共查询到20条相似文献，搜索用时 203 毫秒
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利用GPS进行变形监测在各个领域中的应用越来越广泛。如何利用GPS的观测数据进行变形量的高精度单历元解算是一个难点。国内学者提出了单历元似单差算法进行小变形的单历元解算,但需要利用其他方法对接收机钟差进行计算。根据站间单差观测方程之间的相关性,可以将接收机钟差之差及其他一些通过站间单差未能消除的未知量作为一个未知参数在单历元观测方程中与变形量一同求解。利用该方法对小变形试验数据的解算结果精度达到了毫米级。 相似文献
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提出了一种动态准实时滤波算法,将基线长度作为一虚拟观测值与伪距相位观测值进行联合建模,以提高GPS动态单频单历元定向算法解算的成功率及正确率。利用LAMBDA方法初步求解整周模糊度的备选值,利用基线长度约束模糊度,计算得到单个历元的解;再根据载体的运动特性,采用一种动态适应滤波算法,剔除解算错误的值,并和解算错误或解算失败的历元进行插值和修正。对实测数据处理分析表明：该方法能够将基线约束算法的定向正确率提高5-10％左右,使其稳定性得到进一步提高。 相似文献
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北斗导航系统已经可以为亚太地区提供导航服务,其中精度的测试和评估是目前研究的热点。本文以4个连续观测站的观测数据为基础,进行了不同时长静态基线解算,并与精确定位结果进行比较,发现静态解算精度优于3 cm,E、U、V三个方向的向量精度随着基线观测时长的增加而提高。同时进行北斗动态单历元基线解算,与精确定位结果相比,计算发现北斗单历元动态基线解算精度优于0.2 m,并且E、U、V三个方向的向量精度随着基线观测时间的长度增加而提高,有趋于稳定的趋势。比较结果表明,北斗系统具有良好的稳定性,监测时间越长,定位精度越高。 相似文献
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姿态测量中GPS双频观测的应用 总被引：1，自引：0，他引：1
随着GPS定位技术的发展和完善,利用GPS进行动态载体的姿态测量具有广阔的发展前景.姿态测量问题中,实时、高精度的解算整周模糊度是关键.利用双频观测、RATI0检验等方法进行单历元整周模糊度的解算,得到较好的结果.因此,这一方法可以应用到动态载体姿态测量当中去. 相似文献
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组合码和相位观测值在线解双差模糊度的算法 总被引：4，自引：0，他引：4
如何在线精确地求解整周模糊度,是ＧＰＳ高精度动态相对定位的关键问题。在线解算取决于很多因素：基线长度、数据处理方法、接收机的性能（如双频还是单频）以及抗ＡＳ和ＳＡ的能力等。现代双频ＧＰＳ接收机能获得载波相位和Ｌ１、Ｌ２频道上的精度伪距观测值,组合这４个观测值可进行单历元整周模糊度解算。文中对组合码和相位观测值在线解整周度的算法进行了试验和分析,得出了很有实用意义的结合。 相似文献
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桥梁变形观测中GPS数据处理方法的研究 总被引：1，自引：0，他引：1
对桥梁变形体利用GPS进行变形监测,并通过GPS接收机随机软件进行外业观测数据的解算,研究GPS数据处理中解算基线向量时观测历元、截止高度角参数的最佳设置方法及平差模型的选择,以提高解算精度,为其他同类工程提供一定的参考. 相似文献
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Single-Epoch Ambiguity Resolution for Real-Time GPS Attitude Determination with the Aid of One-Dimensional Optical Fiber Gyro 总被引：9，自引：0，他引：9
High-accuracy real-time GPS-based attitude determination requires that integer ambiguities be resolved very quickly so that
the attitude angles can be output with minimum delay. This article describes an attitude determination algorithm that can
resolve integer ambiguities instantaneously, relative to one antenna of a multi-antenna array configuration. The carrier phase
and pseudorange observations are used with fixed baseline length constraints and fiberoptic gyro data. Real-time stochastic
model improvement using empirical elevation-dependent standard deviation function and an estimated scale factor are a feature
of this algorithm. Integer ambiguity search using the LAMBDA method, sophisticated validation criteria, and an adaptive procedure
has also been implemented within the software. An experiment was carried out using four Leica dual-frequency GPS receivers
(but only the L1 carrier phase and pseudorange data were used) and a low-cost fiberoptic on a car. The results indicate that
integer ambiguities can be resolved on a single-epoch basis with a 98.9% success rate. ? 1999 John Wiley & Sons, Inc. 相似文献
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Testing of a new single-frequency GNSS carrier phase attitude determination method: land,ship and aircraft experiments 总被引：4，自引：1，他引：3
Global navigation satellite system (GNSS) ambiguity resolution is the process of resolving the unknown cycle ambiguities of
the carrier phase data as integers. The sole purpose of ambiguity resolution is to use the integer ambiguity constraints as
a means of improving significantly on the precision of the remaining GNSS model parameters. In this contribution, we consider
the problem of ambiguity resolution for GNSS attitude determination. We analyse the performance of a new ambiguity resolution
method for GNSS attitude determination. As it will be shown, this method provides a numerically efficient, highly reliable
and robust solution of the nonlinearly constrained integer least-squares GNSS compass estimators. The analyses have been done
by means of a unique set of extensive experimental tests, using simulated as well as actual GNSS data and using receivers
of different manufacturers and type as well as different platforms. The executed field tests cover two static land experiments,
one in the Netherlands and one in Australia, and two dynamic experiments, a low-dynamics vessel experiment and high-dynamics
aircraft experiment. In our analyses, we focus on stand-alone, unaided, single-frequency, single-epoch attitude determination,
as this is the most challenging case of GNSS compass processing. 相似文献
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采用方向余弦矩阵描述姿态,建立GPS/陀螺组合姿态确定系统模型,由矩阵Kalman滤波方法解算整周模糊度的浮点解,然后再利用MCLambda方法得到整周模糊度固定解。仿真实验结果表明,附加方向余弦矩阵约束的Kalman滤波方法可以有效地提高整周模糊度浮点解的精度,使得整周模糊度的固定成功率和效率均得到提高,尤其是在GPS观测条件较差的情况下。 相似文献
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New method for single epoch, single frequency land vehicle attitude determination using low-end GPS receiver 总被引：2，自引：1，他引：1
Stand-alone, unaided, single frequency, single epoch attitude determination is the most challenging case of GNSS compass processing. For land vehicle applications, the baseline approximately lies in the plane of the local geodetic horizon. This provides an important constraint that can be exploited to directly aid the ambiguity resolution process. We fully integrate the constraint into the observation equations, which are transformed orthogonally. Our method can acquire the high-quality float solution by means of a heading search strategy. The fixed solution is obtained by weighted constrained integer least squares for each possible heading. The correct solution is identified by three consecutive steps: Kolmogorov?CSmirnov test, heading verification, and global minimizer of the fixed ambiguity objective function. The analysis focuses on single frequency, single epoch land vehicle attitude determination using low-end GPS receivers with very low precision of carrier phase and code measurements. The error analysis is given for choosing a proper baseline length in practical application. Experimental results demonstrate that this scheme can improve the ambiguity success rate for very short baseline. 相似文献
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In a spoofing environment, a Global Navigation Satellite System (GNSS) receiver must employ anti-spoofing techniques for obtaining a normal navigation solution from the GNSS signal. We propose a new method for identifying spoofing signals using the norm of the difference of baseline vectors (NDB) obtained from multiple receivers. The main focuses of this research are to reduce the initial time required to identify the spoofing signal and to mitigate the physical constraints on multiple antennas placement. First, the multi-correlators of each receiver track both GNSS and spoofing signals simultaneously and classify them into two signal groups. Then, the baseline vectors are generated from the double-differenced carrier phase measurements of the classified signal groups, and the NDB is calculated. If the target positions of the spoofing signal groups are almost the same, the NDB has a fairly small value when the base position of the selected baseline vectors is calculated from one of the GNSS groups and the rover positions of the baseline vectors are calculated from each spoofing group of the multiple receivers. Using the NDB, a hypothesis is established, and a hypothesis test is conducted for identifying the spoofing signal. The performance of the proposed test statistics is analyzed with respect to the distance between the GPS antennas and the tuning parameter. Our experimental results show that the proposed method effectively performs spoofing identification with a short baseline. Additionally, the method exhibits a very low probability of fault detection and fast response time. This means that the immediate anti-spoofing can work properly in spoofing environments. 相似文献
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提出了一种利用GPS进行船只姿态测量的新方法。该方法利用接收机之间的波程差并结合当地水平坐标系与载体坐标系的转换关系来进行载体姿态的解算,从而避开了对整周模糊度的求解,具有很高的计算效率及较好的稳定性。通过对计算结果的分析,证明了该算法的有效性,其测姿精度优于0.5°。 相似文献
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Precise GRACE baseline determination using GPS 总被引：13，自引：1，他引：13
Precision relative navigation is an essential aspect of spacecraft formation flying missions, both from an operational and a scientific point of view. When using GPS as a relative distance sensor, dual-frequency receivers are required for high accuracy at large inter-satellite separations. This allows for a correction of the relative ionospheric path delay and enables double difference integer ambiguity resolution. Although kinematic relative positioning techniques demonstrate promising results for hardware-in-the-loop simulations, they were found to lack an adequate robustness in real-world applications. To overcome this limitation, an extended Kalman Filter modeling the relative spacecraft dynamics has been developed. The filter processes single difference GPS pseudorange and carrier phase observations to estimate the relative position and velocity along with empirical accelerations and carrier phase ambiguities. In parallel, double difference carrier phase ambiguities are resolved on both frequencies using the least square ambiguity decorrelation adjustment (LAMBDA) method in order to fully exploit the inherent measurement accuracy. The combination of reduced dynamic filtering with the LAMBDA method results in smooth relative position estimates as well as fast and reliable ambiguity resolution. The proposed method has been validated with data from the gravity recovery and climate experiment (GRACE) mission. For an 11-day data arc, the resulting solution matches the GRACE K-Band Ranging System measurements with an accuracy of 1 mm, whereby 83% of the double difference ambiguities are resolved. 相似文献
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由载波相位观测值直接解算姿态能实现观测及姿态约束信息的最优利用。本文推导了基于失准角及乘性误差四元数的载波相位观测模型,分别建立了有外部角速度传感器和无外部传感器辅助下姿态参数估计的状态模型;利用自适应抗差滤波估计姿态误差,借鉴分类自适应因子的思想,分别确定模糊度和姿态误差参数的自适应因子,其中姿态自适应因子由Ratio值构造的三段函数确定。自适应抗差滤波能够充分利用约束信息和历史信息,将其融合在浮点解计算过程中,极大提高模糊度浮点解精度及其协方差的结构,在此基础上使用整数最小二乘模糊度降相关平差法(least-squares ambiguity decorrelation adjustment,LAMBDA)方法即能快速搜索出固定解,满足实时性需求。采用实测舰载GNSS 3天线测姿算例对方法进行了验证,结果表明,基于自适应抗差滤波的观测值直接定姿方法效率高、可靠性好。 相似文献
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Single receiver phase ambiguity resolution with GPS data 总被引：26，自引：12，他引：14
Willy Bertiger Shailen D. Desai Bruce Haines Nate Harvey Angelyn W. Moore Susan Owen Jan P. Weiss 《Journal of Geodesy》2010,84(5):327-337
Global positioning system (GPS) data processing algorithms typically improve positioning solution accuracy by fixing double-differenced
phase bias ambiguities to integer values. These “double-difference ambiguity resolution” methods usually invoke linear combinations
of GPS carrier phase bias estimates from pairs of transmitters and pairs of receivers, and traditionally require simultaneous
measurements from at least two receivers. However, many GPS users point position a single local receiver, based on publicly
available solutions for GPS orbits and clocks. These users cannot form double differences. We present an ambiguity resolution
algorithm that improves solution accuracy for single receiver point-positioning users. The algorithm processes dual- frequency
GPS data from a single receiver together with wide-lane and phase bias estimates from the global network of GPS receivers
that were used to generate the orbit and clock solutions for the GPS satellites. We constrain (rather than fix) linear combinations
of local phase biases to improve compatibility with global phase bias estimates. For this precise point positioning, no other
receiver data are required. When tested, our algorithm significantly improved repeatability of daily estimates of ground receiver
positions, most notably in the east component by approximately 30% with respect to the nominal case wherein the carrier biases
are estimated as real values. In this “static” test for terrestrial receiver positions, we achieved daily repeatability of
1.9, 2.1 and 6.0 mm in the east, north and vertical (ENV) components, respectively. For kinematic solutions, ENV repeatability
is 7.7, 8.4, and 11.7 mm, respectively, representing improvements of 22, 8, and 14% with respect to the nominal. Results from
precise orbit determination of the twin GRACE satellites demonstrated that the inter-satellite baseline accuracy improved
by a factor of three, from 6 to 2 mm up to a long-term bias. Jason-2/Ocean Surface Topography Mission precise orbit determination
tests results implied radial orbit accuracy significantly below the 10 mm level. Stability of time transfer, in low-Earth
orbit, improved from 40 to 7 ps. We produced these results by applying this algorithm within the Jet Propulsion Laboratory’s
(JPL’s) GIPSY/OASIS software package and using JPL’s orbit and clock products for the GPS constellation. These products now
include a record of the wide-lane and phase bias estimates from the underlying global network of GPS stations. This implies
that all GIPSY–OASIS positioning users can now benefit from this capability to perform single-receiver ambiguity resolution. 相似文献