共查询到20条相似文献，搜索用时 109 毫秒
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在Galileo系统建设和GPS现代化的进程中，为实现与BPSK（Bi-phase Shift Keying）的频谱分离，采用了BOC（Binary Offset Carrier）调制。BOC调制在码跟踪精度、多径抑制等方面比BPSK调制具有更好的性能，但其自相关函数的多相关峰特性使得在测距中可能产生偏差，因此，消除相关峰的模糊度是BOC信号接收中非常关键的问题。介绍了一种基于QBOC码的BOC信号码跟踪环路（“BOC十QBOC-BOC”），并推导出该环路码跟踪性能的解析表达式，最后的仿真结果验证了理论推导的正确性，可为BOC信号接收机的设计提供参考。 相似文献
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CCRW技术在MBOC调制信号下多径抑制性能 总被引：1，自引：0，他引：1
由于频谱与二相移键控（BPSK）信号有较好的分离度且具有良好的跟踪性能,多元二进制偏置载波（MBOC）调制为GPS现代化和Galileo系统所采用,其多径抑制技术也成为研究热点。选取了四种典型的码相关参考波形（CCRW）技术,研究了其应用于MBOC信号时的多径抑制性能,并与BPSK和BOC（1,1）调制下的多径抑制性能进行了比较。通过仿真可知,在同等条件下,W2、W3、w4CCRW技术在时系多元二进制偏置载波（TMBOC）调制下多径抑制性能最差,在二进制偏置载波（CBOC）调制下性能最优,但三种方法均优于W1CCRW． 相似文献
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针对导航信号的多径误差分析,在多径误差包络曲线分析方法基础上提出了多径误差包络期望分析方法。与包络曲线分析方法相比,包络期望分析方法能够定量分析导航信号多径误差。基于包络期望分析方法,对同码速率的二进制偏移载波(BOC)调制导航信号与二进制相位控键(BPSK)调制导航信号的多径误差进行了对比分析。结果表明,BOC调制导航信号具有更小的典型多径误差。 相似文献
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BOC调制信号多径误差分析 总被引：1，自引：0，他引：1
针对导航信号的多径误差分析,在多径误差包络曲线分析方法基础上提出了多径误差包络期望分析方法.与包络曲线分析方法相比,包络期望分析方法能够定量分析导航信号多径误差.基于包络期望分析方法,对同码速率的二进制偏移载波(BOC)调制导航信号与二进制相位控键(BPSK)调制导航信号的多径误差进行了对比分析.结果表明,BOC调制导航信号具有更小的典型多径误差. 相似文献
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MBOC（multiplexed binary offset carrier）是GPS—GALILEO互用和兼容性工作组推荐的信号调制体制，其实现方式分为TMBOC和CBOC两种，其中TMBOC（6，1，4／33）已被GPSL1C信号所采用。多径是众多卫星导航系统应用的主要误差源之一，由于不具备时间和空间的相关性，无法通过差分技术消除。本文基于窄相关技术和Double—Delta技术对TMBOC（6，1，4／33）的抗多径性能进行了分析，并与BPSK（1）及BOC（1，1）进行了对比。在同等条件下，TMBOC（6，1，4／33）的抗多径性能优于或等同于BPSK（1）及BOC（1，1）。 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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GNSS satellite-based augmentation systems for Australia 总被引：1，自引：0，他引：1
Suelynn Choy Joost Kuckartz Andrew G. Dempster Chris Rizos Matt Higgins 《GPS Solutions》2017,21(3):835-848
We provided an overview of various satellite-based augmentation systems (SBAS) options for augmented GNSS services in Australia, and potentially New Zealand, with the aim to tease out key similarities and differences in their augmentation capabilities. SBAS can technically be classified into two user categories, namely SBAS for aviation and “non-aviation” SBAS. Aviation SBAS is an International Civil Aviation Organization (ICAO) certified civil aviation safety-critical system providing wide-area GNSS augmentation by broadcasting augmentation information using geostationary satellites. The primary aim was to improve integrity, availability and accuracy of basic GNSS signals for aircraft navigation. On the other hand, “non-aviation” SBAS support numerous GNSS applications using positioning techniques such as wide-area differential-GNSS (DGNSS) and precise point positioning (PPP). These services mainly focus on delivering high-accuracy positioning solutions and guaranteed levels of availability, and integrity remains secondary considerations. Next-generation GNSS satellites capable of transmitting augmentation signals in the L1, L5 and L6 frequency bands will also be explored. These augmentation signals have the data capacity to deliver a range of augmentation services such as SBAS, wide-area DGNSS and PPP, to meet the demands of various industry sectors. In addition, there are well-developed plans to put in place next-generation dual-frequency multi-constellation SBAS for aviation. Multi-constellation GNSS increases robustness against potential degradation of core satellite constellations and extends the service coverage area. It is expected that next-generation SBAS and GNSS will improve accuracy, integrity, availability and continuity of GNSS performance. 相似文献
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在中国构建全球导航卫星连续运行站网及其服务系统 总被引：1，自引：0，他引：1
全球导航卫星连续运行站系统可以维持相应地区的高精度、三维、地心、动态坐标框架,提供集约化的定位和导航服务,成为当前国际和国内发展迅速的一项基础设施建设。该系统可以广泛服务于国家大地基准、气象、地球动力学、地学灾害监测以及位置服务等领域。介绍了全球导航卫星系统连续运行站在国内建设的现状。提出了发展我国全球导航卫星系统连续运行站系统当前存在的三个方面的问题。对在中国构建国家级GNSSCORS系统的目的、原则和方案等方面进行了讨论。 相似文献
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Potentialities of multifrequency ionospheric correction in Global Navigation Satellite Systems 总被引：1，自引：1，他引：0
The first-order ionospheric error is reduced in the dual-frequency Global Navigation Satellite Systems (GNSS). In this paper,
the possibility of eliminating ionospheric higher-order errors in the multifrequency GNSS is explored. Since the second-order
error associated with the geomagnetic field effect on the refractive index can be eliminated in dual-frequency measurements,
we explore the possibility of eliminating third-order errors in triple-frequency GNSS in view of phase scintillations. A connection
between the possibility of improving the multifrequency GNSS accuracy and diffraction effects in radio signal propagation
through the randomly inhomogeneous ionosphere is shown. The numerical simulation has revealed that the systematic, residual
ionospheric error is considerably reduced when we pass on from dual-frequency to triple-frequency measurements. The change
in the residual error variance during such a transition depends however on the relationship between the inner scale of the
turbulent spectrum of ionospheric irregularities and the Fresnel radius. Given the inner scale larger than the Fresnel radius,
not only the systematic error, but also the standard deviation reduces when we pass on from dual-frequency to triple-frequency
measurements. Otherwise, when the Fresnel radius exceeds the inner scale, the variance increases with increasing number of
frequencies in use. 相似文献
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全球卫星导航系统中,地面监测站和主控站通信传输容易受到宽带和窄带干扰的影响,导致卫星导航系统精确性和完好性降低。分析研究利用扩频增益抑制宽带干扰和利用陷波滤波器抑制窄带干扰,解决地面监测站和主控站站间通信抗宽带和窄带干扰问题,为增强卫星导航系统精确性和完好性提供了保障。 相似文献
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基于CORS的分米级GNSS差分定位云服务研究 总被引：1，自引：0，他引：1
面向GNSS大众应用领域海量高精度位置服务需求，提出了一种基于CORS的分米级差分定位云服务建设方法，采用虚拟格网用户生成改正数的形式，通过设计解算服务器与业务服务器分离的云服务模式，解决了传统CORS服务中基准站数据安全风险大、用户并发访问数量受限的问题，并以API和SDK形式面向用户和开发者提供应用服务，降低了高精度位置服务专业技术门槛。同时，依托本文研究成果，基于湖南省位置服务平台（HNCORS），设计并实现了基于CORS的分米级GNSS差分定位云服务架构，并以丢包率、外符合精度、高并发访问为指标进行测试。结果表明，本文设计的云服务架构具有较好的精度、稳定性和可靠性，在高精度位置服务应用中具有较好的应用前景，也可为其他省级CORS网的高精度位置服务云平台建设提供技术参考。 相似文献
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北斗三号卫星导航系统（BeiDou-3 navigation satellite system,BDS-3）全球组网工作全面建成,标志着BDS-3迈入全球定位、导航和授时服务的新时代。为了全面比较BDS-3系统与其余全球导航卫星系统（global navigation satellite system,GNSS）非组合精密单点定位（precise point positioning,PPP）性能,重点分析不同分析中心BDS-3精密轨道和钟差产品的一致性、BDS-3/GNSS卫星可用性、BDS-3/GNSS单系统及多系统融合PPP定位性能。结果表明,基于5个分析中心的精密轨道和钟差产品,BDS-3静态PPP三维均方根误差约为2.31~4.00 cm,其单系统收敛时间明显慢于其余GNSS系统,GPS系统的加入对BDS-3/GNSS双系统融合PPP改善效果最为明显,且四系统融合能够有效地缩短收敛时间,并提高动态PPP定位精度。随着BDS-3系统的发展以及轨道和钟差产品的进一步完善,BDS-3同样具备其余GNSS系统提供优质导航定位服务的潜力。 相似文献
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The Andalusian Positioning Network (RAP) is a regional GNSS permanent network in Southern Spain that offers two public services for precise positioning: real-time (RAP-Internet Protocol [IP]) and post processing (RAP-File Transfer Protocol [FTP]). Most of the registered users are linked to the construction sector, so the collapse of the housing bubble and the Spanish economic crisis influenced the use of RAP services from 2008. The behaviour of these services has differed somewhat, although analysis for the years 2008–2013 reveals a general decline. Since 2009, the RAP-FTP service demand fell by 50%, but the RAP-IP service was stable until October 2011, when it began a steep decline in December 2012. Analysing the temporal demand and the geospatial connections of RAP-IP with economic impact indicators, we found a high linear correlation between this service and jobs in the construction sector (.98) and permit building (.96). The real-time and associated geoinformation are its main advantages. 相似文献
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传统的基于行业用户需求而建立的集中式高精度导航定位服务模式在可靠性、可扩展性以及服务多样性等方面已无法满足大众用户的精密定位需求。结合云平台技术,提出了云定位的概念,通过综合管理和整合各类定位资源,实现多种定位手段的资源共享、技术融合和优化配置。给出了云定位的架构图,并讨论了GNSS网络RTK,GNSS广域精密定位,Wi-Fi定位,通信基站定位等多种手段在定位云上的综合和服务实现。云定位在可扩展性、可靠性、系统维护成本以及用户使用灵活性等方面都具有传统的精密定位服务模式所无法比拟的优势;通过云定位,用户不仅可以获取各类精密定位服务,还能实现多种定位资源的优化配置,定制个性化的应用;为精密导航定位的大众化普及提供有效的商业模式和技术途径。 相似文献
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Xiaoli Liu Muqing Liang Yu Morton Pau Closas Ting Zhang Zhigang Hong 《GPS Solutions》2014,18(2):163-175
The objective of this work is to investigate the performances of orthogonal frequency division multiplexing (OFDM) and minimum frequency shift keying (MSK) modulations as potential future global navigation satellite systems (GNSS) signal modulation schemes. MSK is used in global system for mobile communications because of its spectral efficiency, while OFDM is used in WLAN and digital video broadcast-terrestrial because of its multipath mitigation capability. These advantages of MSK and OFDM modulations render them as promising modulation candidates for future GNSS signals to offer enhanced performances in challenging environments. Gabor bandwidth and multipath error envelopes of these two modulations were computed and compared with those of the current global positioning system (GPS), Galileo, and Beidou signal modulations. The results show that OFDM modulation demonstrated promises as a viable future GNSS modulation, especially for signals that require pre-filtering bandwidths larger than 2 MHz, while MSK modulation is more desirable for pre-filtering bandwidth below 2 MHz where it exhibits the largest Gabor bandwidth. 相似文献