共查询到18条相似文献，搜索用时 375 毫秒
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从GPS基本观测模型出发,给出并推导了分离相位小数偏差求解非差整数模糊度的精密单点定位数学模型和算法.利用少量IGS跟踪站组成服务端观测网计算未检校的相位小数偏差改正信息,用于改正用户端接收机的相位观测值,实现了固定非差整数模糊度的快速精密单点定位与定轨.试验结果表明: 利用30 min的地面动态或静态观测数据进行精密单点定位,非差模糊度固定成整数后,其定位结果较PPP浮点解有明显改善,水平方向提高了近一个数量级,可达到1 cm甚至毫米级的精度;高程方向与对流层延迟解算精度也改善了20%~60%.与浮点解相比,固定解能显著改善PPP的定轨精度,仅用15 min的短弧段观测数据,切向与法向的定轨精度可达到1 cm左右;径向方向为3~5 cm左右,较浮点解定轨精度改善了50%~70%.因此,固定非差整数模糊度后的PPP能够满足毫米至厘米级的快速精密定位和定轨的要求,这在GPS(准)实时应用与服务中具有很好的应用前景. 相似文献
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高精度的卫星轨道确定是卫星应用的基础和保证,本文以新一代DORIS接收机观测数据DORIS 3.0的相位观测数据为基础,研究了相位观测数据与传统的DORIS距离变化率数据的转换方法,并以JASON-2卫星为例,基于卫星动力学定轨原理,分析了不同数据类型、不同定轨方案得到的卫星轨道精度.结果表明,1)利用3天弧段的DORIS 2.2格式距离变化率数据和数据文件提供的相位中心偏差改正,或者采用模型对天线相位中心偏差进行改正并同时对地面测站进行偏心改正时,两种方案得到的轨道三维位置精度基本一致,均优于8.7cm,说明新一代DORIS接收机相位中心稳定,变化较小,采用模型进行偏差修正完全能够满足定轨精度要求.2)采用3.0格式的DORIS数据以及天线相位中心偏差修正模型和地面测站偏心改正模型时,得到的卫星定轨精度略有降低,大约为9.2cm;SLR校核残差约为6.5cm(均方根误差).3)采用2.2和3.0两种格式的DORIS数据,利用不同的定轨方案对JASON-2卫星进行精密定轨,均可以达到2cm左右的径向定轨精度,不同的定轨方案对径向定轨精度的影响可忽略不计.因此,对于最关心卫星径向定轨精度的海洋测高卫星而言,采用本文的数据格式转换方法和定轨方案,完全可以满足其定轨任务需求. 相似文献
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基于星载GPS的HY-2卫星高精度精密定轨模拟研究(英文) 总被引：2，自引：0，他引：2
HY-2卫星是我国第一颗测高卫星,其径向定轨精度要求厘米量级,搭载了星载GPS接收机。目前HY-2还处于测试阶段,没有公布观测数据。为了确定基于星载GPS的HY-2精密定轨流程及其定轨精度,本文模拟了HY-2卫星星载GPS观测数据,结果表明HY-2星载GPS天线每个历元至少观测7颗GPS卫星。给出了基于星载GPS的精密定轨流程,分别采用简化动力学方法和动态几何法进行了精密定轨实验。对于相位1mm和3mm随机误差的相位观测数据,简化动力学法和动态几何法定轨都能够实现厘米量级的径向精密定轨,几何法定轨精度略低于简化动力定轨。地球重力场模型是影响HY-2卫星精密定轨的重要因素,本文对不同阶次的重力场模型EIGEN2、EGM96、TEG4和GEMT3进行了简化动力学定轨实验,高于50阶次的重力场模型都能够实现厘米级径向精密定轨,主要原因在于大量的高精度星载GPS观测数据和重力场模型精度的提高。 相似文献
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1999年台湾集集地震震后450天的GPS观测资料显示了几十到几百毫米的地表位移.下地壳的震后黏性松弛和断层无震蠕变产生的震后滑动是用来解释地表震后变形的两个主要机制.本文利用接触问题的黏弹性有限元(LDDA)方法,以GPS观测数据作为约束,分别考察了黏性松弛和震后滑动机制对地表震后变形的影响.计算结果表明,黏性松弛机制产生的地表位移与观测数据吻合较好,通过试错法由震后GPS观测约束得到的下地壳黏度为1017Pa·s,而上地幔黏度对计算结果影响不大.考察震后滑动机制对地表变形的影响时,在LDDA方法中结合了速率状态摩擦定律,结果显示震后滑动机制不能很好地解释震后450天的观测数据,它产生的地表变形只在震后50天内与观测大致吻合,之后位移值基本不随时间变化.这些结果有助于增进对集集地震震后变形机制的认识. 相似文献
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Karol Dawidowicz 《Studia Geophysica et Geodaetica》2018,62(1):38-56
It is well-known that the phase center of a Global Navigation Satellite System (GNSS) antenna is not a stable point coinciding with a mechanical reference. The phase center position depends on the direction of the received signal, and is antenna-and signaldependent. Phase center corrections (PCC) models of GNSS antennas have been available for several years. The first method to create antenna PCC models was the relative field calibration procedure. Currently only absolute calibration models are generally recommended for use. In this study we investigate the differences between position estimates obtained using individual and type-mean absolute antenna calibrations in order to better understand how receiver antenna calibration models contribute to the Global Positioning System (GPS) positioning error budget. The station positions were estimated with two absolute calibration models: the igs08.atx model, which contains typemean calibration results, and individual antenna calibration models. Continuous GPS observations from selected Polish European Permanent Network (EPN) stations were used for these studies. The position time series were derived from the precise point positioning (PPP) technique using the NAPEOS scientific GNSS software package. The results show that the differences in the calibrations models propagate directly into the position domain, affecting daily as well sub-daily results. In daily solutions, the position offsets, resulting from the use of individual calibrations instead of type-mean igs08.atx calibrations, can reach up to 5 mm in the Up component, while in the horizontal one they generally stay below 1 mm. It was found that increasing the frequency of sub-daily coordinate solutions amplifies the effects of type-mean vs individual PCC-dependent differences, and also gives visible periodic variations in time series of GPS position differences. 相似文献
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The Pannonian Basin, which includes Hungary, tectonically belongs to the Eurasian Plate and is considered to be relatively quiet. Detailed geological studies revealed four main tectonic units in this area—the Tisza, Pelso, Austro-Alpine and Vepor units. All of these can be genetically related to tectonic processes in the Mediterranean and Alpine-Adria region.In 1989 the Satellite Geodetic Observatory (SGO) in cooperation with several institutions has initiated the establishment of a geodynamic global positioning system (GPS) Reference Network (HGRN) for three-dimensional deformation studies in Hungary. The HGRN consists of 13 primary sites which were selected according to geological and geophysical considerations and satisfied international standards for tectonic studies with the GPS technique. Particular care was devoted to the point marks concerning mechanical stability and the repeatability of antenna set-ups at the HGRN sites, therefore a point mark and a mechanical adapter to mount the GPS antenna had been developed at the SGO for this purpose. This point mark has been used at all HGRN sites. A GPS Datum Point was also established for Hungary in 1990 at the Satellite Geodetic Observatory; here quasi continuous observations are foreseen. The Penc station has been accepted as a fiducial station of the International GPS Geodynamic Service (IGS).The zero epoch measurements were completed in fall 1991 and monitoring is planned every second year at least for the next 10 years.Preliminary processing of the data has been carried out in the SGO, Penc and at the Lustbühel Observatory at Graz, using the TRIMVEC PLUS and BERNESE V3.2 programs respectively 相似文献
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Very short baseline interferometry: assessment of the relative stability of the GPS stations at the Yebes Observatory (Spain) 总被引：1，自引：0，他引：1
Alvaro Santamaría-Gómez 《Studia Geophysica et Geodaetica》2013,57(2):233-252
Using a very short baseline interferometer, the relative stability of the YEBE and YEB1 GPS stations at the Yebes Observatory (Spain) is assessed. A baseline length bias of 1 mm was found between estimates from different observed frequencies due most likely to phase center errors resulting from antenna calibration uncertainties and/or phase center migrations caused by the electromagnetic coupling of antenna and monument. Also a bias of 0.5 mm in the vertical component of the baseline length was found between estimates from different cut-off elevation angles due to elevation-dependent errors as phase center and multipath. In addition to these biases, significant variations in the horizontal component of the baseline length were found, mostly in the form of a trend of ?0.45 ± 0.10 mm/yr and an annual oscillation of amplitude 1 ± 0.1 mm and phase 155 ± 5 (beginning of June). The annual oscillation showed a high correlation with ambient temperature variations. Bedrock thermal expansion seems not to be a significant contributor to the annual variation due to the excellent agreement between the phases of the baseline and temperature annual signals. Thermoelastic expansion of the station monuments, which are comprised of concrete pillars and buildings, driven by the sunshine heating, is likely the origin of this oscillation. Near-field multipath and phase center errors are also rejected as being the main contributor to the annual signal. Conversely, near-field multipath and phase center errors may significantly contribute together to the time-correlated noise content of the baseline time series at long periods (flicker noise amplitude of 1.2 ± 0.1 mm). This research provides thus an assessment of the GPS station stability at the Yebes Observatory, which may be extended to the level of station-dependent contamination of geophysical and geodetic studies (e.g., plate tectonics, surface loadings, local ties) when similar station installations on top of buildings are used. 相似文献
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北京地区区域性形变场与近期强震危险性研究 总被引：3，自引：0，他引：3
分析1998－2000年期间水准和GPS测量给出的北京地区区域性形变场的背景值及其与定点断层形变观测值的关系。结果表明：（1）该地区的大面积垂直形变速率及速率梯度值在华北地区的通常 数值之下，也低于若干大地震前的相应异常特征值；（2）该区由GPS方法显示的大面积水平形变速率也属于较低水平；（3）定点观测的断层形变速率（垂直向和水平向）与区域性的背景值相当；（4）根据大面积形变场的 断层形变异常水平，预计近期（1－3年内）北京地区不会发生较强地震。 相似文献
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地表温度变化可以引起GPS台站上安装GPS天线的地表水泥墩内部温度变化,还可以通过热传导的方式引起GPS台站基岩温度变化,从而引起GPS台站垂直位移变化.在中国区域,由GPS台站基岩温度变化引起GPS台站垂直位移变化的周年振幅最大可以达到1 mm;在长江以北地区,此周年振幅一般大于0.5 mm.在我国地壳运动观测网络中的23个GPS基准站中,温度变化对GPS台站垂直位移总影响的周年振幅最大值为2.8 mm,其中13个GPS基准站垂直位移的周年振幅变化大于1 mm.因此,温度变化是引起GPS台站垂直位移周年变化的一个不可忽视因素. 相似文献
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在海上实施三维地震探测过程中,人工震源枪阵中心与船上GPS的距离及地震探测作业中的船行方向造成炮点实际位置与预设位置有一定偏差;自由落体投放的OBS由于海流的影响会偏离原定设计位置(投放点),因此,炮点与海底地震仪(OBS)的位置校正是三维地震结构研究中的基本环节.本文利用艏向信息校正了炮点位置;采用蒙特卡洛和最小二乘法方法对海底地震仪的位置进行了校正,并探讨了直达水波曲线特征.结果表明 OBS位置一般偏离设计点1 km左右,其误差范围在20 m以内,校正后的OBS记录剖面展示了真实的记录情况.该研究结果为下一步西南印度洋的三维层析成像研究提供了坚实数据基础,同时为今后南海的三维深部地壳结构探测提供经验与借鉴. 相似文献