自身的复杂性,对用于成像的位置数据和散射强度数据进行了修正,湖上试验数据的处理结果表明了该方法对水中目标的探测能力,验证了其工程应用的可行性。     

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