共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
周跳探测是GPS数据处理的重要课题。根据所得数据的类型,例如码伪距和相位伪距等,已有多种方法。总的说来,每种方法都各有其优缺点。本文提出两步探测法,用来探测周跳,在建立起检验量后,从平滑角度对其探测功能进行,检定,一旦出现间断,就说明存在周跳。 相似文献
3.
4.
5.
GPS相位观测值中周跳的探测与修复 总被引:4,自引:0,他引:4
在GPS测量中,如何对载波相位观测值中的周跳进行探测和修复,是精密定位数据处理中的一个十分重要的问题,本文首先概述了周跳的产生、定义及其来源,其次介绍了不同周跳检验量的构成,然后重点讨论了周跳检验的若干方法,最后引出了几点结论。 相似文献
6.
7.
8.
周跳的探测一直以来都是GPS载波相位测量数据预处理的一个重点和难点,准确探测周跳有利于整周模糊度的确定,大大地提高了GPS的定位精度.文章利用集合卡尔曼滤波模型对GPS周跳问题进行探测研究,针对静态载波相位数据给出了最佳的参数量,进行周跳探测试验,从理论和实践上证明了该模型对GPS周跳探测的可行性和有效性. 相似文献
9.
10.
建立了GPS/INS紧组合定位模型,改正惯性器件误差及电离层折射误差,对不同组合观测量的误差影响进行了分析,构造不同观测值组合,提出了基于惯性信息辅助的GPS周跳自适应探测方法,分析了INS定位误差对周跳探测的影响,给出了周跳探测误报率及修复成功率评价指标,提出了一种周跳检测阈值自适应确定方法。利用实测组合导航试验数据验证本文的算法,文中模拟了不同的单历元多周跳及信号失锁条件,结果表明,在GPS信号完全失锁20 s内,该方法能准确检测和修复所有周跳,中断时间的延长降低了周跳修复的成功率;GPS信号部分失锁时,在模拟的90 s中断时段内仍能修复所有周跳;模拟了170历元的5 s间隔密集周跳,周跳探测成功率为100%,正确修复率为99.41%。 相似文献
11.
12.
13.
14.
15.
Integer carrier-phase ambiguity resolution is one of the critical issues for precise GPS applications in geodesy and geodynamics. To resolve as many integer ambiguities as possible, the ‘most-easy-to-fix’ double-difference ambiguities have to be defined. For this purpose, several strategies are implemented in existing GPS software packages, such as choosing the ambiguities according to the baseline length or the variances of the estimated real-valued ambiguities. Although their efficiencies are demonstrated in practice, it is proven in this paper that they do not reflect all effects of varying data quality, because they are based on theoretical considerations of GPS data processing. Therefore, a new approach is presented, which selects the double-difference ambiguities according to their probability of being fixed to the nearest integer. The probability is computed from estimates and variances of wide-lane and narrow-lane ambiguities. Together with an optimized ambiguity fixing procedure, the new approach is implemented in the routine data processing for the International GPS Service (IGS) at GeoForschungsZentrum (GFZ) Potsdam. Within a sub-network of about 90 IGS stations, it is demonstrated that more than 97% of the independent ambiguities are fixed correctly compared to 75% by a commonly used method, and that the additionally fixed ambiguities improve the repeatability of the station coordinates by 10–26% in regions with sparse site distribution. 相似文献
16.
本文基于多频组合观测值探测周跳的原理,利用模拟的GPS L5数据与L1、L2进行不同的线性组合,选取(0,1,-1)、(-1,8,-7)和(1,-6,5)3个波长较长、线性不相关且几何距离无关、观测噪声较小的组合,对实测数据人为加入了大小不同的周跳组合,周跳探测结果表明,三频甚至多频组合观测值能够实时探测各种情况下的周跳。 相似文献
17.
18.
19.
20.
Efficiency of carrier-phase integer ambiguity resolution for precise GPS positioning in noisy environments 总被引:1,自引:0,他引:1
Precise GPS positioning relies on tracking the carrier-phase. The fractional part of carrier-phase can be measured directly
using a standard phase-locked loop, but the integer part is ambiguous and the ambiguity must be resolved based on sequential
carrier-phase measurements to ensure the required positioning precision. In the presence of large phase-measurement noise,
as can be expected in a jamming environment for example, the amount of data required to resolve the integer ambiguity can
be large, which requires a long time for any generic integer parameter estimation algorithm to converge. A key question of
interest in significant applications of GPS where fast and accurate positioning is desired is then how the convergence time
depends on the noise amplitude. Here we address this question by investigating integer least-sqaures estimation algorithms.
Our theoretical derivation and numerical experiments indicate that the convergence time increases linearly with the noise
variance, suggesting a less stringent requirement for the convergence time than intuitively expected, even in a jamming environment
where the phase noise amplitude is large. This finding can be useful for practical design of GPS-based systems in a jamming
environment, for which the ambiguity resolution time for precise positioning may be critical. 相似文献