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1.
Precision spacecraft navigation using a low-cost GPS receiver 总被引：1，自引：1，他引：0
Oliver Montenbruck Paul Swatschina Markus Markgraf Stefano Santandrea Joris Naudet Etienne Tilmans 《GPS Solutions》2012,16(4):519-529
Within the PROBA-2 microsatellite mission, a miniaturized single-frequency GPS receiver based on commercial-off-the-shelf (COTS) technology is employed for onboard navigation and timing. A rapid electronic fuse protects against destructive single-event latch-ups (SEL) and enables a quasi-continuous receiver operation despite the inherent sensitivity to space radiation. While limited to single-frequency C/A-code tracking with a narrow-band frontend, the receiver is able to provide precision navigation services through processing of raw GPS measurements on ground as well as a built-in real-time navigation system. In both cases, ionospheric path delays are eliminated through a combination of L1 pseudorange and carrier phase measurements, which also offers a factor-of-two noise reduction relative to code-only processing. By comparison with satellite laser ranging (SLR) measurements, a 0.3-m (3D rms) accuracy is demonstrated for the PROBA-2 reduced dynamic orbit determinations using post-processed GPS orbit and clock products. Furthermore, the experimental onboard navigation system is shown to provide real-time position information with a 3D rms accuracy of about 1?m, which notably outperforms the specification of the Standard Positioning Service (SPS). In view of their lower hardware complexity, mass budget and power requirements as well as the reduced interference susceptibility, legacy C/A-code receivers can thus provide an attractive alternative to dual-frequency receivers even for demanding navigation applications in low Earth orbit. 相似文献
2.
Precision real-time navigation of LEO satellites using global positioning system measurements 总被引：4，自引：3，他引：1
Continued advancements in remote sensing technology along with a trend towards highly autonomous spacecraft provide a strong
motivation for accurate real-time navigation of satellites in low Earth orbit (LEO). Global Navigation Satellite System (GNSS)
sensors nowadays enable a continuous tracking and provide low-noise radiometric measurements onboard a user spacecraft. Following
the deactivation of Selective Availability a representative real-time positioning accuracy of 10 m is presently achieved by
spaceborne global positioning system (GPS) receivers on LEO satellites. This accuracy can notably be improved by use of dynamic
orbit determination techniques. Besides a filtering of measurement noise and other short-term errors, these techniques enable
the processing of ambiguous measurements such as carrier phase or code-carrier combinations. In this paper a reference algorithm
for real-time onboard orbit determination is described and tested with GPS measurements from various ongoing space missions
covering an altitude range of 400–800 km. A trade-off between modeling effort and achievable accuracy is performed, which
takes into account the limitations of available onboard processors and the restricted upload capabilities. Furthermore, the
benefits of different measurements types and the available real-time ephemeris products are assessed. Using GPS broadcast
ephemerides a real-time position accuracy of about 0.5 m (3D rms) is feasible with dual-frequency carrier phase measurements.
Slightly inferior results (0.6–1 m) are achieved with single-frequency code-carrier combinations or dual-frequency code. For
further performance improvements the use of more accurate real-time GPS ephemeris products is mandatory. By way of example,
it is shown that the TDRSS Augmentation Service for Satellites (TASS) offers the potential for 0.1–0.2 m real-time navigation
accuracies onboard LEO satellites. 相似文献
3.
Different types of GPS clock and orbit data provided by the International GPS Service (IGS) have been used to assess the accuracy
of rapid orbit determination for satellites in low Earth orbit (LEO) using spaceborne GPS measurements. To avoid the need
for reference measurements from ground-based reference receivers, the analysis is based on an undifferenced processing of
GPS code and carrier-phase measurements. Special attention is therefore given to the quality of GPS clock data that directly
affects the resulting orbit determination accuracy. Interpolation of clock data from the available 15 min grid points is identified
as a limiting factor in the use of IGS ultra-rapid ephemerides. Despite this restriction, a 10-cm orbit determination accuracy
can be obtained with these products data as demonstrated for the GRACE-B spacecraft during selected data arcs between 2002
and 2004. This performance may be compared with a 5-cm orbit determination accuracy achievable with IGS rapid and final products
using 5 min clock samples. For improved accuracy, high-rate (30 s) clock solutions are recommended that are presently only
available from individual IGS centers. Likewise, a reduced latency and more frequent updates of IGS ultra-rapid ephemerides
are desirable to meet the requirements of upcoming satellite missions for near real-time and precise orbit determination. 相似文献
4.
This study analyzes the quality of onboard data of tracking signals from GPS satellites on the far side of the earth and determines the orbit of the geostationary satellite using code and carrier phase observations with 30-h and 3-day orbit arc length. According to the analysis results, the onboard receiver can track 6–8 GPS satellites, and the minimum and maximum carrier to noise spectral densities were 24 and 45 dB-Hz, respectively. For a GPS receiver on a high-altitude platform above the navigation constellations, the blocking of the earth and a weak signal strength usually cause a piece-wise GPS signal tracking and an increase in the number of ambiguity parameters. Individual GPS satellites may be continuously tracked for as little as several minutes and as long as 3 h. Moreover, considering the negative sign of elevation angles reflects the fact that GPS satellites are tracked below the receiver in the study. GPS satellites appear mainly in the elevation angle range of ??53° to ??83°, and dilution of precision values could reach ten or one hundred and more. Also, it is observed that when a signal suffers from atmospheric refraction, other GPS signals tracked simultaneously by the receiver experience strong systematic errors in the code observations. Based on single-frequency code and carrier phase measurements, the mean 3D root mean square (RMS) value of the overlap comparisons between 30-h orbit determination arcs is 2.14 m. However, we found that there were also some biases in the carrier phase residuals, which contributed to poor orbit accuracy. To eliminate the effects of the biases, we established a correction sequence for each GPS satellite. After corrections, the mean 3D RMS was reduced to 0.99 m, representing a 53% improvement. 相似文献
5.
针对低轨卫星搭载BDS/GPS接收机实现定轨将成为定轨领域热点的现状,该文讨论了基于星载BDS/GPS实时定轨和精密定轨需要考虑的数学模型,阐述了实时定轨和精密定轨的模型差异。基于自主研发程序,利用高动态信号仿真器仿真的星载BDS/GPS数据研究了基于星载BDS/GPS实时定轨和精密定轨的可行性及其能达到的精度。试验结果表明,星载BDS/GPS实时定轨位置精度为1.19m,速度精度为2.35mm/s。GPS信号发生中断时即仅采用BDS观测数据进行实时定轨时,三维位置误差达到3.73m;星载BDS/GPS精密定轨位置精度为2.30cm,仅采用BDS观测数据进行精密定轨时,三维位置误差可达到8.26cm。 相似文献
6.
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
7.
Results are presented for Michibiki, the first satellite of Japan’s Quasi-Zenith Satellite System. Measurements for the analysis
have been collected with five GNSS tracking stations in the service area of QZSS, which track five of the six signals transmitted
by the satellite. The analysis discusses the carrier-to-noise density ratio as measured by the receiver for the different
signals. Pseudorange noise and multipath are evaluated with dual-frequency and triple-frequency combinations. QZSS uses two
separate antennas for signal transmission, which allows the determination of the yaw orientation of the spacecraft. Yaw angle
estimation results for an attitude mode switch from yaw-steering to orbit-normal orientation are presented. Estimates of differential
code biases between QZSS and GPS observations are shown in the analysis of the orbit determination results for Michibiki.
The estimated orbits are compared with the broadcast ephemerides, and their accuracy is assessed with overlap comparisons. 相似文献
8.
Oliver Montenbruck Yago Andres Heike Bock Tom van Helleputte Jose van den Ijssel Marc Loiselet Christian Marquardt Pierluigi Silvestrin Pieter Visser Yoke Yoon 《GPS Solutions》2008,12(4):289-299
The global navigation satellite system receiver for atmospheric sounding (GRAS) on MetOp-A is the first European GPS receiver
providing dual-frequency navigation and occultation measurements from a spaceborne platform on a routine basis. The receiver
is based on ESA’s AGGA-2 correlator chip, which implements a high-quality tracking scheme for semi-codeless P(Y) code tracking
on the L1 and L2 frequency. Data collected with the zenith antenna on MetOp-A have been used to perform an in-flight characterization
of the GRAS instrument with focus on the tracking and navigation performance. Besides an assessment of the receiver noise
and systematic measurement errors, the study addresses the precise orbit determination accuracy achievable with the GRAS receiver.
A consistency on the 5 cm level is demonstrated for reduced dynamics orbit solutions computed independently by four different
agencies and software packages. With purely kinematic solutions, 10 cm accuracy is obtained. As a part of the analysis, an
empirical antenna offset correction and preliminary phase center correction map are derived, which notably reduce the carrier
phase residuals and improve the consistency of kinematic orbit determination results.
相似文献
| Oliver MontenbruckEmail: |
9.
GPS接收机工作原理及发展现状 总被引：1，自引：0，他引：1
根据GPS接收机的工作原理,分为连续接收机、序贯接收机和多元接收机。讨论了接收机的应用分类,分别为高精度测量型接收机,导航接收机及授时型接收机。根据GPS卫星信号的情况,介绍了GPS接收机的性能指标。根据GNSS的发展现状和卫星信号的实施论述了新一代多模双频接收机指标,根据测试结果证明：这种接收机将是未来GPS接收机的发展方向。 相似文献
10.
基于低轨（low earth orbit,LEO）卫星星载GNSS反射事件的数学判据,分别用BDS、GPS、Galileo、GLONASS和4系统耦合GNSS星座模拟信号源,仿真分析了LEO卫星轨道高度、轨道倾角、下视天线视场角等参量对反射事件数量和时空分布的影响;进而研究了用上述4大GNSS系统进行GNSS反射信号遥感技术（GNSS reflectometry,GNSS-R）探测对接收机通道数量的需求。统计结果表明:LEO卫星轨道越高,天线视场越大,反射事件越多,镜面反射点分布越稠密;轨道倾角越小,反射事件镜面点越趋于赤道地区分布;GNSS-R接收机所需通道数随LEO卫星轨道高度和下视天线视场范围增大而增加;而LEO卫星轨道倾角变化对通道数需求影响不明显。研究结果对GNSS-R低轨卫星系统设计具有一定的理论参考价值。 相似文献
11.
GPS-assisted GLONASS orbit determination 总被引：1，自引：0，他引：1
D. Kuang Y. E. Bar-Sever W. I. Bertiger K. J. Hurst J. F. Zumberge 《Journal of Geodesy》2001,75(11):569-574
Using 1 week of data from a network of GPS/GLONASS dual-tracking receivers, 15-cm accurate GLONASS orbit determination is
demonstrated with an approach that combines GPS and GLONASS data. GPS data are used to define the reference frame, synchronize
receiver clocks and determine troposphere delay for the GLONASS tracking network. GLONASS tracking data are then processed
separately, with the GPS-defined parameters held fixed, to determine the GLONASS orbit. The quality of the GLONASS orbit determination
is currently limited by the size and distribution of the tracking network, and by the unavailability of a sufficiently refined
solar pressure model. Temporal variations in the differential clock bias of the dual-tracking receivers are found to have
secondary impact on the orbit determination accuracy.
Received: 5 January 2000 / Accepted: 15 February 2001 相似文献
12.
随着北斗三号卫星导航系统(BeiDou navigation satellite system-3, BDS-3)开始向全球提供导航服务,独立使用BDS为在轨运行的卫星提供全球覆盖、全时段的定位服务成为可能。结合风云三号D星(FengYun-3D, FY-3D)全球卫星导航系统掩星探测仪(global navigation satellite system occultation sounder, GNOS)的真实在轨数据对天基BDS的定位性能进行了详细的分析。首先,使用BDS真实广播星历计算了在不同轨道高度下的可见卫星数和定位精度因子（position dilution of precision, PDOP）,并结合精密星历分析了广播星历的轨道误差、时钟误差及空间信号测距误差(signal-in-space range error, SISRE)。仿真结果表明,在95%的置信水平下,从地面到2 000 km的轨道高度,BDS在全球范围内最小可见卫星数为6,最大PDOP小于5,星座可用性已经达到100%,全球平均可见卫星数BDS比GPS(global positioning syste... 相似文献
13.
14.
为了满足高动态用户及强干扰条件下的应用需求,提出了一种基于卫星信号矢量跟踪的SINS/GPS深组合导航方法,设计了基于FPGA硬件平台的实施方案。利用组合卡尔曼滤波器反馈回路取代了传统接收机中独立、并行的跟踪环路,能够同时完成所有可视卫星信号的跟踪和导航信息处理;通过矢量跟踪算法对所有可视卫星信号进行集中处理,能够增强跟踪通道对信号载噪比变化的适应能力,从而提高接收机在强干扰或信号中断条件下的跟踪性能;根据SINS导航参数和星历信息推测GPS伪码相位和多普勒频移等参数,用以辅助卫星信号的捕获和跟踪,能够大大缩短接收机的搜索捕获时间,并增强接收机在高动态条件下的跟踪性能。基于矢量跟踪的深组合方法不仅在GPS信号短暂中断期间,能够保证系统的导航精度和可靠性,而且在强干扰环境中能够维持较好的伪码相位和载波频率跟踪性能。 相似文献
15.
Due to their low cost and low power consumption, single-frequency GPS receivers are considered suitable for low-cost space applications such as small satellite missions. Recently, requirements have emerged for real-time accurate orbit determination at sub-meter level in order to carry out onboard geocoding of high-resolution imagery, open-loop operation of altimeters and radio occultation. This study proposes an improved real-time kinematic positioning method for LEO satellites using single-frequency receivers. The C/A code and L1 phase are combined to eliminate ionospheric effects. The epoch-differenced carrier phase measurements are utilized to acquire receiver position changes which are further used to smooth the absolute positions. A kinematic Kalman filter is developed to implement kinematic orbit determination. Actual flight data from China’s small satellite SJ-9A are used to test the navigation performance. Results show that the proposed method outperforms traditional kinematic positioning method in terms of accuracy. A 3D position accuracy of 0.72 and 0.79 m has been achieved using the predicted portion of IGS ultra-rapid products and broadcast ephemerides, respectively. 相似文献
16.
Recent studies have demonstrated the usefulness of global positioning system (GPS) receivers for relative positioning of formation-flying satellites using dual-frequency carrier-phase observations. The accurate determination of distances or baselines between satellites flying in formation can provide significant benefits to a wide area of geodetic studies. For spaceborne radar interferometry in particular, such measurements will improve the accuracy of interferometric products such as digital elevation models (DEM) or surface deformation maps. The aim of this study is to analyze the impact of relative position errors on the interferometric baseline performance of multistatic synthetic aperture radar (SAR) satellites flying in such a formation. Based on accuracy results obtained from differential GPS (DGPS) observations between the twin gravity recovery and climate experiment (GRACE) satellites, baseline uncertainties are derived for three interferometric scenarios of a dedicated SAR mission. For cross-track interferometry in a bistatic operational mode, a mean 2D baseline error (1σ) of 1.4 mm is derived, whereas baseline estimates necessary for a monostatic acquisition mode with a 50 km along-track separation reveal a 2D uncertainty of approximately 1.7 mm. Absolute orbit solutions based on reduced dynamic orbit determination techniques using GRACE GPS code and carrier-phase data allows a repeat-pass baseline estimation with an accuracy down to 4 cm (2D 1σ). To assess the accuracy with respect to quality requirements of high-resolution DEMs, topographic height errors are derived from the estimated baseline uncertainties. Taking the monostatic pursuit flight configuration as the worst case for baseline performance, the analysis reveals that the induced low-frequency modulation (height bias) fulfills the relative vertical accuracy requirement (σ<1 m linear point-to-point error) according to the digital terrain elevation data level 3 (DTED-3) specifications for most of the baseline constellations. The use of a GPS-based reduced dynamic orbit determination technique improves the baseline performance for repeat-pass interferometry. The problem of fulfilling the DTED-3 horizontal accuracy requirements is still an issue to be investigated. DGPS can be used as an operational navigation tool for high-precision baseline estimation if a geodetic-grade dual-frequency spaceborne GPS receiver is assumed to be the primary instrument onboard the SAR satellites. The possibility of using only single-frequency receivers, however, requires further research effort.Deutsche Forschungsgemeinschaft (DFG) research fellow until Sept. 2004 at the Microwaves and Radar Institute, Deutsche Zentrum für Luft- und Raumfahrt (DLR) e.V., 82234 Weßling, Germany 相似文献
17.
Kinematic positions of Low Earth Orbiters based on GPS tracking are frequently used as pseudo-observations for single satellite gravity field determination. Unfortunately, the accuracy of the satellite trajectory is partly limited because the receiver synchronization error has to be estimated along with the kinematic coordinates at every observation epoch. We review the requirements for GPS receiver clock modeling in Precise Point Positioning (PPP) and analyze its impact on kinematic orbit determination for the two satellites of the Gravity Recovery and Climate Experiment (GRACE) mission using both simulated and real data. We demonstrate that a piecewise linear parameterization can be used to model the ultra-stable oscillators that drive the GPS receivers on board of the GRACE satellites. Using such a continuous clock model allows position estimation even if the number of usable GPS satellites drops to three and improves the robustness of the solution with respect to outliers. Furthermore, simulations indicate a potential accuracy improvement of the satellite trajectory of at least 40 % in the radial direction and up to 7 % in the along-track and cross-track directions when a 60-s piecewise linear clock model is estimated instead of epoch-wise independent receiver clock offsets. For PPP with real GRACE data, the accuracy evaluation is hampered by the lack of a reference orbit of significantly higher accuracy. However, comparisons with a smooth reduced-dynamic orbit indicate a significant reduction of the high-frequency noise in the radial component of the kinematic orbit. 相似文献
18.
The combination of GPS measurements and high-fidelity dynamic models via a Kalman filter/smoother, known as the reduced dynamic technique, allows 3D positioning of Low Earth Orbiters to the sub-decimeter level. Such accuracies can only be achieved if the GPS data are nearly continuous, post-processed and a dual-frequency receiver is utilized. The focus of this study is to quantitatively analyze the degradations in position accuracy in the presence of various limitations or constraints, which can be brought on by mission hardware limitations, for example, on micro- or nanosatellites. The constraints explored in this study are as follows: the use of single-frequency data only; real-time processing; limited dynamic modeling due to computing capabilities; and non-continuous GPS receiver operation due to power limits. The experiments are conducted with 6-h data arcs for 7 separate days using data from the CHAllenging Mini-Satellite Payload. A 3D root mean square (rms) error of 15 cm is observed in the best-case solution, in which dual-frequency data are post-processed with all available data. Various levels of accuracy degradations are observed as constraints are placed on this best-case solution. The 3D rms error of the post-processed, single-frequency solution is 68 cm and 1.3 m for the real-time, dual-frequency solution. In very challenging environments, for example, with the receiver on for only 10 min of a 90-min orbit, the 3D rms increases to 350 m. 相似文献
19.
A multi-technique approach for characterizing the SVN49 signal anomaly, part 2: chip shape analysis 总被引：2，自引：1，他引：1
Steffen Thoelert Michael Meurer Stefan Erker Oliver Montenbruck André Hauschild Pat Fenton 《GPS Solutions》2012,16(1):29-39
Due to a satellite internal reflection at the L5 test payload, the SVN49 (PRN1) GPS satellite exhibits a static multipath
on the L1 and L2 signals, which results in elevation-dependent tracking errors for terrestrial receivers. Using a 30-m high-gain
antenna, code and carrier phase measurements as well as raw in-phase and quadrature radio frequency samples have been collected
during a series of zenith passes in mid-April 2010 to characterize the SVN49 multipath and its impact on common users. Following
an analysis of the receiver tracking data and the IQ constellation provided in Part 1 of this study, the present Part 2 provides
an in-depth investigation into chip shapes for the L1 and L2 signals. A single reflection model is found to be compatible
with the observed chip shape distortions and key parameters for an elevation dependent multipath model are derived. A good
agreement is found between multipath parameters derived independently from raw IQ-samples and measurements of a so-called
Vision Correlator. The chip shapes and their observed variation with elevation can be used to predict the multipath response
of different correlator types within a tracking receiver. The multipath model itself is suitable for implementation in a signal
simulator and thus enables laboratory testing of actual receiver hardware. 相似文献
20.
Focusing on carrying out GPS occulatation observations with a receiver set on LEO satellite, this paper develops the LEO orbit simulation system based on which the occultation events can be simulated taking into account the geometric relationship of the satellites and the field of view of the receiver antenna. In this paper, the impacts of 4 types of LEO orbit parameters including argument of latitude (AOL), right ascension of ascending node (RAAN), orbit height and orbit inclination on the distribution and number of occultation events observed with a single LEO satellite are discussed through simulation and some conclusions are drawn. 相似文献