共查询到20条相似文献，搜索用时 31 毫秒
1.
We present experimental results showing the impact of the proposed LightSquared (LS) Long-term Evolution (LTE) signals on both GPS and Galileo civil modulations in the L1/E1 band. The experiments were conducted in radiated mode in a large anechoic chamber. Three Galileo enabled receivers were chosen for the tests, and a state of the art GNSS signal generator was used to simulate both GPS and Galileo signals. The LTE signals were generated by an Agilent Programmable Signal Generator with a license to generate the signals according to the 3GPP LTE FDD standard. The interference impact was measured in terms of a Carrier-to-Noise power spectral density ratio (C/N 0) degradation, in accordance with the methodology which the LS/GPS Technical Working Group (TWG) established by mandate of the FCC. A model for determining the impact of the LS signal on the considered GNSS signals is provided and is validated against experimental data. It is shown that the Galileo E1 Open Service (OS) signal is marginally more susceptible to this form of interference than the GPS L1 C/A signal due to its greater proximity to the lower edge of the L1 band. The impact of LS interference was further analyzed in terms of pseudorange and position errors. Despite its relevance for most GNSS users, this aspect was not considered by the TWG. Measurement and position domain analysis along with the study of the LS impact on the Galileo OS signals are the major contributions. The analysis confirms the results obtained by the TWG and shows that the receiver front-end plays a major role in protecting GNSS signals against RF interference. While it appears that, for now, the LS network will not be deployed, the approach taken and the results obtained herein can be readily adapted for any future terrestrial mobile network that may take the place of LS. 相似文献
2.
Homogeneous reprocessing of GPS,GLONASS and SLR observations 总被引：3，自引：2，他引：1
Mathias Fritsche Krzysztof Sośnica Carlos Javier Rodríguez-Solano Peter Steigenberger Kan Wang Reinhard Dietrich Rolf Dach Urs Hugentobler Markus Rothacher 《Journal of Geodesy》2014,88(7):625-642
The International GNSS Service (IGS) provides operational products for the GPS and GLONASS constellation. Homogeneously processed time series of parameters from the IGS are only available for GPS. Reprocessed GLONASS series are provided only by individual Analysis Centers (i. e. CODE and ESA), making it difficult to fully include the GLONASS system into a rigorous GNSS analysis. In view of the increasing number of active GLONASS satellites and a steadily growing number of GPS+GLONASS-tracking stations available over the past few years, Technische Universität Dresden, Technische Universität München, Universität Bern and Eidgenössische Technische Hochschule Zürich performed a combined reprocessing of GPS and GLONASS observations. Also, SLR observations to GPS and GLONASS are included in this reprocessing effort. Here, we show only SLR results from a GNSS orbit validation. In total, 18 years of data (1994–2011) have been processed from altogether 340 GNSS and 70 SLR stations. The use of GLONASS observations in addition to GPS has no impact on the estimated linear terrestrial reference frame parameters. However, daily station positions show an RMS reduction of 0.3 mm on average for the height component when additional GLONASS observations can be used for the time series determination. Analyzing satellite orbit overlaps, the rigorous combination of GPS and GLONASS neither improves nor degrades the GPS orbit precision. For GLONASS, however, the quality of the microwave-derived GLONASS orbits improves due to the combination. These findings are confirmed using independent SLR observations for a GNSS orbit validation. In comparison to previous studies, mean SLR biases for satellites GPS-35 and GPS-36 could be reduced in magnitude from \(-35\) and \(-38\) mm to \(-12\) and \(-13\) mm, respectively. Our results show that remaining SLR biases depend on the satellite type and the use of coated or uncoated retro-reflectors. For Earth rotation parameters, the increasing number of GLONASS satellites and tracking stations over the past few years leads to differences between GPS-only and GPS+GLONASS combined solutions which are most pronounced in the pole rate estimates with maximum 0.2 mas/day in magnitude. At the same time, the difference between GLONASS-only and combined solutions decreases. Derived GNSS orbits are used to estimate combined GPS+GLONASS satellite clocks, with first results presented in this paper. Phase observation residuals from a precise point positioning are at the level of 2 mm and particularly reveal poorly modeled yaw maneuver periods. 相似文献
3.
A technique for obtaining clock measurements from individual GNSS satellites at short time intervals is presented. The methodology developed in this study allows for accurate satellite clock stability analysis without an ultra-stable clock at the ground receiver. Variations in the carrier phase caused by the satellite clock are isolated using a combination of common GNSS carrier-phase processing techniques. Furthermore, the white phase variations caused by the thermal noise of the collection and processing equipment are statistically modeled and removed, allowing for analysis of clock performance at subsecond intervals. Allan deviation analyses of signals collected from GPS and GLONASS satellites reveal distinct intervals of clock noise for timescales less than 100 s. The clock data collected from GPS Block IIA, IIR, IIR-M, and GLONASS satellites reveal similar stability performance at time periods greater than 20 s. The GLONASS clock stability in the 0.6–10 s range, however, is significantly worse than GPS. Applications that rely on ultra-stable clock behavior from the GLONASS satellites at these timescales may therefore require high-rate corrections to estimate and remove oscillator-based errors in the carrier phase. 相似文献
4.
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
5.
本文给出了GPS/GLONASS双模接收机的总体设计方案,重点对弱信号环境下的接收机信号捕获进行了讨论,采用并行码相位搜索方法和改进的循环相关算法分别对GLONASS信号和GPS信号进行捕获;并利用真实数据对双模接收机性能进行了仿真研究,重点对接收机捕获弱信号的能力,以及在不同信噪比和不同累加数据长度下的捕获概率进行了讨论,结果表明该双模接收机在不需要较长数据长度的情况下能够捕获低信噪比环境下的卫星导航信号,提高了接收机的灵敏度。 相似文献
6.
通过载噪比(CNR)、数据完整率、伪距与载波相位观测值噪声和伪距多路径效应四个指标对北斗三号卫星导航系统(BDS-3)新频点B1C/B2a车载动态数据的特性进行了分析,测试了BDS-3新频点动态精密单点定位(PPP)的性能,并与其它全球卫星导航系统(GNSS)进行了对比. 试验结果表明,BDS-3新频点B2a平均CNR优于北斗卫星导航系统(BDS)其它频率,但略差于GPS L5;相较于其它GNSS,BDS数据完整率相对较高,其中BDS-3 B2a新频点数据完整率最高;BDS-3 B2b伪距观测值噪声最小,B1C和B2a伪距观测值噪声约为B2b信号的3倍,但不同频率相位观测值噪声处于同一量级;对于伪距多路径而言,BDS-3 B1C/B2a 信号略小于B2b 信号. 总体而言,GPS L5信号抑制多路径效应的能力最强. 在动态PPP性能方面,BDS-3 B1C/B2a双频组合动态PPP定位精度最优,其三维(3D)均方根(RMS)误差为0.439 m,相比BDS B1I/B3I、GPS L1/L2、GLONASS G1/G2和Galileo E1/E5a双频组合PPP,其精度改善率分别为49%、56%、81%和42%. 相似文献
7.
面向遥感的GNSS反射信号接收处理系统及实验 总被引：3，自引：0，他引：3
提出了一种新的GNSS-R信号接收处理系统（GNSS-Rreceiver system,GRrSv.2）的结构及信号处理方法。该系统可同时针对直射和反射的GNSS信号协同处理,并输出可配置延迟和多普勒的二维相关值矩阵。为了验证系统的性能,进行了针对海洋和陆地遥感的机载和岸基验证实验,并给出了初步的实验结果。 相似文献
8.
现阶段高轨道航天器导航主要依靠地基测控系统,为了研究全球卫星导航系统(GNSS)技术用于高轨道航天器导航的可行性,对GNSS技术在地球静止轨道(GEO)卫星、倾斜地球同步轨道(IGSO)卫星航天器中的导航精度及适用性展开了分析研究. 采用2021年11月9日的两行轨道数据(TLE)仿真GNSS星座,以不同星下点的GEO卫星和不同倾角的IGSO卫星作为目标星展开导航仿真试验. 实验结果表明:为了满足GNSS解算所需的卫星数量,须通过接收旁瓣信号来增加可见卫星数目. 对GEO目标星而言,当接收机灵敏度高于?169 dB时,导航精度可达30 m;利用GPS对7个不同的GEO或IGSO轨道目标星进行导航实验表明,GPS对目标星导航的位置误差约为35 m;北斗三号(BDS-3)、GPS、GLONASS、Galileo的导航位置误差均值分别为28.03 m、21.16 m、37.15 m、25.09 m,具有良好的内符合精度,其中GPS精度最高,GLONASS精度最低,但大部分时段也在45 m内. 相似文献
9.
Ahmed Elaksher Tarig Ali Franck Kamtchang Christian Wegmann Adalberto Guerrero 《International Journal of Digital Earth》2020,13(5):586-601
ABSTRACTEstablishing reliable elevation differences is imperative for most geoscience and engineering applications. This work has traditionally been accomplished through spirit leveling techniques; however, surveyors have been utilizing satellite positioning systems in measuring height differences for more than a decade. Yet the quality of these heights needs to be evaluated in order to adopt them in different applications. In this article, we present the outcome of an accuracy assessment of height differences obtained with static and RTK surveys. Twenty control points with an average baseline length of 1?km were occupied with dual-frequency GNSS receivers for different time periods. Collected signals were processed using open-source software and verified with an online processing tool. Heights were estimated by processing the GPS and the GLONASS data individually, and combined (i.e. GNSS). Height differences were determined and compared with those measured by spirit levels and corrected through geoid models. Best results were achieved by combining GPS and GLONASS solutions for both static and RTK surveys. Solutions with either GPS or GLONASS satellites were comparable, but in most cases, the GPS solutions performed better. For the static surveys, longer occupation provided much accurate height differences. Inconsistencies among 10 different RTK surveys were minimum for the GPS?+?GLONASS solutions and worst for the GLONASS solutions. The ANOVA, LSD, F, and χ² statistical tests confirmed our findings at the 95% confidence level. 相似文献
10.
在高精度GNSS定位中,接收机天线相位中心偏差(PCO)和天线相位中心变化(PCV)的影响不可忽略。目前,IGS发布的绝对天线相位模型文件中包含了GPS/GLONASS系统的标定值,但是没有发布北斗系统(BDS)的标定值。本文借助机械臂可以控制天线自由旋转,在数小时内实现全方位GNSS观测的特性,采用历元间差分的方法对接收机天线包括GPS L1/L2和BDSB1I/B2I/B3I等多个频点的PCO和PCV分别进行标定和拟合。标定结果表明,比较最小二乘估计的GPS PCO与IGS发布值,其STD和RMS在L1/L2上均小于1 mm;BDS PCO估计值的STD在B1I/B2I/B3I上分别为0.5、0.3、0.3 mm。利用球谐函数拟合的GPS PCV格网值与IGS发布值相比,其偏差在天顶距小于75°时均小于1.5 mm。BDS PCV拟合值范围均在-5~8 mm,且随天顶距变化曲线呈现波谷状。BDS PCV在低高度角处拟合值波动较大,随方位角变化曲线峰值-峰值最大达到了5.6 mm。 相似文献
11.
NLOS GPS signal detection using a dual-polarisation antenna 总被引：2，自引：2，他引：0
The reception of indirect signals, either in the form of non-line-of-sight (NLOS) reception or multipath interference, is a major cause of GNSS position errors in urban environments. We explore the potential of using dual-polarisation antenna technology for detecting and mitigating the reception of NLOS signals and severe multipath interference. The new technique computes the value of the carrier-power-to-noise-density (C/N 0) measurements from left-hand circular polarised outputs subtracted from the right-hand circular polarised C/N 0 counterpart. If this quality is negative, NLOS signal reception is assumed. If the C/N 0 difference is positive, but falls below a threshold based on its lower bound in an open-sky environment, severe multipath interference is assumed. Results from two experiments are presented. Open-field testing was first performed to characterise the antenna behaviour and determine a suitable multipath detection threshold. The techniques were then tested in a dense urban area. Using the new method, two signals in the urban data were identified as NLOS-only reception during the occupation period at one station, while the majority of the remaining signals present were subject to a mixture of NLOS reception and severe multipath interference. The point positioning results were dramatically improved by excluding the detected NLOS measurements. The new technique is suited to a wide range of static ground applications based on our results. 相似文献
12.
目前,全球卫星导航系统(GNSS)已进入以GPS、GLONASS、BDS、Galileo四系统为代表的多系统并存的时代,多系统多频率观测值的综合应用极大地提升了GNSS的服务能力. GNSS自身的数据质量是取得高精度结果的先决条件之一,也是多系统精密定位随机模型构建的关键. 为避免码分多址和频分多址机制不同的影响,本文采用几何无关和M-W组合方法,基于科廷大学实测零基线数据对四系统的载波相位单差残差序列对比分析,并利用高度角随机模型中的正弦模型和指数模型对载波相位观测值精度随高度角变化建模,获得适用于不同系统不同频率观测值的随机模型. 实验分析表明,单差残差序列随高度角变化情况在不同系统不同频率表现出不同特性;Galileo系统L1、L2观测值精度相当,均在0.9 mm左右,其他系统则表现出L2精度比L1精度更差的性质. 高度角加权模型拟合结果表明,正弦模型和指数模型对GPS和Galileo系统的L1、L2精度序列拟合一致性较好,而BDS系统使用正弦模型拟合效果略差,GLONASS系统则不适合采用正弦模型评估L2观测值精度. 相似文献
13.
Reducing the draconitic errors in GNSS geodetic products 总被引：2，自引：2，他引：0
C. J. Rodriguez-Solano U. Hugentobler P. Steigenberger M. Bloßfeld M. Fritsche 《Journal of Geodesy》2014,88(6):559-574
Systematic errors at harmonics of the GPS draconitic year have been found in diverse GPS-derived geodetic products like the geocenter $Z$ -component, station coordinates, $Y$ -pole rate and orbits (i.e. orbit overlaps). The GPS draconitic year is the repeat period of the GPS constellation w.r.t. the Sun which is about 351 days. Different error sources have been proposed which could generate these spurious signals at the draconitic harmonics. In this study, we focus on one of these error sources, namely the radiation pressure orbit modeling deficiencies. For this purpose, three GPS+GLONASS solutions of 8 years (2004–2011) were computed which differ only in the solar radiation pressure (SRP) and satellite attitude models. The models employed in the solutions are: (1) the CODE (5-parameter) radiation pressure model widely used within the International GNSS Service community, (2) the adjustable box-wing model for SRP impacting GPS (and GLONASS) satellites, and (3) the adjustable box-wing model upgraded to use non-nominal yaw attitude, specially for satellites in eclipse seasons. When comparing the first solution with the third one we achieved the following in the GNSS geodetic products. Orbits: the draconitic errors in the orbit overlaps are reduced for the GPS satellites in all the harmonics on average 46, 38 and 57 % for the radial, along-track and cross-track components, while for GLONASS satellites they are mainly reduced in the cross-track component by 39 %. Geocenter $Z$ -component: all the odd draconitic harmonics found when the CODE model is used show a very important reduction (almost disappearing with a 92 % average reduction) with the new radiation pressure models. Earth orientation parameters: the draconitic errors are reduced for the $X$ -pole rate and especially for the $Y$ -pole rate by 24 and 50 % respectively. Station coordinates: all the draconitic harmonics (except the 2nd harmonic in the North component) are reduced in the North, East and Height components, with average reductions of 41, 39 and 35 % respectively. This shows, that part of the draconitic errors currently found in GNSS geodetic products are definitely induced by the CODE radiation pressure orbit modeling deficiencies. 相似文献
14.
随着我国北斗导航系统“全球组网”序幕的拉开,设计实现接收机的兼容互操作功能已变成接收机设计领域的一个研究热点。文中针对GNSS双频兼容互操作接收机信号捕获环节设计中遇到的处理时间长、捕获精度低、硬件资源消耗大、兼容性差等问题,设计一种基于频域处理的信号捕获算法。该算法在传统频域捕获的基础上,优化频域转换资源利用与遍历方式,在能量累加方面加入相干与非相干累加方式,达到微弱信号捕获。借助Xilinx软件Vivado及其仿真工具,对整个捕获系统进行了仿真实现,验证了算法设计的准确性,本算法可以捕获信号功率-135 dB以上的信号,可捕获的载波多普勒频率范围满足实际工程需求。在实际工程验证中,本算法能较好地满足工程应用性能要求。 相似文献
15.
基于载波相位历元间差分测速方法,建立了全球卫星导航系统（global navigation satellite system, GNSS）单点测速的数学模型,分析了其误差源,并结合实测数据对多GNSS系统各频点及其无电离层组合、不同系统组合的测速精度进行了对比分析。实验结果表明：不同系统不同频点的测速精度有所差异,BDS(BeiDou navigation satellite system)的B1I、B1C、B3I、B2a频点和Galileo(Galileo positioning system)的E1、E5a、E6、E5b、E5频点的测速精度相当,水平方向优于1.5 mm/s,高程方向优于3 mm/s;BDS的B2I和GPS的L1、L2、L5频点的测速精度相当,水平方向在1.5～2 mm/s,高程方向在3～4mm/s;GLONASS(globalnavigationsatellitesystem)的G1、G2频点测速精度最差,水平方向在3～4 mm/s,高程方向在5～5.5 mm/s;双频无电离层组合由于放大了观测值噪声,其测速精度低于单频。此外,多GNSS组合增加了可见卫星数,降低... 相似文献
16.
Estimation and evaluation of real-time precipitable water vapor from GLONASS and GPS 总被引：1，自引：0，他引：1
Cuixian Lu Xingxing Li Maorong Ge Robert Heinkelmann Tobias Nilsson Benedikt Soja Galina Dick Harald Schuh 《GPS Solutions》2016,20(4):703-713
The revitalized Russian GLONASS system provides new potential for real-time retrieval of zenith tropospheric delays (ZTD) and precipitable water vapor (PWV) in order to support time-critical meteorological applications such as nowcasting or severe weather event monitoring. In this study, we develop a method of real-time ZTD/PWV retrieval based on GLONASS and/or GPS observations. The performance of ZTD and PWV derived from GLONASS data using real-time precise point positioning (PPP) technique is carefully investigated and evaluated. The potential of combining GLONASS and GPS data for ZTD/PWV retrieving is assessed as well. The GLONASS and GPS observations of about half a year for 80 globally distributed stations from the IGS (International GNSS Service) network are processed. The results show that the real-time GLONASS ZTD series agree quite well with the GPS ZTD series in general: the RMS of ZTD differences is about 8 mm (about 1.2 mm in PWV). Furthermore, for an inter-technique validation, the real-time ZTD estimated from GLONASS-only, GPS-only, and the GPS/GLONASS combined solutions are compared with those derived from very long baseline interferometry (VLBI) at colocated GNSS/VLBI stations. The comparison shows that GLONASS can contribute to real-time meteorological applications, with almost the same accuracy as GPS. More accurate and reliable water vapor values, about 1.5–2.3 mm in PWV, can be achieved when GLONASS observations are combined with the GPS ones in the real-time PPP data processing. The comparison with radiosonde data further confirms the performance of GLONASS-derived real-time PWV and the benefit of adding GLONASS to stand-alone GPS processing. 相似文献
17.
在分析传统GPS/GLONASS组合PPP数学模型中忽略GLONASS码IFB不足的基础上,提出一种基于"多参数"的组合PPP与码IFB估计算法。将"频间偏差"与"系统时差"参数进行合并,通过引入多个独立的"时频偏差"参数对组合PPP中的GLONASS码IFB进行函数模型补偿,同时可实现基于单个测站观测数据的码IFB精确估计。对配备6种GNSS品牌接收机的30个IGS站实测数据进行GLONASS码IFB估计与分析。结果表明:各品牌接收机不同频率通道的GLONASS码IFB可达数米,且表现出与频率的明显相关性,但难以通过简单函数建模为其提供精确的先验改正值;相同品牌接收机的GLONASS码IFB整体上具有相似的特性,而在个别测站会表现出异常特征;即使接收机类型、固件版本及天线类型完全相同的测站,GLONASS码IFB值也可能存在显著差异。新算法能实现对GLONASS码IFB的有效补偿,明显加快组合PPP的收敛速度。虽然引入多个附加参数会导致函数模型自由度减小,但对定位精度的影响有限,与传统"单参数"法进行组合PPP的定位精度相当。 相似文献
18.
本文在扼要叙述GLONASS发展状况的基础上,分析比较了GLONASS与GPS各自的优缺点,给出了两个系统的坐标及时间的转换关系。最后列出了目前GLONASS接收机的生产厂商状况,仅供读者参考。 相似文献
19.
利用全球约110个国际GNSS服务（International GNSS Service,IGS）测站2013年全年观测数据,分析和研究了GPS和全球卫星导航系统（global navigation satellite system,GLONASS）卫星偏航姿态对其精密轨道和钟差的影响。结果表明,偏航姿态对不同型号GPS卫星轨道和钟差的影响程度不同,当采用偏航姿态改正后地影期的BLOCK ⅡA型卫星轨道改善可达17 mm,BLOCK ⅡF为近5 mm,而BLOCK ⅡR几乎不受影响。由于偏航姿态对GLONASS-M卫星定轨精度影响较大,因此,当改正偏航姿态后所有GLONASS卫星相对于IGS最终轨道平均一维差异提高10 mm,相对于德国地学中心（German Research Center for Geosciences,GFZ）最终钟差平均标准差提升0.034 ns。 相似文献
20.
Heading and Pitch Determination Using GPS/GLONASS 总被引：1，自引：0，他引：1
This article describes a single difference approach to estimate heading and pitch with a twin global positoning system (GPS)/GLONASS
(GG) receiver system. Augmentation of GPS with GLONASS is not straightforward, however, because the latter system employs
the frequency division multiple access technique to distinguish the signals form different satellites, rather than the code
division multiple access technique used by GPS. The fact that each GLONASS signal has its own slightly different frequency
makes the double difference (DD) of carrier phase observables no longer possible without modification. To get around this
problem, the use of the between-receiver single difference (SD) of the carrier phase observables is proposed. In this case,
however, receiver clock and other errors do not cancel out. The possibility of using a common external oscillator for the
two receivers is explored. Remaining time and other biases are estimated using a low-pass averaging filter. The single difference
integer ambiguities can then be resolved and the heading and pitch can be determined with a relatively good level of accuracy.
Static and kinematic tests conducted with a pair of GPS/GLONASS receivers are used to validate the approach. Under reduced
visibility, the combined GPS/GLONASS approach is shown to yield superior availability. ? 2000 John Wiley & Sons, Inc. 相似文献