Altimeter's Capability of Reconstructing Realistic Eddy Fields Using Space-Time Optimum Interpolation     

Tsurane Kuragano  Masafumi Kamachi 《Journal of Oceanography》2003,59(6):765-781

Sea surface height anomaly maps of realistic eddy activity were obtained by applying space-time optimum interpolation to altimeter data. Analysis error and rate of reconstructing eddy signals were investigated by taking account of: 1) dependency on orbit configurations of single and multiple altimeters; 2) dependency on space-time scales of realistic, dominant eddies; and 3) effect of space-time scales of eddy propagation. Large-scale sea surface height anomalies are subtracted from altimeter data by applying an along-track filter to allow easy handling of eddy signals. The space-time scales of the first-guess error in the optimum interpolation are statistically evaluated by fitting a space-time anisotropic Gaussian function to space-time-distributed correlation coefficients of sea surface height using the TOPEX data. The results of the optimum interpolation clarify the followings: 1) ERS has a better capability of reconstructing eddy signals than TOPEX. Comparison of maps from multi-altimeter data shows that TOPEX+ERS has a better capability than Jason−1+TOPEX in lower latitudes and vice versa in higher latitudes, though the differences are small. 2) The small space-time scale yields a low reconstruction rate in marginal seas and alongside the equator. The persistent timescale is large, and westward propagation is dominant in the subtropical and subarctic regions, where the reconstruction rates are high. 3) The optimum interpolation, taking account of eddy propagation, provides higher reconstruction rates than that taking no account of the propagation. The effect of propagation on the optimum interpolation is greater when it is applied to single-altimeter data than to multi-altimeter data. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

ERP预报误差对低轨卫星精密轨道预报的影响     

张欣欣  王磊  许钡榛  李涛  陈锐志 《大地测量与地球动力学》2020,40(5):482-485

结合珞珈一号卫星轨道数据,分析地球自转参数（ERP）预报误差对低轨卫星精密轨道预报的影响。结果表明,ERP预报误差主要对轨道切向和法向产生影响,对径向影响较小。当预报时间为10 d时,切向误差可达到dm级,这对cm级定位会产生较大影响。  相似文献   

北斗三号全球系统空间信号精度评估分析     

许扬胤  杨元喜  曾安敏  马越原 《大地测量与地球动力学》2020,40(10):1000-1006

以精密星历和钟差为基准,对BDS-3广播星历的轨道精度、钟差精度和3类空间信号测距误差(signal-in-space range error, SISRE)精度进行评估。结果表明,BDS-3广播星历的轨道精度明显优于BDS-2同类卫星,其轨道径向RMS精度优于0.18 m,切向和法向RMS精度优于0.6 m;BDS-3广播星历钟差的误差基本小于5 ns,且较BDS-2卫星变化更为平稳,其平均RMS统计精度为1.86 ns,平均95%统计精度为3.23 ns,均优于BDS-2卫星;BDS-3卫星仅受轨道影响的SISRE、全球平均SISRE和最差SISRE的RMS统计精度分别为0.12 m、0.58 m和0.60 m,相应95%统计精度分别为0.22 m、0.99 m和1.02 m,较BDS-2均有明显提升。  相似文献   

北斗卫星多天轨道合成方法及其精度分析     

刘伟平  郝金明  于合理  田英国 《测绘学报》2016,45(10):1157-1164

目前,北斗卫星多天解轨道主要是通过常规的数据累积解算获得,处理效率较低。此外,由于开通运行不久,北斗卫星力学模型尚未完善,限制了多天解轨道精度的进一步提高。针对以上问题,本文提出了附加伪随机脉冲的北斗卫星多天轨道合成方法,利用法方程叠加实现北斗卫星多天轨道合成,可有效提高轨道解算效率。同时,利用伪随机脉冲对力学模型的补偿作用,进一步提高了多天轨道合成的精度水平。实测数据分析表明:在多天轨道合成中,单天边界附加伪随机脉冲对北斗卫星轨道精度有明显改进作用。其中,3类卫星切向、法向轨道精度的改善程度大于径向,GEO和IGSO卫星轨道精度的提高幅度大于MEO卫星。一定范围内,随着定轨弧段的增长,北斗卫星定轨精度能够得到不同程度的改善,且主要表现在轨道切向。  相似文献   

LEO卫星单频精密定轨电离层模型改进算法   总被引：1，自引：1，他引：0  

田英国  郝金明  于合理  刘伟平  谢建涛  张康 《测绘学报》2016,45(7):803-809

电离层延迟的有效改正是LEO卫星单频精密定轨的关键所在。目前主要采用电离层比例因子法进行LEO卫星电离层延迟改正,但该方法在电子密度峰值高度确定时未考虑太阳活动、经纬度、昼夜变化、季节等因素的影响。IRI2012模型虽然考虑了上述因素对电子密度峰值高度的影响,但因其与电离层薄层高度选择的标准不一致,通常它们之间存在系统性偏差而无法直接使用。为此本文提出将电离层薄层高度作为约束条件对IRI2012模型确定的电子密度峰值高度的均值进行参数约束估计,得到一种改进的电离层模型算法,并利用Swarm卫星GPS观测数据对其进行验证。结果表明:改进的电离层模型对Swarm卫星径向、切向和法向定轨精度均有不同程度的提高,尤其对轨道径向和法向精度改善最为明显,分别提高了31.6%和32.0%;同时较大幅度地降低了轨道的系统性偏差,尤其是在径向和法向,分别平均降低了65.0%和54.7%。  相似文献   

不同型号卫星的光压模型参数的拟合     

刘永  李姗姗  张传定  王琰 《测绘科学技术学报》2016,(1):33-37

随着GPS卫星型号的不断更新,目前共存在8种型号的卫星。每一种型号卫星的材质不尽相同,关于卫星的光压模型也略微不同。探究了不同型号卫星在body-fixed坐标系下光压加速度分量关于B角的约函数模型;利用IGS提供的精密星历,通过动力学轨道平滑过程来拟合8 d的数据,生成在solar-oriented坐标系下的加速度;把加速度在solar-oriented坐标系D-Y-B轴的分量转换到在body-fixed坐标系X-Y-Z轴分量;利用最小二乘法则拟合关于B角的约函数模型,建立关于B角的不同型号卫星的傅里叶光压模型,并进行轨道的外推。通过分析轨道外推的精度,验证GPS不同型号卫星光压模型拟合的精准性,为以后北斗卫星的光压建模提供理论依据。  相似文献   

一种快速的集中式自主定轨新算法     

谢金石 《测绘科学技术学报》2016,(5)

针对导航星座自主定轨,提出一种提高集中式算法效率的新思路,即充分利用高频、高精度的星间链路测距信息,在短弧内将卫星最优轨道与长期预报轨道的差异用多次曲线描述,得到卫星位置和速度的最佳估值。此方法无需动力学建模和计算状态转移矩阵,因此算法极为简洁。同时,对于自主运行期间缺乏空间基准,提出约束轨道升交点赤经的方法,以减小对地面系统的依赖程度。仿真结果表明,导航星座自主运行60 d,不考虑地球自转参数(EOP)长期预报误差,在无锚固站的情况下,链路数不少于5条时能够达到轨道URE优于1 m,位置3 m,速度毫米级的定轨精度。最后,通过比对验证了新算法比已有EKF分布式自主定轨算法的效率更高。  相似文献   

晨昏轨道微波温度计资料同化对降水定量预报的影响及其对三轨卫星系统的意义     

邹晓蕾  秦正坤  翁富忠 《大气科学》2016,40(1):46-62

极轨卫星的高级微波温度计(Advanced Microwave Sounding Unit-A,简称AMSU-A)辐射资料对提高降水定量预报的水平有重要作用.但是极轨卫星的轨道特征导致乘载其上的微波温度计资料在区域同化系统中存在严重缺测.本研究重点分析了晨昏轨道卫星上微波温度计资料同化对墨西哥湾沿岸定量降水预报的重要影响.研究选取了早晨星NOAA-15、上午星MetOp-A和下午星NOAA-18,利用美国NCEP(National Centers for Environmental Prediction)的业务同化系GSI(Gridpoint Statistical Interpolation)资料同化系统,进行了加和不加NOAA-15 AMSU-A资料的两组资料同化和预报试验,来阐明晨昏轨道卫星上微波温度计资料同化对墨西哥湾沿岸降水预报的重要影响.试验结果分析表明如果仅同化NOAA-18和MetOp-A资料,在协调世界时00:00和12:00的同化时间,在墨西哥湾和美国西部大陆就是卫星观测资料缺测区,而早晨星NOAA-15资料正好可以填补这个资料空缺.模式预报也表明,同化NOAA-15的AMSU-A资料可以对墨西哥湾降水有持续的正影响.这一研究证明了保持有搭载着AMSU-A或者相似仪器的早晨星,对区域降水预报的重要性.由于目前NOAA-15是唯一的一颗正在运行的、已远超过其正常运行期的早晨星,通过技术手段维持NOAA-15的AMSU-A仪器更超长期运行也就特别重要.  相似文献   

航天器轨道向导式设计器的设计与实现     

龚志辉  姜挺  江刚武 《测绘学院学报》2006,(2)

航天器轨道设计因卫星应用目的和总体设计方案的不同而灵活多样。文中在对航天器轨道设计方法归纳总结的基础上,采用组件方式设计了向导式轨道设计器。该设计器能够实现太阳同步轨道等典型轨道的初始轨道设计任务,通过与卫星工具软件(STK)设计结果的比较,验证了设计器的正确性。  相似文献   

Pseudo-Stochastic Orbit Modeling Techniques for Low-Earth Orbiters     

A. Jäggi  U. Hugentobler  G. Beutler 《Journal of Geodesy》2006,80(1):47-60

The Earth’s non-spherical mass distribution and atmospheric drag cause the strongest perturbations on very low-Earth orbiting satellites (LEOs). Models of gravitational and non-gravitational accelerations are utilized in dynamic precise orbit determination (POD) with GPS data, but it is also possible to derive LEO positions based on GPS precise point positioning without dynamical information. We use the reduced-dynamic technique for LEO POD, which combines the geometric strength of the GPS observations with the force models, and investigate the performance of different pseudo-stochastic orbit parametrizations, such as instantaneous velocity changes (pulses), piecewise constant accelerations, and continuous piecewise linear accelerations. The estimation of such empirical orbit parameters in a standard least-squares adjustment process of GPS observations, together with other relevant parameters, strives for the highest precision in the computation of LEO trajectories. We used the procedures for the CHAMP satellite and found that the orbits may be validated by means of independent SLR measurements at the level of 3.2 cm RMS. Validations with independent accelerometer data revealed correlations at the level of 95% in the along-track direction. As expected, the empirical parameters compensate to a certain extent for deficiencies in the dynamic models. We analyzed the capability of pseudo-stochastic parameters for deriving information about the mismodeled part of the force field and found evidence that the resulting orbits may be used to recover force field parameters, if the number of pseudo-stochastic parameters is large enough. Results based on simulations showed a significantly better performance of acceleration-based orbits for gravity field recovery than for pulse-based orbits, with a quality comparable to a direct estimation if unconstrained accelerations are set up every 30 s.  相似文献