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1.
全球定位系统(Global Positioning System,简称GPS)是美国从20世纪70年代开始研制的用于军事部门的新一代卫星导航与定位系统,历时20年,耗资200多亿美元,分三阶段研制,陆续投入使用,并于1994年全面建成.GPS是以卫星为基础的无线电卫星导航定位系统,它具有全能性、全球性、全天候、连续性和实时性的精密三维导航与定位功能.而且具有良好的抗干扰性和保密性.因此,GPS技术率先在大地测量、工程测量、航空摄影测量、海洋测量、城市测量等测绘领域得到了应用. 相似文献
2.
The development of relatively inexpensive satellite receivers in the early 1970's has resulted in cost-effective applications
of satellites for a variety of geodetic surveying needs. Currently achievable accuracies range from 10 to 20 centimeters.
The NAVSTAR Global Positioning System, now under development by the Department of Defense, incorporates advanced technology
which has the potential capability of revolutionizing satellite geodesy.
Several concepts for utilizing GPS signals are briefly reviewed, and another concept, called the reconstructed carrier phase
method, is described in some detail. This concept is being pursued by the Defense Mapping Agency, National Oceanic and Atmospheric
Administration, and the U.S. Geological Survey. These agencies have numerous requirements for accurate positioning. Several
prototype receivers are planned to be available for testing in mid-1982. These receivers should be highly portable, consume
little power, and obtain base line accuracies of several centimeters in several hours of observation time. However, water
vapor radiometers will be needed in order to achieve the full accuracy. Initial simulation results utilizing the reconstructed
carrier phase method are included. 相似文献
3.
随着北斗卫星导航系统的逐渐完善,有关北斗系统定位的研究越来越深入,为了对比分析北斗系统和全球定位导航系统(GPS)定位的差异性,充分利用北斗地球静止轨道卫星(GEO)和倾斜地球同步轨道卫星(IGSO)高轨道卫星的特殊性,本文提出一种新的组合选星方法,选取卫星数较少且Position Dilution of Precision(PDOP)最小的北斗/GPS组合,分别对比分析北斗系统、GPS系统及其组合系统在楼顶开放环境和楼间恶劣环境下的定位效果。实验结果表明:北斗比GPS有更加稳定的定位效果,依据本文组合选星方法,利用少量卫星即可获得较好的定位精度。 相似文献
4.
Broadcast vs. precise GPS ephemerides: a historical perspective 总被引：6，自引：2，他引：4
The Navstar Global Positioning System (GPS) Operational Control Segment (OCS) generates predicted satellite ephemerides and clock corrections that are broadcast in the navigation message and used by receivers to estimate real-time satellite position and clock corrections for use in navigation solutions. Any errors in these ephemerides will directly impact the accuracy of GPS based positioning. This paper compares the satellite position computed using broadcast ephemeredes with the precise position provided by the International GPS Service for Geodynamics (IGS) Final Orbit solution. Similar comparisons have been undertaken in the past, but for only short periods of time. This paper presents an analysis of the GPS broadcast ephemeris position error on a daily basis over the entire operational lifetime of the GPS system. The comparison was undertaken from 14 November 1993 through to 31 December 2002. The statistics of these errors were also analyzed.Disclaimer: The views expressed in this article are those of the authors and do not reflect the official policy or position of the Royal Australian Air Force, Australian Defense Organization, Australian government, United States Air Force, US Department of Defense, or the US Government. 相似文献
5.
A global weather analysis-forecast system is used to produce six hourly analysis of meteorological fields at roughly 150 km × 150 km resolution at the National Center for Medium Range Weather Forecast (NCMRWF). In this paper, we have studied the Total Precipitable Water Content (TPWC) and Cloud Liquid Water Path (CLWP) derived from the Indian Remote Sensing (IRS-P4) Satellite over the Indian Ocean region in relation to operational numerical weather prediction (NWP) model analysis and short-range forecasts. An objective analysis was carried out by introducing the observations of CLWP, TPWC and their values (six hour forecasts) from the T80 model as the first guess, for a 20 days period of August 1999 using the standard Cressman’s technique. The reanalysis could capture the signature of TPWC and CLWP data from IRS-P4 satellite. In general the observed values of TPWC and CLWP from IRS-P4 have a positive bias compared to NCMRWF analysis over the region where the satellite passed. The CLWP values have been compared with Special Sensor Microwave/Imager (SSM/I) products from the Defense Meteorological Satellite Program (DMSP) satellites. Results indicate that the model derived CLWP values were within acceptable limits, whereas the observations from the Multi-channel Scanning Microwave Radiometer (MSMR) showed slightly larger values. 相似文献
6.
For ages, links between environment, climate and their impacts on human health have been observed and studied. Research to improve our understanding of environmental key determinants of infectious diseases can provide innovative information for adaptation strategies and lead to new tools optimizing surveillance, vector control measures, and disease prevention. As earth observation satellites can measure meteorological and environmental parameters, NASA and CNES have separately engaged in an innovative use of their earth observation infrastructure development programs: space tools addressing public health. As NASA and CNES have fruitful cooperation for satellite development missions for years, both health programs have proposed to explore a new area of collaboration: satellites addressing health issues. As members of international organizations, NASA and CNES could promote their common views towards the Group on Earth Observations (GEO) Community of Practice for Health & Environment and the Committee on Earth Observation Satellites (CEOS) Societal Benefit Area on Health. 相似文献
7.
Lucia Plank Andreas Hellerschmied Jamie McCallum Johannes Böhm Jim Lovell 《Journal of Geodesy》2017,91(7):867-880
The possibility of observing satellites with the very long baseline interferometry (VLBI) technique has been discussed for several years in the geodetic community, with observations of either existing satellites of the global navigation satellite systems or of satellites dedicated to realise a space tie. Such observations were carried out using the Australian telescopes in Hobart and Ceduna which, for the first time, integrated all the necessary steps: planning the observations (automated scheduling), correlation of the data and the generation of a series of time delay observables suitable for a subsequent geodetic analysis. We report on the development of new and the adaptation of existing routines for observing and data processing, focusing on technology development. The aim was to use methods that are routinely used in geodetic VLBI. A series of test experiments of up to six hours duration was performed, allowing to improve the observations from session to session and revealing new problems still to be solved. The newly developed procedures and programs now enable more observations. Further development assumed, this bears the prospect of being directly applied to the observation of dedicated space-tie satellites. 相似文献
8.
Improved antenna phase center models for GLONASS 总被引：6，自引：2，他引：4
Rolf Dach Ralf Schmid Martin Schmitz Daniela Thaller Stefan Schaer Simon Lutz Peter Steigenberger Gerhard Wübbena Gerhard Beutler 《GPS Solutions》2011,15(1):49-65
Thanks to the increasing number of active GLONASS satellites and the increasing number of multi-GNSS tracking stations in
the network of the International GNSS Service (IGS), the quality of the GLONASS orbits has become significantly better over
the last few years. By the end of 2008, the orbit RMS error had reached a level of 3–4 cm. Nevertheless, the strategy to process
GLONASS observations still has deficiencies: one simplification, as applied within the IGS today, is the use of phase center
models for receiver antennas for the GLONASS observations, which were derived from GPS measurements only, by ignoring the
different frequency range. Geo++ GmbH calibrates GNSS receiver antennas using a robot in the field. This procedure yields
now separate corrections for the receiver antenna phase centers for each navigation satellite system, provided its constellation
is sufficiently populated. With a limited set of GLONASS calibrations, it is possible to assess the impact of GNSS-specific
receiver antenna corrections that are ignored within the IGS so far. The antenna phase center model for the GLONASS satellites
was derived in early 2006, when the multi-GNSS tracking network of the IGS was much sparser than it is today. Furthermore,
many satellites of the constellation at that time have in the meantime been replaced by the latest generation of GLONASS-M
satellites. For that reason, this paper also provides an update and extension of the presently used correction tables for
the GLONASS satellite antenna phase centers for the current constellation of GLONASS satellites. The updated GLONASS antenna
phase center model helps to improve the orbit quality. 相似文献
9.
北斗卫星导航系统新一代试验卫星星座由2颗高轨倾斜地球同步轨道卫星（IGSO）和3颗中轨地球轨道卫星(MEO)组成,2016年2月全部发射入轨,其任务是验证北斗系统从目前区域导航定位授时服务走向全球服务的新技术体制设计及指标性能。导航卫星星载原子钟是最重要载荷之一,负责星上时间频率基准信号维持和产生。本文利用星地双向时频传递设备观测的星地钟差数据,评估了试验星配置的新型高精度铷钟和被动型氢钟的实际性能,定量比较了相对于北斗区域系统卫星钟的性能提升。结果表明,新一代试验星与北斗区域系统卫星钟差预报精度相比较有较大提高,IGSO卫星短期预报误差从0.65 ns减小到0.30 ns,MEO卫星短期预报误差从0.78 ns减小到0.32 ns,IGSO／MEO卫星中期预报误差均从2.50 ns减小到约1.50 ns.时频系统是新一代试验系统地面运控的重要组成部分,负责北斗新一代试验系统时间频率信号产生和维持。本文利用试验系统与UTC(BSNC)之间的比对数据,评估了新一代试验系统时间的实际性能,定量比较了相对于北斗区域系统时间的性能提升。结果表明,新一代试验系统时间相对于北斗区域系统时间性能有较大提高,万秒稳和天稳较北斗区域系统提高约半个数量级。时频体制是新一代试验系统的重要技术体制设计之一。本文利用中心节点与末节点的双向时间测量数据,评估了新一代试验系统末节点时频信号的实际性能。结果表明,中心节点与末节点之间具有很好的一致性,时差最大为0.23 ns. 相似文献
10.
A closed-form formula for GPS GDOP computation 总被引：7，自引：2，他引：5
Shing H. Doong 《GPS Solutions》2009,13(3):183-190
Geometric dilution of precision (GDOP) is often used for selecting good satellites to meet the desired positioning precision.
An efficient closed-form formula for GDOP has been developed when exactly four satellites are used. It has been proved that
increasing the number of satellites for positioning will always reduce the GDOP. Since most GPS receivers today can receive
signals from more than four satellites, it is desirable to compute GDOP efficiently for the general case. Previous studies
have partially solved this problem with artificial neural network (ANN). Though ANN is a powerful function approximation technique,
it needs costly training and the trained model may not be applicable to data deviating too much from the training data. Using
Newton’s identities from the theory of symmetric polynomials, this paper presents a simple closed-form formula for computing
GDOP with the inputs used in previous studies. These inputs include traces of the measurement matrix and its second and third
powers, and the determinant of the matrix. 相似文献
11.
The International GLONASS Experiment 1998 (IGEX-98) was the first international tracking campaign of the Russian counterpart
to the Global Positioning System (GPS), GLONASS. Started in October 1998, the campaign was originally scheduled to last for
three months. However, the launch of additional GLONASS satellites and a widespread enthusiasm among the participants led
to an indefinite continuation of the campaign on a “best effort” basis.
At the Delft University of Technology, the data of six IGEX-98 stations have been analyzed in detail with integrity monitoring
software, developed at the Department of Mathematical Geodesy and Positioning of the University. The software aims to detect
outliers and slips in code and phase observations in real time. In addition, the software also allows the validation of the
information contained in the broadcast navigation messages.
The results of the IGEX-98 data analyses will be presented in a three-part series. In the second part, GLONASS outlier and
slips statistics will be discussed, while in the third part the anomaly detection results of the GLONASS and GPS messages
will be shown. In this first part of the series, however, the most basic of all statistics will be considered: a simple day-to-day
count of the number of GLONASS and GPS observations. Although simple, this statistic yields a surprising amount of information
both on the availability of the GLONASS satellites and on the peculiarities of some of the receiver makes participating in
the IGEX-98 campaign. ? 2000 John Wiley & Sons, Inc. 相似文献
12.
Since the beginning of the twenty-first century,several countries have made great efforts to develop space remote sensing for building a high-resolution earth observation system.Under the great attention of the government and the guidance of the major scientific and techno-logical project of the high-resolution earth observation system,China has made continuous breakthroughs and progress in high-resolution remote sensing imaging technology.The development of domestic high-resolution remote sensing satellites shows a vigorous trend,and consequently,a relatively stable and perfect high-resolution earth observation system has been formed.The development of high-resolution remote sensing satellites has greatly pro-moted and enriched modern mapping technologies and methods.In this paper,the develop-ment status,along with mapping modes and applications of China's high-resolution remote sensing satellites are reviewed,and the development trend in high-resolution earth observa-tion system for global and ground control-free mapping is discussed,providing a reference for the subsequent development of high-resolution remote sensing satellites in China. 相似文献
13.
风云气象卫星主要技术进展 总被引：1，自引：0，他引：1
近20年来,中国风云气象卫星完成了从试验应用型向业务服务型、从第一代到第二代、从单一探测到综合探测、从定性到定量的转变,实现了业务化、系列化、定量化的发展目标,风云卫星数据预处理、产品生成、数据应用技术取得全面进步。在地理定位方面,通过发展自主的地理定位算法,持续优化算法精度,业务定位精度提高到1个像素。在辐射定标方面,发展了基于月球订正的星上内黑体定标算法、深对流云定标、月亮定标和交叉定标等算法,建立了综合定标系统,太阳反射波段平均定标偏差小于5%,红外通道平均定标偏差小于0.5 K。建立了风云气象卫星产品生产及质量控制体系,具备数十种大气、陆地、海洋、空间天气定量遥感产品生产能力,部分产品质量达到或接近国际同类产品先进水平。风云气象卫星资料在天气、气候、生态、环境等领域得到广泛应用,特别是通过ECMWF(欧洲中期天气预报中心)的严格测试评估,在国际顶级数值预报模式中得到同化应用,标志着风云气象卫星部分仪器数据质量达到或接近国际先进水平。虽然中国风云气象卫星观测体系基本形成、观测精度不断提高、业务服务能力日趋增强,但仍存在仪器稳定性差、探测能力有限、探测精度有待进一步提高等问题。风云气象卫星未来发展需着重考虑以下几个方面:(1)建立合理的多星综合观测体系,重点是优化高中、低气象卫星轨道配置方案,建立多星联合组网观测体系,增强全球监测能力,提高时空分辨率;(2)提高探测精度,包括发展高精度星上定标系统,提高观测仪器的精度和稳定性,发展先进的卫星数据处理和产品反演算法等;(3)增强探测能力,重点是加强新型探测方法、探测技术研究,逐步实现对气象全要素的遥感探测,(4)增强应急响应能力,提高短时强对流等灾害天气监测能力;(5)提高卫星观测的连续性和稳定性,满足气候变化研究的需求;(6)增强多源数据综合应用能力,提高气象卫星的应用效益。 相似文献
14.
地球系统空间观测:从科学卫星到月基平台 总被引：1，自引：0，他引：1
五十多年来,全球性对地观测已形成强大的技术能力和系统体系,在不同应用领域发挥了重要作用。随着对陆地、大气、海洋研究的深入,地球系统科学和全球变化研究正在向空间对地观测技术提出新的重大战略性需求。本文描述了面向全球变化应对、发展全球变化系列科学卫星的方案;提出面向宏观地球科学现象探测、构建月基对地观测系统的设想;同时,作为宏观地球科学现象研究的一个方向,论述了利用地球科学卫星和月基对地观测技术开展全球变化"三极"对比研究的思路。 相似文献
15.
中国十分重视海洋遥感及其监测技术的发展,初步形成了具有优势互补的海洋遥感观测体系,并发挥了显著的经济和社会效益。其中,海洋一号(HY-1A/B)卫星已经广泛应用于中国海温预报业务系统、冬季海冰业务监测、夏季赤潮和绿潮监测、海岸带动态变化监测、近岸海水水质监测和渔业遥感监测等方面。海洋二号(HY-2A)卫星不仅填补了中国海洋动力环境卫星遥感的空白,也是目前国际上唯一在轨运行的集主被动微波遥感器于一身的综合型海洋动力环境卫星,具备同时获取风场、有效波高、海面高度和海面温度的能力。通过卫星获得的数据提高了中国海洋环境监测与灾害性海况预报的水平,为国民经济建设和国防建设、海洋科学研究、全球变化研究等提供了可靠的遥感数据,同时还在国际对地观测体系中发挥了重要作用,受到国内外用户的高度认可。海洋一号和海洋二号卫星系列为中国建立完善的海洋环境立体监测体系奠定了坚实基础。根据国家发展和"一带一路"建设的实施,在加快建设海洋强国、维护海洋权益和加快发展海洋经济的进程中对海洋遥感的发展也进一步提出了更高的要求和更紧迫的需求。为此,紧紧围绕国家海洋强国战略需求,在《国家民用空间基础设施中长期发展规划(2015年—2025年)》中专门规划了海洋观测卫星系列,服务于中国的海洋资源开发、环境保护、防灾减灾、权益维护、海域使用管理、海岛海岸带调查和极地大洋考察等方面,同时兼顾陆地和大气观测领域的需求。在充分继承已有HY-1A/B、HY-2A、高分三号(GF-3)和中法海洋卫星(CFOSAT)成功研制经验和应用成果的基础上,发展多种光学和微波遥感技术,建设新一代的海洋水色卫星和海洋动力环境卫星,具备卫星组网观测能力;发展海洋监视监测卫星,构建优势互补的海洋卫星综合观测体系。通过空间基础设施的建设,海洋遥感卫星必将在建设海洋强国的进程中发挥出重要作用。 相似文献
16.
Precision real-time navigation of LEO satellites using global positioning system measurements 总被引：4，自引：3，他引：1
Continued advancements in remote sensing technology along with a trend towards highly autonomous spacecraft provide a strong
motivation for accurate real-time navigation of satellites in low Earth orbit (LEO). Global Navigation Satellite System (GNSS)
sensors nowadays enable a continuous tracking and provide low-noise radiometric measurements onboard a user spacecraft. Following
the deactivation of Selective Availability a representative real-time positioning accuracy of 10 m is presently achieved by
spaceborne global positioning system (GPS) receivers on LEO satellites. This accuracy can notably be improved by use of dynamic
orbit determination techniques. Besides a filtering of measurement noise and other short-term errors, these techniques enable
the processing of ambiguous measurements such as carrier phase or code-carrier combinations. In this paper a reference algorithm
for real-time onboard orbit determination is described and tested with GPS measurements from various ongoing space missions
covering an altitude range of 400–800 km. A trade-off between modeling effort and achievable accuracy is performed, which
takes into account the limitations of available onboard processors and the restricted upload capabilities. Furthermore, the
benefits of different measurements types and the available real-time ephemeris products are assessed. Using GPS broadcast
ephemerides a real-time position accuracy of about 0.5 m (3D rms) is feasible with dual-frequency carrier phase measurements.
Slightly inferior results (0.6–1 m) are achieved with single-frequency code-carrier combinations or dual-frequency code. For
further performance improvements the use of more accurate real-time GPS ephemeris products is mandatory. By way of example,
it is shown that the TDRSS Augmentation Service for Satellites (TASS) offers the potential for 0.1–0.2 m real-time navigation
accuracies onboard LEO satellites. 相似文献
17.
The development of the analytical theory of the motion of an artificial satellite (Berger, 1972–1975) points out the great importance of the second, third order and coupling terms between zonal harmonics. These
terms have been added to the equations established byKing-Hele andCook (1968–1973) for the determination of odd zonal harmonics. This solution is compared with theirs. It satisfies all the equations
much better and especially the equations relating to near-critical inclination satellites. 相似文献
18.
全球导航卫星系统的进展及建设CORS的思考 总被引：10，自引：2，他引：8
介绍了GPS和GLONASS全球导航卫星系统的新进展，对GPS现代化的三个步骤作了简要介绍，对它和GLONASS的技术差异作了简评，对Galileo和北斗导航卫星系统的前景作了讨论。指出导航卫星系统将进入一个多系统近百颗卫星同时并存的新局面，用户将面临多系统导航卫星信号使用方面的组合、选用和最优化问题。讨论了全球导航卫星连续运行站网及其服务系统的构成和作用，及其在国内各地区各系统建设的概况。指出当前缺乏在国家级层面对全球导航卫星地面连续运行站系统的统一规划、设计、规范和标准。建议明确全球导航卫星系统的建设和管理的政府主管部门，建立全球导航卫星的国家级地面连续运行站系统，制定全球导航卫星地面连续运行站系统的国家级技术规范和标准，包括它的服务功能。 相似文献
19.
R. J. Anderle 《Journal of Geodesy》1979,53(2):109-116
A dual frequency Doppler receiver is being developed by the Naval Surface Weapons Center for possible use by the Defense Mapping
Agency in determining the position of ground sites based on observations of NAVSTAR Global Positioning satellites. Preliminary
analysis indicates that the relative position of widely separated sites can be computed to better than 40 cm accuracy at eight
hour intervals. A number of possibilities are being explored to improve the accuracy to the sub-decimeter level. 相似文献
20.
我国陆地卫星的快速发展和人工智能等高新技术的广泛应用为重构卫星遥感监测体系奠定了重要基础。针对我国自然资源保护、国土空间规划实施监督、生态修复及全球变化研究等对土地利用、土地覆盖及其相关地表参数指标动态变化信息的需求,基于当前我国陆地卫星观测能力,设计了全球宏观尺度监测及我国陆域范围季度监测、重点区域月度监测及应急事件即时响应的卫星遥感监测体系框架;针对自然资源卫星遥感监测需求,充分运用大数据、人工智能、云计算等高新技术,本文提出了基于工作流的监测生产线智能流转与可插拔模块调度控制、遥感影像样本知识库构建、复杂场景自然资源变化自动提取、自然资源特定目标自动提取和自然资源变化图斑全生命周期管理等技术解决方案,构建了遥感监测业务化应用技术流程,实现了我国陆域范围自然资源全要素季度监测、重点区域高频次精准监测、特定目标即时监测能力,并在自然资源执法督察和地表水变化等监测中得到应用。 相似文献