共查询到20条相似文献,搜索用时 43 毫秒
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单频GPS整周模糊度动态快速求解的研究 总被引:3,自引:1,他引:2
提出了一种动态快速求解整周模糊度的方法,即先对系数阵进行QR分解,然后通过矩阵变换使模糊度参数和位置参数分离,从而降低矩阵的维数,满足实时动态求解的要求,最后应用LAMBDA方法搜索模糊度。为验证该算法,用单频GPS接收机进行了静态定位和动态定位两种试验。结果表明,静态定位误差小于1cm,动态定位误差小于3cm。由此可见,该方法能够为动态用户快速而精确地实施GPS单频动态定位。 相似文献
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GPS/GLONASS载波相位测量模糊度解算方法 总被引:3,自引:1,他引:3
GPS/GLONASS组合载波相位测量,在快速静态和动态定位等方面的应用具有一定的优势。由于GLONASS采用频分多址的方式识别卫星,每颗卫星的载波频率各不相同,所以在载波测量数据处理中不能采用与GPS载波相位测量数据处理相同的方法。文中就GLONASS、GPS/GLONASS组合载波相位测量整周模糊度解算的基本思路和方法进行了介绍。 相似文献
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根据残差二次型次小与最小之差进行整周模糊角度确认的关键是差值的分布,只有得到了合理的差值分布才可确定合理的界值。文中基于原有的两种方法及这两方法的不足,从理论上导出了满足条件的差值分布,并作了一定的说明。 相似文献
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整周模糊度搜索方法的效率比较和分析 总被引:4,自引:0,他引:4
GPS整周模糊度的快速、正确求解是利用GPS载波相位进行高精度定位中最为关键的问题,目前应用最广泛的模糊度解算方法是搜索法。本文比较了不同搜索法的搜索效率,并对搜索的算法和过程进行内在原因的分析。 相似文献
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针对GPS-BDS系统偏差会导致GPS和BDS系统间的混合双差模糊度不具有整数特性,且其不完全稳定的问题,该文提出一种GPS/BDS系统偏差实时在线估计方法。通过将双差模糊度以单差模糊度之差的形式进行求解,然后再将以周为单位的单差模糊度投影为双差模糊度,以此消除GPS和BDS不同波长的影响;在此基础上,采用Kalman滤波对系统偏差进行实时动态估计。实验结果表明,该方法采用较少历元的观测数据便可使系统偏差收敛,并且收敛后十分稳定,可以将其作为校正参数;加入系统偏差改正的GPS/BDS紧组合定位在恶劣环境下表现良好,可将模糊度固定平均所需时间缩短29%,模糊度固定成功率提高45%。 相似文献
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In this article, an algorithm for clock offset estimation of the GPS satellites is presented. The algorithm is based on a
Kalman-filter and processes undifferenced code and carrier-phase measurements of a global tracking network. The clock offset
and drift of the satellite clocks are estimated along with tracking station clock offsets, tropospheric zenith path delay
and carrier-phase ambiguities. The article provides a brief overview of already existing near-real-time and real-time clock
products. The filter algorithm and data processing scheme is presented. Finally, the accuracy of the orbit and clock product
is assessed with a precise orbit determination of the MetOp satellite and compared to results gained with other real-time
products.
相似文献
André HauschildEmail: |
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An algorithm for very accurate absolute positioning through Global Positioning System (GPS) satellite clock estimation has
been developed. Using International GPS Service (IGS) precise orbits and measurements, GPS clock errors were estimated at
30-s intervals. Compared to values determined by the Jet Propulsion Laboratory, the agreement was at the level of about 0.1 ns
(3 cm). The clock error estimates were then applied to an absolute positioning algorithm in both static and kinematic modes.
For the static case, an IGS station was selected and the coordinates were estimated every 30 s. The estimated absolute position
coordinates and the known values had a mean difference of up to 18 cm with standard deviation less than 2 cm. For the kinematic
case, data obtained every second from a GPS buoy were tested and the result from the absolute positioning was compared to
a differential GPS (DGPS) solution. The mean differences between the coordinates estimated by the two methods are less than
40 cm and the standard deviations are less than 25 cm. It was verified that this poorer standard deviation on 1-s position
results is due to the clock error interpolation from 30-s estimates with Selective Availability (SA). After SA was turned
off, higher-rate clock error estimates (such as 1 s) could be obtained by a simple interpolation with negligible corruption.
Therefore, the proposed absolute positioning technique can be used to within a few centimeters' precision at any rate by estimating
30-s satellite clock errors and interpolating them.
Received: 16 May 2000 / Accepted: 23 October 2000 相似文献
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Impact of GPS differential code bias in dual- and triple-frequency positioning and satellite clock estimation 总被引:1,自引:0,他引:1
The features and differences of various GPS differential code bias (DCB)s are discussed. The application of these biases in dual- and triple-frequency satellite clock estimation is introduced based on this discussion. A method for estimating the satellite clock error from triple-frequency uncombined observations is presented to meet the need of the triple-frequency uncombined precise point positioning (PPP). In order to evaluate the estimated satellite clock error, the performance of these biases in dual- and triple-frequency positioning is studied. Analysis of the inter-frequency clock bias (IFCB), which is a result of constant and time-varying frequency-dependent hardware delays, in ionospheric-free code-based (P1/P5) single point positioning indicates that its influence on the up direction is more pronounced than on the north and east directions. When the IFCB is corrected, the mean improvements are about 29, 35 and 52% for north, east and up directions, respectively. Considering the contribution of code observations to PPP convergence time, the performance of DCB(P1–P2), DCB(P1–P5) and IFCB in GPS triple-frequency PPP convergence is investigated. The results indicate that the DCB correction can accelerate PPP convergence by means of improving the accuracy of the code observation. The performance of these biases in positioning further verifies the correctness of the estimated dual- and triple-frequency satellite clock error. 相似文献
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Polynomial interpolation of GPS satellite coordinates 总被引:4,自引:2,他引:4
This article describes an algorithm for polynomial interpolation of GPS satellite coordinates and its implementation in MATLAB.
The algorithm is intended for real-time processing software and computes the position and velocity of GPS satellites from
both broadcast and precise ephemerides. Tests with different orders of polynomials, and with different time spans used for
polynomial fitting, show suitable settings with respect to the required interpolation precision. 相似文献
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The treatment of the permanent tidal deformation of the Earth in GPS computation has been an almost unmentioned topic in the GPS literature. However, the ever increasing accuracy and the need to combine the GPS based coordinates with other methods requires a consistent way to handle the tides. Our survey shows that both the ITRF-xx coordinates and the GPS based coordinates are nowadays reduced to a non-tidal crust, conventionally defined using physically meaningless parameters. We propose to use instead the zero-crust concept which corresponds to concepts already accepted in the resolution of IAG in 1983 for gravimetric works. 相似文献
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In the precise point positioning(PPP),some impossible accurately simulated systematic errors still remained in the GPS observations and will inevitably degrade the precision of zenith tropospheric delay(ZTD) estimation.The stochastic models used in the GPS PPP mode are compared.In this paper,the research results show that the precision of PPP-derived ZTD can be obviously improved through selecting a suitable stochastic model for GPS measurements.Low-elevation observations can cover more troposphere informat... 相似文献
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It is a known fact that obtaining accurate GPS carrier-phase measurements involves fixed, unknown whole-cycle ambiguity parameters.
As the use of cosine functions to eliminate any double-difference integer ambiguities causes spatial ambiguity problems, both
reasonably approximated positions and wavelength-dependent convergence ranges are of the utmost importance. Differential GPS-based
position solutions are first smoothed to create a polynomial trajectory, leading to less variable position approximations.
Long-wavelength wide-lane phase combinations will then be utilized to facilitate convergent GPS positioning, on a stage-by-stage
basis. Although double-difference ionospheric path delays are often interpreted as nuisance parameters, they can be obtained
when the respective cosines of the original L1 and L2 carrier phases undergo a simultaneous least-squares estimation. In particular,
quadratic forms of the estimated phase residuals will be linked with hypothesis testing to allow for a meaningful statistical
inference. Some low-dynamics experiments are then performed to prove the feasibility of the proposed hierarchical positioning
concept.
Electronic Publication 相似文献