Real-time GPS/Galileo precise point positioning

精确点定位（PPP）是一种不断发展的技术，它采用单一的全球导航卫星系统（GNSS）接收机。事实证明，PPP能够在静态和运动模式下分别提供亚分米和分米级精度的定位解决方案。然而，不幸的是，目前PPP解决方案需要大约20分钟才能收敛到分米级别的精度。这反过来又减慢了许多用户采用该技术的速度。

Precise point positioning (PPP) is an evolving technique, which employs a single global navigation satellite system (GNSS) receiver. PPP proved to be capable of providing positioning solution at the sub-decimeter and decimeter-level accuracy in static and kinematic modes, respectively. Unfortunately, however, at present the PPP solution takes approximately 20 minutes to converge to a decimeter-level accuracy. This in turn slows down the adoption of the technique by many users. Tulloch Engineering, an Ontario-based geomatics consultancy firm, is currently engaged in many positioning activities. The company relies essentially on the real-time positioning service through the virtual reference station (VRS) technique. Unfortunately, however, the coverage of Ontario's VRS systems is limited to a small region of the province. When VRS system is unavailable, Tulloch uses the PPP technique, despite its slow solution convergence at present. To increase the company's productivity, Tulloch Engineering is interested in adopting a technique that reduces the PPP convergence time without affecting the positioning accuracy. The major objective of the proposed research is to develop algorithms and estimation methodologies for real-time GPS/Galileo PPP. This in turn requires that the ambiguity parameters be fixed to their correct integer values on the fly. A major problem to realize this, however, is the presence of the receiver and the satellite un-calibrated hardware delays. To overcome this problem, improved precise satellite products and calibrated hardware delays should be produced and applied to the PPP model. As most of Canada's high latitude regions have no GNSS VRS networks, real-time GPS/Galileo PPP can be the solution for precise positioning application. As such, the outcome of project will increase the productivity, efficiency and operation cost for Tulloch Engineering (and other Canadian companies). Other industries, such as mining and offshore, will also benefit from the developed technique. The project will also contribute to the scientific excellence of Canada as a technological hub for innovative techniques.