共查询到20条相似文献，搜索用时 31 毫秒
1.
Influence of different GPS receiver antenna calibration models on geodetic positioning 总被引：1，自引：0，他引：1
Q. Baire C. Bruyninx J. Legrand E. Pottiaux W. Aerts P. Defraigne N. Bergeot J. M. Chevalier 《GPS Solutions》2014,18(4):529-539
To better understand how receiver antenna calibration models contribute to GPS positioning error budget, we compare station positions estimated with different calibration models: igs05.atx, igs08.atx and individual antenna calibrations. First, the impact of switching from the igs05.atx antenna calibration model to the igs08.atx antenna calibration model is investigated using the EUREF Permanent Network historical data set from 1996 until April 2011. It is confirmed that these position offsets can be effectively represented by the igs05.atx to igs08.atx latitude-dependent model. Then, we demonstrate that the position offsets resulting from the use of individual calibrations instead of type mean igs08.atx calibrations can reach up to 1 cm in the up component, while in the horizontal, the offsets generally stay below 4 mm. Finally, using six antennas individually calibrated by a robot as well as in an anechoic chamber, we observe a position agreement of 2 mm in the horizontal component and a bias of 5 mm in the up component. Larger position offsets, dependent on the antenna/radome type, are, however, found when these individual calibrations are compared to type mean calibrations of two tested antennas. 相似文献
2.
Absolute calibration of GPS antennas: laboratory results and comparison with field and robot techniques 总被引：5，自引：2，他引：5
A critical assessment of the accuracy of GPS antenna calibration is most effectively done by comparison between different calibration methods. We present new chamber calibrations of five different GPS receiver antenna types in an anechoic chamber and a comparison of an individual antenna calibrated by the absolute field calibration technique with robot mount of IfE/GEO++. The accuracy is described using standard error parameters which allow the characterization of the quality of different antennas. The results validate the absolute calibration methods at the 1-mm level and confirm the presence of significant variations in quality between antennas of different design. For the antenna pattern we directly use the measured phase variations and do not have to fit any functions for the chamber calibrations. We include the results of an earlier test made with a set of identical antennas calibrated at five different institutions: two using the absolute field technique with robot mount and three others applying the standard field calibration with reference antenna. 相似文献
3.
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
4.
Estimation of elevation-dependent satellite antenna phase center variations of GPS satellites 总被引：16，自引：7，他引：9
A method for the estimation of the phase center variations of GPS satellite antennas using global GPS data is presented. First estimations have shown an encouraging repeatability from day to day and between satellites of the same block. Thus, two different satellite antenna patterns for Block II/IIA and for Block IIR with a range of about 4 cm and an accuracy of less than 1 mm could be found. The present approach allows the creation of a consistent set of receiver and satellite antenna patterns and phase center offsets. Thereby, it is possible to switch from relative to absolute phase center variations without a scale problem in global networks. This changeover has an influence on troposphere parameters, reduces systematic effects due to uncorrect antenna modeling and should diminish the elevation dependence of GPS results.
AcknowledgmentsThe authors thank Prof. G. Seeber (University of Hannover) and Dr. G. Wübbena (Geo++ GmbH) and their groups for their kindness in making available the absolute field calibration results derived from robot measurements. 相似文献
5.
Phase variations of GPS receiving antennas are a significant error component in precise GPS applications. A calibration procedure
has been developed by Geo++ and the Institut für Erdmessung, which directly determines absolute phase center variations (PCVs)
without any multipath influence by field measurements. The precision and resolution of the procedure allows the determination
of reliable azimuthal variations. PCV may affect long-term static GPS differently than real-time GPS, depending on the applications.
At the same time, different antenna types are involved. Less investigations have been done on absolute PCV of rover antennas
than on geodetic antennas which, however, becomes more important due to the mixed antenna situation in GPS reference networks
and RTK networks. The concepts of the absolute PCV field calibration are summarized and emphasis is placed on a variety of
absolute PCV patterns of geodetic and rover antennas.
Electronic Publication 相似文献
6.
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
7.
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
8.
9.
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
10.
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
11.
Oliver Montenbruck Miquel Garcia-Fernandez Yoke Yoon Steffen Schön Adrian Jäggi 《GPS Solutions》2009,13(1):23-34
Phase center variations of the receiver and transmitter antenna constitute a remaining uncertainty in the high precision orbit
determination (POD) of low Earth orbit (LEO) satellites using GPS measurements. Triggered by the adoption of absolute phase
patterns in the IGS processing standards, a calibration of the Sensor Systems S67-1575-14 antenna with GFZ choke ring has
been conducted that serves as POD antenna on various geodetic satellites such as CHAMP, GRACE and TerraSAR-X. Nominal phase
patterns have been obtained with a robotic measurement system in a field campaign and the results were used to assess the
impact of receiver antenna phase patterns on the achievable positioning accuracy. Along with this, phase center distortions
in the actual spacecraft environment were characterized based on POD carrier phase residuals for the GRACE and TerraSAR-X
missions. It is shown that the combined ground and in-flight calibration can improve the carrier phase modeling accuracy to
a level of 4 mm which is close to the pure receiver noise. A 3.5 cm (3D rms) consistency of kinematic and reduced dynamic
orbit determination solutions is achieved for TerraSAR-X, which presumably reflects the limitations of presently available
GPS ephemeris products. The reduced dynamic solutions themselves match the observations of high grade satellite laser ranging
stations to 1.5 cm but are potentially affected by cross-track biases at the cm-level. With respect to the GPS based relative
navigation of TerraSAR-X/TanDEM-X formation, the in-flight calibration of the antenna phase patterns is considered essential
for an accurate modeling of differential carrier phase measurements and a mm level baseline reconstruction.
相似文献
| Oliver MontenbruckEmail: |
12.
GPS Solutions - The GPS satellite transmitter antenna phase center offsets (PCOs) can be estimated in a global adjustment by constraining the ground station coordinates to the current International... 相似文献
13.
施品浩 《武汉大学学报(信息科学版)》1990,(1)
本文讨论了GPS测量的重要误差来源之一——接收机天线相位中心漂移误差,研究了表征平均相位中心的基本参数及其检测和处理方法。如果用户设备进行了这种检测,并对观测成果作了相应的修正,目前大部分商品接收机在几十公里以内的短过测量中,精度可以提高到3 mm+2 ppm·d(d为边长,单位:km),同时解决了混合机组参加GPS网观测和处理的难题。 相似文献
14.
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
15.
介绍了GNSS天线相位中心改正的基本概念和定义,分析了相位中心偏差（PCO）和变化（PCV）的改正公式,以及天线相位中心改正从相对相位中心模型到绝对相位中心模型的演变,最后结合软件对相位中心改正的实现方法进行了介绍。 相似文献
16.
Driven by the comprehensive modernization of the GLONASS space segment and the increased global availability of GLONASS-capable
ground stations, an updated set of satellite-specific antenna phase center corrections for the current GLONASS-M constellation
is determined by processing 84 weeks of dual-frequency data collected between January 2008 and August 2009 by a worldwide
network of 227 GPS-only and 115 combined GPS/GLONASS tracking stations. The analysis is performed according to a rigorous
combined multi-system processing scheme providing full consistency between the GPS and the GLONASS system. The solution is
aligned to a realization of the International Terrestrial Reference Frame 2005. The estimated antenna parameters are compared
with the model values currently used within the International GNSS Service (IGS). It is shown that the z-offset estimates are on average 7 cm smaller than the corresponding IGS model values and that the block-specific mean value
perfectly agrees with the nominal GLONASS-M z-offset provided by the satellite manufacturer. The existence of azimuth-dependent phase center variations is investigated
and uncertainties in the horizontal offset estimates due to mathematical correlations and yaw-attitude modeling problems during
eclipse seasons are addressed. Finally, it is demonstrated that the orbit quality benefits from the updated GLONASS-M antenna
phase center model and that a consistent set of satellite antenna z-offsets for GPS and GLONASS is imperative to obtain consistent GPS- and GLONASS-derived station heights. 相似文献
17.
Precise orbit determination of the Sentinel-3A altimetry satellite using ambiguity-fixed GPS carrier phase observations 总被引：1，自引：0，他引：1
The Sentinel-3 mission takes routine measurements of sea surface heights and depends crucially on accurate and precise knowledge of the spacecraft. Orbit determination with a targeted uncertainty of less than 2 cm in radial direction is supported through an onboard Global Positioning System (GPS) receiver, a Doppler Orbitography and Radiopositioning Integrated by Satellite instrument, and a complementary laser retroreflector for satellite laser ranging. Within this study, the potential of ambiguity fixing for GPS-only precise orbit determination (POD) of the Sentinel-3 spacecraft is assessed. A refined strategy for carrier phase generation out of low-level measurements is employed to cope with half-cycle ambiguities in the tracking of the Sentinel-3 GPS receiver that have so far inhibited ambiguity-fixed POD solutions. Rather than explicitly fixing double-difference phase ambiguities with respect to a network of terrestrial reference stations, a single-receiver ambiguity resolution concept is employed that builds on dedicated GPS orbit, clock, and wide-lane bias products provided by the CNES/CLS (Centre National d’Études Spatiales/Collecte Localisation Satellites) analysis center of the International GNSS Service. Compared to float ambiguity solutions, a notably improved precision can be inferred from laser ranging residuals. These decrease from roughly 9 mm down to 5 mm standard deviation for high-grade stations on average over low and high elevations. Furthermore, the ambiguity-fixed orbits offer a substantially improved cross-track accuracy and help to identify lateral offsets in the GPS antenna or center-of-mass (CoM) location. With respect to altimetry, the improved orbit precision also benefits the global consistency of sea surface measurements. However, modeling of the absolute height continues to rely on proper dynamical models for the spacecraft motion as well as ground calibrations for the relative position of the altimeter reference point and the CoM. 相似文献
18.
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
19.
Results of the estimation of azimuth-dependent phase center variations (PCVs) of GPS satellite antennas using global GPS data
are presented. Significant variations of up to ±3–4 mm that are demonstrated show excellent repeatability over eight years.
The application of the azimuthal PCVs besides the nadir-dependent ones will lead to a further reduction in systematic antenna
effects. In addition, the paper focuses on the benefit of a possible transition from relative to absolute PCVs. Apart from
systematic changes in the global station coordinates, one can expect the GPS results to be less dependent on the elevation
cut-off angle. This, together with the significant reduction of tropospheric zenith delay biases between GPS and VLBI, stands
for an important step toward more consistency between different space geodetic techniques. 相似文献
20.
Use of GPS tracking data from different dual-frequency receiver types (cross-correlating vs. codeless) has revealed satellite-dependent
biases in pseudorange observables P1 (Y-code) and C1 (C/A, Clear Acquisition code). These biases can have a direct effect
on clock estimates, carrier phase bias fixing, and other parameters estimated in GPS data processing. A set of satellite-specific
compensatory pseudorange offsets is calculated, and each is applied to a wee of daily global network analyses in which satlellite,
receiver, atmospheric, and Earth rotation parameters are estimated. Results from these analyses are then compared to those
from corresponding baseline cases in which no biases were applied. There is also some evidence that suggests that the pseudorange
biases differ even among codeless receiver models. Hence, a second set of offsets is computed on a different basis, and compared
with the baseline model in a similar manner. A preliminary examination of C1-P1 variations over time is presented. Finally,
recommendations are made for the use of the calculated offsets, and consideration is given to a future dissemination of updates
to these values as necessary. ? 2001 John Wiley & Sons, Inc. 相似文献