Space weather hazards: Monitoring and mitigation for GNSS

基于卫星的导航系统，如全球定位系统（GPS）在UHF范围内工作，通常在1.1到1.6 GHz之间。这些l波段信号容易受到电离层折射和由于加拿大纬度电离层闪烁引起的快速随机相位和振幅变化的影响。大的定位误差与该地区电离层活动水平高有关，并且在闪烁事件期间观测到信号可用性的损失，损害了安全关键导航系统（例如海上导航或商业航空）的完整性和可靠性。附加的GPS信号和新的全球导航卫星系统（GNSS）伽利略将在未来几年内可用，太阳周期高峰预计在2010年中期出现。GPS/GNSS应用是一个价值数十亿美元的产业，加拿大需要为GNSS应用开发空间天气预警和警报。在本文提出的研究中，将对GNSS的空间天气危害进行表征，并对各种导航应用的影响进行量化。将开发算法来实时监测包括闪烁在内的重要空间天气影响。通过与加拿大地质调查局的合作，这项技术将被转让，以便在一项业务服务中实际实施。通过与工业界合作并使用最先进的GNSS软件接收器，将调查和减轻电离层闪烁的影响。将开发稳健的接收机跟踪回路，以提高GNSS观测的可用性和可靠性。总的来说，加拿大的卫星导航系统的导航完整性将得到改善。

Satellite-based navigation systems such as the Global Positioning System (GPS) operate in the UHF range, which is typically between 1.1 and 1.6 GHz. These L-band signals are susceptible to ionospheric refraction and rapid random phase and amplitude variations due to ionospheric scintillations at Canadian latitudes. Large positioning errors are associated with high levels of ionospheric activity in this region, and losses of signal availability have been observed during scintillation events, with compromised integrity and reliability of safety-critical navigation systems (e.g. marine navigation or commercial aviation). Additional GPS signals and a new global navigation satellite system (GNSS), Galileo, will become available in the next several years, and a solar cycle peak is expected mid-2010. GPS/GNSS applications are a multi-billion dollar industry, and a need exists to develop space weather warnings and alerts for GNSS applications in Canada. In the research proposed here, space weather hazards for GNSS will be characterized and the impact quantified for various navigation applications. Algorithms will be developed to monitor space weather effects of significance, including scintillations, in real-time. Through partnership with the Geological Survey of Canada, this technology will be transferred for practical implementation in an operational service. By partnering with industry and using a state-of-the-art GNSS software receiver, the effects of ionospheric scintillation will be investigated and mitigated. Robust receiver tracking loops will be developed for improved availability and reliability of GNSS observations. Overall, it is intended that navigation integrity will be improved for satellite-based navigation systems in Canada.