In recent years, global navigation satellite system (GNSS) precise point positioning (PPP) has become a standard positioning technique for many applications with typically favourable open sky conditions, e.g. precision agriculture. Unfortunately, the long convergence (and reconvergence) time of PPP often significantly limits its use in difficult and restricted signal environments typically associated with urban areas. The modernisation of GNSS will positively affect and improve the convergence time of the PPP solutions, thanks to the higher number of satellites in view that broadcast multifrequency measurements. The number and geometry of the available satellites is a key factor that impacts on the convergence time in PPP, while triple-frequency observables have been shown to greatly benefit the fixing of the carrier phase integer ambiguities. On the other hand, many studies have shown that triple-frequency combinations do not usefully contribute to a reduction of the convergence time of float PPP solutions.This paper proposes novel GPS and Galileo triple-carrier ionosphere-free combinations that aim to enhance the observability of the narrow-lane ambiguities. Tests based on simulated data have shown that these combinations can reduce the convergence time of the float PPP solution by a factor of up to 2·38 with respect to the two-frequency combinations. This approach becomes effective only after the extra wide-lane and wide-lane ambiguities have been fixed. For this reason, a new fixing method based on low-noise pseudo-range combinations corrected by the smoothed ionosphere correction is presented. By exploiting this algorithm, no more than a few minutes are required to fix the WL ambiguities for Galileo, even in cases of severe multipath environments.

中文翻译：

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GPS 和伽利略三载波无电离层组合，用于提高精确点定位的收敛性

近年来，全球导航卫星系统 (GNSS) 精确单点定位 (PPP) 已成为许多具有典型有利开阔天空条件的应用的标准定位技术，例如精准农业。不幸的是，PPP 的长收敛（和再收敛）时间通常极大地限制了其在通常与城市地区相关的困难和受限信号环境中的使用。鉴于广播多频测量的卫星数量增加，GNSS 的现代化将积极影响和改善 PPP 解决方案的收敛时间。可用卫星的数量和几何形状是影响 PPP 收敛时间的关键因素，而三频可观测数据已被证明极大地有利于载波相位整数模糊度的固定。另一方面，许多研究表明，三频组合对缩短浮动 PPP 解决方案的收敛时间没有帮助。本文提出了新的 GPS 和 Galileo 三载波无电离层组合，旨在提高可观测性窄巷歧义。基于模拟数据的测试表明，这些组合可以将浮动 PPP 解决方案的收敛时间相对于双频组合减少高达 2·38 倍。这种方法只有在修正了额外的宽车道和宽车道的模糊性之后才有效。为此，提出了一种基于平滑电离层校正的低噪声伪距组合的固定方法。通过利用该算法，