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11.
High-frequency multipath would be problematic for studies at seismic or antenna dynamical frequencies as one could mistakenly
interpret them as signals. A simple procedure to identify high-frequency multipath from global positioning system (GPS) time
series records is presented. For this purpose, data from four GPS base stations are analyzed using spectral analyses techniques.
Additional data, such as TEQC report files of L1 pseudorange multipath, are also used to analyze the high-frequency multipath
and confirmation of the high-frequency multipath inferred from the phase records. Results show that this simple procedure
is effective in identification of high-frequency multipath. The inferred information can aid interpretation of multipath at
the GPS site, and is important for a number of reasons. For example, the information can be used to study GPS site selections
and/or installations.
相似文献
| Clement OgajaEmail: |
12.
针对一般的加性高斯白噪声系统,结合平方根无迹卡尔曼滤波和加性噪声无迹卡尔曼滤波的优点,提出了无须增广变量的加性高斯白噪声系统的平方根无迹卡尔曼滤波方法,并给出了其详细算法.该算法较传统方法具有较小的运算负担,较高的精度,并能有效克服滤波的发散.该方法应用于卫星导航系统动态多径估计问题,能够高效准确地得到直射信号与多径信号的各个参数的估计,从而抑制多径的影响.仿真试验表明,该方法在诸多方面改进了已有方法,是一种高效准确的非线性滤波方法. 相似文献
13.
Dmitry Tatarnikov Vladimir Filippov Igor Soutiaguine Andrey Astahov Anton Stepanenko Pavel Shamatulsky 《GPS Solutions》2005,9(3):194-201
An antenna ground plane (GP) plays a major role in the mitigation of multipath coming from underneath the antenna. A distinct
trend in user antenna size and weight reduction has been observed during recent years. With this focus in mind, an overview
of conventional flat conductive and impedance GP is provided. Results of modern developments of passive vertically stacked
structures are discussed. The possibility of obtaining a reasonable level of multipath mitigation with vertical structures
of several centimeters is shown. 相似文献
14.
Knowledge of the local direction of multipath at a particular site is important for a number of reasons. For example, such
information can be used to study site selections or during monument design for GPS installations. We present a MATLAB program
for creating colorized polar maps of high-frequency multipath using TEQC report files of single-epoch data. The maps, although
not necessarily indicating the actual local direction of multipath on the ground, give the orientation with respect to the
geometry of the satellites in the sky. This information can aid the interpretation of ground multipath geometry at the site.
We give an example of short-span data with ∼0.05 Hz multipath (i.e. repeat period ≈ 20 s) although the program can be modified
for long-term measurements as well. 相似文献
15.
M. E. Gorbunov 《Journal of Atmospheric and Solar》2003,65(16-18):1361-1367
A short-wave asymptotic method of modeling radio signals registered during radio occultation experiments is discussed. The method uses the theory of Fourier integral operators. Use of this method allows for a faster simulation of radio occultation data as compared to the method of multiple phase screens. The method was tested using global fields from analyses of the European Centre for Medium-Range Weather Forecast. The comparison of the asymptotic solution with the multiple phase screen method shows their good agreement. The limits of the applicability of the new method are discussed. 相似文献
16.
We present sea level observations derived from the analysis of signal-to-noise ratio (SNR) data recorded by five coastal GPS stations. These stations are located in different regions around the world, both in the northern and in the southern hemisphere, in different multipath environments, from rural coastal areas to busy harbors, and experience different tidal ranges.The recorded SNR data show periodic variations that originate from multipath, i.e. the interference of direct and reflected signals. The general assumption is that for satellite arcs facing the open sea, the rapid SNR variations are due to reflections off the sea surface. The SNR data recorded from these azimuth intervals were analyzed by spectral analysis with two methods: a standard analysis method assuming a static sea level during a satellite arc and an extended analysis method assuming a time dependent sea level during a satellite arc.The GPS-derived sea level results are compared to sea level records from co-located traditional tide gauges, both in the time and in the frequency domain. The sea level time series are highly correlated with correlation coefficients to the order of 0.89–0.99. The root-mean-square (RMS) difference is 6.2 cm for the station with the lowest tidal range of 165 cm and 43 cm for the station with the highest tidal range of 772 cm. The relative accuracy, defined as the ratio of RMS and tidal range, is between 2.4% and 10.0% for all stations.Comparing the standard analysis method and the extended analysis method, the results based on the extended analysis method agree better with the independent tide gauge records for the stations with a high tidal range. For the station with the highest tidal range (772 cm), the RMS is reduced by 47% when using the extended analysis method. Furthermore, the results also indicate that the standard analysis method, assuming a static sea level, can be used for stations with a tidal range of up to about 270 cm, without performing significantly worse than the extended analysis method.Tidal amplitudes and phases are derived by harmonic analysis of the sea level records. Again, a high level of agreement is observed between the tide gauge and the GPS-derived results. Comparing the GPS-derived results, the results based on the extended analysis method show a higher degree of agreement with the traditional tide gauge results for stations with larger tidal ranges. Spectral analysis of the residuals after the harmonic analysis reveals remaining signal power at multiples of the draconitic day. This indicates that the observed SNR data are to some level disturbed by additional multipath signals, in particular for GPS stations that are located in harbors. 相似文献
17.
当前地震勘探仪器的应用技术分析 总被引：10，自引：5，他引：5
本文对当前地震数据采集记录系统(地震仪器)的结构与使用状况进行了分类和分析．介绍了408UL、IMAGE、ARIES、BOX、IT等目前最常用的几种大型有线或无线地震仪器;介绍了目前地震仪器采用的∑-△型的ADC技术、网络遥测技术、多进制数字调制技术、蜂窝技术以及GPS时钟同步技术等多种新技术．从目前地震勘探所面临的环境及保护、勘探成本、勘探效益、勘探精度等问题出发,阐述了仪器所面,临的道数和传感器等问题,认为地震仪器应该向传感、定位、采集、传输一体化的高度智能自由组合系统发展。 相似文献
18.
We compare two methods for monitoring the dynamic response of tall buildings to wind loading, using data from a 280-m-high
building in Singapore. The first method is based on accelerometer measurements. The second method is based on the Global Positioning
System (GPS) technology. The GPS can in principle detect absolute displacements with lower frequencies than the accelerometers,
but the GPS positioning signal is usually very noisy. We propose a systematic procedure for modeling the stochastic and systematic
components of the GPS displacement time series and for extracting the weak structural response from the dominant noise. The
spectrum of the building response obtained from the filtered GPS data exhibits a dominant peak at 0.19 Hz. The frequency of
the peak coincides with that obtained from the analysis of the accelerometer data. The proposed analysis of the GPS signal
provides a method for cross-validating the GPS and accelerometer measurements, and shows that “educated” filtering of the
GPS signal can reveal essential features of the building’s response to wind loading. 相似文献
19.
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
20.
With the successful launch of the sixteen MEO satellites of the Beidou-3 global satellite navigation system and the broadcast of new signals, Beidou has officially entered the global construction stage while the international GNSS Monitoring and Assessment System (iGMAS) is also performing systematic testing and evaluation on various aspects of operational performance from satellite end to ground receiving end of Beidou-3 system. This paper analyzed and evaluated the observation quality of new signals B1C and B2a broadcasted by the twelve new Beidou-3 MEO satellites on the observation data integrity rate, multipath error, pseudorange noise and Carrier-to-Noise Ratio (CNR) compared with GPS and GALILEO. The results show that the observation data integrity rate of B1C signal is better than that of B2a signal in the Beidou-3 system. In the aspects of multipath error, pseudorange noise and CNR, B2a signal is better than that of B1C. The performances of the twelve MEO satellites of Beidou-3 are equivalent, that is, for Beidou-3, the consistency of satellites can be guaranteed. In terms of pseudo-range noise, Beidou-3 is slightly worse than GPS and GALILEO While the observation data integrity rate, multipath error and CNR of Beidou-3 are equivalent to those of GPS and GALILEO. 相似文献