The least-squares ambiguity decorrelation adjustment: its performance on short GPS baselines and short observation spans
The least-squares ambiguity decorrelation adjustment: its performance on short GPS baselines and short observation spans
复制标题
DOI：
10.1007/s001900050127
复制
发表时间：
1997-09-01
影响因子：
4.4
通讯作者：
Tiberius, CCJM
中科院分区：
文献类型：
--
作者：
Teunissen, PJG;deJonge, PJ;Tiberius, CCJM
最小二乘模糊度去相关调整是一种快速GPS双差(DD)整数模糊度估计的方法。将讨论该方法的性能，尽管强调该方法是普遍适用的，但在本贡献中，注意力仅限于短基线应用。参考模糊度搜索空间的大小和形状，引入搜索空间的体积作为候选网格点数量的度量，并使用条件方差谱的签名来识别计算整数DD模糊度的难度。结果表明，当整数最小二乘模糊度搜索发生在原始 DD 模糊度空间中时，搜索效果很差。这种糟糕的表现可以用条件方差谱的不连续性来解释。结果表明，通过模糊度的去相关，获得了变换后的模糊度，其通常具有平坦且较低的频谱，从而实现快速且高效的搜索。它还展示了如何使用变换后的模糊度的高精度和低相关性来缩放搜索空间，以避免大量不必要的候选网格点。数值结果显示在条件方差谱以及原始模糊度和转换模糊度的统计数据上。除了提供通常可以实现的数值结果外，该贡献还强调并解释了不同测量场景对方法性能的影响，例如卫星冗余、单频数据与双频数据、代码数据的包含以及观测时间跨度的长度。
The least-squares ambiguity decorrelation adjustment is a method for fast GPS double-difference (DD) integer ambiguity estimation. The performance of the method will be discussed, and although it is stressed that the method is generally applicable, attention is restricted to short-baseline applications in the present contribution. With reference to the size and shape of the ambiguity search space, the volume of the search space will be introduced as a measure for the number of candidate grid points, and the signature of the spectrum of conditional variances will be used to identify the difficulty one has in computing the integer DD ambiguities. It is shown that the search for the integer least-squares ambiguities performs poorly when it takes place in the space of original DD ambiguities. This poor performance is explained by means of the discontinuity in the spectrum of conditional variances. It is shown that through a decorrelation of the ambiguities, transformed ambiguities are obtained which generally have a flat and lower spectrum, thereby enabling a fast and efficient search. It is also shown how the high precision and low correlation of the transformed ambiguities can be used to scale the search space so as to avoid an abundance of unnecessary candidate grid points. Numerical results are presented on the spectra of conditional variances and on the statistics of both the original and transformed ambiguities. Apart from presenting numerical results which can typically be achieved, the contribution also emphasizes and explains the impact on the method's performance of different measurement scenarios, such as satellite redundancy, single vs dual-frequency data, the inclusion of code data and the length of the observation time span.