卫星激光测距技术滤波方法的研究与实现

本文从激光测距回波方程及噪声方程出发阐明了降低背景噪声(滤波)是提高激光测距回波信噪比的关键;并通过对望远镜轴系进行指向修正并采用可变光阑减小望远镜视场来实现"空间滤波",采用窄带滤光片实现"光谱滤波",采用高精度距离门选通技术实现"时间滤波",北京房山人卫观测站的激光测距系统具备了白天观测人造地球卫星的能力。本文还引入了C-SPAD"敏感度"的概念并且提出了一种依靠C-SPAD来调整可变光阑位置及滤光片角度的方法。     

人卫激光测距望远镜系统的指向修正

利用实测数据分析了人卫激光测距望远镜系统常用的两种指向修正模型(球谐函数模型与Mount Strom lo支架模型)的精度和稳定性。结果表明,两种模型均能达到较好的拟合精度,但Mount Strom lo支架模型系数间大多不相关,其稳定性明显优于球谐函数模型。     

北京人卫激光观测站kHz激光测距系统升级实现

本文介绍了北京人卫激光观测站的kHz激光测距系统的改造与实现情况,并对kHz卫星激光测距系统的实测结果进行了简析,比较了不同激光发生器的测距激光。研究结果表明,该站的kHz卫星激光测距系统已经初步实现,且观测数据量和观测精度较以往低重复频率激光发生器都有所改善。     

北京人卫激光观测站白天激光测距实现

对于卫星激光测距来说, 白天测距是当今卫星激光测距领域的主要研究和发展方向。北京卫星观测站是在千赫兹激光测距的基础上实现的白天激光测距。本文介绍了北京卫星观测站白天激光测距系统实现方法, 并对观测结果进行了计算和分析,得出了北京人卫激光观测站在白天卫星激光接收系统性能提高的基础上观测数据的数量和质量不断提高的结论。     

基于地靶的卫星激光观测数据分析

地靶测量是卫星激光测距中的重要组成部分。本文首先简要介绍了卫星激光测距及其地靶测量的基本原理,其次对北京房山人卫激光站2006-2007年地靶观测数据进行处理和分析。研究结果表明,近两年来房山人卫激光站通过硬件和软件的改善,其观测系统的性能有所提高。     

人卫激光测距资料的压缩处理和统计分析

本文主要介绍由人卫激光测距的完整原始资料压缩生成标准点的过程，同时也对各个测站的观测资料按月进行了统计分析和精度估计。为了消除长弧解中非模型摄动所引起的系统差，我们应用了短弧和长弧定轨相结合的方法，进一步提高了解算精度。     

获取高质量激光观测数据方法

对长期人卫激光测距的实践工作的总结,并经过对实际观测结果的分析和对比,得出的正确获得卫星观测数据要求和方法,以此说明如何才能更好的收到每一卫星通过和合格数据     

佘山13m口径射电望远镜指向扫描数据解析

佘山13 m射电望远镜作为新一代天体测量与空间大地测量甚长基线干涉测量系统,配备有2～14GHz宽频接收机和X/Ka双频接收机。指向精度是射电望远镜性能的重要指标之一,一般要求好于最高配置频率波束宽度的1/10。对于佘山13 m口径射电望远镜,Ka波段32 GHz时的指向精度约为18 as。基于该望远镜的指向扫描实测数据,探讨了指向改正模型建立方法,包括测量功率曲线拟合、积分时间影响分析、指向改正模型参数设置等,实测评估了该望远镜的指向精度。所得指向改正模型可作为系统调试与改进的依据,也是望远镜系统指标测量和观测目标精确跟踪的保障,数据解析模型与分析流程可用于测量系统的日常指向精度检核,也可供类似工程测量参考。     

武汉人卫站第三代卫星激光测距系统

本文阐述武汉人卫站第三代卫星激光测距系统，包括硬件和软件，并介绍了１９９０年和１９９年的观测情况。从两年多的观测实践和国外返馈的结果可知：①武汉站第三代卫星激光测距系统能够观测所有带反射镜的激光卫星，具有一定的地影观测能力，单次测距精度为２－４ｃｍ；②实现了用微机进行实时跟踪控制；③研制的软件系统可以提高卫星位置预报精度、增强信噪分辨力、以及提高资料利用率。     

激光测卫与测月的现状及发展趋势

现在,激光测卫与测月已达到进行地球动力学研究所需的精度。本文从激光测距系统的主要硬部件、环境影响对测距精度的限制以及数据处理等方面,论述激光测距的现状及发展趋势。     

天球参考系的基本理论和方法研究进展

天球参考系的研究在天体测量、大地测量等研究领域中占有重要的地位。随着配置有CCD的地面光学望远镜和空间望远镜观测精度的不断提高 ,以及其它空间大地测量技术 (VLBI、LLR、SLR和GPS等 )的发展 ,对天球参考系也提出了越来越高的要求。本文从天球参考系的基本理论和方法出发 ,详细地介绍了天球参考系目前的发展状况 ,指出乌克兰里克米亚天文台、上海天文台和IERS在计算河外射电源参考架时采用的小角旋转法公式是错误的 ,并进行了改正     

利用SLR数据进行广播星历精度评估

论述了利用SLR观测数据进行广播星历精度评估的原理、方法及计算模型。通过理论分析及对比试算,得出该方法所能达到的精度为0.03 m,与微波观测数据计算结果存在近50 mm的系统差,验证了方法的可行性。该方法为广播星历精度评估提供了独立的外部检核条件,克服了利用精密星历评估必须事后进行的缺点,达到了实时处理的效果。采用2005年SLR观测数据对GPS 35卫星广播星历精度进行了实测数据评估,给出了有益的结论。     

利用SLR数据进行广播星历精度评估

论述了利用SLR观测数据进行广播星历精度评估的原理、方法及计算模型.通过理论分析及对比试算,得出该方法所能达到的精度为0.03 m,与微波观测数据计算结果存在近50 mm的系统差,验证了方法的可行性.该方法为广播星历精度评估提供了独立的外部检核条件,克服了利用精密星历评估必须事后进行的缺点,达到了实时处理的效果.采用2005年SLR观测数据对GPS 35卫星广播星历精度进行了实测数据评估,给出了有益的结论.     

Surveying co-located space-geodetic instruments for ITRF computation

A new and comprehensive method is presented that can be used for estimating eccentricity vectors between global positioning system (GPS) antennas, doppler orbitography and radiopositioning integrated by satellites (DORIS) antennas, azimuth-elevation (AZ-EL) very long baseline interferometry (VLBI) telescopes, and satellite laser ranging (SLR) and lunar laser ranging (LLR) telescopes. The problem of reference point (RP) definition for these space-geodetic instruments is addressed and computed using terrestrial triangulation and electronic distance measurement (EDM) trilateration. The practical ground operations, the surveying approach and the terrestrial data processing are briefly illustrated, and the post-processing procedure is discussed. It is a geometrically based analytical approach that allows computation of RPs along with a rigorous statistical treatment of measurements. The tight connection between the geometrical model and the surveying procedure is emphasized. The computation of the eccentricity vector and the associated variance–covariance matrix between an AZ-EL VLBI telescope (with or without intersecting axes) and a GPS choke ring antenna is concentrated upon, since these are fundamental for computing the International Terrestrial Reference Frame (ITRF). An extension to RP computation and eccentricity vectors involving DORIS, SLR and LLR techniques is also presented. Numerical examples of the quality that can be reached using the authors approach are given. Working data sets were acquired in the years 2001 and 2002 at the radioastronomical observatory of Medicina (Italy), and have been used to estimate two VLBI-GPS eccentricity vectors and the corresponding SINEX files.     

自适应Lp估计及其在SLR数据预处理中的应用

本文简要介绍了自适应Ｌｐ估计的有关理论和求解方法，并对ＳＬＲ数据的测量误差作了统计分析。发现ＳＬＲ数据的测量误差服从ｐ值不定的ｐ范分布。本文ＳＬＲ数据预处理实例表明自适应Ｌｐ估计能给出比ＬＳ估计更为稳健有效的拟合参数。当观测值粗差高达６６％时，自适应Ｌｐ估计仍能给出可靠的拟合参数，效果明显优于传统的ＬＳ估计。     

Combination of GNSS and SLR observations using satellite co-locations

Satellite Laser Ranging (SLR) observations to Global Navigation Satellite System (GNSS) satellites may be used for several purposes. On one hand, the range measurement may be used as an independent validation for satellite orbits derived solely from GNSS microwave observations. On the other hand, both observation types may be analyzed together to generate a combined orbit. The latter procedure implies that one common set of orbit parameters is estimated from GNSS and SLR data. We performed such a combined processing of GNSS and SLR using the data of the year 2008. During this period, two GPS and four GLONASS satellites could be used as satellite co-locations. We focus on the general procedure for this type of combined processing and the impact on the terrestrial reference frame (including scale and geocenter), the GNSS satellite antenna offsets (SAO) and the SLR range biases. We show that the combination using only satellite co-locations as connection between GNSS and SLR is possible and allows the estimation of SLR station coordinates at the level of 1–2 cm. The SLR observations to GNSS satellites provide the scale allowing the estimation of GNSS SAO without relying on the scale of any a priori terrestrial reference frame. We show that the necessity to estimate SLR range biases does not prohibit the estimation of GNSS SAO. A good distribution of SLR observations allows a common estimation of the two parameter types. The estimated corrections for the GNSS SAO are 119 mm and −13 mm on average for the GPS and GLONASS satellites, respectively. The resulting SLR range biases suggest that it might be sufficient to estimate one parameter per station representing a range bias common to all GNSS satellites. The estimated biases are in the range of a few centimeters up to 5 cm. Scale differences of 0.9 ppb are seen between GNSS and SLR.     

地心非旋转坐标系中伪距与激光测距法时间比对计算模型

分析了伪距与激光测距法时间比对的基本原理,分别从数学和几何角度详细推导了地心非旋转坐标系中伪距与激光测距法时间比对的基本计算模型,这对于实现星地之间高精度的时间同步具有重要意义.     

Atmospheric range correction for two-frequency SLR measurements

It has been widely known that the use of two-frequency Satellite Laser Ranging (SLR) system is limited by stringent precision requirements of the range measurements and the proper atmospheric model. Owing to the stringent requirements, this SLR system is impractical for the current requirement of SLR measurements within the framework of global geodetic observing system (GGOS). If in the future this stringent requirement could be met, this SLR system would be an attractive tool to reduce atmospheric propagation effects of SLR and would be of great benefit for the next generation of GGOS design. To anticipate possible future developments of the two-frequency SLR systems, we have developed a new atmospheric correction formula for the two-frequency SLR measurements. The new formula eliminates the total atmospheric density effect including its gradient and provides two terms to calculate the curvature effect and the water vapor distribution effect. While the curvature effect can be calculated by an accurate model, the required information about the water vapor distribution along the propagation path can be calculated using previous developments of optical delay modeling or alternatively using results from microwave measurements. Theoretical simulations using the two-frequency systems of the Graz and TIGO-Concepción stations shows that the new formula completely reduces all propagation effects at any elevation angle above 3° with an accuracy better than 1 mm. However, the required precision for the difference of the two-frequency SLR measurements, i.e. better than 45 μm for a single epoch, exceeds the capability of the current state of the art SLR systems.     

基于精密星历的北斗卫星广播星历精度分析

卫星广播星历的精度直接决定用户导航定位的精度。它既是实时用户关心的问题,也是系统建设者检验系统服务水平的重要指标。本文介绍了事后精密星历和卫星激光测距观测量评估广播星历精度的原理和方法,采用事后精密星历评估广播星历的精度,利用激光测距观测量进行精度检核。分析表明：北斗卫星广播星历的视向距离误差优于1m．     

利用SLR及伪距数据进行卫星预报钟差精度验证

论述了综合利用SLR和伪距观测数据进行导航卫星预报钟差精度评估的原理及计算步骤。分析了该方法所能达到的精度，并进行了可行性验证。采用2005年的观测数据对广播星历预报钟差精度进行了评估，给出了有益的结论。