共查询到20条相似文献，搜索用时 140 毫秒
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给出了一种用于对抗干扰的GPS接收盲自适应波束形成算法。该方法基于一种新的解扩器和一阶恒模算法。优点是在形成波束对准期望信号并消除干扰时,不需要直接给出这些信号的DOA（信号来向）信息。计算机仿真结果给出了对抗干扰的性能。 相似文献
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论文研究了星载GPS低轨卫星定轨技术的基本理论和方法,研制了星载GPS低轨卫星约化动力法定轨软件,针对约化动力法和推广卡尔曼滤波存在的问题,开展了星载GPS低轨卫星自适应事后和实时定轨研究,论文最后对星载GPS编队卫星相对定位技术进行了研究。主要工作及创新点概括如下： 相似文献
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GaryF.Hatke 《GPS天线及其抗干扰技术》2002,(4M):32-38
军用GPS系统必须能在敌方干扰时工作。由于附近干扰机和远距离卫星源之间存在巨大的功率差，所以GPS信号的扩频增益对实现抗干扰（A／J）保护能力是不够的。本提出了采用自适应天线调零系统来实现附加的抗干扰（A／J）保护能力，但是目前的系统，如AB－1就不能抑制与安装在飞机上阵列相关的近场多径干扰。本分析了GPS调零时空自适应（STAP）波束形成器的设计，包括STAP处理器对GPS位置计算的影响，该位置通过测量不同卫星信号的到达时差（TDOA）来计算。本提出了两种新疑结构，其性能通过在1：4比例大小的F－16飞机上进行的多次测量来模拟确定。 相似文献
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针对卫星钟差难以用精确模型来进行预报的问题,将极端学习机（extreme learning machine,ELM）神经网络用于导航卫星钟差预报。针对ELM网络隐层结构难以确定的问题,提出了基于自适应共振理论（adaptive resonance theory,ART）网络思想的ELM网络结构设计算法。该算法将ART网络的聚类特性用于ELM网络结构设计中,通过对输入向量与已存模式的相似度比较将输入向量进行分类,自适应地确定隐层节点规模。使用GPS卫星钟差数据进行30 d的预报实验,结果表明,此方法的钟差预报精度明显优于二次多项式模型和灰色系统模型。 相似文献
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在对广域差分GPS定位算法精度分析的基础上,建立了通用GPS系统运算平台,构造了浮点类型,并提出了DSP运行环境中的高精度函数算法,完成了对广域差分GPS定位算法的优化,编制了基于通用DSP系统的广域差分GPS定位算法软件,成功研制了广域差分用户接收机系统。 相似文献
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为了系统验证SINS／GPS紧组合系统的性能,基于GPS软件接收机,进行了仿真系统构建。仿真系统由轨迹发生器、GPS中频信号模拟器、IMU信号模拟器、GPS软件接收机、SINS导航解算模块、组合滤波算法和导航性能分析模块等部分构成,其中详细设计了GPS软件接收机中的捕获和跟踪算法、SINS解算以及基于伪距和伪距率的组合滤波算法。仿真结果表明：紧组合导航系统收敛性较好,能够一定程度上抑制惯导系统误差的积累,有较好的导航性能。设计的该系统满足紧组合导航系统性能验证的需要,也为后续的超紧组合研究奠定了良好的基础。 相似文献
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本文首先概述了GPS基线解算与网平差的关键算法，阐述了自编软件功能模块划分及各模块间的信息传递过程，最后通过实测数据对软件进行测试分析，并与美国Trimble公司的TGO软件解算结果进行对比。结果表明：软件具有可行性和可靠性，能够正确地进行基线解算与网平差运算。 相似文献
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Applied Research Laboratories, The University of Texas at Austin (ARL:UT) has established a cross platform open source software
project called the GPSTk or the GPS Toolkit. The GPSTk consists of a library and collection of applications that support GPS
research, analysis, and development. The code is released under the terms of the Lesser GNU Public License. The GPSTk supports
a broad range of functionality. This includes reading and writing observations in standard formats, such as RINEX, BINEX,
and SP3, ephemeris evaluation, position determination, receiver autonomous integrity monitoring (RAIM), atmospheric delay
modeling, cycle slip detection and correction, and P-code generation. The GPSTk provides the core set of functionality that
is used for GPS research and development at ARL:UT. ARL:UT has been involved with satellite navigation since Transit (the
precursor to GPS) in the 1960s and is currently conducting research in a wide variety of GPS-related fields, including precise
surveys, monitor station networks, and ionospheric studies. The GPSTk is a community-wide resource for all users of GPS and
GNSS technology. Participation is welcomed in all areas including: bug reports, new algorithms, suggestions for improvement,
and contributions of additional functionality or applications. ARL:UT continually improves the library, shepherds community
participation, and is committed to the project’s development and maintenance.
The GPS Toolbox is a column dedicated to highlighting algorithms and source code utilized by GPS Engineers and scientists.
If you have an interesting program or software package you would like to share with our readers, please pass it along; e-mail
it to us at gps-toolbox@ngs.noaa.gov. To comment on any of the source code discussed here, or to download source code, visit
our website at . This column is edited by Stephen Hilla, National Geodetic Survey, NOAA, Silver Spring, Maryland, and Mike Craymer, Geodetic
Survey Division, Natural Resources Canada, Ottawa, Ontario, Canada. 相似文献
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Grace Xingxin Gao Liang Heng Achim Hornbostel Holmer Denks Michael Meurer Todd Walter Per Enge 《GPS Solutions》2013,17(4):561-573
The Galileo E5a/E5b signals and the Global Positioning System (GPS) L5 signal lie within the aeronautical radionavigation services (ARNS) band. They suffer interference from the services in this frequency band, in particular, pulsed signals from distance measuring equipment (DME) and tactical air navigation (TACAN) systems. To maintain system accuracy and integrity, interference mitigation is beneficial and necessary. We first present the real DME/TACAN environment at Stanford, CA as an example to illustrate the need for mitigating DME/TACAN interference. We then propose a time and frequency joint mitigation algorithm—Hybrid Blanking and its simplified version, frequency domain adaptive filtering (FDAF) for hardware implementation. Finally, a flight measurements campaign was performed over a European DME/TACAN hotspot near Frankfurt, Germany, to record a worst-case DME interference environment. Recorded data from the flight tests mixed with injected GNSS signals verify the effectiveness of the proposed mitigation algorithm. 相似文献
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论述GNSS多系统融合定位的数学模型、分析各项误差处理策略以及参数估计方法,基于日本东京海洋大学RTKLIB软件进行GPS、GLONASS、Galileo、BDS多系统融合定位试验,并分析其动/静态定位稳定性和精度。试验结果表明:GNSS多系统融合收敛时间与GPS单系统相比缩短30%~50%,定位精度与GPS单系统相比可以提高20%~50%。此外,在卫星高度截止角大于40°和不利观测环境条件下,单系统可见卫星数不足,从而导致无法进行连续定位,但多系统融合可视卫星可获得比较好的定位精度,在建筑物密集区、山区和卫星遮挡较为严重的恶劣条件下具有实际应用价值。 相似文献
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The mitigation of radio frequency interference (RFI) has a fundamental role in global navigation satellite system (GNSS) applications,
especially when a high level of availability is required. Several electromagnetic sources, in fact, might degrade the performance
of the global positioning system (GPS) and Galileo receivers, and their effects can be either in-band (i.e., secondary harmonics
generated by transmitters of other communication systems due to non-linearity distortions) or out-of-band (i.e., strong signals
that occupy frequency bandwidths very close to GNSS bands). We investigated the effects of real out-of-band signals on GNSS
receivers and analyzed the impact on the overall receiver chain in order to evaluate the impact of the interference source.
In particular, the analysis focuses on the spectrum at the front-end output, on the automatic gain control (AGC) behavior,
as well as on the digital processing stages (signal acquisition and tracking) at the analog digital converter (ADC) output.
This study refers to several experiments and data collections performed in interfered areas of downtown Torino (Italy). The
obtained results underline how digital/analog TV transmissions represent a potential interference source for GNSS applications
and might be critical for the safety of life services. 相似文献
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全球导航卫星反射信号遥感GNSS-R(Global Navigation Satellite System Reflectometry)是近年来新兴的一个学科交叉研究领域。本文在调研分析国内外研究进展的基础上,基于GNSS-R工作原理与技术特征,将GNSS-R遥感观测模式定义为双天线模式DAP(Double Antenna Pattern)和单天线模式SAP(Single Antenna Pattern),并对两种观测模式的特性和共性问题进行分析。初步建立GNSS-R遥感应用体系架构,以陆面遥感应用为例,结合近几年参与的GNSS-R观测试验与模型研究工作,给出两种观测模式下GNSS-R遥感的典型应用实例,以期为中国未来地基、空基和星载GNSS-R遥感观测及应用工作的开展提供参考。 相似文献