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1.
相位绕转在GNSS定位中是一种误差源,但包含接收机天线旋转的有用信息。提出了一种基于站间单差相位绕转观测数据估计测站天线旋转速率的方法。首先由无几何距离观测值的变化判断天线旋转的开始与结束时间,然后利用单颗卫星站间差分的无几何距离观测值求出测站的天线旋转角度,以及单颗卫星的测站天线旋转速率,最后将所有卫星计算的测站天线旋转速率按照高度角加权平均得到最终的天线旋转速率。通过精心设计实验方案,经实测数据验证,该方法可以精确地估计测站天线的旋转速率,在本实验中,天线旋转平均速率估计精度约为0.5°/s。 相似文献
2.
Carrier phase wind-up in GPS reflectometry 总被引：1，自引：0，他引：1
Georg Beyerle 《GPS Solutions》2009,13(3):191-198
Changes in GPS transmitter and receiver antenna orientations induce variations in observed carrier phase values. An analytic
formula for this well-known carrier phase wind-up correction is derived which generalizes a previous result. In addition,
it is shown that in GPS reflectometry the wind-up values of direct and coherently reflected rays may differ by up to several
centimeters. The results are discussed on the basis of simulated measurements. 相似文献
3.
当GPS、GALILEO卫星运行至与太阳、地球近似共线时,卫星很难维持名义姿态,将出现一段时间的偏航姿态异常。本文基于不同分析中心所提供的精密轨道和钟差产品,在卫星偏航姿态异常时期,设计不同姿态改正策略,选取全球分布的7个MGEX站10 d实测数据,分析了GPS、GALILEO卫星的天线相位中心改正、相位缠绕改正对观测值残差及动态PPP定位结果的影响。研究表明,在卫星偏航姿态异常时期,采用名义偏航姿态对GPS、GALILEO卫星观测值残差的影响可分别达到8和11 cm,在此期间,GPS/GALILEO卫星采用模型偏航姿态,与采用名义偏航姿态相比,动态PPP的E、N、U 3个方向的定位精度可分别提高13.30%、15.77%和12.98%,相较于剔除卫星策略,采用模型偏航姿态的动态PPP定位精度在E、N、U方向可分别提高5.399%、4.430%、5.992%。 相似文献
4.
David Underwood 《GPS Solutions》1999,3(2):48-52
The use of the Global Positioning System (GPS) for position and attitude determination has been exploited for many years.
In these systems, it was required that multiple antennas maintained phase lock to common view satellites for long periods
of time in order to determine integer ambiguities. The challenge to overcome with the ballistic space probe is the high rotational
spin of this particular rocket. The antennas, mounted on the outside skin of the rocket, are in full view of each satellite
only for a fraction of a second before the rocket core eclipses them as it rotates. The antennas rarely see common satellites.
This article describes as system that overcomes these obstacles and provides position, acceleration, attitude, and rotation
rate. The approach uses a two-antenna system. One antenna is mounted either side of the rocket facing out. A hybrid tracking
channel combines signals from both antennas to overcome the signal blockage due to the rocket core as well as to defeat the
effect on the tracking channel due to the spin. The amplitude and phase of the spin rotation signature from each satellite
is extracted from the dual antenna data and used to compute the attitude and spin rate of the vehicle. ? 1999 John Wiley &
Sons, Inc. 相似文献
5.
在精密单点定位中,相位缠绕是一项不可忽略的误差。相位缠绕的计算严格依赖于卫星姿态的确立,不同的卫星类型产生不同的异常。本文给出了卫星在正常情况下的姿态模型和在异常情况下的姿态改正模型。使用真实数据测试以验证本文所提出模型的正确性。观察滤波收敛后出现异常情况的卫星观测值的残差,结果表明:在异常时期残差最大可能超过20 cm,然而使用本文的改正模型,残差可降低到5 cm以下。使用不同分析中心的精密轨道和钟差产品,效果存在微小差异。II/IIA卫星通过地影区域的时间最长可达1 h,此期间卫星姿态完全受航向角偏差(II/IIA为+0.5°)控制,出了地影区域后30 min,姿态难以模型化,因此这30 min的观测数据不建议采用。 相似文献
6.
LIU Jiyu CHEN Xiaoming 《地球空间信息科学学报》2000,3(1):50-56
l lntroductionIn the winter Of l989 Wuhan Technical Universi-ty of Surveying and Mapping COntracted withTrimble Navigation Ltd. to purchase fOur TrimbIe4000SST receivers. They were required tO suit theaeriaI phWetric work without intreducing avelocity limitation. In February, l993 twO of thereceivers were uPgraded to provide two eventrnarker plugfords and one pulse Per second(lPPS) output axkets. The uPgradd receivers canincormrate external event markers, e. g. the shutter.oPening … 相似文献
7.
天线相位中心改正对GPS精密单点定位的影响 总被引：1，自引：0，他引：1
GPS卫星与接收机由于自身特性以及机械加工等原因,导致其质量中心与相位中心不重合而产生相位中心误差,进而对GPS精密单点定位产生一定影响。介绍GPS天线相位中心偏移(PCO)、变化(PCV)的原理,并分析PCO、PCV,以及不同模型改正对GPS精密单点定位的影响。结果表明,在GPS精密单点定位中,天线相位中心改正不容忽略:在平面方向上,天线相位中心改正对定位影响较小,仅为毫米级;在高程方向上,天线相位中心改正对定位影响较大,可达厘米级;与相对中心改正模型相比,绝对相位中心改正模型精度更高。 相似文献
8.
Multipath is one of the most important error sources in Global Navigation Satellite System (GNSS) carrier-phase-based precise
relative positioning. Its theoretical maximum is a quarter of the carrier wavelength (about 4.8 cm for the Global Positioning
System (GPS) L1 carrier) and, although it rarely reaches this size, it must clearly be mitigated if millimetre-accuracy positioning
is to be achieved. In most static applications, this may be accomplished by averaging over a sufficiently long period of observation,
but in kinematic applications, a modelling approach must be used. This paper is concerned with one such approach: the use
of ray-tracing to reconstruct the error and therefore remove it. In order to apply such an approach, it is necessary to have
a detailed understanding of the signal transmitted from the satellite, the reflection process, the antenna characteristics
and the way that the reflected and direct signal are processed within the receiver. This paper reviews all of these and introduces
a formal ray-tracing method for multipath estimation based on precise knowledge of the satellite–reflector–antenna geometry
and of the reflector material and antenna characteristics. It is validated experimentally using GPS signals reflected from
metal, water and a brick building, and is shown to be able to model most of the main multipath characteristics. The method
will have important practical applications for correcting for multipath in well-constrained environments (such as at base
stations for local area GPS networks, at International GNSS Service (IGS) reference stations, and on spacecraft), and it can
be used to simulate realistic multipath errors for various performance analyses in high-precision positioning. 相似文献
9.
GPS Antenna Calibration at the National Geodetic Survey 总被引：15，自引：2，他引：13
Gerald L. Mader 《GPS Solutions》1999,3(1):50-58
The precise point whose position is being measured when a GPS baseline is determined is generally assumed to be the phase
center of the GPS antenna. However, the phase center of a GPS antenna is neither a physical point nor a stable point. For
any given GPS antenna, the phase center will change with the changing direction of the signal from a satellite. Ideally, most
of this phase center variation depends on satellite elevation. Azimuthal effects are only introduced by the local environment
around each individual antenna site. These phase center variations affect the antenna offsets that are needed to connect GPS
measurements to physical monuments. Ignoring these phase center variations can lead to serious (up to 10 cm) vertical errors.
This article will describe the procedure by which the National Geodetic Survey is calibrating GPS antennas and how this information
may be obtained and used to avoid problems from these antenna variations. ? 1999 John Wiley & Sons, Inc. 相似文献
10.
张植民 《武汉大学学报(信息科学版)》1989,(3)
本文应用局部等效性原理分析无限长圆锥等角螺旋天线中的波型模式,论述了T_(-1)波的有效辐射区。提出适当压缩T_(-1)波的有效辐射区,把小锥角双臂圆锥等角螺旋天线应用于GPS天线的设计思想。文章阐述了该天线的工程设计方法,并给出了其实测指标及使用情况。为GPS正式投入运行,提供了一种性能良好的接收天线。 相似文献
11.
基于DSP技术的GPS接收机天线自适应抗干扰模块的设计与实现 总被引：4，自引：1，他引：4
针对GPS接收机在接收信号的过程中经常存在由于干扰信号的影响而导致接收机无法跟踪锁定有用信号,从而失去精确导航定位的能力问题,提出了一种在天线部分增加一个自适应抗干扰模块的解决办法,并用TI公司的TMS320C6416芯片实现了该方案。 相似文献
12.
Investigation of GPS antenna mean phase centre offsets using a full roving observation strategy 总被引：3，自引：0，他引：3
L. Bányai 《Journal of Geodesy》2005,79(4-5):222-230
In practice, a relatively simple calibration method of full rotation and antenna swapping techniques can be used to control individual GPS antenna mean phase centre offsets without any ground truth survey. Based on these techniques a new full roving strategy is introduced, which is a generalisation of the full rotation and antenna swapping techniques for estimating all of the three components of the mean phase centre offsets in one processing step. This new technique can be used not only for calibration purposes, but also as an observation strategy for a local high-precision network. In the latter case, the proposed method is similar to the classical geodetic approaches, where the biases are cancelled or estimated by proper observation strategies. 相似文献
13.
由于天线本身的特性及机械加工等原因,GPS卫星和接收机天线相位中心与其几何中心不重合,从而产生相位中心偏差。某些类型的天线该偏差甚至可达数cm,直接影响高精度GPS测量的精确可靠性[1]。讨论了GAMIT软件在高精度GPS数据处理中进行天线相位中心改正的原理、方法和策略,结合美国IGS观测站及南加州区域站观测数据,对改正方法及策略进行了实验对比与分析。结果表明:对接收机天线相位中心和卫星天线相位中心采用模型改正,而卫星天线相位中心偏移不改正,所得到的基线解算结果较好[2];地面接收机天线方位角的变化对U方向的基线解算结果有较大影响,在高精度GPS测量中,必须进行天线方位角的变化改正。 相似文献
14.
Generation of a consistent absolute phase-center correction model for GPS receiver and satellite antennas 总被引：26，自引：16，他引：10
Ralf Schmid Peter Steigenberger Gerd Gendt Maorong Ge Markus Rothacher 《Journal of Geodesy》2007,81(12):781-798
The development and numerical values of the new absolute phase-center correction model for GPS receiver and satellite antennas, as adopted by the International GNSS (global navigation satellite systems) Service, are presented. Fixing absolute receiver antenna phase-center corrections to robot-based calibrations, the GeoForschungsZentrum Potsdam (GFZ) and the Technische Universität München reprocessed more than 10 years of GPS data in order to generate a consistent set of nadir-dependent phase-center variations (PCVs) and offsets in the z-direction pointing toward the Earth for all GPS satellites in orbit during that period. The agreement between the two solutions estimated by independent software packages is better than 1 mm for the PCVs and about 4 cm for the z-offsets. In addition, the long time-series facilitates the study of correlations of the satellite antenna corrections with several other parameters such as the global terrestrial scale or the orientation of the orbital planes with respect to the Sun. Finally, completely reprocessed GPS solutions using different phase-center correction models demonstrate the benefits from switching from relative to absolute antenna phase-center corrections. For example, tropospheric zenith delay biases between GPS and very long baseline interferometry (VLBI), as well as the drift of the terrestrial scale, are reduced and the GPS orbit consistency is improved. 相似文献
15.
当太阳相对于卫星轨道面的高度角较小时,北斗导航卫星将不会跟踪太阳位置,卫星姿态发生异常复杂的变化后一段时间内处于零偏模式。在此期间采用名义姿态将影响卫星天线相位中心偏差、相位缠绕等误差计算,进而使精密单点定位(PPP)参数估计和天顶对流层延迟估计出现偏差。研究表明,在北斗导航卫星处于零偏期间,采用名义姿态计算的相位缠绕、天线相位中心偏差中存在超过15cm的误差。在此期间的北斗卫星采用零偏姿态改正相位缠绕等误差,与采用名义姿态相比,动态PPP位置参数N、E、U的估计精度可以提高53.2%、54.2%、39.3%,静态PPP位置参数N、E、U的估计精度可以提高61.0%、72.3%、58.4%,天顶对流层延迟估计精度提高33.0%。 相似文献
16.
变形监测中GPS信号衍射误差的环境建模法 总被引：1，自引：0，他引：1
信号衍射是GPS结构变形监测的重要误差源之一.GPS天线周围的建筑物是常见的信号衍射体.针对在变形监测中观测环境相对固定之特点,提出一种基于环境模型的衍射误差建模算法.若干试验表明所提方法能有效检测并削弱衍射误差对变形监测结果的影响. 相似文献
17.
通过指出测量天线高的两种不规范操作,剖析了GPS天线高的测量方法及误差特性。而后首先从原理上分析了受天线高影响下的GPS基线和独立环闭合差的精度,然后通过某案例对数据进行处理,将两种受天线高影响下的上述测量成果与正常情况下的成果作比较,对理论分析进行证实。结果表明由天线高产生的粗差对短基线的测量成果影响较大,对长基线也有一定的影响。进而得出结论,即对于基线较短的校园GPS控制网,必须要重视对天线高的正确测量方法。而对工程单位布设的基线较长的GPS控制网,要获取高精度的定位成果,也不能忽视天线高的测量工作。 相似文献
18.
Markus Rothacher 《GPS Solutions》2001,4(4):55-60
Three major GPS antenna calibration methods are available toda: the relative field calibrations using the GPS data collected
on short baselines, the absolute field calibrations, where the GPS antenna is rotated and tilted by a robot, and calibration
measurements in an anechoic chamber. Mean antenna offsets and the elevation-dependent phase center variations of GPS antennas
determined by all three techniques are compared to assess their accuracy. The analysis of global GPS data with these sets
of calibration values reveals that the offsets and variations of the satellite antenna phase centers have to be considered,
too, to obtain a consistent picture. ? 2001 John Wiley & Sons, Inc. 相似文献
19.
20.
Phase center modeling for LEO GPS receiver antennas and its impact on precise orbit determination 总被引：7，自引：5，他引：7
Adrian Jäggi R. Dach O. Montenbruck U. Hugentobler H. Bock G. Beutler 《Journal of Geodesy》2009,83(12):1145-1162
Most satellites in a low-Earth orbit (LEO) with demanding requirements on precise orbit determination (POD) are equipped with
on-board receivers to collect the observations from Global Navigation Satellite systems (GNSS), such as the Global Positioning
System (GPS). Limiting factors for LEO POD are nowadays mainly encountered with the modeling of the carrier phase observations,
where a precise knowledge of the phase center location of the GNSS antennas is a prerequisite for high-precision orbit analyses.
Since 5 November 2006 (GPS week 1400), absolute instead of relative values for the phase center location of GNSS receiver
and transmitter antennas are adopted in the processing standards of the International GNSS Service (IGS). The absolute phase
center modeling is based on robot calibrations for a number of terrestrial receiver antennas, whereas compatible antenna models
were subsequently derived for the remaining terrestrial receiver antennas by conversion (from relative corrections), and for
the GNSS transmitter antennas by estimation. However, consistent receiver antenna models for space missions such as GRACE
and TerraSAR-X, which are equipped with non-geodetic receiver antennas, are only available since a short time from robot calibrations.
We use GPS data of the aforementioned LEOs of the year 2007 together with the absolute antenna modeling to assess the presently
achieved accuracy from state-of-the-art reduced-dynamic LEO POD strategies for absolute and relative navigation. Near-field
multipath and cross-talk with active GPS occultation antennas turn out to be important and significant sources for systematic
carrier phase measurement errors that are encountered in the actual spacecraft environments. We assess different methodologies
for the in-flight determination of empirical phase pattern corrections for LEO receiver antennas and discuss their impact
on POD. By means of independent K-band measurements, we show that zero-difference GRACE orbits can be significantly improved
from about 10 to 6 mm K-band standard deviation when taking empirical phase corrections into account, and assess the impact
of the corrections on precise baseline estimates and further applications such as gravity field recovery from kinematic LEO
positions. 相似文献