共查询到20条相似文献,搜索用时 15 毫秒
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<正>日前,Aeroflex推出首款真正的便携式GPS与Galileo位置模拟器GPSG-1000。GPSG-1000重量轻、易于使用、可配置,并且价格低廉。通过提供可创建三维模拟的低成本12信道测试,该产 相似文献
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《Air & Space Europe》1999,1(2):33-36
Given the present policy of the US to provide the basic GPS signal free of charge, it would be illusory to imagine that Galileo could be developed and provided exclusively by the private sector. 相似文献
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《Air & Space Europe》1999,1(2):37-41
The Commission's Communication of January 1998 summarised the roles and responsibilities which should be included in a GNSS organisational framework. The GNSS-2 Forum has further refined the work on these questions. 相似文献
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Multipath (MP) is the dominant error source in Global Positioning System (GPS) code-based position solutions requiring high accuracy. A technique is introduced here to mitigate error due to ground-reflected MP signals. The technique uses two orthogonal dipoles to capture the direct GPS signal and the ground-reflected GPS signal. Adjusting the amplitude and phase of the received voltage between the two dipoles can reduce the impact of MP error. Theoretical derivations of this technique are performed for a GPS signal upon reflection from dry soil, seawater, and fresh water. The theoretical results are verified with a real world experiment on the aforementioned surfaces. GPS pseudo-range (PR) and carrier-to-noise ratio (C/No) measurements for specific satellites are used to verify the predicted theoretical results. 相似文献
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《Air & Space Europe》1999,1(2):22
In its conclusions of 17 March 1998 on the European Commission's communication ‘Towards a Trans-European Positioning and Navigation Network — including a European strategy for Global Satellite Navigation Systems (GNSS)’, the European Union (EU) Council of Ministers requested the Commission to present recommendations on the future European approach to global satellite navigation. 相似文献
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《Air & Space Europe》1999,1(2):29-32
This article considers which architecture would be best suited to meet the demands of users in a cost-effective manner. It represents the first outline of Galileo. 相似文献
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《Air & Space Europe》1999,1(2):42-44
In line with the conclusions of the previous articles in this dossier, the following scheme to develop a European GNSS-2 constellation (Galileo) is recommended. It is envisaged that the EU Council of Ministers, and perhaps the European Council, will take decisions on the main issues by the end of June 1999. The European Parliament also has a crucial role to play. Within this framework, the meeting of the ESA Council in May should provide clarification of the role ESA can play in the technical, financial and organisational development of Galileo. 相似文献
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The Galileo E1 open service (OS) and the global positioning system (GPS) L1C are intending to use the multiplexed binary offset carrier (MBOC) modulation in E1/L1 band, including both pilot and data components. The impact of data and pilot codes cross-correlation on the distortion of the discriminator function (i.e., the S-curve) is investigated, when only the pilot (or data) components of MBOC signals are tracked. It is shown that the modulation schemes and the receiver configuration (e.g., the correlator spacing) strongly affect the S-curve bias. In this paper, two methods are proposed to optimize the data/pilot code pairs of Galileo E1 OS and GPS L1C. The optimization goal is to obtain the minimum average S-curve bias when tracking only the pilot components a the specific correlator spacing. Figures of merit, such as S-curve bias, correlation loss and code tracking variance have been adopted for analyzing and comparing the un-optimized and optimized code pairs. Simulation results show that the optimized data/pilot code pairs could significantly mitigate the intra-channel codes cross-correlation, and then improve the code tracking performance of MBOC signals. 相似文献
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《Air & Space Europe》1999,1(2):92
The European Commission and the aerospace industry in Europe have set up AeroSME, a joint activity to encourage and support the participation of small and Medium-sized Enterprises (SMEs) in European Research Programmes. 相似文献
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《Air & Space Europe》1999,1(1):18-23
The present article is the text of the speech given by Javier Alvarez Vara, on the occasion of the AECMA (European Association of Aerospace Industries) Evening Lecture, 15th September 1998 in Brussels. 相似文献
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Pisano J.J. Enge P.K. Levin P.L. 《IEEE transactions on aerospace and electronic systems》1991,27(4):696-708
Various techniques for using simultaneous Global Positioning System (GPS)/Loran data to estimate the propagation uncertainties that limit the absolute accuracy of Loran-C are discussed. Significant improvements in the absolute accuracy of Loran can be achieved with very simple calibrations. The absolute accuracy of Loran in the Gulf of Maine without calibration is presented. The maximum and RMS absolute errors are between 700 and 500 m, depending on the choice of land model. Simple calibrations greatly improve the absolute accuracy of Loran. As shown, if the land conductivities are fixed a priori and a single parameter is optimized, the maximum and RMS absolute errors fall to around 250 and 60 m, respectively. Alternatively, land can be treated as a single conductivity which can be adjusted to reduce offshore additional secondary phase factor errors. The performance of this practice is summarized in tables which show maximum and RMS errors of around 300 to 100 m, respectively 相似文献
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US government policy is established and procedures are being formulated to direct the implementation of techniques providing limited civil access to full GPS accuracy. The results of these efforts balance the conflicting needs of civil GPS navigation and positioning against national security requirements. Granting this access will require sufficient and demonstrable user need, must clearly provide for both national and security interests, and may lead to the imposition of a user service charge. This access will only apply to Precise Positioning Service configured, code-tracking GPS receivers. 相似文献
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