Improvement of Augmented Multi-Constellation Satellite-Based Precise Positioning in a Wide Range of Environments

虽然GPS是第一个广泛使用的卫星导航系统，它现在已经加入了俄罗斯的GLONASS系统，并将很快加入欧洲的伽利略系统、中国的北斗系统和日本的qzss系统，所有这些系统现在都有在轨测试卫星。要想从大量的全球导航卫星系统（GNSS）中获得最大的利益，实现精确定位和导航，有许多有趣的问题需要解决，我提出的探索基金研究将解决其中的一些问题。通过使用所有可用卫星的观测数据，无论星座如何，我们都有可能在某些方向的信号可能被阻挡的受限环境中显著提高导航的可用性和连续性。我们也有潜力提高定位精度，由于更多的观测与更有利的几何。我们已经通过将GPS观测结果与伽利略测试卫星的观测结果相结合来证明这一点。如何将不同系统的测量结果与不同的参考基准、参考时间系统、系统偏差、信号类型、测量精度和精度结合起来，是需要研究的问题。还需要开发算法和相关软件，以最佳地处理观测结果。我们已经实现了结合GPS和GLONASS传统信号数据的最佳方法，并将扩展到其他星座的数据。除获取增强数据外，在低于标准的环境中进行高精度GNSS定位还受到其他困难的阻碍。例如，在极光和极区，电离层经常受到干扰，导致闪烁的观测结果，在记录的载波相位数据中经常包括周期滑动或跳跃。我的研究小组在开发周期滑移的检测和修复方法方面取得了重大进展。然而，这些技术并非万无一失，需要对周期滑移问题进行进一步的研究。新的GNSS以及现代化的GPS将在多个频率上提供新的信号结构，这将极大地有利于定位和导航。我的小组已经做了一些开创性的工作来展示一些优势，随着GPS Block IIF/III、伽利略和北斗星座的建立，我们将进行进一步的调查，同时使用新的信号来实施GLONASS星座。我们的工作还包括加强对大气影响的模拟。我们将研究GNSS接收机在受干扰电离层条件下的性能，包括使用GPS作为遥感工具来研究电子分布的形态。我们的这一部分工作将利用来自地面GPS接收器的数据，包括目前由UNB部署的扩展的加拿大高北极电离层网络的数据。我们还将开始分析2013年9月底发射的加拿大CASSIOPE科学卫星上基于gps的仪器的数据。我们的一些工作将与国际GNSS服务（IGS）多GNSS实验和IGS实时试点项目进行协调，这是我们已经参与的两项国际GNSS活动。我们提出的所有GNSS研究将对加拿大和世界范围内的定位和导航产生重大影响。

Although GPS was the first widely available satellite navigation system, it has now been joined by the Russian GLONASS system, and will soon be joined by the European Galileo system, the Chinese BeiDou system and the Japanese QZSS—all of which have test satellites now in orbit. There are a number of interesting problems to be solved in gaining maximum benefits from this plethora of global navigation satellite systems (GNSS) for precise positioning and navigation, and my proposed Discovery Grant research will address a number of them.By using observations from all available satellites, regardless of constellation, we have the possibility of significantly improving navigation availability and continuity in restricted environments where signals from some directions might be blocked. We also have the potential for improved positioning accuracy due to the availability of more observations with more favourable geometry. We have already demonstrated this by combining GPS observations with those from one of the Galileo test satellites. Research is needed on how to best combine measurements from the different systems with different reference datums, reference time systems, system biases, signal types, and measurement accuracies and precisions. The algorithms and associated software for optimally processing the observations also need to be developed. We have already achieved an optimum approach for combining GPS and GLONASS legacy signal data and will extend it for data from the other constellations.High-accuracy GNSS positioning in sub-par environments is hampered by other difficulties besides access to augmentation data. For example, in the auroral and polar regions, the ionosphere can be often disturbed resulting in scintillating observations that frequently include cycle slips or jumps in the recorded carrier-phase data. My research group has made significant progress in developing approaches for the detection and repair of cycle slips. However, the techniques are not infallible and further research into the problem of cycle slips is required. The new GNSS along with modernized GPS will offer new signal structures on multiple frequencies that will greatly benefit positioning and navigation. My group has done some pioneering work to demonstrate some of the advantages and we will carry out further investigations as the GPS Block IIF/III, Galileo, and BeiDou constellations are built up along with the use of the new signals to be implemented for the GLONASS constellation.Our work will also involve enhanced modelling of atmospheric effects. We will be investigating GNSS receiver performance in disturbed ionospheric conditions, including the use of GPS as a remote-sensing tool for studying the morphology of the electron distribution. This part of our work will make use of data from terrestrial GPS receivers including those of the expanded Canadian High Arctic Ionospheric Network currently being deployed by UNB. We will also begin the analysis of data from our GPS-based instrument on the Canadian CASSIOPE scientific satellite launched at the end of September 2013.Some of our work will be coordinated with the International GNSS Service (IGS) Multi-GNSS Experiment and the IGS Real Time Pilot Project—two IGS activities in which we already participate.All of our proposed GNSS research will be of significant benefit for positioning and navigation in Canada and worldwide.